Ecologic Determinants of West Nile Virus Seroprevalence among Equids, Brazil

Abstract

W est Nile virus (WNV) is a widely distributed arthropodborne fl avivirus transmitted predominantly by Culex mosquitoes (1). Among infected persons, ≈20% show clinical signs, such as mild fever, rash, joint pain, headache, vomiting, and diarrhea (1,2); ≈0.7% have severe illness, such as encephalitis, meningitis, acute fl accid paralysis, respiratory failure, and even death (1). Beyond vectorborne transmission, transfusion-transmitted WNV infections have endangered blood safety (3). Equids are susceptible to WNV and develop severe disease (fatality rate <30%), are exposed to WNV vectors outside and in stables, and are spatially distributed near human settlements. Thus, equids can be sentinels for early detection of regional WNV activity (4).In the Americas, WNV gained attention after its rapid spread in the United States beginning in 1999 (4). In South America, WNV dispersion is poorly understood. Seropositive horses were found in Colom-

Seroprevalence and Risk Factors for Equine West Nile Virus Infections in Eastern Germany, 2020

“…Due to the specific ecological interactions between bird and vector populations, bird protection areas have been highlighted as a potential risk factor for infection [75][76][77][78]. As the entire study area here was located in the same temperate climatic zone, the observed differences likely cannot be explained by the prevailing climatic conditions, of which temperature and precipitation have been identified as the most critical factors influencing the spread of WNV [77,79,80]. However, variations in temperature-dependent extrinsic incubation times (EIP) have been estimated within the study area [54,80].…”

Evidence against Zika virus infection of pets and peri-domestic animals in Latin America and Africa

“…For instance, experimental infection and serological evidence indicate circulation of West Nile virus (WNV) and Japanese Encephalitis virus (JEV) in cats and dogs [12–15] and of Wesselsbron virus (WSLV) in cattle, goat and sheep [15–21]. Virus detection by molecular methods, virus isolation and serological evidence substantiate that horses can be infected with WNV, Saint Louis Encephalitis virus (SLEV), JEV and Usutu virus (USV) [22, 23]. Livestock species, such as sheep and goats, were susceptible to ZIKV in vivo [24, 25], and although ZIKV-specific neutralizing antibodies were reported in sero-epidemiological studies in cattle and sheep from Brazil and in horses from French Pacific Islands [26, 27], only few flaviviruses beyond ZIKV were used in those studies to rule out potentially unspecific test results elicited by cross-reactive flavivirus antibodies.…”

Serological differentiation of West Nile virus‐ and Usutu virus‐induced antibodies by envelope proteins with modified cross‐reactive epitopes

“…However, the sample size of USUV positive sera in general and USUV IgM positive sera in particular used in this study was limited due to the low number of diagnosed human cases and a further validation of the assay would be necessary with a higher sample quantity. Given the importance of epidemiological surveillance of WNV and USUV in susceptible vertebrates, further studies should investigate the potential of the Equad protein‐based ELISAs also with veterinary samples such as sera derived from birds like it has previously been shown for horses and mules (Oliveira‐Filho et al., 2021; Rockstroh et al., 2019).…”