Hill County reports first confirmed human West Nile virus case

With West Nile virus season in full swing and the first confirmed case recorded in Hill County this week — the same week the first West Nile-caused death was reported in the state — people are urged to take precautions and do what they can to reduce the number of mosquitoes in the area.

The Hill County Health Department reported in a press release that as of Aug. 29, 19 human cases of the virus have been confirmed in Montana.

The Associated Press reports that an elderly man died from the virus in Billings, the first West Nile-caused death in Montana since 2016, when two people died from the virus.

The West Nile Virus season typically begins in July in Montana and runs through October. In this area, the virus is transmitted by the Culex tarsalis mosquito that flies at night, although Hill County Mosquito Control District Supervisor Terry Turner said another mosquito that flies during the day, Aedes vexans, could also carry the virus.

The mosquito district sprays to kill adult mosquitoes with a spray derived from chrysanthemums, which is generally harmless to people unless they are allergic to the flowers. The district also provides pellets for people to put in standing bodies of water, pellets that prevent the mosquito larvae from turning into adults.

Culex tarsalis mosquitoes have tested positive for West Nile in many Montana counties including Blaine and Hill.

The Hill County Health Department again urged people to follow “the four Ds” of West Nile prevention, dusk/dawn, dress, DEET and drain.

People are urged to use special care during peak mosquito hours, from dusk to dawn. People should avoid outdoor activity in those times and, if outside, protect themselves from bites.

People should wear long-sleeved shirts and pants to reduce the amount of exposed skin and reduce the chance of being bitten.

People should cover exposed skin with a repellent containing DEET, which is the most effective against mosquito bites. Other repellents are available, including oil of eucalyptus and picaridin. Turner said a new repellant known as Moskito Care seems to be very effective and is attractive because it has a more pleasant smell.

The last “D” is drain. People are urged to drain any standing water on their property, make sure gutters drain properly and regularly change water in pet dishes and decorative items.

The Hill County Health Department release said the number of West Nile virus human infections in Montana varies from year to year. Since 2003, when WNV tracking began, Montana has had two years with more than 200 cases reported: 2003–228 cases and 2007–201 cases. The average number of cases in Montana for the time period 2003-2017 is 36. In nine of the 15 year reporting period, there were less than 10 cases reported for the year. Last year, Montana had 11 human cases of WNV reported.

For more information on the virus, visit the Montana Department of Public Health and Human Services Website at: https://dphhs.mt.gov, or call the Hill County Health Department 400-2415 or the Hill County Mosquito Control District at 265-4453.