ACVIM Required Literature - Respiratory Dz Flashcards

Question

Are there other miscellaneous nonpharmacological treatments to prevent EIPH?

Answer 1

The studies provided very low quality evidence that herbal preparations or inhaled water vapor affect EIPH severity. Ref: ACVIM Consensus Statement (2015) - EIPH.

Answer 2

There is moderate quality evidence that furosemide administered IV 4 hours prior to racing is associated with improved racing outcomes in TB and SB racehorses. Ref: ACVIM Consensus Statement (2015) - EIPH.

Answer 3

There is low quality evidence that furosemide administered IV 4 hours before treadmill exercise results in delayed onset of fatigue and improved energetic cost of locomotion. Ref: ACVIM Consensus Statement (2015) - EIPH.

Answer 4

Bacteriologic culture or amplification of the vapA gene using PCR from a tracheobronchial aspirate (TBA) obtained from a foal with one or more of the following: (1) Clinical signs of lower respiratory tract disease; (2) Cytological evidence of septic airway inflammation; or (3) Radiographic or u/s evidence of bronchopneumonia. Ref: ACVIM Consensus Statement (2011) - R. Equi.

Answer 5

- Bacteriologic culture or PCR amplification of vapA from samples from the site of infection if sampling possible. - If from site which cannot be sampled e.g. uveitis, dx should be based on isolation of R. equi from a TBA or other primary sites of infection. Ref: ACVIM Consensus Statement (2011) - R. Equi.

Answer 6

- No. - R. equi can be cultured from the faeces of healthy horses even if they live at farms w/o a Hx of R. equi pneumonia. Ref: ACVIM Consensus Statement (2011) - R. Equi.

Answer 7

- A macrolide (erythromycin, azithromycin, or clarithromycin) plus rifampin based on in vitro activity data, pharmacokinetic studies, and retrospective studies. Ref: ACVIM Consensus Statement (2011) - R. Equi.

Answer 8

- Considerably enhanced oral bioavailabilities especially in the absence of fasting. - Prolonged half lives. - Much higher concentrations in pulmonary epithelial lining fluid (PELF) and bronchoalveolar cells. Ref: ACVIM Consensus Statement (2011) - R. Equi.

Answer 9

- Resolution of clinical signs. - Normalisation of plasma fibrinogen concentrations. - Radiographic or u/s resolution of lung lesions. Ref: ACVIM Consensus Statement (2011) - R. Equi.

Answer 10

- Diarrhoea: often self limiting but may become severe; 17-36% foals on erythromycin. - Hyperthermia: may be fatal; continues 4+ weeks post-tx. - Fatal enterocolitis in mare ingesting small amounts of macrolides foals transferred to feed/water. Ref: ACVIM Consensus Statement (2011) - R. Equi.

Answer 11

- Tulathromycin and tilmicosin: no, both have very poor activity against R. equi. - Gamithromycin: active against R. equi in vitro; 6mg/kg IM --> bronchoalveolar cell concentrations above the MIC90 for approximately 7 days; tx not recommended until clinical efficacy and safety have been established in foals. Ref: ACVIM Consensus Statement (2011) - R. Equi.

Answer 12

Macrolide- and rifampin-resistant isolates of R. equi are susceptible in vitro to fluoroquinolones, aminoglycosides, oxazolidinones, and glycopeptide antimicrobials. - In 1 study, 18 of 24 isolates were also susceptible to chloramphenicol, tetracycline, and TMPS. - Currently there are no data to indicate the preferred antimicrobial agent(s) for the tx of resistant infections. - Oral doxycycline + rifampin has been used with anecdotal success; 10mg/kg PO BID --> serum, pulmonary epithelial lining fluid, and bronchoalveolar cell concentrations above the MIC90 of R. equi isolates for the entire dosing interval. - Chloramphenicol achieves high conc within phagocytic cells in other species. However, the fact that only 70% of R. equi isolates are susceptible and the potential human health risk make this drug a less attractive alternative. - High doses of TMPS (30 mg/kg q8-12 h PO) have been used alone or in combination with rifampin in foals with mild or early R. equi pneumonia, or for continued treatment in foals responding well to other antimicrobials. Ref: ACVIM Consensus Statement (2011) - R. Equi.

Answer 13

- Nursing care, adequate nutrition and hydration, maintaining the foal in a cool and well-ventilated enviro. - Humidified oxygen delivered by pharyngeal insufflation in moderately hypoxemic foals, or by percutaneous transtracheal oxygenation in severely hypoxemic patients. - NSAIDs to reduce fever and impr attitude and appetite. - Nebulization with saline, antimicrobial agents, or bronchodilators has been advocated but there are no data to either support or refute these therapeutic practices. - Immune-mediated extrapulmonary disorders e.g polysynovitis generally resolve with successful tx of the accompanying pneumonia. - Foals with R. equi septic arthritis or osteomyelitis often require aggressive local treatment e.g. joint lavage, surgical debridement, and IV or intraosseous RLP. - Abdominal abscesses: surgical removal or marsupialization has been attempted but abdominal adhesions usually result in inability to resect the abscess. Ref: ACVIM Consensus Statement (2011) - R. Equi.

Answer 14

- Reports vary. - Referral hospital (severe cases): 59-72% - On farm: up to 100%. Ref: ACVIM Consensus Statement (2011) - R. Equi.

Answer 15

Prognosis for performance after successful treatment of uncomplicated R. equi pneumonia should be regarded as excellent. Ref: ACVIM Consensus Statement (2011) - R. Equi.

Answer 16

- White blood cell concentrations performed at monthly intervals. - Thoracic ultrasound. Ref: ACVIM Consensus Statement (2011) - R. Equi.

Answer 17

- Serum concentrations of antibodies against R. equi. - Serum amyloid A concentration. - Plasma fibrinogen concentration. Ref: ACVIM Consensus Statement (2011) - R. Equi.

Answer 18

- Mass antimicrobial treatment of all foals with small subclinical pulmonary abscesses was unnecessary in a recent trial (no adv azith/rif over no tx). - The extent to which these results may be extrapolated to other farms remains unknown because the proportion of foals that recover without tx may vary by farm, geographic region, and age at which foals lesions are detected. Ref: ACVIM Consensus Statement (2011) - R. Equi.

Answer 19

Chemoprophylaxis with macrolides or other classes of antimicrobial drugs is not recommended because of conflicting evidence of efficacy and concerns for promoting resistance of R. equi and other bacteria to these drugs. Ref: ACVIM Consensus Statement (2011) - R. Equi.

Answer 20

Although R. equi pneumonia has been positively assoc with the density of mares/foals at farms and airborne conc of virulent R. equi, and neg associated with foaling at pasture, there is inadequate evidence to recommend environmental interventions to control or prevent R. equi pneumonia. Ref: ACVIM Consensus Statement (2011) - R. Equi.

Answer 21

- Administration of commercially available and licensed plasma containing antibody against R. equi is recommended as an aid for prevent-ing pneumonia caused by R. equi at endemic farms. - Transfusion of HIP is not completely effective and therefore does not eliminate the need for screening or careful monitoring of foals at risk. Ref: ACVIM Consensus Statement (2011) - R. Equi.

Answer 22

- There is inadequate evidence to recommend active immunisation of mares or foals to control or prevent R. equi pneumonia. - The evidence from mouse models, immune adult horses, and the study of other similar intracellular pathogens strongly suggests that an active immunization strategy to prevent R. equi disease will need to induce antigen-specific Type 1 cell-mediated responses. Antibody responses alone are unlikely to be protective.

Answer 23

Isolation of multiple bacteria or fungi from a TBA along with R. equi does not negatively impact prognosis. Ref: J. Vet. Intern. Med. 2012; 26(6):1443–1448.

