By: Alanna Shaikh

Mexico, Colombia, and Guatemala are making huge progress against river blindness, aka onchocerciasis. Colombia has eliminated river blindness from within its borders, the first country in Latin America to do so. Mexico and Guatemala have broken the cycle of transmission, and they’re ready to stop mass drug administration next year.

Elimination is a pretty clear term. It means that the disease, while still present on our planet, is down to zero in one particular region; in this case, Colombia. But what does it mean to break the cycle of transmission? Well, onchocerciasis is a tiny parasitic worm[1] that has a pretty complicated life cycle, and one particular kind of fly is essential to the survival of the disease. Without those flies, the disease is not transmitted and dies out.

To break the cycle of transmission, you spray insecticide in the areas of fast moving rivers where the flies breed. No more flies, no more onchocerciasis. According to the World Health Organization (WHO), it takes fourteen years of spraying to totally eliminate the reservoir of adult onchocerciasis worms and therefore make sure that the disease is gone. Once you’ve reached that point, it takes three more years of close monitoring to ensure that the disease really is gone. If there really are no cases in those three years, then, like Colombia, your country can be certified as having eliminated the disease.

Mexico and Guatemala aren’t quite there yet. They have completed their spraying period, and have entered the monitoring period. By the end of 2014 we’ll know for sure that onchocerciasis has truly been eliminated, and they’ll get their WHO certification. They really ought to get a trophy or something for that – maybe a giant golden statue of the onchocerciasis worm? Instead, though, it’s just a regular old certificate and some good press attention.[2][3]

Aside from the vocabulary of elimination and interruption, why do we care about onchocerciasis? It’s the second largest cause of infectious blindness, for one thing. In addition to the blindness, onchocerciasis causes rashes, lesions, intense itching and depigmentation of the skin; lymphadenitis, which results in hanging groins and elephantiasis of the genitals; and general debilitation. Not exactly the kind of thing that’s good for the population, the health system, or the economy of a nation. Also, like most NTDs, it hits children the hardest.

In this economy of declining funds for global health, successes like these are a reminder of just how efficient well-chosen health interventions can be. Eliminating river blindness will save money – and human suffering – from here on into infinity. The cost of disease surveillance is far less than the cost of actively fighting a disease. Mexico, Guatemala, and Colombia didn’t give up, even when resources were tight, and their populations are the healthier for it.

 

 

Alanna Shaikh is an expert in health consulting, writing about global health for UN Dispatch and about international relief and development at Blood & Milk. She also serves as a frequently contributing blogger to ‘End the Neglect.’ The views and opinions expressed by guest bloggers are not necessarily the views and opinions of the Global Network. All opinions expressed here are Alanna’s own and not those of any employer or the US government.