It all started one day in June 2007, with a sudden fever and severe vomiting, said David Hancock. He should have gone to hospital, immediately. But he didn’t — he thought: If this is a common infection, I’ll get over it. 

Then he realized it wasn’t a common infection.

But it still took 10 days for doctors to make a reliable diagnosis. During these 10 days the then 49-year-old fell into a coma and suffered heart failure — multiple times. His lungs filled with fluid, and his brain became inflamed.

“I was on the other side, with one foot in the other world, so to speak,” said David of the experience, when we spoke in 2025.

David had contracted West Nile virus from a mosquito bite on his very own doorstep in Glendale, a city near Phoenix, in the US state of Arizona.

A perfect pair: Mosquitoes and West Nile fever

Unlike malaria, dengue, yellow fever or the Zika virus, West Nile virus (WNV) is not transmitted by invasive mosquitoes that have traveled north from the Tropics. WNV is mainly transmitted by native mosquitoes of the genus Culex.

But WNV does originate from the Tropics. It was first detected in 1937 in the West Nile region of northern Uganda and named after that place where it was found.

Migratory birds then brought WNV to Europe and the US, where it was first recorded in 1999. Today, it is the main cause of mosquito-borne diseases in the US.

Tropical WNV is transmitted by Culex pipiens, a common mosquito. It is a European and North American native and a particularly good “vector” for virus. 

If, for example, a mosquito bites a bird that is infected with WNV, and the mosquito gets infected itself, the virus will replicate in the mosquito, and the mosquito will then pass on the virus to another animal when it takes a blood meal. That can be another bird or a horse. Or a human, as it was in David’s case.

WNV infection can go unnoticed — it is an asymptomatic infection — but an average of 1,300 people in the USA fall seriously ill with WNV every year. And 130 of them die.

Irony of David’s fate: His brother Bob is a mosquito researcher

In addition to fever and vomiting, David eventually became unable to swallow. Finally, his wife, Teri, resolved to take him to hospital. Big mistake.

“What we should have done is call an ambulance and have them take me, so I would have moved to the head of the triage line, but I went to the emergency room, where I waited hours and hours and hours to be admitted, and it almost cost me my life,” said David.

At some point, Teri went home to feed their dog. When she returned to the hospital, she learned that David’s heart had stopped twice, and that he was now on a ventilator in intensive care. 

David’s fever was so high that the temperature in the room was chilling. His doctors expected him to die.

So, Teri got the whole family together: her parents, David’s parents, and his brother Bob. 

Bob Hancock is a biologist and — ironically — has been researching the behavior of mosquitoes for decades.

“When the news got around that David had contracted West Nile, everyone asked: ‘Are you sure it’s David?'” said Bob. Because, after all, it was Bob who was always surrounded by mosquitoes in a South American jungle. 

“I do really admire my subject,” said Bob. “I don’t study [mosquitoes] because I want to destroy them. I’m interested in them.”

Climate change: Better conditions for mosquitoes and viruses to thrive

Most mosquito bites are harmless. It’s only the clinical cases that get counted — “that is, when someone has to go to the doctor or hospital,” said Bob — or if an infection becomes fatal. Those are the cases we know about. The number of unreported cases — of those people who become infected without realizing it — is probably quite high. Those cases don’t get recorded.

But the dangers of infection are very real. David’s illness was a traumatic experience both for both him and his wife, Teri. Teri still cries when she recalls the days she thought her husband was about to die.

Bob’s life also changed after his brother’s illness. 

“I would have been happy, just to be this fun-loving mosquito lover, who was only interested in jungle mosquitoes that fly around and do cool things,” he said. 

But since his brother’s infection, Bob’s interests have turned to mosquito-borne disease transmission. “I’ve matured into the medical entomologist I am today,” he told DW.

These days, Bob keeps a close eye on developments in the US. Climate change is providing tropical mosquitoes and viruses with ever better living conditions in northern climes now.

For instance, it will have taken 10 years for the Aedes species of mosquito to migrate from Southern California to San Francisco — a distance of about 643 kilometers (400 miles). 

Aedes mosquitoes, which originally come from the tropics, are potent carriers of disease, including dengue, yellow fever and Zika. 

