Keywords: Asia
Mark–release–recapture study of irradiated male Aedes albopictus under stressful field conditions
35492Qingdeng Feng, Ming Li, Jeremy Bouyer, et al., Pest Management Science, 2026-03-09 10:33:54.
The sterile insect technique (SIT) suppresses mosquito populations by releasing sterile males. Its success mainly depends on the performance of sterile males. Mark–Release–Recapture (MRR) experiments are used to evaluate male performance in the field, yet most previous experiments were conducted under mild conditions (e.g. 25–28 °C) in which mosquitoes could easily adapt. Male mosquito performance under stressful field conditions remains poorly understood. This study evaluated the field performance of irradiated Aedes albopictus males under high-temperature conditions (>30 °C in average) in southern China, Foshan City, located in a sub-tropical area. Two MRR experiments were conducted in a 5-ha village during July–August of 2023 and 2024. Lifespan and dispersal of postreleased males were examined using BG-Sentinel mosquito traps, human landing catches, and ovitraps. A total of 54 546 and 58 440 sterile males were released in 2023 and 2024, respectively, with recapture rates of 8.53% and 5.64%. The mean dispersal distances ranged from 58.88–77.19 m (2023) to 81.82–90.86 m (2024). Daily survival probabilities were 0.15–0.28 in 2023 and 0.45–0.62 in 2024, corresponding to average expected lifespans of 0.53–0.78 days and 1.26–2.13 days, respectively. Estimated wild male densities ranged from 302–986 males ha−1 in 2023 to 416–3785 males ha−1 in 2024. Stressful field conditions severely reduced sterile male survival and dispersal, highlighting the need to optimize release protocols in challenging climates. These findings provide critical baseline data for advancing Ae. albopictus SIT programmes in southern China.
Dengue Suppression by Male Wolbachia-Infected Mosquitoes
35443Jue Tao Lim, Ph.D., Chee-Seng Chong, Ph.D., Chia-Chen Chang, Ph.D., et al., New England Journal of Medicine, 2026-02-12 17:46:04.
Wild-type female Aedes aegypti mosquitoes that mate with male A. aegypti mosquitoes that have been infected with the wAlbB strain of Wolbachia pipientis bacteria produce nonviable offspring owing to cytoplasmic incompatibility. Repeated releases of wolbachia-infected males can potentially suppress wild-type mosquito populations and reduce the risk of dengue virus infection. We conducted a trial involving the release of male A. aegypti mosquitoes infected with the wAlbB strain of wolbachia bacteria for the control of dengue in Singapore, a tropical city-state. In this cluster-randomized trial with test-negative controls, we divided 15 geographic population clusters into two groups: 8 clusters received deployments of male wolbachia-infected mosquitoes (intervention clusters) and 7 clusters received no deployments (control clusters). The primary end point was the diagnosis of symptomatic dengue virus infection of any severity caused by any serotype of the virus, as measured by the odds ratio for the distribution of wolbachia exposure among laboratory-confirmed reported dengue cases as compared with test-negative controls. A total of 393,236 residents lived in the intervention clusters, and 331,192 lived in the control clusters. Adult wild-type A. aegypti populations were suppressed across the intervention clusters. The baseline average abundance of the mosquitoes (number of adult female mosquitoes trapped divided by number of traps) was 0.18 and 0.19 in the intervention and control clusters, respectively; from 3 months after the initiation of the intervention until the end of the 24-month trial period, the average abundance was 0.041 and 0.277, respectively. In the intention-to-treat analysis at 6 months or more, the percentage of residents in the intervention clusters who were dengue-positive was lower than that in the control clusters (354 of 5722 tests [6%] vs. 1519 of 7080 tests [21%]). The protective efficacy of the intervention, calculated as (1−odds ratio)×100, ranged from 71 to 72% with 3 to 12 months or more of wolbachia mosquito exposure, as represented by odds ratios of 0.28 to 0.29. Release of sterile wolbachia-infected male A. aegypti mosquitoes reduced vector populations and the risk of dengue infection in Singapore.
Wolbachia mosquito release cuts dengue cases 50–80 percent
35437Mohamad Al As, Zaf Seraj, New Straits Times, 2026-01-27 18:26:15.
The release of Wolbachia-infected Aedes mosquitoes has led to a 50 to 80 per cent drop in dengue cases in several outbreak areas in Selangor, the Dewan Rakyat was told. Health Minister Datuk Seri Dr Dzulkefly Ahmad said public health studies conducted during the early phase of the programme showed encouraging results. "During the early phase of implementation, the results of public health studies in six dengue outbreak localities in Selangor showed a reduction in dengue cases between 50 per cent and 80 per cent compared with control localities," he said in a written parliamentary reply last night. He was responding to Mohd Hasnizan Harun (PN-Hulu Selangor), who asked whether the ministry has conducted comprehensive environmental and public health impact studies related to the release of Wolbachia-infected mosquitoes. Hasnizan also asked about continuous monitoring mechanisms to ensure long-term safety. Dzulkefly said the early assessments also examined the interaction between Wolbachia-infected Aedes mosquitoes and the existing mosquito population in the environment.
Genetic Biocontrol Strategy Considerations for Mosquito Control in the Pacific Island Countries and Territories
35315Adam E. Vorsino, Tim Harvey-Samuel, Limb K. Hapairai, et al., Current Opinion in Insect Science, 2026-01-05 10:49:54.
Mosquito-borne diseases pose an existential threat to the health, economies, and unique ecosystems of Pacific Island Countries and Territories (PICTs). The remoteness of these islands, combined with the presence of highly competent mosquito vectors, complicates disease surveillance and vector control efforts. In response, the PICTs have become a focal point for the development and application of Genetic BioControl (GBC) technologies designed to break vector-borne disease transmission cycles. However, the application of GBC tools in this region warrants careful consideration of its unique history, including a legacy of colonialism, and challenges associated with logistic hurdles. Through meaningful community engagement and authentic collaborations, drawing from local knowledge, and building local capacity, the sustainable, efficient and effective deployment of GBC tools may be achieved.
Rethinking the future of mosquito control
35341Kabirul Bashar, Dr Zonaed Siddiki. Dr Zonaed Siddiki, et al., Dhaka Tribune, 2025-12-17 11:37:26.
