Chronic Hepatosplenomegaly in African School Children: A Common but Neglected Morbidity Associated with Schistosomiasis and Malaria

Abstract

Chronic hepatosplenomegaly, which is known to have a complex aetiology, is common amongst children who reside in rural areas of sub-Saharan Africa. Two of the more common infectious agents of hepatosplenomegaly amongst these children are malarial infections and schistosomiasis. The historical view of hepatosplenomegaly associated with schistosomiasis is that it is caused by gross periportal fibrosis and resulting portal hypertension. The introduction of ultrasound examinations into epidemiology studies, used in tandem with clinical examination, showed a dissociation within endemic communities between presentation with hepatosplenomegaly and ultrasound periportal fibrosis, while immuno-epidemiological studies indicate that rather than the pro-fibrotic Th2 response that is associated with periportal fibrosis, childhood hepatosplenomegaly without ultrasound-detectable fibrosis is associated with a pro-inflammatory response. Correlative analysis has shown that the pro-inflammatory response is also associated with chronic exposure to malarial infections and there is evidence of exacerbation of hepatosplenomegaly when co-exposure to malaria and schistosomiasis occurs. The common presentation with childhood hepatosplenomegaly in rural communities means that it is an important example of a multi-factorial disease and its association with severe and subtle morbidities underlies the need for well-designed public health strategies for tackling common infectious diseases in tandem rather than in isolation.

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

“…5,32 The positive association between S. mansoni and P. falciparum infections has been found in many studies 5,33,34 and may be driven by immunologic factors. [35][36][37] Anemia.…”

“…High prevalence of hepatomegaly in S. mansoni-infected children is linked to morbidity and effective treatment reduces hepatomegaly. 18,34,45 Furthermore, the earlier in life that these treatments occur, as disease is acquired at a young age, the greater the extent of reversibility as chronic infection is interrupted. 22 The specificity and attributable contribution of schistosomiasis to hepatomegaly is not clear given the high prevalence of hepatomegaly in our uninfected population.…”

An extensive burden of giardiasis associated with intestinal schistosomiasis and anaemia in school children on the shoreline of Lake Albert, Uganda

“…Local aetiological factors include favourable freshwater snail habitats, poor local sanitation and hygiene, as well as, extensive levels of daily water contact by shoreline communities [4][5][6] . While an extensive burden of malaria is known [7][8][9][10] , the occurrence and extent of another waterborne, poverty-related disease, giardiasis, has yet to be investigated. In 2003, a national control programme against schistosomiasis and intestinal worms was launched at Pakwach (see Figure 1) 11 .…”

Schistosoma mansoni Infection Impairs Antimalaria Treatment and Immune Responses of Rhesus Macaques Infected with Mosquito-Borne Plasmodium coatneyi

“…A protective effect of S. haematobium on malaria was also seen in Senegal, where children with light schistosome infections had significantly lower P. falciparum parasitemia than children without schistosomiasis (2). In contrast, Kenyan children with S. mansoni infections who were also chronically exposed to malaria had worse hepatosplenomegaly than children with schistosomiasis or malaria exposure alone (29,30). Additionally, Senegalese children with S. mansoni infec-tions demonstrated more clinical malaria compared to children not infected with schistosomes (24).…”