Public Health: Move over grizzlies: These bugs are dangerous predators | Health and Fitness

When I first decided to move to Montana, friends and family liked to tease me by telling me horror stories about the state’s most infamous predators.

Grizzlies will menace you from your own front porch, they said. Cougars will stalk you in the streets. I confess these tales made me a trifle nervous.

I know better now, of course. Yes, such terrible encounters do happen — rarely — in some parts of the state. But after 37 years here, I’ve never had one. I’ve learned that these animals want to avoid me as much as I want to avoid them.

But not every predator in Montana is as conspicuous as a grizzly or mountain lion. And not every predator tries to avoid human contact.

At least two creatures spend the warm months lurking nearby, scheming to attack us and drink our blood. They’re mosquitoes and ticks, and they’re disturbingly successful at making us their prey.

Although these tiny insects may not evoke nightmares of flashing teeth and claws, they do pose a serious and potentially deadly risk. That’s because they spread a smorgasbord of diseases.

A buggy perfect storm

Ticks and mosquitoes have been on my mind lately for a couple of reasons. One was the biannual “Bug Barometer” released by the National Pest Management Association in April. It predicted “a very buggy spring and summer” due to a mild winter and wet spring – an insect “perfect storm.”

The other was a recent flurry of news reports about the impact of climate changes on tick and mosquito behavior. Cold-blooded as they are, ticks and mosquitoes can’t move when temperatures drop near freezing. Like snowbirds, they prefer balmy climes.

Some experts warn that climate change will alter the environment in ways that will expand the geographic range of mosquito and tick species. And as they migrate, these unwanted guests will inevitably bring their disease baggage with them.

The greatest menace

The World Health Organization (WHO) has called mosquitoes “the greatest menace” of all disease-transmitting insects, attributing them with millions of deaths a year. Some people have gone even so far as to call them “the most dangerous animal on Earth.”

Mosquitoes do carry a long list of scary diseases. These include malaria, yellow fever, dengue fever, Chikungunya, Zika, and West Nile. Only the last one is transmitted by mosquitoes in Montana.

Of more than 3,200 species of mosquitoes worldwide, Montana harbors about 50. Among these are the Culex mosquitoes, which transmit West Nile. They lay their eggs in still water, including ditches, storm drains, wading pools, birdbaths, flowerpots, and abandoned tires. They emerge when temperatures reach the 70s and 80s and are most active at dusk and dawn. They usually stop biting when temperatures fall below 50 degrees at night.

West Nile virus is an erratic disease. Four out of five people who are infected have no symptoms. Others may develop West Nile fever, which is characterized by fever, headache, tiredness, and body aches. Less than 1 percent may develop a form of West Nile disease that can lead to coma, tremors, convulsions, paralysis and, sometimes, death.

Thirteen Montanans have died of West Nile virus since it first arrived in the state in 2002 (compared to two fatal grizzly attacks during the same period). The state health department confirmed three mild cases of West Nile just last week, in Bighorn, McCone, and Toole counties. Mid to late summer is a high-risk period for the virus.

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Other mosquito-transmitted viruses have been reported in the state, but they were acquired in other locations.

Fortunately, Montana is not home to the Aedes species of mosquito. It’s responsible for Chikungunya, yellow and dengue fevers, and Zika virus. A recent international epidemic of Zika has caused devastating birth defects, mostly in Latin America. A single case of Zika was reported in Montana last year, but the person was infected while traveling in another country.

Tricky ticks

Okay, we should probably set the record straight: ticks aren’t actually insects. They’re arachnids. Like spiders, they have eight legs – the better to latch onto our clothing as we pass by.

There are many species of ticks capable of transmitting more than a dozen illnesses. Montana ticks cause Rocky Mountain spotted fever, Colorado tick fever, and tularemia, or “rabbit fever.”

Ticks track us through our breath and body odors, body heat, moisture, and vibrations. They crouch on the tips of vegetation with their first set of legs outstretched, waiting to grab on and climb aboard. Like mosquitoes, ticks infect us when their saliva enters our skin as they feed on our blood.

The most common symptoms of tick-borne infections include fever and chills, aches and pains, rash, and fever of varying degrees. Some diseases, like Rocky Mountain spotted fever, can be fatal if not treated.

Although most tick-borne illnesses respond to antibiotics, they can be quite difficult to diagnose. Removing attached ticks properly and quickly can reduce the chances of being infected (see sidebar).

Some health experts fear that it’s only a matter of time before ticks that carry Lyme disease reach the Treasure State. In the past 30 years, the number of cases nationwide has more than tripled. It has spread northward all the way to Maine in New England and Minnesota in the Midwest.

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