Latest news with #WestNilefever
Time of India
29-07-2025
- Health
- Time of India
West Nile virus: Wisconsin reports first case; Here are the early symptoms to know
Wisconsin has confirmed its first human case of West Nile virus (WNV) for 2025, health officials announced July 28. The infection was identified in a resident of Barron County, while mosquitoes in Milwaukee and Lafayette counties also tested positive for the virus. Though most infected individuals show no symptoms, about 1 in 5 infected by West Nile virus (WNV) develop mild illness, while fewer than 1 in 150 may suffer severe, potentially life-threatening neuroinvasive disease. The virus is primarily transmitted to humans through the bite of infected mosquitoes, which acquire the virus by feeding on infected birds. With no vaccine or targeted antiviral treatment available for humans, prevention and awareness are the primary defenses. While most people don't experience severe symptoms, those over 50 and individuals with weakened immune systems are at higher risk for complications like encephalitis or meningitis. What is West Nile Virus? West Nile virus is a single-stranded RNA virus that causes West Nile fever. It is a member of the family Flaviviridae, from the genus Flavivirus, which also contains the Zika virus, dengue virus, and yellow fever virus. The virus is primarily transmitted by mosquitoes, mostly species of Culex. The virus was initially identified in the West Nile district of Uganda in 1937. It has since spread globally, including Africa, Europe, the Middle East, Asia, Australia, and North America. How does WNV spread? West Nile virus (WNV) is primarily spread to humans through the bite of an infected mosquito. Mosquitoes become infected when they feed on birds that carry the virus. Humans, horses, and other mammals can then contract WNV from the bite of an infected mosquito. Mosquitoes, particularly certain species of Culex mosquitoes, are the main vectors for WNV. They become infected when they bite birds that carry the virus. Birds, especially certain species like crows and jays, are considered amplifying hosts, meaning they can carry high levels of the virus in their blood, making them efficient transmitters to mosquitoes. When an infected female mosquito bites a human or other mammal, it injects saliva, which can contain the virus, into the bloodstream. While mosquito bites are the primary route, WNV can also be transmitted through blood transfusions and organ transplants, as well as from mother to child during pregnancy, delivery, or breastfeeding. There have also been rare cases of transmission in laboratory settings and through oral-fecal routes in alligators and crocodiles. However, West Nile virus is not spread through casual contact with infected individuals or through the air. Moreover, mammals like humans are "dead‑end hosts" because they typically don't carry enough virus in their blood to facilitate further mosquito infection. Peak transmission occurs between July and October, a period marked by warm, humid weather that favors mosquito breeding and bird activity. Early symptoms: What to watch for While most people infected with WNV remain symptom-free (around 80%), about 20% develop West Nile fever, a short-lived, flu-like illness. Key symptoms include: Fever and chills Severe headache Body aches and fatigue Rashes Nausea or vomiting Joint pain These symptoms typically appear 2 to 14 days after infection, though incubation can be longer in immune-compromised individuals. Severe illness: Less common, but a serious health hazard Less than 1% of infected people develop neuroinvasive West Nile disease. This severe form can result in: Meningitis: fever, stiff neck, headache Encephalitis: altered mental state, seizures, tremors Acute flaccid paralysis or coma Muscle weakness or difficulty breathing, possibly requiring hospitalization Who are at risk? Although most people infected with West Nile virus remain asymptomatic (~80%), around 20% experience West Nile fever – flu‑like symptoms including fever, headache, fatigue, and sometimes rash. Less than 1% develop neuroinvasive disease (meningitis or encephalitis), marked by high fever, neck stiffness, confusion, tremors, or paralysis – conditions that can be fatal in about 10% of these cases. Individuals over 60, organ transplant recipients, and those with weakened immune systems or certain chronic (comorbid) conditions like diabetes, high blood pressure, or kidney disease are at higher risk of severe West Nile virus illness. While anyone can be bitten by an infected mosquito, these groups are more likely to experience serious complications if infected. Additionally, people with weakened immune systems, due to conditions like HIV/AIDS, cancer, or undergoing chemotherapy, are more susceptible to severe illness. Individuals who have received organ transplants are at increased risk due to the immunosuppressant medications they take to prevent