Let’s talk about Ebola!
The Ebola virus, which was first isolated during a 1976 epidemic in Zaire and Sudan, is an irregularly-shaped, threadlike virus with its genetic information in the form of RNA. It’s thought that its natural reservoir is fruit bats, who can carry Ebola without getting any symptoms, and we know that monkeys can also get infected with Ebola and pass it on to humans. How the monkeys get it isn’t known—they might munch on fruit that’s been partially eaten by the bats—and aside from a few cases where people have butchered monkeys for food, the origin of most Ebola outbreaks tends to be murky.
After a 2 to 21 day incubation period in the body, the symptoms of an Ebola infection tend to come on suddenly, starting with a fever and headache and leading to vomiting, diarrhea, and a nasty rash. In advanced cases, bleeding from multiple orifices occurs, followed by multi-organ dysfunction and death. The fatality rate can be from around 50-90%, with the Zaire strain being the most fatal. The strain currently going around is 97% identical to the Zaire strain.
There’s no specific treatment for Ebola and no vaccine for it exists. Patients are only contagious after the symptoms start and then begin shedding the virus in some of their bodily fluids, so preventative measures—like those full-body suits health care workers wear—aim to keep people out of contact with those fluids and stuff they might’ve gotten on. The virus doesn’t seem to survive in saliva very well and doesn’t show up in urine, which is good news for anyone worried about foodborne or waterborne transmission. Most exposures are probably through blood, and the virus might also appear in semen and breastmilk.
If you care about public health, you’ve got to care about mental health. As a group, psychiatric disorders cause more social and financial cost worldwide than any other group of disorders—and they’re closely related to such major causes of disability and death as heart attacks, strokes, diabetes, and Alzheimer’s disease.
Check out this educational drama throwback, created by the International Health Board in 1920 on hookworm, and which one reviewer called “the best and only film of its kind on hookworm disease.”
Oh my gosh, this is so cool! The life cycle of the parasite is shown correctly (hookworm does indeed penetrate the skin, go from the heart to the lungs, then get swallowed to end up in the small intestine) and the disease is still diagnosed through examination of a stool sample. Though no longer a problem in the US due to advances in sanitation, it’s still an issue in poorer parts of the world, such as sub-Saharan Africa and southeast Asia.
An interesting note about hookworms: they and some related worms are currently being studied as a treatment for conditions like allergies and Crohn’s disease. The idea behind this is that humans coexisted with parasites for so much of history that without them, the immune system tends to malfunction. Clinical trials have been going for a decade or so, with some promising results.
Yesterday I got back from a trip to Yellowstone where I had the opportunity to take photos of some really interesting microorganisms! The beautiful coloration of the Morning Glory pool here is due to billions of thermophilic (heat-loving) organisms. The first of these were discovered in 1965, living happily in the park at temperatures around 82 to 88 degrees C, and about a year afterwards a particularly important one was isolated—Thermus aquaticus. Two decades later, T. aquaticus would serve as the source of Taq polymerase, the heat-resistant enzyme that made it possible to rapidly copy DNA through PCR, revolutionizing molecular biology.
How do microorganisms survive at temperatures like that? Their main challenge is keeping their structures from coming apart, so many have cell membranes and proteins with higher levels of molecular bonding than usual. Their DNA often has more guanine and cytosine than adenine and thymine—this is because G and C stick together with three hydrogen bonds, while A and T only use two.
These organisms also may account for the possibility of damage by having multiple chromosome copies on hand and cleaning up mRNA (which is ‘read’ by cellular machinery to make proteins) quickly, before it has the chance to start getting messed up. If temperatures get really bad—above what an organism likes—many produce heat shock proteins. These work as molecular chaperones, making sure that other proteins fold correctly and don’t assume forms that aren’t functional.
It’s worth noting that these organisms are thought to be similar to early forms of life, especially because many deal with additional challenges that were found in ancient environments, such as high pressures, high salt content and lack of oxygen. In this way, they can serve as a neat window to the past.
Photo is mine, information is from here.
Oral manifestations of childhood illnesses
1. Oral thrush - Caused by the Candida fungus overgrowing on the mucous membranes of the mouth. Also known as candidiasis when it occurs elsewhere on the body (such as vaginal candidiasis).
2. Varicella - Chicken pox. Have you ever had chicken pox in your mouth? It’s awful.
3. Stomatitis herpetica or Aphthosa [Herpetic stomatitis] - Caused by the same herpes infection of the mouth that causes cold sores, but blisters and mild ulceration can occur. This condition usually occurs when the child first contracts Herpes simplex I.
4. Stomatitis ulcerosa or Scorbutus - The oral manifestation of scurvy in children. The bone weakness, dry mouth, and immune dysfunction in scurvy often causes tooth weakening, loosening, and extreme gingivitis.
5. Follicular tonsillitis - The “standard” childhood tonsillitis, with infection of the palatine tonsils. If the infection doesn’t subside, removal of the tonsils is still the most common treatment.
6. Diphtheria - There are many oral manifestations of diphtheria, including “pseudo-membranes” covering the trachea, severely impairing breathing. The exotoxins exuded by Corynebacterium diphtherium can also cause thick, thrush-like patches in the pharyngotrachea.
Pediatrics: The Hygienic and and Medical Treatment of Children. Thomas Morgan Rotch, 1901.
Cool! An 1897 version of this book is freely available online.
Many ideas have left the world of science and made their way into everyday language — and unfortunately, they are almost always used incorrectly. We asked a group of scientists to tell us which scientific terms they believe are the most widely misunderstood. Here are ten of them.
Man, there are a lot of my pet peeves in here!
Nice infographic from the CDC! #4 is particularly good advice this time of year.
(And yes, you can in fact find those inspection records in many US states if you’re curious. They’re a bit haphazard and it looks as though restaurants are handled at the county level, but I was able to look up the grocery stores in my area through my state’s database.)