Hostname: page-component-78c5997874-xbtfd Total loading time: 0 Render date: 2024-11-06T11:54:05.216Z Has data issue: false hasContentIssue false
  • English
  • Français

DDT resistance in Xenopsylla brasiliensis, the common plague vector in Tanzania

Published online by Cambridge University Press:  19 September 2011

B. S. Kilonzo
B. S. Kilonzo
Affiliation:
National Rodent Control and Research Institute, Box 3047, Chuo Kikuu, Morogoro, Tanzania
Get access

Abstract

Wild-caught Xenopsylla brasiliensis from Kibwawa village, Chunya District, in south-west Tanzania were colonised in the laboratory and their offsprings used for determining the baseline susceptibility levels of the strain to DDT. A total of 120 fleas were tested with each concentration of DDT, using the techniques described by the WHO Expert Committee on Insecticides (1970).

Several filial generations were selectively raised, using DDT as a selection pressure. They were tested with various concentrations of the insecticide and their dosage–mortality regression lines compared with that of their parents.

About 5% of the parental generation (normal population) survived 1 hr exposure to 4% DDT. The LC50 of this population was 0.79% DDT. The mortality rates of the successive filial generations decreased gradually; their dosage–mortality regression lines moved to the right; and the slopes of these lines decreased. LC50s of F1, F2 and F3 were 1.6, 1.9 and 3.1% DDT, respectively. The highest DDT concentration (4%) killed 21.1 and 18.3%, of F4 and F5, respectively.

It was generally concluded that DDT resistance was present in the population, and that the selection pressure (DDT) was responsible for increasing the level of this resistance in the laboratory.

Keywords

DDT resistancefleaplagueselection pressure
Type
Research Articles
Information
International Journal of Tropical Insect Science , Volume 6 , Issue 1 , February 1985 , pp. 111 - 114
Copyright
Copyright © ICIPE 1985

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Brown, A. W. A. and Pal, R. (1971) Insecticide Resistance in Arthropods, 2nd edn, pp. 68–73 and 246–251. World Health Organisation, Geneva.Google ScholarPubMed
Busvine, J. R. and Pal, R. (1969) The impact of insecticide resistance on control of vectors and vector-borne disease. Bull. Wld Hlth Org. 40, 731.Google Scholar
Hopkins, G. H. E. (1949) Report on Rats, Fleas and Plague in Uganda, p. 32. Government Printer, Entebbe.Google Scholar
Kilonzo, B. S. (1976) A survey of rodents and their flea ectoparasites in north-eastern Tanzania. E. Afr. J. med. Res. 3, 117.Google Scholar
Krishnaswami, A. K., Krishnamurthy, B. S., Ray, S. H., Sigl, N. N. and Chandrahas, R. K. (1963) Investigation on plague in Kolar District (Mysore State): Part II. Rats and rat-fleas. Ind. J. Malar. 17, 193.Google Scholar
Lund, M. (1977) Report on DANIDA Consultantship Concerning Rodent Problems in Chunya District, Mbeya Region, Tanzania. An unpublished document presented to the Ministry of Agriculture, Dar es Salaam, November, 1977.Google Scholar
Msangi, A. S. (1968) Observations on the endemicity of plague in Tanzania. Ph.D. thesis, Univ. of London.Google Scholar
Msangi, A. S. (1975) The surveillance of rodent populations in East Africa in relation to plague endemicity. Dar es Salaam Univ. Sci. J. I, 8.Google Scholar
Roberts, J. I. (1950) The transmission of plague in Kenya. J. trop. Med. Hyg. 53, 80.Google ScholarPubMed
Smith, A. (1959) The susceptibility to Dieldrin of Pulex irritans and Pediculus humanus corporis in the Pare area of North-East Tanganyika. Bull. Wld Hlth Org. 21, 240.Google ScholarPubMed
Taylor, K. D. (1976) An Outline of the Rodent Pest Problem in Tanzania. Unpublished document on a two week visit in 1976. Presented to the Ministry of Agriculture, Dar es Salaam, Tanzania, November, 1976.Google Scholar
WHO (1970) World Health Organisation Technical Report Series No. 443. Seventh report of the Expert Committee on Insecticides: Insecticide resistance and vector control, Geneva, pp. 100–104.Google Scholar
WHO (1980) World Health Organisation Technical Report Series No. 655. Expert Committee on Vector Biology and Control: Resistance of vectors of diseases to pesticides, Geneva, pp. 12 and 78.Google Scholar