A new malaria vector mosquito in South Africa

Abstract

South Africa aims to eliminate malaria within its borders by 2018. Despite well-coordinated provincial vector control programmes that are based on indoor residual insecticide spraying, low-level residual malaria transmission continues in the low-altitude border regions of the north-eastern sector of the country. In order to identify the underlying causes of residual transmission, an enhanced vector surveillance system has been implemented at selected sites in the Mpumalanga and KwaZulu-Natal (KZN) provinces. The collection periods for the data presented are March 2015 to April 2016 for Mpumalanga and January 2014 to December 2015 for KZN. The mosquito collection methods used included indoor and outdoor traps based on the use of traditional ceramic pots, modified plastic buckets and exit window traps (KZN only). All Anopheles funestus species group mosquitoes collected were identified to species and all females were screened for the presence of Plasmodium falciparum sporozoites. Two An. vaneedeni females, one from each surveillance site, tested positive for P. falciparum sporozoites. These are the first records of natural populations of An. vaneedeni being infective with P. falciparum. As both specimens were collected from outdoor-placed ceramic pots, these data show that An. vaneedeni likely contributes to residual malaria transmission in South Africa.

A comparative assessment of adult mosquito trapping methods to estimate spatial patterns of abundance and community composition in southern Africa

“…This approach is a better approximation to how the traps would be deployed for surveillance compared to targeting only sites with high numbers of mosquitoes. Despite this, the CDC trap collected 7.4 females per night while the net trap collected 8.6 females per night, similar to previous collection efforts in KNP that report aggregated data, with a median of 31 (range 17-116) females across three net traps and a median of 19 (range [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] in three CDC traps [15]. Based on this data, the consistent patterns of community composition and largely consistent patterns of abundance between traps suggest that comparisons between studies using these two methods are possible.…”

“…Chikungunya and dengue fever outbreaks are less common in South Africa [14], but we describe the distribution of their vector, Ae. aegypti [22], because additional known prime vectors in Africa were not found (Ae. africanus, Ae.…”

High levels of imported asymptomatic malaria but limited local transmission in KwaZulu-Natal, a South African malaria-endemic province nearing malaria elimination

“…Currently in KZN, larval source management is employed in an ad hoc uncoordinated manner. The KZN control programme should consider upscaling its use; guided by regularly updated breeding site maps and comprehensive data management, to control out-door resting vector populations associated with sustaining residual transmission in KZN [15,40]. As vector populations with reduced susceptibility to pyrethroids were detected in this study and have been confirmed in neighbouring Mozambique [41], it is imperative that resistance susceptibility testing becomes a routine programmatic activity, with the data generated used to inform insecticide selection.…”

Mosquito community composition and abundance at contrasting sites in northern South Africa, 2014–2017

“…Of the Anopheles funestus group, the species identified by PCR assays was An. vaneedeni, a secondary vector for malaria in the region (Burke et al 2017). There was a significant difference between locality and mosquito abundance for the seven widely distributed potential vectors of arboviruses with the Chi‐Square test P ‐value for all species being <0.001).…”

“…vaneedeni (a member of the An. funestus group) playing a secondary role (Burke et al 2017). Nevertheless, this information is of importance and value from a public health perspective in creating awareness among health department officials and tourism operators regarding the potential for malaria transmission.…”