グァテマラの人吸血性ブユの研究 : とくに同国南東部流行地におけるオンコセルカ症伝播との関連について

Abstract

A year-long investigation was carried out to study the relative importance of the Guatemalan blackfly species in relation to the transmission of onchocerciasis at finca (plantation) Pena Blanca situated on the southeastern part of the endemic area of San Vicente Pacaya in 1977 and 1978; as well as at two other fincas Monica Ivone and San Rafael Sumatan in the major endemic zone on the Pacific slope of the Sierra Madre in 1978. The predominant anthropophilic species was Simulium ochraceum at Pena Blance and Monica Ivone, while it was S. metallicum at finca San Rafael Sumatan. Simulium ochraceum females harboured the third-stage larvae of Onchocerca volvulus at Pena Blanca (0.33%) and at Monica Ivone (0.02%). By contrast, S. metallicum and S. callidum did not harbour any stage of larvae of this parasite, although first- and second-stage larvae indistinguishable from O. volvulus were found in these two species of blackflies at Pena Blanca (1.0 and 0.3%, respectively). The annual infective biting density (AIBD) of S. ochraceum at Pena Blance was 221,and its seasonal pattern was distinct, exhibiting high peak period during the dry season. The AIBD of the same species at Monica Ivone was 59. Simulium ochraceum was proved to be not only anthropophilic but also zoophilic when the goat was compared with man as an attractant. In conclusion, it is recommended that any control measures against the vector insect in the southeastern part of the Guatemalan endemic zones should be concentrated on S. ochraceum.