An outbreak of Mayaro virus disease in Belterra, Brazil. I. Clinical and virological findings

Abstract

An outbreak of human illness caused by Mayaro (MA Y) vírus occurred in Belterra, Pará, Brazil in the first half of 1978. A total of 55 cases were confirmed., 43 by vírus isolation and serology, and 12 by serology alone. The disease in Belterra presented as a distinct clinical syndrome characterized by fever, arthralgia and exanthema. No fatalities could be attributed to MA Y vírus infection. Arthralgia, accompanied by joint edema in 20% of cases, was a very prominent sigo which caused temporary incapacity in many patients. Arthralgia was present in virtually ali confirmed cases and persisted in some for at least 2 months, although with decreasing severity. Rash was present in two-thirds of the cases, and was either maculopapular or micropapular. The incidence of rash was higher in children than in adults. Contrary to arthralgia, which started with the onset of clinical illness, rash usually appeared on the 5th day and faded within 3-4 days. Fever, chills, headache, myalgia, lymphadenopathy and other minor clinical manifestations were algo recorded, and generally persisted for from 2-5 days. Leucopenia was a constant finding in alI cases. Mild albuminuria was seen in four of 25 patients, and slight thrombocytopenia was seen in 10 of 20 cases. The fact that viremia levels higher than 5.0 loglJ1.0 ml of blood were recorded in 10 patients raises the possibility that man may be an amplifying host in the MA Y vírus cycle. The MA Y vírus illness, as seen in Belterra, has clínical features similar to those observed ín persons ínfected with chikungunya vírus