Disease Detective Henderson
By Mollika Wahab
In 1975, two-year-old Rahima Banu of Kuralia village in Bhola contracted the last known case of naturally occurring Variola major smallpox, the more deadly strain of the disease. Her case was reported on October 16 of that year.
Elsewhere, the last natural case of Variola minor smallpox, a less fatal form of the virus, was in Somalia in October 1977. Ali Maow Maalin, a 23-year-old hospital cook in Merca, caught the infection while escorting some patients to a clinic.
They were lucky to survive the horrendous disease, which killed an estimated 300 million in the 20th Century until a World Health Organisation (WHO) vaccination campaign successfully eradicated it by 1979.
The person who spearheaded the international effort to successfully wipe out a human disease for the first time in history was Donald Ainslie Henderson. The American epidemiologist served as the director of WHOs Global Smallpox Eradication Campaign from 1966 to 1977. Known popularly as DA, Henderson died in Maryland, USA, on August 19. He was 87. His lifes work helped save tens of millions of lives.
A self-described disease detective, Henderson spent the defining years of his career as an official of the US Centers for Disease Control and Prevention, then called the Communicable Disease Center (CDC). Loaned to the WHO in Geneva, for a decade he commanded a small cadre of public health officials and an army of field workers in an endeavour that amounted to a medical miracle. Later, he served as dean of Johns Hopkins Universitys school of public health, and as a science and bioterrorism adviser to three US presidents. He authored Smallpox: The Death of a Disease in 2009.
I think it can be fairly said that the smallpox eradication was the single greatest achievement in the history of medicine, said Richard Preston, the bestselling author of The Demon in the Freezer about smallpox. He described Henderson as a Sherman tank of a human being he simply rolled over bureaucrats who got in his way.
Seven years after it was proposed at the World Health Assembly, the eradication campaign began in earnest in 1966 with the appointment of DA Henderson. Although mass vaccinations calmed fears, it was not always the most medically efficient way to combat the disease. Henderson and his team developed a strategy of containment and surveillance.
Every time there was an outbreak, a WHO team would arrive, vaccinate and isolate those who were ill and trace and vaccinate all their contacts. Effectively they ring-fenced the disease until it had no way of moving on to its next victim. The eradication teams also actively hunted down the disease, travelling with a recognition card showing a baby with smallpox, to explain to people what the illness looked like. Rewards were offered to encourage reporting of cases.
Rahima Banus case was reported by an eight-year-old girl, Bilkisunnessa, who was reportedly paid Tk 250. Information on the case was forwarded via telegram to Henderson. A WHO team arrived and cared for the child, who recovered fully.
The smallpox campaign, which cost an estimated US$300 million, benefited from an effective vaccine, ingeniously reconstituted in a freeze-dried form that could withstand the high temperature of tropical environments. It was administered by a sharp, two-pronged rod that was easy for non-professionals to use. The nature of smallpox also offered advantages _ with its tell-tale sores, it was easy to identify in patients, and it had no animal vector, or means of transmission.
In an interview with the Global Health Chronicles in 2009, Henderson said: In the summer of 1973, we were down to just five countries that had smallpox, just five. It was India, Pakistan, Nepal, Bangladesh in Asia and Ethiopia in Africa.
The combined population of those countries was around 700 million. In India, about 120,000 health workers were mobilised to undertake a village by village search throughout the whole country over 10-day periods in 1974. The last cases there were reported in May of 1975.
Henderson continued: Meanwhile, Bangladesh was going through tragedy after tragedy of flood and famine and we had an exhausted group really fighting to get rid of it in Bangladesh, which is a story unto itself. So, on August 15, the director general and I headed for Bangladesh. They only had I dont know, something like maybe 80 villages infected at that point. It was just really coming way down and we felt, my gosh! I think we are going to be rid of this bad disease for all the world. It was a very severe time for smallpox. That would have been it.
So we are on our way to the airport and got the word, all flights are cancelled. The president of the country, really the founding father of the country, Mujibur Rahman, had been assassinated along with his entire family. Martial law had been declared. Troops were moving to the border.. But for some reason,
the international group was laid low. They worked locally, they kept out of the way. They went back to work and finally, in October of 75 it was all done in Asia.
On October 26, 1977, when Ali Maow Maalin was diagnosed, an intensive tracing and vaccination campaign led to 54,777 people getting vaccinated in the next two weeks in Somalia. The disease was cornered.
That was the end of the smallpox. We had to spend two more years working in the countries to make sure it was really the last one, Henderson said. We were dealing with 10 to 15 million cases of smallpox a year, 2 million deaths a year and 10 years later, we have zero cases, and zero deaths. Thats pretty dramatic.
When Henderson left the WHO in 1977, he quipped that as the chief expert on a disease that had been wiped out, he was left there high and dry with no marketable skills.
For millennia, smallpox had ravaged its way around the world. Caused by the Variola virus, it was an exceptionally painful and gruesome disease. Victims suffered from fever before developing a rash of the pustules that gave the disease its nickname: the speckled monster. It killed a third of its victims and left survivors disfigured, sometimes blind.
Henderson was born on September 7, 1928 in Lakewood, Ohio. His father was an engineer and his mother a nurse. He graduated from Oberlin College, University of Rochester School of Medicine and Johns Hopkins School of Hygiene and Public.
He is survived by his wife Nana, daughter, Leigh, and sons Douglas and David.
Reference: CDC, WHO, GHC
