Parvoviruses Flashcards
What are the characteristics of parvoviruses?
ss DNA, nonenveloped. The capsid is antigenic and is the target of neutralizing antibodies and mutation rate for this is higher than other DNA viruses
What are the variants of canine?
2a; 2b-most associated with illness; 2c-emerging and starting to become more prevalent
What is the transmission for canine?
Direct: oronasal contact with infected feces; indirect: oronasal with contaminated fomites
Where does canine replicate?
cells with high mitotic rates because the virus neds cellular nucleoprotein to replicate, so in tissues undergoing development or enteric epithelial crypt cells, hematopoeitic, lymphoid tissues
What are the phases of canine infection?
Phase 1: initial replication in lymphoid tissue of oropharynx, like tonsils, then continues to replicate in Peyer’s patches and GI lymphoid tissues. Phase 2: systemic illness from hematogenous dissemination; replicates in small intestine
What is the difference between villi and crypts?
Villi-projects into lumen and helps with digestive and absorptive functions, are mature enterocytes, non proliferative. Crypts: invaginations for secretory functions, stem cell progenitors of villus enterocytes and continuously dividing. PARVO TARGETS THE CRYPT CELLS VIA LYMPHATICS AND VASCULATURE
What’s the canine pathogenesis?
Results in epithelial cell necrosis and villous atrophy, impaired absorptive capacity, disrupted gut barrier function. Results in lymphopenia and neutropenia. If mom is infected or puppies less than 8 weeks, results in MYOCARDITIS AND MYOCARDIAL NECROSIS.
How does shedding of canine occur?
after 5 days of infection, can occur before clinical onset
What are the disease syndromes of canine?
Myocarditis: less common due to the fact that they are vaccinated or exposured before then; can see acute cardiopulmonary failure or delayed cardiac failure. Acute enteritis: most common, young puppies 6 weeks to 6 months, clinical disease worsened by parasites, stress, nutrition, can lead to intussussception.
What is the canine enteritis clinical presentation?
Develop between 5-7 days after infection, may last between 2 and 14 days, initial signs are nonspecific but they progress to hemorrhagic small bowel diarrhea and dehydration. Can see thickened and discoloured intestinal wall, watery contents, thymic atrophy. Can see blunted villi and lymphoid depletion.
How do you diagnose canine parvo?
If young, unvaccinated, and/or incompletely vaccinated dog has consistent clinical signs and history includes recently acquired/boarded/adoption from shelter. CBC shows moderate to severe leukopenia with 16% mortality. Prerenal azotemia and hypoeverything has a mortality of 36%. SNAP test detects surface protein antigen. Do PCR which detects viral nucleic acid
What are the chances of false results in canine and how do they occur?
false negative if early in the disease, mutated, diluted due to diarrhea, late in clinical disease. False positives due to vaccination with MLV
How do you treat canine parvo?
HAVE TO: restore fluids/electrolytes/metabolic abnormalities; also prevent secondary bacterial infections. Fluid therapy is ESSENTIAL and can be SQ if mild deficit or IV for more severe dehydration. If see large GI protein loss, do colloids too. Antibiotics due to risk of bacterial translocation since the crypts are affected. Antiemetics if long periods of vomiting, antidiarrheals NOT RECOMMENDED.
What happens if you do not treat canine?
Death within 1-3 days after clinical signs seen, with supportive treatment 68-92% survive, puppies that survive the first few days will recover.
How do you prevent canine?
Highly contagious so limit contamination by separating animals, use PPE, bleach. Core vaccine: MLV year after initial and then every 3 years, or inactivated in pregnant dogs or puppies before 8 weeks.
