The ecological characteristics of Anopheles mosquitoes associated with low malaria transmission in Siwa oasis, Egypt.

The ecology of Anopheles sergentii and An. multicolor was investigated over eight months to examine the entomological factors maintaining the low Plasmodium vivax transmission in Siwa oasis. The two species were encountered as larvae while the dominant species, Anopheles sergentii was also collected as adults. Breeding sites were characterized for the two species in six localities. Larvae of both species were common during June and November. In Bahi El Din as an indicator village with a higher endemicity, An. sergentii females were endophilic but more common inside animal sheds than in houses, attracted more to donkey-baited traps than to human hosts, more endophagic as human biters and were more common in May/June and November. Female survivorship was higher in November than in the other months. Vector potential of An. sergentii was predicted and revealed that the species characteristics (low human contact, short survival and zoophilic feeding behavior) are responsible for maintaining such low and unstable malaria in Siwa oasis.