Ruminant Top 15 Small Ruminant Diseases - Part 1 Flashcards
what lesions are typically seen with orf virus in small ruminants? what location?
usually in young/newly introduced animals - painful papules, vesicles, pustules, & crusts at mucocutaneous junction of lips
what other additional locations can lesions from orf virus be seen?
around erupting incisor teeth, buccal mucosa, anorexia, coronary bands causing lameness, & sometmes, perineum, eyes, & ears
what is another name for orf virus?
contagious ecthyma
other than the skin lesions, what other clinical signs may be seen with orf virus in small ruminants?
weight loss due to poor appetite & gangrenous mastitis in ewes
what is the etiology of orf virus?
parapox virus
how is orf virus diagnosed?
history, exam, & pcr/electron microscopy
what is the typical course of orf virus?
1-4 weeks
T/F: orf virus usually heals without any scars
TRUE
T/F: there is a high resistance to reinfection of orf virus after recovery
TRUE
what treatment is used for small ruminants with orf virus?
abx (topical or parenteral for secondary infections), supportive care, & larvicides/repellants to prevent larval screw worm myiasis
what is the risk posed by orf virus?
zoonotic, very contagious with direct contact by affected animals
how is vaccination used to prevent disease from orf virus? when should it not be used?
effective when given during an outbreak - don’t vaccinate on orf-free farms because vaccine can cause disease
T/F: orf virus is more severe in goats than sheep but lesson common in goats
TRUE
how is orf virus prevented?
isolate or cull affected animals & then vaccinate the rest
what is another name for bloody scours in small ruminants?
enterotoxemia type c
what is the classic case presentation of bloody scours in small ruminants?
bloody diarrhea in kids/lambs, anorexia, lethargy, gi pain, seizures, opisthotonus, ataxia, & peracute death without any premonitory signs
what are other names for enterotoxemia type d?
pulpky kidney & overeating disease
what is the classic case presentation of enterotoxemia type d?
affects largest, fastest growing lambs (less commonly in kids), anorexia, lethargy, gi pain, seizures, opisthotonus, ataxia, & peracute death without premonitory signs
what is the classic case presentation of tetanus in small ruminants?
history of wound 10-14 days prior, stiffness that often starts in masseter muscles, generalized stiffness (sawhorse stance), tachypnea, tachycardia, sweating, hyper-reflexive, normal consciousness, & respiratory paralysis that leads to death
what is the etiology of tetanus in small ruminants?
c. tetani neurotoxin
what is the etiology of enterotoxemia types c & d?
type c: beta toxin causes severe intestinal damage & type d: epsilon toxin
what is seen on necropsy in small ruminants that died from type d enterotoxemia?
rapid, post mortem renal autolysis & hemorrhagic ulcerative enteritis
how are enterotoxemias in small ruminants diagnosed?
gi content smears include large numbers of gram positive rods, toxin ID using PCR or ELISA on intestinal fluid
how is tetanus diagnosed in small ruminants?
gram positive bacteria seen in smear from wound
how are enterotoxemias in small ruminants prevented?
type c: good udder hygiene & vaccination, type d: minimize rapid feed changes & vaccinate
how is enterotoxemia type c treated?
rarely successful - hyperimmune serum & oral abx likely better for at risk herd mates
how is tetanus in small ruminants treated?
rarely done, supportive care
what are some additional causes that lead to enterotoxemia types c & d in small ruminants?
type c due to drinking too much milk/indigestion, type d due to overeating more common in sheep especially lambs under 2 weeks old or weaned on feed lots/lush pasture
what animals are most often affected by enterotoxemia type d?
sheep more common than goats - especially lambs
what is the pathophysiology of tetanus?
sporulates in anaerobic necrotic tissue & produces a neurotoxin which causes spasmodic, tonic muscle contractions
T/F: c. perfringens is normally present in small numbers in the gi tracts of small ruminants
TRUE
what is the classic case of gastrointestinal parasitism in small ruminants?
weight loss, diarrhea, anemia, bottle jaw, generalized weakness, poor coat, decreased milk production, wool break, & death
what are the most common gi parasites affecting small ruminants?
eimeria (host species specific), ostertagia, trichostrongylus, & haemonchus contortus
how is a diagnosis of coccidosis made in small ruminants?
more than 20,000 oocysts/g of feces on a FEC
how is a fecal egg count used to diagnose gi parasites in small ruminants?
not very sensitive - need to do before & after treatment
how is teladorsagia infection diagnosed in small ruminants?
increased plasma pepsinogen levels
how is a FAMACHA score used for small ruminants?
sensitive indicator of anemia from haemonchus - compare inferior palpebral conjunctiva with FAMACHA card on a scale of 1-5 (normal to very anemic)
how is treatment for gi parasits determined in small ruminants?
only treat affected animals to help slow anthelmintic resistance - using targeted selected treatment (FEC/FAMACHA to determine need) & timed based on knowlegde of season & parasite life cycle
how is coccidiosis in sheep treated?
treatment is ineffective once diagnosed in in sheep - reduceseverity with toltrazuril, diclazuril, or sulfaquinoxaline
how is coccidiosis in sheep prevented?
minimize stress, crowding, severe weathing, & prophylactic coccidiostats for 28 days after lambs are introduced to a new environment (monensin)
why is a periparturient rise in egg counts of gi parasites seen in sheep? how is this addressed?
decreased immunity
how is gi parasitism in small ruminants prevented?
rotational grazing (alternate pastures with cows & horses), don’t overgrze/overcrowd pastures, & maintain a good plane of nutrition
how are gi parasites transmitted?
