West Nile Virus Serosurveillance in Iowa White-Tailed Deer (1999–2003)

Abstract

Sera from white-tailed deer (Odocoileus virginianus) were collected in Iowa during the winter months (1999-2003), 2 years before and after West Nile virus (WNV) was first reported in Iowa (2001), and were analyzed for antibodies to WNV. Samples from 1999 to 2001 were antibody negative by blocking enzyme-linked immunosorbent assay (bELISA) and plaque reduction neutralization test (PRNT(90)). Prevalence derived from bELISA (2002, 12.7%; 2003, 11.2%) and WNV PRNT(90) (2002, 7.9%; 2003, 8.5%) assays were similar. All samples were negative for antibodies against St. Louis encephalitis virus as determined by PRNT(90). Antibodies to flaviviruses were detected by indirect enzyme-linked immunosorbent assay (iELISA) prior to the first WNV cases reported in Iowa (1999-2001) with prevalence ranging from 2.2% to 3.2%, suggesting the circulation of an additional undescribed flavivirus prior to the introduction of WNV into the area. Flavivirus prevalence as determined by iELISA increased in 2002 and 2003 (23.3% and 31.9%, respectively). The increase in prevalence exceeded estimates of WNV prevalence, suggesting that conditions favored general flavivirus transmission (including WNV) during the 2002-2003 epizootic. These data indicate that serologic analysis of deer sera collected from hunter harvests may prove useful for surveillance and evidence of local transmission of WNV and other pathogens and identify white-tailed deer as a species for further studies for host competency.

Spatio-temporal trends and risk factors affecting West Nile virus and related flavivirus exposure in Spanish wild ruminants

“…Similar seroprevalences were also found in white-tailed deer in the United States [22, 23]. In contrast, a limited number of wild ruminants from south-western Spain tested during surveillance of WNV outbreaks were negative for flavivirus antibodies using the same bELISA [8].…”

“…Antibodies against St. Louis encephalitis virus (SLEV) and WNV have been found in white-tailed deer ( Odocoileus virginianus ) from the United States [22, 23], and against TBEV and WNV in different game species from the Czech Republic [24]. In addition, fatal cases of WN fever were reported in white-tailed deer and reindeer ( Rangifer tarandus ) in North America [25, 26].…”

“…While the analysis of samples from yearlings is useful for continuous surveillance and early warning systems, the (retrospective) analysis of serum samples of individuals of all age classes is a useful tool to explore temporal and spatial trends of flavivirus activity in a given region [23]. …”

Do Wild Ungulates Allow Improved Monitoring of Flavivirus Circulation in Spain?

“…Based on the literature, we expected similar seropositivity rates in deer and wild boar (Santaella et al 2005;Halouzka et al 2008). However, free-living juvenile wild boar appeared to be far more suitable as sentinels than free-living juvenile red deer.…”

“…Studies in white-tailed deer (Odocoileus virginianus) demonstrated that it is unlikely that they are an important amplifying host for WNV (Farajollahi et al 2004), but that clinical disease and mortality are possible (one fatal case was described by Miller and associates [2005]). Several authors demonstrated seroconversion with enzyme-linked immunosorbent assays (ELISA), and by plaque-reduction neutralization tests (PNRT), and prevalences obtained ranged 0.9-12.7% (Farajollahi et al 2004;Santaella et al 2005). Regarding the Eurasian wild boar (Sus scrofa), we assume an analogous response to that of domestic pigs (Sus scrofa).…”