Clinical Manifestations of Malaria

Introduction to Malaria Symptoms

The American College of Physicians recommends that malaria be suspected in patients presenting with fever and non-specific symptoms such as headaches, chills, sweats, myalgias, nausea, vomiting, diarrhea, and cough, with a likelihood ratio of 5.1 for diagnosis 1, 2
The Centers for Disease Control and Prevention notes that headaches, back pain, chills, and sweats are frequently associated with malaria 1, 2
The World Health Organization states that myalgias, nausea, vomiting, diarrhea, and cough complete the clinical picture of malaria 1, 2

The European Society of Clinical Microbiology and Infectious Diseases recommends that splenomegaly be considered a predictive sign with a likelihood ratio of 6.6 for diagnosis 3
The British Medical Journal notes that visible jaundice may be present and increases the likelihood of diagnosis 3, 5
The Infectious Diseases Society of America states that thrombocytopenia (<150,000/mL) occurs in 70-79% of patients and represents the most frequent biological anomaly 3, 4

The World Health Organization warns that untreated P. falciparum malaria can progress to coma, renal failure, pulmonary edema, and death 1, 2
The Centers for Disease Control and Prevention notes that neurological, renal, pulmonary, and hematological complications can occur rapidly 5

The American Society of Tropical Medicine and Hygiene recommends that travelers to endemic areas be aware that symptoms typically begin 10 days to 4 weeks after transmission, but can occur as early as 8 days or as late as 1 year after exposure 5
The Pediatric Infectious Diseases Society states that children often present with fever, cough, headaches, malaise, vomiting, and diarrhea 5
The European Society of Clinical Microbiology and Infectious Diseases notes that asymptomatic parasitemia can occur in individuals who have lived in endemic areas for a long time 1, 2

The British Medical Journal warns that a single negative blood smear should not be used to rule out malaria - three negative smears at 12-hour intervals are necessary to exclude the diagnosis 5, 4
The Infectious Diseases Society of America states that delayed diagnosis of P. falciparum malaria is associated with increased mortality 3, 4
The Centers for Disease Control and Prevention recommends that any febrile patient who has traveled to an endemic area should undergo immediate screening 1, 3, 2