Restaging Pulmonary Schistosomiasis.

Schistosomiasis is traditionally classified into an acute and a chronic phase, although a precise temporal distinction between the two phases has not been established. Lung involvement can be observed in both phases. We previously reported seven cases of pulmonary lesions due to chronic schistosomiasis in African immigrants. All cases were documented with CT scans and demonstrated complete resolution after treatment with praziquantel. Moreover, another case showed spontaneous disappearance of the nodule before treatment with praziquantel. These findings are similar to those observed in the acute phase of schistosomiasis, with well-defined or ground glass nodules that resolve spontaneously. According to these findings, we postulate the presence of an "intermediate" phase of schistosomiasis involving the lungs that can be defined as an "early chronic phase," and presents analogies to the acute phase. We also hypothesize that in the "early chronic phase," the female worms transit through the lungs where they may lay eggs. These passages not only cause transient, but also radiologically visible alterations. The pathophysiology of lung lesions in the late chronic phase is probably different: the adult worms settled in the mesenteric plexuses produce eggs for years. The eggs repeatedly migrate to the perialveolar capillary beds via portal-caval shunting. Thus, in this case it is the eggs and not the adult worms that reach the lungs in a scattered way. Based on our findings, we suggest the alternative hypothesis that the pulmonary involvement is a phase of the natural evolution of the infection, both from Schistosoma mansoni and Schistosoma haematobium.

[Ultrasonoic diagnosis of morbidity related to schistosomiasis due to Schistosoma mansoni and Schistosoma haematobium: epidemiological and individual value]. / Diagnostic échographique de la morbidité liée à la schistosomose à Schistosoma mansoni et à Schistosoma haematobium: intérêt épidémiologique, intérêt individuel.

By allowing study of large population samples, ultrasonography has revolutionized assessment of schistosomiasis-related morbidity. Previous clinical or parasitological parameters provided poor documentation of the public health impact of schistosomiasis. Thanks to a WHO-coordinated drive to standardize examination protocols and severity scores, comparison of data from different regions is now much easier. The latest "Niamey" methodology has eliminated the major shortcomings of earlier methods. Detection of periportal fibrosis is the cardinal diagnostic feature for Schistosoma mansoni. Ultrasonographic evidence has been validated by correlation with hepatic biopsy findings from hospitalized patients with severe disease. The specificity of ultrasonography is poor in low- or moderate-grade disease for which different methodologies give discordant results. Ultrasonography is highly sensitive for assessment of morbidity related to Schistosoma haematobium infection, which is associated with typical bladder lesions. Lesions involving the upper urinary tract are also well visualized but do not constitute a specific finding. The best applications for which ultrasonographic investigation of schistomsomiasis is now considered as mandatory are community-based studies and post-therapeutic follow-up of populations. In contrast ultrasonography is not well suited to individual diagnosis. In endemic areas, ultrasonography may be used for individual diagnosis if more effective methods are unavailable. However the poor specificity of some images is a major limitation for use in zones of low transmission.

Day-to-day variation of egg output and schistosome circulating antigens in urine of Schistosoma haematobium-infected school children from Gabon and follow-up after chemotherapy.

A group of 31 school children from Gabon infected with Schistosoma haematobium was examined before praziquantel therapy and followed on days 3, 9, 14, 21, 24, 28, 31 and 35 after therapy. The day-to-day variation of schistosome circulating antigens, urinary egg output, and the reagent strip index (RSI, a pathologic marker) was studied in six consecutive pretreatment urine samples collected under standardized conditions. The geometric mean pretreatment for egg output ranged between 97 and 223 eggs per 10 ml of urine; for urine circulating anodic antigen (CAA) levels this was 44-154 pg/ml and for circulating cathodic antigen (CCA) levels this was 180-601 pg/ml. On the day of treatment, 97% of the children had viable eggs in their urine, 87% had a positive RSI; positive CAA levels were detected in 61% of the children and positive CCA levels in 77%. A significant correlation was consistently found between RSI and egg counts. Five weeks after chemotherapy egg output, levels of CAA and CCA and the severity of pathologic findings in the lower renal tract, as indicated by the RSI, had decreased significantly in all cases. Our results indicate that egg output in urine is an accurate method for diagnosis of S. haematobium, and additionally show less day-to-day variation than detection by ELISA of schistosome circulating antigens in urine.