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Health Care, Healthcare, Public Health, Science

Everything You Need To Know About Tick-Borne Diseases

tick 3

For much of the country, spring has finally made it’s long-awaited arrival. With warmer temperatures and longer days, many of us will take advantage of the opportunity to enjoy our favorite outdoor activities. But be wary — humans aren’t the only creatures that like to get out and about at this time of year…

Singer Avril Lavigne found this out the hard way last year, when her 30th birthday was disrupted by the onset of Lyme disease, an illness that left her bedridden for 5 months.

“I felt like I couldn’t breathe, I couldn’t talk and I couldn’t move,” she said in an interview with People. “I thought I was dying.” Lavigne went on to explain that she believes she was bitten by a tick at some point in the spring.

Unfortunately, Lavigne’s situation is shared by many: In 2013, the Centers for Disease Control announced that Lyme disease may be up to ten times more common than previously thought, striking about 300,000 Americans each year.

This figure does not tell the whole story when it comes to ticks, however, as these small arthropods are capable of carrying a wide variety of other pathogens that can cause human disease.

So how worried should we be this spring and summer? I decided to dig into the evidence to find out. Here’s what you should know:

What are ticks?

Similar in appearance to both insects and spiders, ticks are actually a type of arthropod — invertebrates with jointed legs — that belong to the same class of arachnids as mites. As an external parasites, ticks feed purely on the blood of other creatures.

Some ticks will only feed on a particular type of animal, while others are far less selective and will happily feed on other creatures if their regular host animal is unavailable. Additionally, the feeding habits of ticks can also vary across the four stages of their life cycle: egg, larva, nymph and adult.

The lifecyle of a tick.

The lifecyle of a tick.

Ticks locate potential hosts by detecting breath, odors, body heat, moisture, vibrations and even shadows in some cases. As ticks are unable to fly or jump, they wait for hosts on the tips of grasses and shrubs in a position known as “questing.” When questing, ticks hold onto the grass or shrub with their back pairs of legs while their first pair of legs is outstretched, ready to climb onto a host when they brush past.

When feeding, ticks do not burrow into the skin. Rather, a tick will grasp the surface of the skin and insert its feeding tube. Some tick species will secure themselves further with barbs on their feeding tubes, or by secreting a cement-like substance.

Ticks can be very difficult to notice if you are not actively looking for them. Besides being quite small, ticks can also secrete saliva with anesthetic properties, numbing the area where the tick is feeding and preventing the host from feeling that the tick has attached itself.

Once attached, a tick will begin to feed. The amount of time taken to feed varies between species, but some ticks can take as long as several days to feed fully, after which they drop off of their host and prepare for the next stage of their life cycle.

While tick bites themselves can provide a small degree of discomfort, the real danger comes from the pathogens that some ticks carry. If feeding on a host animal with a bloodborne infection, ticks can ingest the pathogens along with the blood. These pathogens can then be transmitted to other hosts the next time a tick attaches itself to feed.

Lyme disease

The most common of all tick-borne illnesses is Lyme disease, a bacterial infection caused by the pathogen Borrelia burgdorferi. The classic symptom of this infection is a temporary bulls-eye-shaped rash that appears around the area of the bite, typically within 2-5 days.

However, not everybody who gets Lyme notices the rash, and some of the other signs of the disease resemble the flu: fatigue, fever, headache and chills (these symptoms are common to many tickborne diseases).  If left untreated, Lyme disease can spread through the body, affecting the heart, joints and nervous system.

As a bacterial infection, Lyme disease is frequently treated with antibiotics such as doxycycline or amoxicillin. If the disease is allowed to develop over a course of several weeks, patients may require the administration of intravenous antibiotics, depending on the severity of the disease’s progression.

Of course, not everyone who is on the receiving end of a tick bite ends up contracting Lyme disease. The risk of catching the infection depend on a number of factors, including the type of tick that has been encountered and the length of time it had to feed.

In the U.S., Lyme disease bacteria are only transmitted by blacklegged ticks, also known as deer ticks. Since ticks are not born carrying Lyme disease pathogens, they can only acquire the infection after feeding on an infected animal — typically a mouse. This is why larval deer ticks will not transmit these pathogens.

Lyme Distribution 2013Blacklegged ticks are concentrated in specific areas of the country. According to the CDC, most Lyme disease infections are found in these endemic locations:

  • North-central states, mainly Wisconsin and Minnesota
  • Northeast and mid-Atlantic areas, from northeastern Virginia to Maine
  • The West Coast, particularly northern California.

