To follow up on the outbreak of bat-transmitted human rabies detected in the city of Portel, state of Pará, Brazil, in January 2004, the last report on 8 April indicates that 8 cases have been confirmed since our update of 2 April, bringing the total to 13 cases of confirmed human rabies. Another 4 people are considered suspected cases (see Table 1), of which 2 have died. Test results will be available shortly.

Among the new confirmed cases, the first occurred on 2 March (instead of 4 March, as indicated in last week’s update) and the last on 1 April (instead of 26 March).

This situation constitutes the largest reported outbreak of human rabies transmitted by bats in the entire country. The causes of this extremely rare event are currently being investigated by the Department of Health of the state of Pará, the Department of Health Surveillance and the state Department of Agriculture. The bat attacks occurred mainly during the months of September and October 2003. In the meantime, these episodes have been frequent in the rural area of the Acuti Pereira River, where the affected persons reside. Initial evaluations indicate the existence of more than one colony of bats in the affected localities.