Answer 24

- The presence an 85- to 95-kDa virulence-assoc plasmid and the expression of the virulence-assoc protein A (VapA). - R. equi isolates from horses or their environments are commonly classified as either virulent or avirulent, based on the presence or absence of VapA. Ref: J. Vet. Intern. Med. 2013; 27(6):1555–1562.

Answer 25

- In an in vitro study examining isolates from foals and their environment, transfer of the virulence plasmid occurs with relatively high frequency. - These findings could impact strategies to control or prevent R. equi through environmental management. Ref: J. Vet. Intern. Med. 2013; 27(6):1555–1562.

Answer 26

- No. - Randomised, double-blind, prospective study of 108 foals with lesions 5-10cm: tulathromycin, doxy, doxy/rif, azith/rif and saline. - 88% of control group recovered without need for tx. - Time to recover shorter with azith/rif vs placebo. - The proportion of foals that had evidence of dz progression did not differ sig between the tx groups. - The majority of foals with subclinical pulmonary abscesses

Answer 27

- Gallium maltolate is not inferior to macrolides for treating foals with subclinical pneumonia. - NB Multiple limitations in this study. Ref: J. Vet. Intern. Med. 2015; 29(3):932–93.

Answer 28

- First CSx usually b/w 3 and 24 weeks of life, with most foals showing signs before 16 weeks of age. - Infections are uncommon among horses > 6mo. - In a report of 161 foals e R. equi pneumonia: cough (71%), fever (68%), lethargy (53%), and inc respiratory effort (43%). Ref: J. Vet. Intern. Med. 2011; 25(6):1221–1230.

Answer 29

- Polysynovitis (~24-33%): immune-mediated or septic. - Abdominal disorders (50% foals presented for necropsy): pyogranulomatous enterotyphylocolitis, pyogranulomatous lymphadenitis of the mesenteric or colonic lymph nodes large intra-abdominal abscesses and peritonitis. - Ocular lesions incl uveitis, keratouveitis, panophthalmitis. - Osteomyelitis. - Septic synovitis (vs polysynovitis above which is a reaction to bacteria which is cleared early). - Pyogranulomatous mediastinal lymphadenopathy. - Abscess in liver, kidney, spleen, or nervous tissue/brain. - Less common EPDs: pericarditis, endocarditis, cellulitis, dermatitis, subcutaneous abscesses, peripheral lymphadenopathy, guttural pouch empyema, pleuritis, sinusitis, myositis, stomatitis, pyometra and omphalitis. - Immune-mediated hemolytic anemia, immune-mediated thrombocytopenia, and telogen effluvium. Ref: J. Vet. Intern. Med. 2011; 25(6):1221–1230.

Answer 30

- Inhalation of virulent R. equi is the major route of pulmonary infection. - Ingestion important route of exposure and likely immunisation but rarely --> pneumonia. - Incubation period after experiment challenge: 9d - 4wk. - Incubation period under field conditions is unknown; likely depends on several factors e.g. number of virulent bacteria in air samples, age of foal, host defence mechanisms. - Most foals on endemic farms become infected early in life --> median age at time of dx is 35-50d on endemic farms. - In 1 study, foals aged between 3 and 13 days were more susceptible to experimentally induced R. equi pneumonia than foals aged between 14 and 36 days. - Older foals are also susceptible; experimental infection of 10 foals aged 27-67 days --> infection in all. Ref: J. Vet. Intern. Med. 2011; 25(6):1221–1230.

Answer 31

- Once inhaled, R. equi is taken up by alveolar macrophages through a process of receptor-mediated phagocytosis incl complement receptor 3 (CR3 or Mac-1) and possibly the macrophage mannose receptor. - Once engulfed by macrophages, virulent R. equi modify the phagocytic vacuole to prevent acidification and subsequent fusion with lysosomes. - Bacterial gene expression patterns are altered to accom survival in the intracellular enviro, allow acquisition of essential nutrients e.g. iron, as and promote resistance to host-derived ROIs. - Uncontrolled intracellular replication of R. equi leads to necrosis of the macrophage. - If opsonized with R. equi-specific antibody, the fate of the R. equi containing phagosome is altered and lysosome fusion occurs. - In mouse models killing of R. equi by macrophages depends on TNF-a and IFN-c. - As opposed to macrophages, neuts from foals and adult horses are fully able to kill R equi --> imp early defence. Ref: J. Vet. Intern. Med. 2011; 25(6):1221–1230.

Answer 32

- The strongest evidence for a role of antibody in protection against R. equi is the partially protective effect of passively transferred anti- R. equi hyperimmune equine plasma. - Because of the facultative intracellular nature of R. equi, CMI mechanisms are of major importance in inf resistance. - Although both CD4+ (helper) and CD8+ (cytotoxic) T cells contribute to host defense against R. equi in mice, CD4+ T lymphocytes probably play the major role. - Studies in mice have clearly shown that a Type 1 response, charac by IFN-gamma prod by T helper lymphocytes, is sufficient to effect pulmonary clearance of R. equi whereas a Type 2 response, charac by IL-4 prod, is detrimental. - Clearance of virulent R. equi in immune adult horses is associated with lymphoproliferative responses to R. equi antigens, development of R. equi-specific cytotoxic T lymphocytes (CTL), and IFN-g induction. Ref: J. Vet. Intern. Med. 2011; 25(6):1221–1230.

Answer 33

- Neonates and perinates have diminished innate immune responses, decreased antigen-presenting cell function, and are less able to mount type-1 immune responses. - Age-related deficiencies in R. equi-specific CTL activity has been documented in 3wk old foals. --> n by 8wk old. - Antigen-presenting cells from foals have significantly lower CD1 and MHC class II expression vs adult horses. - Young foals are deficient in their ability to prod IFN-c in response to mitogens --> hypoth IFN-g deficiency and Th2 bias might be basis of foals' susceptibility to R. equi infect. - However studies demonstration foals are deficient in IL-4 in response to stim with mitogens and after vacc --> clear polarisation toward a Th2 resp is unlikely in neonatal foals. - Experimental infect of foals with virulent R. equi results in IFN-g induction and Ab resp similar to/greater than adults. - Oral inoculation with virulent R. equi results in accelerated development of R. equi-specific CTL. - Collectively, these findings unequivocally demonstrate that most foals have the ability to mount protective immune responses to R. equi. - The basis for the peculiar susceptibility of foals to infection with R. equi is likely complex and multifactorial. Ref: J. Vet. Intern. Med. 2011; 25(6):1221–1230.

Answer 34

- In a study of 124 horses admitted to Michigan State Teaching Hospital, none were positive for EHV-1 DNA in buffy coat or nasal swab samples. - Conclusion: nasal shedding and viremia of EHV-1 in hospitalized critically- ill horses with acute abdominal disorders is extremely rare. Ref: J. Vet. Intern. Med. 2011; 25(5):1190–1193.

Answer 35

- Serum iron concentration decreases significantly in a biphasic pattern after EHV-1 infection. - There was no significant difference in sFe concentration in horses that developed neurologic disease and those that did not in these experimentally infected animals. Ref: J. Vet. Intern. Med. 2011; 25(5):1190–1193.

Answer 36

- 230 (9.7%) index cases tested qPCR positive for EIV. - A higher-than-expected proportion of EIV qPCR-positive horses occurred in the 1–5, 6–10, and 11–15 age groups when compared to the

Answer 37

- Hypertrophic osteoarthropathy. - Presented for hard swellings on the distal radii, distal tibias, proximal metatarsi and left metacarpus and fever. - Pulmonary abscesses, pulmonary neoplasia, granulomatous pneumonia and rib fracture with pleural adhesions. Ref: J. Vet. Intern. Med. 2011; 25(1):153–157.