In 2013, 95 percent of confirmed Lyme disease cases in the U.S. were reported in just 14 states: Connecticut, Delaware, Maine, Maryland, Massachusetts, Minnesota, New Hampshire, New Jersey, New York, Pennsylvania, Rhode Island, Vermont, Virginia and Wisconsin.

Being bitten by a blacklegged tick in one of these states still does not mean you will end up with Lyme disease. In most cases a tick carrying the Lyme disease pathogens needs to be attached for at least 36-48 hours before the bacteria are transmitted — that’s why removing a tick promptly after being bitten can greatly reduce the risk of acquiring the disease.

Other ticks, other disease

The blacklegged tick can spread several other diseases to humans, including anaplasmosis, babesiosis, and Powassan virus, an emerging disease that appears to be on the move in the northeastern part of the country. Although it shares many symptoms with Lyme disease, Powassan virus differs in that there is no treatment currently available for it. According to Dr. Theodore Andreadis, of the Connecticut Agricultural Experiment Station, the virus typically causes more severe illness than Lyme disease and can even be fatal in some cases.

Powassan virus can also be transmitted much more rapidly than Lyme disease. “These ticks will transmit this virus when they feed within a matter of hours, whereas with Lyme disease, for example, ticks generally have to feed up to 2 days before they’re capable of transmitting it,” Dr. Andreadis told CBS New York.

Only 60 cases of Powassan virus have been reported in the U.S. over the past 10 years, most of which have occurred in the Northeast and Great Lakes region. In the past several weeks, ticks carrying the virus have been found in previously unaffected areas of Connecticut and New Jersey.

Tick_Life Stages

Different kinds of ticks are capable of carrying different pathogens, thereby increasing the geographical distribution of tick-borne diseases.

Of course, blacklegged ticks are not the only species of tick known to spread disease to humans: Across the U.S., a number of different species can be found that carry a variety of different pathogens potentially dangerous to humans.

The lonestar tick, found in southcentral and eastern U.S., can carry pathogens that cause diseases such as ehrlichiosis, southern tick-associated rash illness (STARI) and tularemia. Recent studies suggest that they may also transmit heartland virus.

The Rocky Mountain wood tick, found in the Rocky Mountain states at elevations of 4,000 to 10,500 feet, is also known to pose a danger to humans. These ticks can carry pathogens that cause Colorado tick fever, Rocky Mountain spotted fever (RMSF) and tularemia. RMSF can also be transmitted by the American dog tick and the brown dog tick, which are found in most parts of the country.

Soft ticks, which lack the protective plate of other types of ticks, can transmit diseases such as tick-borne relapsing fever (TBRF), reported in 15 states so far: Arizona, California, Colorado, Idaho, Kansas, Montana, Nevada, New Mexico, Ohio, Oklahoma, Oregon, Texas, Utah, Washington and Wyoming.

The massive geographical spread of tick-borne diseases demonstrates that the risk of transmission is present anywhere that the environment is suited to the ticks.

Preventing and treating tick bites

There are a number of precautions that can be taken to reduce the chances of a tick attaching, feeding and potentially transmitting an infection. When questing, ticks are most likely to be found in wooded and bushy areas, with high grass and leaf litter, so either avoid or be cautious in these types of environments.

Clothing can also provide some protection from ticks. Wearing long-sleeved tops can protect the arms, and tucking pant legs into socks and boots can prevent ticks from having easy access to legs. Repellents are also available that can be applied to both skin and clothing. Those containing 20-30 percent DEET (N, N-diethyl-m-toluamide) offer several hours of protection.

After being out in an environment that could be home to ticks, it is recommended that you conduct a full-body tick check, especially as it is hard to notice them without actively searching.

tick removal

Prompt removal of the tick is key in preventing transmission of any pathogens they may be carrying.

As stated before, prompt removal of ticks is crucial to reducing the risk of infection. Although specialized tick removal devices are available, a regular pair of fine-tipped tweezers is more than adequate.

Using the tweezers, grasp the tick as close to the surface of the skin as possible. With steady, even pressure, pull upwards. Twisting and jerking the tick can cause some of its mouth-parts to remain embedded in the skin. If this occurs, carefully attempt to remove the remaining parts with the tweezers.

Once removed, clean the affected area and your hands, and dispose of the tick by submersing it in alcohol, placing it in a sealed container or disposing of it down the toilet. Do not crush a tick with your fingers.

Ticks are most active in the warmer months, between April and September, so now is the time to be particularly wary of these questing bugs. Although ticks are capable of spreading harmful diseases, with proper caution they should not prevent you from being able to enjoy the great outdoors.

 

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