fecal oral - eggs shed in feces & mature into L3 which are ingested by the host, tissue migration, & maturation in gi tract to pass eggs into feces
what small ruminant gi parasites are more common in cooler winter/rainfall? what is the pathophysiology?
t. circumcincta & trichostongylus - enteritis & decreased nutrient absorption
what small ruminant gi parasite is most common in tropical/subtropical climates? what clinical signs does it cause?
haemonchus - does not cause diarrhea alone, anemia!!!!!!
what clinical signs are seen with an internal infection caused by caseous lymphadenitis?
weight loss, poor doer, thin ewe syndrome - specific signs based on organs affected
what is the classic case presentation of caseous lymphadenitis in small ruminants?
peripheral lymph node abscesses (submandibular, parotid, prescapular, & prefemoral), once draining, odorless creamy (goats) to caseous purulent (sheep) discharge, heals with a scar, recurrence common
what is the etiology of caseous lymphadenitis?
corynebacterium pseudotuberculosis - gram positive facultative intracellular bacteria
how is caseous lymphadenitis diagnosed?
culture of abscess material, for internal lesions u/s, rads, & aspirate, serology - synergistic hemolysin inhibition titer
what is the most practical treatment for caseous lymphadenitis for commercial operations?
culling
if there is a valuable animal with caseous lymphadenitis, how is it treated?
isolate, lance/drain/lavage with iodine solution,s urgical excision, abx in extralabel manner - likely to recur even with treatment
what treatment is not okay for small ruminants with caseous lymphadenitis?
formalin injection - not okay in animals intended for food & forbidden by the FDA
what is the risk of caseous lymphadenitis? how is it transmitted?
zoonotic & highly contagious - enters through breaks in skin or mucus membranes
external caseous lymphadenitis is more common in what small ruminants? what about the internal form?
goats for external & internal for sheep
caseous lymphadenitis is susceptible to what cleaning products?
bleach & chlorhexidine
how is caseous lymphadenitis prevented?
strict biosecurity, don’t contaminate environment (collect purulent material & lavage fluid), careful use of fomites, vaccinate if endemic to reduce incidence, & fly control
what are the most common causes of pneumonia in small ruminants? what is the classical clinical presentation?
ovine progressive pneumonia, maedi-visna, progressive wasting respiratory distress, CAE, chronic enzootic pneumonia, bacterial, & lungworms - sheep greater than 4 years old, indurative mastitis, coughing, discharge, dyspnea, weight loss
what is the classic case presentation of ovine pulmonary adenocarcinoma causing pneumonia?
respiratory distress & crackles throughout lung fields with copious nasal discharge
what is the classic case presentation of caprine athritis encephalitis causing pneumonia?
mostly arthritis & neuro signs, & maybe indurative mastitis with respiratory signs
what is the morbidity/mortality rate of chronic enzootic pneumonia in small ruminants?
high morbidity low mortality
what clinical signs are seen with lungworm pneumonia in small ruminants?
coughing, tachypna, & respiratory distress
what clinical signs are seen with bacterial pneumonia in small ruminants?
thicker nasal discharge
in lambs & kids with pneumonia, what are the common causes?
usually viral - PI-3, adenovirus, respiratory synctial virus, & secondary bacterial
what are common causes of pneumonia in adult small ruminants?
retroviruses in sheep: OPP, M-V, OPA, & jaagsiekte sheep retrovirus, in goats, CAE
what bacteria are often implicated in causing bacterial pneumonia in small ruminants?
mainheimia haemolytica, pastuerella multocida, chlamydia pneumoniae, salmonella, mycobacterium, & corynebacterium pseudotuberculosis
what parasites are often implicated in causing pneumonia in small ruminants?
dictocaulus filaria in the bronchi, muellerius capillaris in alveoli & lung parenchyma which is worse in goats than sheep, & protostrongylus refescens in the bronchi
how is pneumonia caused by parainfluenza-3 in small ruminants diagnosed?
virus isolation on nasal swab or serology (2 titers, 2-4 weeks apart)
how is pneumonia caused by OPA/M-V/CAE in small ruminants diagnosed?
ultrasound of the lungs, agar gell test or ELISA, necropsy with heavy lungs that don’t collapse, PCR, or virus isolation
how is bacterial pneumonia in small ruminants diagnosed?
culture tracheal wash/lung material
how is chronic enzootic pneumonia in small ruminants diagnosed?
necropsy - challenging diagnosis
how is parasitic pneumonia in small ruminants diagnosed?
1st stage larva seen on fecal float or in bronchoalveolar lavage fluid, use baermann technique
what bacteria are normal inhabitants of the upper respiratory tract in small ruminants?
m. haemolytica & p. multocida
what part of the respiratory system is affected d. filaria & p. rufescens?
bronchi
what part of the respiratory system is affected by m. capillaris? what small ruminant is it worse in?
alveoli & lung parenchyma - worse in goats
parasitic pneumonia in small ruminants affects what part of the body & is rarely what?
margins of the diaphragmatic lung lobes - rarely clinical
how is viral pneumonia treated in small ruminants?
supportive care, abx for secondary infections
how is pneumonia caused by OPA/M-V/CAE treated in small ruminants?
none, serology done twice a year & cull positive animals
how is bacterial pneumonia in small ruminants treated?
supportive care, improve ventilation
how is chronic enzootic pneumonia in small ruminants treated?
maybe long acting oxytetracycline (off label)
how is parasitic pneumonia in small ruminants treated?
anthelmintics and vaccination
