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Washington Post
3 days ago
- Health
- Washington Post
We finally may be able to rid the world of mosquitoes. But should we?
They buzz, they bite and they cause some of the deadliest diseases known to humanity. Mosquitos are perhaps the planet's most universally reviled animals. If we could zap them off the face of the Earth, should we? The question is no longer hypothetical. In recent years, scientists have devised powerful genetic tools that may be able to eradicate mosquitoes and other pests once and for all. Now, some doctors and scientists say it is time to take the extraordinary step of unleashing gene editing to suppress mosquitoes and avoid human suffering from malaria, dengue, West Nile virus and other serious diseases. 'There are so many lives at stake with malaria that we want to make sure that this technology could be used in the near future,' said Alekos Simoni, a molecular biologist with Target Malaria, a project aiming to target vector mosquitos in sub-Saharan Africa. Yet the development of this technology also raises a profound ethical question: When, if ever, is it okay to intentionally drive a species out of existence. Even the famed naturalist E.O. Wilson once said: 'I would gladly throw the switch and be the executioner myself' for malaria-carrying mosquitos. But some researchers and ethicists warn it may be too dangerous to tinker with the underpinnings of life itself. Even irritating, itty-bitty mosquitoes, they say, may have enough inherent value to keep around. Target Malaria is one of the most ambitious mosquito suppression efforts in the works. Simoni and his colleagues are seeking to diminish populations of mosquitoes in the Anopheles gambiae complex that are responsible for spreading that deadly disease. In their labs, the scientists have introduced a gene mutation that causes female mosquito offspring to be born without functional ovaries, rendering them infertile. Male mosquito offspring can carry the gene but remain physically unaffected. The concept is that when female mosquitoes inherit the gene from both their mother and father, they will go on to die without producing offspring. Meanwhile, when males and females carrying just one copy of the gene mate with wild mosquitoes, they will spread the gene further until no fertile females are left — and the population crashes. Simoni said he hopes the project can move beyond the lab and deploy some of the genetically modified mosquitoes in their natural habitats within the next five years. 'We believe that this technology can really be transformative,' he said. At the heart of Target Malaria's work is a powerful genetic tool called a gene drive. Under the normal rules of inheritance, a parent has a 50-50 chance of passing a particular gene on to an offspring. But by adding special genetic machinery — dubbed a gene drive — to segments of DNA, scientists can rig the coin flip and ensure a gene is included in an animal's eggs and sperm, nearly guaranteeing it will be passed along. Over successive generations, gene drives can cause a trait to spread across an entire species' population, even if that gene doesn't benefit the organism. In that way, gene drives do something remarkable: They allow humans to overwrite Charles Darwin's rules for natural selection, which normally prods populations of plants and animals to adapt to their environment over time. 'Technology is presenting new options to us,' said Christopher Preston, a University of Montana environmental philosopher. 'We might've been able to make a species go extinct 150 years ago by harpooning it too much or shooting it out of the sky. But today, we have different options, and extinction could be completed or could be started in a lab.' When so many wildlife conservationists are trying to save plants and animals from disappearing, the mosquito is one of the few creatures that people argue is actually worthy of extinction. Forget about tigers or bears — it's the tiny mosquito that is the deadliest animal on Earth. The human misery caused by malaria is undeniable. Nearly 600,000 people died of the disease in 2023, according to the World Health Organization, with the majority of cases in Africa. On the continent, the death toll is akin to 'crashing two Boeing 747s into Kilimanjaro' every day, said Paul Ndebele, a bioethicist at George Washington University. For gene-drive advocates, making the case for releasing genetically modified mosquitoes in nations such as Burkina Faso or Uganda is straightforward. 