Arbovirus Infection

The term “arbovirus viruses” describes viruses transmitted to vertebrates by arthropod vectors, including mosquitos, ticks, and flies. Several arboviruses have been described; however, this chapter will discuss arboviruses infecting domestic and wild birds. These viruses belong to three families, namely, Togaviridae (Highlands J Virus, Eastern equine encephalitis, Western equine encephalitis), Flaviviridae (Turkey meningoencephalitis, Tembusu virus, West Nile virus, and Usutu virus), and Bunyaviridae (Turlock-like Bunyavirus). Highlands J (HJ), Eastern equine encephalitis (EEE), Western equine encephalitis (WEE), Israel turkey meningoencephalitis (ITM), and Western (WN) Nile viruses infect turkeys. Eastern equine encephalitis and Western equine are zoonotic and cause flu-like illness with sudden onset fever, headache, and fatigue. Some patients may develop neuroinvasive disease, with typical signs of meningitis, encephalitis, paralysis, convulsions, and coma in humans. The horse is the primary host of these two viruses. Arboviruses can be isolated in newly born mice. However, newborn chicks are highly susceptible, but it is not recommended for arbovirus isolation to avoid potential aerosol transmission. Virus identification can be done using PCR and IFA. Additionally, a hemagglutination inhibition test can be used for the diagnosis of ITM (ITM agglutinates goose red blood cells). Differential diagnosis of arboviruses from closely related agents, such as diseases causing nervous manifestations (i.e., Newcastle disease, avian encephalomyelitis, and Clostridium botulinum) and diseases causing a drop in egg production (i.e., avian influenza and turkey rhinotracheitis) should be considered.