164 - Madariaga virus: What are you and where are you found?

Prior to 2010, eastern equine encephalitis virus (EEEV) was known from North, Central, and South America, with lineage 1 found in North America and lineages 2-4 found in Central/South America. The Central/South American lineages 2-4 were considered to be much less virulent due to the scarcity of reported disease in either horses or humans. In 2010, it was shown that lineages 2-4 of EEEV were a distinct virus, Madariaga virus (MADV), in the EEEV complex. Recent finding of severe disease in both humans and equines indicates that MADV can be highly virulent. Unfortunately, very little is known about the epidemiology of MADV to include the identity of the vertebrate amplifying hosts and the actual vectors, or even its actual distribution. We will present current knowledge on amplifying vertebrate hosts, more likely to be small rodents for MADV in contrast to avian species for EEEV, and potential enzootic vectors are probably Culex(Melanoconion) spp. for MADV in contrast to Culiseta melanura for EEEV. Data will also be presented on the current known distribution of MADV. As MADV is now known to be causing human and equine deaths, it is critical to develop a better understanding of the factors affecting MADV transmission.