Answer 38

- Asinine Herpesvirus-5. - Pyogranulomatous pneumonia was diagnosed in this case of persistent respiratory disease, and AsHV-5 was detected in lung tissue collected from the affected animal. - This virus also was detected in nasal secretions from 3 animals in direct contact with the mare, including 2 donkeys and 1 horse. Ref: J. Vet. Intern. Med. 2012; 26(4):1064–1068.

Answer 39

- >70% horses had IAD in the first month of training regardless of management group. - Median respirable particulates were significantly higher when horses were fed from hay nets than the ground. - Inhalable particulate and respirable endotoxin exposures were sig higher when horses were fed from hay nets. - Feeding hay from a net resulted in significantly higher BALF eosinophil proportions over time. - BALF eosinophils were significantly related to respirable particulate exposure. Ref: J. Vet. Intern. Med. 2014; 28(3):918–924.

Answer 40

- TNF-a and IFN-gamma concentrations were significantly higher for IAD horses, compared with controls. - Horses with ‘neutrophil’ subtype had significantly higher IFN-gamma concentrations than ‘neutrophil/metachromatic’ and ‘neutrophil/metachromatic/eosinophil’ subtypes. - IL-4 conc in BALF was not modified by any condition. - Data from this study might suggest a predominant Th1-cell response, while cytokine mRNA expression in previous studies revealed either no Th polarisation or a Th2-cell predominance, or a mixed Th1/Th2 response. - TNF-a concentrations in BALF suggested the involvement of pulmonary innate immune response in the pathogenesis of IAD. Ref: J. Vet. Intern. Med. 2014; 28(6):1838–1844.

Answer 41

Serum amyloid A, C-reactive protein and haptoglobin were not helpful in distinguishing between horses with IAD from horses with exercise intolerance from other causes. Ref: J. Vet. Intern. Med. 2015; 29(3):940-945.

Answer 42

- Tracheal mucus, tracheal septum thickness and bronchial mucus were significantly increased in horses with severe inflammation BALs. - Tracheal mucus, tracheal septum thickness and bronchial mucus were correlated among themselves but not with upper airways scores. - BAL neutrophils percentage was correlated with tracheal mucus, bronchial mucus and had a weak negative correlation with pharyngitis. - Conclusion: lower airway endoscopy scores are reflective of lower airway inflammation; however, upper and lower airways are independent in terms of severity of inflammation. Therefore, observing upper airway inflammation is not an indication to test for lower airway inflammation. Ref: J. Vet. Intern. Med. 2011; 25(5):1118–1126

Answer 43

- Relative expressions of TNF-a/glyceraldehyde 3 phosphate dehydrogenase, IL-4/GAPDH and IFN-g/GAPDH were greater in horses with IAD compared with controls. - IL-4/GAPDH and IFN-g/GAPDH mRNA expression was inc in horses with inc metachromatic cell counts compared with horses with normal metachromatic cell counts. - Only the mRNA expression of IL-1b/GAPDH was inc with airway neutrophilia. - Conclusions: differences in gene expression were associated with the presence of IAD and with specific cell types present in airway secretions of SB racehorses. Ref: J. Vet. Intern. Med. 2011; 25(2):322–329.

Answer 44

- IL-5, IL-1b, IL-6, IL-8, and IL-10 mRNA expression was upregulated in the IAD-total group vs control group. - The IAD-Neutro group showed inc expression of IL-17, IL-8, and IL-5 and a dec expression of IL-4 vs IAD-Mast group. - Conclusion: cytokines from the Th2 family play a key role in IAD and a different pathophysiology may be involved in mast cell versus neutrophil BALF accumulation in IAD. Ref: J. Vet. Intern. Med. 2012; 26(1):153–161.

Answer 45

- N-butylscopolammonium bromide is a potent bronchodilator, reaching maximum effect 10 minutes after IV admin. This effect dissipates within 1h of drug admin. - Clinical score at 10 and 30 min after NBB admin was significantly lower than baseline and transpulmonary pressure was significantly lower at 10 mins. Ref: J. Vet. Intern. Med. 2012;26(6):1433–1438.

Answer 46

- Haptoglobin is a marker of both acute and chronic systemic inflammation in horses with RAO. - High concentrations of SAA indicate acute inflammation. - C-reactive protein concentrations are not significantly different in healthy horses and horses with RAO. Ref: J. Vet. Intern. Med. 2012;26(6):1419-1426.

Answer 47

No. Ref: J. Vet. Intern. Med. 2012;26(6):1427-1432.

Answer 48

- MAPK and PI3K pathways regulate neutrophil migration induced by BALF of horses with heaves. - Inhibition of multiple pathways might be required to completely abolish BALF-induced neutrophil migratory activity and possibly inflammation in heaves. Ref: J. Vet. Intern. Med. 2013;27(1):164-170.

Answer 49

Yes. Compared to those without signs of respiratory disease, those with occasional mucous nasal discharge and coughing developed signs of RAO more frequently. Ref: J. Vet. Intern. Med. 2014; 28(2):618–623.

Answer 50

- Yes, RAO in horses is associated with systemic oxidative stress. - A significant increase in the activities of GPx and SOD was detected in RAO-affected horses vs control animals. - There was no significant difference between groups in terms of the erythrocyte lysate activities of CAT, GR, or TBARs or the plasma concentration of TBARs. Ref: J. Vet. Intern. Med. 2014; 28(6):1845-1852.

Answer 51

Yes. Administration of treatment rather than placebo corresponded to a statistically significant decrease in respiratory effort, nasal discharge, tracheal secretion, and viscosity, AaDO2 and neutrophil percentage and an increase in arterial oxygen pressure. Ref: J. Vet. Intern. Med. 2015; 29(1):286–293.

Answer 52

- Clinical signs, lung function, plasma PUFA composition, and BALF cytology were evaluated in horses on a pelleted diet only vs pelleted diet + omega-3 PUFA supplement. - PUFA group had greater improvement in clinical signs (cough score improved 60%), lung function (respiratory effort decreased 48%), and BALF (neutrophils decreased from 23 to 9%) vs placebo (cough score improved 33%, respiratory effort decreased 27%, BALF neutrophils increased from 11 to 17%; P

Answer 53

Nasopharyngeal lavage analysed by a combination of real time PCR directly and after culture or, alternatively, real-time PCR directly on a nasopharyngeal lavage and a nasal/nasopharyngeal swab can identify S. equi in over 90% of acute strangles cases. Ref: J. Vet. Intern. Med. 2013; 27(3):542–547.

Answer 54

- Systematic review and meta-analysis of 31 studies comprising 88 trials. - In natural exposure trials, beef calves vaccinated with various antigen combinations had a significantly lower BRDC morbidity risk than did nonvaccinated control calves. - In trials evaluating BHV-1 and MLV BVDV vaccines in experimental challenge models, vaccinated calves had a lower BRDC morbidity risk than did control calves. - In experimental challenge trials evaluating MLV BRSV and PI3 vaccines, no significant difference in morbidity or mortality risk was found between vacc and control calves. - The literature provides data but does not provide sufficiently strong evidence to guide definitive recommendations for determining which virus components are necessary to include in a vaccination program for prevention or mitigation of BRDC in cattle. Ref: J. Am. Vet. Med. Assoc. 2015; 246(1):126-142.

Answer 55

- Pasteurella multocida, Mannheimia haemolytica, and Histophilus somni were isolated in 54, 17, and 12 calves (sample size 95), respectively. - Mycoplasma bovis was identified by PCR testing or culture in 19 calves, and 78 calves were found to be positive for Mycoplasma spp. - Bovine coronavirus was detected in 38 calves and bovine respiratory syncytial virus in 1. - Only the presence of M. bovis was associated with higher odds of clinical signs, lung consolidation, and lower average daily gain. Ref: J. Vet. Intern. Med. 2015; 29(1):381–387.