Bangladesh is once again in the grip of a severe dengue and chikungunya crisis in 2025. Hospitals are overwhelmed, fever wards are full, and doctors are working tirelessly. Families live in fear of mosquito bites, while daily news reports chronicle rising infections and deaths. As of December 16, 2025, the Directorate General of Health Services (DGHS) has reported more than 100,000 confirmed dengue cases and 409 deaths. However, this figure represents only the tip of the iceberg, as it reflects data solely from hospitalized patients, specifically from 77 hospitals in Dhaka and reports from 64 civil surgeon offices. A substantial number of dengue patients are receiving treatment at home or in various small and large hospitals and clinics that are not included in the official count. This underscores the overwhelming pressure on the country’s health system. At the same time, the Institute of Epidemiology, Disease Control and Research (IEDCR) has recorded a resurgence of chikungunya, reporting 337 suspected cases, 153 of which were laboratory-confirmed in Dhaka between January and May 2025. Researchers estimate that the true number of chikungunya infections this year may be close to one hundred thousand. As chikungunya testing is available only in a limited number of major hospitals in Dhaka, many cases remain undiagnosed and unreported.
Wolbachia Infection in Iranian Malaria Vectors: Prevalence and Biocontrol Implications
35124Shahin Saeedi, Fateh Karimian, Seyed Hassan Moosa-Kazemi, et al., Tropical Medicine & International health, 2025-09-08 08:50:24.
Wolbachia-based vector control is an emerging tool in malaria prevention research. This study evaluates Wolbachia infection in Iranian mosquitoes, focusing on seven known malaria vectors. Mosquitoes were collected from nine provinces of Iran (2016–2019), and Wolbachia infection status was analysed via PCR targeting eight genes: wsp, gatB, ftsZ, dnaA, groEL, gltA, CoxA and fbpA. We examined 1094 specimens from seven malaria vectors (Anopheles stephensi Liston, 1901; Anopheles culicifacies s.l. James, 1901; Anopheles fluviatilis s.l. James, 1902; Anopheles maculipennis s.l. Meigen, 1818; Anopheles sacharovi Favr, 1903; Anopheles dthali Patton, 1905; Anopheles superpictus s.l. Grassi, 1899), four non-malaria vectors (Anopheles mongolensis Linton, Lee and Curtis, 2005; Anopheles hyrcanus Pallas, 1771; Anopheles claviger Meigen, 1804; Anopheles turkhudi Liston, 1901) and three Culex species (Culex pipiens Linnaeus, 1758; Culex perexiguus Theobald, 1903; Culex theileri Theobald, 1903). PCR revealed Wolbachia DNA exclusively in An. dthali and Culex species, with infection rates of 73.4% for An. dthali and 77.78%–96.77% for Culex, notably higher in males. Wolbachia was detected in all regions except one in the north. Phylogenetic analysis revealed Wolbachia strains in An. dthali and Culex belong to supergroup B, closely related to strains in An. moucheti and An. demeilloni. This suggests broader applications for biocontrol strategies. The high Wolbachia prevalence in An. dthali is promising for malaria prevention. Future research should confirm cytoplasmic incompatibility and explore wAdth's potential to block malaria transmission.
Application of Sterile Insect Technique (SIT) for Aedes albopictus (Skuse, 1895) in Sri Lanka: Dose optimization, mating competitiveness and release ratios
35114Harishchandra J, Abeyewickreme W, Premaratne R, Hapugoda M, PLoS One, 20. 2025-09-05 08:04:10.
Sri Lanka has experienced severe dengue epidemics in recent years, despite the extensive vector control measures taken. Therefore, it is necessary to find sustainable vector control strategies against dengue. Novel vector control tools need to be tested for the feasibility of applying them against local vectors. Sterile Insect Technique (SIT) is an increasingly popular vector control technique which has been adopted by many countries to suppress insect pest populations and is being tested for dengue vectors. In this study, SIT was developed for Aedes albopictus (Skuse, 1895), one of the 2 dengue vectors present in Sri Lanka. The optimum radiation dose for sterilizing male pupae (age 24–48 hours) using a Co 60 source was determined based on the post-irradiation pupal and adult survival in males and induced sterility in females at different doses. Further, the effect of irradiation on mating competitiveness of the selected mosquito strain was assessed under laboratory and semi-field conditions. The optimum release ratio of irradiated males to wild males was assessed in laboratory and semi-field settings. The optimum radiation dose was 50 Gy among the series of doses (25, 30, 40, 50, 60, and 70 Gy) tested. When pupae were exposed to the optimal radiation dose, 100% pupal survival, 19-day median adult survival time and 99% induced sterility resulted. A 5:1 ratio of irradiated males to non-irradiated laboratory-reared or wild males in laboratory cages resulted in induced sterility of 75% and 62%, respectively. The respective values were 74% and 61% in large semi-field cages. Fried Competitiveness Index (FCI) of irradiated males against wild males of laboratory and wild origin were 0.63 and 0.43 in laboratory cages and 0.57 and 0.55 in large semi-field cages. The males of Ae. albopictus irradiated at 50 Gy are adequately sterile and are competitive against the wild males. The release ratio of 5:1 irradiated males to wild males is a suitable ratio for the field application of SIT. The findings of the study will be important for the development of a protocol for future application of SIT for Ae. albopictus in Sri Lanka.
Knowledge, attitude, and practice (KAP), and acceptance and willingness to pay (WTP) for mosquito-borne diseases control through sterile mosquito release in Bangkok, Thailand
34991Kittayapong P, Ninphanomchai S, Jalichandra N, Sringernyuang L, Sherer P, Meemon N, PLoS Negl Trop Dis, 19. 2025-07-30 11:03:04.
A questionnaire survey was conducted in seven communities in Bangkok, Thailand to obtain baseline information on knowledge, attitudes and practices (KAP) related to mosquito-borne diseases, i.e., dengue, chikungunya and Zika, including mosquito vectors and how to control them. The questionnaire also asked about the acceptance and willingness to pay (WTP) for sterile mosquitoes used in controlling mosquito populations. Our results showed that, from a total of 400 sampling households, about 85% of participants were familiar with dengue and its mosquito vectors, as well as their prevention and control. Furthermore, participants with lower ages and higher incomes had more knowledge on mosquito vectors (p < 0.05). Even though the majority of participants did not have any knowledge on sterile mosquito release, they showed a positive perception about it. However, more than half of them were not willing to pay for sterile mosquitoes, since they would like to receive them as public support from the government. If they were to pay, the cost that they could afford was 1–2 THB (~US$ 0.03- 0.06) per sterile mosquito. These findings should be useful for public health authorities when planning to apply the sterile mosquito release as an alternative mosquito control approach in Bangkok, Thailand.
Integrated vector management with the sterile insect technique component for the suppression of Aedes aegypti in an urban setting in Indonesia
34954Sasmita HI, Neoh K-B, Ernawan B, Indarwatmi M, Nasution IA, Fitrianto N, et al., PLoS Neglected Tropical Diseases, 2025-07-08 13:14:26.
The sterile insect technique (SIT) involves subjecting laboratory-bred male mosquitoes to radiation, typically gamma rays, X-rays, or electrons, that render them sterile. These sterile male mosquitoes are then released into the field to mate with wild female mosquitoes. From that mating, no viable eggs are produced. The SIT is a mosquito population control strategy that prevents the spread of the dengue virus through Aedes aegypti female mosquitoes. Considerable progress has been made regarding the SIT, and its effectiveness has been tested in numerous regions for managing local mosquito populations. In the present study, the field performance of sterile male mosquitoes was evaluated through a mark–release–recapture study, which was followed by an SIT trial. In an SIT pilot trial, pre-release control measures, including insecticide application and mosquito breeding site removal, were applied within the framework of integrated vector management. Community engagement activities were designed to ensure community acceptance and support for the SIT. The trial led to substantial reductions in the egg hatching, numbers of eggs and female mosquitoes despite challenges related to sterile male production and population isolation. This study revealed the key factors contributing to the success of an SIT trial to be the field performance of sterile male mosquitoes, complementary vector control methods, population isolation, and support from local residents.
Mosquito Miracle: Breakthrough Brings Hope for Bangladesh in Dengue Fight
34837Staff Correspondent, Digi Bangla Tech, 2025-05-10 19:42:52.
A major scientific breakthrough is offering new hope for Bangladesh in its battle against dengue. An international team of researchers has successfully developed a strain of Aedes aegypti mosquitoes infected with Wolbachia bacteria, which are capable of adapting to the local environment of Dhaka city. Dubbed as “good mosquitoes,” this innovation opens a new, safe, and biological pathway for controlling the spread of dengue and other mosquito-borne arboviral diseases in the country, according to the International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b). The research team includes scientists from QIMR Berghofer Medical Research Institute in Australia, the University of Queensland, icddr,b, and the United States Centers for Disease Control and Prevention. The findings were recently published in the journal Nature’s Scientific Reports. According to icddr,b, dengue has emerged as a severe public health threat in Bangladesh. In 2023 alone, a record 321,000 people were infected, with more than 1,700 deaths—making it the deadliest year on record. Rapid urbanization, erratic rainfall, and rising temperatures have contributed to the spread of Aedes mosquitoes, the primary vector of dengue. Simultaneously, the effectiveness of conventional insecticide-based mosquito control methods is declining due to growing resistance among mosquito populations. This has prompted scientists worldwide to seek more sustainable solutions, with the use of "good mosquitoes" being one of the most promising. Researchers explained that Wolbachia was chosen because it prevents Aedes mosquitoes from transmitting dengue, chikungunya, and Zika viruses, without harming humans or the environment. Wolbachia is a naturally occurring bacterium found in butterflies, fruit flies, and some mosquito species, though not in Aedes aegypti. This bacterium cannot infect humans or animals, nor is it transmissible through bites or contact.
Impact of sterile Aedes aegypti males releases on vector dynamics: insights from Malaysian field trials
34815Nazni, W.A., Teoh, GN., Nuradila, M.A. et al., Infectious Diseases of Poverty, 14. 2025-05-04 16:00:48.
The Sterile insect technique (SIT) has been successfully used in agricultural pest control, leading to interest in its application for public health, particularly in controlling Aedes mosquitoes in the USA, Italy, Cuba, and Greece. Malaysia has conducted a small-scale SIT pilot trial since 2019 for dengue control. This study evaluates mosquito populations in treated and untreated sites through three objectives: (1) comparing mean larvae per trap (MLT) and dengue cases for Ae. aegypti and Aedes albopictus; (2) estimating survival rates and wild populations using mark-release-recapture (MRR); and (3) analysing spatial distribution in treated and untreated sites. Ae. aegypti males, irradiated at 55 Gray, were released in three locations: Pangsapuri Kota Laksamana (KT), Malacca (19 months), Pangsapuri Taman Tasik Utama (TTU), Malacca (8 months), and the Customs, Immigration, and Quarantine Complex (CIQ), Johor (7 months). Statistical analyses assessed SIT effectiveness, including T-tests for larval density and ovitrap indices, Mulla’s formula and relative variance (RV) for population reduction, and the Lincoln Index for estimating wild male populations and probability of daily survival. Weekly releases of sterile Ae. aegypti males at doses of 1278–7942 males/ha achieved a sterile-to-wild male ratio of 5.85 and a mean daily survival rate of 0.61, leading to significant reductions in larval densities: 76.25% in Kota Laksamana (KT), 96.74% in Taman Tasik Utama (TTU), and 89.00% in CIQ Gelang Patah, thereby supporting dengue control efforts. In KT, the MLT was initially low but increased, although with suppression < 90%, there was a reduce of dengue cases throughout the release period. The MRR’s mean survival rate (± standard deviation) in KT was 0.61 (± 0.08). The spatial clustering of Ae. aegypti was observed in central blocks during the high MLT period. However, larval densities rebounded after releases ceased. Spatial clustering revealed no initial clustering, though clustering patterns emerged over time in KT. SIT effectively suppressed Ae. aegypti populations and supported dengue control. Optimizing sterile-to-wild male ratios, spatial distribution, and monitoring strategies is essential for sustainable vector control. These findings provide insights for scaling up SIT field trials, with future efforts focusing on refining release and monitoring strategies to enhance SIT as an effective dengue control tool. Trial registration NMRR-17–2652-39,099 “Field evaluation of Sterile Insect for Aedes aegypti Suppression.”
Adjacent spillover efficacy of Wolbachia for control of dengue: emulation of a cluster randomised target trial
34679Lim, J.T., Mailepessov, D., Chong, C.S. et al., BMC Medicine, 23. 2025-03-28 08:29:31.
Matings between male Aedes aegypti mosquitoes infected with wAlbB strain of Wolbachia and wild-type females yield non-viable eggs, thereby suppressing Ae. aegypti abundance in the field. We evaluated the spillover efficacy of releasing wAlbB-infected Ae. aegypti male mosquitoes to suppress dengue in sites adjacent to release sites (spillover sites). The protocol of a two-arm cluster-randomised test-negative controlled trial (cRCT) was specified and emulated using a nationally representative dengue test-negative/positive database of 454,437 individuals reporting for febrile illness to primary or secondary care in public healthcare institutions. Spillover intervention sites were defined by geolocating locations which were adjacent to, i.e. shared geographical borders with, actual Wolbachia intervention sites. We built a cohort of individuals who resided in spillover sites versus a comparator control group who resided in sites which did not receive Wolbachia interventions. We emulated a constrained randomisation protocol used in cRCTs to balance dengue risk between spillover and control arms in the pre-intervention period. We matched individuals reporting for testing in intervention and control groups by calendar time and a high-dimensional battery of sociodemographic, environmental and anthropogenic variables. Intention-to-treat analysis was conducted to estimate the protective efficacy against dengue given spillover Wolbachia exposure. The final cohort consisted of 2354 matched individuals residing in Wolbachia spillover and control sites for at least 3 months in the study period. Compared to the controls, individuals residing in spillover sites for 3 or more months were associated with a 45% (OR: 0.55, 95% CI: 0.42‒0.74) reduction in risk of contracting dengue. Higher durations of spillover Wolbachia exposure also modestly increased protective efficacies. Compared to the control arm, the proportion of virologically confirmed dengue cases was lower in the spillover arm overall and across each subgroup. Protective efficacies were found across all years, age and sex subgroups. Our results demonstrated the potential of Wolbachia-mediated sterility for reducing the risk of contracting dengue even in sites which were not directly treated by the intervention.
Progress made for blackchin tilapia control in Thailand
34535The Fish Site, 2025-02-21 11:50:45.
Despite tilapia being one of the most widely farmed fish in the global aquaculture industry, invasive populations of the blackchin tilapia - a cichlid native to West Africa - have been devastating the productivity of aquaculture operations throughout Thailand. However, a multi-stakeholder effort led by the country's Department of Fisheries has reported progress towards controlling this invasive species, turning an environmental challenge into a pathway for sustainable development and local economic growth. Forming part of a five-point government strategy to address the ecological challenges posed by invasive species, the Department of Fisheries has developed a specially engineered strain known as Blackchin Tilapia 4n - a genetically modified variant designed to inhibit reproduction. The experimental strain has been released at experimental sites this month to evaluate its effectiveness in reducing the invasive fish population. Simultaneously, another project is specifically geared towards assisting aquaculture producers. The Seabass Fund for Farmers assists farmers in reducing costs by introducing natural predators into aquaculture ponds, effectively managing the blackchin tilapia population. This programme was established by the Phetchaburi Provincial Fisheries Office to support small-scale farmers with revolving funds for purchasing seabass fingerlings, providing a sustainable solution for shrimp, fish, and crab farmers operating in semi-natural systems to control and reduce populations of the invasive cichlid. In addition to direct eradication efforts, the promotion of blackchin tilapia products, such as foods and feeds, is being used to encourage consumption of the fish, driving local economic growth. These initiatives have been implemented by Charoen Pokphand Foods throughout 2024, including the purchase of 2 million kilograms of Blackchin tilapia for fishmeal production. Charoen Pokphand has also extended assistance to fishing activities aimed at blackchin tilapia removal by supplying fishing equipment and necessary materials to participants. If successful, these programmes for the control of blackchin tilapia populations in Thailand could serve as a model for governmental and private-sector cooperation for environmental solutions and local economic development.
Suppression of Aedes aegypti may not affect sympatric Aedes albopictus populations: findings from two years of entomological surveillance in Singapore
34497Wong, W.J., Tan, C.H., Verkaik, M.G. et al., Scientific Reports, 15:2253. 2025-02-04 19:28:45.
Globally, multiple trials have successfully demonstrated the effectiveness of novel tools, such as the sterile and incompatible insect techniques, in suppressing Aedes aegypti populations. However, there is concern that Aedes albopictus, another arbovirus-competent vector, may occupy the niches vacated by Ae. aegypti in areas where these species occur in sympatry. Here we investigate these concerns within the context of a Wolbachia-based Ae. aegypti suppression programme in highly urban Singapore, where general mosquito management is sustained through environmental management. Using nationally representative and longitudinal Aedes surveillance data, we show (1) no consistent association of increase in Ae. albopictus abundance with Ae. aegypti population suppression within Wolbachia-Aedes release sites, and (2) no significant change in the vertical spatial distribution of Ae. albopictus in high-rise residential apartment blocks even after two years of Ae. aegypti suppression. Finally, we report that dengue viruses were less prevalent in field Ae. albopictus than in Ae. aegypti, which is consistent with previous findings that Ae. albopictus is a lesser vector than Ae. aegypti in Singapore. Together, these results indicate that suppression of Ae. aegypti in the community may not be directly associated with any increase of Ae. albopictus population or capacity. Nonetheless, the risk of increase in Ae. albopictus population is anticipated if the reduction in disease transmission leads to less aggressive source reduction efforts and environmental management for mosquito control.
Explained | The problem with India’s new guidelines on genetically modified insects
26274S. Naik, The Hindu, 2023-06-27 10:35:38.
