Species shifting composition of the Anopheles vector in Wongsorejo district - Banyuwangi, Indonesia

Malaria’s cases have been reported to occur annually in Wongsorejo district of Banyuwangi, East Java since 2002. However, there is a significant decrease of malaria cases during these last years, which might be related to the malaria vector species shifting composition. The objective of this research was to observe some important bionomic characteristics of malaria vector Anopheles in this area from 2015 until 2020 which include species identification, blood feeding behaviour and biting preference of vector. The data collection i.e. determination of Anopheles diversity and behaviour was conducted monthly for 3-6 months annually from 2015 – 2018. In 2019-2020 we sampled irregularly to see the trend. The results showed that there were species shifting of Anopheles vectors in this area. The proportion of Anopheles (An.) sundaicus and An. subpictus, which were previously reported until 2015 as the main Anopheles species in this area, significantly decreased in 2016 - 2018. An. indefinitus & An. vagus was becoming the majority of Anopheles species. During 2019-2020, An. vagus became the main species identified in the sampling area. The predominant species of An. vagus and An. indefinitus has exophagic and zoophilic preference behaviour. Furthermore, An. indefinitus has not previously been identified as a vector for malaria, compared to An. sundaius, and An. subpictus which are well known as an important primary malaria vector on Java Island, Indonesia.

Studies on the Life-History of Aëdes (Skusea) Pembaensis (Theobald) (Diptera, Culicidae)

SummaryThe observation in Kenya that Aëdes (Skusea) pembaensis (Theo.) associates with the crab, Sesarma meinerti, was duplicated in Lumbo, on the northern coast of Mozambique. Eggs were seen abundantly on crabs inhabiting certain colonies among mangroves at the edge of a tidal estuary. Females of A. pembaensis were caught in gradually decreasing abundance at collecting sites progressively further inland from the head of the estuary, while males were almost totally confined to the breeding area. Swarms of males were not seen, and it was suspected that mating took place within crab burrows.Populations of A. pembaensis in 1959 and 1960 were approximately equivalent at Lumbo, whereas some other mosquito species with fresh-water larval stages were reduced in 1960 owing to failure of the rains. The estuarine environment, regulated by the tides, is apparently more stable than are terrestrial habitats. Cycles of A. pembaensis may therefore be less variable than among dry-land forms.Females of A. pembaensis disturbed at a crab colony were found to bite spontaneously in the day-time. Captured specimens showed a marked discrimination in biting preference for one human out of three tested. The preferred individual experienced a severe reaction to the bites, while the other two had none whatsoever.Precipitin tests indicated human beings as the only source of blood in A. pembaensis, although the method of collection probably lends bias to this observation. Eight strains of an apparently new virus were isolated from females of A. pembaensis in 1959 and four in 1960. In addition, two strains of a virus of the Bunyamwera group were isolated in 1960. The source of these viruses and their significance in A. pembaensis require further investigation.