Hostname: page-component-8448b6f56d-cfpbc Total loading time: 0 Render date: 2024-04-19T21:55:52.562Z Has data issue: false hasContentIssue false
  • English
  • Français

Relative contribution of day-to-day and intra-specimen variation in faecal egg counts of Schistosoma mansoni before and after treatment with praziquantel

Published online by Cambridge University Press:  07 August 2001

J. UTZINGER ,
M. BOOTH ,
E. K. N'GORAN ,
I. MÜLLER ,
M. TANNER  and
C. LENGELER
J. UTZINGER
Affiliation:
Swiss Tropical Institute, PO Box, CH-4002 Basel, Switzerland Centre Suisse de Recherches Scientifiques, Abidjan, Côte d'Ivoire Princeton University, Office of Population Research, Princeton, NJ 08544, USA
M. BOOTH
Affiliation:
Cambridge University, Department of Pathology, Tennis Court Road, Cambridge CB2 1QP, UK
E. K. N'GORAN
Affiliation:
Centre Suisse de Recherches Scientifiques, Abidjan, Côte d'Ivoire UFR Biosciences, Université de Cocody, Abidjan, Côte d'Ivoire
I. MÜLLER
Affiliation:
Swiss Tropical Institute, PO Box, CH-4002 Basel, Switzerland
M. TANNER
Affiliation:
Swiss Tropical Institute, PO Box, CH-4002 Basel, Switzerland
C. LENGELER
Affiliation:
Swiss Tropical Institute, PO Box, CH-4002 Basel, Switzerland
Get access Rights & Permissions [Opens in a new window]

Abstract

There is evidence that faecal egg counts of Schistosoma mansoni vary considerably from day to day, which results in poor sensitivity of single stool readings. Intra-specimen variation of S. mansoni egg counts may also be considerable, but has previously been considered as the less important component. We quantified the relative contribution of these two sources of variation among 96 schoolchildren from an area in Côte d'Ivoire highly endemic for S. mansoni. Stool specimens were collected over 5 consecutive days, and 5 egg-counts were made in each specimen by the Kato–Katz technique. The point prevalence of the first sample was 42.7% and the cumulative prevalence after the maximum sampling effort was 88.5%. Using generalized linear mixed models we found that the presence of S. mansoni eggs in a stool sample varied much more between days than within specimens, indicating that stool sample examination over multiple days is required for accurate prevalence estimates. However, using the same approach, we found that among infected children intra-specimen variation in egg counts was 4.3 times higher than day-to-day variation. After praziquantel administration, day-to-day variation was more important than before, since most infections were very light and thus likely to be missed altogether by stool examination on a single day. We conclude that diagnostic sensitivity in high transmission areas is maximized by making several stool readings on several days, but examining 1 stool specimen several times can make reasonable estimates of infection intensity.

Keywords

schistosomiasisSchistosoma mansoniegg countday-to-day variationintra-specimen variationpraziquantel
Type
Research Article
Information
Parasitology , Volume 122 , Issue 5 , May 2001 , pp. 537 - 544
Copyright
2001 Cambridge University Press

