Culicifacies Species Research Articles

Susceptibility of species A, B, and C of Anopheles culicifacies complex to Plasmodium yoelii yoelii and Plasmodium vinckei petteri infections.

The comparative susceptibilities of colonized species A, B, and C of Anopheles culicifacies complex and Anopheles stephensi were determined for 2 rodent malaria parasites Plasmodium vinckei petteri and Plasmodium yoelii yoelii. All the 3 members of the complex were found to support complete sporogony with varying success. Controls, A. stephensi, become readily infected, with >70% developing oocysts. Of the test groups, species A had the highest percentage of mosquitoes with oocysts (>25%) and sporozoites (>15%). Anopheles culicifacies species B were least susceptible; less than 10% had oocysts and sporozoites in the salivary glands. The results demonstrate that A. culicifacies species A is most susceptible and species B is least susceptible to infections with both the parasites.

Comparative susceptibility of different members of the Anopheles culicifacies complex to Plasmodium vivax

Three colonized species of the Anopheles culicifacies complex (species A, B and C) were compared with Anopheles stephensi (control) for susceptibility to Plasmodium vivax. In feeding experiments involving over 400 paired comparisons, the mean number of oocysts, oocyst rate and sporozoite rate were found to be significantly different. Of the test groups, species A had the highest percentage of mosquitoes with oocysts (>60%) and sporozoites (>50%). An. culicifacies species B were least susceptible, less than 5% had oocysts and less than 2% had sporozoites in the salivary glands. The results are discussed in the light of the vectorial potential of the members of the An. culicifacies complex observed in field studies.

Susceptibility of Anopheles culicifacies species A and B to Plasmodium vivax and Plasmodium falciparum as determined by immunoradiometric assay

We have used a two-site immunoradiometric assay and species-specific antisporozpite monoclonal antibodies to determine the relative roles that sibling species A and B of the Anopheles culicifacies complex play in malaria transmission in western Uttar Pradesh, India. The results unequivocally establish species A as the primary vector of both Plasmodium vivax and P. falciparum in this area. Our results indicate active transmission of P. vivax from May to October and of P. falciparum from August to December. The identification of species A as the primary malaria vector in northern India will now allow suitable malaria control strategies to be designed.

X-linkage of malic enzyme in Anopheles culicifacies species B.

A survey for malic enzyme (Me) in laboratory strains of species A and species B of Anopheles culicifacies had uncovered two electrophoretic variants, slow and fast, in two strains of species B. Genetic analysis revealed the two variants to be codominant alleles segregating at a locus, Me, which is sex linked. Because of the XX-XY sex determining mechanism, in F1 females, two electromorphs, viz., slow and fast, were observed, whereas in males only one electromorph of maternal origin was seen. Linkage experiments with another X-linked mutant, white eye (w), indicated the map distance between the two loci to be 9.52 +/- 0.86.

Vector incrimination studies and observations on species A and B of the taxon Anopheles culicifacies in Pakistan

Studies on anopheline mosquitoes in selected villages of Punjab Province, Pakistan have incriminated Anopheles culicifacies species A as the primary malaria vector. Although An. stephensi and An. subpictus showed higher immediate gut infection rates, estimations of relative abundance, age structure and survivorship, and observations of late gut and salivary gland infection rates suggested that neither species was a major vector in these villages. A survey of An. culicifacies populations detected the presence of both species A and B in several localities in Pakistan. Laboratory investigations demonstrated that both species are capable of supporting the extrinsic cycle of Plasmodium vivax. No recombination was observed between X-linked loci in species A/species B hybrid females; however, recombination was observed between loci in chromosome 2. Allelic tests between the X-linked white eye locus in species A and an X-linked white eye mutant in species B showed that the two loci are not allelic.