West Nile Virus Detected Early in Calgary Mosquitoes as Health Experts Urge Residents to Take Precautions

Health experts are urging Calgarians to protect themselves from mosquito bites after West Nile virus was detected in mosquitoes earlier than usual this year, raising concerns that the risk of human exposure could be higher during the remainder of the summer.

Researchers from the University of Calgary, working in partnership with the City of Calgary, have confirmed that mosquitoes carrying West Nile virus were first identified in late June. The virus has continued to be detected in mosquito samples collected throughout July, making it the earliest confirmed detection in the city in recent years.

Scientists monitor mosquito activity using traps located at several sites across Calgary and one location outside the city. The surveillance program helps identify the presence of mosquito-borne diseases and provides an early warning for public health officials.

According to researchers, the virus appears to be circulating more widely among Calgary’s mosquito population this summer than in previous years. While improved monitoring methods may also contribute to increased detection, experts say the findings indicate that the virus is now established within local bird populations, which serve as the primary hosts before infected mosquitoes transmit the virus to humans.

Health officials say the discovery does not mean an outbreak is underway, but it does increase the importance of taking preventive measures, particularly during the peak mosquito season.

Primary Care Alberta has also confirmed that one travel-related case of West Nile virus has been reported in the province so far this year. No locally acquired human infections have been confirmed in Calgary at this time.

West Nile virus is spread through the bite of an infected mosquito and cannot be transmitted directly from person to person through casual contact.

Most people infected with the virus experience no symptoms at all. Health experts estimate that approximately 80 per cent of infected individuals remain symptom-free throughout the course of the illness.

Those who do develop symptoms may experience fever, headache, body aches, fatigue, swollen lymph nodes and a mild skin rash. Symptoms usually appear between two and fifteen days after an infected mosquito bite.

Although most cases remain mild, the virus can cause serious complications in a small number of people, particularly older adults over the age of 50 and individuals with weakened immune systems.

In severe cases, West Nile virus can affect the brain and nervous system, leading to conditions such as meningitis or encephalitis. Symptoms requiring immediate medical attention include severe headache, high fever, stiff neck, confusion, tremors, muscle weakness, paralysis, seizures or loss of consciousness.

Health officials emphasize that early medical evaluation is important if these symptoms develop following mosquito exposure.

Researchers believe this year’s higher mosquito activity is linked to wetter-than-normal weather earlier in the summer, which created ideal breeding conditions across Calgary. Standing water left behind after periods of rain provides mosquitoes with suitable places to lay eggs, allowing populations to increase rapidly.

The mosquitoes found carrying the virus belong to the northern house mosquito species, also known as Culex pipiens. This species is considered one of the primary carriers of West Nile virus and is most active during dawn and dusk, when the risk of mosquito bites is greatest.

Public health officials are encouraging residents to take simple but effective precautions to reduce the risk of infection throughout the summer.

Using insect repellents containing DEET remains one of the most effective methods of preventing mosquito bites. Products containing oil of lemon eucalyptus can also provide protection for many adults. Officials note that DEET should not be used on infants and should only be applied carefully on young children according to product directions.

Residents are also advised to wear loose-fitting clothing with long sleeves and long pants when spending time outdoors, particularly during the early morning and evening hours when mosquitoes are most active.

Eliminating standing water around homes is another important preventive measure. Buckets, bird baths, flower pots, clogged gutters, old tires and other containers that collect water can become mosquito breeding sites if left untreated.

Health authorities say community awareness and personal protection remain the best defence against West Nile virus. By reducing mosquito breeding areas and taking precautions against bites, Calgarians can significantly lower their risk of infection while continuing to enjoy outdoor activities during the summer months.

With mosquito populations expected to remain active through the warm season, officials encourage residents to stay informed, follow public health recommendations and seek medical advice if they develop symptoms consistent with West Nile virus after being bitten by mosquitoes.

Courtesy: CBC