West Nile detected in Alhambra mosquito, Long Beach case

Health officials in Southern California are urging residents to protect themselves from mosquito bites after West Nile virus was detected in a mosquito in Alhambra and Long Beach reported its first human case.

For the third straight season, mosquito season in Southern California is carrying a sharper warning label.

Health authorities say West Nile virus has been detected in a mosquito caught in the San Gabriel Valley, and they’re doing it just as Long Beach reports its first human infection.

The latest alert came after the virus was found in a mosquito collected from a surveillance trap in Alhambra. a city in the San Gabriel Valley. The announcement was made Monday by the San Gabriel Valley Mosquito and Vector Control District. The district director of scientific programs. Tristan Hallum. said West Nile virus is “a recurring concern in our region because it is endemic to our area.”.

Long Beach’s case is the first human infection reported there last week. The Long Beach Department of Health and Human Services said the infected person was hospitalized with neuroinvasive illness. a condition that results in inflammation of the brain and surrounding tissues and can lead to permanent brain damage and even death. The person’s identity was not released. The department said the person is currently recovering at home.

Hallum said most infections are not fatal, but he emphasized that there is no cure or human vaccine for West Nile virus. “The key to staying safe and protecting your health is to prevent mosquito bites,” he said.

That message lands with urgency for residents because the risk is tied to the season itself. West Nile virus is common in the United States. and it’s particularly prevalent in California. where the mosquito species that can transmit the virus is native to Southern California. In the region. the southern house mosquito—known as culex quinquefasciatus—is described as the most common vector. according to the San Gabriel Valley Mosquito and Vector Control District. Officials say risk rises during hot weather, typically from June to October.

The biology of the virus doesn’t follow a neat pattern. The Centers for Disease Control and Prevention says about 4 out of 5 people infected with West Nile virus will have no symptoms and likely won’t realize they were infected. For the remaining 1 out of 5, mild symptoms usually begin 3 to 14 days after being bitten by an infected mosquito. Those mild symptoms include fever, headache, body aches, nausea, vomiting, and skin rash. While many symptoms improve on their own after a few days. fatigue and weakness can last for weeks or even months.

Severe disease, though less common, can be devastating. Less than 1% of those infected develop severe illness that affects the brain or nervous system. which can cause encephalitis or meningitis. according to the CDC. Severe symptoms include high fever, headache, neck stiffness, vision loss, numbness, confusion, muscle weakness, paralysis, and coma. Officials say these severe symptoms may last several weeks and can lead to permanent damage to the brain and nervous system. Each year in California. the CDC says people die from the virus. and about 1 out of 10 people who develop severe West Nile virus disease affecting the brain and nervous system die.

There’s also no specific treatment for the virus, officials said. In more severe cases, people may need hospital care for supportive treatment such as IV fluids, pain management, and nursing care.

The district says the virus was first recognized in the West Nile District of Uganda in 1937. It first appeared in the United States in New York in 1999. and the district said it was “most likely carried by an infected stowaway mosquito in a plane or cargo ship.” Within the following four years. it spread across the country alongside seasonal movement of infected birds. It arrived in the Los Angeles area in late 2003.

For residents, the current focus is practical—because the protection comes down to reducing mosquito exposure and keeping mosquitoes from breeding.

Officials say the best way to prevent infection is to stop mosquitoes from breeding around homes and avoid being bitten. They advise people to wear mosquito repellent on all exposed skin. The repellent should contain at least one of these active ingredients: DEET, IR3535, oil of Lemon Eucalyptus, or Picaridin/KBR 3023. They also recommend long-sleeved shirts and long pants when spending time outside during dawn and dusk. Removing stagnant water around the home—eliminating containers that catch and hold water—is another key step. Finally, they urge residents to install or repair door and window screens.

With a West Nile detection in an Alhambra mosquito and a confirmed human case in Long Beach, officials are essentially asking neighbors to treat the threat as real now—before a season that already tends to amplify risk from June to October has a chance to do more damage.

West Nile virus Alhambra mosquito Long Beach first case San Gabriel Valley Mosquito and Vector Control District Tristan Hallum neuroinvasive illness mosquito bite prevention