Dataset Information

Molecular forms of Anopheles subpictus and Anopheles sundaicus in the Indian subcontinent.

ABSTRACT: BACKGROUND:Anopheles subpictus and Anopheles sundaicus are closely related species, each comprising several sibling species. Ambiguities exist in the classification of these two nominal species and the specific status of members of these species complexes. Identifying fixed molecular forms and mapping their spatial distribution will help in resolving the taxonomic ambiguities and understanding their relative epidemiological significance. METHODS:DNA sequencing of Internal Transcribed Spacer-2 (ITS2), 28S-rDNA (D1-to-D3 domains) and cytochrome oxidase-II (COII) of morphologically identified specimens of two nominal species, An. subpictus sensu lato (s.l.) and An. sundaicus s.l., collected from the Indian subcontinent, was performed and subjected to genetic distance and molecular phylogenetic analyses. RESULTS:Molecular characterization of mosquitoes for rDNA revealed the presence of two molecular forms of An. sundaicus s.l. and three molecular forms of An. subpictus s.l. (provisionally designated as Form A, B and C) in the Indian subcontinent. Phylogenetic analyses revealed two distinct clades: (i) subpictus clade, with a single molecular form of An. subpictus (Form A) prevalent in mainland India and Sri Lanka, and (ii) sundaicus clade, comprising of members of Sundaicus Complex, two molecular forms of An. subpictus s.l. (Form B and C), prevalent in coastal areas or islands in Indian subcontinent, and molecular forms of An. subpictus s.l. reported from Thailand and Indonesia. Based on the number of float-ridges on eggs, all An. subpictus molecular Form B were classified as Species B whereas majority (80%) of the molecular Form A were classified as sibling species C. Fixed intragenomic sequence variation in ITS2 with the presence of two haplotypes was found in molecular Form A throughout its distribution. CONCLUSION:A total of three molecular forms of An. subpictus s.l. and two molecular forms of An. sundaicus s.l. were recorded in the Indian subcontinent. Phylogenetically, two forms of An. subpictus s.l. (Form B and C) prevalent in coastal areas or islands in the Indian subcontinent and molecular forms reported from Southeast Asia are members of Sundaicus Complex. Molecular Form A of An. subpictus is distantly related to all other forms and deserve a distinct specific status.

SUBMITTER: Sindhania A

PROVIDER: S-EPMC7678295 | biostudies-literature | 2020 Nov

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Molecular forms of Anopheles subpictus and Anopheles sundaicus in the Indian subcontinent.

Sindhania Ankita A Das Manoj K MK Sharma Gunjan G Surendran Sinnathamby N SN Kaushal B R BR Lohani Himanshu P HP Singh Om P OP

Malaria journal 20201119 1

<h4>Background</h4>Anopheles subpictus and Anopheles sundaicus are closely related species, each comprising several sibling species. Ambiguities exist in the classification of these two nominal species and the specific status of members of these species complexes. Identifying fixed molecular forms and mapping their spatial distribution will help in resolving the taxonomic ambiguities and understanding their relative epidemiological significance.<h4>Methods</h4>DNA sequencing of Internal Transcri ...[more]

PMID: 33213479

Similar Datasets

Project description:Antimonials (Sb) were used for decades for chemotherapy of visceral leishmaniasis (VL). Now abandoned in the Indian subcontinent (ISC) because of Leishmania donovani resistance, this drug offers a unique model for understanding drug resistance dynamics. In a previous phylogenomic study, we found two distinct populations of L. donovani: the core group (CG) in the Gangetic plains and ISC1 in the Nepalese highlands. Sb resistance was only encountered within the CG, and a series of potential markers were identified. Here, we analyzed the development of resistance to trivalent antimonials (SbIII) upon experimental selection in ISC1 and CG strains. We observed that (i) baseline SbIII susceptibility of parasites was higher in ISC1 than in the CG, (ii) time to SbIII resistance was higher for ISC1 parasites than for CG strains, and (iii) untargeted genomic and metabolomic analyses revealed molecular changes along the selection process: these were more numerous in ISC1 than in the CG. Altogether these observations led to the hypothesis that CG parasites are preadapted to SbIII resistance. This hypothesis was experimentally confirmed by showing that only wild-type CG strains could survive a direct exposure to the maximal concentration of SbIII The main driver of this preadaptation was shown to be MRPA, a gene involved in SbIII sequestration and amplified in an intrachromosomal amplicon in all CG strains characterized so far. This amplicon emerged around 1850 in the CG, well before the implementation of antimonials for VL chemotherapy, and we discuss here several hypotheses of selective pressure that could have accompanied its emergence.IMPORTANCE The "antibiotic resistance crisis" is a major challenge for scientists and medical professionals. This steady rise in drug-resistant pathogens also extends to parasitic diseases, with antimony being the first anti-Leishmania drug that fell in the Indian subcontinent (ISC). Leishmaniasis is a major but neglected infectious disease with limited therapeutic options. Therefore, understanding how parasites became resistant to antimonials is of commanding importance. In this study, we experimentally characterized the dynamics of this resistance acquisition and show for the first time that some Leishmania populations of the ISC were preadapted to antimony resistance, likely driven by environmental factors or by drugs used in the 19th century.