Answer 56

- Comparison of veterinary auscultation and CALA (using a CALA score ≥2 as a cut off) revealed a substantial agreement (kappa = 0.77). - CALA had relatively high Se (92.9%) and Sp (89.6%) for diagnosing BRD compared with pen checking. - Conclusions: CALA had good diagnostic accuracy (albeit with a relatively wide CI). Its use in feedlots could increase the proportion of cattle accurately diagnosed with BRD. Ref: J. Vet. Intern. Med. 2015; 29(4):1112-1116.

Answer 57

- M. haemolytica was recovered from 29% of cattle: 13.1% at arrival and 19.8% at second sampling. - Nearly half of cattle received antimicrobial drugs (AMDs) parenterally, mostly as metaphylactic treatment at arrival. - Individual parenteral AMD exposures were associated with decreased recovery of M. haemolytica, whereas exposure in penmates was associated with inc recovery. - Most isolates were pan-susceptible; AMD exposures were not associated with resistance to any single drug. - Multiply-resistant isolates were rare but AMD exposures in pen mates were associated with increased odds of recovering multiply-resistant M. haemolytica. - Conclusions: resistance generally was rare in M. haemolytica. Antimicrobial drug exposures in penmates increased the risk of isolating susceptible and multiply-resistant M. haemolytica, a finding that could be explained by contagious spread. Ref: J. Vet. Intern. Med. 2015; 29(2):705–713.

Answer 58

- Respiratory disease occurs frequently in cloned calves (22/25 calves in this study). - 19/22 required INO; 2 remained hypoxaemic despite INO. - 13/19 were weaned from INO after a median of 70h. - 9/22 required ventilatory support; 5 were discharged, 3 were euthanised and 1 died due to resp dz. - Necropsy findings: atelectasis, pulmonary congestion and alveolar damages. - The most frequent abnormality is hypoxemia because of V/Q mismatch. It is possible to successfully support these calves by INO and mechanical ventilation. Ref: J. Vet. Intern. Med. 2011; 25(2):373–379.

Answer 59

- Yes; in an examination of 106 pre-weaned calves. Each preweaned calf was clinically inspected using the Wisconsin calf respiratory scoring chart (CRSC), tx history noted, thoracic ultrasound and auscultation performed. - Se of auscultation to detect consolidation was 5.9% - Only 41.1% of calves with consolidated lungs had been treated previously by the producers. - Se of detection when adding CRSC and prev tx was 71.4%. - Thoracic ausc is of limited value in dx lung consolidation in calves. U/s assessment of the thorax could be a useful tool to assess BRD detection efficiency on dairy farms. Ref: J. Vet. Intern. Med. 2014; 28(1):234–242.

Answer 60

- Acute respiratory failure with pulmonary haemorrhage. Ref: J. Vet. Intern. Med. 2012; 26(3):684–687.

Answer 61

- M. bovis can be isolated in pure culture from the mammary gland of cows with mastitis and from the joints, tendon sheaths, or periarticular tissues of cattle with arthritis, tenosynovitis, or chronic pneumonia and polyarthritis syndrome (CPPS). - M. bovis is the predominant pathogen isolated from the middle ear of calves with otitis media. - Conflicting evidence re importance in BRDC; although M. bovis alone can cause natural and experimentally induced clinical disease, the presence of M. bovis does not always result in disease, and clinical disease does not appear necessary for the maintenance and dissemination of M. bovis in the cattle population. Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 62

- Mastitis: mycoplasma was identified in bulk tank milk samples in 7–20% of dairies sampled in US; likely underestimate true prevalence b/c mycoplasmas are shed intermittently and mastitic milk is withheld from bulk tanks. - Dairy calves: nasal prev data from >30y ago in California: 34% infected herds, 6% free herds. More recent studies: almost all calves in diseased herds become infected. - Beef cattle: prev in nonstressed calves is low (0–7%); conversely, prevalence is often high even in the absence of clinical disease for comingled calves, transported calves, or calves at a feedlot. - Necropsy studies indicate M. bovis can contribute substantially to morbidity and mortality in feedlot cattle. Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 63

- One report est costs to US beef industry of US$32m/yr as a result of loss of weight gain and carcass value, and US$108m/yr to US dairy industry due to mastitis. - Costs of mycoplasma dz include reduced production, drugs and labor for tx, death and culling losses, implementation of dx and control measures, and a portion of the cost of non-pathogen-specific preventive measures. - Animal welfare consequences, given that the associated dz is often chronic and poorly responsive to treatment. Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 64

- M. bovis is well adapted to colonization of mucosal surfaces, where it can persist without causing CSx. - URT mucosa is primary site of colonisation after URT exposure; mammary gland after intramammary exposure. - M. bovis can be isolated from multiple body sites during early infection, partic URT, mammary gland, conjunctiva and urogenital tract; bacteremia has been documented. - URT mucosa and the mammary gland are most important sites of persistence and shedding of M. bovis. - Many cattle shed for a few months or less but some can shed intermittently for many months or years --> maintenance of M. bovis within a herd and naive exposure. - Stressful events such as transportation, co-mingling, entry into a feedlot, and cold stress are associated with increased rates of nasal shedding of M. bovis. Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 65

- Intro of asympt infected animals is thought to be the primary means of M. bovis-free herds become infected. - Once present, M. bovis can be readily transmitted from infected to uninfected cattle. - M bovis is difficult to eliminate from multi-age facilities. - Traditionally regarded as a contagious mastitis pathogen, with udder-to-udder spread major means of transmission. - Whether URT transmission with internal dissemination to the mammary gland is important in the epidemiology of M. bovis mastitis has not been determined. - For young calves, ingestion of infected milk is an imp means of M. bovis transmission. However, other means of trans must also be important, as the dz can occur in calves that are fed milk replacer or pasteurized milk. - Congenital infections appear to occur infrequently. - M. bovis might be transmitted in respiratory secretions via aerosols, nose-to-nose contact, or indirectly via feed, water, housing, or other fomites. - Mycoplasmas are susceptible to desiccation and sunlight, but M. bovis can survive for long periods in protected environments with greatest survival in cool, humid conditions e.g. ponds, dirt, recycled sand bedding. Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 66

- In some studies but not others an assoc between BVDV infection and M. bovis has been observed. - Bacterial coinfections in M. bovis-assoc pneumonia and otitis media are extremely common e.g. M. haemolytica, H. somni (feedlot) and P. multocida (younger calves). Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 67

- Characteristics that enable it to colonise and persist on mucosal surfaces, to invade tissues, and to persist at sites of disease despite an aggressive immune response. - Molecules involved in adherence, antigenic variation, invasion, immunomodulation, biofilm formation, and production of toxic metabolites are likely important. - Mycoplasmas lack a cell wall, and exposed membrane proteins facilitate adherence to mucosal surfaces and form the primary interface with the host. - M. bovis has a large family of immunodominant variable surface lipoproteins; likely impart a vast capacity for antigenic variation in M. bovis populations that contributes to immune evasion and persistence. - After adherence, many mycoplasmas, including M. bovis, generate products such as phospholipases, hydrogen peroxide, and superoxide radicals which damage host cells. - M. bovis can also form biofilms in vitro that impart increased resistance to desiccation and heat stress. Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 68

- Strong assoc between FPT and inc risk and severity of BRD in calves. - However, the role of maternal immunity in protection against M. bovis-associated disease is unknown; no assoc b/w post-colostral serum antibody titres against M. bovis and pneumonia in 325 dairy calves. Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 69