'This is not a difficult audience because these are people that are living in an area where children are dying,' said Krystal Birungi, an entomologist for Target Malaria in Uganda, though she added that she sometimes has to fight misinformation, such as the false idea that bites from genetically modified mosquitoes can make people sterile. But recently, the Hastings Center for Bioethics, a research institute in New York, and Arizona State University brought together a group of bioethicists to discuss the potential pitfalls of intentionally trying to drive a species to extinction. In a policy paper published in the journal Science last month, the group concluded 'deliberate full extinction might occasionally be acceptable, but only extremely rarely.' A compelling candidate for total eradication, according to the bioethicists, is the New World screwworm. This parasitic fly, which lays eggs in wounds and eats the flesh of both humans and livestock, appears to play little role in ecosystems. Infections are difficult to treat and can lead to slow and painful deaths. Yet it may be too risky, they argue, to use gene drives on invasive rodents on remote Pacific islands where they decimate native birds, given the nonzero chance of a gene-edited rat or mouse jumping ship to the mainland and spreading across a continent. 'Even at a microbial level, it became plain in our conversations, we are not in favor of remaking the world to suit human desires,' said Gregory Kaebnick, a senior research scholar at the institute. It's unclear how important malaria-carrying mosquitos are to broader ecosystems. Little research has been done to figure out whether frogs or other animals that eat the insects would be able to find their meals elsewhere. 'The eradication of the mosquito through a genetic technology would have the potential to create global eradication in a way that just felt a little risky,' said Preston, who contributed with Ndebele to the discussion published in Science. Instead, the authors said, geneticists should be able to use gene-editing, vaccines and other tools to target not the mosquito itself, but the single-celled Plasmodium parasite that is responsible for malaria. That invisible microorganism — which a mosquito transfers from its saliva to a person's blood when it bites — is the real culprit. 'You can get rid of malaria without actually getting rid of the mosquito,' Kaebnick said. He added that at a time when the Trump administration talks cavalierly about animals going extinct, intentional extinction should be an option for only 'particularly horrific species.' But Ndebele, who is from Zimbabwe, noted that most of the people opposed to the elimination of the mosquitoes 'are not based in Africa.' Ndebele has intimate experience with malaria; he once had to rush his sick son to a hospital after the disease manifested as a hallucinatory episode. 'We're just in panic mode,' he recalled. 'You can just imagine — we're not sure what's happening with this young guy.' Still, Ndebele and his colleagues expressed caution about using gene-drive technology. Even if people were to agree to rid the globe of every mosquito — not just Anopheles gambiae, but ones that transmit other diseases or merely bite and irritate — it would be a 'herculean undertaking,' according to Kaebnick. There are more than 3,500 known species, each potentially requiring its own specially designed gene drive. And there is no guarantee a gene drive would wipe out a population as intended. Simoni, the gene-drive researcher, agreed there are limits to what the technology can do. His team's modeling suggests it would suppress malaria-carrying mosquitoes only locally without outright eliminating them. Mosquitoes have been 'around for hundreds of millions of years,' he said. 'It's a very difficult species to eliminate.'
Bloomberg
21-05-2025
- Health
- Bloomberg
UK Finds West Nile Virus in Local Mosquitoes for First Time
The UK has detected fragments of West Nile virus in mosquitoes for the first time as the disease spreads to more temperate regions. The risk to the general public is very low and there's no evidence of the virus circulating in birds — its original host — or mosquitoes in the country at the moment, the UK Health Security Agency said Wednesday.
