Biological and morphological characteristics of Schistosoma mansoni from Ribeira Valley, State of São Paulo, Brazil: I - susceptibility of Biomphalaria tenagophila snail to sympatric S. mansoni strain Características biológicas e morfológicas de cepa paulista de Schistosoma mansoni do Vale do Ribeira: I - suscetibilidade de Biomphalaria tenagophila do Vale do Ribeira, SP, a cepa simpátrica de Schistosoma mansoni

• Published in: Revista do Instituto de Medicina Tropical de São Paulo
• Main Authors: Ana Cristina Figueiredo, Luiz Candido de Souza Dias, Eliana Heiser de Freitas Marques
• Format: Article in Journal/Newspaper
• Language: English
• Published: Universidade de São Paulo (USP) 1992
• Subjects: Schistosoma mansoni; Biomphalaria tenagophila; Experimental susceptibility; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic; Toledo
• Online Access: https://doi.org/10.1590/S0036-46651992000300003; https://doaj.org/article/a405ed4646d84670a2802ef4ee7a5a6c

In the São Paulo State, Brazil, where the Biomphalaria tenagophila is the intermediate host, the Ribeira Valley is an important endemic schistosomiasis mansoni area. During last eleven years there has been intense control measures focusing on schistosomiasis. The efforts have been concentrated in the municipalities of Pedro de Toledo and Itariri. We determined the susceptibility of B. tenagophila to sympatric strain of S. mansoni, both recently isolated from Itariri field. In 1988, this strain was isolated and maintained in the experimental model: Swiss mice - sympatric B. tenagophila. The second generation of the worm was evaluated. The snail were divided in the three groups of 60 snails each. One group was exposed to 1 miracidium and other to 10. The third group was the control. The mortality and the shedding of cercariae were checked during 78 days. After that, the positive snails were observed until they ceased to shed cercariae. The exposed molluscs showed mortality rates of 23% and 31% and infection indexes were of 8% and 60% to 1 and 10 miracidia respectively. The mortality was of 22% in the control group. The periods of shedding cercariae in the two groups were 82 and 104 days. We can conclude that B. tenagophila is an effective intermediate host to the sympatric strain of S. mansoni sympatric strain Dentre as regiões do Estado de São Paulo, onde Biomphalaria tenagophila é hospedeira intermediária, o vale do Ribeira é área endêmica da esquistossomose. Nos últimos onze anos a endemia vem sendo intensamente controlada no vale, principalmente, nos municípios de Pedro de Toledo e Itariri. Estudamos a suscetibilidade de B. tenagophila de Itariri à linhagem simpátrica de Schistosoma mansoni, isolada do campo em 1988 e mantida no laboratório em camundongos suiço e B. tenagophila. Estudou-se a 2ª geração do trematódeo. Constituiram-se 3 grupos de 60 moluscos cada, sendo um grupo exposto a um miracídio e outro a 10 e um grupo controle não infectado. Observou-se mortalidade e eliminação de cercárias durante 78 ...