VECTOR BORNE DISEASE 101: Lyme disease / Lyme borreliosis — a misfortune we blame on the tick Ixodes ricinus
- Katarina Anne Žumbar, dr.med.vet, CVA,CVFT,CFT,CTP,CHT,CPLC
- Oct 15, 2025
- 4 min read
Updated: Feb 13
Before I introduce you to this ZOONOSIS (zoonosis - diseases that are transmitted from animals to humans and vice versa), for which we have data that in a period of 5 years (research 2012-2016) 2470 people in the area of northern and continental Croatia fell ill, I have to thank a very dear person who "picked up" an infected tick this year in October, but did not immediately go to the doctor because, I quote: "I don't have time for that, the animals will not feed themselves" and "don't worry, not even the universe will let me die because there is no one else to take care of the animals" (she is a volunteer who works over 20 volunteer (unpaid) hours a week (at least 80 more per month) and has been doing so for a very, very long time..).
Who is Mrs. Borelia Burgdoferi?
A little about the history of the lady bacteria, Borrelia burgdorferi.
The disease was named after the town of Lyme in the American state of Connecticut when mothers (in the 1970s) began reporting a large number of cases of juvenile rheumatoid arthritis (that is, symptoms that doctors recognized as symptoms of JRA). Adults also became ill, and some of the most common symptoms were: swollen and painful knees, paralysis, skin rashes (urticaria), headaches, and severe chronic fatigue and weakness.
In 1982, Dr. Burgdofer finally connected the vector (vector=intermediary, in the case of Lyme disease in the USA it was the so-called "deer tick") and the causative agent (bacterium) with the symptoms, and in his honor the causative agent bears the second part of its name (Borrelia BURGDOFERI).
What are the symptoms in humans?
The previously mentioned research in Istria showed that out of 126 reported zoonotic diseases, Ms. Burgdoferi was responsible for as many as 93.4%.
On average, around 400 people fall ill annually in the entire Republic of Croatia, mostly in regions of Zagorje, Međimurje, Koprivnica-Križevci County, Zagreb and Zagreb County, and least in Istria. Women are affected somewhat more often, and in terms of age distribution, the most vulnerable categories are 0-9 years and 50+ years.
Not every tick is INFECTED, but it is important to:
Check yourself after your outdoors adventures, especially if you are not well-dressed and do not use repellents. Check your scalp, armpits and groin area especially carefully because it is harder to spot a small tick there (a female that has not yet sucked blood).
If you have a tick bite (you see an attached tick), you can remove it yourself or go to a doctor to have it done.
How not to remove a tick: do not oil it or squeeze it. This can lead to increased saliva secretion into our body, and saliva contains the pathogen.
To remove all sizes of ticks from our skin or the skin of dogs/cats, we use this practical set:
With these special tweezers (the size of the tweezers depends on the size of the tick), we grasp the tick in the area where the body contacts the skin and slowly turn the tweezers counterclockwise.
Our "human" tweezers that we have in our nail sets are not ideal because they have sharp metal tips and often tear off the tick without its head.
One of the first symptoms is a red rash that spreads - it can spread in a ring (literally acting like red rings or in the shape shown in the pictures below). Such a rash is called erythrema migrans.
If we do not seek medical help (the most ideal is to go to an epidemiologist), further symptoms are: fever and chills (similar to the flu), severe headache, fatigue and exhaustion, neck stiffness, enlarged regional lymph nodes and muscle pain.
Untreated Lyme disease has chronic consequences: arthritis (especially the knees), neurological symptoms (Bell's palsy), neck stiffness, severe headaches, problems with memory, speech and sleep, and heart rhythm disorders and inflammation of the heart muscle (myocarditis).
Lyme disease is treated with antibiotics and, if you see a doctor in time, the therapy is quick and successful.
What are the symptoms in dogs and cats?
Cats are mostly immune to B.Burgdoferi. In rare cases when they do catch the disease, the symptoms will be similar to those in dogs.
Most common symtpoms in dogs are:
Lameness and/or joint swelling
Elevated body temperature/fever
Anorexia and, if untreated, weight loss
Lethargy and general weakness
Swollen lymph nodes
The incubation period for Lyme disease can be long (up to 5 months). Incubation means that the causative agent of the disease is in the body, but we do not yet have clinical symptoms that would lead us to suspect the disease.
This means that you may not have seen a tick on your dog for a few months, but the dog may develop symptoms of the disease.
The above symptoms can also be symptoms of other diseases, so your veterinarian will make a final diagnosis and determine the appropriate treatment.
How can I protect my dog?
By diligently applying tick prevention, each month! Climate has changed, we no longer get long and cold winters so tick are out and about throughout the whole year!
Chose safe and proven prevention (and before buying read the label to see from what that product protects and what is the protection duration).
On how to recognise a quality product I will write sometimes later, but my personal recommendation for the past decade has been Effitix spot on which is a strong REPELLENT and ACARICIDE which is a win-win combo!
Conclusion
A little bit of humor harvested from a shelter volunteer who is always near the breaking point from stress and obligations:
Me: are you not afraid of sharing those photos (the ones above, with the rash) with me..I might upload them to Onlyfans?
She: If that is going to help me pay the vet bill for the shelter, be my guest!
Share your thoughts, comments and questions with us. And join our FB group: VetKat! Approved Veterinary Advice and Support group
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