Project description:BACKGROUND:Although Sri Lanka is considered as a malaria-free nation, the threat of re-emergence of outbreaks still remains due to the high prevalence and abundance of malaria vectors. Analysis of population genetic structure of malaria vectors is considered to be one of the vital components in implementing successful vector control programmes. The present study was conducted to determine the population genetic structure of three abundant malaria vectors; Anopheles subpictus sensu lato (s.l.), Anopheles peditaneatus and Anopheles vagus from five administrative districts in two climatic zones; intermediate zone (Badulla and Kurunegala districts) and dry zone (Ampara, Batticoloa and Jaffna districts) of Sri Lanka using the mitochondrial gene, cytochrome c oxidase subunit I (COI). METHODS:Adult mosquitoes of An. subpictus s.l., An. peditaeniatus, and An. vagus were collected from five study sites located in five districts using cattle baited traps and backpack aspirators. Representative samples of each species that were morphologically confirmed were selected from each locality in generating COI sequences (>?6 good quality sequences per species per locality). RESULTS:Anopheles subpictus s.l. specimens collected during the study belonged to two sibling species; An. subpictus 'A' (from all study sites except from Jaffna) and An. subpictus 'B' (only from Jaffna). The results of haplotype and nucleotide diversity indices showed that all the three species are having high genetic diversity. Although a high significant pairwise difference was observed between An. subpictus 'A' and 'B' (Fst>?0.950, p?<?0.05), there were no significant genetic population structures within An. peditaeniatus, An. vagus and An. subpictus species A (p?>?0.05), indicating possible gene flow between these populations. CONCLUSIONS:Gene flow among the populations of An. peditaeniatus, An. vagus and An. subpictus species A was evident. Application of vector control measures against all mosquito species must be done with close monitoring since gene flow can assist the spread of insecticide resistance genes over a vast geographical area.

Project description:Plasmodium vivax is the most widely distributed human malaria parasite and accounts for approximately the same number of malaria cases as Plasmodium falciparum in India. Compared with P. falciparum, P. vivax is difficult to eradicate because of its tendency to cause relapses, which impacts treatment and control strategies. The genetic diversity of these parasites, particularly of the merozoite surface protein-3 alpha (msp-3?) gene, can be used to help develop a potential vaccine. The present study aimed to investigate the genetic diversity of P. vivax using the highly polymorphic antigen gene msp-3? and to assess the suitability of using this gene for population genetic studies of P. vivax isolates and was carried out in 2004-06. No recent study has been reported for MSP 3? in the recent decade in India. Limited reports are available on the genetic diversity of the P. vivax population in India; hence, this report aimed to improve the understanding of the molecular epidemiology of the parasite by studying the P. vivax msp-3? (Pvmsp-3?) marker from P. vivax field isolates from India.Field isolates were collected from different sites distributed across eight states in India. A total of 182 blood samples were analysed by a nested polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique using the HhaI and AluI restriction enzymes to determine genetic msp-3? variation among clinical P. vivax isolates.Based on the length variants of the PCR products of Pvmsp-3? gene, three allele sizes, Type A (1.8 kb), Type B (1.5 kb) and Type C (1.2 kb) were detected among the 182 samples. Type A PCR amplicon was more predominant (75.4 %) in the samples compared with the Type B (14.3 %) and Type C (10.0 %) polymorphisms. Among all of the samples analysed, 8.2 % were mixed infections detected by PCR alone. Restriction fragment length polymorphism (RFLP) analysis involving the restriction enzymes AluI and HhaI generated fragment sizes that were highly polymorphic and revealed substantial diversity at the nucleotide level.The present study is the first extensive study in India using the Pvmsp-3? marker. The results indicated that Pvmps-3?, a polymorphic genetic marker of P. vivax, exhibited considerable variability in infection prevalence in field isolates from India. Additionally, the mean multiplicity of infection observed at all of the study sites indicated that P. vivax is highly diverse in nature in India, and Pvmsp-3? is likely an effective and promising epidemiological marker.

Dataset Information

Molecular forms of Anopheles subpictus and Anopheles sundaicus in the Indian subcontinent.

Publications

Molecular forms of Anopheles subpictus and Anopheles sundaicus in the Indian subcontinent.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets