Map of life expectancy at birth from Global Education Project.

Monday, July 28, 2014

I suppose I should say something about the Ebola outbreak

There's been considerable alarm in the blogosphere about the outbreak of Ebola virus in west Africa. Naturally, the occasion for people in the U.S. to take notice is that two U.S. citizens have become infected. It was no big deal that about 660 Africans have died from the disease. Yes, that's a bummer and horrific for the people affected. However . . .

We need to get a grip. The chances that this will become a global pandemic, or even a major cause of death in Africa, are infinitesimal. Why do I say that? Although I have heard the elocutionists on National Pubic Radio call Ebola "highly contagious," actually it isn't. Transmission requires direct contact with bodily fluids.

Yes, that's true of HIV which is a global pandemic but there's a big difference. You can't walk around with Ebola virus appearing to be healthy and unwittingly infecting people through unprotected sex or sharing needles. There is a brief period during which people are potentially infectious but not visibly ill, but during that time you won't catch Ebola by sitting next to the person on an airplane. You'd need to join the Mile High Club.

If someone were to come down with Ebola in a developed country, they would be taken to the hospital in an ambulance by EMTs who already use what are called "universal precautions" to prevent contact with bodily fluids. They would be placed in isolation and cared for by people who are rigorously protected. Any recent contacts they had would be isolated until it was clear whether they were infected, and if they survived (which many will with supportive care) they would remain in isolation until they were not longer infectious.

The outbreak is sustained in Africa because many cases are in remote locations, or if they are in the city people don't get immediate attention from adequately equipped, trained and resourced services. In the remote areas, funerary practices in which relatives wash and otherwise touch the body also result in transmission. With adequate public education and infusion of resources, the outbreak in west Africa can be contained, and I expect it will be. If it continues, it will continue to infect and kill people at a rate of maybe tens per week. That's a drag but it's close to being the least of Africa's infectious disease problems. Really. Hundreds of thousands of Africans die from Malaria, TB and diarrheal diseases every year. We should care about that more than we do, but this is actually much less.

And no, it can't happen here. At least not on any large scale. Now, if the virus should mutate and become transmissible by causal contact, we'd have a problem. But there is no sign of that. So I hope folks will keep this in perspective.


mojrim said...

Once again, virulence cancels out vectoring. This is why herpes is possibly the most successful virus in history.

Cervantes said...

Yes, particularly the varieties that are not pathogenic at all in immunocompetent people, e.g. human cytomegalovirus. 90% of people are infected by the time they reach old age, and don't know it. Another example is Polyomavirus JC.