Summary about Disease
West Nile Fever is a viral infection primarily spread to humans through the bite of infected mosquitoes. Most people infected with West Nile virus do not develop any symptoms. However, about 20% of infected individuals will develop West Nile fever, a flu-like illness. In rare cases (less than 1%), the virus can cause a serious and potentially fatal neurological illness called West Nile encephalitis or meningitis.
Symptoms
No Symptoms: The majority of people infected (around 80%) have no symptoms.
West Nile Fever (Mild):
Fever
Headache
Body aches
Fatigue
Skin rash (occasionally)
Swollen lymph glands (occasionally)
Eye pain
West Nile Encephalitis/Meningitis (Severe):
High fever
Severe headache
Stiff neck
Disorientation
Tremors
Seizures
Paralysis
Coma
Causes
West Nile virus is the cause. The virus is primarily transmitted to humans through the bite of infected mosquitoes. Mosquitoes become infected when they feed on infected birds, which are the natural hosts of the virus. Less commonly, the virus can be spread through:
Blood transfusions and organ transplants (very rare, screening is conducted)
From mother to baby during pregnancy, delivery, or breastfeeding (rare)
Laboratory exposure (rare)
Medicine Used
There is no specific antiviral treatment for West Nile Fever. Treatment focuses on managing symptoms:
Mild Cases:
Pain relievers (over-the-counter, such as acetaminophen or ibuprofen) for fever and aches.
Rest
Hydration
Severe Cases (Encephalitis/Meningitis):
Hospitalization
Supportive care, including intravenous fluids, pain management, respiratory support (if needed), and prevention of secondary infections.
Is Communicable
West Nile Fever is not directly communicable from person to person through casual contact (e.g., touching, kissing, sharing utensils). Transmission occurs primarily through the bite of an infected mosquito. Very rare instances of transmission have occurred through blood transfusions, organ transplants, or from mother to baby.
Precautions
Mosquito Bite Prevention:
Use insect repellent containing DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), para-menthane-diol (PMD), or 2-undecanone. Follow the instructions on the repellent label.
Wear long-sleeved shirts and long pants when outdoors, especially during dawn and dusk, when mosquitoes are most active.
Install or repair screens on windows and doors to keep mosquitoes out.
Empty standing water from containers around your home (e.g., flowerpots, tires, bird baths, gutters) to prevent mosquito breeding.
Blood Donation:
If you have been diagnosed with West Nile Virus, inform the blood donation center.
How long does an outbreak last?
West Nile Virus outbreaks typically occur during the mosquito season, which generally runs from late spring through early fall (summer months). The length of an outbreak can vary depending on factors like weather conditions (temperature and rainfall, which influence mosquito populations) and mosquito control efforts. Outbreaks usually subside with the onset of colder weather and the decrease in mosquito activity.
How is it diagnosed?
West Nile Fever is diagnosed through laboratory tests:
Blood Tests: Detect antibodies to West Nile virus in the blood. IgM antibodies indicate a recent infection. IgG antibodies indicate a past infection.
Cerebrospinal Fluid (CSF) Test: If encephalitis or meningitis is suspected, a lumbar puncture (spinal tap) may be performed to collect CSF. The CSF is then tested for West Nile virus antibodies or the virus itself.
Urine Tests: Detect West Nile virus in urine.
Timeline of Symptoms
Incubation Period: 2 to 14 days after being bitten by an infected mosquito.
No Symptoms (80%): No noticeable symptoms.
West Nile Fever (Mild) (20%):
Symptoms typically develop 2-6 days after the incubation period.
Symptoms last for a few days to several weeks.
West Nile Encephalitis/Meningitis (Severe) (Less than 1%):
Symptoms typically develop within a similar timeframe as West Nile fever, but are more severe.
Recovery can take several weeks or months, and some neurological effects may be permanent.
Important Considerations
Risk Factors: People over the age of 50 and those with certain medical conditions (such as cancer, diabetes, hypertension, and kidney disease) are at higher risk of developing severe illness from West Nile virus.
Prevention is Key: Since there is no specific treatment for West Nile Fever, prevention of mosquito bites is the most important strategy.
Consult a Doctor: If you develop symptoms of West Nile Fever, especially if you experience severe headache, stiff neck, disorientation, or other neurological symptoms, seek medical attention immediately.
Long-Term Effects: Some people who recover from West Nile encephalitis or meningitis may experience long-term neurological problems, such as muscle weakness, fatigue, memory problems, and difficulty concentrating.