Lyme disease is a zoonotic disease (infection from animals to humans), caused by the bite of a tick infected by bacteria. This pathology is composed of a clearly inflammatory, multisystemic process, whose identification is achieved by skin lesions that slowly increase in size, which are characterized by having an annular shape, known as chronic erythema migrans, associated with fever, presenting myalgia (muscle pain), in turn arthralgia (joint pain), headache (headache), fatigue and lymphadenopathy (swollen glands).
How is Lyme disease spread?
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Lyme disease is transmitted through the tick, the most common being the deer tick or also known as the deer tick. However, it is important to clarify that not all deer ticks are carriers of the bacteria that cause this disease.
These small animals can become infected by ingesting animals that contain said bacteria and in turn transmitting it to humans through the bite, at the same time that it remains attached to the person for at least 36 hours. It should be noted that Lyme disease cannot be transmitted from person to person, as well as it is rare that it is transferred from the mother to the fetus.
If not treated in time, more than half of the patients progressively develop neurological complications, heart, paralysis and chronic rheumatoid arthritis. Lyme disease is also known by the following names: Lyme Borreliosis and Meningopolineurite by ticks.
Lyme is more common in the regions of the USA, however, cases have also been known in Europe, Australia and Asia, this pathology can affect people of all age groups, to date there are no data of preference for a specific age group, but if a higher incidence is observed between the months of May to November, with a maximum predisposition in June and July, especially in the northeastern and midwestern states of the United States. The risk of infection decreases exponentially after the fourth decade.
Etiology of Lyme disease
The bacterium that triggers this pathology is known as Borrelia spirochete Burgdorferi, the vector responsible for its transmission is the Ixodes tick, belonging to the genus Dammini pacificus, and Ixodes scapularis. Studies have been done that show that Lyme disease is the product of the direct action of infection and the immune response to Borrelia burgdorferi.
This pathology is also known as tick disease or borreliosis. In North America it is caused by the aforementioned bacterium, Borrelia Burgdorferi, while in Europe and Asia, in addition to said bacterium, there are two other varieties that can produce it, and they are Borrelia garinii and Borrelia afzelii.
In North America and Europe, the tick disease is the most frequent caused by the bite of this animal. Being its time of greatest incidence during the summer.
The first case of this chronic skin disease described was in 1883. At the beginning of the 20th century, the first texts on neuroborreliosis were published. Over the years the name of borreliosis was put aside, this thanks to a series of cases that developed in the town of Lyme in the state of Connecticut in the United States in 1975.
Generally, the ticks that carry this bacterium are usually hosted by wild deer or deer, as well as wild rodents. Dogs that frequent wooded areas can also acquire these small mites, and can even develop the disease. However, the dog is not capable of transmitting Lyme disease, but it is possible that the ticks that it possesses, change host and move to humans.
According to experts, since the 1980s the number of cases of borreliosis has been increasing, which is due to climate change that in recent times has been drastic, causing the population density of ticks carrying the bacteria to increase., at the same time that it causes their geographic distribution to be much larger. The greater the number of ticks, the greater the probability of being bitten.
There may be thousands of cases of borreliosis that go undiagnosed. Between 2005 and 2014 in the United States there were more than 200 thousand registered cases, however, the figures indicate that annually around 300 thousand people are diagnosed with the tick disease. Meanwhile in Europe, registered cases have exceeded 350 thousand in the last two decades. In Russia, Central Asia, Mexico, Canada and China there is also a record of cases, although to a lesser extent.
Lyme disease symptoms
After the incubation period (which can be from 3 days to 1 month) an infectious picture may appear with the presence of pain in the muscles, fever, headache, pain in the joints and fatigue.
Lyme symptoms can occur both in the initial localized stage and in the disseminated stage of the disease. The symptoms that usually characterize tick disease can be divided into three stages, which are described below.
