Epidemiology of smallpox,chickenpox,rubella and measles

describing the prevalence rate,mortality and morbidity data globally as well as in Indian scenario.

1. TOPICS: 1 . SMALL POX 2. CHICKEN POX 3.RUBELLA 4. MEASLES

2. SMALLPOX ( चेचक   , शीतला , बड़ी माता )

3. RESERVOIR Before global eradication, the only reservoir - humans . No natural reservoir for the virus currently exists. AGENT variola major or minor TRANSMISSION Inhalation of droplet or aerosols originating from the mouth of smallpox-infected humans Direct contact with skin lesions or infected body fluids of smallpox-infected humans Direct contact with contaminated clothing or bed linens EPIDEMIOLOGY

4. In the 18th century, British troops in North America gave smallpox infected blankets to their enemies, who went on to suffer severe outbreaks of smallpox. Russian scientists describe covert Russian operations during the 1970s and 1980s that focused on bioweapons research and development including creation of more virulent smallpox strains and development of missiles and bombs that could release smallpox SMALLPOX AS A BIOLOGICAL WEAPON

5. LAST CASE IN INDIA- 24 TH MAY,1975 ( SAIBAN BIBI, ASSAM) INDIA DECLARED FREE OF SMALLPOX- 5 TH JULY 1975 LAST CASE OF SMALLPOX in WORLD- OCT 26, 1977 MAY 8, 1980, OFFICIAL DECLARATION BY WHO - SMALLPOX ERADICATED! The End of Smallpox Last case of Variola minor, Somalia 1977 Last case of Variola major, Bangladesh 1975

6. CHICKENPOX( छोटी माता )

7. EPIDEMIOLOGY OCCURRENCE – both as endemic and epidemic RESERVOIR – human AGENT – varicella zoster TRANSMISSION person to person respiratory tract secretions direct contact with lesions TEMPORAL PATTERN In temperate areas-distinct seasonal fluctuation with the highest incidence occurring in winter and early spring . In the United States, incidence is highest between March and May lowest between September and November. Herpes zoster has no seasonal variation and occurs throughout the year.

8. GLOBAL STATUS Chickenpox led to about 105 deaths a year during the pre-vaccine years of 1990 to 1994 . Between 2002 and 2007 , the annual average number of chickenpox deaths was the lowest ever reported , with 14 deaths recorded in 2007 and just 13 the year before.  In 2006, a second dose was added to the vaccination roster which really eliminates casualties Chickenpox related deaths are now extremely rare.  

9. The CDC's new report from THE NATIONAL CENTER FOR IMMUNIZATION AND RESPIRATORY DISEASES , which updates an earlier analysis from 1995 to 2001, shows deaths have dropped by as much as 88 percent over the first 12 years in all age groups and by 97 percent in young people ( 20 and under), since the varicella  vaccine was introduced.

10. INDIAN STATUS OF CHCKEN POX In 2013- 28090 cases of chicken pox with 61 deaths Case fatality rate = 0.21% Kerala – highest (121168 cases) West bengal – max deaths

11. RUBELLA From Latin meaning “little red ” GERMAN MEASLES Discovered in 18th century t hought to be variant Of measles Togavirus RNA virus

12. EPIDEMIOLOGY OCCURRENCE - Rubella occurs worldwide RESERVOIR -human There is no known animal reservoir Transmission - spread from person to person via droplets shed from the respiratory secretions of infected persons. There is no evidence of insect transmission Temporal pattern - peak in late winter and spring

13. MEASLES ( खसरा ) morbilli , rubeola or red measles Paramyxovirus (RNA) Rapidly inactivated by - heat, sunlight, acidic pH, ether and trypsin Highly contagious viral illness First described in 7th century Near universal infection of childhood in prevaccination era Common and often fatal in developing countries

14. EPIDEMIOLOGY OCCURRENCE - Measles occurs throughout the world RESERVOIR -human There is no known animal reservoir, and an asymptomatic carrier state has not been documented. TRANSMISSION - respiratory Airborne via aerosolized droplet nuclei has been documented in closed areas (e.g., office, examination room) for up to 2 hours after a person with measles occupied the area. Temporal pattern - peak in late winter–spring Communicability -4 days before to 4 days after rash onset

15. In 2012, the World Health Assembly endorsed the Global Vaccine Action Plan* with the objective to eliminate measles in 4 World Health Organization (WHO) regions by 2015 & 2 regions by 2020. WHO Region Target Date for Measles Elimination Target Date for Rubella Elimination or Control African Region 2020 - Region of the Americas 2000 2010 South-East Asia Region 2020 2020 European Region 2015 2015 Eastern Mediterranean Region 2015 - Western Pacific Region 2015 2015

16. MEASLES 1993-2011 Endemic transmission interrupted Record low annual total in 2004 (37 total cases) Many cases among adults Most persons with measles were unvaccinated or unknown vaccination status In 2011, CDC reported 16 outbreaks of measles and 220 measles cases, most of which were imported cases in unvaccinated persons

17. GLOBAL STATUS OF MEASLES Estimates of measles-related deaths have been considered a crucial indicator to evaluate the progress of any nation towards measles elimination The global estimates for the year 2013 suggest that close to 0.14 million deaths were attributed to measles, accounting for nearly 16 deaths each hour   (Infection Ecology and Epidemiology 2015)

18. MEASLES STATUS IN INDIA More than one third of all measles deaths worldwide (around 56 000 in 2011) are among children in India . With support from WHO, in November 2010, India launched a massive polio-style measles vaccination project in 14 high-burden states, in a three-phase campaign. Health workers were trained to detect and report measles outbreaks, and they found an unexpectedly high number of infections.

19. INCREASING CHILD VACCINATION The government responded by establishing a system to ensure that every child who receives a first dose of the vaccine routinely gets a second. They also initiated ‘catch-up’ campaigns in areas where first-dose coverage was less than 80%. With two phases of the measles vaccination campaign completed, and the third phase ongoing, more than 102 million children in 344 districts have been vaccinated, achieving between 87% and 90% coverage .

20. Haryana: 22 Nov 2010 Rajasthan: 29 Nov 2010 Gujarat: 8 March 2011 Chhattisgarh: 14-15 Dec 2010 Madhya Pradesh: 6 Dec 2010 Bihar: 13 Dec 2010 Assam, Arunachel Pradesh: 8 Nov 2010 Phase 1 Calendar Of Catch-up Campaigns Jharkhand: 31 Jan 2011 Nagaland 7 Feb 2011 Uttar Pradesh: ??? Manipur: 29 Nov 2010 Tripura 31 Jan 2011 Meghalaya 7 March 2011 Bihar: 13 Dec 2010

21. While it is not yet possible to assess national impact, as the campaign is in different phases in different states, in some states the impact has been dramatic. Gujarat, for example, has gone from nearly 1000 cases in 2010 to none in 2012. In Bihar, once the state with the lowest immunization coverage levels in the country, the proportion of children immunized against common childhood diseases tripled as polio eradication activities intensified (from 18.6% in 2005 to 66.8% in 2010), underscoring the synergistic links between polio and measles efforts.

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