Feline Leukemia Virus p27 Antigen Concentration and Proviral DNA Load Are Associated with Survival in Naturally Infected Cats.

Longitudinal studies of cats naturally infected with feline leukemia virus (FeLV) are important for understanding disease outcomes. Levels of p27 antigen and copy numbers of proviral DNA have been associated with FeLV-infection courses. The purpose of this prospective study was to establish cutoff values for p27 antigen concentration and proviral DNA load that distinguished high positive from low positive groups of cats and to evaluate an association with survival. At enrollment, 254 cats were tested by point-of-care and microtiter plate enzyme-linked immunosorbent assays (ELISAs) for p27 antigen and real-time polymerase chain reaction (PCR) for proviral DNA. The 127 positive cats were retested monthly for six months and monitored for survival over the four-year study. A receiver operating characteristic-based analysis of samples with concordant or discordant qualitative results for p27 antigen and proviral DNA was used to establish cutoff values, and when applied to test results at enrollment for classifying cats as high positive or low positive, a significant difference in survival was observed. High positive cats had a median survival of 1.37 years (95% CI 0.83-2.02) from time of enrollment, while most low positive cats were still alive (93.1% survival). Quantitative results for p27 antigen concentration and proviral DNA load were highly correlated with survival times in FeLV-infected cats.

RETROSPECTIVE ANALYSIS AND VALIDATION OF SERUM SYMMETRIC DIMETHYLARGININE (SDMA) CONCENTRATIONS IN CHEETAHS ( ACINONYX JUBATUS).

Kidney disease is common among captive cheetahs ( Acinonyx jubatus). Serum creatinine is the most common measurement to estimate glomerular filtration rate (GFR) because of the ease of its clinical use, but it is a crude estimate that only increases after significant disease is already present and is affected by extrarenal factors. Symmetric dimethylarginine (SDMA) is a renal biomarker in humans, dogs, and cats that correlates with serum creatinine and GFR and appears to be an earlier and more specific biomarker for kidney disease. Ninety-two banked serum samples from 11 cheetahs housed at the Oklahoma City Zoo from 1992 to 2012 were retrospectively analyzed. Histopathology results were available for 10/11 cheetahs, and all 10 had histologic renal lesions. General categories of renal lesions included glomerulosclerosis (7/10; 70%), amyloidosis (7/10; 70%), inflammatory (9/10; 90%), and oxalate nephrosis (2/10; 20%). SDMA immunoassay and mass spectrometry were measured for validation and compared with creatinine to assess for correlation. Serum creatinine concentrations were determined by enzymatic colorimetric methods. SDMA immunoassay was validated in cheetahs and correlated well with serum creatinine ( R2=0.687; P < 0.0001). SDMA and serum creatinine measured from freeze-thawed stored samples show high correlation in individual cheetahs ( R2 = 0.972; P < 0.0001). These data support that SDMA could be a promising renal biomarker in cheetahs. Further research is warranted to investigate whether SDMA might be an earlier indicator of kidney disease in cheetahs and whether this assay can be extended to other nondomestic carnivores.

Comparison of Antemortem and Environmental Samples for Zebrafish Health Monitoring and Quarantine.

Molecular diagnostic assays offer both exquisite sensitivity and the ability to test a wide variety of sample types. Various types of environmental sample, such as detritus and concentrated water, might provide a useful adjunct to sentinels in routine zebrafish health monitoring. Similarly, antemortem sampling would be advantageous for expediting zebrafish quarantine, without euthanasia of valuable fish. We evaluated the detection of Mycobacterium chelonae, M. fortuitum, M. peregrinum, Pseudocapillaria tomentosa, and Pseudoloma neurophilia in zebrafish, detritus, pooled feces, and filter membranes after filtration of 1000-, 500-, and 150-mL water samples by real-time PCR analysis. Sensitivity varied according to sample type and pathogen, and environmental sampling was significantly more sensitive than zebrafish sampling for detecting Mycobacterium spp. but not for Pseudocapillaria neurophilia or Pseudoloma tomentosa. The results of these experiments provide strong evidence of the utility of multiple sample types for detecting pathogens according to each pathogen's life cycle and ecological niche within zebrafish systems. In a separate experiment, zebrafish subclinically infected with M. chelonae, M. marinum, Pleistophora hyphessobryconis, Pseudocapillaria tomentosa, or Pseudoloma neurophilia were pair-spawned and individually tested with subsets of embryos from each clutch that received no rinse, a fluidizing rinse, or were surface-disinfected with sodium hypochlorite. Frequently, one or both parents were subclinically infected with pathogen(s) that were not detected in any embryo subset. Therefore, negative results from embryo samples may not reflect the health status of the parent zebrafish.