Comparison of asymptomatic Plasmodium spp. infection in two malaria-endemic Colombian locations

Abstract

Measurement of the prevalence of asymptomatic Plasmodium spp. infection is suggested as part of the epidemiologic evaluation of malaria in low-transmission areas such as Colombia.

Monitoring, characterization and control of chronic, symptomatic malaria infections in rural Zambia through monthly household visits by paid community health workers

“…The far higher sensitivity with which these active household surveys by the CHWs detect cases of malaria infection is also reflected in the observation that this surveillance arm captured twice as high an incidence rate as the passive surveillance activities of the HFs and CHWs combined. The strong association of many symptoms, especially fever, headache and vomiting with malaria infection, particularly among individuals tested during active household visits by the CHWs, confirms previous reports that illustrate just how inaccurate the term asymptomatic is in relation to widespread chronic malaria infections [79-81] that clearly cause very large proportions of the overall burden of clinical illness in the community (Table 1, Figure 7). Clearly a large proportion of the population are infected with malaria, and suffering from a range of mild symptoms of clinical illness as a consequence, but do not feel ill enough to report to a HF or even to a nearby CHW to seek care.…”

Plasmodium malariae in the Colombian Amazon region: you don’t diagnose what you don’t suspect

“…This study thus confirms the need for using more sensitive diagnostic techniques to enable studying epidemiological factors affecting malarial endemicity [62]. Although microscopy may continue being the gold standard for routine diagnosis and the elimination of malaria, the high incidence of asymptomatic and sub-microscopic infections highlights the urgent need for rethinking the implementation of specific strategies for monitoring and eliminating malaria from urban/peri-urban and hypo-endemic areas, the proposed target in the Colombian Public Health Plan 2012–2021 [56].…”

“…Such limitations were highlighted due to comparison with a diagnostic test having greater sensitivity (PCR), something that has previously been shown in populations of asymptomatic individuals in Colombia [62]. This study thus confirms the need for using more sensitive diagnostic techniques to enable studying epidemiological factors affecting malarial endemicity [62].…”

Malaria in Brazil, Colombia, Peru and Venezuela: current challenges in malaria control and elimination

“…In Asia and Latin America, both low transmission malaria settings, there is now strong evidence showing that a significant proportion of positive cases detected by molecular methods is missed by microscopic examination of blood smear samples, as well as by RDTs [109–113] (Table 3). High PCR sensitivity over microscopy and RDT diagnosis was confirmed by studies from Canada that assessed the prevalence of malaria in asymptomatic refugees [114, 115].…”