Surveillance Potential of Non-Native Hawaiian Birds for Detection of West Nile Virus

Abstract

Abstract. West Nile virus (WNV) was first detected in North America in 1999. Alaska and Hawaii (HI) remain the only U.S. states in which transmission of WNV has not been detected. Dead bird surveillance has played an important role in the detection of the virus geographically, as well as temporally. In North America, corvids have played a major role in WNV surveillance; however, the only corvid in HI is the endangered Hawaiian crow that exists only in captivity, thus precluding the use of this species for WNV surveillance in HI. To evaluate the suitability of alternate avian species for WNV surveillance, we experimentally challenged seven abundant non-native bird species present in HI with WNV and compared mortality, viremia, oral shedding of virus, and seroconversion. For detection of WNV in oral swabs, we compared viral culture, reverse-transcriptase polymerase chain reaction, and the RAMP ® test. For detection of antibodies to WNV, we compared an indirect and a competitive enzyme-linked immunoassay. We found four species (house sparrow, house finch, Japanese white-eye, and Java sparrow) that may be useful in dead bird surveillance for WNV; while common myna, zebra dove, and spotted dove survived infection and may be useful in serosurveillance.

Current Progress of Avian Vaccines Against West Nile Virus

“…No clinical signs are observed in most WNV-infected birds, and, when they show up, the most common are lethargy, reluctance to move, ruffled feathers, and lack of appetite with marked body weight losses ( Figure 4) [7,8,63,75]. Dehydration [70], intermittent head twitching [70], convulsions [47,76], profuse oral and nasal discharge [77], or reduced fecal output [78] are less common. When a fatal outcome occurs, it happens within the first 24 h after the onset of clinical signs [7,8].…”