Skip to main content
NCBI home page
Bulletin of the World Health Organization logoLink to Bulletin of the World Health Organization
. 1966;35(3):339–356.

The ecology of Bulinus truncatus and Biomphalaria alexandrina and its implications for the control of bilharziasis in the Egypt-49 project area

B C Dazo, Nelson G Hairston, I K Dawood
PMCID: PMC2476091  PMID: 5297630

Abstract

The respective vectors of the two forms of bilharziasis in Egypt do not have the same ecological distribution. Bulinus truncatus is most abundant in large canals, and decreases in density as the water approaches and flows into drains. Biomphalaria alexandrina is most abundant in drains, and decreases in density upstream from these habitats. Both species are most abundant in the presence of aquatic vegetation, but they differ in their respective associations with the water hyacinth, Eichhornia crassipes. Biomph. alexandrina reaches maximum abundance in the presence of this plant, but Bul. truncatus is as uncommon in the absence of plants as in the presence of E. crassipes.

Calculation of life-table parameters from field data shows that, under optimum field conditions, both species can double their populations in 14-16 days. The reproductive rates of both species are greatest in March and the death rates in midsummer. The observed peak densities in May and June give a false impression of optima because of undercollection of young snails, which are most abundant in March and April.

Control operations should take advantage of the findings on population parameters. A single area-wide treatment with molluscicide in April is recommended. During the remainder of the year, search for isolated foci of snail breeding and individual treatment of these will effect large savings of chemical and will be effective in controlling the transmission of the parasites.

Full text

PDF
339

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. ABDEL-MALEK E. Distribution of the intermediate hosts of bilharziasis in relation to hydrography; with special reference to the Nile Basin and the Sudan. Bull World Health Organ. 1958;18(5-6):691–734. [PMC free article] [PubMed] [Google Scholar]
  2. ABDEL-MALEK E. Factors conditioning the habitat of bilharziasis intermediate hosts of the family Planorbidae. Bull World Health Organ. 1958;18(5-6):785–818. [PMC free article] [PubMed] [Google Scholar]
  3. BARLOW C. H., MUENCH H. Life span and monthly mortality rate of Bulinus truncatus and Planorbis biossyi, the intermediate hosts of schistosomiasis in Egypt. J Parasitol. 1951 Apr;37(2):165–173. [PubMed] [Google Scholar]
  4. BARLOW C. H. Snail ponds. J Parasitol. 1950 Oct;36(5):447–450. [PubMed] [Google Scholar]
  5. DAWOOD I. K., FAROOQ M., DAZO B. C., MIGUEL L. C., UNRAU G. O. HERBICIDE TRIALS IN THE SNAIL HABITATS OF THE EGYPT 49 PROJECT. Bull World Health Organ. 1965;32:269–287. [PMC free article] [PubMed] [Google Scholar]
  6. EL-GINDY M. S. Distribution and ecology of the snail vectors of Schistosomiasis in Egypt. J Egypt Med Assoc. 1957;40(3-4):192–204. [PubMed] [Google Scholar]
  7. PAULINI E. FIELD OBSERVATIONS ON THE UPSTREAM MIGRATION OF AUSTRALORBIS GLABRATUS. Bull World Health Organ. 1963;29:838–841. [PMC free article] [PubMed] [Google Scholar]
  8. PESIGAN T. P., HAIRSTON N. G., JAUREGUI J. J., GARCIA E. G., SANTOS A. T., SANTOS B. C., BESA A. A. Studies on Schistosoma japonicum infection in the Philippines. 2. The molluscan host. Bull World Health Organ. 1958;18(4):481–578. [PMC free article] [PubMed] [Google Scholar]
  9. SHIFF C. J. STUDIES ON BULINUS (PHYSOPSIS) GLOBOSUS IN RHODESIA. I. THE INFLUENCE OF TEMPERATURE ON THE INTRINSIC RATE OF NATURAL INCREASE. Ann Trop Med Parasitol. 1964 Mar;58:94–105. [PubMed] [Google Scholar]
  10. UNRAU G. O., FAROOQ M., DAWOOD I. K., MIGUEL L. C., DAZO B. C. FIELD TRIALS IN EGYPT WITH ACROLEIN HERBICIDE-MOLLUSCICIDE. Bull World Health Organ. 1965;32:249–260. [PMC free article] [PubMed] [Google Scholar]
  11. VAN DER SCHALIE H. Vector snail control in Qalyub, Egypt. Bull World Health Organ. 1958;19(2):263–283. [PMC free article] [PubMed] [Google Scholar]
  12. WATSON J. M. Ecology and distribution of Bulinus truncatus in the Middle East; with comments on the effect of some human activities in their relationship to the snail host on the incidence of bilharziasis haematobia in the Middle East and Africa. Bull World Health Organ. 1958;18(5-6):833–894. [PMC free article] [PubMed] [Google Scholar]
  13. YEO D. A preliminary statistical analysis of snail counts. Bull World Health Organ. 1962;27:183–187. [PMC free article] [PubMed] [Google Scholar]
  14. ZAKARIA H. Further study on the ecology of the intermediate host of Schistosoma haematobium, Bulinus truncatus Baylis. Bull Endem Dis (Baghdad) 1955 Jan;1(2):123–155. [PubMed] [Google Scholar]

Articles from Bulletin of the World Health Organization are provided here courtesy of World Health Organization

RESOURCES