Macaca mulatta were found to be susceptible to infections with group C arboviruses after subcutaneous inoculation. Infections caused by Oriboca, Marituba, Murutucu, and Apeu viruses were consistent in time of onset, duration, and level of viremia. The appearance of viremia with Itaqui virus was occasionally inconsistent, and with Caraparu virus the appearance of viremia was irregular. Overt signs of systemic illness in monkeys infected with any of the group C viruses used were limited to fever, which was detected in only a few animals. Infections with these viruses appeared to be noncontagious for uninoculated monkeys that were exposed by limited contact to infected monkeys in the viremic phase. Cross-immunity was demonstrated by monkeys that recovered from one virus infection and were challenged with related heterotypic viruses.
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