Public health officials in Montana are reporting the season’s first West Nile Virus (WNV) detections with both mosquito samples and humans testing positive for infection.
According to a press release from the Montana Department of Public Health & Human Services, three human cases have been reported in McCone, Bighorn, and Toole counties, and mosquito samples from Blaine, Hill, Custer and Prairie counties recently tested positive.
The human cases, all adults, experienced mild symptoms and did not require hospitalization.
“With the hot conditions experienced in July we see mosquitoes carrying WNV emerge,” said DPHHS Director Sheila Hogan. “We usually see positive mosquito samples followed by human cases. This year we are seeing both at the same time and it is a reminder to avoid mosquito bites.”
Most people who become infected with WNV experience no symptoms but 1 in 5 develop a mild illness, called West Nile fever, which may last for three to six days. Other individuals, fewer than 1 out of 150, may become severely ill with encephalitis or meningitis (inflammation of the brain or surrounding tissues). Recovery from severe disease may take several weeks or months. Some of the neurologic effects may be permanent and about 10 percent of people who develop neurologic infection will die.
There is no available treatment for WNV infection other than supportive care. Individuals who develop any of these symptoms should see their healthcare provider. These first reported cases illustrate that WNV is a real threat and people need to take action to protect themselves.
DPHHS reminds Montanans to take precautions and protect against WNV by following the 5 Ds of WNV prevention. The 5 Ds include:
For more information about WNV protection, contact your local health department or click here.
The federal Centers For Disease Control & Prevention provides the following information:
No symptoms in most people. Most people (8 out of 10) infected with West Nile virus do not develop any symptoms.
Febrile illness (fever) in some people. About 1 in 5 people who are infected develop a fever with other symptoms such as headache, body aches, joint pains, vomiting, diarrhea, or rash. Most people with this type of West Nile virus disease recover completely, but fatigue and weakness can last for weeks or months.
Serious symptoms in a few people. About 1 in 150 people who are infected develop a severe illness affecting the central nervous system such as encephalitis (inflammation of the brain) or meningitis (inflammation of the membranes that surround the brain and spinal cord).
Symptoms of severe illness include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis.
Severe illness can occur in people of any age; however, people over 60 years of age are at greater risk. People with certain medical conditions, such as cancer, diabetes, hypertension, kidney disease, and people who have received organ transplants, are also at greater risk.
Recovery from severe illness might take several weeks or months. Some effects to the central nervous system might be permanent.
About 1 out of 10 people who develop severe illness affecting the central nervous system die.