COSTA, V. M. M.; http://lattes.cnpq.br/1216396474248489; COSTA, Valéria Medeiros de Mendonça.
Resumo:
This thesis contains three articles on the epidemiology of tick fever in the semiarid
region of Paraíba. The first chapter is an article that describes the occurrence of
outbreaks of tick fever in the semiarid region of Paraiba, 18 of anaplasmosis by
Anaplasma marginale, two of babesiosis by Babesia bigemina, two by unidentified
Babesia and two by mixed infection with Anaplasma marginale and Babesia sp. The
outbreaks were concentrated at the end of the rainy season and early dry season each
year. Twenty two occurred in adult cattle and two in of calves of approximately 11
months-old. Two outbreaks occurred in Nelore cattle, one in Gir, and the remaining 21
occurred in animals of the Holstein or Brown Swiss breeds or crosses of these breeds
with Zebu cattle. In the second chapter we investigated the seroprevalence of A.
marginale, B. bigemina, B. bovis and T. vivax in cattle, as well as the risk factors for
these infections. The presence of antibodies in the serum of animals was detected by
indirect immunofluorescence (IFA), using specific antigens. Mean values for farm
seroprevalence was 15.0% (0-75%) for A. marginale, 9.5% (0-40%) for B. bigemina,
and 26.9% (0 to 73.7%) for B. bovis. In the third chapter the incidence of natural
infection by A. marginale, B. bovis and B. bigemina in calves was monitored each 14
days from one to 12 months-old in 5 farms in the semiarid region of Paraíba. By
polymerase chain reaction (PCR), the incidence of A. marginale infections were 0%,
83.3%, 85.7%, 100%, and 100%. The incidence of B. bigemina infections were 12.5%
and 85.7% in two farms. Infection with B. bovis was observed only in one farm with
incidence of 42.8%. By the detection of antibodies by the IFA the incidence of
infections by A. marginale in 5 farms were, respectively, 0%, 50%, 42.8%, 14.3% and
28.6%. Seropositivity to B. bigemina and B. bovis was found in only two farms, with
incidences of 57.1% and 71.4%, respectively. It is concluded that the semiarid region of
Paraíba is of enzootic instability for tick fever.