India’s bioeconomy contributes 2.6% to the GDP. In April 2023, the Department of Biotechnology (DBT) released its ‘Bioeconomy Report 2022’ report, envisioning this contribution to be closer to 5% by 2030. This ambitious leap – of $220 billion in eight years – will require aggressive investment and policy support. But neither funding for the DBT, India’s primary promoter of biotechnology, nor its recent policies reflect any serious intention to uplift this sector. Along with more money, policies that enable risk-taking appetite within Indian scientists will be required to create an ecosystem of innovation and industrial action. Funding for biotechnology India has been stagnating for a while. Despite a slight uptick during COVID-19, when DBT led the vaccine and diagnostics efforts, funding hasn’t returned to the pre-pandemic level. The current allocation is also only 0.0001% of India’s GDP, and it needs to be significantly revised if biotechnology is to be of any serious consequence for the economy.Funding aside, biotechnology policies also need to be aligned to the economic goals set out in the Bioeconomy report. However, the language in a set of guidelines that the Indian government released recently, pertaining to genetically edited insects, indicate a problem. In April 2023, the Department of Biotechnology (DBT) issued the ‘Guidelines for Genetically Engineered (GE) Insects’. They provide procedural roadmaps for those interested in creating GE insects. They have three issues, however.
Guidelines and Standard Operating Procedures for Research on Genetically Engineer Insects, 2023
26270Government of India, Government of India, 2023-04-17 09:55:34.
Department of Biotechnology, Government of India is delighted to release "Guidelines and Standard Operating Procedures for Research on Genetically Engineered Insects, 2023". This document is pertinent for enabling potential of genetic engineering in insect research to revolutionize the field of entomology, understanding of role of insects in ecosystems as well as their interactions with humans. These guidelines and standard operating procedures are intended to provide guidance on regulatory requirement and data requirement of genetic engineering research on insects under containment conditions.
Gene Drives and Vector-Borne Diseases: A Comparative Perspective Using Malaria as a Case Study
24818S. Todi, The Takshashila Institution, 2023-03-07 15:51:15.
Gene drives are an emerging technological application to reduce the prevalence of vector-borne diseases, crop pests, and non-native invasive species. This method for vector control is currently at the research stage, with parallel community engagement programmes being carried out in African countries to raise awareness for its adoption. Yet, the risks associated with using gene drives may go beyond the communities they are deployed in. Hence, it is critical for India to understand the relevance of gene drive application in India and its neighboring countries to create effective policy measures for achieving control of vector-borne diseases. Using malaria as a case study, we argue that India currently does not require the use of gene drives to achieve control of mosquito-borne diseases. However, India should invest in research for gene drives and vaccines, while continuing with current efforts to curb vector-borne diseases. Further, India will need strong data monitoring systems to identify if any gene drive mosquitoes deployed by other countries make their way to India.
Impact of randomised wmel Wolbachia deployments on notified dengue cases and insecticide fogging for dengue control in Yogyakarta City
24619C. Indriani, S. K. Tanamas, U. Khasanah, M. R. Ansari, Rubangi, W. Tantowijoyo, R. A. Ahmad, S. M. Dufault, N. P. Jewell, A. Utarini, C. P. Simmons and K. L. Anders, Glob Health Action, 16:2166650. 2023-01-26 09:27:00.
BACKGROUND: Releases of Wolbachia (wMel)-infected Aedes aegypti mosquitoes significantly reduced the incidence of virologically confirmed dengue in a previous cluster randomised trial in Yogyakarta City, Indonesia. Following the trial, wMel releases were extended to the untreated control areas, to achieve city-wide coverage of Wolbachia. OBJECTIVE: In this predefined analysis, we evaluated the impact of the wMel deployments in Yogyakarta on dengue hemorrhagic fever (DHF) case notifications and on the frequency of perifocal insecticide spraying by public health teams. METHODS: Monthly counts of DHF cases notified to the Yogyakarta District Health Office between January 2006 and May 2022 were modelled as a function of time-varying local wMel treatment status (fully- and partially-treated vs untreated, and by quintile of wMel prevalence). The frequency of insecticide fogging in wMel-treated and untreated areas was analysed using negative binomial regression. RESULTS: Notified DHF incidence was 83% lower in fully treated vs untreated periods (IRR 0.17 [95% CI 0.14, 0.20]), and 78% lower in areas with 80-100% wMel prevalence compared to areas with 0-20% wMel (IRR 0.23 [0.17, 0.30]). A similar intervention effect was observed at 60-80% wMel prevalence as at 80-100% prevalence (76% vs 78% efficacy, respectively). Pre-intervention, insecticide fogging occurred at similar frequencies in areas later randomised to wMel-treated and untreated arms of the trial. After wMel deployment, fogging occurred significantly less frequently in treated areas (IRR 0.17 [0.10, 0.30]). CONCLUSIONS: Deployments of wMel-infected Aedes aegypti mosquitoes resulted in an 83% reduction in the application of perifocal insecticide spraying, consistent with lower dengue case notifications in wMel-treated areas. These results show that the Wolbachia intervention effect demonstrated previously in a cluster randomised trial was also measurable from routine surveillance data.
Sensitivity of wMel and wAlbB Wolbachia infections in Aedes aegypti Puducherry (Indian) strains to heat stress during larval development
23056K. Gunasekaran, C. Sadanandane, D. Panneer, A. Kumar, M. Rahi, S. Dinesh, B. Vijayakumar, M. Krishnaraja, S. K. Subbarao and P. Jambulingam, Parasites and Vectors, 15:221. 2022-06-21 15:19:54.
BACKGROUND: ICMR-Vector Control Research Centre, Puducherry, India, developed two colonies of Aedes aegypti infected with wMel and wAlbB Wolbacia strains called Ae. aegypti (Pud) lines for dengue control. The sensitivity of wMel and wAlbB strains in Ae. aegypti (Pud) lines to heat stress was studied. METHODS: wMel and wAlbB infected and uninfected Ae. aegypti larvae (first to fourth instars) were reared in the laboratory to adults at 26 °C, 30 °C, 36 °C and 40 °C constant temperatures and also 26-30 °C, 26-36 °C and 26-40 °C diurnal cyclic temperatures. The adults were tested for Wolbachia infection. Experiments were also carried out rearing the larvae under simulated field conditions in summer (April and June) under sunlight using fully open and half open bowls and also under sunlight and natural shade. RESULTS: At 36 °C and 40 °C constant temperatures, complete larval mortality was observed. At 30 °C and 26 °C, no larval mortality occurred, but Wolbachia density was relatively low in wMel infected males compared to control (maintained at 26 ± 1 °C). At diurnal cyclic temperature of 26-40 °C, Wolbachia density was reduced in males of both the (Pud) lines, but not in females. At 26-36 °C, reduction in Wolbachia density was observed in wMel males but not in wAlbB males. At 26-30 °C, no significant reduction in Wolbachia density was observed with wMel and wAlbB strains. In simulated field conditions (April), under sunlight, the daytime water temperature reached a maximum of 35.7 °C in both full and half open bowls. No larval mortality occurred. Wolbachia frequency and density was reduced in wMel-infected Ae. aegypti (Pud) males from both type of bowls and in females from full open bowls, and in wAlbB males from half open bowls. In June, rearing of larvae under sunlight, the first-instar larvae experienced a maximum daytime water temperature of > 38 °C that caused complete mortality. No larval mortality was observed in bowls kept under shade (< 32 °C). CONCLUSIONS: Exposure of larvae to higher rearing temperatures in the laboratory and simulated-field conditions reduced the densities of wMel and wAlbB strains particularly in males, but the impact was more pronounced for wMel strain. The actual effect of heat stress on the stability of these two Wolbachia strains needs to be tested under natural field conditions.
