The Lyme disease

During the last couple of years, multiple articles about the Lyme disease, an infectious disease spread by ticks has gotten Finnish people living at coastal areas very uneasy. Only a few people dare to be in the summery grass with bare legs.

- Even though there is no reason for panicking, a small fear of ticks is always healthy. Everyone should know how the disease spreads and the early symptoms. An infection in the early stages can be effectively treated with antibiotics, tells Jarmo Oksi, an internal medicine and infectious disease specialist in Mehiläinen.

Even though the Lyme disease has been newly “discovered”, it has been afterwards found out, that the disease has existed in Europe for at least a hundred years for a certainty. In the United States, the Lyme disease is the most common disease spread by insects and the prevalence of the disease has caused hysteria in some areas. Also, in Central Europe and in Sweden the disease is particularly prevalent.

- In Finland the Lyme disease occurs on the same areas, where there are ticks. The most cases have been identified in Åland and in the coastal areas of Southwest and South of Finland.

- It has been estimated, that about 3000-4000 people get sick with the early stage of Lyme disease in Finland every year. If the disease isn’t treated with antibiotics in the early stage, about half of the patients get posterior symptoms of the disease, estimates Oksi.

It is important to go to the doctor immediately after a tick’s bite if a circular expanding area of redness appears on the skin, which is a rash referring to a Lyme disease contagion.

Borrelia bacterium

Borrelia can transfer to the skin through a tick’s bite and sometimes, but rarely through a gadfly’s bite.

- The risk of borrelia transferring from the tick to the human’s skin, increases significantly when the tick has been attached to the skin for a day. The size of the tick is about 1-3 millimeters in its developing stages, but after sucking blood it can expand to be about 10 millimeters. Even though the tick’s proboscis is full of hypostomes, it can suck blood without getting detected, as numbing substances are secreted through the tick’s saliva. Against the usual belief, ticks don’t fall on people from alders, they live and move mostly among the undergrowth. Not all ticks are carriers of the borrelia bacterium.

- So far, the knowledge is, that the amount of these infectious ticks differs considerably in each area, tells Oksi.

Symptoms of the Lyme disease

If borrelia is left untreated in the early stages, it can spread from the skin to other places in the body. Symptoms can show up in one or more organs within a week, a month or even a year.

- The most common areas for the disease are the brain, nerves, joints, heart and skin. Joint problems appear on half of the patients, but a clear infection swelling the joints, known as arthritis develops only on every fifth patient.

- Typical for joint problems caused by the Lyme disease are fluctuating phases with symptoms or no symptoms at all. The symptoms may resemble rheumatism symptoms. Typically, only a few of the big joints, such as knee or ankle get sick.

Chronic Lyme disease

The most typical neurological symptoms caused by the Lyme disease are tearing pain and aches on the body and the limbs. They are caused by the bacteria nesting in the nerve roots, which leave from the spinal cord.

- The Lyme disease can also infect nerves, that leave straight from the brain, such as facial, optic and auditory vestibular nerves. Facial nerve paralysis is one of the most typical ways of how the neurological component of the Lyme disease occurs. Borrelia often causes meningitis, which may recur, but compared to other bacteria causing the disease it is milder and may have very little symptoms. Borrelia can also nest in the brain tissue itself.

The progression of Lyme disease

Heart symptoms develop on under 10 percent of the patients.

- They typically show up after a couple of months after the tick’s bite. Borrelia can cause a sudden bradycardia phase, which may even require a temporary pacemaker. The Lyme disease can also sometimes appear as a slowly progressing myocarditis.

- The Lyme disease differs from other bacterial infections in a way, that the progression of the disease is rarely very harsh. Moreover, the fact, that the infection can progress over the years while the patient lives relatively normally demonstrates this. The same person can get sick with the Lyme disease repeatedly. Even though the body might create antibodies, they don’t protect from the recurrence of the disease.

Examining the Lyme disease

The Lyme disease diagnosis is based on the information gotten from patient, as well as symptoms, which can be supported by laboratory tests.

- The patient is asked for information even from the past few years: the most important information is naturally whether the patient has lived in or visited tick areas, as well as tick bites and related rashes. The most common laboratory test to look for the Lyme disease is measuring the creation antibodies from the patient’s blood sample.

- Unfortunately, the creation of antibodies during the early stages of the disease is low and this examination only detects about one third of the cases. The early stage eryhthema migrans rash diagnosis is therefore done based on only its appearance. If there is no bite detected or there is no circular rash developed, the early stage Lyme disease will almost without exceptions be left untreated, reminds Oksi.

Lyme disease test for detecting antibodies

When the Lyme disease stays in the body for a longer time, antibodies have time to form. So, when diagnosing a later stage Lyme disease, the antibody examination has a crucial importance. If the patient has symptoms referring to the brain or nerves, the antibodies are examined from the spinal fluid as well as from the blood test.

- However, the biggest problem with the antibody examination is, that even though the test would be clearly positive, it cannot show for a certainty if the patient has an ongoing infection or are the detected antibodies a sign from an earlier infection, which has already been treated. Among with the antibody examination, cultivation and duplicating borrelia DNA can be used, but unfortunately, they are complicated and time-consuming examinations.

Treating the Lyme disease

Treatment of the later stage Lyme disease is aimed to be centralized in places, that are at the standard of central hospitals. The later stage Lyme disease is often treated with an antibiotic given through the vein and often the treatment is continued through the mouth.

- Even with long treatments, the symptoms may partly stay the same or come back after the treatment with some patients. Symptoms in the brain area can for example continue, because the tissue damage has already caused irreversible changes.

- The Lyme disease can also trigger an autoimmune reaction, when the body’s defense mechanisms cause damages in its own tissues. So, this is how the symptoms of the disease can continue to some extent, even though the borrelia has already been removed with antibiotics, mentions Oksi.

Lyme disease vaccine

There is no vaccine against the Lyme disease. More commonly it is known as the tick vaccine, the TBE vaccine, but it only protects from tick-borne encephalitis not from the Lyme disease. Sufficient clothing, inspecting for ticks and removing ticks from the skin immediately after finding them are ways to protect against tick bites.

Read more:

A tick's bite: how to remove a tick from the skin