Vol. 17, No. 1	March 1996

Following an outbreak of 17 cases of smallpox in Penha, Rio de Janeiro, then State of Guanabara, Brazil, from 22 December 1970 to 6 March 1971, two more cases have occurred in patients who were infected with smallpox while hospitalized for pemphigus. Because of their dermatosis, neither of these patients was vaccinated against smallpox. On 2 March 1971, two children in the eruptive phase of smallpox were admitted to the Eduardo Rabelo Hospital in Rio de Janeiro, occupying a room adjoining the ward for skin diseases where both pemphigus patients were hospitalized. The first of the two secondary cases was a 28 year old male admitted to the hospital on 12 February; he began to have fever on 23 March and rash on 27 March. The second patient, an 18 year old male, was admitted on 11 March and presented symptoms of smallpox on 19 April. This was the last case of smallpox in the Americas.

The last countries to report cases in the Region of the Americas were: Brazil, which had reported casessince 1920 and for the years 1968 to 1971 reported 4372, 7407, 1771 and 19 cases, respectively; Argentina, which reported 24 cases in 1970; Uruguay, which reported 3 cases in 1969; and French Guiana, which reported one case in 1968.

Smallpox, described by the historian Macaulay as "the most terrible of all the ministers of death", has been a scourge of mankind since ancient times. Repeated epidemics have across the world, decimating populations and altering the course of history. Not until Jenner demonstrated, exactly 200 years ago, in 1796, that inoculation with cowpox would protect against smallpox was there hope that the disease could be controlled.

The World Health Assembly, from the time of its first meeting in 1948, expressed increasing concern about smallpox. In 1958 it reviewed the question of the eradication of smallpox from the world and in 1959 recommended that smallpox-endemic countries should launch special programs for that purpose. A number of countries became smallpox-free in the following years, but in the major endemic areas of Africa, Brazil and South-East Asia, little progress towards eradication had been made. In 1966, the Nineteenth World Health Assembly decided that an intensified program was necessary, financed from the regular budget of the Organization, and it requested countries, multilateral and bilateral agencies to provide additional assistance.

he intensified program called for the vaccination of at least 80% of the population within a period of two or three years, during which time reporting systems and surveillance activities would be developed that would permit detection and elimination of the remaining foci of the disease.

Progress was slow in some countries but rapid in others. The countries of west and central Africa became smallpox-free in 1970, Brazil in 1971, Indonesia in 1972, and the countries in eastern and southern Africa in 1973. Major campaigns by the countries of the Indian subcontinent achieved eradication there between 1973 and 1975. Finally, in the Horn of Africa, Ethiopia became smallpox-free in 1976 and Somalia in 1977.

The eradication of smallpox in the Americas and in the world has left several positive elements such as the development or the strengthening of epidemiology units in the ministries of health and the organization of epidemiological surveillance and control programs for other communicable diseases. At global level the experience acquired in the smallpox eradication program led to the creation of the current and most successful Expanded Program of Immunization.

References

1. World Health Organization. "The Global Eradication of Samllpox". Final Report of the Global Commision for the Certification of Smallpox Eradication. December, 1979. Geneva; 1980.

2. Pan American Sanitary Bureau. Weekly Epidemiological Report. Vol. XLIII, No. 20; 19 May 1971; Washington; 1971

Source: Division of Health and Human Development, Health Situation Analysis Program, SHA, PAHO.