Irish Times
20-05-2025
- Health
- Irish Times
More than 120 countries back treaty to share vaccines in pandemics
World Health Organisation countries have finally approved a treaty to combat future pandemics, boosting international disease control efforts that are under growing pressure from funding cuts and political rows. Member states of the 194-nation global health body conditionally agreed on Tuesday to ensure countries that shared virus samples would receive disease tests, medicines and vaccines, after many poorer nations suffered shortages during the Covid-19 crisis. The measures to tackle the resource inequities that blighted the global response to Covid-19 come after rich nations have slashed aid budgets and the US has announced it will leave the WHO. The new pandemic treaty will go for ratification by participant countries once an annex on the long-contentious topic of detecting and sharing data on emerging pathogens is agreed. Tedros Adhanom Ghebreyesus, WHO director general, hailed the treaty as a 'historic' accord that would make the world safer. 'The agreement is a victory for public health, science and multilateral action,' he said. 'It will ensure we, collectively, can better protect the world from future pandemic threats. It is also a recognition by the international community that our citizens, societies and economies must not be left vulnerable to again suffer losses like those endured during Covid-19.' The pact was backed in Geneva by the WHO's annual World Health Assembly of member states after winning support in a committee vote late on Monday. More than 120 countries supported it with none against, although 11 abstained, including Poland, Israel, Italy, Russia, Slovakia and Iran. READ MORE The agreement, originally meant to be finalised a year ago, aims to improve international mechanisms for pandemic prevention, preparedness and response. The deal sets out a provisional mechanism in which participating drugs companies would aim to make 20 per cent of their real-time production of pandemic vaccines, medicines and diagnostic tests available to the WHO. These would be distributed according to public health risks and needs, with a particular focus on developing countries. This mechanism – known as the Pathogen Access and Benefit Sharing system (Pabs) – will now go to an international working group to be drafted and negotiated for consideration at next year's World Health Assembly. An agreement on Pabs has been delayed by disagreements over proposals for pharmaceutical companies to fund the monitoring of new pathogens, which should in turn speed up efforts at vaccine development. The pharmaceutical industry lobby group said the treaty was just a 'starting point', and its success would depend on how it was implemented. The WHO international working group will also work on setting up a financial mechanism and global supply and logistics network to support the treaty's efforts. When Covid-19 vaccines were rolled out starting at the end of 2020, many poorer countries had only meagre supplies after richer nations bought up most of the doses. The pandemic accord has drawn criticism from conservatives in the US and other countries. They have attacked it as a threat to government sovereignty on health policy and intellectual property protection, although the pact's supporters say it is neither. The accord says that it does not provide the WHO with any authority to dictate government policies in areas such as travel restrictions, vaccination mandates or lockdowns. International health experts welcomed the pandemic accord, but some queried whether all countries would comply – and, if not, what mechanisms would force them to do so. − Copyright The Financial Times Limited 2025
Medscape
19-05-2025
- Health
- Medscape
Why Is Oropouche Spreading so Fast?
Robert D. Glatter, MD Oropouche virus (OROV) cases surged significantly in 2024 and early 2025, with almost 20,000 confirmed infections reported across Latin America and the Caribbean, including four deaths. The highest burden was observed in Brazil, followed by Peru and Cuba. This sudden spike has captured the attention of public health officials. What set the stage for its resurgence and rapid geographic spread? Having followed arboviral outbreaks closely over the past few years, this sudden rise is concerning, not just for its scale but for its silence. Like dengue, Zika, and chikungunya, OROV is transmitted through the bite of infected arthropods, navigating a complex web of vectors, vertebrate hosts, and increasingly permissive environments. What makes OROV especially insidious is its dual-cycle transmission: an urban cycle dominated by Culicoides paraensis midges and a sylvatic cycle involving mosquitoes like Aedes serratus and Culex quinquefasciatus . First identified in Trinidad and Tobago in the 1950s and isolated in Brazil in 1960, OROV has since spread across the Amazon and other parts of Central and South America, with outbreaks driven by environmental changes, deforestation, urbanization, and human mobility. From a clinical standpoint, OROV presents much like dengue or chikungunya: fever, headache, muscle pain, and rash. But around 40% of those infected show no symptoms at all, which further complicates surveillance. And while most symptomatic cases resolve within 2 weeks, severe neurological complications, such as meningitis and encephalitis, are rare but possible. That alone should keep public health officials alert. A Developing Story In February 2024, Rio de Janeiro confirmed its first case of Oropouche fever in a man who had returned from the Brazilian state of Amazonas, signaling the virus's expansion beyond its traditional hotspots in Amazonas, Acre, and Rondônia. Simultaneously, Brazil faced a severe dengue epidemic, surpassing one million cases in the first 2 months of 2024. The overlapping symptoms between Oropouche fever and other arboviruses suggest a significant underdiagnosis of Oropouche cases, creating a major challenge for the health system. In July 2024, Brazil reported the world's first deaths from OROV, involving two previously healthy women from the state of Bahia, highlighting the severity of the disease and the urgent need for enhanced surveillance and public health responses. In 2024, the highest burden of OROV infections was observed in Brazil (13,785 cases and all four deaths), Peru (1263), and Cuba (626). In early 2025 (epidemiological weeks 1-4), an additional 3765 confirmed cases were reported, predominantly in Brazil (3678), with smaller numbers in Panama (79), Cuba (4), Peru (2), and isolated imported cases in Canada, the United States, and Guyana. Since the last update in December 2024, 6990 new cases have been registered. Notably, Brazil also reported cases of possible vertical transmission in 2024, with five confirmed outcomes (four fetal deaths and one congenital anomaly), and several other fetal and neonatal outcomes remain under investigation. In the United States, OROV cases surged in 2024, with 108 imported cases , predominantly in Florida. However, as of early 2025, only 14 additional cases were reported, reflecting either a decline in travel-related exposure or potential underdiagnosis. Imported cases were also detected in Canada (2 cases) and several European countries (30 cases), all linked to travel from endemic regions. According to the US Centers for Disease Control and Prevention (CDC), cases in the country have followed a travel-related pattern. While the absence of local transmission is reassuring, the presence of competent vectors such as C paraensis in several southern US states raises concerns about the potential for future outbreaks. The CDC emphasizes the importance of early detection, clinical awareness, and vector surveillance to prevent local establishment of the virus. Why Now? Julia Sader Neves Ferreira, MD The rapid expansion of OROV is attributed to multiple interconnected factors. Climate change has played a significant role, as rising global temperatures, increased rainfall, and shifting humidity levels have created optimal breeding conditions for midges and mosquitoes, the primary vectors of the virus. Warmer climates accelerate the lifecycle of these arthropods, prolonging their activity and expanding their geographical range, which has contributed to the virus's emergence in non-endemic regions such as the Caribbean and southern United States. Deforestation and urbanization have further intensified the spread of OROV. The destruction of tropical forests in Brazil, Colombia, and Peru has brought human populations into closer contact with sylvatic virus reservoirs, including non-human primates and sloths, which serve as intermediate hosts. Simultaneously, unplanned urban expansion in Latin America has led to an increase in artificial water reservoirs, providing ideal breeding grounds for disease-carrying vectors. As rural populations migrate to urban centers, the risk of sustained human-to-human transmission in densely populated areas continues to rise. Another key factor is the increase in human mobility and globalization, which has significantly facilitated the spread of OROV beyond its historically endemic areas. Imported cases in the United States, Canada, and Europe demonstrate how infected travelers inadvertently carry the virus to non-endemic regions, increasing the likelihood of localized outbreaks. Furthermore, recent studies indicate that OROV RNA can persist in semen for up to 58 days, raising concerns over potential sexual transmission. While no confirmed cases of sexually transmitted OROV have been documented, the persistence of viral RNA in bodily fluids mirrors patterns seen in other arboviruses, such as Zika. This suggests that sexual transmission could play a role in maintaining OROV circulation outside vector-driven outbreaks, particularly in urban settings where direct human-to-human transmission may become a contributing factor. As OROV continues its rapid spread, the likelihood of its establishment in new regions, sustained transmission, and potential adaptation to different vectors poses an increasing concern. The overlapping impact of climate change, deforestation, urbanization, and human migration has accelerated the virus's expansion at an unprecedented