Salinity tolerance of Anopheles farauti Laveran sensu stricto.

To assess the salt tolerance of the malaria vector Anopheles farauti sensu stricto, larvae were collected from a freshwater environment on the outskirts of Honiara, Solomon Islands and placed in trays containing water with salinity varying from freshwater to seawater. Dead larvae and pupae and emerged adults were recorded and preserved. Most adults and nearly half of the larvae and pupae were then subjected to DNA analysis for species identification. No adult An. farauti emerged after prolonged immersion of larvae in undiluted seawater (3.5% salinity), although temporary immersion before pupation was compatible with survival. Salinities of up to 2.2% to 2.5% were compatible with good survival and adult emergence, at least from fourth instars. The results suggest that higher salinities may slow larval development and show that mortality at a given salinity is not uniform.

Malaria in Honiara, Solomon Islands: reasons for presentation and human and environmental factors influencing prevalence.

During February and March 1995, out-patients attending health clinics and the Central Hospital in East Honiara, Guadalcanal, Solomon Islands, were surveyed with the aim of determining factors influencing the differing rates of malaria, the proportion of transmission occurring within the town, and the reasons for presentation. Three hundred and nine adult patients, who were sick and had blood smears taken, were asked about their general knowledge of malaria transmission. Of those interviewed, 120 were visited at their home in East Honiara, to determine variables. EpiInfo 5.1 was used in analysis. A history of fever alone was not a good indicator of parasitemia. Most precautions, including bed nets, window screens and personal precautions were of little benefit. Significant protection was afforded individuals and families with indoor kitchens. Patients not completing their antimalarial treatment fared worse in terms of parasitemia and malaria history. Most malaria/parasitemia was indigenous to Honiara. Many patients had a good knowledge of malaria transmission and mosquitos, but this did not translate into a lower rate of parasitemia or malaria.

Malaria in Honiara, Solomon Islands: vector studies.

Adult and larval specimens of anopheline mosquitos were collected throughout eastern Honiara during a study into risk factors for malaria illness in adults. Species identification was by morphology, DNA probes and by PCR. Only Anopheles farauti s.s. were identified from part-night landing catches carried out from 1900 to 2200 hours. Most mosquitos attracted to humans were culicines. The majority of anophelines (85%) were captured between 1900 and 2000 hours. An. farauti s.s. larvae were most common but one An. farauti No. 7, and ten An. punctulatus larvae were also collected.