Health Alerts > 8/11/10 West Nile virus and Dengue fever

Date:  August 11, 2010

Topic:  H1N1 and Arboviral disease

H1N1

Good news, the WHO has declared the H1N1 pandemic officially over.  Furthermore, the current seasonal flu vaccine does contain protection against H1N1.

Thanks again to all of you who made the H1N1 pandemic seem relatively minor to the public.  But we know how hard you all worked to see the excess patients in offices, urgent care centers and ERs.  We also appreciate your help in vaccinating as many people as possible.  Great job!

Arboviral Disease:
West Nile virus (WNV):

We are seeing a lot of WNV activity in our mosquito population this year – so be on the lookout for potential cases.

Epi:  peak incidence is late August through early November.

Morbidity/Mortality:

Twenty percent of people infected will develop WNV fever.  Less than 1% of persons who are infected with the West Nile virus develop severe illness; of individuals who have severe illness secondary to the infection, 3-15% die.

Severe disease particularly affects the elderly, especially persons older than 75 years.

Symptoms: of WNV fever:

• Fever
• Headache
• Fatigue
• Skin rash on the trunk of the body (occasionally)
• Swollen lymph glands (occasionally)
• Eye pain (occasionally)

Symptoms of WNV neuroinvasive disease:

• Fever
• Gastrointestinal symptoms
• Ataxia and extrapyramidal signs, Myelitis, Polyradiculitis, Flaccid paralysis is sometimes seen or Optic neuritis
• Seizures
• Weakness
• Change in mental status
• Some with severe disease develop a maculopapular or morbilliform rash involving the neck, trunk, arms, or legs.
• Although not observed in recent outbreaks, myocarditis, pancreatitis, and fulminant hepatitis have been described. West Nile poliomyelitis, a flaccid paralysis syndrome, is less common than meningitis or encephalitis

Diagnosis

For children less than 16 years of age, please consider La Crosse encephalitis as well.  West Nile (IgG and IgM) and LaCrosse (IgG and IgM) can be ordered separately or together

Dengue Fever:

Dengue Fever affects 100 million people worldwide every year. According to the NIH; for the first time in 75 years, Dengue has reappeared in parts of Florida and dozens of cases have already been reported this year. So far, cases have been reported primarily in the South Florida area thought to be evolving from the Caribbean Dengue Epidemic. Please remind your patients going to Florida to take measures to protect themselves by using mosquito repellant WHENEVER THEY ARE OUTSIDE.  Also, consider the diagnosis of Dengue if a patient has recently returned from a visit to Florida or has been volunteering in Haiti or any country in the Caribbean.

The incubation period is 4 to 7 days

Symptoms include:

High fever, severe headache, severe pain behind the eyes, joint pain, muscle and bone pain, rash, and mild bleeding (e.g., nose or gums bleed, easy bruising). Generally, younger children and those with their first dengue infection have a milder illness than older children and adults.

Diagnosis:

This is also a serological test for IgG and IgM to Dengue fever virus.

Questions call Deb McMahan, MD