Malaria Transmission around the Memve’ele Hydroelectric Dam in South Cameroon: A Combined Retrospective and Prospective Study, 2000–2016

Abstract

Dam constructions are considered a great concern for public health. The current study aimed to investigate malaria transmission in the Nyabessan village around the Memve’ele dam in South Cameroon. Adult mosquitoes were captured by human landing catches in Nyabessan before and during dam construction in 2000–2006 and 2014–2016 respectively, as well as in the Olama village, which was selected as a control. Malaria vectors were morphologically identified and analyzed for Plasmodium falciparum circumsporozoite protein detection and molecular identification of Anopheles (A.) gambiae species. Overall, ten malaria vector species were identified among 12,189 Anopheles specimens from Nyabessan (N = 6127) and Olama (N = 6062), including A. gambiae Giles (1902), A. coluzzii Coetzee (2013), A. moucheti Evans (1925), A. ovengensis Awono (2004), A. nili Theobald (1903), A. paludis Theobald (1900), A. zieanni, A. marshallii Theobald (1903), A. coustani Laveran (1900), and A. obscurus Grünberg (1905). In Nyabessan, A. moucheti and A. ovengensis were the main vector species before dam construction (16–50 bites/person/night-b/p/n, 0.26–0.71 infective bites/person/night-ib/p/n) that experienced a reduction of their role in disease transmission in 2016 (3–35 b/p/n, 0–0.5 ib/p/n) (p < 0.005). By contrast, the role of A. gambiae s.l. and A. paludis increased (11–38 b/p/n, 0.75–1.2 ib/p/n) (p < 0.01). In Olama, A. moucheti remained the main malaria vector species throughout the study period (p = 0.5). These findings highlight the need for a strong vector-borne disease surveillance and control system around the Memve’ele dam.

Entomological and Anthropological Factors Contributing to Persistent Malaria Transmission in Kenya, Ethiopia, and Cameroon

“…moucheti . These species were responsible for >90% of malaria transmission cases in the forest region; these findings are consistent with previous studies in the area [ 15 , 48 ]. Other species such as An.…”

“…paludis and An. ovengensis were also recorded infected and involved in malaria transmission as reported in earlier studies [ 15–17 , 48 ]. In Kenya, vectors collected included An.…”

Knowledge, Attitude, and Practices (KAP) of Human Populations towards Malaria Control in Four Ecoepidemiological Settings in Cameroon

“…Several factors could be responsible for the subperformance of current control interventions. ese include the rapid expansion of insecticide resistance, which is largely expanding in the country, changes in vector resting feeding and biting behaviour, and the poor usage of treated nets by the population [6,[11][12][13][14][15][16].…”

An update on the mosquito fauna and mosquito-borne diseases distribution in Cameroon

“…rufipes , and An. ziemanni [ 6 , 16 , 24 , 27 , 32 , 34 , 45 , 48 , 102 ]. Anopheles mosquitoes are also known to transmit diseases such as O’Nyong Nyong (family Flaviviridae ) and lymphatic filariasis [ 75 ], but studies conducted so far in Cameroon specifically have not incriminated anopheline in the transmission of these diseases.…”

“…Cameroon has a diverse mosquito fauna with over 300 mosquito species thus far recorded in the country. The bionomics and distribution of Anopheline species have been extensively studied in Cameroon, and in many parts of the country, malaria transmission dynamics are complex and stable because of multiple vector species occurring in the same locality [ 7 , 16 , 22 – 25 , 27 , 32 , 34 – 48 ]. The distribution and bionomics of almost all the remaining mosquito genera are still not well documented across Cameroon.…”