Sometimes serious threats come in small packages. Ticks are a grave danger to humans and other mammals as they carry many diseases. It is increasingly apparent that one breed, the Lone Star tick, can cause an allergy to red meat. Ticks present an imminent threat to anyone who spends time in the outdoors.
Ticks are small arachnids, related to mites, within the order Parasitiformes. There are 900 species of tick divided into three groups. The Nuttalliedae from Southern Africa, is the only species in its family. Hard and Soft Ticks live in hot, humid areas worldwide.
A tick’s body has two primary parts. The Capitulum consists of the head and mouthparts. The Idiosoma contains the legs, digestive tract, and the reproductive organs.
Because they feed only on blood, ticks have specifically developed mouthparts. Between the palps common in arachnids is the hypostome. This is a calcified structure near the mouth area that ticks utilize to anchor themselves to the host. They then inject an anticoagulant into the host to help the flow of blood.
Ticks have eight multi-segmented legs. They use their rear six for locomotion. The first set’s tarsus also contains a unique organ known as the Haller’s organ. Ticks utilize this complex sensory organ to detect scent, humidity, temperature, and Carbon Dioxide. They are utilized to discover new hosts as they move past them.
Since ticks can neither jump nor fly, they hunt for a new host through “Questing ”. The tick will hold on to a blade of grass or a leaf and extend their first set of legs. The Haller’s organ helps them detect their preferred host. When a potential host walks within range the tick grabs on and attaches to feed.
Although some tick bites can be painful, most are not felt. This is why it is important check yourself after spending time in their habitats. They generally try to find a place to attach that is out of the way and hard to get at. Folds of skin, in the hair and on the back of joints are common places to look. If you have long hair it is important to check thoroughly because their size makes them easy to miss.
Feeding is an essential element in the life cycle of a tick. Each breed of tick has a different cycle from larva to adult, but they all need feeding before they can molt into the next life stage. They feed only on blood and this renders them aggressive in the search for a host.
In the United States, ticks are at the root of a variety of bacterial and viral diseases. They can also be carriers for protozoa that cause numerous health issues. The following is information from the CDC website:
Anaplasmosis is a disease caused by the bacterium Anaplasma phagocytophilum. It was previously known as Human Granulocytic Ehrlichiosis (HGH) and has more recently been called Human Granulocytic Anaplasmosis (HGA). Of the four distinct phases in the tick life-cycle (egg, larvae, nymph, adult), nymphal and adult ticks are most frequently associated with transmission of anaplasmosis to humans. Typical symptoms include: fever, headache, chills, and muscle aches. Usually, these symptoms occur within 1-2 weeks of a tick bite. Anaplasmosis is initially diagnosed based on symptoms and clinical presentation, and later confirmed by the use of specialized laboratory tests. The first line treatment for adults and children of all ages is doxycycline. Anaplasmosis and other tickborne diseases can be prevented.
Babesiosis is caused by microscopic parasites that infect red blood cells. Most human cases of Babesia infection in the United States are caused by the parasite Babesia microti. Occasional cases caused by other species (types) of Babesia have been detected. Babesia microti is spread in nature by Ixodes scapularis ticks (also called blacklegged ticks or deer ticks). Tickborne transmission is most common in particular regions and seasons: it mainly occurs in parts of the Northeast and upper Midwest; and it usually peaks during the warm months. Babesia infection can range in severity from asymptomatic to life threatening. The infection is both treatable and preventable.
Ehrlichiosis is the general name used to describe several bacterial diseases that affect animals and humans. Human ehrlichiosisis a disease caused by at least three different ehrlichial species in the United States: Ehrlichia chaffeensis, Ehrlichia ewingii, and a third Ehrlichia species provisionally called Ehrlichia muris-like (EML). Ehrlichiae are transmitted to humans by the bite of an infected tick. The lone star tick (Amblyomma americanum) is the primary vector of both Ehrlichia chaffeensis and Ehrlichia ewingii in the United States. Typical symptoms include: fever, headache, fatigue, and muscle aches. Usually, these symptoms occur within 1-2 weeks following a tick bite. Ehrlichios is diagnosed based on symptoms, clinical presentation, and later confirmed with specialized laboratory tests. The first line treatment for adults and children of all ages is doxycycline. Ehrlichiosis and other tickborne diseases can be prevented.
Lyme disease is caused by the bacterium Borrelia burgdorferi and is transmitted to humans through the bite of infected blacklegged ticks. Typical symptoms include fever, headache, fatigue, and a characteristic skin rash called erythema migrans. If left untreated, infection can spread to joints, the heart, and the nervous system. Lyme disease is diagnosed based on symptoms, physical findings (e.g., rash), and the possibility of exposure to infected ticks. Laboratory testing is helpful if used correctly and performed with validated methods. Most cases of Lyme disease can be treated successfully with a few weeks of antibiotics. Steps to prevent Lyme disease include using insect repellent, removing ticks promptly, applying pesticides, and reducing tick habitat. The ticks that transmit Lyme disease can occasionally transmit other tickborne diseases as well.
