[Surveillance of plague in the State of Ceará: 1990-1999].

Serological surveillance activities regarding the foci of plague in Ceará State have detected a rising number of sentinel animals with antiplague antibodies in 1995, with a peak in 1997 demonstrating an increase in the plague bacteria activities throughout all the foci investigated. From a total of 110,725 serum samples collected from rodents (7,873) and domestic carnivores (102,852) analyzed by the Hemaglutination technique (HA) for antibodies against F1 antigen of Yersinia pestis 905 samples tested positive. In these samples there were 15 rodents (4 Rattus rattus and 11 Galea spp), 720 dogs and 170 cats. Of the 652 human suspected and contact cases investigated by HA, only two were positive. A third case had a positive hemoculture for Y. pestis. The isolate is highly pathogenic for laboratory animals and showed sensitivity to the antimicrobial drugs used for plague treatment.