Regression of hepatosplenomegaly in Kenyan school-aged children after praziquantel treatment and three years of greatly reduced exposure to Schistosoma mansoni

Abstract

Evaluating regression of morbidity associated with parasitic infections is an important component of community-based control programmes. We performed an intervention against Schistosoma mansoni infection, focusing on hepatosplenomegaly in the absence of periportal fibrosis, in a cohort of 67 Kenyan children aged 7-18 years from Makueni District, selected on the basis of hepatosplenomegaly detected by ultrasonography. Clinical and ultrasound examinations were conducted annually for three years after treatment, and the source of infection (a river) was regularly treated with molluscicide, thereby severely reducing exposure to schistosomiasis. Malaria transmission was uninterrupted. The prevalence of hard spleens, and the magnitude of clinically assessed splenomegaly along the mid-axillary and mid-clavicular lines decreased monotonically over time, independently of age, whereas clinically measured hepatomegaly along the mid-sternal line and the prevalence of firm livers decreased in an age-specific manner, being more pronounced amongst children aged 14 years or older at enrolment. Ultrasound data were less informative, and did not concur with clinical observations. These results demonstrate that praziquantel treatment reduces hepatosplenomegaly in the absence of exposure to S. mansoni, even with continuing exposure to malaria. The lack of complete resolution of hepatosplenomegaly in most children suggests, among other things, a residual organomegaly attributable to malaria.

Morbidity due to Schistosoma mansoni: an epidemiological assessment of distended abdomen syndrome in Ugandan school children with observations before and 1-year after anthelminthic chemotherapy

“…The ACR metric may provide a more direct quantification of pathognomonic signs (as evidenced by the children shown in Figure 2) and enables convenient comparison between children. In accordance with recent findings (Vennervald et al, 2005), a high proportion (67.8%) of the children in our sample had firm and >1 cm enlarged livers and spleens, with several showing surprisingly advanced liver fibrosis on ultrasound. Although the distribution of the ACRs across the sample appeared normal (see Figure 3), further analysis of ACR scores revealed geographic overdispersion within Bugiri, Hoima and Mayuge districts and pinpointed several schools where morbidity appeared much elevated (Figure 4).…”

“…A negative correlation between the change in ACR (ACR 1 − ACR 0 ) and the mean of the two ACR values (0.5[ACR 0 + ACR 1 ]) showed a tendency of higher mean ACR scores by school to show a larger decrease than those with lower mean ACR scores. The ameliorative effect of treatment on reduction of organomegaly is well known (Boisier et al, 1998;Vennervald et al, 2005). However, regression towards the mean can also be a general statistical phenomenon of a reduced sample size.…”

Impact on a national helminth control programme on infection and morbidity in Ugandan schoolchildren

“…7,36 However, 39.4% of children had liver pattern B, indicative of early signs of morbidity. Following treatment, the prevalence of liver pattern B decreased significantly.…”

“…Clinical trials have demonstrated that praziquantel is a safe and efficacious treatment against both species, and that repeated chemotherapy decreases infection and related morbidity. [1][2][3][4][5][6][7] One of the main control methods is treating schoolchildren with praziquantel together with albendazole as part of school health programmes. As this method uses the existing school infrastructure and provides easy accessibility to children, it is a cost-effective public health strategy, 8 and many pilot programmes have demonstrated its feasibility, affordability and effectiveness.…”

Schistosoma mansoni Morbidity among School-Aged Children: A SCORE Project in Kenya

“…16 Currently, the WHO strategy for schistosomiasis control relies on mass-drug administration (MDA) of praziquantel, 17 which is effective in reducing disease-associated morbidity. [18][19][20][21][22] The impact of MDA is measured by a change in infection prevalence and intensity. Guidelines exist for schistosomiasis MDA thresholds, frequency, and target populations (school-based versus community-wide), but there are few objective data supporting them.…”