- Innate IR are critical in the early phase of mycoplasma infections; alveolar macrophages v imp in early clearance of mycoplasmas from the lung, however inapprop activation of macro (TNF-a) --> excessive inflammatory response. - Activation of macro --> recruitment of neuts = prominent cell type in the lungs, middle ear, and joints of M. bovis infected calves; extent of neutrophil recruitment is directly correlated with the severity of mycoplasma disease. - Although bovine neutrophils are able to kill opsonized M. bovis, unopsonized M. bovis can adhere to neutrophils and inhibit respiratory burst activity. - Adaptive IR remain poorly defined. - Adaptive responses that are in place at the time of exposure can help control new infections e.g. prior M. bovis mastitis protects cows from dev severe mastitis. - Adaptive responses are often ineffective at eliminating est mycoplasma infections. - How mycoplasmas avoid clearance by the host is not well understood. However, mycoplasmas can induce a broad range of immunomodulatory events that might induce ineffective immune responses, and variation of surface antigens could help mycoplasmas to avoid clearance mediated by adaptive responses. - Experimental respiratory infection of calves with M. bovis usually elicits a strong humoral response characterized by high levels of serum IgG1 and very little IgG2 and local mucosal IgG and IgA responses. - M. bovis inoculation of the mammary gland results in serum IgG and local mucosal IgG and IgA. responses. - Humoral responses of naturally infected cattle are more variable but appear to be important in protection from M. bovis (IgG in serum and local immunoglobulins). Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 70

- Endemic subclinical dz to severe mastitis outbreaks. - Cows of any age or stage of lactation are affected, including prepubertal heifers and dry cows. - Classically more than one quarter is affected, drastic dec in milk prod, signs of systemic illness relatively mild. - Mammary gland might be swollen but usually not painful. - Secretions vary from mildly abnormal to gritty or purulent, and are sometimes brownish in colour. - Hx of mastitis that is resistant to tx w antibiotics common. - Return to production is possible but slow. - +/- signs of arthritis, synovitis. joint effusion, resp dz. Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 71

- Any age; dairy or beef. - Nonspecific incl fever, tachypnea, dyspnea, and dec appetite +/- nasal discharge and coughing. - Poor weight gain in chronically affected animals. - +/- signs of otitis media, arthritis, or both, in the same animal or in other animals in the herd. - CPPS (polyarthritis in assoc with chronic pneumonia), occurs in beef cattle several weeks after feedlot entry. Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 72

- Enzootic dz or outbreaks in dairy or beef calves; occurs sporadically in feedlot cattle. - Early/mild cases: calves remain alert with a good appetite --> fever and anorexia. - CSx due to ear pain and CN VII deficitis: ear droop, ptosis, nystagmus, circling, falling, vestibular ataxia, head shaking and scratching or rubbing ears. - Epiphora/exposure keratitis secondary to eyelid paresis. - Clinical signs can be unilateral or bilateral. - Purulent aural discharge if the tymp memb has ruptured. - Concurrent pneumonia, arthritis, or both are common. - In advanced otitis media-interna, meningitis can develop. - Spontaneous regurg, loss of pharyngeal tone, dysphagia have also been reported. Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 73

- Cases tend to be sporadic and are often concurrent with cases of pneumonia or mastitis, although outbreaks have been reported in calves and dairy cows. - CPPS is described in feedlot cattle. - CSx incl acute non-weightbearing lameness with joint swelling, pain, and heat on palpation +/- fever, anorexia. - Involvement of tendon sheaths and periarticular soft tissues is common. - Large rotator joints (hip, stifle, hock, shoulder, elbow, and carpal) are most commonly affected. - Poor response to treatment is a common feature. Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 74

1. Keratoconjunctivitis. M. bovis can be isolated from the conjunctiva of healthy and diseased cattle; involvement in infectious keratoconjunctivitis (IKC) is seldom reported. 2. Meningitis. can occur as complication of otitis media-interna; has been reported with disseminated septic dz. 3. Decubital abscesses. Over the brisket in In 1 report of 50 calves; some had concurrent M. bovis-assoc pneumonia. 4. Cardiac Disease. M. bovis was ID concurrently w H. somni in the hearts of 4/92 feeder calves dying from myocarditis. One report of chronic active fibrinopurulent endocarditis. 5. Genital Disorders. Little evidence to support an important role for M. bovis in naturally occurring bovine repro dz. Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 75

- Serum AB-ELISA: indv titres poorly correlated with infection or dz; on a group level, seroconversion or high titres are predictive of active M. bovis infection. - Intermittent and low-level shedding, uneven distrib of M. bovis throughout diseased tissue, suboptimal sample handling or culture cond, and the presence of mycoplasma inhibitors in samples likely contrib to low sensitivity. - Sensitivity of milk culture for diagnosis of mycoplasma intramammary infection low in bulk milk or asymptomatic cows but higher in cows with clinical mastitis. - Realtime PCR systems with high Se and Sp have been described for detection of M. bovis in clinical samples. - M. bovis can be detected in situ by IHC on formalin fixed, paraffin embedded tissues or IFAT frozen lung tissue. - TTW/BAL better than nasal swabs for pneumonia, although isolation of M. bovis not well correlated w dz. - Joint/tendon sheath aspirates can be submitted. - Rad/CT/US can aid dx of otitis media/interna. Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 76

- Definitive dx: demonstration of M. bovis in affected tissues by IHC or by culture, PCR, or sELISA - Pneumonia: multiple necrotic foci filled with dry yellow to white caseous material, raised, 2mm-several cm diam; interlobular septae can contain linear necrotic lesions; extensive fibrosis common; acute fibrinous to chronic fibrosing pleuritis occurs in some cases. - Histo: subacute to chronic bronchopneumonia that can be suppurative and is usually necrotising. - Mastitis: mild to severe fibrinosuppurative to caseonecrotic mastitis. - Otitis media: tympanic bullae contain suppurative to caseous exudate and have often undergone extensive osteolysis. - Arthritis: nonodorous fibrinous to caseous exudate accompanied by fibrosis. Affected periarticular tissues contain foci of caseous necrosis, linear necrotic lesions, and extensive fibrosis. Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 77

- No. - Cows that spontaneously resolve clinical mastitis or become culture negative often remain intermittent, subclinical shedders; regard as permanently infected. Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 78

- Because mycoplasmas lack a cell wall, the b-lactam antimicrobials are not effective against them. - Similarly, they do not synth folic acid and are therefore intrinsically resistant to sulfonamides. - Mycoplasmas are generally susc to drugs that interfere with protein (tetracyclines, macrolides, linosamides, and florfenicol) or DNA (fluoroquinolones) synthesis. However, M. bovis is resistant to erythromycin Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 79

- Metaphylactic use of antimicrobials is probably justified when high levels of morbidity and mortality because of M. bovis-associated disease are being sustained or can be expected in high-risk cattle, although M. bovis-specific efficacy data and economic analyses are needed. - E.g. tulathromycin, florfenicol, tilmicosin. Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 80

- Despite several vaccines being on the market, attempts to vaccinate cattle against M. bovis-associated disease have been unrewarding in the field. Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 81

- Maintain a closed herd or, if that is not possible, screen and quarantine purchased animals. - Examine bulk tank culture history of the herd of origin when purchasing heifers or adults or sample bulk tank at least 3 times spaced 3–4 days apart. - Examine calf-health records to determine if M. bovis-assoc dz e.g. otitis media have been observed. - When purchasing lactating cows, milk samples should be submitted for mycoplasma detection (culture, PCR, sELISA), keeping in mind the low Se of a single sample. - Testing purchased dry cows, purchased heifers, and heifers raised offsite at calving and isolating them until results are obtained has been recommended. - Serology has been used to help identify uninfected groups of cattle before purchase. Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 82