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

ANDERSON, R. M & MAY, R. M. (1985). Helminth infections of humans: mathematical models, population dynamics, and control. Advances in Parasitology 24, 1–101.CrossRefGoogle Scholar
BARRETO, M. L., SILVA, J. T. F., MOTT, K. E. & SEHMAN, J. S. (1978). Stability of faecal egg excretion in Schistosoma mansoni infection. Transactions of the Royal Society of Tropical Medicine and Hygiene 72, 181–187.CrossRefGoogle Scholar
BARRETO, M. L., SMITH, D. H. & SLEIGH, A. C. (1990). Implication of faecal egg count variation when using the Kato–Katz method to assess Schistosoma mansoni infections. Transactions of the Royal Society of Tropical Medicine and Hygiene 84, 554–555.CrossRefGoogle Scholar
BRADLEY, D. J. (1972). Regulation of parasite populations: a general theory of the epidemiology and control of parasitic infections. Transactions of the Royal Society of Tropical Medicine and Hygiene 66, 697–708.CrossRefGoogle Scholar
BUTTERWORTH, A. E., CAPRON, M., CORDINGLEY, J. S., DALTON, P. R., DUNNE, D. W., KARIUKI, H. C., KIMANI, G., KOECH, D., MUGAMBI, M., OUMA, J. H., PRENTICE, M. A., RICHARDSON, B. A., ARAP SIONGOK, T. K., STURROCK, R. F. & TAYLOR, D. W. (1985). Immunity after treatment of human schistosomiasis mansoni. II. Identification of resistant individuals, and analysis of their immune responses. Transactions of the Royal Society of Tropical Medicine and Hygiene 79, 393–408.Google Scholar
DE VLAS, S. J., ENGELS, D., RABELLO, A. L. T., OOSTBURG, B. F. J., VAN LIESHOUT, L., POLDERMAN, A. M., VANOORTMARSSEN, G. J., HABBEMA, J. D. F. & GRYSEELS, B. (1997). Validation of a chart to estimate true Schistosoma mansoni prevalences from simple egg counts. Parasitology 114, 113–121.CrossRefGoogle Scholar
DE VLAS, S. J. & GRYSEELS, B. (1992). Underestimation of Schistosoma mansoni prevalences. Parasitology Today 8, 274–277.CrossRefGoogle Scholar
DE VLAS, S. J., GRYSEELS, B., VAN OORTMARSSEN, G. L., POLDERMAN, A. M. & HABBEMA, J. D. F. (1992). A model for variations in single and repeated egg counts in Schistosoma mansoni infections. Parasitology 104, 451–460.CrossRefGoogle Scholar
DOENHOFF, M. J. (1998). Is schistosomicidal chemotherapy sub-curative? Implications for drug resistance. Parasitology Today 14, 434–435.CrossRefGoogle Scholar
ENGELS, D., NAHIMANA, S., DE VLAS, S. J. & GRYSEELS, B. (1997b). Variation in weight of stool samples prepared by the Kato–Katz method and its implications. Tropical Medicine and International Health 2, 265–271.Google Scholar
ENGELS, D., SINZINKAYO, E. & GRYSEELS, B. (1996). Day-to-day egg count fluctuation in Schistosoma mansoni infection and its operational implications. American Journal of Tropical Medicine and Hygiene 54, 319–324.CrossRefGoogle Scholar
ENGELS, D., SINZINKAYO, E. & GRYSEELS, B. (1997a). Intraspecimen fecal egg count variation in Schistosoma mansoni infection. American Journal of Tropical Medicine and Hygiene 57, 571–577.Google Scholar
GÖNNERT, R. & ANDREWS, P. (1977). Praziquantel, a new broad-spectrum antischistosomal agent. Zeitschrift für Parasitenkunde 52, 129–150.CrossRefGoogle Scholar
GRYSEELS, B., NKULIKYINKA, L. & ENGELS, D. (1991). Repeated community-based chemotherapy for control of Schistosoma mansoni: effect of screening and selective treatment on prevalences and intensities of infection. American Journal of Tropical Medicine and Hygiene 45, 509–517.CrossRefGoogle Scholar
HALL, A. (1981). Quantitative variability of nematode egg counts in faeces: a study among rural Kenyans. Transactions of the Royal Society of Tropical Medicine and Hygiene 75, 682–687.CrossRefGoogle Scholar
KATZ, N., CHAVES, A. & PELLEGRINO, J. (1972). A simple device for quantitative stool thick-smear technique in schistosomiasis mansoni. Revista do Instituto Medicina Tropical de Sao Paulo 14, 397–400.Google Scholar
KNIGHT, W. B., HIATT, R. A., CLINE, B. L. & RICHIE, L. S. (1976). A modification of the formol-ether concentration technique for increased sensitivity in detection of Schistosoma mansoni eggs. American Journal of Tropical Medicine and Hygiene 25, 818–823.CrossRefGoogle Scholar
