Why is the Department of Health including ticks in its surveillance plan and what is Lyme disease?

This Thursday, June 20, the third part of the National Vector-Borne Disease Surveillance and Control Plan, focusing on ticks, will be officially launched. The goal is to conduct hitherto untapped surveillance of diseases transmitted by these animals through case detection, management and control.

The goal of this plan is to better understand the incidence of Lyme disease, a tick-borne disease that, although rare, can cause serious consequences. At the same time, the goal is to better detect cases of Crimean-Congo hemorrhagic fever, a new disease that the arachnids also spread.

Given the situation, the Science Media Center (SMC) has created a guide with what you need to know and recommendations on how to protect yourself from the risk associated with its high incidence.

What are ticks?

These are parasitic mites—arachnids, not insects—that feed on the blood of mammals and birds. They range in size from three to five millimeters, although the size depends on the species, sex, age and, above all, whether they have eaten recently, since these animals can expand to more than ten times their size after consuming blood. Although there are hundreds of species, not all of them transmit diseases or bite people.

Why are they dangerous?

Ticks carry viruses, bacteria and protozoa that cause a variety of diseases, some of which are very serious and even life-threatening. These include tularemia, Lyme disease, tick-borne encephalitis, babeiasis and Crimean-Congo hemorrhagic fever.

From a long list, there are two diseases that are of particular concern in Spain. Lyme disease – due to lack of data, difficulty of diagnosis and the potential for serious consequences – and Crimean-Congo hemorrhagic fever – due to its severity and status as a new disease.

What is Lyme disease?

This is a disease caused by bacteria of the genus Borrelia and are transmitted by ticks of the genus Ixodus. It can affect various parts of the body such as the skin, heart, nervous system, joints and muscles. Its most characteristic symptom is the appearance of a target-shaped skin rash.

At an information day on the National Vector-Borne Disease Control Plan held on June 17, Lucia García San Miguel, regional director of the Center for Coordination of Health Alerts and Emergency Situations (CCAES), explained that this is the largest vector-borne disease. mites and the one that has the greatest impact: “It is not an infection that can be cured and that’s it, but after months the manifestations can continue to appear and can cause serious and disabling consequences for life, but it is very difficult to diagnose because there are no methods, “adequate”.

“It is a disease that, if assessed after the acute phase, is not at all easy to diagnose and these are indirect diagnoses with high suspicion but not at all obvious,” noted CCAES director Fernando Simon. The difficulty of confirming that symptoms are caused by Lyme disease has led to the use of untested diagnostic methods on some forums. “Then it is confirmed that in many cases this is not the case, but it is very difficult to tell someone with a very disabling disease that they do not have Lyme disease, and even more so when they are convinced that they have Lyme disease,” Simon added.

What is Crimean-Congo hemorrhagic fever?

This is a disease caused by a virus and transmitted by ticks of the genus Gialomma. Initial symptoms include fever, dizziness, vomiting, headache, eye and neck pain, and severe back and leg pain. The mortality rate can be as high as 40% and, unlike Lyme disease, which requires a tick bite, it can be transmitted between people.

This is a new disease in Spain, with 15 cases identified since 2016. “We believe it will grow,” says García San Miguel, coordinator of the National Plan. So far, most cases have been identified in Salamanca and western Extremadura, although it is possible that other areas may be under-detection because health workers are not expecting the disease.

When and where is the risk of being bitten highest?

“In the summer we expect almost all vector-borne diseases because that is when they are most active,” says García San Miguel. For this reason, the World Health Organization (WHO), together with the German Federal Center for Health Education (BZgA) and the European Center for Disease Prevention and Control (ECDC), included a warning about ticks in their guidance for participation in Euro 2024. which takes place in Germany.

“When outdoors, remember that ticks are most active from April to September. Ticks live not only in forests, but also in parks, gardens and backyards, wherever you enjoy football games or accompanying parties,” warns the guide, highlighting that these ticks can transmit diseases that cause serious chronic diseases such as Lyme disease or tick-borne encephalitis (TBI).

In Spain they are currently found mainly in rural areas. “In cities this is strange, and in principle there are no serious risks, but sporadically there may be cases when it is carried by an animal or a tourist,” Simon explained.

Which parts of Spain are at greater risk?

García San Miguel noted that Lyme disease is mainly concentrated in the north: in Asturias and Galicia, but it is also found in other autonomous communities. Therefore, the goal from now on is “monitoring throughout Spain.” “We have no idea exactly how many cases there are,” he admitted.

Something similar is happening with Crimean-Congo hemorrhagic fever: although most cases are concentrated in Salamanca and Extremadura, it remains to be seen whether there is under-detection in other places where cases are not expected to be found.

But are there more ticks than before?

In some areas of Spain, cases of tick bites have become more frequent. In the Valencian Community, for example, they have increased sixfold over the past five years. Perhaps climate change played a role, since the season for the appearance of these ticks has been extended due to temperatures, and they are already appearing a month earlier than usual: bites begin not in May, but in April.

Do I need to take special precautions when handling dogs?

Contrary to popular belief, the risk is not associated with dogs: these animals do not usually suffer from bites thanks to the collars they wear, and in any case, the species that transmit Lyme disease and Crimean Congo hemorrhagic fever do not affect dogs.

How can I reduce my risk?

“We have to go out on the field in long clothes, with socks over our pants, which is a little difficult for us in the summer, and we wear cooler clothes. It is very important when we return home to check ourselves and each other, because sometimes they are in places that are not visible,” concludes García San Miguel. Repellents can also be used.

It takes a tick several hours to start feeding, but only then does the risk of infection arise: if we find it on our body, but it has not “attached”, we can destroy it without much concern.

I found a tick sticking, what should I do?

García San Miguel explained that in case of a bite, “you can use tweezers with a blunt edge, but it is important to remove it by pulling upward.” If we don’t know or don’t want to do this, we should go to the medical center.

It is important to avoid other forms of traditional extraction (oil, cotton wool, scissors, heat, or even finger pulling) as they can spread pathogens the animal may have.

You should never wait for it to come off on its own, but rather remove it as soon as possible, as the risk of infection increases over time. It is also important to preserve the tick because it can be of great help to doctors and help in making a diagnosis in case of illness. It can be stored in a jar with damp paper.

I was bitten by a tick, how do I know if I need to see a doctor?

The risk of developing the disease after a tick bite is minimal, but if clinical manifestations occur, it is advisable to remain under observation for four weeks. In this case, it is necessary to consult a doctor – if this has not been done previously – to remove the animal.