- Bulk tank testing (culture, PCR, sELISA) should be performed at least monthly, with more frequent sampling indicated for large herds, herds undergoing expansion, or when managing a mycoplasma problem. - Sampling of clinical mastitis cases, high somatic cell count cows, and cows and heifers at calving. - Mastitis records, incl response to tx, should be monitored. - Small herd or herd trying to maintain free status: eliminate through aggressive surveillance and culling infected cows. - For expansion herds or dairies where a large proportion of the lactating herd is infected, eradication of M. bovis might not be appropriate or economical. - Attempted elimination of all adult cows with intramammary mycoplasma infections remains the strongly recommended course of action. - Strict segregation of infected cows has been used effectively to limit new infections. - Strict milking parlor hygiene is recommended to reduce udder-to-udder transmission of M. bovis. - Bedding found to be mycoplasma positive, usually recycled bedding processed on the farm, should not be used to bed dairy animals of any age. Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 83

- Surveillance for M. bovis in calf facilities should incl monitoring of health records and submission of samples from suspect cases for diagnostic testing. - M. bovis exposure via infected milk can be eliminated by pasteurization or by feeding milk replacer. - Exposure to infected colostrum could be reduced by pasteurization, by not pooling colostrum, and by not feeding colostrum from cows known to be infected. - Exposure to airborne M. bovis could be reduced by good ventilation, low-stocking density, segregating sick calves. - All-in, all-out practices or segregation of age groups might also limit transmission of M. bovis in multiage facilities. - Removing fence-line contact with other cattle and limiting the time the calf spends in the maternity area will also reduce the potential for exposure. - Proper sanitization of buckets, housing, and other equipment between uses, wearing gloves, and handling sick calves last could reduce fomite-mediated transmission. Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 84

- Recommendations focus on maximising respiratory system health and immune function rather than M. bovis-specific measures. - Strategic antibiotic treatment of high-risk animals on arrival or during an outbreak of BRD might be useful in reducing the incidence of mycoplasma disease. - Segregating affected cattle and keeping the hospital pen separate from new arrivals could reduce exposure. - Using appropriate hygiene measures for handling sick cattle (use separate equipment or personnel or clean equipment among animals, feed last, etc) could reduce the chances of fomite-mediated M. bovis transmission. Ref: ACVIM 2011 Consensus Statement - M. bovis.

Answer 85

- Characterised by abrupt onset of fever followed by URT catarrh, as evidenced by mucopurulent nasal discharge and acute swelling with subsequent abscess formation in submandibular and retropharyngeal lymph nodes. - Older horses often exhibit a mild form of the dz charac by nasal discharge, small abscesses, and rapid resolution; younger horses are more likely to develop severe LN abscessation that subsequently opens and drains. - Pharyngitis --> dysphagia, anorexia, extended neck. - Depression, listlessness. - Pharyngitis, laryngitis, and rhinitis may occur --> bilateral nasal discharge - serous --> mucopurulent --> purulent. - Nasal and ocular mucosa may become hyperemic, and there may be purulent ocular discharge. - Lymphadenopathy may cause: external drainage, severe dyspnea, stridor, and dysphagia, marked swelling of the eyelids, severe tracheal compression, asphyxia and death. - Coughing not significant feature in many cases. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 86

- S. equi enters via the mouth or nose and attaches to cells in the crypt of the lingual and palatine tonsils and to the follicular-assoc epi of the pharyngeal and tubal tonsils. - Translocation occurs in a few hours to the mandibular and suprapharyngeal lymph nodes. - Complement-derived chemotactic factors generated after interaction of complement with bacterial peptidoglycan attract large numbers of PLNs. - Failure of neuts to phagocytose and kill the strep appears to be due to a combination of the HA capsule, antiphagocytic SeM protein, Mac protein, and other undetermined antiphagocytic factors released by the org. - Final disposal of bacteria is dependent on lysis of the abscess capsule and evacuation of its contents. - Streptolysin S and streptokinase may also contribute to abscess dev and lysis by damaging cell membranes and activating the proteolytic properties of plasminogen. - Fever occurs 3-14 days after exposure and is assoc with release of the pyrogenic mitogens SePE-H and I. - The larger the intranasal inoculum of cultured S equi, the shorter the incubation period and the more severe the disease that results. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 87

- Spread may be hematogenous or via lymphatic channels channels, which results in abscesses in lymph nodes and other organs of the thorax and abdomen. Metastasis to the brain has also been recorded. - Bacteraemia occurs on days 6 to 12 in horses inoculated intranasally with virulent S equi. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 88

- Nasal shedding: usually begins 2-3d days after onset of fever and persists for 2 to 3 weeks in most animals. - Some animals never shed. - Some shed for a long time due to GP infection. - Systemic and mucosal IR are evident 2-3wk after infection and coincide with mucosal clearance. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 89

- Systemic and mucosal IR are evident 2-3wk after infection and coincide with mucosal clearance. - ~75% of horses develop a solid, enduring immunity to strangles after recovery from the dz (lasting >5yr). - A small proportion become susceptible to dz w/in months. - Strong serum IgGb responses to surface-exposed proteins, incl SeM, Se44.2, Se46.8, Se45.5, and Se42.0, are produced during convalescence. - SeM-specific IgGa is induced during and shortly after S equi infection. Strong SeM-specific mucosal IgA and IgGb responses occur during acute and convalescent phases. - Milk from mares that have recovered from strangles contains IgGb and IgA with specificities similar to those found in nasopharyngeal mucus of convalescent horses. - Colostral antibodies recirculate to the nasopharyngeal mucosa --> resistance to S equi infection until weaning. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 90

- Purulent discharges from horses with active and recovering strangles are an important source of new S equi infections among susceptible horses. - A recovered horse may be a potential source of infection for at least 6 weeks after CSx have resolved. - Long-term, subclinical S equi carriers (10% cases) w GP empyema may shed intermittently for months to years. - Direct transfer: nose-to-nose transmission. - Indirect transfer: sharing of contam housing, water sources, feed or feeding utensils, twitches, tack, clothing and equipment of handlers, farriers, vets etc. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 91

- Currently there is a lack of field-based proof for prolonged environmental persistence of S equi. - One laboratory- based study documented that the organism survived for 63 days on wood at 28C and for 48 days on glass or wood at 20C. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 92

- Culture: of nasal washes > swabs, or pus aspirated from abscesses remains the ‘‘gold standard’’; plate speciments on Columbia CNA agar with 5% sheep or horse blood added; unlike S equi, S zooepidemicus ferments sorbitol and lactose, both are beta haemolytic. - PCR: designed to detect DNA sequence of SeM, the gene for the antiphagocytic M protein of S equi; 3x more sens than culture and same day return but presumptive until confirmed with culture. PCR is useful to: - Detect asymptomatic carriers. - Establish S equi infection status prior to transport. - Establish S equi infection status following transport prior to commingling. - Determine the success of elimination of S equi from the guttural pouch. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 93

- Does not distinguish between vaccine and infection. - AB titres peak 5wk post-infection; remain high for 6mo. - Horses at risk for dev of purpura are hyperresponders and make very strong antibody responses. Such animals, with titers in excess of 1 : 3200, should never be vaccinated. - Negative: no exposure or exposure w/in 7 days. - Weak pos (1:200-1:400): very recent or residual antibody from exposure to S equi or vaccine in the remote past. - Mod pos (1:800-1:1600): 2-3 weeks after exposure or where the infection occurred 6 mo to 2 yr previously. - High pos (1:3200-1:6400): 4-2 weeks after infection or 1-2 weeks following inj vacc or 2-4 wks after intranasal vacc. Vaccination is contraindicated if antibody 1 : 1,600 or more. - Very high pos (>1:12800): often found in horses with a metastatic abscess or purpura hemorrhagica. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 94

