Neutralising antibodies for Mayaro virus in Pantanal, Brazil

Abstract

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 sero- positive 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.

Prostaglandin A1 triggers Mayaro virus inhibition and heat shock protein 70 expression in an epithelial cell model

“…MAYV detection in equids, sheep and caimans provided indirect evidence of MAYV circulation in the Brazilian Western region 4 , reinforcing the outbreak potential of this virus, and revealing previously unknown hosts. MAYV infection rates may be underestimated, as MF is commonly mistaken for dengue, in the absence of specific diagnostics 12 .…”

“…Joint pain, characteristic of chronic MF, may persist for at least a year after infection. In MAYV endemic areas, patients with joint pain who are seronegative for arthritis may be infected with MAYV 4,5 .…”

Transmission potential of Mayaro virus by Aedes albopictus, and Anopheles quadrimaculatus from United States

“…New World primates of the families Cebidae and Callithricidae are considered as potential natural reservoirs for the virus [6,7]. Furthermore, the virus has been found in a migrating bird, equids, anteaters, armadillos, opossums, and rodents [8,9].…”

Mayaro virus in Latin America and the Caribbean

“…Further evidence of the virus's potential to emerge in new areas was provided when sheep, caiman, and equids were sampled from 16 cattle ranches across the Pantanal region of Brazil from October 2009 through January 2011 (7). Results from the study showed that 10 of the 748 equids were seropositive for MAYV, demonstrating the first evidence of MAYV circulation in the southern Pantanal.…”

“…Since equids tested negative for MAYV in previous investigations, the authors of the study suggested that MAYV circulation in the Pantanal might be a recent occurrence. More research is needed to identify amplifier hosts and vectors, and to understand the ecology of the transmission of the virus (7).…”