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Sir Edward Jenner
Definition • Acute infectious disease caused by variola virus and clinically characterised by sudden onset of fever,backache,headache,vomiting,and sometimes convulsions,esp in children .on third day of fever ,a typical rash appear which is centrifugal in distribution and passes through successive stage of macule,papule,vesical pastule and scab with subsequent scaring.
SMALL - POX • VARIOLA (ICD-10): B03 • Variola :- Orthopox Virus • Large DNA virus • Types- Major Minor
5 subtypes- • Modified Sp (15%) Abortive attack • Haemorrhagic Sp (2.7%)- • Early : Purpura Variolas • Late : Variola pustulosa H’gica • Flat type (0.3%) • Variola sine eruption (v. rare)
VARIOLA Major • CFR 20% to 50% • Classical Small pox (82%) • VARIOLA Minor -Milder form -Short duration -Mistaken for chickenpox -Mortality <1%
Host: all age groups Occupation: Medical & Nursing Physiological: Pregnancy & immuno-compromised Host Factors
Immunity: life long after infection Secondary sub-clinical cases were common -They do not transmit infection, Only booster the immunity Immunity
Source : Case of Sm. Pox, • No carrier, • Reservoir : NONE • Infectivity: Untill the scab is formed Max. during 1st week of of Rash • S.A.R. = 35-40%
Environmental Factors • Low temperature & High Humidity Virus survival increased • Season: Winter & Spring • Ventilation: Overcrowding Spread
Modes of Transmission • Direct: Implantation on Nasal, Oropharyngel, Mucous membrane Secretion from the rash \scab • Indirect: Air borne, Fomite borne, Close contact with patients, or their clothing or bedding, is thus required for infection.
Incubation Period • 10 days -17 days • (average - 12days ) rarely 7-17 days
Signs &Symptoms • Fever , Backache, Malaise, Headache, Convulsions in children , Delirium • Abdominal Colic in adults • A rash appears after 2 to 4 days and progresses through characteristic stages of papules, vesicles, pustules and finally scabs. • Scabes fall off at the end of 3rd or 4th week
Centrifugal distribution Most dense • On face & extremities than on trunk • Distal part of limbs than proximal, • Extensor surface • Convexities,
The density of the rash is greater on the face than on the body.
Day-1 • few raised spots called papules appear. • Usually seen first on the face, and later on the body and extremities.
Day-2 more papules appear.
By day 3 • the rash has become more distinct and raised above the skin surface. • Fluid is accumulating in the papules to form vesicles.
day 4, • the vesicles are more distinct , they feel very firm to the touch. • When broken, they do not collapse because the fluid is contained in many small compartments.
By day 5, • the fluid in the vesicles has become cloudy and looks like pus. • At this time, the fever usually rises and the patient feels more ill than before.
On day 7 • The rash is definitely pustular. • Umbilication starts • Although varying somewhat in size, all resemble each other in appearance.
Day 8 and 9 • the pustules increase somewhat in size. • They are firm to the touch and deeply embedded in the skin.
Day 10-14 • The scabs begin to appear • The scabs contain live smallpox virus. • Until all scabs have fallen off, the patient may infect others.
By day 20, • the scabs have come off and light-coloured or depigmented areas are observed. • Non infectious stage
Over a period of many weeks the skin gradually returns to its normal appearance. • Scars which last for life may remain on the face, an indication of previous infection with smallpox.
3 4 5 13 7 9 Papules Vesicles Pustules Scabs
FEVER – 4 – 3 – 2 – 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 21 Days Pre-eruption Papules Pustules Scabs RASH Onset of rash
Complications • Pustules- secondary Infection • Ocular • Bones & joints • Resp.-Pneumonia • Bronchitis, Pulm. Oedema • G.I. syst- Diarrhoea, Ac. Dilatation of Stomach, Infection of Intestine • GU sys- Orchitis • CNS- Encephalitis
Diagnosis • Clinical- & Lab : • Skin scab. Oro-pharyngeal, • Mucous membrane • Conjunctiva, • Urine
The eradication campaign was based on two key strategies: • (1) mass vaccination and • (2) the detection and containment of all cases of smallpox. • Surveillance: Facial Pocks marks survey Rumor register
Prevention & Control • Isolation & Quarantine were used in early days • Vaccination: • Early days: Variolation • Edward Jenner (1796) - 1st Vaccination using Cow Pox • Surveillance: Facial Pocks marks survey • Rumor register
Sir Edward Jenner18th century • People who survived from small pox (S.P) did not get disease again--- Life long immunity. • Variolation- To infect healthy individual with s.p. material taken from the pustules of infected individual Some were developing the ds. Or developed other infection
Small pox epidemic Developed Did not developed disease disease Milkmaid women had contact Cow pox Hypothesis- Cow pox offers immunity to S.Pox.
Administration of Cow pox material to 8 yrs. Old healthy volunteer After 6 weeks Inoculated from small pox pustules No disease Large no. of people Results Immunization schedule Evaluation of the effect & coverage Eradication Of Small pox Vaccination
Vaccination • Dryvax was created in the late 1800s, by the company that became Wyeth Laboratories
Administration- by making 15 punctures in the skin with a special needle. Revaccinationrecommended at least every 10 years.
Vaccination • Wyeth stopped making the vaccine in the 1980s. But government officials kept a stockpile of about 15 million doses. • The Dryvax came in handy in 2003, when it was used to help contain an outbreak of monkeypox in the United States.
