Prevalence of antibodies to Japanese encephalitis and West Nile viruses among wild birds in the Krishna-Godavari Delta, Andhra Pradesh, India

Abstract

In the Krishna-Godavari Delta region of the State of Andhra Pradesh, India, 866 sera obtained from trapped birds of 13 species were tested for neutralizing antibody to Japanese encephalitis (JE) virus; two species of birds belonging to the family Ardeidae, Ardeola grayii (pond heron) and Bubulcus ibis (cattle egret), contributed 514 of these sera. Neutralizing antibody to JE virus--i.e. sera giving positive reactions--was detected in 179 sera (34.8%) from these two species; in addition, two sera (0.4%) gave equivocal reactions, presumably indicating partial protection. There were only nine positive reactors (2.6%) among the remaining 352 sera from all other bird species. Of the 181 sera from ardeid birds in which neutralizing activity was detected, 174 were tested for neutralizing antibody to West Nile (WN) virus. The results indicated that 35.6% of these 179 sera had antibody specific to JE virus only and 63.8% possessed neutralizing antibodies to JE virus or to WN virus or to both; these figures represent 12.5% and 22.5% , respectively, of the total of 514 birds of these two species which were tested for neutralizing antibody to JE virus. The findings suggest that ardeid birds may be involved in the natural cycle of JE virus and, possibly, also of WN virus in India.

Prevalence of West Nile Virus Neutralizing Antibodies in Wild Birds from the Camargue Area, Southern France

“…Conversely, only three of the 201 Cattle Egret nestlings sampled from site two had WNV neutralizing antibodies; titers ranged from 40 to 320 (Table 1). The corresponding antibody prevalence was 1.6% (95% confidence limit, 0.3-4.6%), which is much lower than that observed in previous studies from Russia, India, and Israel (Berezin, 1971;Rodrigues et al, 1981;Jamgaonkar et al, 2003;Mumcuoglu et al, 2005). Because all nestlings were less than 25 days old, antibodies were likely of maternal origin (Rodrigues et al, 1981;Reisen et al, 2005) and thus indicate exposure of adult females to flaviviruses either in the Camargue or elsewhere in the Mediterranean Basin.…”

“…These species included many small passerine birds, because species of the order Passer-iformes are believed to be among the most competent for WNV transmission (Work et al, 1955;Komar et al, 2003). We also sampled Cattle Egrets (Bubulcus ibis) because they are often in close contact with horses, breed in colonies where Culex mosquito vectors are abundant (Mouchet et al, 1970), and have been postulated as amplifying hosts for WNV (Rodrigues et al, 1981;Hubalek, 2004). A recent study reported that experimentally infected Cattle Egret chicks do not develop a high level of viremia (Reisen et al 2005) but, in the Camargue wetlands, even a low viremia level in birds may contribute to virus amplification.…”

North American Birds as Potential Amplifying Hosts of Japanese Encephalitis Virus

“…Several avian species have exhibited JEV viremia upon experimental and natural infections [5][6][7][8][9] and naturally acquired anti-JEV antibodies have been detected in a variety of free-ranging birds in India, Japan, Korea, and West Bengal. 5,[10][11][12][13][14][15][16] However, comparisons of infection outcomes for different JEV strains among a diversity of avian species are needed to better define the potential role of birds in the epidemiology of the virus. Furthermore, pre-emptive knowledge of the responses of North American birds to JEV infection would help guide surveillance efforts and management strategies if this virus is introduced to the western hemisphere.…”

West Nile Virus Infection among Animals and Humans in India

“…Of these 3.37% were tested positive for WNV antibodies by HI and 3.19% were found positive by VNT, which indicates circulation of WNV among Equine population (Table 1). In southern India, JEV/WNV neutralizing antibodies have been detected in ardeid birds mainly from the pond herons (Ardeola grayii) and cattle egrets (Bubulcus ibis), indicating their role in the natural cycle of WNV in India (Rodrigues et al, 1981). WNV strain P-4230 has been isolated from a laboratory worker who got infected while handling the Indian mosquito strain G-2266 and the Egyptian human strain E-101 (Paramasivan et al, 2003).…”

“…Animals and humans act as dead-end host (Paramasivan et al, 2003). In India, WNV infection has been reported from human (Balakrishnan et al, 2013;Chowdhury et al, 2014), animals (Ratho, et al, 1999) and birds (Mishra et al, 2012;Rodrigues et al, 1981). The purpose of this review is to review the status of WNV infection in India, both in human and animal population.…”