Latest news with #Pteropus
Indian Express
a day ago
- Health
- Indian Express
Lyssavirus is rare, but deadly — what should you do if bat bites you?
By Vinod Balasubramaniam A man in his 50s has died from lyssavirus in New South Wales after being bitten by a bat several months ago. This is Australia's fourth human case of bat lyssavirus and the first confirmed case in NSW since the virus was first identified in 1996 in a black flying fox in Queensland. So what is lyssavirus? And how can you protect yourself if you come into contact with a bat? Australian bat lyssavirus belongs to the Rhabdoviridae family, the same group of viruses that causes rabies. It primarily infects bats. Active monitoring suggests fewer than 1 per cent of healthy bats carry the virus, though prevalence rises to 5–10 per cent in sick or injured bats. In bats, the virus often causes no obvious symptoms, though some show neurological signs such as disorientation, aggression, muscle spasms and paralysis. Some will die. The virus has been confirmed in all four mainland flying fox species (Pteropus alecto, P. poliocephalus, P. scapulatus and P. conspicillatus) as well as the yellow-bellied sheathtail bat (Saccolaimus flaviventris), a species of microbat. However, serological evidence – where scientists test for antibodies in bats' blood – suggests other microbats could be susceptible too. So we should be cautious with all Australian bat species when it comes to lyssavirus. Unlike rabies, which causes roughly 59,000 human deaths annually, predominantly in Africa and Asia, human infection with bat lyssavirus is extremely rare. Australian bat lyssavirus, as the name suggests, is unique to Australia. But other bat lyssaviruses, such as European bat lyssavirus, have similarly caused rare human infections. Human infection with bat lyssavirus occurs through direct contact with infected bat saliva via bites, scratches or open skin. It can also occur if our mucous membranes (eyes, nose, mouth) are exposed to bat saliva. There's no risk associated with bat faeces, urine, blood, or casual proximity to roosts. If someone has been exposed, there's an incubation period which can range from weeks to more than two years. During this time the virus slowly moves through the body's nerves to the brain, staying hidden and symptom-free. Treating the virus during the incubation period can prevent the illness. But if it's not treated, symptoms are serious and it's invariably fatal. The nature of the illness in humans mirrors rabies, beginning with flu-like symptoms (fever, headache, fatigue), then quickly progressing to severe neurological disease, including paralysis, delirium, convulsions, and loss of consciousness. Death generally occurs within 1–2 weeks of symptom onset. All four recorded human cases in Australia – three in Queensland (in 1996, 1998 and 2013) and the recent NSW case – have been fatal. There's no effective treatment once symptoms develop If someone is potentially exposed to bat lyssavirus and seeks medical attention, they can be treated with post-exposure prophylaxis, consisting of rabies antibodies and the rabies vaccine. This intervention is highly effective if initiated promptly – preferably within 48 hours, and no later than seven days post-exposure – before the virus enters the central nervous system. But no effective treatment exists for Australian bat lyssavirus once symptoms develop. Emerging research on monoclonal antibodies offers potential future therapies, however these are not yet available. Pre-exposure rabies vaccination, involving three doses over one month, is recommended for high-risk groups. This includes veterinarians, animal handlers, wildlife rehabilitators, and laboratory workers handling lyssaviruses. It's important for members of the public to avoid all direct contact with bats. Only vaccinated, trained professionals, such as wildlife carers or veterinarians, should handle bats. Public education campaigns are essential to reduce risky interactions, especially in bat-populated areas. If you get bitten or scratched by a bat, it's vital to act immediately. Wash the wound thoroughly with soap and water for at least 15 minutes, apply an antiseptic (such as betadine), and seek urgent medical attention. This tragic case in NSW underscores that while extremely rare, bat lyssavirus is an important public health threat. We need to see enhanced public awareness and ensure vaccination for high-risk groups, alongside ongoing bat monitoring and research into new treatments.
The Hindu
a day ago
- Health
- The Hindu
Kerala to launch antibody surveillance studies on Nipah virus
Nipah virus (NiV) has surfaced in Kerala yet again, making this the eighth appearance in as many years. Whether virus spillovers (single index case, with no secondary cases in the community), or outbreaks (spillover with subsequent cases), Kerala has primed its response to the virus, seamlessly managing early detection, limiting the transmission and successfully saving lives. However, in all these encounters with NiV, researchers have identified several missing links or knowledge gaps. These pertain to the exact virus spillover mechanism from bats ( the fruit bats of the Pteropus species are the proven natural reservoir hosts of NiV) to humans; the recurrence of the spillover events/outbreaks in a specific geographic belt in northern Kerala and how exactly human behaviour, land use and bat ecology interactions are facilitating the virus spillovers. 'We have toyed with several hypotheses regarding the spillover mechanism. Are direct spillovers possible in areas near bat colonies , such as through droplet transmission from bat secretions or poop? Can individuals be indulging in high-risk behaviours, such as consuming bat meat (evidence of NiV in internal organs of bats has been reported)?,' said T.S. Anish, a public health expert who heads the Kerala One Health Centre for Nipah Research and Resilience, Kozhikode. The possibility that NiV transmission to humans could be through fruits bitten by bats has remained conjecture at best because NiV has never been isolated in any fruit samples collected and tested during outbreak investigations in Kerala. NiV RNA has been detected in date palm sap in Bangladesh but live virus has never been isolated from any field samples. But the link between consumption of raw date palm sap in Bangladesh and human NiV infections is strongly supported by epidemiological and experimental evidence. Also, as NiV is an enveloped virus, its ability to remain infectious on a fruit in an outdoor environment is extremely fragile, said Dr. Anish Intermediate hosts? 