Oct 262017

WHO (World Health Organization) chose this date, approximately 2 years after the last known case of naturally occurring smallpox, to announce that the disease has been completely eradicated from the world – a rare and stunning event. Smallpox is a special human disease in that it is one of the few that cannot migrate to other species. It can infect humans only, so the WHO set the goal of eliminating smallpox from human hosts because once there were no infected humans, the disease would be effectively extinct. There’s the extinction of one endangered species that no one laments. Smallpox exists now only in carefully guarded lab specimens (available for ongoing testing), which once in a while are mishandled and cause someone to be infected. But for all intents and purposes smallpox has been wiped out.

Not so very long ago, smallpox was a worldwide scourge with infants (and adults) dying regularly on all continents. Then Edward Jenner came along and vaccination was born. https://www.bookofdaystales.com/edward-jenner-and-smallpox/ Vaccination was very effective in Europe, but the rest of the world lagged behind – especially Africa. A concerted effort by the WHO got the job done, though, in the end. Into my teens (1960s) I was required to prove I was vaccinated against smallpox when traveling abroad, but by my twenties it all came to an end. Hooray.

Smallpox is caused by two strains of virus, Variola major and V. minor. V. minor is the rarer of the two strains, and causes a much less severe disease (sometimes called alastrim), with a fatality rate of around 1%. No treatment is available, and the only protection is vaccination. The virus is usually transmitted by prolonged face-to-face contact with a person showing symptoms. The incubation period averages 12–14 days. Smallpox was still causing an estimated 2 million deaths every year as late as 1967.

The global effort to eradicate smallpox from endemic areas, particularly in Africa, began in 1959 with a mass vaccination campaign. This approach met with little success, and a more-effective targeted approach was developed in the late 1960s. This involved active surveillance by case hunting, combined with rapid containment, by intensive vaccination, of infection in areas reporting outbreaks. The majority of African countries were free from smallpox by 1972. By the end of 1975, the virus had been eradicated worldwide except in Ethiopia, Somalia, and Kenya. The nomadic people of the Ogaden Desert retained endemic smallpox with an unusually mild form of the disease, which facilitated persistence in the population. From 1975, WHO efforts were concentrated on this region. Ethiopia saw its last case in August 1976 and Kenya in February 1977.

Somalia proved particularly challenging because much of its population of 3.5 million was nomadic. A mass vaccination campaign in the country in 1969 had failed because many nomadic people in the region had cultural objections to vaccination, and either refused or avoided it. Elimination efforts relied on an intensive reporting system. A severe drought in 1975 exacerbated the difficulties by increasing movement across the border with Ethiopia, and frequent outbreaks continued. In March 1977, surveillance efforts found over 3000 cases in the south of the country.The Somali government declared a state of emergency and successfully appealed to the United Nations for assistance. By June of that year, when the outbreak peaked, 3000 Somali health workers supervised by 23