A newly recognized vesiculovirus, Calchaqui virus, and subtypes of Melao and Maguari viruses from Argentina, with serologic evidence for infections of humans and horses.

The research article reveals the identification of a new virus named Calchaqui and subtypes of Melao and Maguari viruses from mosquitoes in Argentina, with evidence of infections in humans and horses.

Strains Isolated

• In 1983, during an outbreak of western equine encephalitis in Argentina’s Santa Fe Province, 17 virus strains were isolated from collected mosquitoes.
• The strains of western equine encephalitis, Venezuelan equine encephalitis, St. Louis encephalitis, and Antequera viruses were recognized among the isolates.
• The researchers also identified several bunyaviruses of the California and Bunyamwera serogroups and a newly discovered vesiculovirus.

Identification of New Subtypes and Virus

• The scientists used complement fixation and neutralization tests to identify these viruses.
• The California serogroup virus was confirmed as a subtype of Melao virus, whereas the Bunyamwera serogroup virus belonged to both Maguari and Playas viruses subtypes.
• The newly discovered vesiculovirus was identified as a different pathogen, and the researchers proposed the name Calchaqui for it.

Serosurvey of Horses and Humans

• The researchers conducted a limited serosurvey in the Santa Fe Province and horses from the neighboring Santiago del Estero Province.
• The purpose was to understand the prevalence of neutralizing antibodies to the subtypes of Melao and Maguari viruses and to Calchaqui virus.
• The results showed a high prevalence of antibodies to these three agents, indicating these viruses’ disease potential in horses.
• The identified viruses and subtypes are closely related to several other viruses known to cause diseases in horses, which necessitates further studies into their pathogenic potential.