ABSTRACT
The group C viruses and the Guama group viruses are some of the rst viral agents isolated in the 1950s, when researchers of the Instituto Evandro Chagas, Belém, Pará, Brazil, and Rockefeller Foundation began an intense search for answers to the real cause of febrile human cases, similar to yellow fever, which occurred near the city of Belém, Pará state, northern Brazil [1]. The researchers responsible for that study concluded that the febrile cases occurred predominantly in workers brought from the northeastern region of Brazil to execute activities of deforestation, cultivation of black pepper and rubber tapping, and also in Japanese immigrants settled in small communities close to the forest. It was also observed that urban dwellers became sick when they entered the forest. Initially, ve different group C orthobunyaviruses were isolated from sera of nonimmune sentinel monkeys (Cebus apella), exposed in the Oriboca Forest, located 20 km west of Belém, after intracerebral inoculation in suckling mice (1-3 days in age).