Stage 1: localized infection in early stage
In 3 of 4 patients appears what is known as erythema migrans, which is a spot color, red sprouting in the area where the tick stung. As the hours go by, this spot expands acquiring the shape of a halo, with red ends and a little lighter in the center, usually it has a diameter of 5 centimeters, but can reach 20 centimeters in diameter and it can be present for several weeks. It usually occurs on the thighs, armpits, and English. Apart from this, the erythema may be accompanied by numbness in the area, itching and a feeling of warmth in the affected area.
Stage 2: early scattered infection
- It can appear in a few weeks or even months after the bite occurs, and may be the first manifestation of the pathology. Apart from non-specific symptoms, skin lesions may appear, similar to migrating erythema, this through spirochetes spreading through the blood.
- Neurological disorders: myelitis, radiculoneuritis, lymphocytic meningitis.
- Pains in the joints and muscles in a migratory way.
- Cardiac disorders: atrioventricular obstruction, myopericarditis.
Stage 3: persistent infection
- It can appear months or years after the infection, since in its initial stages it was not completely cured.
- Presence of chronic or transient arthritis in one or more large joints, especially in the knees.
- Typical neurological picture: chronic encephalomyelitis or chronic polyneuropathy.
- Pain in the limbs, disorders in cognitive ability, tiredness.
In addition to the aforementioned Lyme symptoms, there is a condition known as “ post Lyme syndrome ”, in which different health problems occur, such as extreme fatigue, muscle pain, headache, cognitive alterations, difficulty concentrating, among others, which can occur even if the disease was treated correctly.
Lyme disease treatment
Antibiotics are used, generally the faster the treatment is applied, the faster and more effective reception will be. Antibiotics can be of different types.
- Intravenous antibiotics: they are generally applicable when the disease affects the central nervous system, they are usually applied for 15 to 30 days. They are effective in eradicating the infection, however, it may take longer to overcome symptoms.
These types of antibiotics can have side effects, including severe or mild diarrhea, low levels of white blood cells, infection by other organisms that are resistant to these drugs and are not related to Lyme.
- Oral antibiotics: it is the most common treatment for this pathology in its initial phase. Doxycycline is generally prescribed for children over 8 years of age and adults, for younger children cefuroxime or Amoxicillin is usually prescribed, as well as for women who are pregnant or breastfeeding.
This Lyme treatment is usually administered for a period of between 15 and 20 days, however, there are studies that indicate that cycles of 10 to 15 days are just as effective.
After treatment, it is possible that in a minority percentage, there are still some symptoms such as fatigue and muscle pain, which is known as Lyme post-treatment syndrome and of which the cause is unknown, however in this case, the treatment with more antibiotics is not effective. According to experts, this is because there are individuals who are more likely to develop an immune response, which contributes to the appearance of symptoms.
Lyme Disease in Dogs
Lyme Borreliosis is one of the most common diseases in dogs transmitted by the tick. The most frequent clinical feature is the canine's lameness when walking, since the joints become inflamed, another symptom can be depression and loss of appetite. Among the most serious complications are heart disorders, kidney disease or pathologies associated with the nervous system.
With regard to lameness, it can be recurrent, however, there are cases in which it is more acute and remains for 3 or 4 days, appearing again a few weeks later in the same area.
In some cases, kidney problems may occur, which, if not treated correctly, can cause glomerulonephritis, which in turn generates inflammation and dysfunction accompanying glomerulonephritis of the kidneys. As kidney failure progresses, the dog will show other symptoms such as diarrhea and vomiting, weight loss, increased thirst and urination, accumulation of fluid in the abdominal area and in the tissues.
Recommendations to avoid Lyme disease
To avoid the development of Lyme borreliosis, the main thing is to avoid a tick bite in endemic areas of this disease, especially in summer and spring. So it is recommended to use repellent, high boots, wear light clothing and gloves. Likewise, environmental control measures can be implemented, such as cutting the vegetation of the areas inhabited by people, using pesticides.
After having been in areas with the presence of Lyme cases, the body should be checked to certify that there are no ticks on it or on clothing, or failing that, bites. In case of finding a tick, it is important that it be removed correctly, with special tweezers to later disinfect the area. It is recommended to administer a dose of doxycycline for two days to prevent the disease from developing.
