A Febre Maculosa no Brasil, uma revisão sistemática da literatura e o monitoramento da resistência aos acaricidas químicos do vetor Amblyomma cajennense

• Ano de defesa: 2010
• Autor(a) principal: FREITAS, Edméia de Paula e Souza
• Orientador(a): GARCÍA-ZAPATA, Marco Túlio Antonio
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Goiás
• Programa de Pós-Graduação: Mestrado em Ciências da Saúde
• Departamento: Ciências da Saúde - Medicina
• País: BR
• Palavras-chave em Português: Amblyomma cajennense; Febre maculosa; acaricidas químicos; 1. Febre maculosa 2. Amblyomma cajennense 3. Acaricidas químicos
• Palavras-chave em Inglês: Amblyomma cajennense; Brazilian spotted fever; chemical acaricides
• Área do conhecimento CNPq: CNPQ::CIENCIAS DA SAUDE
• Link de acesso: http://repositorio.bc.ufg.br/tede/handle/tde/1778

Brazilian Spotted Fever (BSF) is an acute, infectious, febrile disease of varying severity, its course ranging from asymptomatic cases to severe clinical forms with a high lethality rate. The absence of pathognomonic signs in this anthropozoonosis often results in late diagnosis, thereby serving as a stimulus for investigators to focus their attention on the weakest link of its epidemiological chain, the vector. In Brazil, the principal vector of Rickettsia rickettsii, the etiological agent of spotted fever in the New World, is the ixodid tick Amblyomma cajennense. In the present study, a systematic literature review was performed to search for publications on the epidemiology of BSF in the country. With the objective of improving control of the vector, its resistance to the principal acaricides applied against this tick was monitored. The systematic literature review was performed by searching for scientific papers dealing with BSF in the Cochrane Library, LILACS, MEDLINE and SciELO databases, using the keywords Amblyomma cajennense, Brazilian spotted fever and Rickettsia rickettsii. The search included articles published in English and Brazilian Portuguese that contained these keywords. To evaluate susceptibility and resistance to the synthetic acaricides, larvae had to be obtained from engorged female specimens of A. cajennense collected from naturally infested horses that had been free of acaricidal residue for at least 45 days, on farms belonging to five municipalities of the state of Goiás (Caldas Novas, Hidrolândia, Goiás, Terezópolis and Goiânia). The larvae were exposed to different concentrations of 12 commercially available acaricidal formulations using the larval packet test (LPT). The possible development of resistance of adult specimens of A. cajennense to the pyrethroid deltamethrin, the principal acaricide on the market in Goiás for the control of ticks in the region, was also evaluated. Unfed adult male and female specimens of A. Cajennense were collected on leaves of bushes along a nature trail in the municipality of Caldas Novas, Goiás, Brazil. They were immersed in different concentrations of deltamethrin and then placed in contact with filter paper impregnated with the substance. The control groups were exposed to distilled water alone. The bioassays were performed in quadruplicate at a temperature of 27oC, relative air humidity >80% and 12-hour light/dark cycles. From the systematic literature review, it was found that there are no records or even systematic studies of BSF in Brazil up to the present moment and the number of cases reported in the literature is lower than the figures published by the health surveillance authorities of the Ministry of Health. The data collected in this review should serve to stimulate investigators to design new studies and carry out further work, since the distribution of this disease may be more widespread than is currently supposed. Results from the bioassays showed a mean percentage of mortality ( ) of 72.6% of the adult specimens after 24 hours of exposure to the dose of deltamethrin prescribed by the manufacturer, characterizing a status of resistance to deltamethrin. The males were found to be more susceptible to this pyrethroid compared to the females. of 82%, 89%, 89.6% and 90% of the larvae were obtained, respectively, with deltamethrin, cypermethrin + piperonyl butoxide, amitraz and permethrin, characterizing a status of probable resistance of the larvae to these acaricides. The combination of cypermethrin with citronellal and with piperonyl butoxide did not significantly affect the lethal capacity of this pyrethroid against the larvae of this vector. Significant mortality was not found in the control groups (p = 0.05). These results encourage new studies to be conducted to develop alternative methods of integrated control of this vector that would be more effective and have less harm on the environment.