Rocky Mountain spotted fever (RMSF) is a tickborne disease caused by the bacterium Rickettsia rickettsii. This organism is a cause of potentially fatal human illness in North and South America, and is transmitted to humans by the bite of infected tick species. In the United States, these include the American dog tick (Dermacentor variabilis), Rocky Mountain wood tick (Dermacentor andersoni), and brown dog tick (Rhipicephalus sanguineus). Typical symptoms include: fever, headache, abdominal pain, vomiting, and muscle pain. A rash may also develop, but is often absent in the first few days, and in some patients, never develops. Rocky Mountain spotted fever can be a severe or even fatal illness if not treated in the first few days of symptoms. Doxycycline is the first line treatment for adults and children of all ages, and is most effective if started before the fifth day of symptoms. The initial diagnosis is made based on clinical signs and symptoms, and medical history, and can later be confirmed by using specialized laboratory tests. RMSF and other tickborne diseases can be prevented.
Borrelia mayonii is the proposed name for a new bacteria species recently found to cause Lyme disease in six people who live in the upper Midwestern United States. Worldwide, Lyme disease is caused by three main species of bacteria: Borrelia burgdorferi, B. afzelii, and B. garinii. Borrelia burgdorferi causes Lyme disease in the United States, while the other two species are the leading causes of Lyme disease in Europe and Asia. Borrelia mayonii is a new species that is genetically distinct from these three species and is the only species besides B. burgdorferi shown to cause Lyme disease in North America. Regardless of the bacteria’s species, the illness is still called Lyme disease or Lyme borreliosis.
Borrelia miyamotoi is a species of spiral-shaped bacteria that is closely related to the bacteria that cause tick-borne relapsing fever (TBRF). It is more distantly related to the bacteria that cause Lyme disease. First identified in 1995 in ticks from Japan, B. miyamotoi has since been detected in two species of North American ticks, the black-legged or “deer” tick (Ixodes scapularis) and the western black-legged tick (Ixodes pacificus). These ticks are already known to transmit several diseases, including Lyme disease, anaplasmosis, and babesiosis.
Colorado tick fever (CTF) virus is spread to people through bites of infected ticks. People who live in or visit areas in the western United States or western Canada that are 4,000‒10,000 feet above sea level may be at risk of becoming infected. Most cases of CTF occur during spring and summer months when ticks are most active. The most common symptoms of CTF are fever, chills, headache, body aches, and feeling tired. There are no medications to treat or vaccines to prevent CTF.
Heartland virus belongs to a family of viruses called Phleboviruses. Viruses in this family are found all over the world. Some of these viruses can cause people to get sick. Most of the phleboviruses that cause people to become ill are passed through the bite of a mosquito, tick, or sandfly.
Powassan (POW) virus is transmitted to humans by infected ticks. Approximately 75 cases of POW virus disease were reported in the United States over the past 10 years. Most cases have occurred in the Northeast and Great Lakes region. Signs and symptoms of infection can include fever, headache, vomiting, weakness, confusion, seizures, and memory loss. Long-term neurologic problems may occur. There is no specific treatment, but people with severe POW virus illnesses often need to be hospitalized to receive respiratory support, intravenous fluids, or medications to reduce swelling in the brain.
A rash similar to the rash of Lyme disease has been described in humans following bites of the lone star tick, Amblyomma americanum. The rash may be accompanied by fatigue, fever, headache, muscle and joint pains. This condition has been named southern tick-associated rash illness (STARI). The cause of STARI is not known.
Relapsing fever is bacterial infection characterized by recurring episodes of fever, headache, muscle and joint aches, and nausea. It is caused by certain species of Borrelia spirochetes. Tick-borne relapsing fever occurs in the western United States and is usually linked to sleeping in rustic, rodent-infested cabins in mountainous areas. Louse-borne relapsing fever is transmitted by the human body louse and is generally restricted to refugee settings in developing regions of the world.
I have included links to the full pages on the CDC website that go into greater detail on each of these illnesses. You should give each one of them a read to gain a better understanding of these threats.
There is another issue that is becoming better understood. The Lone Star Tick is common in the Southeast through Texas and is known to cause an allergy to red meat. When the Lone Star tick feeds on a mammal other than a Human or an Ape it comes in contact with a carbohydrate called Alpha-gal.
This carbohydrate is not naturally found in humans so when the tick attaches to a person any residual Alpha-gal that the tick is carrying can be injected. When the carbohydrate is identified by the body’s defenses build anti-bodies to it. These anti-bodies are the cause of the allergy.
Ohio State University estimates that the transmission of diseases begins after about 24 hours. It is important to find and remove the tick to reduce the chance to contract one an illness. There are several ways to remove ticks. If you have tweezers you use them to grip the tick as close to head as possible. You then pull the tick out, being sure to remove the head. There are also a number of brands of “tick keys”, metal devices that are designed to properly grip and remove the tick with ease.
You will also find a number of techniques around the internet and in various survival and first aid manuals, such as covering the tick in nail polish or petroleum jelly to suffocate the tick into self-removing. I personally have had little success using them, but have had other people report success using them.
The transmission of disease and the meat allergy caused by the Lone Star tick, and possibly others, make ticks a cause for concern. You can avoid ticks by being cautious in their habitats and staying out of high grass and leaf litter. A 20% to 30% solution of DEET can be used on the skin and a .05% of Permethrin can be used on clothing will act a repellent. Rose Geranium oil is also reported to be an effective repellent.
The Center for Disease Control has an excellent page on these illnesses. If you are going to spend any time in the woods, you should check it out to get up to date information. Be sure to keep your eyes open for upcoming blog posts that describe the various types of ticks that are native to the United States.