So far, however, Colorado hasn’t seen an unusual number of cases of West Nile virus, the main disease carried by mosquitoes in this part of the country. Mosquito surveillance is just starting, which makes it difficult to know whether the bugs have been able to take advantage of favorable conditions.

Colorado had a relatively mild winter, which likely allowed more mosquitoes to survive, said Jim Fredericks, senior vice president for public affairs at the National Pest Management Association.

When temperatures reach the high 80s, mosquitoes also mature faster, allowing the population to compound as more reach the age to lay eggs, he said.

“You can squeeze in more generations during a so-called mosquito season,” he said.

Mosquitoes need standing water to lay their eggs, so the state’s drought conditions would seem to work against them, Fredericks said. At the same time, they’re quite resourceful and will rely more on water pooling in manmade items if they don’t have a suitable pond available, he said.

“We end up having water sources around structures” when people water their gardens or cool off with a hose, he said.

While all mosquitoes may be annoying, the ones Coloradans need to worry about are from the Culex group of species, which transmit West Nile virus, said Greg Ebel, a professor of microbiology, immunology and pathology at Colorado State University’s Center for Vector-Borne Infectious Disease.

The previous two West Nile seasons were relatively severe, but right now, the limited data isn’t pointing to a repeat of that, Ebel said.

Jefferson County reported one case in early June, involving a person who was hospitalized, but survived. Last year, the state health department reported 286 cases, with half involving neurological complications. (The actual rate of complications is likely much lower, because most people don’t get tested for West Nile.)

Mosquito surveillance around Fort Collins started a week ago, and that first round didn’t pick up enough West Nile-infected Culex specimens to raise concerns, Ebel said. One week of data isn’t enough to draw conclusions, though, and local conditions can lead to different mosquito populations, he said.

“The warm winter might be concerning, but we don’t really know that yet,” he said. “It’s been a pretty dry spring.”

The Denver Department of Public Health and Environment said it will start trapping and testing mosquitoes for West Nile next week, as well as monitoring 70 water sites and applying chemicals if needed.

Public mosquito control, such as spraying water with substances that kill larvae, is highly effective in reducing populations and the odds of disease, Ebel said.

Individuals also can protect themselves by draining any standing water around their homes, avoiding outdoor activity between dusk and dawn, keeping window screens repaired and using an with the U.S. Environmental Protection Agency, such as DEET.

Typically, most of the state’s West Nile cases appear between June and September, though the season sometimes stretches further into the fall if warm weather lets mosquitoes keep flying and biting.

Jefferson County Public Health didn’t release any information about the person’s demographics or how sick they became. Most people who have West Nile virus never seek testing because they don’t feel sick, or they attribute symptoms such as fever and tiredness to a different illness.

In a small percentage of cases, the virus can , causing coma, paralysis or death. People over 60 and those with compromised immune systems are more likely to become severely ill.

People can reduce their odds of getting West Nile by wearing insect repellent and covering skin while outdoors; limiting activity at dawn and dusk; emptying any standing water around their homes; and repairing door and window screens as necessary.

Last year, , including 144 hospitalizations and 18 deaths. The number of cases varies widely from year to year, with 634 in 2023, but only 76 in 2024.

The department didn’t provide any information about the Denver resident who has West Nile. Most people don’t get tested for the virus, because they have either mild symptoms or none at all. In severe cases, the virus can invade the nervous system, causing paralysis, coma, or death. People over 60 and those with compromised immune systems are more likely to become severely ill.

Jefferson County Public Health also announced the first human West Nile cases of the summer in its jurisdiction. Three people in the county tested positive, but all are recovering at home, the agency said.

Eleven people in Colorado have tested positive for West Nile this year, including five who developed neurologic symptoms and three who needed hospital care, . One person, identified only as a Lafayette resident, died from the virus. The state’s count didn’t include the Denver or Jefferson County cases.

People can reduce their odds of mosquito bites by making sure window screens don’t have holes bugs could get through, wearing long sleeves and pants when outside, applying insect repellant with DEET and avoiding outdoor activities near dawn and dusk.

They can also help keep the mosquito population down by getting rid of standing water where the bugs can lay eggs. Moving sprinklers away from sidewalks or the street can reduce the formation of puddles, as can cleaning out gutters that could trap water. The health department advised people to empty and scrub, turn over, cover or throw away items that hold water outside, such as tires, buckets, toys and bird baths.

