Chickenpox and Smallpox.PSM,COMMUNITY MEDICINE,DR NARENDRA KUMAR YADAV,DR NARENDRA KUMAR YADAV

Chickenpox and Smallpox,DR NARENDRA KUMAR YADAV,DR NARENDRA KUMAR YADAV

1. Chickenpox and Smallpox DR NARENDRA KUMAR YADAV MBBS, MD Community Medicine & Tropical Diseases

2. Case-Scenario: Q. During the month of January 2018, 15 children from the local brick factories attended at Hospital with complain of mild grade fever, cough and skin rashes. The attending pediatrician clinically diagnosed as chicken pox(Varicella). Only five children got full vaccination according to national EPI. Describe epidemiology of chicken pox. What is pathognomonic sign of chicken pox? List the vaccines included in the national EPI program. Discuss the prevention and control of Varicella.

3. Chickenpox: .

4. Smallpox:

5. Chickenpox and Smallpox:

6. CHICKENPOX (Varicella ) : Chickenpox (varicella) is an acute, highly infectious disease caused by varicella-zoster (V-Z) virus . Only one serotype of VZV is known. One attack results in life-long immunity; second attacks are rare.

7. Epidemiology of Chickenpox: Chickenpox occurs in all parts of the world. Chickenpox can affect anyone but more common in Children under 10 years. WHO: In 2013, there were 140 million cases of chickenpox and shingles worldwide. World (WHO): In 1990: 8,900 deaths In 2013: 7,000 deaths In 2015: 6,400 deaths Death occurs in about 1 per 60,000 cases

8. Epidemiological determinants of Chickenpox: Agent factors Host factors Environmental factors Varicella Zoster(HHV3) SOURCE OF INFECTION: Cases. Age group: Any age but more common in Children under 10 years. PREGNANCY: Congenital Varicella Syndrome. Any season but more common in Winter and Spring.

9. Chickenpox: Incubation period : 14-16 days. Mode of transmission : 1. Respiratory disease , transmitted mainly by Air droplets. 2. V esicular fluid 3. Vertical transmission Period of communicability: 2 days- Rash - 5 days SAR: > 90%

10. Clinical features of Chickenpox: 1. PRE-ERUPTIVE STAGE: 2. ERUPTIVE STAGE: Fever (Mild/moderate) Back pain Malaise Rash comes on the day the fever starts. Rash first appears on the trunk. Rash is Centripetal in distribution Rash is Pleomorphic Rash is symmetrical Palm and soles are spared. Sign of inflammation is seen around the rash “ DEW DROP ON ROSE PETAL ” appearance . Scabs form 4-7 days after the rash appears.

11. Chickenpox:

12. CHICKENPOX

13. Differences between smallpox and chickenpox rash: Chickenpox rash: Smallpox rash: Rash first appears on the trunk. Rash is Centripetal in distribution Rash is Pleomorphic Area of inflammation is seen around the rash “ DEW DROP ON ROSE PETAL ” appearance. Palm and soles are spared. Axilla affected. Rash is superficial and Unilocular Rash commonly seen in Flexor surface Rapid Evolution Scabs form 4-7 days after the rash appears. Rash first appears on the face. Rash is Centrifugal in distribution Only one stage of rash is seen at one time(non-pleomorphic). NO area of inflammation is seen around the rash Palm and soles involved. Axilla usually free. Rash is deep-seated and Multilocular Rash commonly seen in Extensor surface Slow Evolution Scabs form 10-14 days after the rash appears.

14. Diagnosis: Diagnosis of chicken pox is based on Typical rash of chicken pox. Microscopic examination of vesicular fluid: Detection of VZV DNA using PCR. IgM-antibodies

15. Complications of chicken pox: M/C Complications: VARICELLA Pneumonia M/C Late Complications: Shingles (Due to reactivation of HZV in 10-30%) Following infection, the virus remains latent in neural ganglia and in about 10-20% of cases it is reactivated to cause shingles or herpes zoster. Shingles Shingles

16. Shingles or herpes zoster:

17. Prevention and control of Varicella: Active immunization: A live attenuated varicella virus vaccine Passive immunization: Immunoglobulin (12.5 U/kg) is given 72 hours of exposure. Isolation: Cases should be isolated Health Education, Information and Communication

18. Varicella virus vaccine: Types: Live attenuated Strain: Oka VZV strain Age of administration: Age between 12 months and 12 years Dose of administration: 0.5 ml ( 2 dose) Route of administration: SUBCUTANEOUS (S/C)

19. Treatment of Chicken Pox: Acyclovir Paracetamol Antihistamines Calamine Lotion

20. Small Pox (VARIOLA): An acute infectious disease caused by Variola virus. Incubation period: 12 days SAR: 30-40% Mode of transmission: Respiratory disease transmitted mainly by Air droplets. Previously, it was one of the greatest killer disease. Eradication (WHO): 8 May 1980

21. Centripetal Rash vs Centrifugal Rash: Centripetal Rash: Lesions concentrated on the center of the body(Trunk), fewer lesions on the extremities. Ex: Chicken Pox Centrifugal Rash: Lesions concentrated on the face and extremities; fewer lesions on the trunk. Ex: Small Pox

22.   Pleomorphism: A characteristic feature of the rash in chickenpox is its pleomorphism. Pleomorphism: All stages of the rash (macules, papules, vesicles and crusts) is seen simultaneously at  one time, in the same area.

23. Q. Write the differences between Chickenpox and Smallpox.

24. MCQ Q. Chickenpox is infective: 2 days before and 2 days after rash appearance 2 days before and 5 days after rash appearance 4 days before and 4 days after rash appearance 4 days before and 5 days after rash appearance

25. Ans: b ( 2 days before and 5 days after rash appearance)

26. MCQ Q. Secondary attack rate (SAR) of chickenpox is: 60 50 40 90

27. Ans: d (90)

28. MCQ Q. Chickenpox is characterized by all except: a. Scabs are infective b. Pleomorphic rash c. Rashes symmetrical centripetal dew drop like d. Palms and soles not affected by rash

29. Ans: a (Scabs are infective)

30. MCQ Q. All of the following are true about Varicella virus except: 10-30% chance of occurrence All stages of rash are seen at the same time Secondary attack rate is 90% Rash commonly seen in flexor area

31. Ans: a (10-30% chance of occurrence) Single attack of Varicella gives durable(lifelong) immunity.

32. MCQ Q. All are true about chickenpox except: a. Crusts contain live virus b. Centripetal in distribution c. Pleomorphic rashes seen d. Rapid progression from macule to vesicle

33. Ans: a (Crusts contain live virus)

34. MCQ Q. Smallpox eradication was successful due to all of the following reasons except: Subclinical cases did not transmit the disease A highly effective vaccine was available Infection provide lifelong immunity Cross resistance existed with animal pox.

35. Ans: d ( Cross resistance existed with animal pox). No known animal reservoir was seen.