The duration of Plasmodium falciparum infections

Abstract

Plasmodium vivax and Plasmodium ovale are often considered the malaria parasites best adapted to long-term survival in the human host because of their latent exo-erythrocytic forms. The prevailing opinion until the middle of the last century was that the maximum duration of Plasmodium falciparum infections was less than two years. Case reports and series investigating blood donors following accidental malaria infection of blood transfusion recipients and other sporadic malaria cases in non-endemic countries have shown clearly that asymptomatic P. falciparum infections may persist for up to a decade or longer (maximum confirmed 13 years). Current policies in malaria-free countries of excluding blood donors who have lived in malarious areas are justified. Vigilance for longer than three years after declaring elimination in an area may be needed.

Evidence-based vector control? Improving the quality of vector control trials

“…This study is unlikely to give a true picture of the efficacy of the repellent since compliance with the repellent would probably remain high during this short time period but decline over a longer time period. It is also worth noting that Plasmodium falciparum infections last on average 1 year [81,82], although they can persist for up to a decade or longer [83], and it takes several years for this indicator to re-equilibrate fully following a reduction of transmission [84,85].…”

Treatment of Chronic Asymptomatic Plasmodium falciparum Infection Does Not Increase the Risk of Clinical Malaria Upon Reinfection

“…Importantly, a large proportion of people in endemic areas are infected with P. falciparum without symptoms [3,4]. This clinically silent parasite reservoir, which persists for months to years [5] and contributes to ongoing malaria transmission [4,[6][7][8][9], poses a challenge for elimination efforts. The strategies of antimalarial mass drug administration (MDA) to at risk populations or mass screening and treatment (MSAT) of asymptomatically infected individuals are being considered in certain settings [10][11][12], particularly in areas of seasonal transmission where MDA during the dry season could reduce the number of gametocyte carriers and decrease transmission to the mosquito vector as the rainy season ensues [11,13,14].…”

Control of malaria outbreak due to Plasmodium vivax in Aswan Governorate, Egypt

“…Neither the duration of the infection nor the time of previous malaria treatment, if any, could be verified. Detection of asymptomatic carriers of P. falciparum parasites has been previously reported (9). Malaria infections have been detected in subjects after 8-9 years of leaving endemic areas (10,11).…”

“…These were coupled with implementation of vector control measures aimed at effectively reducing aquatic stages and adult vector populations and hence malaria transmission. The implemented vector control measures avoided the repeated use of the same class of insecticides or insecticides with similar modes of action which could accidental diagnosis of the infection has been as long as 13 years (9). Such a finding highlights the need for improved high throughput and low-cost methods to detect these individuals, probably harbouring low parasite densities.…”