Domestic cats seropositive for Felis catus gammaherpesvirus 1 are often qPCR negative

Abstract

Felis catus gammaherpesvirus 1 (FcaGHV1) is a newly described virus that infects domestic cats. To identify FcaGHV1 antigens, we developed an immunofluorescent antibody assay by expressing FcaGHV1 open reading frames (ORFs) in feline cells and incubating fixed cells with sera from FcaGHV1-positive cats. Of the seven ORFs tested, ORF52 and ORF38 had the strongest, most consistent antibody responses. We used recombinant ORF52 and ORF38 proteins to develop two FcaGHV1 ELISAs. These assays were used to detect reactivity in cats previously tested by qPCR for FcaGHV1 in blood cell DNA. Results indicated 32%FcaGHV1seroprevalence, compared to 15%qPCR-evaluated prevalence (n=133);all but one qPCR positive animal was seropositive. ELISA results confirmed infection risk factors previously identified by qPCR: geographic location, male sex, and adult age. These data suggest that FcaGHV1is a common infection of domestic cats that has a seropositive but often qPCR negative state characteristic of herpesviral latency.

Feline Leukemia Virus (FeLV) Disease Outcomes in a Domestic Cat Breeding Colony: Relationship to Endogenous FeLV and Other Chronic Viral Infections

“…FcaGHV-1 was identified in approximately 12% in this colony by qPCR, a prevalence similar to that in other populations (28)(29)(30)(31). Serological analysis has indicated that approximately half of cats with FcaGHV-1 exposure (as evidenced by reactive antibodies) are qPCR negative (27), suggesting that the actual incidence in this colony may be higher than 12%. Despite the close proximity of members of this colony, all but one of the FcaGHV-1-positive cats was male.…”

“…FFV and FcaGHV-1 are common chronic infections of domestic cats that to date are considered to represent apathogenic infections (27)(28)(29)(30)(31)(32)(33). FCoV is a prevalent chronic infection of domestic cats that predominantly occurs in an apathogenic enteric form but can emerge as a highly virulent pathogen, resulting in feline infectious peritonitis (FIP) in certain circumstances (34).…”

Identification of a novel gammaherpesvirus in Canada lynx (Lynx canadensis)

“…In this study, we designed and utilized LcaGHV1-specific nested PCR to determine prevalence in each lynx population, however this method is known to potentially underestimate the true prevalence. It is known that seropositive cats may give a negative PCR result (Stutzman-Rodriguez et al, 2016). The fact that herpesviruses establish latent infections means that there can be vanishingly small amounts of viral DNA present in the host (Barton et al, 2011;Speck and Ganem, 2010).…”

“…This analysis did not indicate any significant relationships (Table 3). Male sex has consistently been a strong risk factor for FcaGHV1 in domestic cats Ertl et al, 2015;Kurissio et al, 2018;McLuckie et al, 2016;Stutzman-Rodriguez et al, 2016;Troyer et al, 2014) but not for LruGHV1 in bobcats (Loisel et al, 2018;Troyer et al, 2014). The lack of a sex association in lynx suggests that the strong association between males and felid GHV infection may be specific to domestic and not wild cat species .…”

Novel gammaherpesvirus infection in felids: a brief review

“…FcaGHV1 DNA positive cats on PCR were 2.82 (95% CI 1.24% to 6.58%) times more likely to be classed as sick when compared to PCR negative cats [8], although no further details of diseases associated with virus positivity were given. Having said that seropositive cats were noted in one study often to be PCR negative [11] as might be expected in a state of classic herpesvirus latency. On the other hand the high coprevalence of haemoplasma infection in FcsGHV1 infected cats [12] suggests that co-transmission may occur.…”