A genotypically distinct, melanic variant of Anopheles arabiensi s in Sudan is associated with arid environments

Aboud, Mariam A.; Makhawi, Abdelrafie M.; Verardi, Andrea Antonio; Raba’a, Fathi El; Elnaiem, Dia-Eldin A.; Townson, Harold

doi:10.1186/1475-2875-13-492

Cited by 6 publications

(6 citation statements)

References 58 publications

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“…Of 21 Anopheles gambiae specimens collected in Central Kenya (Mwea), 11 were shown to be Spiroplasma insolitum GAMB positive based on PCR based screening. We identified a total of 6 haplotypes, four of these are identical to haplotypes reported previously ( Aboud et al ., 2014 ; Besansky et al ., 1997 ), while two were novel (M1 and M2, see Figure 6 ). In the 4 most common haplotypes, we found both Spiroplasma insolitum GAMB infected and uninfected individuals, suggesting that this symbiont is either an ancient infection or exhibits appreciable levels of horizontal transmission.…”

Section: Resultssupporting

confidence: 71%

Identification of Spiroplasma insolitum symbionts in Anopheles gambiae

et al. 2017

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Background: Insect symbionts have the potential to block the transmission of vector-borne diseases by their hosts. The advancement of a symbiont-based transmission blocking strategy for malaria requires the identification and study of Anopheles symbionts. Methods: High throughput 16S amplicon sequencing was used to profile the bacteria associated with Anopheles gambiae sensu lato and identify potential symbionts. The polymerase chain reaction (PCR) with specific primers were subsequently used to monitor symbiont prevalence in field populations, as well as symbiont transmission patterns. Results: We report the discovery of the bacterial symbiont, Spiroplasma, in Anopheles gambiae in Kenya. We determine that geographically dispersed Anopheles gambiae populations in Kenya are infected with Spiroplasma at low prevalence levels. Molecular phylogenetics indicates that this Anopheles gambiae associated Spiroplasma is a member of the insolitum clade. We demonstrate that this symbiont is stably maternally transmitted across at least two generations and does not significantly affect the fecundity or egg to adult survival of its host. Conclusions: In diverse insect species, Spiroplasma has been found to render their host resistant to infection by pathogens. The identification of a maternally transmitted strain of Spiroplasma in Anopheles gambiae may therefore open new lines of investigation for the development of symbiont-based strategies for blocking malaria transmission.

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Section: Resultssupporting

confidence: 71%

Identification of Spiroplasma insolitum symbionts in Anopheles gambiae

et al. 2017

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“…It is more likely that resistant gravid female choose the available polluted water as a last chance to lay its eggs when they have no choice during the hot dry season to find an alternative habitat which require more flying during an extreme harsh environmental condition. Aboud et al [ 14 ] reported that the haplotype diversity within melanic populations of An. arabiensis was higher than within normal populations and better adapted to hot and arid environments.…”

Section: Discussionmentioning

confidence: 99%

“…In the laboratory, larvae were identified morphologically using [ 12 ] and molecularly using species-specific identification according to [ 13 ]. Melanic and normal forms were classified according to [ 14 ].…”

Section: Methodsmentioning

confidence: 99%

Anopheles arabiensis in Sudan: a noticeable tolerance to urban polluted larval habitats associated with resistance to Temephos

