The rest of this chapter describes the clinical manifestations of malaria to aid in early diagnosis and understanding of disease processes. Patients present with a variety of symptoms depending on the stage of infection and the infecting species. Fever is virtually always present, and fever plus any other symptom might be malaria if exposure occurred. Common complaints include mild to moderate malaise, fatigue, muscle aches, back pain, headache, dizziness, loss of appetite, nausea, vomiting, abdominal pain, and diarrhea. Dry cough and shortness of breath have been reported in some patients.
Gastrointestinal complaints can be considerable, suggesting a diagnosis of gastroenteritis.
Young children and semi-immune individuals may complain of fever and headache as their only symptoms. Physical examination usually demonstrates an increased temperature, tachycardia, and warm flushed skin. The spleen is often palpable in initial infection, but this is more likely in subsequent attacks. It is usually soft and may be tender. Orthostatic hypotension often occurs during initial infections.