Larval salinity tolerance of two members of the <i>Anopheles funestus</i> group

Koekemoer, Lizette L.; Waniwa, Kelebogile; Brooke, Basil D.; Nkosi, G.; Mabuza, Aaron; Coetzee, Maureen

doi:10.1111/mve.12027

Cited by 8 publications

(6 citation statements)

References 11 publications

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“…Despite a relatively high salinity of 110 mg/l in Possotômè water, more than 70% of adults were able to emerge. This correlates with the observation of Koekemoer et al , (2014) 31 , where they reported that salinity does not affect the emergence of An. funestus adults.…”

Section: Discussionsupporting

confidence: 92%

Water source most suitable for rearing a sensitive malaria vector, Anopheles funestus in the laboratory

Tchigossou¹,

Akoton²,

Yessoufou³

et al. 2018

Wellcome Open Res

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The insecticide susceptibility status of one Background:Anopheles funestus, of the main malaria vectors in the Afrotropical regions, remains under-studied due to the difficulty of working with this mosquito species. Collecting their larvae in natural breeding sites, rearing and maintaining them in normal laboratory conditions have been a difficult task. Forced-egg laying technique has been a very good tool to generate eggs from adult mosquitoes collected from the wild but rearing these eggs to obtain satisfying portion as adults has always been the problem. In this study, we optimized the development of mosquito species larvae under standard laboratory conditions for desired production of adult mosquitoes that can be useful for insecticide susceptibility tests.A forced-egg laying technique was used to obtain eggs from gravid Methods: female collected from Kpome locality in Benin. Eggs were Anopheles funestus reared in three different water samples (water from the borehole, and two mineral water namely FIFA and Possotômè) and larvae were fed with TetraMin baby fish food. The physico-chemical parameters of the waters were investigated prior to use for egg incubation (introduction of eggs' batches into water).In contrast to mineral water that had no contamination, the borehole Results: water source was contaminated with lead (2.5mg/L) and nitrate (118.8mg/L). Egg hatching rates ranged as 91.9 ± 4.4%, 89.1 ± 2.5% and 87.9 ± 2.6% in FIFA, Possotômè and borehole water respectively. High emergence of larvae to adult mosquitoes was recorded as in FIFA (74.3%) and Possotômè (79.5%) water. No adult mosquito was obtained from larvae reared in borehole water.This study gave insight on the water sources that could be good Conclusions: for rearing to mass produce in the laboratory. More analysis with An. funestus other local mineral water sources in our environments could be considered in the future, hopefully giving better outputs.

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Section: Discussionsupporting

confidence: 92%

Water source most suitable for rearing a sensitive malaria vector, Anopheles funestus in the laboratory

Tchigossou¹,

Akoton²,

Yessoufou³

et al. 2018

Wellcome Open Res

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“…parensis have been observed to share aquatic habitats with An. funestus [ 31 ], though there can be differences in their level of tolerance to salinity [ 55 ]. Consequently, larval source management (LSM) targeted An.…”

Section: Introductionmentioning

confidence: 99%

Using ecological observations to improve malaria control in areas where Anopheles funestus is the dominant vector

