Morbidity of schistosomiasis mansoni in the highlands of Madagascar and comparison of current sonographical classification systems.

To study the morbidity of schistosomiasis mansoni in the highlands of Madagascar, a cross-sectional study examined the extent to which liver fibrosis occurred in a rural community. The Managil and the Cairo classification systems were used. A second purpose was to investigate the effect of the measurements of 2 different branches of the portal vein (either segmental or sub-segmental branches) on the resulting staging of morbidity using the Cairo classification system. In a rice farmer village, 656 inhabitants (95% of the total population) were parasitologically examined; 561 patients underwent sonographic work-up based on the Managil scoring system, and in 307 randomized patients the outer to outer diameters of both the segmental and the sub-segmental branches of the portal vein were measured and scored by the Cairo classification system. Overall prevalence of schistosomiasis mansoni in the study area in 1994 was 68.3%. Upon sonographic examination and scoring by the Managil system 23.4% of the population showed liver changes (Managil degree I/II/III, 20%/2.5%/0.9%). Measuring the sub-segmental branches only and scoring by the Cairo classification, 19% of the study population were found to have liver changes, none with severe fibrosis. By contrast, 82% were found to have liver changes (Cairo degree 1/2/3, 70%/11%/2%) when the segmental branches were measured. The diameters of the sub-segmental branches were about two-thirds of those of the segmental branches. Both the Cairo- and the Managil-examination protocols have pitfalls. Using the Cairo classification, a considerable systematic error in classifying morbidity is created by measuring different branches of the portal vein.

[Experimental study of a Malagasy strain of Schistosoma haematobium: compatibility with different Bulinus snails, potential intermediate hosts]. / Etude expérimentale d'une souche malgache de Schistosoma haematobium: compatibilité avec différents bulins, hôtes intermédiaires potentiels.

Experimental investigation on a malagasy strain of S. haematobium: compatibility with different Bulinus snails, potential intermediate hosts. A comparative experimental study of the infectivity of different Bulinus snails by a reference S. haematobium strain was made under laboratory conditions. The results support the role of Bulinus obtusispira as an intermediate host in Madagascar but some other Bulinus species could exist and play a role in the fields far away from the experimental criteria here described.

[Validation of questionnaire methods to identify Schistosoma haematobium bilharziasis hyperendemic zones in Madagascar]. / Validation de la méthode du questionnaire pour identifier les zones hyperendémiques de la bilharziose à Schistosoma haematobium à Madagascar.

Schistosomiasis is a major public health problem in Madagascar. The aim of the national control program is to reduce the morbidity in hyperendemic areas. A prospective study has been conducted in Morombe and Ampanihy to elaborate a simple method to identify Shistosoma haematobium hyperendemic communities. The study included 1,373 children from 5 to 15 years old in 17 primary schools. Moderate sensitivity and Negative Predictive Value, with high specificity and Positive Predictive Value of "blood in urine" and "Schistosomiasis" have been found. Those diagnosis values increase with age. The first symptom should be used in older children.

[Schistosomiasis mansoni infection in a hyperendemic region of midwestern Madagascar: epidemiology, morbidity and secondary effects of praziquantel treatment]. / Infection a Schistosoma mansoni dans un foyer d'hyperendemie du moyen ouest de Madagascar: épidémiologie, morbidité et effets secondaires liés au traitement par praziquantel.

The examination of 544 inhabitants (93.2% of the whole population) of a village in the middle west of Madagascar, where Schistosoma mansoni is hyperendemic and where no previous antischistosomal treatment had been delivered at a community level, showed a prevalence rate of 61.8%. The highest prevalences and the most intense infections were observed in the 10-24 age group. The egg count decreases dramatically from the age of 25. A highly significant relationship was found between recent histories of bloody diarrhoea and S. mansoni eggs excretion. Clinical examination showed a high frequency of splenomegalies (62.2% > or = stade 2 Hackett), with two modes: one in the 10-14 age group and the other in the 35-39 age group. The respective liability of S. mansoni and malaria remain to be clarified. Side effects after treatment of the entire population with praziquantel were observed in 27.2% of treated individuals. Side effects occurred mainly in infected people. A highly significant relationship was found between intensity of infection and frequency of these side effects which are essentially mild and disappear in the 24 hours.

[Evolution of Schistosoma mansoni bilharziasis in Ampefy (Lake Itasy) from 1986 to 1993]. / Evolution de la bilharziose à Schistosoma mansoni à Ampefy (Lac Itasy) de 1986 a 1993.

In 1976, 1983, 1986 to 1989 and 1993, the population of Ampefy, on the shores of lake Itasy, was invited to participate in an active detection programme of Schistosoma mansoni infection. An increase in the global prevalence was observed from 1976 (17.0%) to 1983 (40.0%). This prevalence level was then stabilized during the four years annual selective treatment (1986 to 1989) and the mean intensity of infection for positive patients fell from 393 eggs/g to 271 eggs/g and the proportion of severe infections, with a high risk of developing "hepatosplenic disease", fell from 8% to 4.2%. Selective treatment was interrupted from 1989 to 1993, during which time the global prevalence rose to 70.6% and mean intensity of infection to 594 eggs/g, with 22% of those examined classified as severely infested. This local control programme, associating active detection with annual treatment, seems effective in stabilizing prevalence and intensity of infection in spite of a regular arrival of infested, and never treated, immigrants. However, its impact throughout time is limited.

[Why compare hepatosplenic bilharziasis in six African countries with the help of ultrasonography? Presentation of a WHO project including Madagascar]. / Pourquoi comparer la morbidité de la bilharziose hépatosplénique dans six pays africains à l'aide de l'échographie? Présentation d'un projet OMS incluant Madagascar.

During a morbidity survey in two endemic foci of hepatosplenic schistosomiasis in the malagasy Hauts Plateaux (Tetikanana, 80 km East of Ambositra and Lohanosy, in the vicinity of Antananarivo), the objectives of a comparative pathology WHO project are presented. The survey in Madagascar was concurrently organized by the Ministry of Health (Bilharziasis central laboratory, DLMT), the Parasitology Unit of the local Pasteur Institute and the Medical Parasitology Institute of Bonn University, in Germany. This was the fourth part of this investigation of the morbidity variation due to Schistosoma mansoni infection in six african countries, a project sponsored by the WHO within its TDR programme. This comparison was based on the standardized description of morbidity as visualized by echography, following the "Cairo-1990" and the "Hannover-Managil-1989" classifications, and on coprology. One of the main objectives of this study was to demonstrate a morbidity variation at the scale of the African region (due to different S. mansoni strains or to a variable genetic background within the studied human populations), while participating to an international standardization effort for field echography. The project was conducted since July 1991 by a constant medical staff from Bonn and Hannover german universities. Eight foci in four african countries (Senegal, Mali, Uganda and Madagascar) are still analyzed and we are presenting here the first results. The data of an independent ultrasonographic investigation, organized by the Blair Institute and the Danish Bilharziasis Laboratory in Zimbabwe, was kindly proposed for this comparison. This project will end with the study of two supplementary foci in Tanzania and Burundi.