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- Author or Editor: Scott P. Collins x
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Abstract
Objective—To evaluate the influences of animal age, bacterial coinfection, and porcine reproductive and respiratory syndrome virus (PRRSV) isolate pathogenicity on virus concentration in pigs.
Animals—Twenty-one 2-month-old pigs and eighteen 6-month-old pigs.
Procedure—Pigs were grouped according to age and infected with mildly virulent or virulent isolates of PRRSV. The role of concurrent bacterial infection was assessed by infecting selected pigs with Mycoplasma hyopneumoniae 21 days prior to inoculation with PRRSV. On alternating days, blood and swab specimens of nasal secretions and oropharyngeal secretions were collected. On day 21 after inoculation with PRRSV, selected tissues were harvested. Concentrations of PRRSV were determined by use of quantitative real-time PCR and expressed in units of TCID50 per milliliter (sera and swab specimens) or TCID50 per gram (tissue specimens).
Results—Concentrations of virus were higher in blood and tonsils of pigs infected with virulent PRRSV. Pigs infected with virulent PRRSV and M hyopneumoniae had significantly higher concentrations of viral RNA in lymphoid and tonsillar tissue. Coinfection with M hyopneumoniae resulted in a higher viral load in oropharyngeal swab specimens and blood samples, independent of virulence of the PRRSV isolate. Two-month-old pigs had significantly higher viral loads in lymph nodes, lungs, and tracheal swab specimens than did 6-month-old pigs, independent of virulence of the PRRSV isolate.
Conclusions and Clinical Relevance—Multiple factors affect PRRSV concentration in pigs, including pathogenicity of the PRRSV isolate, age, and concurrent infection with M hyopneumoniae.
Abstract
Objective—To determine risk factors for lens luxation and cataracts in captive pinnipeds in the United States and the Bahamas.
Design—Cross-sectional study.
Animals—111 pinnipeds (99 California sea lions [Zalophus californianus], 10 harbor seals [Phoca vitulina], and 2 walruses [Odobenus rosmarus]) from 9 facilities.
Procedures—Eyes of each pinniped were examined by a veterinary ophthalmologist for the presence of cataracts or lens luxations and photographed. Information detailing husbandry practices, history, and facilities was collected with a questionnaire, and descriptive statistical analyses were performed for continuous and categorical variables. Odds ratios and associated 95% confidence intervals were estimated from the final model.
Results—Risk factors for lens luxation, cataracts, or both included age ≥ 15 years, history of fighting, history of ocular disease, and insufficient access to shade.
Conclusions and Clinical Relevance—Diseases of the lens commonly affect captive pinnipeds. Access to UV-protective shade, early identification and medical management of ocular diseases, and prevention of fighting can limit the frequency or severity of lens-related disease in this population. An extended life span may result from captivity, but this also allows development of pathological changes associated with aging, including cataracts.