Elimination of a closed population of the yellow fever mosquito, Aedes aegypti, through releases of self-limiting male mosquitoes
22519P. B. Patil, S. K. Dasgupta, K. Gorman, A. Pickl-Herk, M. Puinean, A. McKemey, B. Char, U. B. Zehr and S. R. Barwale, PLOS Neglected Tropical Diseases, 16:e0010315. 2022-05-16 09:19:04.
Author summary Aedes aegypti L. species is the primary vector responsible for transmission of the dengue virus worldwide including chikungunya, yellow fever and Zika virus. The experiment presented in the manuscript represents a study undertaken to demonstrate suppression of the wild type Ae. aegypti population in large outdoor field cages with natural exposure to the environment (physically-contained field cage facility) by sustained releases of male adults of OX513A Ae. aegypti strain. This investigation is a phase-2 contained study as per the World Health Organization guidelines for evaluation of genetically modified organisms and was recommended by the Indian regulatory board. This experiment demonstrates suppression of wild type Ae. aegypti population by sustained releases of OX513A male adults in a contained facility. The prospect of the project is to demonstrate and implement the technology for controlling/suppression of the Ae. aegypti vector in the open field environment.
Safety Assessment of Novel Genetic Technologies for Vector Control: National and International Perspectives
19961V. Ahuja, Genetically Modified and other Innovative Vector Control Technologies, 2021-12-21 11:15:26.
Novel genetic technologies provide an alternative approach for control of vectors particularly those carrying deadly pathogens. Genetic control technologies aim to either suppress target populations or modify the vector by introducing a heritable factor that reduces or blocks their ability to transmit the diseases. These technologies are thus referred to as population suppression or population modification approaches. Both these approaches offer significant advantages for vector control; however, there are associated biosafety concerns related to possible ecosystem interactions. Therefore, extensive testing on a case-by-case basis is required before these can be used as a public health intervention. This paper provides details of the international initiatives towards development of guidelines and status of regulations in India.
Genetic Control in Historical Perspective: The Legacy of India’s Genetic Control of Mosquitoes Unit
19652R. Wilbanks, Hastings Center Report, 51:S11-S18. 2021-12-14 18:54:15.
Abstract In the early 1970s, a World Health Organization-initiated and United States-funded project released lab-reared mosquitoes outside New Delhi in the first large-scale field trials of the genetic control of mosquitoes. Despite partnering with the Indian Council of Medical Research and investing significantly in outreach to local communities at the release sites, the project was embroiled in controversy and became an object of vehement debate within the Indian parliament and diplomatic contretemps between the United States and India. This early episode of genetic control research demonstrates how a scientific collaboration was entangled in geopolitics and shaped by the legacy of colonialism. This historical case study has implications for public deliberation in the present, pointing to the challenges of shared decision-making in the context of structural inequality, the way that a backdrop of military interest in a technology can impede trust, and the long-term consequences of projects that foster mistrust.
Towards Integrated Management of Dengue in Mumbai
19735P. N. Paradkar, P. R. Sahasrabudhe, M. Ghag Sawant, S. Mukherjee and K. R. Blasdell, Viruses, 13. 2021-12-04 13:10:23.
With increasing urbanisation, the dengue disease burden is on the rise in India, especially in large cities such as Mumbai. Current dengue surveillance in Mumbai includes municipal corporation carrying out specific activities to reduce mosquito breeding sites and the use of insecticides to suppress the adult mosquito populations. Clinical cases remain either underreported or misreported due to the restriction to government clinics, missing the large private health care sector. There is a need for an integrated approach to manage dengue outbreaks in Mumbai. There are various novel strategies available for use that can be utilised to improve disease detection, mosquito surveillance, and control of mosquito-borne diseases. These novel technologies are discussed in this manuscript. Given the complex ecosystem of mosquito-borne diseases in Mumbai, integrating data obtained from these technologies would support the ongoing mosquito control measures in Mumbai.
Manipulated Mosquitoes Cut Dengue by 77%
17513T. Hayes, Healthcare Packaging, 2021-06-22 14:34:21.
Dengue, a mosquito-borne viral disease, wasn’t that common 50 years ago. In fact, only nine countries had severe outbreaks. But since then, it’s been on a steady incline to the point that there are now 400 million infections a year that contribute to 22,000 deaths. Thankfully, we have the World Mosquito Programme, a group that’s fighting the tropical mosquito disease head-on with genetically modified mosquitoes. The insects are infected with Wolbachia, a bacteria that inhibits viruses’ ability to live inside the insects, and also controls reproduction so that offspring are also infected with the bacteria. The result is a new population of insects that can’t transmit viruses like dengue, yellow fever and Zika. The study in Indonesia included 8,000 people, and concluded with protective efficacy of 77.1%.
Dengue fever: Upstaged but not outmatched by COVID-19
17490C. E. Baclig, INQUIRER.NET, 2021-06-17 15:17:30.
