Posts Tagged ebola disease
Here’s few ideas that popped into my head over the past few days about the presence of ebola disease in the United States. Keep in mind, a lot of the talk about ebola lately is political. It’s also epidemiological. I’m not a politician, nor am I a political pundit, nor an epidemiologist. As a PhD virologist, I studied viruses in the laboratory, so that’s the basic foundation from where my comments come. Here’s what I think.
First, the Centers for Disease Control in Atlanta has been criticized for its lax guidelines on what kind of protective clothing persons who are caring for an ebola-infected patient should wear. But from the point of view of a virologist in the hospital, the hospital should have known better. After all, we’ve been seeing pictures from West Africa for months of people treating ebola victims there, and they’re dressed in total-body containment suits. The hospital should have known. That’s what infection control is for. I understand the two nurses who contracted ebola while caring for the index patient were not wearing total body protection. I find it difficult to believe that knowing all we know about ebola, the hospital didn’t insist on total body protection from the very first.
Second, the fact that those two nurses got infected while allowing small areas of skin to go unprotected suggests that somehow the virus penetrated their skin. Right now, it’s unknown how they got infected. Perhaps they had small open wounds or sores on the unprotected area of skin, and the virus splashed on that and got through the skin. But we have to keep in mind that they were only two nurses out of a larger number of people who were caring for the patient. If the others were wearing the same type of protective equipment, and didn’t get infected, then there’s a question of why only those two were infected. Or is it possible that ebola virus can penetrate intact skin? That’s scary.
I got my baptism under fire back in the 1980’s and 90’s with the AIDS virus. Back then, when we worked with HIV, we assumed that the virus wouldn’t penetrate intact skin. That turned out to be true. Now we’re making the same assumption about ebola and perhaps it isn’t true. This will take some study.
Third, I’ve seen warnings from health officials on TV and on the internet that ebola can be caught only by direct contact with a patient or with a patient’s bodily fluids. They say that it can’t be caught through food, water, air, etc. As someone who has done studies with inactivation of viruses in water and buffers, I’m a little suspicious about the blanket statement that ebola can’t be transmitted by water. I assume, like everyone else, that the ebola virus is inactivated by the chlorine in drinking water. But a lot of the drinking water in Africa isn’t treated with chlorine, and I think it’s a mistake to assume that the virus can’t be transmitted by water, or even food. Has anyone done any studies to find out?
Fourth, the fact that we have to use such heavy protective gear while working with ebola-infected patients is a recognition that the ebola virus is one of the most infectious agents we’ve ever seen. The only virus I can think of that even comes close to the infectivity of ebola is smallpox, and that has been eradicated from the earth. Marburg fever virus is also very infectious, but it has been kept under control. I don’t know what the ratio of virus particles to infectious units is for ebola, but it may be very low, possibly in the range of one or two. That’s also scary. That means that if ebola virus does somehow survive in water, only a small number of particles can cause an infection. The fact that two nurses got infected while wearing protective equipment also suggests the ratio is very small.