Biology subjects

Al-Amin, H. M.

Publications and source records attributed to Al-Amin, H. M..

4 recordsLinked to original sources

bioRxiv2025

A genomic toolkit for surveillance and elimination of the principal malaria vectors in Southeast Asia.

While substantial progress has been made toward malaria elimination in Southeast Asia, major challenges remain. The principal mosquito vectors, Anopheles dirus and Anopheles minimus, inhabit diverse ecological niches and exhibit a wide range of behavioural and physiological insecticide resistance phenotypes, complicating vector control efforts. In Africa, genomic surveillance has transformed our understanding of vector evolution and resistance, supported by open-access tools and data. Comparable resources for Southeast Asian vectors remain limited. Here, we release Adir1.0, a curated, analysis-ready catalog of 540 An. dirus whole-genome sequences, accessible for interactive cloud-based analysis via the malariagen-data-python application programming interface (API). Alongside, we provide an updated Amin1.0 API to enhance functionality and usability, enabling integrated analyses across historical and new datasets. We demonstrate these resources by performing the first exploratory population genomic analysis of An. dirus from Bangladesh, Thailand, and Cambodia, revealing population structure, candidate regions of physiological resistance, and genomic structural variation. Together, these resources provide a foundation for genomic surveillance studies to inform vector control and malaria elimination strategies in Southeast Asia.

genetics↗

bioRxiv2024

Fitness compatibility and dengue virus inhibition in a Bangladeshi strain of Aedes aegypti infected with the Wolbachia strain wAlbB

Dengue cases in Bangladesh have surged in recent years. The existing insecticide-based control program, implemented in parts of the country, is challenged by issues of insufficient household coverage and high levels of insecticide resistance in the primary dengue virus (DENV) vector, Aedes aegypti. A more sustainable, effective alternative could be the implementation of a Wolbachia-mediated disease management strategy. Infecting mosquitoes with Wolbachia can change their reproductive compatibility and their ability to transmit DENV. These new phenotypes can be exploited to suppress or replace wild-type Ae. aegypti populations. Such strategies require the development of well-characterised Wolbachia-infected strains with biological characteristics that are comparable with local mosquitoes. We created and characterised a Wolbachia-infected Ae. aegypti strain with a Dhaka wild-type genetic background, and compared its reproductive compatibility, maternal inheritance, fitness, and virus-blocking ability to the parental strains (Dhaka wild-type and wAlbB2-F4). The new Ae. aegypti strain wAlbB2-Dhaka demonstrated complete cytoplasmic incompatibility with the wild-type strain and complete maternal transmission, retaining levels of pyrethroid resistance of the Dhaka wild-type (70% survival to 10 times the dose of permethrin expected to kill susceptible mosquitoes). No significant fitness costs were detected during laboratory comparisons of fecundity, fertility, survival, mating competitiveness, or desiccation tolerance. Compared to the wild-type strain, wAlbB2-Dhaka mosquitoes had a significantly reduced number of DENV genome copies in the bodies (44.4%, p = 0.0034); two-fold reduction in dissemination to legs and wings (47.6%, p < 0.0001); and >13-fold reduction of DENV in saliva expectorates (proxy of transmission potential) (92.7%, p < 0.0001) 14 days after ingesting dengue-infected blood. Our work indicates that the wAlbB2-Dhaka strain could be used for Ae. aegypti suppression or replacement strategies for dengue management in Bangladesh. Author summaryBangladesh is currently grappling with a series of severe dengue outbreaks, resulting in more than 300 thousand infections, 1700 fatalities, and a significant influx of patients requiring hospitalisation in 2023. These outbreaks coincide with the emergence of high levels of insecticide resistance in the Ae. aegypti population, which is contributing to the failure of conventional, insecticidal control strategies. In search of more sustainable, effective dengue control strategies, approaches using the endosymbiotic bacteria Wolbachia that render mosquitoes resistant to arbovirus infection are being trialled in a number of countries. We transinfected Dhaka wild-type Ae. aegypti with the Wolbachia strain wAlbB2 by backcrossing it with a Wolbachia wAlbB2-infected Ae. aegypti strain and assessed the new strains suitability for field release. We compared the fitness and virus-blocking ability of the backcrossed strain with its parental strains. We demonstrated that the new strain, wAlbB2-Dhaka, is as fit as the Dhaka wild-type strain and blocked [~]92% of dengue virus transmission. This strain has great potential for Wolbachia-mediated dengue management strategies in Bangladesh.