Science has made gains in the war on dengue and other diseases that mosquitoes carry, like malaria.One of these is the World Mosquito Program (WMP), a non-profit initiative that aims to protect the global community from mosquito-borne viral diseases, by deploying a natural bacteria, called Wolbachia. On its website, WMP said its scientists had discovered that Aedis aegypti mosquitoes carry Wolbachia, a bacteria which competes with viruses like dengue, zika, chikungunya, and the virus that causes yellow fever. Wolbachia, WMP said, was found to make it difficult for viruses to reproduce inside mosquitoes. Mosquitoes carrying Wolbachia, WPS said, “are much less likely to spread viruses from person to person.” Wolbachia is found in 60 percent of insects but is not normally carried by Aedis aegypti mosquitoes. So scientists injected the bacteria into mosquito eggs. Once these hatches and send off grown mosquitoes, they are released to breed with local mosquito populations.
Dengue Infections Can Be Sharply Reduced With Wolbachia Bacteria
17453J. Stone, Medscape, 2021-06-14 17:25:12.
A modestly titled new study released in the New England Journal of Medicine belies the extraordinary 77% protective efficacy reported for preventing dengue infections with Wolbachia-infected Aedes aegypti mosquitoes. A cluster-randomized clinical trial, the AWED ("Applying Wolbachia to Eliminate Dengue") study was conducted in Yogyakarta, Indonesia and led by professors Adi Utarini, MD, PhD, of Gadjah Mada University and Cameron Simmons, PhD, the World Mosquito Program's Oceana director, in partnership with the Tahija Foundation and Monash University.
Making mosquitoes to fight mosquitoes to prevent dengue
17484A. George, Times of India, 2021-06-14 15:04:01.
In 2017, Delhi Chief Minister Arvind Kejriwal tweeted that the national capitl needed to be made mosquito-free. The same year, his Kerala counterpart, Pinaray Vijayan, called a three-day state-wide cleanliness drive as hospitals filled with genue patients.
Dengue Fever Cut Down by 77% With Groundbreaking Bacteria-Armed Mosquitoes
17322M. Davis, The Science Times, 2021-06-10 12:02:22.
Scientists found that dengue fever cases have decreased by 77% in a groundbreaking trial that took place in Yogyakarta City, Indonesia. They used Wolbachia-infected mosquitoes that reduced their ability to spread the dengue fever. The team at the World Mosquito Program said that this could be a solution to dengue fever that is prevalent around the world. Dr. Katie Anders, one of the researchers, described the trial of using Wolbachia-infected mosquitoes in Indonesia as a "naturally miraculous" solution. Wolbachia is a virus-fighting bacteria that has been approved since 2017 by the Environmental Protection Agency (EPA) for use in the United States. Other interventions, like genetically modified mosquitoes, are also used to combat dengue fever and other diseases caused by mosquitoes. According to BBC News, Wolbachia does not harm the mosquito, but it will only be stored in the same parts of the mosquito's body where the dengue virus is kept. It competes for the resources, preventing the dengue virus to replicate, and therefore the mosquito is less likely to cause the infection when it bites. Moreover, Wolbachia bacteria can also manipulate and alter the fertility of their hosts. They make sure that they are passed on to the next generation of mosquitoes, which means they are established and should stick around for a long time to continue their protective abilities against dengue fever.
Mosquito ‘bacteria hack’ nearly eliminates dengue fever and could save millions of lives
17316A. Wilkins, METRO, 2021-06-10 11:50:12.
Mosquitoes infected with a ‘miraculous’ bacteria have been shown to reduce dengue fever cases by 77%, in a groundbreaking new study. Scientists released mosquitoes infected with ‘Wolbachia’ bacteria into the Indonesian city of Yogyakarta – but only in certain zones. In the zones where the modified mosquitoes had been released, cases of dengue fell by 77% and hospitalisations dropped by 86%. The results of the study, carried out by the World Mosquito Programme (WMP), were ‘better than we could have hoped for’, according to researcher Dr. Katie Anders. Cases of dengue fever, a virus that can cause muscle and bone pain, and death, have risen rapidly in the past decades – there are an estimated 400 million cases a year. The Wolbachia bacteria used in the trial were chosen because it hides in the same parts of a mosquito’s body that dengue virus hides in. A bacteria that is benign to humans, the Wolbachia then competes for resources with the dengue virus, which makes it less likely for the mosquito to cause a dengue infection when it bites a human.
‘Miraculous’ mosquito hack cuts dengue by 77%
17311J. Gallagher, BBC, 2021-06-10 11:38:57.
Dengue fever cases have been cut by 77% in a "groundbreaking" trial that manipulates the mosquitoes that spread it, say scientists. They used mosquitoes infected with "miraculous" bacteria that reduce the insect's ability to spread dengue. The trial took place in Yogyakarta city, Indonesia, and is being expanded in the hope of eradicating the virus. The World Mosquito Programme team says it could be a solution to a virus that has gone around the world. Few people had heard of dengue 50 years ago, but it has been a relentless slow-burning pandemic and cases have increased dramatically. In 1970, only nine countries had faced severe dengue outbreaks, now there are up to 400 million infections a year. Dengue is commonly known as "break-bone fever" because it causes severe pain in muscles and bones and explosive outbreaks can overwhelm hospitals.
Modified mosquitoes reduce dengue cases by 77% in Indonesia experiment
17309M. Fox, CNN, 2021-06-10 11:32:59.
An experiment to infect mosquitoes with bacteria that stop them from transmitting viruses appears to have helped reduced the spread of deadly dengue virus in Indonesia, researchers reported Wednesday. The modified mosquitoes thrived for three years, and cases of dengue were reduced by 77% in areas where they were introduced, the researchers reported in the New England Journal of Medicine. The mosquitoes are infected with bacteria called Wolbachia, which not only interfere with the ability of viruses to live in the bodies of the insects, but which also control reproduction so that the mosquitoes only have Wolbachia-infected offspring. The result is a growing population of insects that don't pass on viruses such as dengue, yellow fever and Zika. The study involved more than 8,000 people, about half of whom lived in areas where the modified Aedes aegypti mosquitoes had been living and breeding.
Efficacy of Wolbachia-Infected Mosquito Deployments for the Control of Dengue
17300A. Utarini, C. Indriani, R. A. Ahmad, W. Tantowijoyo, E. Arguni, M. R. Ansari, E. Supriyati, D. S. Wardana, Y. Meitika, I. Ernesia, I. Nurhayati, E. Prabowo, B. Andari, B. R. Green, L. Hodgson, Z. Cutcher, E. Rancès, P. A. Ryan, S. L. O’Neill, S. M. Dufau, New England Journal of Medicine, 384:2177-2186. 2021-06-10 11:05:41.
