RESUMO
The strategy for the control of schistosomiasis has shifted from one directed towards the interruption of transmission to one of reducing morbidity. As a consequence of this change, it appears prudent to reassess the role of the malacologist and malacology and identify the future direction to be taken by the discipline. The present paper addresses these concerns; first, by reviewing the role of the snail-hosts in the epidemiology and control of schistosomiasis, and, secondly, by suggesting areas for future study. The possible application of newer methods in biotechnology for the resolution of malacological problems are discussed.
Assuntos
Vetores de Doenças , Controle de Pragas , Esquistossomose/prevenção & controle , Caramujos , Animais , Interações Hospedeiro-Parasita , Caramujos/classificaçãoRESUMO
A simple and rapid method for differentiating the sibling species Biomphalaria tenagophila and Biomphalaria occidentalis by agarose gel electrophoresis (AGE) is described. Snail hemolymph is used as the test sample and the red coloration of the hemoglobin fraction permits visualization of the migration patterns without resorting to specific stains. Moreover, hemolymph samples may be obtained without killing the snail, thus permitting its use for other studies or for breeding.
Assuntos
Biomphalaria/classificação , Hemoglobinas/análise , Hemolinfa/análise , Animais , Eletroforese em Gel de Ágar , Feminino , MasculinoRESUMO
Observacoes malacologicas relacionadas a epidemiologia e transmissao de esquistossomose foram feitas na comunidade rural de Castro Alves, Estado da Bahia. Sao apresentados os tipos e natureza dos habitats aquaticos os lugares de contacto com agua da populacao,assim como a distribuicao, bionomica e nivel de infeccao de planorbideos hospedeiros. Ambos B. glabrata e B. straminea foram encontrados na area, apesar de que somente o primeiro tenha sido encontrado infectado com proporcoes de ate 22,8%. A reproducao de planorbideos parece ocorrer durante todo o ano,porem o periodo de maior fecundidade ocorreu em outubro continuando ate janeiro ou fevereiro. Foi observado que B. glabrata e capaz de resistir a periodos ocasionais de seca que ocorrem na area e refazer rapidamente a populacao original de seus habitats apos esses periodos. Essas observacoes podem ser uteis para o planejamento de programas de controle da esquistossomose nessa area
Assuntos
Biomphalaria , Saúde da População Rural , EsquistossomoseRESUMO
Seventeen populations of snails (Biomphalaria glabrata) from the state of Bahia, Brazil were studied with respect to their susceptibility to infection with an allopatric strain of Schistosoma mansoni. Two of the populations were from the city of Salvador, 3 from other sites in Bahia, and 12 from habitats in the municipio Castro Alves. Our data show that the Bahian snail populations are extremely variable in their susceptibility to an allopatric strain of S. mansoni and that the phenomenon is not associated solely with distantly separated strains, but is present, as well, in adjacent populations situated in a restricted geographic region. Of the 6 populations found to be completely refractory to infection when exposed at a size of 5--7 mm, only 2 were refractory when exposed at 5--12 days of age. It is suggested that the variability to infection displayed by populations in a restricted geographic area may be explained by assuming that the Founder Principle was operative.