Diagnostic Uncertainty and the Epidemiology of Feline Foamy Virus in Pumas (Puma concolor)

Abstract

Feline foamy virus (FFV) is a contact-dependent retrovirus forming chronic, largely apathogenic, infections in domestic and wild felid populations worldwide. Given there is no current ‘gold standard’ diagnostic test for FFV, efforts to elucidate the ecology and epidemiology of the virus may be complicated by unknown sensitivity and specificity of diagnostic tests. Using Bayesian Latent Class Analysis, we estimated the sensitivity and specificity of the only two FFV diagnostic tests available—ELISA and qPCR—as well as the prevalence of FFV in a large cohort of pumas from Colorado. We evaluated the diagnostic agreement of ELISA and qPCR, and whether differences in their diagnostic accuracy impacted risk factor analyses for FFV infection. Our results suggest ELISA and qPCR did not have strong diagnostic agreement, despite FFV causing a persistent infection. While both tests had similar sensitivity, ELISA had higher specificity. ELISA, but not qPCR, identified age to be a significant risk factor, whereas neither qPCR nor ELISA identified sex to be a risk factor. This suggests FFV transmission in pumas may primarily be via non-antagonistic, social interactions between adult conspecifics. Our study highlights that combined use of qPCR and ELISA for FFV may enhance estimates of the true prevalence of FFV and epidemiological inferences.

Species, sex and geographic variation in chlamydial prevalence in abundant wild Australian parrots

“…This lack of relationship (and our recapture findings) indicate that neither PCR nor serology alone can confirm the presence or absence of chlamydial infection in a population. Similar results were found for feline foamy virus infection in wild pumas (Puma concolor) where ELISA and qPCR did not have strong diagnostic agreement 33 . We suggest that using both PCR and serology is desirable for accurate estimation of chlamydial prevalence, and epidemiological inference.…”

Viral Sequences Recovered From Puma Tooth DNA Reconstruct Statewide Viral Phylogenies

“…We detected FFV in seven percent of the tooth samples, in comparison previous evaluation of other pumas from Colorado detected FFV in 61% (qPCR, detection of viral genome) or 77% (ELISA, detection of antibodies) (Kechejian et al, 2019;Dannemiller et al, 2020). We detected FIVpco in 23% of the tooth samples, which was closer to the 48% detected via qPCR from other Colorado puma blood samples (Fountain-Jones et al, 2021).…”

Chlamydial diversity and predictors of infection in a wild Australian parrot, the Crimson Rosella ( Platycercus elegans )

“…It is important to note that only one individual in our study tested positive using both methods, with 21% individuals testing positive using only one assay. Our findings suggest that neither PCR nor serological methods have 100% sensitivity or specificity, and that reliance on a single imperfect diagnostic test is likely to result in missing information about current and past infection in wildlife (Dannemiller et al, 2020). For Chlamydia, the use of multiple tests may be particularly important, given the intermittency of cloacal shedding (Harkinezhad et al, 2009) and lower specificity of serological techniques (Bommana et al, 2019).…”