BACKGROUND Aedes aegypti mosquitoes infected with the wMel strain of Wolbachia pipientis are less susceptible than wild-type A. aegypti to dengue virus infection. METHODS We conducted a cluster-randomized trial involving releases of wMel-infected A. aegypti mosquitoes for the control of dengue in Yogyakarta, Indonesia. We randomly assigned 12 geographic clusters to receive deployments of wMel-infected A. aegypti (intervention clusters) and 12 clusters to receive no deployments (control clusters). All clusters practiced local mosquito-control measures as usual. A test-negative design was used to assess the efficacy of the intervention. Patients with acute undifferentiated fever who presented to local primary care clinics and were 3 to 45 years of age were recruited. Laboratory testing was used to identify participants who had virologically confirmed dengue (VCD) and those who were test-negative controls. The primary end point was symptomatic VCD of any severity caused by any dengue virus serotype. RESULTS After successful introgression of wMel into the intervention clusters, 8144 participants were enrolled; 3721 lived in intervention clusters, and 4423 lived in control clusters. In the intention-to-treat analysis, VCD occurred in 67 of 2905 participants (2.3%) in the intervention clusters and in 318 of 3401 (9.4%) in the control clusters (aggregate odds ratio for VCD, 0.23; 95% confidence interval [CI], 0.15 to 0.35; P=0.004). The protective efficacy of the intervention was 77.1% (95% CI, 65.3 to 84.9) and was similar against the four dengue virus serotypes. The incidence of hospitalization for VCD was lower among participants who lived in intervention clusters (13 of 2905 participants [0.4%]) than among those who lived in control clusters (102 of 3401 [3.0%]) (protective efficacy, 86.2%; 95% CI, 66.2 to 94.3).
Mosquitoes armed with virus-fighting bacteria sharply curb dengue infections, hospitalizations
17319K. Servick, Science, 2021-06-09 11:55:26.
A strategy for fighting dengue fever with bacteria-armed mosquitoes has passed its most rigorous test yet: a large, randomized, controlled trial. Researchers reported today dramatic reductions in rates of dengue infection and hospitalization in areas of an Indonesian city where the disease-fighting mosquitoes were released. The team expects the World Health Organization (WHO) to formally recommend the approach for broader use. The findings are a “breakthrough” that brings the approach “much closer to … being an official strategy to control dengue,” says Ewa Chrostek, an infection biologist at the University of Liverpool who was not involved with the work. WHO estimates there are 100 million to 400 million infections per year with dengue, which can cause high fever and severe joint pain. The bacterium Wolbachia pipientis naturally inhabits many insects, though not Aedes aegypti mosquitoes, the main transmitter of dengue virus. In A. aegypti cells, the bacterium can block viruses, including dengue, from replicating, making the insects less likely to spread disease when they bite humans. That has made the microbe a promising strategy for fighting dengue. In tropical regions, where mosquito-borne viruses are common, other strategies such as insecticides have failed to fully control the disease.
Study demonstrates ‘exciting potential’ of Wolbachia-infected mosquitoes to control dengue
17313G. Gallagher, Healio, 2021-06-09 11:43:08.
The release of Wolbachia-infected mosquitoes led to a 77% reduction in the incidence of symptomatic dengue in an Indonesian city, according to researchers, who said the same approach could be used to fight other mosquito-borne diseases. The study tested a strain of Wolbachia pipientis called wMel that makes Aedes aegypti mosquitoes less susceptible to dengue virus infection. Wolbachia pipientis occurs naturally in many insects but not A. aegypti, the primary vector of dengue, according to Adi Utarini, PhD, MPH, MSc, and colleagues from the nonprofit World Mosquito Program, which has been releasing Wolbachia-infected mosquitoes in the wild since 2011. A study in Indonesia demonstrated the potential of a natural intervention to significantly reduce the incidence of dengue, the world’s most prevalent mosquito-borne disease. “Wolbachia facilitates its own population introgression by manipulating reproductive outcomes between wild-type and Wolbachia-infected mosquitoes: the only viable mating outcomes are those in which the progeny are infected with Wolbachia,” they wrote in the new report, which was published Wednesday in The New England Journal of Medicine.
Transgenic mosquito resistant to multiple serotypes of the dengue virus
34972Department of Chemistry, Faculty of Science, University of Colombo in collaboration with the Molecular Medicine Unit, Faculty of Medicine, University of Kelaniya, University of Colombo, 2021-04-10 10:39:01.
The dengue virus causes epidemics in more than 100 tropical and sub-tropical countries, where over 2.5 billion people (over 40% of the world’s population) are currently at risk of dengue infections. In recent years, dengue has become the number one vector-borne disease in Sri Lanka. The worst ever dengue virus outbreaks experienced in 2009, 2010, and 2013 transformed dengue into a major health issue in Sri Lanka. There are no medicines or effective vaccines developed for dengue; therefore, mosquito vector control is the most promising option to control dengue virus transmission. The conventional vector control methods used currently have only limited success. In an attempt to find a solution to this problem, the research team lead by Professor Ranil Dassanayake, Department of Chemistry, University of Colombo in collaboration with Professor Nilmini Gunawardene, Molecular Medicine Unit, Faculty of Medicine, University of Kelaniya undertook to develop a dengue virus resistant transgenic Aedes aegypti mosquito (the primary vector of dengue virus transmission) line using an RNA interference (RNAi) based technology, as a component of the Ph.D. research project of Mr. Kalindu Ramyasoma.
The potential cost-effectiveness of controlling dengue in Indonesia using wMel Wolbachia released at scale: a modelling study
14326O. J. Brady, D. D. Kharisma, N. N. Wilastonegoro, K. M. Reilly, E. Hendricx, L. S. Bastos, L. Yakob and D. S. Shepard, medRxiv, 2020.01.11.20017186. 2020-01-16 17:55:32.
Wolbachia releases in high density urban areas is expected to be highly cost-effective and could potentially be the first cost saving intervention for dengue. Sites with strong public health infrastructure, fiscal capacity, and community support should be prioritized.
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