Azrag

Mohammed

2018

Malar J

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BackgroundIt has been documented that unplanned urbanization leads to the exposure of members of the Anopheles vectors to a range of water pollution in urban settings. Many surveys from African and Asian countries reported the presence of Anopheles larvae in polluted urban habitats. The present study documents an obvious tolerance of the melanic and normal forms of Anopheles arabiensis to urban polluted larval habitats accompanied by resistance to Temephos larvicide.MethodsA cross-sectional survey was carried out to inspect apparently polluted An. arabiensis larval habitats during the hot dry season of 2015. Larval specimens were collected from only apparently polluted habitats after visual inspection from 5 localities in Khartoum State. After morphological and molecular identification of random samples of larvae the magnitude of water pollution was determined using nine abiotic factors. The susceptibility status of An. arabiensis larval forms from normal and polluted habitats to Temephos was tested using the WHO standard diagnostic concentration doses.ResultsMorphological and PCR analysis of anopheline larvae revealed the presence of An. arabiensis, a member of the Anopheles gambiae complex. Seven out of 9 physiochemical parameters showed higher concentrations in polluted larval habitats in comparison to control site. Anopheles arabiensis larvae were found in water bodies characterized by high mean of conductivity (1857.8 ± 443.3 uS/cm), turbidity (189.4 ± 69.1 NTU) and nitrate (19.7 ± 16.7 mg/l). The range of mortality rates of An. arabiensis larvae collected from polluted habitats in comparison to An. arabiensis larvae collected from non-polluted habitats was 6.7–64% (LD50 = 1.682) and 67.6–96% (LD50 = 0.806), respectively.ConclusionsThe present study reveals that minor populations of An. arabiensis larval forms are adapted to breed in polluted urban habitats, which further influenced susceptibility to Temephos, especially for the melanic larval forms. This could have further implications on the biology of the malaria vector and on the transmission and epidemiology of urban malaria in Sudan.

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“…Rather, weak dispersers are commonly studied at much smaller spatial scales (for example, <200 km radius) (Murphy et al, 2010;Myers et al, 2001). Despite some progress, there is much to learn about how aridity shapes the genetic divergence and evolution of aquatic insects in these naturally fragmented systems (Aboud et al, 2014;Chessman, Jones, Searle, Growns, & Pearson, 2010;Myers, Sperling, & Resh, 2001).…”

Section: Introductionmentioning

confidence: 99%

Evolutionary divergence in freshwater insects with contrasting dispersal capacity across a sea of desert

et al. 2017

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Summary Arid landscapes pose arguably one of the greatest challenges to dispersal of aquatic insects, and may drive speciation in taxa with low dispersal potential. We investigated genetic divergence in aquatic insects with high and low dispersal potential between two regions within the Australian arid zone. We used two dragonfly species to infer patterns for strong‐dispersing species, and mayfly species from two genera to represent weak‐dispersing species. Based on dispersal‐related traits of the taxa, we predicted that dragonflies would show little divergence between and within the two geographical regions, while mayflies would show evidence of genetic isolation, with divergence timing associated with aridification in Australia. Samples were collected from perennial pools in ephemeral stream networks in central and western Australia. The two study regions are separated by approximately 1,500 km of predominantly dune desert. Collected insects were sequenced for one mitochondrial and one nuclear marker. We investigated spatial distribution of haplotypes, estimated divergence dates for identified mayfly lineages, and performed phylogenetic reconstruction to investigate relationships with known congeners. Both dragonfly species showed evidence of recent or ongoing gene flow between the central and western Australian study regions. In contrast, mayflies showed evidence of ancient, but not recent, gene flow between regions, with species‐level CO1 divergence within regions. We found 11 previously unknown putative mayfly species, that if confirmed could double the known diversity within these genera in Australia. Timing of divergence events for mayflies coincided with the development of the Australian arid zone, and phylogenetic relationships are similar to divergence patterns found in other Australian arid taxa. The findings of this study suggest that aridification is more likely to be a driver of diversification in taxa with low dispersal potential than in those with high dispersal potential. This is because effective aerial dispersal is integral for maintaining gene flow when aquatic connections are lost between distant populations, and reduced gene flow can promote genetic divergence.

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A genotypically distinct, melanic variant of Anopheles arabiensi s in Sudan is associated with arid environments

Cited by 6 publications

References 58 publications

Identification of Spiroplasma insolitum symbionts in Anopheles gambiae

Identification of Spiroplasma insolitum symbionts in Anopheles gambiae

Anopheles arabiensis in Sudan: a noticeable tolerance to urban polluted larval habitats associated with resistance to Temephos

Evolutionary divergence in freshwater insects with contrasting dispersal capacity across a sea of desert

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