The Epidemiology of Plasmodium falciparum Malaria in the Bijagos Islands of Guinea-Bissau

Abstract

Distribution of long-lasting insecticide-treated nets (LLINs), passive detection and treatment with artemisinin-based combination therapy (ACT), and intermittent preventive treatment in pregnancy (IPTp) are the mainstay malaria control measures of Guinea-Bissau’s national control programme. This study aimed to estimate the prevalence of Plasmodium falciparum on Bubaque, the most populous island of the country’s remote Bijagos archipelago. A cross-sectional survey was performed at the start of the rainy season in August 2017. Participants were recruited using systematic random sampling in a two-stage stratified cluster design. Malaria parasitemia was detected using rapid diagnostic tests (RDTs) and quantitative PCR (qPCR). Data on housing, education, larval source management, socioeconomic status, anemia, and malaria preventive measures were collected. Multivariable logistic regression models were constructed to identify associations with P. falciparum infection. Four hundred four persons (aged 6 months–79 years, median 17 years) were enrolled in the study. The prevalence of P. falciparum parasitemia was 5.8% by RDT (95% CI: 3.55–9.33) and 16.9% by qPCR (95% CI: 13.09–21.71). The prevalence of anemia was 74.3% (95% CI: 69.04–78.85) as defined by the WHO criteria. All sampled houses were found to have open eaves; 99.5% of the surveyed population reported sleeping under a bednet (95% CI: 97.8–99.9). Although reported LLIN use is high, there remains an appreciable prevalence of malaria, suggesting that transmission is ongoing and further tools are required to reduce the burden of the disease.

Population dynamics and drug resistance mutations in Plasmodium falciparum on the Bijagós Archipelago, Guinea-Bissau

“…This is vital for researchers to be able to understand the impact of malaria interventions within the region. Eighteen of the islands within the archipelago are inhabited year-round, with a total population of around 25,000 people 5 . The majority of the population live in forest villages and are largely hunter gatherers with some subsistence farming and fishing 4 .…”

“…A malaria prevalence survey was conducted on the most populated island within the archipelago in August 2017, during the start of the malaria transmission season. This was a cross-sectional survey of the population, which identified the prevalence of P. falciparum infection to be 16.9% by qPCR 5 . Persistent circulation of subclinical parasitaemia makes reducing malaria transmission very difficult in this setting.…”

“…Persistent circulation of subclinical parasitaemia makes reducing malaria transmission very difficult in this setting. This is because asymptomatic malaria cases are a major driver of malaria transmission, and asymptomatic individuals do not generally seek treatment 5 .…”

The Effects of HIV Infection on the Immune Response to Malaria Among Pregnant Women in Kumba, Southwest Cameroon: Protocol for a Cross-sectional Study

“…In 2019, malaria alone affected over 229 million people worldwide, with the majority (95%) of the cases occurring in 29 countries in sub-Saharan Africa: Nigeria (27%), Democratic Republic of Congo (12%), Uganda (5%), Mozambique (4%), and Niger (3%) [ 2 ]. Infection with malaria in humans is caused by 6 species, with Plasmodium falciparum being the most virulent of them all [ 3 ]. In Cameroon, malaria is a significant public health issue, with the whole nation in danger of transmission [ 4 , 5 ].…”