An analysis of some factors determining the sporozoite rates, human blood indexes, and biting rates of members of the Anopheles punctulatus complex in Papua New Guinea
Burkot, T.R.; Dye, C.; Graves, P.M.
American Journal of Tropical Medicine and Hygiene 40(3): 229-234
1989
ISSN/ISBN: 0002-9637 PMID: 2929848 Document Number: 341534
In 9 villages in Madang Province, Papua New Guinea, sporozoite antigen positivity rate (SR) for Plasmodium falciparum and P. vivax, and human blood index (HBI) for 3 malaria vectors varied as follows: Anopheles faranti SR 0-2.7, HBI 0-0.45; An. koliensis SR 0.21-2.34, HBI 0-0.85; An. punctulatus SR 0.33-3.33, HBI 0.20-1.00. Variations in HBI partly explain the variations in SR. There were also variations in the ratios of people:pigs:dogs but the number of people usually outweighed the number of animals. In fact the HBI was found not to be dependent on the numbers of either dogs or pigs. There were also differences between villages in the proportion of people using bednets as well as the number of people sharing a bednet. These results and the results of periodic night-biting catches have all been subjected to sophisticated statistical treatments. The authors conclude that the HBI varied with the number of persons sharing a bednet and that it was very dependent on human biting rate (which varied inversely with the mosquito density, implying some avoidance when the density was high). Both the HBI and human biting rates were influenced by the distribution of alternative hosts relative to people.G. Davidson The degree to which members of the A. punctulatus complex feed on humans in different Papua New Guinea villages has a significant effect on Plasmodium falciparum and P. vivax sporozoite rates. Among villages, the human blood index (HBI) of the members of the complex varied with the average number of persons sharing a bednet. Although dogs are the preferred hosts by the 3 malaria vector species (A. farauti, A. koliensis and A. punctulatus), the number of dogs did not significantly affect the HBI. The HBI was dependent upon the human-biting rate, implying increased avoidance of anophelines by people relative to other hosts at times of greater mosquito numbers. Human-biting rates and HBIs were also influenced by the distribution of alternative hosts (e.g. dogs, pigs and chickens) relative to people.