WEDNESDAY, July 24, 2024 (HealthDay News) — Arizona health officials are reporting an increase in hantavirus infections, which are spread by rodents and can cause severe respiratory illness.

In a recent health alert, the Arizona Department of Health Services announced there have been seven confirmed cases and three deaths in that state in the past six months.

While most hantavirus cases are reported in the Western and Southwestern United States, Arizona has one of highest numbers of reported infections in the country, according to the U.S. Centers for Disease Control and Prevention. From 2016-2022, there have been 11 hantavirus cases in Arizona, according to state health officials.

“Hantavirus is a rare but important cause of serious, even fatal respiratory infection,” Dr. Aaron Glatt, chief of infectious diseases at Mount Sinai South Nassau Hospital in New York, told NBC News.

“It is transmitted by various rodents, especially the deer mouse, and can cause mild disease, but it does cause fatal illness in a significant percentage of people who acquire this illness,” he noted.

Between 1993 and 2021, the CDC has reported a total of 850 hantavirus cases, or roughly 30 cases a year.

Trish Lees, public information officer at Coconino County Health and Human Services in Arizona, told NBC News that the increase in hantavirus cases may be due to shifts in rodent populations.

However, cases do tend to occur more in the summer because of increased rodent activity and people coming into contact with rodents more often, Lees explained.

Climate change, such as the extreme heat waves that have been sweeping across the county this summer, may also be partly to blame, experts theorized.

Dr. Camilo Mora, a professor in the department of geography and environment at the University of Hawaii at Mānoa, noted that people aren’t the only ones who seek shelter when it gets really wet or hot outside.

“Many carrying-disease species get on the move with climate change — so while for any specific case it is difficult to conclude the role of climate change, climate change has all the attributes to cause outbreaks of vector-borne diseases,” he told NBC News.

The hot weather may have also worsened the illnesses after people were infected because of dehydration or other factors, Glatt added.

Exactly how does hantavirus spread? Particles containing the virus get into the air when urine, saliva or feces from deer mice are stirred up. Once a person is infected, the virus can trigger hantavirus pulmonary syndrome (HPS).

The syndrome was first recognized in 1993 after a mysterious illness infected members of a Navajo tribe who lived on the border of New Mexico and Arizona. Approximately 80% of people who were infected died at the time.

Symptoms can appear one to eight weeks after exposure and include:

• Fever

• Fatigue

• Muscle aches — especially in the thighs, back and shoulder

• Nausea, vomiting and abdominal pain

Left untreated, the illness can infect the lungs and cause fluid to “leak” through blood vessels and fill up the respiratory tract. That, in turn, causes shortness of breath, chest tightness and cough, according to the American Lung Association.

Approximately 38% of people who develop lung symptoms may die from the disease.

What can be done to guard against infection?

“The best way to prevent infection with this illness is by carefully disinfecting and cleaning up any waste products from the rodents and by not coming into contact with them,” Glatt said.

When entering a place that’s been closed up for a long time, take care to air out the space for 30 minutes, the Wyoming Department of Health warns.

If the space is very dirty or full of mice, take extra care by wearing gloves, shoe covers, coveralls and N95 masks before cleaning.

More information

The U.S. Centers for Disease Control and Prevention has more on hantavirus.

SOURCES: Arizona Emergency Information Network, news release, July 23, 2024; NBC News

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