Infectious Diseases Flashcards
What is the common breed associated with Babesia canis and Babesia gibsoni infection, respectively?
Babesia canis: Greyhound
Babesia gibsoni: Pit Bull Terrier
Babesia gibsoni clinical signs and treatment protocol vs treatment for B. vogeli
Mainly hemolysis but also thrombocytopenia
Treatment with atovaquone and azithromycin
B.vogeli treated with imidocarb
What are the two common virus for feline upper respiratory tract diseases?
Feline Herpesvirus 1
Feline Calicivirus
True or False: For acute feline upper respiratory tract diseases, antibiotic is not recommended immediately. If patient declines with supportive care after 10 days, the first-line antibiotics is doxycycline or ampicillin.
True
True or False: 𝜷-lactam antibiotic is the first-line antibiotic for Bordetella bronchiseptica.
False
Not effective
True or False: For cats with chronic URI, If Pseudomonas aeruginosa is isolated in pure or nearly pure culture and believed to be the cause of a secondary infection, extensive flushing of the nasal cavity under anesthesia should be performed to remove loculated secretions.
True
If a cat with diagnosed URI develops mucopurulent discharge after treatment, what is recommended according to the ACVIM guidelines?
Restart the last effective antibiotic
If the treatment is ineffective in 48 hours, switch to another drug in the same class or different drug class
List 5 viruses that have been associated with CIRDC.
Canine adenovirus 2
Canine parainfluenza virus
Canine influenza virus
Canine distemper virus
Canine herpesvirus
Canine pneumovirus
Canine respiratory coronavirus
What is the first-line empirical antibiotics for CIRDC?
Doxycycline
What is the recommended treatment duration for bacterial bornchitis?
If a positive response is obtained in the first 7–10 days, treatment should be continued to 1 week past resolution of clinical signs.
List 3 antibiotics that are effective to Mycoplasma spp
Enrofloxacin
Doxycycline
Azithromycin
According to the ACVIM guidelines, what is the recommended approach for canine and feline aspiration pneumonia?
If the dog or cat is acutely affected and has no evidence of systemic sepsis, the Working Group believes that either no treatment or parenteral administration of a beta-lactam antimicrobial like ampicillin, ampicillin-sulbactam, or the first-generation cephalosporin cefazolin might be sufficient
According to the ACVIM guidelines, what is the recommended antibiotic duration for bacterial pneumonia?
Re-evaluated in 10-14 days
What type of bacteria is most common in canine pyothorax?
Mixed anaerobes
Prevotella spp., Peptostreptococcus spp., Propionibacterium acnes, Clostridium spp., Bacteroides spp., Fusobacterium spp.
What type of bacteria is most common in feline pyothorax?
oropharyngeal anaerobes
Which breed is predisposed to systemic aspergillosis?
GSD
Forms of aspergillosis
- sino-nasal
- sino-orbital
- invasive
Which antifungal is recommended for systemic aspergillosis?
Posaconazole
(indefinite treatment likely needed)
What is the proposed mechanism for tick paralysis?
Holocyclotoxin
- Impair ACh release at the NMJ by blocking Ca2+ influx at the axon terminal
- impairs ACh at autonomic synapses, resulting in autonomic imbalance (predominantly sympathetic overdrive)
Is Clostridium botulinum a gram positive or gram negative anaerobic bacteria?
Gram positive
Which virus can cause corneal ulceration and keratitis, FHV-1 or FCV?
FHV-1
What type of virus is canine distemper virus?
Enveloped RNA virus
What type of virus are feline herpesvirus and feline calicivirus?
FHV-1: enveloped DNA virus
FCV: non-enveloped RNA virus
In feline panleukopenia, what are the three poor prognostic indicators?
Leukopenia
Hypokalemia
Hypoalbuminemia
Where is canine distemper virus first infected in the body?
Monocytes within lymphoid tissue in the upper respiratory tract and tonsil
What type of virus is FIP virus?
Enveloped RNA virus
How long does it take for dogs with parvoviral infection to show clinical signs after infection?
4-10 days
What findings in blood work is a positive prognostic indicators in paroviral infection?