Those individuals likely contracted the virus from infected mosquitoes in late June, the said in a news release. While no mosquitoes have tested positive for West Nile in Adams County, neighboring counties have confirmed the virus’s presence.

Colorado’s West Nile season started early this year, with mosquitoes testing positive for the virus in Denver, and Weld County near Greeley and Johnstown earlier this month.

While West Nile can be fatal in rare cases, most people don’t show signs of infection. About 20% of people develop flu-like symptoms and fewer than 1% develop a serious, potentially deadly illness, Adams County officials said.

People 60 years and older and with certain medical conditions are at a higher risk for serious illness, and anyone who develops a severe headache or becomes confused should see their health care provider.

The best way to is to protect against mosquito bites. People can take precautions like using insect repellent, limiting time outdoors at dawn and dusk and wearing long-sleeved shirts and pants when near mosquitoes, Adams County officials said.

Mosquitoes breed in standing water, so emptying water from birdbaths, rain barrels, toys and flower pots at least once a week can also help limit the spread.

The Adams County Health Department is distributing free insect repellent at its Westminster clinic, 1401 W. 122nd Ave., and at community outreach events throughout the summer.

Mosquitoes are trapped weekly in three zones across Weld County and tested for the virus. Recently, mosquitos in Zone 1 (near Greeley, Evans, Kersey and LaSalle) and Zone 2 (near Johnstown, Milliken and Platteville) tested positive, according to a Weld County news release.

“The increasing hot weather often leads to favorable conditions for the Culex mosquito that carries West Nile virus,” Weld County Health Department Executive Director Jason Chessher said in the release. “The public needs to be vigilant, because West Nile virus has a permanent summer presence in Colorado.”

Health officials expect human cases to increase as the hot weather continues throughout July and August, the release states. .

Symptoms can appear three to 14 days after an infection. While most people exhibit no symptoms, anyone experiencing fever, headache, nausea, vomiting, muscle aches and weakness and rash should see a health care professional immediately, according to the release.

Health officials recommend following the four “D’s” to prevent mosquito bites:

• Drain standing water around your house, including from tires, cans, flowerpots, rain barrels, toys and clogged rain gutters.
• Dusk and dawn are when mosquitoes are most active. Limit outdoor activities and take precautions during dusk and dawn.
• Deet is an effective ingredient in repelling mosquitoes, though picaridin, IR3535, lemon oil, eucalyptus or para-menthane-diol also act as repellants.
• Dress in long sleeves, long pants and a hat where mosquitoes are active, the county said in the release.

For more information, including a map of mosquito zones and trapping and testing updates, go to .

Denver reported its first mosquito that tested positive for West Nile on Thursday, becoming the second Front Range county to confirm the presence of the virus this summer.

Not all counties set out mosquito traps, so Colorado residents can’t assume their local bugs don’t carry the virus if they haven’t heard about reported cases.

Mosquitoes need standing water to breed, so storms that leave puddles could benefit them. But the amount of rain is only one factor in how many people will become severely ill with West Nile, said Dr. Daniel Pastula, chief of neuroinfectious diseases and global neurology at University of Colorado School of Medicine.

Summer temperatures influence how active mosquitoes are, and how many pick up the West Nile virus depends on whether birds passing through Colorado have active infections, he said.

“We haven’t been able to predict ahead of time when there’s going to be a bad West Nile season,” he said.

Residents along the Front Range may get a bit of warning from counties’ mosquito traps, though. When bugs test positive for West Nile, that signals the risk is up, and people need to be especially vigilant about avoiding mosquito bites, Pastula said.

Larimer County found its on June 23. Typically, West Nile season starts in early to mid-July.

Most West Nile cases in Colorado happen between July and September, though mosquitoes can live until the first snow or hard freeze, Pastula said.

About 80% of West Nile cases are asymptomatic or have mild symptoms that people typically don’t seek treatment for. In about one in 100 cases, though, the virus invades the brain or spinal cord, and about one in 1,000 infected people die, Pastula said. Those who survive a severe case sometimes experience paralysis or cognitive damage, he said.

