West Nile Virus wey dey spread through mosquito and no get cure – wetin to know about am

Late August 1999 wen di infectious diseases physician in di New York City borough of Queens report two cases of viral encephalitis, or brain inflammation, to di city Department of Health and Mental Hygiene. One urgent investigation start afta dem identify similar cases for neighbouring hospitals. Estimate show say in total, dis mysterious epidemic ultimately infect approximately 8,200 pipo across di city. Na di first outbreak of West Nile virus in di western hemisphere.

No one know exactly how di virus enta US from parts of Africa, di Middle East, southern Europe and Russia wia e don dey circulate for decades, but research don show say birds na di main carriers of di virus. Mosquitoes contract di virus wen feeding on infected birds, bifor dem go pass am to humans.

Since dat initial outbreak for 1999, more dan 59,000 US cases and more 2,900 deaths from West Nile virus don dey, although some estimates place di real number of infections at more dan three million.

Now, growing concern dey say West Nile outbreak in di US and around di world go become more frequent sake of climate change. Studies don show say warmer temperatures fit increase mosquito development, biting rates and viral incubation within mosquito. For Spain, wia di virus dey endemic, fresh outbreak for 2020 dey followed by prolonged period of escalating circulation.

Dis don lead to particular concern becos while infections dey predominantly no dey bring symptoms as only one in five pipo dey experience mild symptoms, severe cases fit result in lifelong disability. In around 1 in 150 pipo, di virus fit invade di brain and central nervous system, causing life-threatening inflammation, and in many cases, brain damage.

In particular, pipo wey dey immunocompromised in some way, ova di age of 60, or get diabetes or hypertension, dey particularly vulnerable. “Wit hypertension, we tink say increased pressure in di brain allow di virus to cross di blood brain barrier more readily,” Murray tok.

Pipo wey no get strong immune system, wey don pass 60 years, or get diabetes or hypertension, dem dey veri vulnerable. “For pipo wey get hypertension, we tink say di high pressure for brain fit make di virus cross di blood-brain barrier easier,” Murray talk.

Afta following patients wey dey suffer from severe cases of West Nile viral infection for many years, Murray say di resulting inflammation fit ultimately cause such severe brain atrophy or shrinkage wey scans often show similar patterns of damage to pipo wey don suffer traumatic brain injuries.

“For pipo wit severe disease, about 10% go die from di acute infection and around 70-80% go experience long-term neurological consequences,” Murray tok. “For pipo wey survive, e no dey get beta, e dey get worse. Pipo report depression, personality change, tins like dat,” she tok.

Yet despite dia inherent risk, no vaccine or even any dedicated treatment fit help pipo wey dey suffer from di infection. “E don really become neglected disease,” Murray tok. “Ds year alone, I don meet so many patients wey dem newly diagnosed wit West Nile, wey dey ask, ‘Wetin we fit we do?’ And I go be like, ‘Notin’. Na just supportive care and e dey break my heart to tell dem dat,” she tok.

Wen e come to di lack of preventative measures against West Nile infections, perhaps one of di biggest ironies be say safe and highly effective vaccines dey available for horses for di past 20 years.

Between 2004 and 2016, dem perform nine clinical trials on different human vaccine candidates, two dey launched by di French pharmaceutical company Sanofi and di remainder funded by either biotech companies, academic institutions or various US govmental organisations. Yet despite say all of dem dey generally well-tolerated and induce immune response, none of dis trials make am to Phase 3 clinical trial.

Dis na di final and most crucial hurdle bifor vaccine fit dey authorised, and involve testing if treatment dey effective. Di last of dis trials, sponsored by di US National Institute of Allergy and Infectious Diseases, no progress any further dan Phase 1 – di first step, wey usually aim to find out if di intervention dey safe.

Carolyn Gould, wey be medical officer wit CDC Division of Vector-Borne Diseases for Fort Collins, Colorado, say di sporadic and unpredictable nature of West Nile outbreak na big hurdle, as di virus need to dey circulate at dat particular time to dey able to prove say di vaccine dey work.

“Some trials start wen no plenti cases dey,” Murray tok. “But later, outbreak bin dey for 2012 wia we bin get ova 2,000 cases for Texas alone, and ova 800 of dem na severe cases. So if dem bin wait for small years, dem for get all di participants wey dem bin need,” she tok.

For 2006, one major study of vaccine cost-effectiveness conclude say universal West Nile virus vaccine programme dey unlikely to save di healthcare system moni. Gould believe say di sheer cost of developing vaccine, combined wit uncertain benefits or financial return from pharmaceutical company perspective, na major problem.

