Lyme disease – some of you might have heard of it, maybe even caught it once or twice during a hike – is a nasty bacterial infection carried by fluid-feeding parasites such as ticks or horse-flies. I’m part of the unlucky ones who got it – I’m currently under treatment. Hopefully, I’ve had all the recognisable symptoms from day one, so the diagnosis was easily made. Being affected by it, I did some research to answer to the basic questions I had. Here are the answers I found, which I hope will be as useful to you as they were to me.
What is Lyme disease, and how is it transmitted?
Lyme disease, otherwise known as Lyme borreliosis, is an infectious disease caused by bacteria of the Borrelia genus. It was first identified in the US in the 1970s and studied in the 1980s, but some symptoms were found in archives back from the 19th century. Three different species of bacteria, found in different areas of the globe, can cause the disease.
Lyme is a zoonosis disease, meaning it is transmitted to humans by ticks which fed on a reservoir – mostly rodents bit by a nymph (a baby tick). Not all ticks transmit Lyme disease. The longer an infected tick stays on a host, the more probable the host will be contaminated. Nymphs are harder to see because of their tiny size, thus allowing them to stay secretly on a host for days. Ticks feed in spring and summer, so watch out for those especially during those seasons – coincidentally, it’s when we humans enjoy outdoor activities the most.
How do I know I’m infected?
The first clue is finding a tick sucking on your body, remembering seeing one or removing one.
The second clue is showing one or more known symptoms, but an infected person can go asymptomatic for months or even years before showing any signs of the disease.
There are three stages of the disease, and to each its symptoms. The most common symptoms for stage 1 (1 to 30 days after a bite) are a red, expanding rash called erythema migrans and flu-like symptoms (fever, chills, muscles and joints pain, swollen nodes). Symptoms for stage 2 (days to weeks after the bite) include additional rashes on the body, facial palsy, headaches, meningitis, joints pain and heart problems. Stage 3 (months to years after the bite), called chronic Lyme disease, is often misdiagnosed due to the wide range of symptoms that resemble to other diseases, such as arthritis, neurological problems, cardiac problems, and so on.
What do I do if I’m infected?
The first thing if to remove the tick using the proper tool, disinfect the area and to immediately seek a doctor (even if you show no symptoms, it’s good to have a professional check that you properly removed the tick). Do not use tweezers, or rub any alcohol or other products on the tick as this can push its stomach content into your skin and transmit the disease. Keep the tick in a jar to show it to your doctor.
If you have any doubt, seek medical help. Even if the rash you have is just an allergic reaction to a mosquito bite, or if those flu-like symptoms are just a summer bug, it’s better to be safe than sorry.
If you are indeed infected – and only a doctor can confirm that – you will be treated with antibiotics for a few weeks. If you are in stage 1 or 2, no blood test seem to be able to detect the disease as your body won’t have made enough antibodies yet, so trust your doctor if he tells you it’s Lyme disease. Never take antibiotics without medical supervision as Lyme disease symptoms resemble many other common diseases.
Why do ticks even exist?
Why do humans exist? Because they do. Every specie on Earth is part of the biodiversity, and each as a role. It’s easy to understand that one’s parasite is another’s host or food. We see ticks as a parasite, but Borrelia uses ticks as a host and a way of spreading, while birds and other insectivores see ticks as food (although it seems that guinea fowls greatly enjoy eating them). It’s a symbiotic relationship.
In the big scheme of things, parasites such as tick play an important role in population control when transmitting a disease or not. In this article, Pr Claude Combes, a French biologist, explains how useful ticks are using the antelope as an example. In the wild, an antelope spends 30% of its time cleaning itself, controlling its tick demography. What happens if the antelope get rids of all its ticks? It will then have more time to eat, get bigger and reproduce more. Lions would be happy to have more food around: the antelopes being fatter, they’d run slower and would be easier to catch and eat. So which benefits from the ticks disappearance? Antelopes or lions? One thing is certain: the fragile equilibrium between preys and predators would be greatly changed.
Ticks are also a good indicator of an animal’s health, as ticks like to feed on weak or sick hosts. They also are a good indicator of one ecosystem’s health: ticks population and distribution are a way for ecologists to determine whether an area is populated by healthy hosts or not (remember ticks like to feed on various species). If the tick population decreases, it could mean that there are less suitable hosts for them to feed on, meaning an overall decrease of animal population in the area. On the other hand, if the tick population increase, it could mean that there are more suitable hosts for them to feed on, meaning the ecosystem is stable or thriving.
Still not convinced of ticks’ usefulness? We humans can use ticks to our benefits. How? Ticks secrete an anticoagulant substance once attached to a host so that i can feed for days on. Tick anticoagulant peptide (TAP) was identified and scientists concluded in the ’90s that TAP could be developed for therapeutic means as a highly specific anticoagulant capable of treating occlusive vascular diseases. A protein in ticks’ saliva is also being tested as a treatment against asthma. How cool is that?
Why is Lyme spreading?
Recent articles about Lyme disease show a spread of the disease in North America and Europe. What’s going on? The explanation probably resides in multiple factors.
Climate change, as you’ve probably heard, means that the globe is getting warmer, at least where most ticks live. The gradual increase of temperatures in Europe and North America seem to be a good thing for ticks as it means they can migrate to higher altitudes and latitudes without freezing to death, or lacking hosts to feed on and reproduce. If you’re not happy about those news, you should also know that ticks will probably disappear from areas that become too hot or dry.
Humans’ doings such as forest fragmentation, urbanisation, and so on mean ticks and their hosts concentrate in shrinking natural areas. Statistically speaking, the chances of being bit by a tick increase if you take a stroll in such places.
Pathogen mutation has been identified by Dr Luft as a possible cause of Lyme spreading. A clone seem to be much more virulent than the original bacteria in both Europe and North America. Trans-oceanic migration means the same clone is now found on both continents.
This spreading of Lyme disease means it is urgent to teach populations and medical staff to identify the early stages or the disease and to properly treat it. Lack of knowledge or access to proper treatment means more and more infected people reach phase 3 of the disease without knowing it. There is no need to go on war against ticks, but it is important to know that they exist and to be careful should you be exposed to conditions which makes you a suitable host.
For more information, visit the CDC website or talk your doctor about it!