Colorado recorded 76 West Nile cases and zero deaths last year, according to health department data. But the state saw 634 cases and 51 deaths from the virus in 2023 and 207 cases and 20 deaths in 2022.

People who are over 50, have compromised immune systems, or have chronic conditions such as diabetes or kidney disease are at higher risk for the virus to infect their nervous systems. But occasionally, people with no obvious risk factor become seriously ill, Pastula said.

The western Great Plains and the Front Range have higher than expected rates of severe West Nile, possibly because the mosquito species that live here are more aggressive toward people than those on the coasts, he said.

“I have seen healthy 20- and 30-year-olds with severe West Nile disease and permanent neurological damage,” he said. “It is much better to avoid getting this.”

People can protect themselves by and long pants and sleeves while outside. Limiting outdoor activity around dawn and dusk also lowers the chances of a bite.

Using air conditioning or screens over open windows will keep mosquitoes out, and dumping any standing water on your property will limit opportunities for them to breed.

The two grants total about $1.7 million. One is to study vaccine hesitancy in Alaskan Native communities, and the other is a partnership with Columbia University to study the link between diabetes and Alzheimer’s disease.

The National Institutes of Health are the world’s largest funder of medical research, distributing $35 billion in in grants in 2023.

, the Trump administration ordered the institutes to halt meetings to review about $1.5 billion in upcoming grants. It also announced that only 15% of grant funding could go for , such as , though a federal judge temporarily blocked that order. Supporters of the policy said limiting overhead spending would make more money available for research, while critics said it would make some types of labs impossible to fund.

The NIH has terminated grants to study ; for work at Columbia University, because of anti-Israel student protests; and for research in South Africa, because the administration believes the country is persecuting white citizens.

Some scientists also have reported receiving feedback that they shouldn’t pursue grants for research involving mRNA vaccines. The Pfizer and Moderna COVID-19 vaccines, which , use mRNA technology.

Greg Ebel, director of Colorado State University’s Center for Vector-Borne Infectious Diseases, said he doesn’t know of any other local projects that have definitively lost their funding, but uncertainty about government support for research will push young people out of the field. He spoke during a roundtable Tuesday on the Anschutz campus with Colorado Sen. John Hickenlooper, a Democrat.

“Nobody knows what to expect,” Ebel said.

Other researchers who spoke said the pharmaceutical industry and foreign powers would try to scoop up young people who couldn’t find funding for their research. Without their work, the United States could lose out on the kinds of advances that now allow most children with cancer to grow up, said Dr. Lia Gore, an oncologist who conducts clinical trials at Children’s Hospital Colorado.

“Fifty years ago, childhood cancer was uniformly fatal. There were no survivors,” she said.

Thomas Morrison, who is working on new vaccines and antiviral treatments on the Anschutz campus, said his department paused hiring while leaders sort out whether the NIH will continue funding their work. They’re trying to develop vaccines and treatments that work on multiple types of viruses, in the hope of having something that will work if a new type of flu caused a pandemic, for example.

“We may have funding, but it’s not clear that’s going to be there tomorrow,” he said.

Judy Regensteiner, who also works on the Anschutz campus, said she worries the grant that funds her work could disappear. The grant covers the salaries of young researchers working in women’s health, though Regensteiner’s work on sex differences in diseases such as diabetes affects both women and men, she said.

“It’s the uncertainty that’s so hard right now,” she said. “It’s painful to me, and especially to the early-career scientists” funded by the grant.

Hickenlooper said he believes Congress will push back against deep cuts to research, because significant numbers of Republicans support medical science, though no one has put together a bill or framework to get the NIH grants flowing again. The system of federal grants for research at universities allowed the United States to lead the world in science, he said.

“You’ve got to continue the investments that have got you there,” he said.

If the country doesn’t fund basic science, it will lose the ability to respond quickly to emergencies, Ebel said.

His lab is studying how to control mosquitoes with less insecticide, and has equipment that nearby counties can use to monitor for West Nile virus in their mosquito populations. Early in the pandemic, they repurposed it to test nursing home workers for COVID-19, possibly saving lives by preventing them from bringing the virus to vulnerable people, he said.

Basic research “gives us the ability to be creative and flexible and nimble in the face of threats,” he said.

