A study of the host selection patterns of the mosquitoes of the Kisumu area of Kenya

The results of 12,168 precipitin tests on blood meals of mosquitoes of the Kano Plain caught by a variety of catching techniques indicate that to gain an accurate overall picture of feeding patterns both the indoor and the outdoor biotope must be sampled. CDC light traps operated inside houses and Monkswood type light traps operated under the outside eaves of houses were found to collect larger numbers of blood fed specimens from a wider range of species than battery driven aspirators collecting from natural resting sites. The results indicated that 7 mosquito species entered houses to bite man in appreciable numbers in the Kisumu area. These were Anopheles gambiae s.l., A. funestus, A. pharoensis, Mansonia uniformia, M. africana, Culex antennatus, and C. univittatus. Eight mosquito species were found to bite man and domestic animals in the outdoor biotope in large numbers. These were: A. pharoensis, A. ziemanni, M. uniformis, M. africana, C. antennatus, C. univittatus, Aedes circumluteolus, and Ae. ochraceus. From an epidemiological point of view, species with a narrow range of hosts are most likely to be of importance as vectors of parasitic diseases such as malaria and into this category fall the major man biting anophelines A. gambiae and A. funestus. Those mosquito species which switch from one group of hosts to another according to local circumstances are most likely to be involved in arbovirus transmission and in this group the following species must be considered: A. pharoensis, A. ziemanni, M. uniformia, M. africana, C. antennatus, C. univittatus and Ae. circumluteolus.

Arbovirus infections in Sarawak, October 1968-February 1970: GETAH virus isolations from mosquitoes

14 strains of Getah virus were isolated from a variety of mosquito species collected in Sarawak between October 1968 and February 1970. Ten strains were isolated from C. tritaeniorhynchus 7 of them at K. Tijirak. Single strains were isolated from C. gelidus, C. pseudovishnui, M. bonneae/dives and Aanopheles species. 6 of the isolates were obtained in October 1968 when Japanese encephalitis, Tembusu and Sindbis viruses were also very active. The available evidence suggest that Getah virus in Sarawak is maintained in a cycle similar to that of Japanese encephalitis virus and involves C. tritaeniorhynchus, C. gelidus and domestic pigs.

Endemic paragonimiasis in Africa

Human paragonimiasis has been recorded in 4 West African countries but there is clear evidence of endemicity only in certain parts of Nigeria and Cameroon. In Nigeria, the dominant parasite species is Paragonimus uterobilateralis, while in Cameroon it is P. africanus. Both the fresh water crab Sudanonautes africanus and the land crab S. aubryi are proved vectors in Nigeria. Epidemiological studies using Paragonimus skin tests suggest an infection rate of between 5% and 10% in some endemic areas. African paragonimiasis, like its Asian counterpart, responds well to treatment with bithionol.