The onset of illness is abrupt with shivering and a rapid rise in temperature accompanied by severe headache, backache and muscle and joint pains. Gastro-intestinal disturbances may be a presenting feature, but more commonly commence on about the third day with anorexia, nausea, vomiting and diarrhoea. The stools are watery and sometimes contain blood and mucus. Profuse diarrhoea may continue for several days and will lead to severe dehydration unless treated. The throat and conjunctivae may be inflamed and small transparent lesions resembling tapioca granules may be present on the soft palate.
Many patients bleed spontaneously and renal failure is common in fatal cases.
As the disease progresses, severe thrombocytopenia, neutrophilia and leueopenia develop accompanied by elevated levels of aspartate aminotransferase. Within a few days of onset of symptoms, patients show signs of alteration in mental state and extreme lethargy, and usually become critically ill. In fatal cases, death generally occurs at the beginning of the second week. Treatment of cases No antiviral drug, vasoactive agent or cytokine has been shown to alter the course of disease. Recent work suggests that hyperimmune serum may modify the severity of disease, but no trials in human disease have been possible.