The Denver Department of Public Health and Environment didn’t share any information about the person, who was the first in the city with a confirmed West Nile case this year.

Typically, only people with more severe illnesses get tested for West Nile, because most infected people either don’t get sick or have general flu-like symptoms. In the worst cases, the virus invades the nervous system, sometimes causing coma or death.

The department had urged caution in early August when it found mosquitoes infected with West Nile in the city. People can protect themselves by:

• Throwing out water that gathered in items on their property, such as flower pots and toys, and cleaning those items

• Avoiding hitting sidewalks and driveways while watering their lawns, because pools can form in uneven pavement

• Using insect repellent with DEET during outdoor activities

• Making sure door and window screens are in good repair

• Avoiding outdoor activities at dawn and dusk

• Wearing long pants and sleeves when outside

Arapahoe County reported the first case in the state in late June, marking an early start to the West Nile season. The season hasn’t been particularly severe so far: 13 people have tested positive, including seven who needed hospital care, but none has died, . The state’s data doesn’t yet include the Denver case.

Jefferson, Larimer, Weld, Delta, Kit Carson, La Plata and Mesa counties have also reported cases.

Last year, 634 people tested positive for West Nile and 51 died, making it the worst year for both infections and deaths since 2003.

Most people never know they have West Nile virus, because they either don’t get sick or have general flu-like symptoms. In a small percentage of cases, though, the virus invades the nervous system, causing seizures, paralysis, coma or death. People over 50 and those with compromised immune systems are at higher risk.

The Denver Department of Public Health and Environment urged people to protect themselves by:

• Using an insect repellant that contains DEET
• Wearing long sleeves and long pants in areas likely to have mosquitoes
• Avoiding going outdoors around dusk and dawn
• Draining any standing water around their homes

The West Nile season started early this year, with a human case confirmed in Arapahoe County in June. So far, the and four hospitalizations, but no deaths.

Last year was unusually severe for West Nile virus, with 634 known cases, 386 hospitalizations and 51 deaths in Colorado.

Health officials monitor mosquito traps in three parts of the county — zone one, including Greeley, Evans, Kersey and LaSalle; zone two, including Johnstown, Milliken and Platteville; and zone three, including Firestone, Dacono and Fort Lupton.

According to a news release from Weld County, mosquitos trapped in zones two and three have tested positive for West Nile. Currently, there are no human cases of the virus in Weld County.

“The increasing hot weather often leads to favorable conditions for the Culex mosquito that carries West Nile virus,” Weld County Health Department spokesperson Jason Chessher said in the release. “The public needs to be vigilant because West Nile Virus has a permanent summer presence in Colorado.”

Last year was Colorado’s worst West Nile virus season since 2003, when the virus arrived in the state. The state had 634 known cases in more than half of the state’s counties — 51 of those people died and 386 were hospitalized.

Arapahoe County reported the first known human case of West Nile virus in Colorado for 2024 in June, marking an early start to the mosquito-borne disease season. Typically, Colorado doesn’t see its first West Nile cases until July, and they take off in August.

To prevent infection with West Nile virus county health officials and the Centers for Disease Control and Prevention recommend:

• Wearing insect repellant with DEET or another ingredient approved by the Environmental Protection Agency during outdoor activities
• Avoiding spending time outdoors around dawn and dusk, when mosquitoes are most active
• Using mosquito netting when camping
• Avoiding stagnant water sources, such as ponds, and checking around your home to regularly drain standing water
• Wearing long-sleeved shirts and long pants for outdoor activities and treating clothes with permethrin
• Draining flowerpots, tires and other items that collect water, which mosquitoes use to breed
• Keeping window screens in good repair

Most people who have the virus don’t get sick, making West Nile difficult to track.

Only 20% of people bitten by mosquitoes carrying the virus will develop symptoms — including fever, headaches, body aches, skin rashes and swollen lymph glands, according to the CDC.

While most people infected with the virus don’t get sick, symptoms for those who do appear between two days and two weeks after infection, CDC officials said.

About one in 150 people who are infected develop a severe illness or life-threatening symptoms, including high fevers, tremors and convulsions, muscle weakness, paralysis and inflammation of the brain and spinal cord.

Less than 1% of people with West Nile cases die, according to the CDC.