Ecologic studies of Venezuelan encephalitis virus and isolations of Nepuyo and Patois viruses during 1968-1973 at a marsh habitat near the epicenter of the 1969 outbreak in Guatemala

Area of Science:

• Arbovirology
• Ecology
• Epidemiology

Background:

• Venezuelan encephalitis (VE) virus outbreaks pose significant public health risks.
• Understanding the ecological dynamics of VE virus is crucial for predicting and preventing future epidemics.

Purpose of the Study:

• To investigate the ecologic status of Venezuelan encephalitis (VE) virus in a marsh habitat near the 1969 outbreak epicenter in Guatemala.
• To determine the yearly presence and transmission patterns of VE virus in this enzootic setting.

Main Methods:

• Yearly isolation of VE virus from sentinel hamsters and mosquitoes (Culex, Mansonia, Aedes) during 1968-1973.
• Detection of viral activity across different zones within the marsh and surrounding areas.
• Serological testing (hemagglutination-inhibition and neutralization) of wild mammals, humans, dogs, birds, sentinel rabbits, and chickens for antibodies.

Main Results:

• VE virus was isolated annually from sentinel hamsters and mosquitoes, confirming its enzootic nature.
• Virus was detected throughout the marsh and up to 18 km from the central study site.
• Antibodies were prevalent in wild terrestrial mammals, humans, and dogs, but not wild birds.
• Asymptomatic seroconversion occurred in human residents, while sentinel rabbits and chickens showed limited antibody development.

Conclusions:

• The marsh habitat serves as an enzootic focus for Venezuelan encephalitis (VE) virus.
• The study highlights the role of various hosts and vectors in maintaining the virus's circulation.
• Findings underscore the importance of continued surveillance in areas with potential VE virus activity.