Kahamba

Finda

Ngowo

et al. 2022

Malar J

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The most important malaria vectors in sub-Saharan Africa are Anopheles gambiae, Anopheles arabiensis, Anopheles funestus, and Anopheles coluzzii. Of these, An. funestus presently dominates in many settings in east and southern Africa. While research on this vector species has been impeded by difficulties in creating laboratory colonies, available evidence suggests it has certain ecological vulnerabilities that could be strategically exploited to greatly reduce malaria transmission in areas where it dominates. This paper examines the major life-history traits of An. funestus, its aquatic and adult ecologies, and its responsiveness to key interventions. It then outlines a plausible strategy for reducing malaria transmission by the vector and sustaining the gains over the medium to long term. To illustrate the propositions, the article uses data from south-eastern Tanzania where An. funestus mediates over 85% of malaria transmission events and is highly resistant to key public health insecticides, notably pyrethroids. Both male and female An. funestus rest indoors and the females frequently feed on humans indoors, although moderate to high degrees of zoophagy can occur in areas with large livestock populations. There are also a few reports of outdoor-biting by the species, highlighting a broader range of behavioural phenotypes that can be considered when designing new interventions to improve vector control. In comparison to other African malaria vectors, An. funestus distinctively prefers permanent and semi-permanent aquatic habitats, including river streams, ponds, swamps, and spring-fed pools. The species is therefore well-adapted to sustain its populations even during dry months and can support year-round malaria transmission. These ecological features suggest that highly effective control of An. funestus could be achieved primarily through strategic combinations of species-targeted larval source management and high quality insecticide-based methods targeting adult mosquitoes in shelters. If done consistently, such an integrated strategy has the potential to drastically reduce local populations of An. funestus and significantly reduce malaria transmission in areas where this vector species dominates. To sustain the gains, the programmes should be complemented with gradual environmental improvements such as house modification to maintain biting exposure at a bare minimum, as well as continuous engagements of the resident communities and other stakeholders.

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“…funestus group is broadly distributed across Africa, with its major species, An. funestus , widely distributed over subtropical and tropical Africa where it breeds in permanent large water bodies with emergent vegetation [ 7 , 11 ]. Anopheles funestus is highly anthropophilic (human biting) and exhibits endophilic (indoors) feeding and resting behaviours [ 7 , 12 ].…”

Section: Introductionmentioning

confidence: 99%

The effect of cattle-administered ivermectin and fipronil on the mortality and fecundity of Anopheles arabiensis Patton

2021

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Background Malaria control primarily depends on two vector control strategies: indoor residual spraying (IRS) and long-lasting insecticide-treated nets (LLINs). Both IRS and LLIN target indoor-biting mosquitoes. However, some of the most important malaria vectors have developed resistance against the chemical compounds used in IRS and LLINs. Insecticide-induced behavioural changes in vectors, such as increased outdoor feeding on cattle and other animals, also limit the effectiveness of these strategies. Novel vector control strategies must therefore be found to complement IRS and LLINs. A promising tool is the use of cattle-applied endectocides. Endectocides are broad-spectrum systemic drugs that are effective against a range of internal nematodes parasites and blood-feeding arthropods. The aim of this study was to investigate the effect of two endectocide drugs, injectable ivermectin and topical fipronil, on the survival and fecundity of zoophilic Anopheles arabiensis. Methods Laboratory-reared mosquitoes were allowed to feed on cattle treated with either injectable ivermectin (0.2 mg/kg), topical fipronil (1.0 mg/kg) or saline (control) on days 0, 1, 4, 7, 13, 21 and 25 post-treatment, and mortality and egg production were recorded daily. Results Compared to controls, the mortality of An. arabiensis increased by 3.52- and 2.43-fold with injectable ivermectin and topical fipronil, respectively. The overall fecundity of mosquitoes that fed on both ivermectin- and fipronil-treated cattle was significantly reduced by up to 90 and 60%, respectively, compared to the control group. The effects of both drugs attenuated over a period of 3 weeks. Injectable ivermectin was more effective than topical fipronil and increased mosquito mortality by a risk factor of 1.51 higher than fipronil. Similarly, both drugs significantly reduced the fecundity of An. arabiensis. Conclusions This study demonstrates that injectable ivermectin and topical fipronil are able to suppress An. arabiensis density and could help to reduce outdoor malaria transmission. Data from the present study as well as from other similar studies suggest that current-generation endectocides have a limited duration of action and are expensive. However, new-generation, sustained-release formulations of ivermectin have a multi-week, high mortality impact on vector populations, thus holding promise of an effective reduction of outdoor malaria transmission. Graphical abstract

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Larval salinity tolerance of two members of the Anopheles funestus group

Cited by 8 publications

References 11 publications

Water source most suitable for rearing a sensitive malaria vector, Anopheles funestus in the laboratory

Water source most suitable for rearing a sensitive malaria vector, Anopheles funestus in the laboratory

Using ecological observations to improve malaria control in areas where Anopheles funestus is the dominant vector

The effect of cattle-administered ivermectin and fipronil on the mortality and fecundity of Anopheles arabiensis Patton

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