MARTIN, L. K. & BEAVER, P. C. (1968). Evaluation of Kato thick-smear technique for quantitative diagnosis of helminth infections. American Journal of Tropical Medicine and Hygiene 17, 382–391.CrossRefGoogle Scholar
PIT, D. S. S., DE GRAAF, W., SNOEK, H., DE VLAS, S. J., BAETA, S. M. & POLDERMAN, A. M. (1999). Diagnosis of Oesophagostum bifurcum and hookworm infection in humans: day-to-day and within-specimen variation of larval counts. Parasitology 118, 283–288.CrossRefGoogle Scholar
POLDERMAN, A. M. (1979). Transmission dynamics of endemic schistosomiasis. Tropical and Geographical Medicine 31, 465–475.Google Scholar
RATARD, R. C., KOUEMENI, L., EKANI BESSALA, M. M. & NDAMKOU, N. C. (1990). Distribution and preservation of Schistosoma mansoni eggs in stools. Journal of Tropical Medicine and Hygiene 93, 413–416.Google Scholar
SABAH, A. A., FLETCHER, C., WEBBE, G. & DOENHOFF, M. J. (1986). Schistosoma mansoni: chemotherapy of infections of different ages. Experimental Parasitology 61, 294–303.CrossRefGoogle Scholar
SCHALL, R. (1991). Estimation in generalized linear models with random effects. Biometrika 78, 719–727.CrossRefGoogle Scholar
SLEIGH, A., HOFF, R., MOTT, K., BARRETO, M., MAISK DEPAIVA, T., DE SOUZA PEDROSA, J. & SHERLOCK, I. (1982). Comparison of filtration staining (Bell) and thick smear (Kato) for the detection and quantification of Schistosoma mansoni eggs in faeces. Transactions of the Royal Society of Tropical Medicine and Hygiene 76, 403–406.CrossRefGoogle Scholar
TEESDALE, C. H., FAHRINGER, K. & CHITSULO, L. (1985). Egg count variability and sensitivity of a thin smear technique for the diagnosis of Schistosoma mansoni. Transactions of the Royal Society of Tropical Medicine and Hygiene 79, 369–373.CrossRefGoogle Scholar
UTZINGER, J., N'GORAN, E. K., ESSE AYA, C. M., ACKAADJOUA, C., LOHOURIGNON, K. L., TANNER, M. & LENGELER, C. (1998). Schistosoma mansoni, intestinal parasites and perceived morbidity indicators in schoolchildren in a rural endemic area of western Côte d'Ivoire. Tropical Medicine and International Health 3, 711–720.CrossRefGoogle Scholar
UTZINGER, J., N'GORAN, E. K., OSSEY, Y. A., BOOTH, M., TRAORÉ, M., LOHOURIGNON, K. L., ALLANGBA, A., AHIBA, L. A., TANNER, M. & LENGELER, C. (2000a). Rapid screening for Schistosoma mansoni in western Côte d'Ivoire using a simple school questionnaire. Bulletin of the World Health Organization 78, 389–398.Google Scholar
UTZINGER, J., N'GORAN, E. K., N'DRI, A., LENGELER, C. & TANNER, M. (2000b). Efficacy of praziquantel against Schistosoma mansoni with particular consideration of intensity of infection. Tropical Medicine and International Health 5, 771–778.Google Scholar
WILKINS, H. A. (1989). Reinfection after treatment of schistosomiasis infections. Parasitology Today 5, 83–88.CrossRefGoogle Scholar
WORLD HEALTH ORGANIZATION (1993). The control of schistosomiasis: second report of the WHO Expert Committee. WHO Technical Report Series No. 830. World Health Organization, Geneva.Google Scholar
WORLD HEALTH ORGANIZATION (1999). Report of the WHO Informal Consultation on Schistosomiasis Control. WHO/CDS/CPC/SIP/99.2. World Health Organization, Geneva.Google Scholar
XIAO, S. H., CATTO, B. A. & WEBSTER, L. T. (1985). Effects of praziquantel on different developmental stages of Schistosoma mansoni in vitro and in vivo. Journal of Infectious Diseases 151, 1130–1137.CrossRefGoogle Scholar
YE, X.-P., DONNELLY, C. A., ANDERSON, R. M., FU, Y.-L. & AGNEW, A. (1998). The distribution of Schistosoma japonicum eggs in faeces and the effect of stirring faecal specimens. Annals of Tropical Medicine and Parasitology 92, 181–185.CrossRefGoogle Scholar
YU, J. M., DE VLAS, S. J., YUAN, H. C. & GRYSEELS, B. (1998). Variations in fecal Schistosoma japonicum egg counts. American Journal of Tropical Medicine and Hygiene 59, 370–375.CrossRefGoogle Scholar