zoology↗

bioRxiv2022

Genetic and microbial diversity of the invasive mosquito vector species Culex tritaeniorhynchus across its extensive inter-continental geographic range

Culex (Cx.) tritaeniorhynchus is a mosquito species with an extensive and expanding inter-continental geographic distribution, currently reported in over 50 countries, across Asia, Africa, the Middle East, Europe and now Australia. It is an important vector of medical and veterinary concern, capable of transmitting multiple arboviruses which cause significant morbidity and mortality in human and animal populations. In regions endemic for Japanese encephalitis virus (JEV) in Asia, Cx. tritaeniorhynchus is considered the major vector and this species has also been shown to contribute to the transmission of several other significant zoonotic arboviruses, including Rift Valley fever virus and West Nile virus. Significant variation in vectorial capacity can occur between different vector populations. Obtaining knowledge of a species from across its geographic range is crucial to understanding its significance for pathogen transmission across diverse environments and localities. Vectorial capacity can be influenced by factors including the mosquito genetic background, composition of the microbiota associated with the mosquito and the co-infection of human or animal pathogens. In addition to enhancing information on vector surveillance and potential risks for pathogen transmission, determining the genetic and microbial diversity of distinct populations of a vector species is also critical for the development and application of effective control strategies. In this study, multiple geographically dispersed populations of Cx. tritaeniorhynchus from countries within Europe, Africa, Eurasia and Asia were sampled. Molecular analysis demonstrated a high level of genetic and microbial diversity within and between populations, including genetic divergence in the mosquito CO1 gene, as well as diverse microbiomes identified by 16S rRNA gene amplicon sequencing. Evidence for the detection of the endosymbiotic bacteria Wolbachia in some populations was confirmed using Wolbachia-specific PCR detection and sequencing of Wolbachia MLST genes; in addition to PCR-based detection of insect-specific viruses. Laboratory vector competence showed Cx. tritaeniorhynchus from a Greek population are likely to be competent vectors of JEV. This study expands understanding of the diversity of Cx. tritaeniorhynchus across its inter-continental range, highlights the need for a greater focus on this invasive vector species and helps to inform potential future directions for development of vector control strategies.

genetics↗

bioRxiv2020

Insecticide resistance status of Aedes aegypti in Bangladesh

BackgroundArboviral diseases including dengue and chikungunya are major public health concern in Bangladesh, with unprecedented levels of transmission reported in recent years. The primary approach to control these diseases is control of Aedes aegypti using pyrethroid insecticides. Although chemical control is long-practiced, no comprehensive analysis of Ae. aegypti susceptibility to insecticides has previously been conducted. This study aimed to determine the insecticide resistance status of Ae. aegypti in Bangladesh and investigate the role of detoxification enzymes and altered target site sensitivity as resistance mechanisms. MethodsAedes eggs were collected using ovitraps from five districts across the country and in eight neighborhoods of the capital city Dhaka from August to November 2017. CDC bottle bioassays were conducted for permethrin, deltamethrin, malathion, and bendiocarb using 3-5-day old F0-F2 non-blood fed female mosquitoes. Biochemical assays were conducted to detect metabolic resistance mechanisms and real-time PCR was performed to determine the frequencies of the knockdown resistance (kdr) mutations Gly1016, Cys1534, and Leu410. ResultsHigh levels of resistance to permethrin were detected in all Ae. aegypti populations, with mortality ranging from 0 - 14.8% at the diagnostic dose. Substantial resistance continued to be detected against higher (2X) doses of permethrin (5.1 - 44.4% mortality). Susceptibility to deltamethrin and malathion varied between populations while complete susceptibility to bendiocarb was observed in all populations. Significantly higher levels of esterase and oxidase activity were detected in most of the test populations as compared to the susceptible reference Rockefeller strain. A significant association was detected between permethrin resistance and the presence of Gly1016 and Cys1534 homozygotes. The frequency of kdr alleles varied across the Dhaka populations, and Leu410 was not detected in any of the tested populations. ConclusionsThe detection of widespread pyrethroid resistance and multiple mechanisms highlights the urgency for implementing alternate Ae. aegypti control strategies. In addition, implementing routine monitoring of insecticide resistance in Ae. aegypti in Bangladesh will lead to a greater understanding of susceptibility trends over space and time, thereby enabling the development of improved control strategies.

microbiology↗