Submitted to: Journal of Invertebrate Pathology
Publication Type: Research Notes
Publication Acceptance Date: 2/9/2004
Publication Date: 3/2/2004
Citation: Araujo-Coutinho, C., Nascimento, E., Figueiro, R., Becnel, J.J. 2004. Seasonality and prevalence rates of microsporidia in simulium pertinax (diptera: simuliidae) larvae in the region of serra dos órgãos, Rio de Janeiro, Brasil. Journal of Invertebrate Pathology. 85:188-191. Interpretive Summary: Biting flies (mosquitoes, black flies etc.) are important transmitters of diseases to man and animals worldwide. Scientists with the Mosquito and Fly Research Unit located at the USDA/ARS Center for Medical, Agricultural and Veterinary Entomology in Gainesville, Florida, USA in collaboration with scientists at the Laboratory of Black Fly and Onchocerciasis Research, Department of Entomology, IOC/FIOCRUZ, Rio de Janerio, Brazil are developing new biologically based control strategies for biting flies. Development of new biological pesticides and/or control strategies for vector and pest flies becomes increasingly important as human populations grow and new and exotic disease agents appear. Such strategies can help prevent contamination of the environment with chemical pesticides that threaten man and contribute to a decline in biodiversity. This collaborative US and Brazilian study examines natural disease causing agents (microsporidia) from black flies in Brazil. Microsporidia are common pathogens of black flies but fundamental knowledge on their life cycles, modes of transmission and taxonomic placement are incomplete. In this investigation, we have discovered three new species of microsporidia from black flies and report on their seasonality and prevalence in natural breeding sites in Brazil. This fundamental information will enable scientists to evaluate the natural control of black flies by these pathogens and to develop complementary strategies to reduce disease transmission. This project has provided a better understanding of these control agents that have a high specificity for the vector species and can serve to reduce the use of broad-spectrum pesticides, which will result in fewer negative environmental consequences.
Technical Abstract: We describe three new species of microsporidia from the economically important black fly species Simulium pertinax in Brazil. The following species were identified as entomopathogenic microsporidia: Amblyospora sp., Polydispyrenia sp. and a Microsporidium sp. A total of 9,435 larvae were collected from the Soberbo River during the period from September 2000 to September 2001, among which 44 (0.46%) were infected by microsporidia with the following distribution: 28 (0.29%) Polydispyrenia sp.; 11 (0.11%) Amblyospora sp.; 2 (0.02%) Microsporidium sp. The Polydispyrenia sp. was most common from October through May (spring through autumn) with the Amblyospora sp. found mainly during the winter and spring (July through September). The Microsporidium sp. was found only during September 2000. A total of 10,503 larvae were collected from the Andorinhas River over the period of May 2001 to May 2002, with 214 (2.04%) infected with microsporidia. Of these, 210 (1.99%) were infected with Amblyospora sp. and 4 (0.03%) were infected by Polydispyrenia sp. The Polydispyrenia sp. was not common at this site and was mainly found during the summer. Amblyospora sp. was the most common species at this site and occurred June through November. This is the first report for the occurrence of an Ambloyospora sp.and Microsporidium sp. in. S. pertinax from Brazil.