organ rejection. While not a direct risk factor for acquiring the virus, pregnant women and breastfeeding mothers should be cautious and consult with their doctor if they experience symptoms. Precautions and safety tips To prevent West Nile virus (WNV) infection, the most important precaution is to minimize mosquito bites. This involves using insect repellent, wearing protective clothing, and reducing mosquito breeding sites. Additionally, limiting outdoor activities during peak mosquito hours (dusk and dawn) and ensuring proper screening of windows and doors can help reduce exposure. Department of Public Health and the CDC recommend: Avoid peak mosquito activity: Be cautious at dusk and dawn, when Culex mosquitoes are most active. Use EPA‑registered insect repellents: DEET, picaridin, IR3535, or oil of lemon eucalyptus are recommended. Dress smart: When outdoors, especially during peak mosquito hours, wear long sleeves, long pants, and a hat to cover as much skin as possible. Eliminate standing water weekly: Dump water from flowerpots, gutters, and water bowls, as mosquitoes need only a bottlecap's water to breed. Maintain screens and doors: Install and repair screens on windows and doors to keep mosquitoes out. Use mosquito netting: If you are sleeping outdoors or in an unscreened area, use mosquito netting to prevent bites. Be informed and report: Stay updated on local alerts and report stagnant water or dead birds to county health officials. Be aware of travel risks: If traveling to an area with known WNV activity, take extra precautions and consult with your doctor about necessary preventative measures. Maharashtra reports first case of Zika virus
Daily Mirror
22-05-2025
- Health
- Daily Mirror
Deadly virus found in UK for first time as public sent major warning
Deadly West Nile virus has been detected in UK mosquitoes for the very first time, and cases will "almost certainly" continue to rise over the next few decades, it's been claimed West Nile virus was spotted in the UK for the very first time this week, and an expert has revealed the risk to the wider public will continue to grow. The virus is a disease that's spread in mosquitoes, and is genetically similar to the more common dengue fever and yellow fever. It generally causes a mild fever, but it can spark some serious complications - and even death. Scientists detected West Nile virus in UK mosquitoes that were collected in July 2023, the UK Health Security Agency (UKHSA) revealed yesterday. It's endemic across the world - including in southern Europe and Africa - but it's not been found in British mosquitoes until now. There have, however, been seven cases of travel-associated human patients since the year 2000. Mosquitoes carrying the West Nile virus are likely to become more abdundant in the UK as the climate gets warmer, according to the University of Southampton's Senior Research Fellow in Global Health, Dr Michael Head. When there's most mosquitoes carrying the virus, it naturally raises the risk to the British public, he warned. Dr Head told the Mirror: "The West Nile Virus disease is typically a mild fever, but in around 1 percent of cases can turn into a nasty infection, causing neurological consequences and possibly death. The news of West Nile being present in UK mosquitoes is, to be honest, not that surprising. Mosquito-related viruses, such as dengue and also West Nile, have been present across Europe for decades. Parts of Italy see around 100 West Nile cases per year. "Climate change is supporting the migration of mosquitoes, and with that comes a higher risk of new and emerging infections, such as West Nile Virus. Whilst the threat to the public right now is extremely low, that will almost certainly rise over the next few decades." The UKHSA said the risk to the public was "very low" after the virus was found in mosquitoes. But, the detection would help scientists to prepare for any potential threats. Dr Meera Chand, UKHSA Deputy Director for travel health, zoonoses, emerging infections, respiratory and tuberculosis, said: "While this is the first detection of West Nile Virus in mosquitoes in the UK so far, it is not unexpected as the virus is already widespread in Europe. "The risk to the general public is currently assessed as very low. Vector research of this kind is designed to give us early warning of potential threats so that we can enhance our disease surveillance and control activities and ensure patients receive appropriate testing." Most people with West Nile virus don't show any symptoms at all, according to the World Health Organization. But, in 20% of all patients, it can lead to a condition known as West Nile fever or severe West Nile disease. The most common symptoms of West Nile fever include headaches, body aches, a high fever, vomiting, and a skin rash on the trunk of the body. In more severe patients, it could lead to convulsions, muscle weakness, paralysis, and even coma.
