It all started one day in June 2007 with a sudden fever and severe vomiting, David Hancock said. He should have gone to the hospital immediately. But he didn’t do it – he thought: If this is a common infection, I’ll get rid of it.
Then they realized that this was not a common infection.
But it still took 10 days for doctors to make a reliable diagnosis. During these 10 days the 49-year-old man slipped into a coma and suffered heart failure multiple times. His lungs filled with fluid and his brain swelled.
“I was on the other side, I had one foot in another world,” David said of his experience when we spoke in 2025.
David became infected with West Nile virus through a mosquito bite on the doorstep of his home 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 Zika virus, West Nile virus (WNV) is not transmitted by invasive mosquitoes that have come north from the tropics. WNV is spread primarily by native mosquitoes of the genus Culex,
But WNV originated from the tropical region. It was first found in 1937 in the West Nile region of northern Uganda and named after the place where it was found.
Migratory birds then brought WNV to Europe and the Americas, where it was first recorded in 1999. Today, it is the leading cause of mosquito-borne diseases in the US.
Tropical WNV is transmitted by culex pipiensA common mosquito. It is native to Europe and North America and is a particularly good “vector” for viruses.
For example, if a mosquito bites a bird infected with WNV, and the mosquito itself becomes infected, the virus will replicate in the mosquito, and the mosquito will then transmit that virus to another animal when it takes a blood meal. It could be another bird or a horse. Or a human being, as in the case of David.
WNV infection may go unnoticed—it is an asymptomatic infection—but an average of 1,300 people in the United States become seriously ill from WNV each year. And 130 of them die.
The irony of David’s fate: his brother Bob is a mosquito researcher
In addition to fever and vomiting, David eventually became unable to swallow. Eventually, his wife Terri decided to take him to the hospital. big mistake.
David said, “What we should have done was call the ambulance and have them take me, so I would have gone to the head of the triage line, but I went to the emergency room, where I waited for hours and hours to be admitted, and it almost cost me my life.”
At some point, Terry went home to feed her dog. When she returned to the hospital, she learned that David’s heart had stopped twice, and he was now on a ventilator in intensive care.
David’s fever was so high that the temperature of the room was getting cold. His doctors expected him to die.
So, Terry got the whole family together: his parents, David’s parents, and his brother Bob.
Bob Hancock is a biologist and – ironically – has been researching mosquito behavior for decades.
“When the news broke that David had contracted West Nile, everyone asked: ‘Are you sure it’s David?'” Bob said. Because, after all, it was Bob who was always surrounded by mosquitoes in the South American jungle.
“I really admire my subject,” Bob said. “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 breed
Most mosquito bites are harmless. Only clinical cases are counted — “that is, when someone has to go to a doctor or a hospital” — or if an infection turns fatal, Bob said. These are the cases we know about. The number of unreported cases – the number of people who are infected without knowing – is probably much higher. Those cases are not registered.
But the risks of infection are very real. David’s illness was a traumatic experience for both him and his wife, Terri. Terri still cries when she remembers the days when she thought her husband was going to die.
Bob’s life also changed after his brother’s illness.
He said, “I would have been happy being this fun-loving mosquito lover who was only interested in forest mosquitoes that fly around and do cool things.”
But since his brother’s infection, Bob’s interest has turned to mosquito-borne disease transmission. “Today I have matured and become a medical entomologist,” he told DW.
Bob keeps a close eye on the developments in America these days. Climate change is now providing tropical mosquitoes and viruses with better living conditions in northern climates.
For example, it will take 10 years aedes The mosquito species migrates from Southern California to San Francisco – a distance of about 643 kilometers (400 mi).
aedes Mosquitoes, which originally come from the tropics, are potent carriers of diseases including dengue, yellow fever and Zika.
“There’s no reason for us to believe that mosquitoes will come and disease won’t come,” Bob said.
Mosquitoes are not dangerous, viruses are dangerous
David’s life has changed since the infection.
When he woke up from the coma, he was neither able to breathe nor speak. He had become weak and could not walk. It took nine months for him to walk again. He is still unable to swallow without help.
Terry says that unlike the man she married, David has become an introvert. He is different. They believe the virus has caused damage to David’s brain.
But one thing hasn’t changed: David still has to beg from mosquitoes. The only thing that helps is mosquito spray, and lots of it.
“I absolutely hate [mosquitoes],” David said. And Terry hates them too. Who can blame the couple?
And what about Bob?
“I still like mosquitoes. They’re just trying to get food and raise a family,” he said. “I hate viruses, though. I mean, I might as well hate birds, right? Because the mosquito that gave it to my brother got it from a bird.”
This article was translated from the original German-language version.