West Nile, Ebola, and Cholera: Lessons from Three Epidemics

In the past month, we’ve seen the United States’ worst outbreak of West Nile Virus, Ebola in Uganda and the Democratic Republic of the Congo (DRC), and cholera in Sierra Leone that’s spread to its West African neighbors. What lessons can be learned from these three epidemics?

West Nile, which has only been endemic to the U.S. for the last 13 years, has infected more than 1,000 people this summer, of whom more than 40 have died. This has led to outdoor pesticide spraying in Dallas–for the first time since 1966–to control the mosquitoes that carry the disease. About one in 150 infected people must be hospitalized, and 10 percent of those patients die.

Ebola, an often fatal hemorrhagic fever, killed 19 in Uganda in July and has now been confirmed in the DRC, where it has killed 10 people. Like West Nile Virus, there is no vaccine and no treatment for  Ebola, beyond symptom management, and the mortality rate can climb to 70 percent or higher.

Finally, a major epidemic of cholera has killed 220 people and infected more than 12,000 in 10 of the 12 districts in the country. Cholera is spread through contaminated water and food. The vast majority of the Sierra Leonean population lives without adequate sanitation or access to clean drinking water, and Sierra Leone ranks 180 out of 187 countries on the Human Development Index. Overcrowded slum conditions have exacerbated the spread of the disease, and flooding from the rainy season (which peaks in September) will not help. Like Ebola, cholera is extremely virulent. According to the WHO, 80 percent of cholera cases can be treated with oral re-hydration salts, and proper care and treatment can drop the mortality rate to below one percent.

I am certainly no epidemiologist, but there are wider global health, development, and sustainability lessons for all three cases.

In hotter weather, mosquito populations grow and the viral load in their salivary glands increases, which most likely exacerbated the spread of West Nile this year, as it did in 1999 and 2003. West Nile and other mosquito-borne diseases will start to increase in places where we’ve not seen them before as global temperatures continue to rise. Although widespread efforts to curb global warming by business, governments, and society must continue, it is possible that these kinds of outbreaks might be our new reality. Discussions about how to control mosquito populations–perhaps including the much-resisted reintroduction of DDT spraying–will start happening in earnest.

Ebola is a trickier situation. It tends to blow up and then burn out quickly, which is the only silver lining of the virus. Better health education and outreach in ebola-prone areas could help prevent future outbreaks of the disease. IRIN has reported that the consumption of infected wild animals may be to blame for the DRC outbreak, which may be unrelated to the Ugandan cases. Since “bush meat” is a major source of protein for many people in the DRC and other disadvantaged countries, greater efforts to develop infrastructure and economies are also required.

Similarly, cholera is a disease of poverty. This is not an infection that one sees in Europe or the United States anymore but rather in developing nations, especially in refugee camps and slums. Treatment is easy and cheap–but prevention requires access to clean drinking water and better living conditions.

As I’ve written many times in the past, no single health issue can exist in a vacuum–it is interconnected with development, sustainability, economics, and so on. These diseases require more than a vaccine, treatment, or epidemic control. Education overall as well as health education and awareness, reduction of our carbon emissions, and a renewed focus on infrastructural and economic development are all required. We must take more holistic approaches to global health–otherwise, we’re merely treating the symptoms of the problem.

Header photo: the California National Guard, via Flickr, CC BY 2.0.