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The influence of individual, social group and household factors on the distribution of Ascaris lumbricoides within a community and implications for control strategies

Published online by Cambridge University Press:  06 April 2009

Melissa Haswell-Elkins
Affiliation:
Parasite Epidemiology Research Group, Department of Pure and Applied Biology, Imperial College, University of London, Prince Consort Road, London SW7 2BB
D. Elkins
Affiliation:
Parasite Epidemiology Research Group, Department of Pure and Applied Biology, Imperial College, University of London, Prince Consort Road, London SW7 2BB
R. M. Anderson
Affiliation:
Parasite Epidemiology Research Group, Department of Pure and Applied Biology, Imperial College, University of London, Prince Consort Road, London SW7 2BB

Summary

The distribution of Ascaris lumbricoides within a community was examined at an initial mass anthelmintic treatment programme (January 1984) and following an 11-month period of reinfection (November 1984). Similar patterns of the negative binomial parameter k (an inverse measure of parasite aggregation) and the proportion of parasites within the most heavily infected quartile of the community were recorded at the two dates. The pattern of parasite aggregation within individuals, measured by parameter k, appears to be a stable characteristic of this host-parasite relationship. Significant variation in the intensity of infection was observed between households in the community. The number of family members living in the house strongly influenced the mean Ascaris burden and proportion of relatively heavy infections within adults and children. This finding suggests that the density of people in a house positively influences the frequency of exposure to infective stages of Ascaris, which in turn plays a major role in determining which individuals will harbour heavy infections. Positive correlations were recorded between the initial and reinfection burdens of individuals, relative to others in the community. The correlations were strongest in the youngest and oldest age groups and were more frequently significant among age-stratified groups of females, compared to males. A comparative examination of hypothetical treatment strategies suggests that for Ascaris infections in this community, targetting age groups with anthelmintic treatment would probably be more cost-effective in the long term in reducing the abundance of this parasite than selective treatment of individually identified heavy infections.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1989

