Evidence through crossmating experiments of a species complex in Anopheles pseudopunctipennis sensu lato: a primary malaria vector of the American continent.

Crossmating experiments were conducted to determine if postmating reproductive barriers are involved in the maintenance of genetic divergence among populations of Anopheles pseudopunctipennis sensu lato, a primary malaria vector of the American continent. Reciprocal crosses were conducted between colony and wild strains from Mexico, Bolivia, and Peru. Hybridization experiments revealed unidirectional male/female hybrid sterility in crosses between Mexican females and South American males. The data presented provide the first evidence that genetic differences exist among geographic strains of An. pseudopunctipennis in neotropical America. There is a consistent pattern suggesting the presence of at least two allopatric sibling species. One species occurs in central Mexico, the other in the South American Andean Cordillera.

Exoerythrocytic development of Plasmodium gallinaceum sporozoites in a chicken fibroblast cell line and inhibition of the cell invasion by specific anti-sporozoite monoclonal antibodies.

Cultivation of the Plasmodium gallinaceum exoerythrocytic forms from sporozoites was attempted in three different cell lines: HEPG2-A16 (from a human hepatoma), VERO (monkey kidney epithelial cells) and SL-29 (chicken embryo fibroblast cells). The sporozoites invaded all three cells types but their development into exoerythrocytic forms occurred only in the SL-29 cells. In the presence of specific monoclonal antibodies against the major circumsporozoite protein, there were varying degrees of inhibition of parasite invasion of the SL-29 cells. Of seven monoclonal antibodies tested, two completely inhibited cell invasion at high concentrations and caused intense inhibition at concentrations as low as 2.5 micrograms/ml, four caused intense inhibition at these various concentrations, and one had no effect on sporozoite invasion.

[Genetic evidence of a species complex in Anopheles pseudopunctipennis pseudopunctipennis]. / Evidencia genética de un complejo de especie en Anopheles pseudopunctipennis pseudopunctipennis.

In light of inconsistencies in the pattern of malaria transmission within geographical areas inhabited by Anopheles pseudopunctipennis pseudopunctipennis, a study was carried out to investigate the possibility that this vector constitutes a species complex. Hybrid crossing studies, electrophoretic analysis of enzyme loci, and DNA restriction analysis were conducted on mosquitoes captured at nine sites in Mexico, Bolivia, and Peru. The sterility of generations resulting from cross-mating of Mexican female mosquitoes and South American male mosquitoes; the results of electrophoretic analysis, which showed differences at two loci; and a genetic distance value of 0.13 confirmed the existence of a species complex, probably produced by allopatric speciation. It is concluded that the geographic distribution of this newly discovered species complex should be defined, in view of its potential effect on malaria control.