Going viral: Will the summer bring more Zika, West Nile outbreaks?

Adam’s Journal

This question comes from my friend Matt Langford and his wife, Ashley. They were wondering if we can expect to see more outbreaks of viruses like Zika and West Nile this summer?

Dr. Prescott Prescribes

The short answer is yes. Public health authorities anticipate a continued surge in mosquito-borne viruses such as West Nile, Zika, yellow fever and dengue. The primary reason for this change, most experts agree, is climate change.

In the past century, according NASA, the average temperature on the planet has risen by a bit over one degree, with a noticeable uptick in the past few decades. While that may not seem like much, when it comes to mosquitoes and disease transmission, small changes can throw a fragile equilibrium out of balance.

Since 1980, conditions have grown warmer and more humid in large parts of this country. As a result, mosquito season has also grown anywhere from five days to more than a month longer. In particular, it’s happened in the South (Florida, New Orleans, south Texas), where mosquitoes are now active for more than half of the year.

These changes have increased mosquito populations and the frequency with which people get bitten. They’ve also allowed mosquitoes to move north and thrive in greater numbers. In addition, scientists believe that warmer days may shorten the amount of time from when a mosquito bites an infected person to when it is then able to spread a mosquito-borne disease to another person.

Increasingly, diseases like Zika, yellow fever and dengue are being spread by a breed of mosquito, Aedes aegypti, that is particularly difficult to combat by traditional means.

These mosquitoes are present in more than half the states and regularly survive through the winter in sheltered spots as far north as the nation’s capital. They don’t need a pond or even an empty swimming pool to breed; they can reproduce in tiny pools of water. All they need is an empty soda can or even a discarded bottle cap turned toward the sky.

Unlike other breeds, which are happy to munch on all sorts of birds and animals, Aedes aegypti’s preferred meal is humans. So they fly into houses and conceal themselves in nooks and crannies, just awaiting the chance to feast on us.

At the same time that warming temperatures have increased the population of these mosquitoes, humans have become increasingly mobile. That, too, has contributed to the spread of conditions like Zika.

More and more, we travel to regions where many of these viruses had traditionally remained isolated. But we don’t stay. We get bitten, then hit the road.

When we return home, now infectious, we get bitten again — by the increasingly prevalent Aedes aegypti mosquito. After a week or so, that mosquito becomes capable of transmitting the virus. Its next human victim then contracts the virus.

To protect ourselves, traditional methods of mosquito control like spraying and ridding property of standing water are a good start. But because Aedes aegypti are quite resilient and wily, that is not enough. When outside, insect repellant is the best defense.

We can’t say for sure if this summer will bring a jump in cases of West Nile, Zika or other once-obscure viruses. But given the recent surge in mosquito-borne illnesses, take all necessary precautions to ensure that you and your family don’t get bitten.

Because this large coconut crab can snap its left claw as hard as a lion can bite, says the magazine’s Susan Milius. According to Okinawan researcher Shin-ichiro Oka, the shy crab doesn’t attack people unprovoked, but when he was getting one to grip a measurement probe, his hand was pinched twice, thankfully without breaking any bones. But, said Oka, “Although it was just a few minutes, it felt like eternal hell.” The strongest claw grip measured a force of about 1,765 newtons, “worse than crushing a toe under the force of the full weight of a fridge.” By way of comparison, a lion’s canine teeth bite with about 1,315 newtons, with some of its molars topping 2,000 newtons.

Coconut crabs begin their lives in seawater in the western Pacific and Indian Oceans. Eventually they move to dry land where they live for 50 years, maybe even double that number, yet they’d drown if forced back into water for too long. Adult males and females use their powerful left claw “for dismembering whatever the omnivorous scavengers find — road kill and other dead stuff, innards of palm trees and nuts” — and also coconuts.