1. Extract vaccines: - IM or SC. - Elicit serum antibody responses 7-10d later. - Naive horses and foals: 2-3 doses q2wk. - Boosters years; one month prior to foaling. - Horses that have had strangles w/in the previous year, with signs of strangles or titres >1:1600 should not be vacc. 2. Attenuated live intranasal vaccine: - Schedule: 2 doses at 2-3wk intervals; annual boosters. - Should only be admin to healthy, nonfebrile animals free of nasal discharges. - Live vaccine should not be used during an outbreak except in horses with no known contact with infected or exposed animals. - No data are available about colostral antibody levels following admin of intranasal vaccine to broodmares. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 95

- Stop all horse movements on/off the affected premises. - Implement hygiene measures immediately. - Segregate strangles cases and contacts. - Take rectal temp at least once daily to detect, promptly segregate, and possibly treat new cases. - Screen all convalescing cases following clinical recovery and their contacts via swab or lavage of the nasopharynx. - Collect swabs/lavage fluid at weekly intervals following recovery over several weeks and test for S equi by conventional culture and PCR. - Because PCR can detect dead as well as living bacteria, pos PCR results are regarded as provisional --> URT and GP endoscopy; collect lavage samples for PCR/culture. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 96

- Repeated lavages of pus-filled pouches via rigid or indwelling catheters using isotonic saline or polyionic fluid. - Topical and systemic penicillin (topical gelatin benz pen). - Topical installation of 20% (w/v) acetylcysteine solution; denaturing and solubilizing activity by disrupting disulphide bonds in mucoprotein molecules, thus reducing mucus viscosity and so theoretically facilitating natural drainage. - Chondroid removal using a memory-helical polyp retrieval basket through the biopsy channel of the endoscope. - Scarring of the pharyngeal openings of the GPs may preclude natural drainage and endoscopic access to the GPs --> Sx or endoscopically guided laser treatments to break down scar tissue and allow access to the pouches. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 97

- During an outbreak, immediate antibiotic therapy (3-5d) of new cases in early acute phase with fever and depression may be curative and may prevent focal abscessation. - Antibiotic tx will inhibit synth of protective antigens and the dev of protective immunity will not be stim, so the horses will be highly susceptible to reinfection once tx is discont if the horse remains exposed to infected horses. - No evidence that early tx increases the risk of bacteraemia, septicaemia and metastatic abscessation. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 98

- Antibiotic therapy is contradicted UNLESS horse is febrile, depressed, anorexic, and especially manifesting dyspnea as result of partial upper airway obstruction. - Therapy should be directed toward enhancing maturation and drainage of the abscesses. - Topical treatments e.g. icthamol or a hot pack. - Surgical drainage is sometimes indicated if abscesses do not rupture spontaneously; however, it is critical to wait until the abscess has matured and thinned out ventrally. - Daily flushing of the open abscess with a 3–5% povidone iodine solution until the discharge ceases. - NSAIDs may improve the horse’s demeanor by reducing fever, pain, and inflammatory swelling at the site of the abscesses and may encourage eating and drinking. - Rarely: IVFT, feeding via NGT, tracheostomy. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 99

- Penicillin. - Anecdotally TMPS improves S. equi infection. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 100

- Overall complication rate is approximately 20%. - In a study of 74 horses, 20% had complications of which 40% died vs. overall case fatality rate of 8%. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 101

- Most common: lung (suppurative bronchopneumonia), LNs, mesentery, liver, spleen, kidneys, and brain. - Extension of infection to sinuses or guttural pouches. - Also reported: myocarditis, endocarditis, panophthalmitis, periorbital abscesses, ulcerative keratitis, paravertebral abscesses, septic arthritis, and tenosynovitis. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 102

- Varies depending on the site of infection and whether there are concurrent signs of classic strangles. - Bronchopneumonia, GP empyema, or sinusitis --> culture. - Internal abscesses: - - Hx of exposure to S equi or low-grade fever responsive to penicillin. - - Laboratory results consistent with chronic infection e.g. elevated SeM-specific antibody titers, anemia, hyperfibrinogenemia, and hyperglobulinemia. - Mesenteric abscesses may be accompanied by an immune ascites with elevated SeM-specific antibody in ascitic fluid. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 103

Long-term antimicrobial therapy, and appropriate local treatment or drainage of abscesses if possible. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 104

- PH is an aseptic necrotizing vasculitis charac primarily by oedema and petechial or ecchymotic haemorrhage. - Appears to be a vasculitis caused by the deposition of immune complexes in blood vessel walls. - Commonly assoc w S. equi infection but other aetiologies also possible. - A pre-existing high serum antibody titer to S equi antigens may predispose horses to the development of purpura. - Studies have suggested an association between the development of purpura and antibodies of the IgA isotype. - The immunologic basis for the high conc of IgA and low conc of IgG during the acute stages of purpura is not understood; proposed explanations incl uncontrolled expansion of B cell populations that prod IgA, failure of IgA removal mechanisms, delayed, defective or suppressed prod of IgG, and neutralisation or excess utilisation of IgG. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 105

- Vary from mild and transient to severe, fatal dz. - S/C oedema, most frequently involving the head, limbs, and/or trunk, and petechiation and ecchymoses of the MM. - Severe edema may result in oozing from the skin surfaces, and sloughing of the skin may occur. - Vasculitis may affect other sites e.g. GIT, lungs, and muscle --> colic, resp prob, muscle soreness. - Skin histo: leukocytoclastic vasculitis - Isolation of the organism and demonstration of elevated IgA and IgG titers to S equi are also supportive. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 106

- Corticosteroids are the primary treatment for purpura. - Antibiotic therapy. - NSAIDs in some cases. - Supportive care incl IVFT, hydrotherapy, bandaging. - 1/4 and 3/22 cases died. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 107

- Likely a manifestation of purpura hemorrhagica. - Severe vasculopathy characterized by infarction of skeletal muscle, skin, GIT and lungs. - Present with muscle stiffness, lameness and elevations in muscle enzymes in conjunction with other signs, such as abdominal pain and subcutaneous swelling. - Histo: acute coagulative necrosis of muscle with infarctions +/- pulmonary hemorrhage or GI infarctions. - Px guarded. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 108

- ID is some QH, some had PSSM, others no underlying myopathy. - CSx: malaise, rapid progressive atrophy of the epaxial and gluteal muscles. - Muscle enzymes were elevated. - Muscle biopsies revealed chronic active rhabdomyolysis with regeneration, prominent macrophage infiltration, atrophy of fast-twitch fibers, and lymphocytic vasculitis --> fibrosis around blood vessels over time. - May be an immune response resulting from similarities between the amino acid sequence of an S equi protein and equine myosin in certain horses. - Tx: corticosteroids; ABs if signs of concurrent infection. - Muscle mass may return to normal with tx. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 109

Streptococcal antigens have been suggested as a trigger for development of myocarditis and proliferative glomerulonephritis. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 110

- Has been reported in broodmares with strangles. - Thought to be secondary to the fever, anorexia, and lethargy associated with infection not active infection of the mammary gland. Ref: ACVIM 2005 Consensus Statement - Strep. equi.

Answer 111

1. Inclusion criteria: - Poor performance, exercise intolerance, or coughing, with or without excess tracheal mucus. - Nonseptic inflammation detected by cytologic examination of BALF or pulmonary dysfunction based on evidence of lower airway obstruction, airway hyper-responsiveness, or impaired blood gas exchange at rest or during exercise. 2. Exclusion criteria: - Evidence of systemic signs of infection (fever, hematologic abnormalities compatible with infection). - Increased respiratory efforts at rest (ie, heaves). Ref: ACVIM 2007 Consensus Statement - IAD.

