Malaria epidemiology and anti-malarial drug efficacy in Guinea: a review of clinical and molecular studies

Abstract

Malaria is one of the leading causes of mortality and morbidity in Guinea. The entire country is considered at risk of the disease. Transmission occurs all year round with peaks occurring from July through October with Plasmodium falciparum as the primary parasite species. Chloroquine (CQ) was the first-line drug against uncomplicated P. falciparum in Guinea until 2005, prior to the adoption of artemisinin-based combination therapy (ACT). In this review, data on therapeutic efficacy of CQ and artemisinin-based combinations reported in published literature is summarized. Against CQ, a failure rate of 27% (12/44) was reported in a study in 1992; a median failure rate of 15.6% [range: 7.7–28.3; 8 studies] was observed during 1996–2001, and 81% (17/21) of the patients failed to clear parasitaemia in a study conducted in 2007. For artemisinin-based combinations, three published studies were identified (1495 patients; 2004–2016); all three studies demonstrated day 28 polymerase chain reaction corrected efficacy > 95%. One study characterized kelch-13 mutations (389 tested; samples collected in 2016) with no evidence of mutations currently known to be associated with artemisinin resistance. The impact of the ongoing COVID-19 pandemic and widespread usage of counterfeit medicines are immediate challenges to malaria control activities in Guinea.

Caregivers’ use of insecticide-treated nets is associated with the use of ITNs by children under the age of five in Ghana

“…Nearly one million people die each year from malaria [2]. The Plasmodium parasites cause malaria, which is transmitted when one is bitten by anopheles mosquitoes [3,4]. Globally, malaria cases increased from 227 million in 2019 to 241 million in 2020, with most of this increase occurring in the African region [5].…”

Perceptions of COVID-19 among communities of Conakry (Guinea): a qualitative study exploring the context of the ANRS COV33 Coverage-Africa therapeutic trial

“…Guinea also had to deal with a resurgence of Ebola in early 2021, as well as epidemics caused by Lassa fever, measles, meningitis and yellow fever. 27 Malaria, which is ubiquitous and the leading cause of mortality in Guinea, causes more deaths annually (over 8000 29 ) than COVID-19 has caused so far nationwide since the beginning of the epidemic in March 2020 (388 deaths related to COVID-19 as of 7 December 2021 1 ). While the prevalence of COVID-19 is low in Guinea (30 798 confirmed cases 1 for a population of nearly 13 million people 24 =0.2%), seroprevalence studies indicate that at least 25% of West African population have developed anti-SARS-CoV-2 antibodies, 30 which suggests that additional undetected cases would have been asymptomatic or paucisymptomatic, contributing to the ‘invisibility’ of the disease or to the perception that COVID-19 is a ‘bad cold’.…”

High prevalence of asymptomatic malaria in Forest Guinea: Results from a rapid community survey

“…(11) Since these surveys were conducted, additional control efforts have been implemented in hyper- and holo-endemic settings, notably roll-out of seasonal chemoprophylaxis to high-risk groups. The main parasite present in Guinea is Plasmodium falciparum (8).…”

“…The extent to which these asymptomatic infections exist in a population may help to determine the effectiveness of existing control efforts. Guinea is highly endemic for malaria, with Forest Guinea being a hyper-endemic area, experiencing year-round transmission (7,8), while the holo-endemic coastal and middle regions of the country see more seasonal transmission (8)(9)(10). Overall malaria incidence ranged from 87-101 per 1000 per year in between 2006-2010 (9).…”

“…In 2021, malaria prevalence among symptomatic and asymptomatic children of 6-59 months ranged from 1.5% (Conakry capital region) to 55.0% (N’Zérékoré, Forest Guinea) ⍰⍰⍰(12)n 2011, parasite prevalence in all age groups ranged from 3% (Conakry capital region) to 66% (Forest Guinea). (11) The main parasite present in Guinea is Plasmodium falciparum (8). Given the lack of understanding of the prevalence of and subsequentially the contribution to transmission, we sought to estimate the prevalence of asymptomatic malaria in older children and adults in Middle Guinea and Forest Guinea.…”