ABSTRACT
The Oropouche virus (OROV; Bunyaviridae, Orthobunyavirus) is one of the most important arboviruses that infect humans in Northern
South America, particularly in the Amazon region, causing an
arboviral disease termed Oropouche (ORO) fever.26 Between 1961
and 2007, several outbreaks were reported in different urban areas
of Para´ (Bele´m, Santa Isabel, Castanhal, Santare´m, Oriximina´, Serra
Pelada, Bragantina zone-Igarape´ Ac¸u, Maracana˜, and Magalha˜es
Barata municipalities), Amazonas (Manaus, Novo Aira˜o, and Barce-
los), Acre (Xapuri), Amapa´ (Mazaga˜o), Maranha˜o (Porto Franco),
Tocantins (Tocantino´polis), and Rondoˆnia (Ariquemes and Oro
Preto D’Oeste) states.3,5,13,20,26,31,32,34 Molecular studies recently
conducted have demonstrated the circulation of at least three major
OROV lineages in the Brazilian Amazon region (genotypes I, II,
and III). The genotypes I and II are more frequently detected
in the western and eastern Amazon, respectively. The genotype
III, previously recognized only in Panama, was recently described
in the southeast region of Brazil. The association of molecular
and epidemiological data has contributed substantially to the
genetic characterization of OROV strains, isolated during different
outbreaks in the past four decades.3,15,29 In addition, it provided
a better understanding of its molecular epidemiology with respect
to emergence of new lineages and the dynamics of the evolution of
these arboviruses in the Americas, principally in the Amazon region.
In the Brazilian Amazon region, the ORO fever is considered themost
frequent arboviral disease that affects humans, after dengue, and
is characterized by epidemics of acute febrile illness accompanied
mainly by headache, arthralgia, myalgia, photophobia, and other
systemic manifestations. More rarely, some patients can present a
clinical picture of aseptic meningitis or even meningoencephalitis.
Interestingly, the symptoms of ORO fever commonly reappear a few
days after the end of the first febrile episode. However the symptoms
usually are less severe. Patients generally recovered completely
without sequels, even in the more severe cases.25
