With climate change and milder winters, the ticks are expanding to new geographical areas where they couldn’t survive previously. And with them, the bacteria of the Borrelia burgdorferi sensu lato group, responsible for the infection transmitted by tick bite are also expanding and are transferring Lyme disease.
The increase in warm temperatures globally alters the functioning of ecosystems, and, in the case of ticks, this is no exception. Mild winters and long summer seasons make them active earlier than usual, in unexpected places and with larger populations.
The heat, for example, enhances the reproduction and expansion of small mammals, which are natural reservoirs of the Borrelia burgdorferi bacterium and, at the same time, hosts of the ticks that transmit the infection to humans. The temperature also affects the movements of migratory birds, another means of transport for ticks. Since numerous birds of the south move towards the north to breed, they just advance the migration of the ticks.
Lyme Disease The New Epidemic Of The 21st Century
Lyme disease affects humans since ancient times. However, the new environmental conditions and the greater awareness of this pathology and its risk factors, have now become a relevant public health problem. Today, Lyme disease is one of the diseases transmitted by vectors with greater growth in the West. It goes to the point of calling it the new epidemic of the 21st century!
In recent years, its incidence has multiplied by 25 in the US alone, with an estimated 300,000 new cases each year. The numbers for Europe show a notable increase in documented cases, which exceeds 360,000 in the last 20 years. In the United Kingdom, cases have multiplied by 10 since 2001. And the incidence in Asia also increases.
In Spain there are no official estimates of the number of annual cases. But, because Borrelia is widespread throughout Europe, extrapolating the data could be between 40,000 and 50,000 cases per year.
In the endemic areas of Europe, Borrelia burgdorferi bacteria circulate among the Ixodes ricinus ticks and larvae, widely distributed in the Iberian peninsula on many small mammals and birds.
Adult ticks generally feed on larger animals like deer and sheep. Even though these are not competent for Borrelia, they help maintain the reproductive phase of ticks. And when they jump to another host, such as a human, they transmit the infection through their sting.
What Is Lyme Disease?
As explained by the International Lyme and Associated Diseases Society, Lyme disease or Lyme borreliosis, is a multiorgan disease with mainly dermatological, rheumatic, neurological and cardiac manifestations. They call it ‘The Great Imitator’ because it can be confused with other diseases. Some of those diseases are Amyotrophic Lateral Sclerosis, Multiple Sclerosis, Chronic Fatigue Syndrome, Fibromyalgia, Alzheimer’s or Parkinson’s Disease. A fact that makes it difficult to diagnose and administer correct, timely treatments with antibiotics. This further increases the possibility of causing severe chronic complications in the joints, heart, and nervous system.
Given that there is currently no effective vaccine to protect people against Borrelia burgdorferi, prevention is mainly based on avoiding tick bites. Also, people need to be alert to possible symptoms after an exposure in endemic areas.