“There’s no reason for us to believe that the mosquitoes are going to come and the disease is not,” said Bob.

Mosquitoes are not dangerous, viruses are

David’s life has changed since his infection. 

When he woke up from his coma, he could neither breathe nor speak on his own. He was emaciated and couldn’t walk. It took him nine months before he could walk again. He is still unable to swallow without help.

Teri says David has become introverted, unlike the man she married. He is different. They assume the virus left damage in David’s brain.

But one thing hasn’t changed: David still gets bitten by mosquitoes. The only thing that helps is mosquito spray, and lots of it. 

“I absolutely hate [mosquitoes],” said David. And Teri hates them, too. Who can blame the couple?

And what about Bob? 

“I still love mosquitoes. They’re just trying to get a meal and raise a family,” he said. “I do hate the virus, though. I mean, I could hate the birds, too, right? Because the mosquito that gave it to my brother got it from a bird.” (DW)

The post Mosquitoes: The most dangerous animals in the world? appeared first on Newswire.

A drug used to treat a rare inherited disease has been found to make human blood toxic to malaria-carrying mosquitoes. It could provide another tool to reduce deadly insect populations.

Mosquitoes are considered the deadliest animal on the planet — carrying diseases that kill more than one million people a year.

Scientists have found that a drug called nitisinone, which is used to treat people with a rare inherited disease called tyrosinemia, makes human blood toxic to mosquitoes.

Although it doesn’t prevent the transmission of the malaria parasite Plasmodium, nitisinone is now being considered for further field tests as a chemical control to reduce the number of insects capable of spreading the disease.

What is the mosquito-killing drug?

Nitisinone is used to treat hereditary tyrosinemia type 1, which is a disease where people have too much tyrosine in their blood.

Lab tests found that when a mosquito bites someone who’s been taking nitisinone, the presence of the drug prevents the insect from being able to digest the human “blood meal” — 24 hours later, the insect dies. Nitisinone is toxic to mosquitoes in a way that it isn’t to humans.

Compared to ivermectin, another chemical that has been investigated as a mosquito vector control, nitisinone lasts longer in the bloodstream.

It’s also versatile, as it can be vaporized and sprayed on surfaces, meaning it can act like an insecticide.

An insecticide in your blood?

While field tests are required to ensure the drug is effective in malaria-prone areas, the early findings suggest it could be promising as a cheap and effective agent to control mosquito numbers.

Importantly, it appears effective against mosquito species that have developed resistance to other control chemicals.

“It kills insecticide-resistant mosquitoes. There are a few insecticides that have been used in the field for decades [but] there are resistant [mosquito] lines in the community,” said Alvaro Acosta-Serrano, the joint supervisor of the study, based at Notre Dame University, US.

“We tested those resistant lines with nitisinone and they are almost as equally susceptible as the susceptible lines of mosquitoes. It brings a lot of benefits, not only to mention that it performs better than ivermectin.”

Anna Last, an associate professor in infectious diseases at the London School of Hygiene and Tropical Medicine, who wasn’t involved in the study, said the findings were promising, particularly given results from recent field tests of ivermectin in vulnerable communities in Africa.

“It’s a very relevant piece of work, I think, and does follow on from the slightly disappointing results from the majority of field trials looking at ivermectin, which showed that it didn’t perform in the way that we had anticipated and hoped, in the field,” Last told DW. (DW)

The post A new drug makes your blood toxic to mosquitoes appeared first on Newswire.

A new species of mosquito that drinks blood from frogs has been detected in the Mirigama area in the Gampaha District, it was reported.

Entomology Officer Gayan Sri Kumarasinghe said that identified as Uranotaenia Trilineata, it is the smallest mosquito species currently reported in Sri Lanka.

Stating that they are 2-3mm in size, Kumarasinghe said the latest detection has increased the number of mosquito species identified in Sri Lanka to 156.

He further revealed that the mosquito species was found in South Korea nearly 108 years ago and was later detected in Thailand after which it has now been detected in Sri Lanka. (NewsWire)

The post New mosquito species detected in Sri Lanka appeared first on Newswire.