Health Consequences of SchistosomiasisLight infections with schistosomiasis can be asymptomatic, and many people may live their lives without knowing they have ever been infected. However, globally, up to 120 million of the estimated 200 million infected people are believed to be symptomatic, and as many as 20 million may well be suffering severe consequences of their infection. The annual deaths associated with schistosomiasis are estimated at 20,000. The first obvious symptom of Schistosoma haematobium infection is blood in the urine (haematuria). Early signs of morbidity common to S.haematobium and S.mansoni, and which manifest in school age children are anaemia, impaired growth, impaired development, poor cognition, and substandard school performance. Since S.mansoni eggs are voided through the faeces, intestinal symptoms such as diarrhoea with or without blood are found in heavy infections. However none of these signs and symptoms are due solely to schistosomiasis, and so a diagnosis on clinical presentation is difficult. Due to the non-specific signs and symptoms, many S.mansoni affected persons may never realise they have the infection, and thus do not seek treatment. Equally, many health decision makers do not perceive schistosomiasis as a serious health problem, which means the disease can progress untreated to the development of late, irreversible sequelae. The late and life threatening consequences of schistosomiasis
include bladder cancer or serious kidney malfunction, caused by S.haematobium,
and severe complications of the liver and spleen in the case of intestinal
schistosomiasis. Mortality is rarely acknowledged to be caused by
schistosomiasis, because there is no recognition of the link between
schistosomiasis infection in early life and later development of bladder cancer
or renal failure associated with urinary schistosomiasis and liver fibrosis and
portal hypertension associated with intestinal schistosomiasis. |