Answer 112

- CSx: chronic, intermittent cough, increased mucoid airway secretions, and decreased performance. - Cough can occur at rest or during exercise; absence of cough does not rule out IAD. - Multiple specks of mucus along the length of the trachea, a pool of mucus at the thoracic inlet, or a continuous stream of variable width. - Relationship between nasal discharge and IAD as defined in this consensus is currently unknown. - Thoracic auscultation usually WNL, but some horses can exhibit increased breath sounds or subtle wheezes, particularly during rebreathing manoeuvres. - IAD in racehorses --> poor racing performance, delayed recovery of RR after exercise, exaggerated resp effort during exercise. Ref: ACVIM 2007 Consensus Statement - IAD.

Answer 113

- Noninfectious agents are likely to be central to the development of IAD. - Introduction of horses to a stable is a risk factor for IAD = high dust enviro; dust may include a variety of organic and inorganic particles including endotoxin, (1R3)-b-D-glucan, ultrafine particles, micro-organisms, mite debris, vegetative material, inorganic dusts, and noxious gases. - The presence of high eosinophil or mast cell counts in BALF from some horses with IAD suggests that aeroallergens might contribute to the dev of this syndrome. - Contribution of enviro pollutants, cold, dry environments, and infectious agents to dev of IAD is unknown. Ref: ACVIM 2007 Consensus Statement - IAD.

Answer 114

- TTW cytology is deemed insufficient for the diagnosis of IAD as defined here in the absence of BALF cytology or pulmonary function testing. - BALF: most commonly BALF cytologic profile in IAD is inc INCC w mild neutrophilia, lymphocytosis, and monocytosis; two other profiles mainly in young horses w IAD are charac by inc mast cell and eosinophil counts. Ref: ACVIM 2007 Consensus Statement - IAD.

Answer 115

- Supportive of the diagnosis of IAD and exclusionary of alternative dx but insufficient for diagnosis of IAD. - In one study, a bronchial pattern was observed more frequently in horses with IAD, radiographic changes were not statistically assoc with abnormal BALF cytology or pulmonary function tests. Ref: ACVIM 2007 Consensus Statement - IAD.

Answer 116

- Several studies have documented neg impact of IAD on lung function both at rest and during exercise. - Gas exchange is impaired during exercise in horses w IAD. - Lung function tests such as forced expiration and forced oscillation mechanics indicate that horses with IAD have airway obstruction. - Airway hyper-responsiveness is a prominent feature of horses with IAD. Ref: ACVIM 2007 Consensus Statement - IAD.

Answer 117

- RAO. - Upper airway disease. - Bronchopneumonia/pleuropneumonia. - Viral respiratory infections. - EIPH. - Thoracic neoplasia. - Lungworm. Ref: ACVIM 2007 Consensus Statement - IAD.

Answer 118

- Environmental change. - Control of airway inflammation: systemic or inhaled corticosteroids, inhaled mast cell stabilisers. - Bronchodilators: probably most efficacious when combined with anti-inflammatory therapy, because the underlying mechanism of this disease is most likely related to persistent airway inflammation. Ref: ACVIM 2007 Consensus Statement - IAD.

Answer 119

- Reduce exposure of the horse’s airways to respirable particles by: i) Use feedstuff and bedding that generate low dust and endotoxin concentrations. ii) Inc removal of airborne particles and noxious gases by improving ventilation in the building. - Changing bedding material from straw to cardboard can cut respirable dust concentrations in half and reduce mould concentration to negligible concentrations. - Replacing hay feed and straw bedding by wood shaving bedding and a complete pelleted diet was shown to decrease the respirable dust burden by 97%. - Low-dust beddings are shredded paper and peat moss. - The activity in the barn also affects dust exposure with peak concentrations occurring during the day especially at the time of feeding and cleaning stalls. - Different feed and bedding materials may have variable conc of endotoxin, which can directly irritate airways. Ref: ACVIM 2007 Consensus Statement - IAD.

Answer 120

- Family: Arteriviridae. - Genus: Arterivirus. - Enveloped RNA virus. - Species specific, highly resistant to cold temps, and highly variable because of its high mutation rate and potential for recombination. Ref: J. Am. Vet. Med. Assoc. 2015; 246(12):1304-1317.

Answer 121

- Routes of shedding include saliva, nasal secretions, semen, urine, feces, and mammary gland secretions. - Transmission may occur through multiple common routes, including intranasally, orally or intramuscularly. - Prolonged infection is a hallmark of PRRSV, up to 200d. - Vaccination appears to reduce shedding. - PRRSV is highly susceptible to inactivation by heat, common disinfectants and drying. - At temperatures between –20°C and –80°C, PRRSV can be stable for months to years, but infectivity is quickly lost when pH of a solution is 7.5. - It is assumed that pigs with maternal immunity are not likely to have that immunity wane over the suckling period. - Pigs born to infectious sows are assumed to be infectious. - In one model herd closure together with acclimatisation of gilts and repeated mass immunisation was the scenario that resulted in the highest number of iterations that achieved stable status. Ref: J. Am. Vet. Med. Assoc. 2015; 246(12):1304-1317.

Answer 122

- Live pigs and semen: -- Testing serum with PCR assays is more sensitive and detects PRRSV in infected boars earlier than does testing semen with PCR assays NOT pooled. -- Practices to reduce risks assoc w entry of gilts include purchasing gilts from PRRSV-neg sources and isolation of purchased gilts prior to entry into a herd. -- Acclimatisation of gilts to provide immunity to PRRSV by intentional exposure to wild-type PRRSV or vaccination followed by a period sufficient to ensure they are no longer shedding virus reduces spread of the virus. - Vehicles: an amount of live virus sufficient to infect PRRSV-neg pigs can remain in unwashed trailers transporting infected weaned pigs in faeces for 120h at 4°C. Risk in reduced by a comb of disinfection and drying. - People: methods to reduce risks assoc w drivers incl use of disposable plastic boots, boot baths w bleach, changing boots and coveralls, washing hands etc. - Tools, equipment, and supplies: mechanical trans of PRRSV via fomites has been confirmed, with a higher frequency of transmission in cold weather. - Food and water: conflicting reports of transmission from infected pork to live pigs. - Non-swine animals and insects: houseflies and mosquitoes are vectors, not stable flies in one study; insect screens superior to pyrethrins for reducing bites; results looking at non-swine animals as reservoir are inconsistent. - Air: aerosol tranmission occurs; amount may vary w isolate; air filters reduce risk of transmission. Ref: J. Am. Vet. Med. Assoc. 2015; 246(12):1304-1317.

Answer 123

- Classification as per the AASV scheme from positive unstable to negative. - Control of PRRS starts in the sow herd, with the intent of weaning pigs with a low prevalence (ideally zero) of PRRSV. - 2 fundamental strategies to accomplish this: i) Maintaining a uniform level of immunity through vaccination, strategic exposure to live virus from the herd, or both; based on the rationale that some immunity in a herd is better than no immunity. ii) Goal of eliminating PRRSV from the sow herd via depopulation, partial depopulation, test and removal, and herd closure. Ref: J. Am. Vet. Med. Assoc. 2015; 246(12):1304-1317.

Answer 124

- Infection with PRRSV does not result in pathognomonic clinical signs. - Both serum and oral fluid specimens are suitable for nucleic acid (PCR assay) or antibody-based testing, but each has advantages and disadvantages. - Detection of nucleic acid reflects current circulation of pathogens. - Antibodies are abundant in serum and can be readily detected in oral fluid; cost of antibody assays is substantially less than that of PCR-based assays. - In contrast to nucleic acids, antibodies provide a prolonged window of detection because they reflect both recent and past exposure history. - At the farm level, antibody assays are compatible with continuous monitoring of population immune status by use of control charts. - Point-in-time detection of pathogens or nucleic acid may be useful for pathogen charac or vaccine development. Ref: J. Am. Vet. Med. Assoc. 2015; 246(12):1304-1317.