- Lack of lymphopenia on admission, at 24 and 48 hours post-admission (not leukopenia)
- Presence of left shift
- Lower total cholesterol
- High-density lipoprotein cholesterol
When do patients with parvoviral infection start to shed virus?
3-4 days after exposure
In canine parvoviral infection, monitoring which WBC parameter may aid in the evaluation of bone marrow response?
Monocyte count
For puppies who get colostrum with parvo antibodies, how long will the protection last?
12-20 weeks
Parvo tests
PCR in faeces gold standard
POC Elisa poor sensitivity but high specificity
Poor prognostic indicators for parvo
Hypovolemia, low TP, high cortisol, low T4, lymphocytes <1000/ul, hypoalbuminemia
What kind of drug pH will help to trap the drug in the milk?
Weak base
- Milk is weak acid
Name the three class of drugs that can be used to treat mastitis and are safe for the neonates.
Penicillin
Cephalosporins
Macrolides
In blastomycosis, what antigen cause the cell-mediated immune response?
Blastomyces adhesion 1 (BAD-1) antigen
Also Galactomannan used for antigen test but shared with Histoplasma
What is the most common clinical signs for blastomycosis?
Respiratory signs
Where can you collect sample for histopasma cytology?
Rectal mucosal scraping
Lymph node aspirate
Dermal nodule cytology
Fluid analysis
Bone marrow
Liver, splenic aspirate
BAL
- Most common form is disseminated form
What is the most and second most common fungal infection in cats?
1) Cryptococcosis
2) Histoplasmosis
True or False: Compared to dogs, cats are relatively resistant to coccidioidomycosis.
True
True or False: For dogs with coccidioidomycosis, about 65% has concurrent bone involvement.
True
What are the 4 types of necrotizing soft tissue infection?
Type I: polymicrobial (typical of humans with DM)
Type II: monomicrobial with G+
Type III: associated with G- (i.e. marine-related organisms) or gas producing bacteria (i.e. Clostridium)
Type IV: associated with fungal infection
Fill out the blank:
The minimum inhibitory concentration (MIC) is defined as “the lowest concentration of an antibiotic that will __________ of a given bacteria.”
inhibit the visible growth
What is the pathogen of lyme disease?
Borrelia burgdorferi
What is the vector for Borrelia?
Ixodes spp.
Same as for Anaplasma phagocytophylus
Diagnosis of Lyme
Borrelia express OspA when in the tick, during blood meal change temperature and expresses OspC. Once in the host predominant expression of C6.
* 4DX tests for C6 antibodies
* Lyme quant6 for quantitative C6 titers
* Multiples quantitative abx for OspA, OspC and OspF (vaccines contain OspA and OspC so false negative possible)
* Accuplex detects C6 antibodies 2weeks earlier than 4Dx
If 4DX positive for Borrelia and non-symptomatic…
Check UPC and if negative repeat after 2-3 weeks.
If still negative abx therapy (dpxy 10mg/kg SID for 4 weeks) optional.
What is the immunosuppressive drug of choice for lyme nephritis? When should it be given?
Mycophenolate +/- corticosteroids
When immune-complex glomerulonephritis (ICGN) is confirmed via biopsy or if patient deteriorates rapidly despite other medical management
Which species of Lepto are most commonly involved in canine disease?
- L.interrogans: Icterohemorrhagie
Canicola
Pomona
Australis
Bratislava - L.Kirshneri
Gryppotyphosa
Negative prognostic factors for Lepto
- hyperbilirubinemia
- hypocoagulability
vs normalisation of CRP good prognostic factor
Lepto case definition
- probable
clinical criteria + 1 supportive lab result - confirmed
clinical criteria + 1 definitive lab result
Supportive vs definitive lab criteria for Lepto
Supportive:
* MAT titer >800 in 1 serum specimen
* IgM positive in acute phase
* visualisation of spirochetes
Definitive
* 4x increase in MAT
* PCR positive in blood
* isolation in culture
POC test for Lepto
- Idexx SNAP (IgG): sens and spec approx 70% (>10d)
- Zoetis Witness (IgM): more sensitive and more specific (76% and 100%) (3-10d)
What is the proposed mechanism of leptospirosis-induced polyuria?