'Our current thinking about NiV spillovers strongly leans to the fact that there is an indirect transmission route to humans, involving an indirect host. Ephrin B2, the main cell receptor used by NiV for infecting host cells is highly conserved in all mammals, which means that all animals like dogs or cattle or pigs could harbour the virus, as has been demonstrated in Malaysia and Bangladesh,' he pointed out. None of the animal samples sent so far to the National Institute of High Security Animal Diseases in Bhopal have so far turned out to be NiV positive. However, it is also a fact that NiV research is relatively nascent and that the research institutions in the country, including the National Institute of Virology, are still in the process of developing antibody markers and testing assays specific to NiV. PVNT platform Thus, while Kerala's public health response against NiV infections has been effective, the development of a novel pseudovirus neutralization test (PVNT) platform, based on a Vesicular Stomatitis Virus (VSV) system at the State's Institute of Advanced Virology (IAV), Thonnakkal has opened up new research possibilities on Nipah. IAV has developed a novel way of generating non-infectious Nipah virus-like particles (VLPs) as well as pseudovirions in the laboratory, which mimic the wild type NiV. These engineered 'ghost viruses' carry most of the characteristics of the virus, including the NiV structural proteins G, F, and M, except their ability to replicate (because it lacks the viral genome). VLPs and pseudovirions have long been recognised as effective platforms for studying cell binding and entry kinetics of the virus. These VLPs and pseudovirions mimic viral entry but can only undergo a single round of infection and cannot replicate and reproduce infectious viruses, making them safe to handle in standard Biosafety Level 2 (BSL-2) facilities. PVNT-based serological survey 'We are proposing a pseudovirus neutralisation assay-based serological survey among potential intermediate animal hosts and high-risk human populations in areas of previous NiV spillovers, with the collaboration of various stakeholders, including the departments of Health, Animal Husbandry, Forests and wildlife. The proposal is to collect healthy domestic animal blood samples (cattle, pigs, goats, dogs and cats) and human samples from within a few km radius of Nipah hotspots,' E. Sreekumar, the Director of IAV, told The Hindu. Serum samples will be tested using the IAV's VSV-based PVNT assays. The assay measures the ability of IgG antibodies in human/animal serum to neutralise these pseudovirions, thereby preventing infection of target cells. Infectivity and neutralisation, is quantified by measuring the expression of a reporter gene incorporated into the pseudovirus genome Positive PVNT results will indicate the potential of those animal species as intermediary hosts and such samples will be further tested against live Nipah virus in a BSL-4 facility with the help of NIV, Pune. This study is expected to provide robust data on NiV seroprevalence in high-risk human and animal populations in Kerala and open the doors to the mystery of NiV disease spillover and transmission pattern in the State. Futuristically, the successful validation of serological data and its integration with geo-spatial analysis will enhance Kerala's diagnostic and surveillance capabilities for NiV, it is hoped
Time of India
2 days ago
- Health
- Time of India
Nipah: Experts seek deeper eco studies
Kozhikode: Over the past year, four Nipah infections were reported in Malappuram, including the suspected death of an 18-year-old girl at Makkaraparamba on July 1. Now, deeper studies are being sought to examine whether repeated spillovers of the virus are being caused by ecological factors such as disturbances in bat habitats. Experts have stressed the need for better monitoring of Pteropus fruit bats, the natural carriers of the virus, along with efforts to protect their habitats and raise awareness to reduce human-bat contact. A study published in PLOS Global Public Health in December 2024 pointed out some key findings. It was led by experts including TS Anish, nodal officer of Kerala One Health Centre for Nipah Research and Resilience. The study said that four of the six Nipah outbreaks in Kerala (2018, 2019, 2023, July 2024) happened during El Nino years. All six took place between May and Sept, which is the fruit ripening season. It said that these patterns showed how environmental factors affect man-animal interactions and may lead to Nipah outbreaks. The study also noted that fear during Nipah outbreaks in Kerala led to harmful social behaviour. by Taboola by Taboola Sponsored Links Sponsored Links Promoted Links Promoted Links You May Like Giao dịch CFD với công nghệ và tốc độ tốt hơn IC Markets Đăng ký Undo It often caused conflicts between people and animals and ended with more bat habitats being damaged. People were found cutting trees used by bats and using firecrackers to scare them away. Another study in Malaysia said such actions could increase chances of human-bat contact and may cause infected bats to migrate to new areas. Faculty at Kerala Veterinary and Animal Sciences University's centre for wildlife studies (CWS) Dr George Chandy said that field studies conducted by the centre found evidence of destruction of bat roosts in Kozhikode and Wayanad. Dr Chandy said that the exact way Nipah spreads from bats to humans is still unclear. He said it is important not to disturb bat roosts. After every outbreak, it was seen that people destroyed bat habitats in many areas. During student fieldwork, some roosts found in pilot studies were found affected. Dr Chandy said that people had cut tree branches with bat roosts at Pazhassi Park in Mananthavady. Crackers and other methods were used to scare bats which might cause stress and increase virus spread. He said the two main actions needed now are to protect bat habitats and raise awareness to reduce interactions between humans and bats. Prejith K, Associate Professor at KVASU, said that ecological factors in the region should be studied more and added that climate change might be causing stress in bats. "Recurring cases highlight the need to examine if ecological factors including deforestation or land use changes are contributing to habitat loss of bats and inducing stress among bat populations," he said. He added that the growing number of fruit trees in house compounds, including non-native ones, could attract more bats. He said this needs to be studied to understand if it is leading to more human-bat contact.
