1. Chickenpox (varicella)
Sarah Fisher

2. What is Chickenpox?
Highly contagious disease caused by Varicella Zoster Virus (VZV)
On of the most commonly contracted childhood diseases
Usually mild and not life-threatening to otherwise healthy patients
Potentially severe in infants, adults and others with impaired immune systems
Infections cause long-term immunity—second infections are rare

3. History
1500s: Believed to have been first discovered by Giovanni Fillipo in Italy
1600s: English physician Richard Morton gave the disease the name “chickenpox” because he believed it was a milder version of smallpox
1700s: English physician William Heberden became the first physician to prove that chickenpox and smallpox were two different diseases

4. History Cont.
1888: Relationship between Herpes Zoster and chickenpox was suggested
1986: Complete DNA sequence of VZV was established
1995: FDA approved vaccine to immunize children and other susceptible individuals against chickenpox

5. Transmission One of the most readily transmissible diseases
Can be spread from person to person by:
Direct contact with fluid from the blisters
Direct contact with secretions from the respiratory tract
Handling an infected person’s clothing or bedding
Exposure to the coughing or sneezing of an infected person (airborne)
Touching or breathing in the virus particles that come from chickenpox blisters
Susceptibility is universal among those not previously infected
Greatest number of cases occur in the winter/early spring

6. Symptoms Symptoms usually start about two weeks after exposure
Fever, tiredness, loss of appetite, headache, an itchy rash
Rash generally starts as little red spots on the chest, stomach or back and then spreads to the face
Infected patient may only get a few spots, a large cluster or develop hundreds of spots during the first 3-5 days of the rash
Spots turn into clear, fluid-filled blisters and eventually turn to scabs (2-4 days)
Very contagious 1-2 days before rash appears and until all blisters have formed scabs

7. Complications Not common in otherwise healthy people
People with more severe risks for complications:
Infants
Adolescents
Adults
Pregnant women
People with weakened immune systems because of illness or medications
1/400 patients need hospitalization
Approx. 90 deaths/year

8. Complications Cont. Serious complications include:
Dehydration
Pneumonia
Bleeding problems
Brain infection/inflammation
Bacterial infects of the skin/soft tissues
Blood stream infections (Sepsis)
Toxic shock syndrome
Bone infections
Joint infections
Chickenpox remains latent and may recur years later as Herpes Zoster (shingles)
Risk increases with age and for those with HIV

9. Prevention
The best way to prevent the disease is to get vaccinated—98% percent effective
Children, adolescents and adults should have two doses
With the vaccine, it is still possible to contract the disease but it will be much more mild with fewer blisters and a mild or no fever
Vaccine is required for attendance in day care and schools

10. Prevention Cont.
If you have never had chickenpox, vaccinated or not, you should stay away from any infected people
Some newborn babies, any immune-deficient child and any susceptible persons over 14 years of age who have not been previously vaccinated may need a shot of varicella zoster immune globulin (VZIG) to try and prevent chickenpox contraction after exposure

11. Treatment Acetaminophen can be given to reduce fever
Aspirin should not be given because it may cause Reye syndrome
Calamine lotion, antihistamines and oatmeal baths can be given to help reduce itching
Acyclovir is a new drug now given to some patients within the first day after rash onset to make the symptoms milder

12. Epidemiology Varicella is endemic in the US with seasonal fluctuation
Between 150, ,000 cases are reported annually to the CDC (1998)
Highest attack rates are in children ages 509—60% of all cases

13. Epidemiology Cont.
By adulthood, 90-95% of the US population have antibodies to varicella
In the tropics, varicella occurs more often in adults so immigrants from these areas are more likely to be susceptible than the rest of the population at comparable ages

14. Herpes Zoster (Shingles)
Reactivation of latent varicella zoster virus (VZV)
Associated with aging, immunosuppression, in-utero exposure to varicella, and postnatal varicella (before 18 months)
In the immunocompromised, zoster can disseminate, causing generalized skin lesions, and central nervous system (CNS), pulmonary, and hepatic involvement

15. Sources