Shrinking the Malaria Map

UCSF Global Health Group’s Malaria Elimination Initiative (MEI)

Malaria researchers challenge the established perspective on "asymptomatic" malaria

19 January 2016

Many malaria infections are “asymptomatic" and do not cause obvious symptoms or severe disease. The prevailing view in the infectious disease community is that asymptomatic malaria infections are harmless and sometimes beneficial to the individual by conferring partial immunity from malaria and reducing the risk of severe disease.

In a PLOS Medicine article out today, "Asymptomatic” Malaria: A Chronic and Debilitating Infection That Should Be Treated, MEI authors Ingrid Chen and Roly Gosling and their collaborators present four strands of evidence that asymptomatic malaria infections are detrimental and that treatment will clinically benefit the individual.

The four strands of evidence include the following:

  • Malaria control interventions lead to decreases in all-cause mortality and morbidity, particularly from invasive bacterial disease;
  • Both asymptomatic and symptomatic malaria infections can cause anemia, increasing the risk of mortality;
  • A molecular mechanism indicates a direct causal association between malaria infection, anemia, and potentially fatal bacteremia; and
  • Malaria infections of any density are harmful to cognitive performance, as shown in the impact of malaria interventions on school performance in children.

In light of the serious health and societal consequences of malaria infections at any density, the authors call for “comprehensively tackling the reservoir of chronic human malaria infection.” Targeting asymptomatic infections not only contributes to malaria control and elimination efforts, but also provides enormous benefits to public health. In light of these potential gains, the authors assert that despite significant operational challenges to detecting and treating chronic malaria infections, asymptomatic cases can and should be targeted and treated.