What might change in the frequency of zoonotic pathogen emergence and spread from intermediate or amplifier animal species. For some emerging zoonoses, the spread of infections in domestic animal species is the key factor.
For both Nipah and MERS the latter caused by a coronavirus , the spread from bats to intermediate domestic animal hosts was important in the subsequent emergence of the disease in humans. Influenza viruses have been responsible for many epidemics over the past centuries, including the flu pandemic of — that killed more people than any other documented pandemic—one-third of the world was infected and around 50 million people died.
Interestingly, in the H5N1 avian flu epidemic of — that caused global animal and human health concerns, H5N1 infections became endemic in Indonesia but were relatively quickly eliminated following their introduction in West Africa, perhaps because Indonesia at that time had much greater poultry densities than West Africa. But West African poultry density is now catching up to Asia.
What is changing in human societies that facilitates the spread of emerging zoonotic pathogens. Increasing human populations, urbanization, and rising incomes are changing Africa in fundamental ways. One major change is a dramatic increase in air travel between Africa and the rest of the world. While traditionally most African travel connections have been through Europe or the Middle East, in the past decade the number of African connections to Asia has been rising.
Relative to COVID, Marius Gilbert and colleagues combined data on Chinese air travel connections with available indices on health preparedness and infectious disease vulnerability indices to rank country risk. As noted above, Ebola outbreaks in Africa have usually been contained locally; the West Africa Ebola epidemic spread through countries with very weak health systems.
In , an Ebola outbreak in the Democratic Republic of Congo persisted as it occurred in a conflict zone. Implications and opportunities for controlling emerging infectious diseases in Africa. The rising risk of emergence and spread of zoonoses in Africa has significant consequences for the continent and the rest of the world.
Epidemics in recent decades have varied in both their causes and effects and there are no common guidelines for the prevention or early control of zoonotic diseases. Governments and organizations should also adopt a coordinated One Health response across human, animal and environmental health.
Bringing these three disciplines together is essential to respond to the increasing threat of emerging zoonoses in Africa. The record thus far on COVID and on past disease outbreaks shows that early, effective, and sustained response is essential to winning the battle over these diseases. Innovative use of information and communication tools and platforms and engagement of local communities are crucial to improved disease surveillance and effective response. Building these systems requires demand from the public commitment from policymakers and investors.
COVID is a game-changer. It has shocked the world and continues to disrupt the daily lives of billions of people. Nature speaks to him about his work and views on ensuring that Africa prepares for the next pandemic. This means I do not need to travel frequently back to Washington. Under the terms of my contract with the WSU, I supervise PhD students at the University of Nairobi, collaborate with other faculties there, and write grant applications to bring funding to the institution.
This will be achieved through training and mentorship, so that long after this generation of researchers is gone, there will be others to take over. This is an especially important task here: East and Central Africa is where many of these infectious diseases originate.
Ten centres were established around the world. I recruited a team of scientists in East and Central Africa, with myself as the principal investigator, and we applied to set up and run the centre in charge of this region. Career resources for African scientists. Our job is to ask the right research questions to prevent disease outbreaks in East and Central Africa, and we currently have field studies going on in Kenya, Uganda, Tanzania and the Democratic Republic of the Congo DRC.
I lived in the United States full-time from , but came back to Kenya in to study emerging zoonotic diseases — which include Rift Valley fever, swine flu and Ebola — and to apply for grants from international organizations. From to , I was working with the US Centers for Disease Control and Prevention as the head of labs, and in other roles touching on its One Health programme in Kenya, and would travel between the two countries when needed. Rare pathogens in those animals could jump between wildlife into humans, often through a livestock intermediary, and cause deadly disease outbreaks.
Although the COVID pandemic did not originate in Africa, our region is a hotspot for emerging infectious diseases because of the range of wildlife and the number of human—wildlife interactions. First reported in humans in , MERS-CoV was initially transmitted to humans through dromedary camels Camelus dromedarius and continues to cause human infections and deaths. A researcher tests a camel in Marsabit, Kenya, for the coronavirus behind Middle East respiratory syndrome.
We already have research facilities in some high-risk areas, including in Goma, the capital of North Kivu province in the eastern part of the DRC, close to the Congo Basin. Tropical regions, rich in host biodiversity , already hold a large pool of pathogens, greatly increasing the chance that a novel pathogen will emerge. On both continents, many families depend on subsistence farming and a minuscule supply of livestock. Disease control, feed supplementation and housing for those animals is extremely limited.
Cattle, chickens and pigs, which can carry endemic disease , are often in close contact with each other, a variety of nondomestic animals and humans. And not just on the farms: Live animal markets , commonplace throughout Asia and Africa, feature crowded conditions and the intimate mixing of multiple species, including humans. This too plays a key role in how a killer pathogen could emerge and spread between species.
Another risk: bushmeat hunting and butchering, which is particularly widespread in sub-Saharan Africa. These activities, as they threaten animal species and irrevocably change ecosystems , also bring people and wild animals together. Bushmeat hunting is a clear and primary path for zoonotic disease transmission. So is traditional Chinese medicine , which purports to provide remedies for a host of conditions like arthritis, epilepsy and erectile dysfunction.
Although no scientific evidence exists to support most of the claims, Asia is an enormous consumer of traditional Chinese medicine products. Tigers, bears, rhinos, pangolins and other animal species are poached so their body parts can be mixed into these questionable medications.
This, too, is a major contributor to increasing animal-human interactions. The viruses, thousands of them, continue to evolve.
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