The National
10-02-2025
- Health
- The National
Mosquitoes in UAE becoming resistant to key insecticide
Mosquitoes in the Emirates are becoming resistant to a key insecticide according to researchers at UAE University in Al Ain. The research, published in Nature Scientific Reports, which was funded by UAE University and carried out in collaboration with Abu Dhabi Public Health Centre, suggested that mosquitoes are becoming immune to the effects of the insecticide known as deltamethrin. Mosquitoes transmit a range of deadly diseases, including malaria, which claims about 600,000 lives a year, according to the World Health Organisation. The study, by researchers including postgraduate student Amgd Sayed Ali and co-ordinated by Mohammad Al Deeb, professor of entomology in UAE University's biology department, involved collecting egg clusters and rearing mosquitoes in the laboratory. DNA was extracted and analysed from 174 adult mosquitoes. Prof Al Deeb said he and his co-researchers had been 'curious about whether resistance had developed' given the long-term use of insecticides in the region. 'Our findings aligned with our expectations, as continuous insecticide exposure tends to exert evolutionary pressure on mosquito populations, leading to resistance,' Prof Al Deeb said. 'Resistance means that mosquitoes can no longer be effectively controlled using certain insecticides, leading to increased mosquito populations and a higher risk of disease transmission. 'If resistance spreads across multiple insecticide classes, it can severely limit available control options, making disease outbreaks more difficult to prevent.' Analysing the southern house mosquito, or Culex quinquefasciatus, which does not cause illness in the UAE but in other countries spreads a potentially fatal disease called West Nile fever, the scientists found significant levels of resistance. More than a quarter of mosquitoes grown from eggs collected from coastal sites in Abu Dhabi had two copies of a gene mutation conferring resistance to deltamethrin. At sampling sites near the Omani border, 14.3 per cent of mosquitoes had two copies of the resistance mutation, while at inland sites the figure was 6.3 per cent. Across all locations, 18.4 per cent of the mosquitoes analysed had two copies of the resistance mutation. It is thought to be the first study to analyse insecticide resistance in mosquitoes in the UAE, although Prof Al Deeb and his colleagues have previously detected insecticide resistance in house flies. Prof Al Deeb said he and his co-researchers had been 'curious about whether resistance had developed' given the long-term use of insecticides in the region. 'Our findings aligned with our expectations, as continuous insecticide exposure tends to exert evolutionary pressure on mosquito populations, leading to resistance,' Prof Al Deeb said. 'Resistance means that mosquitoes can no longer be effectively controlled using certain insecticides, leading to increased mosquito populations and a higher risk of disease transmission. 'If resistance spreads across multiple insecticide classes, it can severely limit available control options, making disease outbreaks more difficult to prevent.' Resistance evolves because when an insecticide is applied, people with alleles (different versions of a gene) that confer resistance are more likely than others to survive and reproduce. This causes resistance alleles to become more common over time and can render insecticides ineffective. In the case of insecticide resistance in the southern house mosquito, the resistance mutation alters a nerve cell membrane channel through which sodium passes. In susceptible mosquitoes, the insecticide causes the sodium channel to remain open, paralysing and killing the insect. Elsewhere in the world, the consequences of mosquitoes becoming resistant to insecticides have been significant. 'It's one of the major concerns about malaria rates,' said Prof Martin Donnelly, of the Liverpool School of Tropical Medicine in the UK, who researches genetic factors that affect resistance. 'Since about 2015 the gains we've seen in sub-Saharan Africa have stalled. It's largely as a result of drug resistance and insecticide resistance.' Prof Al Deeb said that to effectively combat insecticide resistance in the UAE, long-term monitoring programmes should be established. 'Our study serves as the first step toward developing resistance management strategies in the country,' he said. Resistance can be reduced by rotating which insecticides are used, because once any given type is no longer applied, mosquito populations are likely to become susceptible again over time. The best approach is, Prof Al Deeb said, integrated pest management, which combines various control methods. These include introducing mosquito predators such as fish that eat insect larvae, the use of mosquito traps, the modification of habitats so there are fewer breeding sites, and improvements in sanitation. While the southern house mosquito is not believed to transmit diseases in the UAE, this situation may change, especially as climate change is altering where vector-borne diseases are found. 'Since environmental changes and mosquito behaviour can shift over time, ongoing surveillance is crucial to ensure this species does not become a public health concern in the UAE,' Prof Al Deeb said. His research group is keen to look at resistance trends over time, resistance in other mosquito species and alternative control strategies. 'If funding becomes available, we plan to conduct further research to develop evidence-based mosquito management policies for the UAE,' Prof Al Deeb said.
