Table 1 A wide range of diagnostic criteria is used for defining malaria patients as asymptomatic
From: The complexities of malaria disease manifestations with a focus on asymptomatic malaria
Country and Year | Criteria used for identifying asymptomatic malaria cases | Study subjects, sample size | Follow-up protocol and duration | Ref. |
|---|---|---|---|---|
Africa | ||||
Gabon, 2003 | No clinical symptoms of malaria with a P. falciparum positive blood smear, asymptomatic for at least 5 days during follow-up. | Children 6 months to 10 years, N = 60 | Examined once daily for 7 days thereafter, once every 2 days | [37] |
Tanzania, 2006 | Presence of P. falciparum on blood smear, axillary temperature of < 37.5°C, and no other symptoms or signs of malaria | Children 4-59 months, N = 127 | No follow-up. | [33] |
South America | ||||
Brazilian Amazon, 2002 | Individuals positive by microscopy, and/or positive by PCR; and individuals negative by microscopy that subsequently became positive by PCR. | All age groups, N = 172 | Follow-up to day 10 and 60. | [21] |
Colombia, 2008 | Presence of microscopic asexual parasite stages of P. falciparum, P. vivax or P. malariae or of mixed infections in blood, which persisted for at least two weeks without causing any symptoms, or as the detection of parasite DNA by PCR on day 0 in people who remained asymptomatic during the follow-up period. | Individuals 2-78 years, N = 21 | Follow-up on days 14 and 28. | [19] |
Asia | ||||
Papua, 2003 | No fever history or treatment for malaria within the past week, no clinical evidence of malaria or other infection, no diarrhea, and no current pregnancy but both P. falciparum and P. vivax positive individuals | Adults > 16 years, N = 105 | Supervised overnight at local health center. A third axillary temperature was recorded the following morning. | [38] |
Indonesia, 2010 | Presence of asexual P. falciparum or P. vivax parasitemia in the absence of fever (temperature ≤ 37.9°C) and of clinical signs or symptoms suggestive for malaria or another infectious disease. | Children 5-15 years, N = 381 | No follow-up. | [27] |