If the past few years have taught us anything, it’s that our well-being is intimately linked to the health of animals.

The current Ebola epidemic probably got its start when someone came into contact with an infected animal, perhaps a monkey or a fruit bat. The virus causing Middle East respiratory syndrome appears to spread from camels to humans.

Yet animal pathogens remain a scientific terra incognita. Researchers have begun cornering animals in far-flung parts of the world to learn more about what infects them.

Continue reading “Rats and Their Alarming Bugs” →

News that a nurse in full protective gear had become infected with the Ebola virus raised some disturbing questions on Monday. Has the virus evolved into some kind of super-pathogen? Might it mutate into something even more terrifying in the months to come?

Evolutionary biologists who study viruses generally agree on the answers to those two questions: no, and probably not.

The Ebola viruses buffeting West Africa today are not fundamentally different from those in previous outbreaks, they say. And it is highly unlikely that natural selection will give the viruses the ability to spread more easily, particularly by becoming airborne.

Continue reading “Scientists Rein In Fears of Ebola, a Virus Whose Mysteries Tend to Invite Speculation” →

Invasive species are both a fact of life and a scientific puzzle. Humans transport animals and plants thousands of miles from where they first evolved — sometimes accidentally, sometimes intentionally. Many of those species die off in their new homes. Some barely eke out an existence.

But some become ecological nightmares. In the Northeast, emerald ash borers are destroying ash trees, while Japanese barberry is blanketing forest floors, outcompeting native plants. Scientists aren’t certain why species like these are proving superior so far from home.

Continue reading “Turning to Darwin to Solve the Mystery of Invasive Species” →

As much as we may try to deny it, Earth’s cycle of day and night rules our lives.

When the sun sets, the encroaching darkness sets off a chain of molecular events spreading from our eyes to our pineal gland, which oozes a hormone called melatonin into the brain. When the melatonin latches onto neurons, it alters their electrical rhythm, nudging the brain into the realm of sleep.

At dawn, sunlight snuffs out the melatonin, forcing the brain back to its wakeful pattern again.

Continue reading “The Evolution of Sleep: 700 Million Years of Melatonin” →

In the early 1920s, farmers in New Jersey noticed their potatoes were shriveling, their leaves becoming deformed. The plants were sick with an illness that came to be known as potato spindle tuber disease. But it took almost five decades for someone to find the cause.

In 1971, Theodor O. Diener, a plant pathologist at the Department of Agriculture, discovered that the culprit is an inconceivably tiny pathogen — one-80th the size of a virus. Dr. Diener called it a viroid.

Since Dr. Diener’s initial discovery, scientists have identified nearly three dozen species of viroids that attack crops from tomatoes to coconuts, as well as flowers such as dahlias and chrysanthemums.

Continue reading “A Tiny Emissary From the Ancient Past” →