However, some possible alternatives don dey offered in recent years. Some scientists don recommend dedicated vaccine programme for ova 60s wey dey at greater risk from di virus, while Gould propose programme aimed at specific regions in di US wia virus-carrying mosquitoes dey most prevalent.

In addition, Gould believe say di increasing evidence surrounding di longer-term consequences of West Nile virus-induced neurological damage fit make funding vaccine development more appealing. More recent estimates don suggest say di economic burden of hospitalised West Nile virus patients na $56 million (£42 million), and di short and long-term costs fit exceed $700,000 (£530,000) per patient.

“More recent studies show e fit dey cost-effective if dem deploy am to high-risk groups for specific geographical locations,” Gould tok. “From manufacturer standpoint, e go dey important to consider di high numbers of pipo at increased risk for West Nile virus disease wit serious consequences, wen conducting sales forecast,” she tok.

Based on di ongoing fatalities and neurological disabilities wey di virus dey cause, Paul Tambyah, president of di International Society for Infectious Diseases, describe di current inability to find solution as “lack of imagination”.

“Evribodi dey tink say you gatz do dis big phase 3 trial for US, but e no easy for disease wey only show for two and a half months for year, and e dey unpredictable too. Some years you go get big outbreak, but oda years you no go get,” Tambyah tok.

Instead Tambyah propose large international trial wit hundreds of different trial sites, not just di US but in parts of Africa wia di virus dey endemic, as more effective way of gathering di evidence required.

While e go require several million dollars of funding to launch such initiative, e say e fit dey possible wit di help of public-private partnerships, pooling togeda di resources of various govments of affected kontris and small and medium sized pharma companies to help reduce di financial risk wey dey involved, in case the trial no prove say e dey work.

“E get few possible mechanisms out dia to make dis happun,” e tok. “E just require di willpower to do somtin about am.”

Anoda big mata na to find beta treatments for people wey dey experience serious sickness because of West Nile viral infection. Murray tok say while some drug candidates bin dey developed based on artificially generated antibodis against di virus called monoclonal antibodies, dem no progress further dan rodent studies, and developers face di same tricky hurdles like vaccine manufacturers wen e come to devising a suitable clinical trial.

Murray feel say di most urgent need na drug wey fit clear di virus and also help calm down di serious inflammation for di brain wey dey cause plenty neurological wahala. She suspect say for some cases, di virus dey settle inside di brain nerve cells, and e no easy to attack am.

“E dey cross di blood-brain barrier and set up within di brain, and dat na wia you get di inflammation and damage,” she tok. “Di problem be say a lot our existing antivirals no fit reach di brain so e no fit get to dat space wia e need to dey effective.”

But dia fit be alternative possibilities. Tambyah feel say we fit take many lessons from di Covid-19 pandemic, wia despite di global arms race to develop antiviral against di Sars-CoV-2 virus, one of di most effective treatments turn out to be cheap steroid called dexamethasone. Di effectiveness dey identified by di Recovery trial in di UK, wey examine variety of possible treatments.

Tambyah wey don treat many patients wit brain inflammation as part of im role as senior infectious diseases consultant at di National University Hospital for Singapore, believe say finding di right steroid for reducing di inflammation fit ultimately help many patients to recova. “West Nile virus na flavivirus and e no get licensed antiviral at di moment for any of di flaviviruses – dengue, Zika or Japanese encephalitis,” e tok. “I tink steroids go be di future.”

Ultimately though, more data dey needed to identify di most appropriate drug for tackling West Nile virus, and Tambyah suggest say dem fit do dis through similar study to di Recovery trial.

“We fit potentially recruit patients wit encephalitis from West Nile virus and include various interventions, some steroids, monoclonal antibodies as well, and hopefully e fit give us answer,” Tambyah tok. “If di will to do somtin about am dey, sufficient funding from di goments of affected kontris, e fit happun,” e tok.

Ultimately Murray and Tambyah dey hope say di spotlight wey dey on West Nile virus as a result of Fauci illness go help convince policymakers to devote more funding towards dis neglected disease.

“Dis virus dey here to stay and we go dey get dis outbreaks,” Murray tok. “If someone like Fauci, wey dey in position wia pipo listen and respect am, fit tok about dis, e fit help give additional push for di funding to study di virus and allow scientists to focus on vaccines and therapeutics. Becos na 25 years now since West Nile start for di United States and we still no get anytin.”