Neutralising antibodies for Mayaro virus in Pantanal, Brazil|
Pauvolid-Corrêa, Alex; Juliano, Raquel Soares; Campos, Zilca; Velez, Jason; Nogueira, Rita Maria Ribeiro & Komar, Nicholas
The Pantanal hosts diverse wildlife species and therefore is a hotspot for arbovirus studies in South America. A
serosurvey for Mayaro virus (MAYV), eastern (EEEV), western (WEEV) and Venezuelan (VEEV) equine encephalitis
viruses was conducted with 237 sheep, 87 free-ranging caimans and 748 equids, including 37 collected from a ranch
where a neurologic disorder outbreak had been recently reported. Sera were tested for specific viral antibodies using
plaque-reduction neutralisation test. From a total of 748 equids, of which 264 were immunised with vaccine composed
of EEEV and WEEV and 484 had no history of immunisation, 10 (1.3%) were seropositive for MAYV and two (0.3%) for
VEEV using criteria of a ≥ 4-fold antibody titre difference. Among the 484 equids without history of immunisation, 48
(9.9%) were seropositive for EEEV and four (0.8%) for WEEV using the same criteria. Among the sheep, five were seropositive
for equine encephalitis alphaviruses, with one (0.4%) for EEEV, one (0.4%) for WEEV and three (1.3%) for VEEV.
Regarding free-ranging caimans, one (1.1%) and three (3.4%), respectively, had low titres for neutralising antibodies to
VEEV and undetermined alphaviruses. The neurological disorder outbreak could not be linked to the alphaviruses tested.
Our findings represent strong evidence that MAYV and all equine encephalitis alphaviruses circulated in the Pantanal.
Mayaro virus; Venezuelan equine encephalitis virus; equids; caimans; sheep; Pantanal