Chicken pox

CHICKEN POX
highly contagious viral infection which causes an itchy, blister-like rash on the skin.
Chickenpox is highly contagious to those who haven't had the disease or been vaccinated against it.
The most characteristic symptom is an itchy, blister-like rash on the skin.
Chickenpox can be prevented by a vaccine. Treatment usually involves relieving symptoms, although high-risk groups may receive antiviral medication.

1. Varicella Chicken pox Vd Rakesh Shukla Lecturer, Dept of Swasthavritta GAAC, Ahmedabad Vd Rakesh Shukla, Lecturer, GAAC, Ahmedabad

2. Chicken pox or varicella is an acute, highly infectious disease caused by varicella-zoster (V-Z) virus . It is characterized by vesicular rash that may be accompanied by fever and malaise. Chicken pox and herpes are now regarded as different host response to the same aetiological agent. Vd Rakesh Shukla, Lecturer, GAAC, Ahmedabad

3. Epidemiological determinants 1. Agent factors: V-Z virus is also called as “human (alpha) herpes virus. 2) Source of infection: usually a case of chicken pox. The virus occurs in the oropharyngeal secretions and lesion of the skin and mucosa. Rarely the source of infection may be herpes zoster. The virus can be readily isolated from the vesicular fluid during the 1 st , 3 days of illness. The scabs however are not infected Vd Rakesh Shukla, Lecturer, GAAC, Ahmedabad

4. 3) Infectivity: estimated to be 1-2 days before the appearance of the rash, and 4-5 days there after. The virus tends to die out before the pustular stage. 4) Secondary attack rate – highly communicable, 90% secondary attack rate . Vd Rakesh Shukla, Lecturer, GAAC, Ahmedabad

5. Recovery from primary infection is commonly followed by the establishment of latent infection in the cranial nerves sensory ganglia and spinal dorsal root ganglia, often for decades, with out clinical manifestations. It is a painful, vesicular, pustular eruptions in the distribution of 1 or more sensory nerve roots. This virus can be grown in tissue culture. Vd Rakesh Shukla, Lecturer, GAAC, Ahmedabad

6. Host factors Age : among children under age of 10 years. Immunity: one attack gives durable immunity; second attacks are rare. maternal antibody protects the infant during the 1 st few months of life. The IgG antibodies persists for life and their presence is correlated with the protection against varicella. Pregnancy: infection during pregnancy presents a risk for the foetus and neonate. Vd Rakesh Shukla, Lecturer, GAAC, Ahmedabad

7. 5) Environmental factors: Chicken pox shows a seasonal trend in India, the disease occurring mostly during the 1 st 6 months of the year. Over crowding favors its transmission 6) Transmission : person to person by droplet infection and droplet nuclei. Most of them are infected by face to face (personal contact). 7) The portal of entry of the virus is the respiratory tract. The virus can cross the placental barrier and infect the foetus , a condition known as congenital varicella. Vd Rakesh Shukla, Lecturer, GAAC, Ahmedabad

8. 8) Incubation period: 14-16 days, although extremes as wide as 10-21 days. 9) Clinical features: may vary form mild illness with only a few scattered lesions to a severe febrile illness with wide spread rash. In majority of cases the disease tend to be mild and typical Vd Rakesh Shukla, Lecturer, GAAC, Ahmedabad

9. 2 stages Pre- eruptive stage: onset is sudden with mild or moderate fever, pain in back, shivering and malaise lasting for 24 hours. In adults, the prodromal illness is usually more severe and may last for 2-3 days. Vd Rakesh Shukla, Lecturer, GAAC, Ahmedabad

10. II) Eruptive stage: In children rash is often the 1 st sign. It comes on the day the fever starts. The distinctive features are Distribution: rash is symmetrical . 1 st appears on the trunk where it is abundant, then face, arms and legs where it is less abundant. Mucosal surface are generally involved. The density of the eruption diminishes centrifugally . Rapid evolution : rash advances quickly through the stages of macule, papule, vesicle, scab . dew drops on skin is the 1 st appearance. Scabbing begins 4-7 days after the rash appears . Vd Rakesh Shukla, Lecturer, GAAC, Ahmedabad

11. c) Pleomorphism : that is all stages of the rash (papules, vesicles and crusts may be seen simultaneously at 1 time at the same area. d) fever: the fever does not run high but shows exacerbations with each fresh crop of eruption. Complications Hemorrhages, pneumonia, encephalitis, acute cerebellar ataxia, reye’s syndrome, cutaneous scars, atrophies limbs, microcephaly, LBW, micropthalmia , chorioretinitis , deafness, cerebro - cortical atrophy Vd Rakesh Shukla, Lecturer, GAAC, Ahmedabad

12. Laboratory diagnosis: Not required where clinical signs are usually clear cut. Examination of the vesicle fluid under electron microscope – shows round particles(brick shaped in small pox) Control: – N otifications I solations of cases for about 6 days after the onset of rash and disinfection of articles soiled by nose and throat discharges. Prevention – Varicella Zoster Immunoglobin (VZIG) – given with in 72 hours of exposure. IM dose 12.5 units/kg body weight upto max of 625 units with a repeat dose in 3 weeks. Vaccine – a live attenuated varicella virus vaccine is safe for children between 12-18 months. Vd Rakesh Shukla, Lecturer, GAAC, Ahmedabad

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