Advertisement

Hydrobiologia

, Volume 324, Issue 2, pp 163–177 | Cite as

Aquatic snails of the Bulinus africanus group in Zambia identified according to morphometry and enzymes

  • D. S. Brown
  • D. Rollinson
Article

Abstract

The Bulinus africanus species group (Planorbidae) of freshwater snails has been reported to be represented in Zambia by two species, B. africanus (Krauss) and B. globosus (Morelet), both named as intermediate hosts for Schistosoma haematobium. Uncertainty in identification of these snails from morphology led to the present investigation, combining morphometry (shell and copulatory organ) with enzyme analysis. Observations of both kinds were made usually on the same individual snails, from collecting sites mostly in the Lusaka area or at Lake Kariba. Particular attention was given to the proportional relationship between the penis sheath and the preputium of the copulatory organ, a character used previously to distinguish B. africanus from B. globosus in south-eastern Africa. The enzyme profile MDH-1, AcP-2, PGD-1 and PGM-2 was common to all snails examined from 25 populations; GPI and HBDH were polymorphic. The enzyme data indicate that the samples represent a single species. Shell characters varied continuously. The copulatory organ was generally of the form known for B. globosus. Although the copulatory organ of a few individuals had proportions overlapping the range reported for B. africanus, the present variation was continuous and was not bimodal. It is concluded that all these specimens are conspecific and may be identified as B. globosus. Previous identifications of B. africanus from Zambia appear to need substantiation and it seems that if this species is present at all in the sampled areas, it must be uncommon. It is relevant in regard to possible strain differences within S. haematobium in Zambia, that our observations indicate that only a single species of intermediate host is involved in transmission.