rate. With the first confirmed deaths reported in 2024 and the continued increase in cases in 2025, urgent global interventions are required, including enhanced vector control strategies, improved diagnostic capabilities, and further research into sexual transmission and vaccine development. Is Vaccination a Possibility? Researchers are employing advanced techniques to identify viral components that can stimulate the immune system, paving the way for potential vaccines. Several approaches are under investigation, including live attenuated vaccines, chemically inactivated vaccines, DNA-based vaccines, and protein-subunit vaccines. A promising candidate is a live attenuated vaccine derived from the weakened OROV strain, BeAn19991, which has shown positive results in animal studies and demonstrated safety and efficacy in a phase I trial with healthy volunteers, eliciting a strong immune response without serious side effects. Another innovative approach involves a vaccine utilizing a modified vesicular stomatitis virus to deliver OROV proteins. This vaccine has protected mice from the virus, indicating potential for human application. Advancements in reverse genetics are also anticipated to significantly aid vaccine development by enabling scientists to modify the virus's genetic material to create vaccines that elicit robust and targeted immune responses. Researchers are experimenting with various genetic modifications to attenuate the virus while maintaining its effectiveness as a vaccine. Insights from vaccine development for related viruses, such as Schmallenberg virus (SBV), Aino virus, and Akabane virus, are informing OROV vaccine research. These veterinary vaccines have successfully reduced or prevented infections in animals. For instance, a bivalent vaccine combining proteins from both SBV and Akabane virus has conferred protection in cattle. Additionally, DNA-based vaccines for these viruses have safeguarded mice by preventing weight loss and reducing viral levels in the blood. These cross-species insights offer hope — but human application is still a work in progress. Developing a vaccine for OROV presents challenges due to the virus's genetic diversity and the necessity for broad protection against multiple strains. Although no licensed vaccines for OROV currently exist, ongoing research and clinical trials provide a promising foundation for the future prevention of Oropouche fever. With no licensed vaccine available yet, we're left with traditional control measures: vector surveillance, environmental interventions, and public awareness. Governments must invest not just in emergency response, but in research, innovation, and early detection systems. Community education and personal protection — window screens, repellents, long sleeves — remain frontline defenses, especially for those living in or traveling to high-risk areas. WHO Global Initiative for Arboviral Diseases In response to the escalating threat of arboviral diseases, the World Health Organization (WHO) launched the Global Arbovirus Initiative on March 31, 2022. This initiative aims to monitor and control diseases caused by arthropod-borne viruses, such as dengue, Zika, Chikungunya, and yellow fever, by implementing an integrated approach across various sectors and disciplines. The initiative focuses on six key pillars: monitoring risk and anticipating epidemics, reducing local epidemic risks, strengthening vector control, preparing for pandemics, enhancing innovation in diagnostics and treatments, and building a coalition of partners. Building upon this foundation, the WHO introduced the Global Strategic Preparedness, Readiness, and Response Plan in October 2024 to specifically target dengue and other Aedes-borne arboviruses. This plan outlines priority actions for countries to control transmission, emphasizing areas such as disease surveillance, laboratory activities, vector control, community engagement, clinical management, and research and development. The plan is designed to be implemented over 1 year, concluding in September 2025, and requires an estimated US $55 million to support health preparedness and response efforts. This plan aligns with existing strategies, including the Global Vector Control Response 2017-2030 and the Global Arbovirus Initiative. Factors such as unplanned urbanization, climate change, and increased international travel have contributed to the rapid geographical spread of these diseases, making a unified and comprehensive approach essential. Through these concerted efforts, the WHO aims to reduce the burden of arboviral diseases worldwide by enhancing surveillance, improving vector control, promoting research and innovation, and strengthening partnerships across sectors and regions. "The next pandemic could very likely be due to a new arbovirus, and we already have some signals that the risk is increasing," said Sylvie Briand, WHO director of pandemic and epidemic diseases. "Since 2016, more than 89 countries have faced epidemics due to the Zika virus. Given human mobility and urbanization, the risk of amplifying localized arbovirus outbreaks is real."