Decreased vasopressin responsiveness of the inner medullary collecting ducts
True or False: Thrombocytopenia is common in dogs with leptospirosis.
True
What does leptospirosis microagglutination test (MAT) test for?
The antibodies in the blood target certain serovars
In leptospirosis microagglutination test (MAT) test, what result is considered positive?
1) titer ≥ 1600 in the absence of vaccination
2) A 4-fold change in titer (blood collected at acute infection phase and then 2-4 weeks later)
True or False: In the 1st week of illness, dogs frequently have negative MAT results.
True
If you want to perform leptospirosis PCR tests, when should you collect blood sample and urine sample, respectively?
First week: blood sample
Second week: blood + urine sample
- In the first 10 days of infection, organism numbers are highest in blood, and thus blood is the sample of choice during the first week of illness. After that time, organisms are present in highest concentration in urine.
True or False: In a recent study published by Zamagni and colleagues in The Veterinary Journal in 2020, dogs with AKI secondary to leptospirosis had significantly increased fraction excretion of K as well as more frequent positive dipstick glucosuria than dogs with AKI secondary to other causes
True.
- In the same studies, frequency and severity of granular cast as well as urinary NGAL did not differ significantly between two groups.
List 3 mechanisms of leptospirosis causing kaliuresis.
1) Inhibit Na,K-ATPase
2) Increase aldosterone and cortisol production
3) Inhibit NKCC2 on the thick ascending loop of Henle
In dogs with leptospirosis, which immunoglobulin can be detected earlier, IgM or IgG?
IgM
- Presence of igM indicates recent/current infection. It appears as early as 4–6 days after infection and remains detectable for only a few months.
- Witness test → 10 days
Which antibiotic can clear the leptospires in the blood and the organs?
Doxycycline
Dose: 5 mg/kg PO q12h x 2 weels
* Usually start with ampicillin at the beginning if animal cannot tolerate doxycycline
Cytauxzoon
Lone start tick in cats
Protozoa that causes very acute, fulminant disease with hemolysis, icterus and pancytopenia
Treatment with atovaquone and azithromycin (similar to B. gibsoni in dogs) but prognosis very guarded
Hepatozoon
protozoal disease
dogs eat the tick
- H. canis (brown dog tick) usually silent disease, but 1/3 can display thrombocytopenia
- H. americanum (gulf coast tick), symptomatic with severe chronic progressive skeletal and cardiac muscle impairment. Difficult to treat: TMPS+Clynda+ pyrimethamine followed by long term decoquinate
Describe the cellular uptake mechanism for aminoglycosides
- stage I: positively charged aminoglycoside interact with gram - outer membrane (lipopolysaccharide negatively charged)
- stage II (energy-dependent phase) after aminoglycoside entered the cell –> alteration of protein synthesis with defect of cell membrane –> non-specific channels allowing more glycosides in
- stage III (energgy-dependent) more aminoglycosides in via pore and formation of more gaps in membrane until bacterial cell death
Energy dependency = aminoglycosides not active in conditions of low O2 and low pH which inhibits oxidative phosphorylation (i.e. abscesses)
Side effects of aminoglycosides
- nephrotoxicity (5-15% incidence)
- ototoxicity
- NM blockade
ideally TDM with amikacin at <2.5ug/ml and genta <1ug/ml
Tick borne diseases summary
Angio SNAP sensitivity and specificity + discuss limitations
Sensitivity 85-97%
Specificity 94-100%
However detects adult antigen so positive only after 7-11 weeks post infection
Coagulopathic dogs often present when still in larvae phase so can easily be AngioSNAP negative
What is the gold standard for Angiostrongylus?
Baermann’s test
Only identifies larvae
L1 not constantly shed so need to collect faeces over 3 days
What’s the protocol for febendazole to treat Angiostrongylus?
25mg/kg for 20 days or 50mg/kg for 10 days
What’s the protocol to treat Angiostrongyluswith milbemycin?
Once weekly for 4 weeks
What’s the protocol to treat Angiostrongylus with imidacloprid/mocidectin?
2 treatments 4 weeks apart = 100% resolution