Key words

Mollusca Bulinus freshwater snails taxonomy distribution Africa Zambia Schistosoma haematobium schistosomiasis 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Brown, D. S., 1966. On certain morphological features of Bulinus africanus and B. globosus and the distribution of these species in southeastern Africa. Ann. Natal Mus. 18: 401–415.Google Scholar
  2. Brown, D. S., 1980. Freshwater snails of Africa and their medical importance. Taylor & Francis, London, 487 pp.Google Scholar
  3. Brown, D. S., 1994. Freshwater snails of Africa and their medical importance. Taylor & Francis, London, 608 pp.Google Scholar
  4. Brown, D. S., G. Oberholzer & J. A. van Eeden, 1971. The Bulinus natalensis/tropicus complex in southeastern Africa: 1, Shell, mantle, copulatory organ and chromosome number. Malacologia 11: 141–170.PubMedGoogle Scholar
  5. Connolly, M., 1939. A monographic survey of the South African non-marine Mollusca. Ann. S. Afr. Mus. 33: 1–660.Google Scholar
  6. Doumenge, J. P., K. E. Mott, C. Cheung, D. Villenave, O. Chapuis, M. F. Perrin & G. Reaud-Thomas, 1987. Atlas of the global distribution of schistosomiasis. CNRS/World Health Organisation, Talence, 400 pp.Google Scholar
  7. Hamilton-Attwell, V. L. & J. A. Van Eeden, 1981. Electrophoresis of the perivitelline fluid of molluscan eggs: 5. A comparison between Bulinus africanus and B. globosus. Wetensk. Bydr. potchefstroom. Univ., B, Natuurwet. 77: 1–15.Google Scholar
  8. Hira, P R., 1969. Transmission of schistosomiasis in Lake Kariba, Zambia. Nature, London 224: 670–672.Google Scholar
  9. Hira, P. R., 1970a. Schistosomiasis at Lake Kariba, Zambia. 1, Prevalence and potential intermediate snail hosts at Siavonga. Trop. Geogr. Med. 22: 323–334.PubMedGoogle Scholar
  10. Hira, P. R., 1970b. Schistosomiasis at Lake Kariba, Zambia. 2, Transmission of Schistosoma haematobium and S. mansoni at Siavonga. Trop. Geogr. Med. 22: 335–344.PubMedGoogle Scholar
  11. Hira, P. R., 1972. Studies on schistosomiasis on the western shores of Lake Bangweulu, Zambia. E. Afr. Med. J. 49: 526–530.Google Scholar
  12. Hira, P. R., 1974. Schistosoma haematobium in Lusaka, Zambia. Trop. Geogr. Med. 26: 160–169.PubMedGoogle Scholar
  13. Hira, P. R., 1975. Seasonal population densities of snails transmitting urinary and intestinal schistosomiasis in Lusaka, Zambia. Trop. Geogr. Med. 27: 83–92.PubMedGoogle Scholar
  14. Jelnes, J. E., 1979. Taxonomical studies on Bulinus using isoenzyme electrophoresis with special reference to the africanus group on Kano plain, Kenya. Malacologia 18: 147–149.Google Scholar
  15. Jelnes, J. E., 1991. Morphometry versus classical and experimental taxonomy: a dilemma posed by studies on West African Bulinus. J. moll. Stud. 57: 297–299.Google Scholar
  16. Joubert, P. H., S. J. Pretorius, K. N. De Kock & J. A. Van Eeden, 1984. The effect of constant low temperatures on the survival of Bulinus africanus, B. globosus and Biomphalaria pfeifferi. S. Afr. J. Zool. 19: 314–316.Google Scholar
  17. Joubert, P. H., S. J. Pretorius, K. N. De Kock & J. A. Van Eeden, 1986. Survival of Bulinus africanus, B. globosus and Biomphalaria pfeifferi at constant high temperatures. S. Afr. J. Zool. 21: 85–88.Google Scholar
  18. Joubert, P. H., F. J. Kruger & S. J. Pretorius, 1990. Susceptibility of South African Bulinus africanus populations to infection with Schistosoma haematobium. Trans. r. Soc. trop. Med. Hyg. 84: 100–102.CrossRefPubMedGoogle Scholar
  19. Joubert, P. H., S. J. Pretorius & F. J. Kruger, 1991. Further studies on the susceptibility of Bulinus africanus to infection with Schistosoma haematobium. Ann. trop. Med. Parasit. 85: 253–258.PubMedGoogle Scholar
  20. Kristensen, T. K. & A. G. Christensen, 1991. Morphometry versus electrophoresis in Bulinus taxonomy — a reply. J. Moll. Stud. 57: 299–300.Google Scholar
  21. Kristensen, T. K., F. Frandsen & A. G. Christensen, 1987. Bulinusafricanus-group snails in East and South East Africa, differentiated by use of biometric multivariate analysis on morphological characters (Pulmonata: Planorbidae). Revue Zool. Afr. 101: 55–67.Google Scholar
  22. Langand, J., V. Barral, B. Delay & J. Jourdane, 1993. Detection of genetic diversity within snail intermediate hosts of the genus Bulinus by using Random Amplified Polymorphic DNA markers (RAPDs). Acta Tropica, 55: 205–215.CrossRefPubMedGoogle Scholar
  23. Machena, C. & N. Kautsky, 1988. A quantitative survey of benthic vegetation and fauna in Lake Kariba, a tropical man-made lake. Freshwat. Biol. 19: 1–14.Google Scholar
  24. Mandahl-Barth, G., 1957. Intermediate hosts of Schistosoma. African Biomphalaria and Bulinus: 2. Bulinus. Bull. Wld Hlth Org. 17: 1–65.Google Scholar
  25. Mandahl-Barth, G., 1960. Intermediate hosts of Schistosoma in Africa. Some recent information. Bull. Wld Hlth Org. 22: 565–573.Google Scholar
  26. Mandahl-Barth, G.,1965. The species of Bulinus, intermediate hosts of Schistosoma. Bull. Wld Hlth Org. 33: 33–44.Google Scholar
  27. Mandahl-Barth, G., 1968. Freshwater molluscs. Expl. hydrobiol. Bangweulu-Luapula 12: 1–68.Google Scholar
  28. Mandahl-Barth, G., 1973. Descriptions of new species of African freshwater molluscs. Proc. malac. Soc. Load. 40: 277–286.Google Scholar
  29. Mungomba, L. M., S. K. Chandiwana & H. Madsen, 1993. Schistosomiasis around Siavonga, on the shores of Lake Kariba, Zambia. Ann. trop. Med. Parasit. 87: 365–371.PubMedGoogle Scholar
  30. Rollinson, D. & R. A. Kane, 1991. Restriction enzyme analysis of DNA from species of Bulinus (Basommatophora: Planorbidae) using a cloned ribosomal RNA probe. J. moll. Stud. 57: 93–98.Google Scholar
  31. Rollinson, D. & V. R. Southgate, 1979. Enzyme analyses of Bulinus africanus group snails from Tanzania. Trans. r. Soc. trop. Med. Hyg. 73: 667–672.CrossRefPubMedGoogle Scholar
  32. Strahan, K., R. A. Kane & D. Rollinson, 1991. Development of cloned DNA probes for the identification of snail intermediate hosts within the genus Bulinus. Acta Tropica 48: 117–126.CrossRefGoogle Scholar
  33. Wright, C. A. & D. Rollinson, 1979. Analysis of enzymes in the Bulinus africanus group (Molluscs: Planorbidae) by isoelectric focusing. J. nat. Hist. 13: 263–273.Google Scholar

Copyright information

© Kluwer Academic Publishers 1996

Authors and Affiliations

  • D. S. Brown
    • 1
  • D. Rollinson
    • 1
  1. 1.Department of ZoologyThe Natural History MuseumLondonU.K.

Personalised recommendations