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References

Anderson, R. M. (1986). The population dynamics and epidemiology of intestinal nematode infections. Transactions of the Royal Society of Tropical Medicine and Hygiene 80, 686–96.CrossRefGoogle ScholarPubMed
Anderson, R. M. & May, R. M. (1985). Helminth infections of humans: mathematical models, population dynamics and control. Advances in Parasitology 24, 1101.CrossRefGoogle ScholarPubMed
Anderson, R. M. & Medley, G. F. (1985). Community control of helminth infections of man by mass and selective chemotherapy. Parasitology 90, 629–60.CrossRefGoogle Scholar
Beaver, P. C. (1952). Observations on the epidemiology of ascariasis in a region of high hookworm endemicity. Journal of Parasitology 38, 445–53.CrossRefGoogle Scholar
Bliss, C. I. & Fisher, R. A. (1953). Fitting the negative binomial distribution to biological data. Biometrics 9, 176200.CrossRefGoogle Scholar
Bundy, D. A. P., Cooper, E. S., Thompson, D. E., Didier, J. & Simmons, I. (1988). Epidemiology and population dynamics of Ascaris lumbricoides infection in the same community. Transactions of the Royal Society of Tropical Medicine and Hygiene 81, 987–93.CrossRefGoogle Scholar
Chai, Y. Y., Seo, B. S., Lee, S. H. & Cho, S. Y. (1983). Epidemiological studies on Ascaris lumbricoides reinfection in rural communities in Korea. II. Age-specific reinfection rates and familial aggregation of the reinfected cases. Korean Journal of Parasitology 21, 142–9.CrossRefGoogle ScholarPubMed
Croll, N. A., Anderson, R. M., Gyorkos, T. W. & Ghadirian, E. (1982). The population biology and control of Ascaris lumbricoides in a rural community in Iran. Transactions of the Royal Society of Tropical Medicine and Hygiene 76, 187–97.CrossRefGoogle Scholar
Elkins, D. B., Haswell-Elkins, M. R. & Anderson, R. M. (1986). The epidemiology and control of intestinal helminths in the Pulicat Lake region of Southern India. I Study design and pre- and post-treatment observations on Ascaris lumbricoides infection. Transactions of the Royal Society of Tropical Medicine and Hygiene 80, 774–92.CrossRefGoogle Scholar
Elkins, D. B., Haswell-Elkins, M. R. & Anderson, R. M. (1988). The importance of host age and sex to patterns of reinfection with Ascaris lumbricoides following mass anthelmintic treatment in a South Indian fishing community. Parasitology 96, 171–84.CrossRefGoogle Scholar
Forrester, J. E., Scott, M. E., Bundy, D. A. P. & Golden, M. H. N. (1988). Clustering of Ascaris and Trichuris infections within households. Transactions of the Royal Society of Tropical Medicine and Hygiene 82, 282–8.CrossRefGoogle ScholarPubMed
Hall, A. (1981). Aspects of parasitic infection and host nutrition. Ph.D. thesis, University of Cambridge.Google Scholar
Haswell-Elkins, M. R., Elkins, D. B. & Anderson, R. M. (1987 a). Evidence for predisposition in humans to infection with Ascaris, hookworm, Enterobius and Trichuris in a South Indian fishing community. Parasitology 95, 323–37.CrossRefGoogle Scholar
Haswell-Elkins, M. R., Elkins, D. B., Manjula, K., Michael, E. & Anderson, R. M. (1987 b). The distribution and abundance of Enterobius vermicularis in a South Indian fishing community. Parasitology 95, 339–54.CrossRefGoogle Scholar
Headlee, W. H. (1936). The epidemiology of human ascariasis in the metropolitan area of New Orleans, Louisiana. American Journal of Hygiene 24, 479521.Google Scholar
Keymer, A. E. (1985). Experimental epidemiology: Nematospiroides dubius and the laboratory mouse. In Ecology and Genetics of Host-Parasite Interactions (ed. Rollinson, D. and Anderson, R. M.), pp. 5576. London: Academic Press.Google Scholar
Lemly, A. D. & Esch, G. W. (1984). Population biology of the trematode Uvulifer ambloplitis (Hughes, 1927) in juvenile bluegill sunfish, Lepomis macrochirus, and large-mouthed bass, Micropterus salmoides. Journal of Parasitology 70, 466–74.CrossRefGoogle Scholar
Otto, G. F. & Cort, W. W. (1934). The distribution and epidemiology of human ascariasis in the United States. American Journal of Tropical Medicine and Hygiene 19, 657712.Google Scholar
Pennycuick, L. (1971). Frequency distribution of parasites in a population of three-spined sticklebacks, Gasterosteus aculeatus L., with particular reference to the negative binomial distribution. Parasitology 63, 389406.CrossRefGoogle Scholar
Scott, M. E. (1987). Temporal changes in aggregation: a laboratory study. Parasitology 94, 583–95.CrossRefGoogle ScholarPubMed
Seo, B. S., Cho, S. Y. & Chai, J. Y. (1979). Frequency distribution of Ascaris lumbricoides in rural Koreans with special reference to the effect of changing endemicity. Korean Journal of Parasitology 17, 105–13.CrossRefGoogle Scholar
Thein-Hlaing, (1985). Ascaris lumbricoides in Burma. In Ascariasis and its Public Health Significance (ed. Crompton, D. W. T., Nesheim, M. C. and Pawlowski, Z. S.), pp. 3045. London: Taylor & Francis.Google Scholar
Thein-Hlaing, Than-Saw, Htay-Htay-Aye, Myint-Lwin & Thein-Maung-Myint, (1984). Epidemiology and transmission dynamics of Ascaris lumbricoides in Okpo village, rural Burma. Transactions of the Royal Society of Tropical Medicine and Hygiene 78, 497504.CrossRefGoogle ScholarPubMed
Thein-Hlaing, Than-Saw & Myint-Lwin, (1987). Reinfection of people with Ascaris lumbricoides following single, 6-month and 12-month interval mass chemotherapy in Okpo village, rural Burma. Transactions of the Royal Society of Tropical Medicine and Hygiene 81, 140–6.CrossRefGoogle Scholar