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Delaware Health Alert Network #223

April 19, 2010 7:07 pm

Health Alert


Delaware Division of Public Health (DPH) is investigating a report of five cases of varicella (chickenpox) among Delmar Middle / High School students. These five cases are confirmed on the basis of clinical compatibility and epidemiologic linkage to another confirmed or probable case.

Chickenpox is an infection caused by the varicella zoster virus. Chickenpox is still a relatively common infection, with most cases occurring in children up to age 10.


The best-known signs of chickenpox are a red, itchy rash that initially may look like insect bites, and small, liquid-filled blisters that break open and crust over. The rash may be preceded by or accompanied by fever, abdominal pain or loss of appetite, mild headache, general feeling of unease and discomfort (malaise) or irritability, a dry cough and/or a headache. Common sites for the rash include the face, scalp, chest and back. The rash can also spread across the entire body. New spots continue to appear for several days.

In healthy children, the disease is generally mild. Certain groups of people are more likely to have more severe illness with serious complications. These include adults, infants, adolescents, and people whose immune systems have been weakened because of illness or medications such as long-term use of steroids. Serious complications from chickenpox include bacterial infections that can involve many sites of the body including the skin, tissues under the skin, bone, lungs (pneumonia), joints, and blood. Other serious complications are due directly to infection with the varicella-zoster virus and include viral pneumonia, bleeding problems, and infection of the brain (encephalitis).

About 15%–20% of people who have received one dose of chickenpox vaccine do still get chickenpox if they are exposed, but their disease is usually mild. Vaccinated persons who get chickenpox generally have fewer than 50 spots or bumps, which may resemble bug bites more than typical, fluid-filled chickenpox blisters.


Transmission is person-to-person by direct contact, droplet or airborne spread of vesicle fluid or secretions of the respiratory tract. Transmission may also occur by indirect contact with articles freshly soiled by discharges from vesicles and mucus membranes of infected people. A person with chickenpox is contagious 1-2 days before the rash appears and until all blisters have formed scabs. It takes from 10-21 days after exposure for someone to develop chickenpox.

Incubation period:

2 to 3 weeks, commonly 14-16 days.

Prevention and Control:

  1. Exclude children from school, medical offices, emergency rooms, or public places until vesicles become dry, usually after 5 days in unimmunized children and 1-4 days with breakthrough varicella in immunized children.
  2. Exclude infected adults from workplace and avoid contact with susceptible immunocompromised patients.
  3. Disinfect articles soiled by discharges from the nose and throat.
  4. Quarantine is usually not necessary.
  5. Varicella vaccine is effective in preventing illness or modifying severity if used within 3 days and possibly up to 5 days of exposure; it is recommended for susceptible persons following exposure to varicella.
  6. Varicella zoster IG may be indicated for newborns of mothers who develop chickenpox within 5 days prior to or within 2 days after delivery, and for persons ineligible for immunization (such as susceptible pregnant females and those at high risk for severe disease).
  7. Antiviral drugs appear useful in preventing or modifying varicella in exposed individuals if given within a week of exposure.

Please note that DPH has advised Delmar school officials to advise parents that because this is an outbreak, they should contact their healthcare provider about getting a second dose of varicella vaccine if their child has received only one dose.


In otherwise healthy children, chickenpox typically requires no medical treatment. An antihistamine may be helpful to relieve itching. Antiviral agents may of illness help shorten the duration. Aspirin should never be given to children with chickenpox who are less than 19 years of age, because it can result in Reye syndrome.

To Report Cases

Medical practitioners are reminded that chickenpox is a notifiable disease in Delaware; cases of chickenpox should be reported to the DPH within 48 hours. Reporting specifics and forms are available at: Reports can also be called into the DPH Bureau of Epidemiology by calling (302) 744-1033 or 1-888-295-5156.

More Information:

More information on chickenpox is available from:


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