Zika is sweeping the United States. The Centers for Disease Control and Prevention have thus far logged more than 3,100 cases in all 50 states — including 43 that have been acquired within the country’s borders.
Deadly outbreaks like Zika emerge from a complex web of environmental factors, including forest density, local water temperatures, and the health of nearby animal populations. So simply focusing on individual cases will forever be insufficient.
Public health officials frequently ignore this wider context. The medical community needs to broaden its focus. That’s the best way to prevent further infections — and stop outbreaks from occurring in the first place.
The efforts to rein in Zika illustrate the limits of direct treatment. In mid-September,, officials in Florida tripled the size of the zone in Miami Beach where they believe Zika is spreading. Some of the mosquitoes that transmit the virus have developed resistance to conventional insecticides. They can also breed in small pools and puddles, which are numerous in urban environments and difficult for sprayers to reach.
Zika is just one of the many vector-borne viruses ravaging communities across the globe. The same species of mosquito can also transmit yellow fever, Chikungunya, and dengue fever. The dengue virus infects nearly 400 million people every year. The 2014 Ebola outbreak that claimed over 11,000 lives in West Africa has been linked to a single infected fruit bat.
Worldwide, animal-borne diseases kill 2 million people every year.
Broader environmental changes affect the health of humans and animals. Increasing global and local travel — by people, animals, and insects — in combination with global warming has raised the temperature of many environments. That’s increase the number of mosquito breeding sites and expanded their disease transmission range.
Or look at deforestation. In parts of Africa and South America, forest clearing has pushed infected animals into human communities. Expanding human populations have also moved into previously virgin forest areas. That’s facilitated closer interaction between sylvatic viruses and people.
The public health field must expand its scope to recognize and address such realities.
That evolution starts with training. Public health programs should not operate within academic silos. They need to take a multi-disciplinary approach that draws on the expertise of a wide range of departments.
Take Zika. Understanding its protein structure is certainly important for researchers and clinicians. But so is comprehending the environments that breed carrier mosquitos.
Some institutions have already take steps in this direction. The University of Florida’s public health master’s program offers a “One Health” concentration that combines veterinary sciences with environmental health studies. The University of California at Davis runs a month-long, public health field course in which participants directly study the environmental causes of disease.
At my institution, St. George’s University, we offer a course in holistic public health and run complementary, practical training programs in partnership with our neighbors in Grenada. Medical, veterinary and public health students work alongside certified professionals to provide check-ups for humans and animals alike –whilst also paying attention to the environment in which they are working.
Zika has come to American soil. Combating this virus and others like it requires an expansive broad-based approach to medicine that goes beyond individual infections — to address the root causes of disease, and its prevention Physicians, veterinarians and public health professionals need to be trained in — and knowledgeable about — the intimate links between humans, animals, and nature.
Dr. Calum Macpherson is the Dean of the School of Graduate Studies and Director of Research at St. George’s University in Grenada.