YSPH researcher discusses past, present and future of deadly viral disease
Ebola is a terrible disease, but its public health toll pales in comparison to three other infectious diseases—HIV/AIDS, malaria and tuberculosis—each of which is entrenched and continues to ravage Africa.
Malaria alone kills nearly half a million people each year; AIDS is responsible for some two million deaths annually; and there are more than eight million new TB cases each year in Africa alone.
The number of Ebola infections from the current outbreak, meanwhile, is most likely approaching15, 000, when under-reporting is taken into account. While many of its victims will ultimately perish, it does not now appear that Ebola will become a killer on the same scale as others diseases devastating Sub-Saharan Africa, but its impact on specific countries will be catastrophic James “Jamie” Childs, Sc.D., a senior research scientist and lecturer in the Department of Epidemiology of Microbial Diseases at the Yale School of Public Health, said during a Global Health Seminar on Ebola at The Anlyan Center.
Childs’s perspective on Ebola comes with personal experience—he spent weeks on the ground in Zaire (now the Democratic Republic of the Congo) responding to an outbreak of the viral disease in 1995 that killed more than 300 people.
He recounted the grim experience for a large audience Monday evening and how health care workers suffered the brunt of that outbreak. This effectively eliminated the people who were needed the most to provide care and assistance to the public. Within a short time, hospitals were unable to effectively respond to successive waves of the disease.
Mass graves were dug, but the region’s traditional burial rituals only worsened the epidemic. Family members washed the bodies of the deceased in preparation for burial and unwittingly came into contact with the virus, which is spread through contact with bodily fluids.
Once transmitted, the disease’s course is relentless and oftentimes deadly, he said.
Symptoms include vomiting, diarrhea, nausea, sore throat, rashes and, in some cases, bleeding from membranes.
“People are incredibly weakened,” Childs said. Death occurs for many within six to 16 days after symptoms appear.
The first recorded case of Ebola, named after an eponymous river close to where the outbreak occurred, was in 1976. The single stranded negative-sense virus, wormlike in appearance under a microscope, is believed to reside in bats. Bats, in turn, transmit it either by infecting other mammals, such as apes and antelopes, which are eaten by many people as bush meat, or when bats are hunted and eaten directly by people.
To date, five species of the virus have been identified and some are more virulent than others. In a worst case scenario, up to 90 percent of those infected with Ebola can die. Childs said that as many as 70 percent of those infected in the current outbreak could perish.
Historically, West Africa, where the current outbreak is occurring, has been relatively untouched by Ebola. Liberia, Sierra Leone and Guinea are currently battling the disease and Mali recently confirmed that it also has an infection.
The current epidemic is spreading at a “fair clip” and Childs does not believe it is plateauing. Some estimate that more than 200,000 people in Liberia alone could contract the disease. Patient zero, the first person infected, can be traced back to a two-year-old girl in Guinea late last year who is believed to have eaten infected bat meat. From there, the zoonotic disease spread to her family, community members, health care workers and then across national and international borders.
Beyond its severe health consequences, Ebola also has the potential to devastate the region in less obvious ways. There will likely be severe economic turmoil (some estimate that the GDP in afflicted areas could contract by double digits), and social upheaval and famine are possible. As governments in these underserved countries struggle to respond to Ebola, there are also fewer resources to address other endemic maladies such as malaria, hookworm and diarrhea.
The current Ebola epidemic, by far the largest in the history of the disease, is being abetted by modern transportation, which allows people to travel from a country where infection is pronounced to virtually any place on the planet in less than a day. This “spider web of connectivity” recently introduced the disease to the United States where one person has died and a number of others are under quarantine. States have responded with a patchwork of policies as they struggle to protect public health against a disease that is not well known or understood.
Medical efforts, meanwhile, continue to find an immunotherapy response to the disease and experimental drugs to fight Ebola, such as ZMapp, are under development. Childs said but more data is needed to determine if the drug, while promising, is safe and effective against the disease.
Childs is a zoonotic disease specialist at the Yale School of Public Health and currently works on a range of zoonotic diseases, including hantaviruses, arenaviruses, rabies and vector-borne and environmentally transmitted bacteria, including rickettsia, borrelia and leptospira. Prior to joining Yale in 2004, he worked at the Centers for Disease Control and Prevention.
The Global Health Seminar is a year-long elective course for students in the health professions to develop an understanding of key aspects of global health research and practice. The Yale schools of public health, medicine, nursing and the Physician Associate Program at Yale contribute to the seminar.
“With speakers from Yale and from around the world, we are able to provide students with a foundation of key issues upon which they may base future research, service, and clinical pursuits in the field of global health,” said Michael Skonieczny, executive director of the Global Health Leadership Institute at Yale and YSPH faculty adviser for the seminar.
The next seminar on Nov. 3 features Gregg Gonsalves, a Ph.D. student at the School of Public Health. He will discuss global health and justice.