Species Composition and Role of Anopheles Mosquitoes in Malaria Transmission Along Badagry Axis of Lagos Lagoon, Lagos, Nigeria

Abstract

Three communities along Badagry axis of the Lagos lagoon were sampled for indoor resting Anopheles mosquitoes in order to determine their species composition, relative abundance, density and contribution to malaria transmission in the coastal ecosystem. A total of 1938 adult female Anopheles mosquitoes collected from 2005 to 2007 constituted three species viz Anopheles gambiae, An melas and An. nili. The Polymerase Chain Reaction (PCR)–-based tests indicated that more than three-fourth of the An. gambiae s.l (75.8%) population belongs to An. gambiae s.s the remaining were An. melas. Further analysis showed that all the An. gambiae s.s was the M form. ELISA-based analyses indicated that An. gambiae s.s and An. melas were the main vectors of malaria in this area with an overall P. falciparum sporozoite infection rate of 4.8% and 6.5% respectively. Both species also maintained relatively high EIR indicating their prominent roles in malaria transmission in the study area. All the An. nili tested were negative for P. falciparum sporozoite infection. This study provides baseline information for planning vector control programme relevant to reduction of malaria transmission in the coastal areas of Nigeria.

A Simple Key for Identifying the Sibling Species of the Malaria Vector Anopheles gambiae (Giles) Complex by Polytene Chromosome Cytogenetics

“…However, the sporozoite infection rates that were obtained were significantly higher than the ones previously reported, 6.70% and 6.30% in 2001 and 2002 respectively, at Igbo-Ora, Oyo State in South-Western Nigeria (Noutcha and Anumdu, 2009), as well as at Badagry Axis of Lagos Lagoon, Lagos State, Nigeria (Oyewole et al, 2010). However, Obembe and Awopetu (2014) has reported similarly high P. falciparum sporozoite rates in the study areas.…”

<span>Sporozoite Infection Rate and Identification of the Infective and Refractory Species of <i>Anopheles gambiae</i> (Giles) Complex</span>

“…For instance, the P. falciparum sporozoite infection rates for A. gambiae that were recorded at Igbo-Ora in 2001 and 2002, a rural community of Oyo State in south-west Nigeria, were 6.70% and 6.30% respectively (Noutcha and Anumdu, 2009). Along Badagry Axis of Lagos Lagoon, Lagos, Nigeria, P. falciparum sporozoite infection rates of 4.8% and 6.5% for A. gambiae s.s and A. melas respectively were reported (Oyewole et al, 2010). Oduola et al (2012) reported that P. falciparum sporozoite infection rates of A. gambiae s.s. in six rural communities of Oyo State, Southwestern Nigeria, varied between 1.9% and 3.1%.…”

Malaria, a Pending Problem in Sub-Saharan Africa

“…The An. gambiae complex is not the only vector in the field [6,8]. Targeting only this species by whatever method is nonsense.…”

“…Meanwhile, the distribution of the molecular M (Mopti) and S (Savannah) forms of An. gambiae s.s is still being determined for much of the West African regions [6,8]. The malaria problem in sub-Saharan Africa represents a peculiar case because the vectoral system is the most complex anywhere.…”

“…The vectors associated with stable malaria are those which are strongly antropophagic, often feeding on humans to the exclusion of other hosts. Anopheline vectors of malaria consists of various behavior associated with their biting activities and hence transmission dynamics [6].…”