Lyme disease in the dog
The Lyme disease the dog is the most common by tick bites transmitted disease of the dog . In addition to humans (→ Lyme borreliosis ), other mammals , especially dogs , can also contract Lyme borreliosis. Borrelia , the borreliosis pathogen, is transmitted through the bite of various types of ticks. In Germany, the common wood tick ( Ixodes ricinus ) is primarily responsible for the transmission of Lyme borreliosis. Sick dogs suffer from attacks of fever, joint pain, joint inflammation, muscle pain and lame forelegs and hind legs ( legs ). Lyme disease in dogs can also be severe and in the worst case fatal.
Pathogens
The causative agent of Lyme disease are bacteria of the genus Borrelia . The name was given in honor of the French bacteriologist Amédée Borrel (1867-1936). The most common Borrelia species in Germany bears the name of the Swiss scientist and discoverer of this species Willy Burgdorfer : Borrelia burgdorferi sensu stricto (Latin for 'in the narrower sense'). Borrelia are spiral-shaped, 10–30 μm small, gram-negative bacteria with linear DNA and belong to the order of spirochetes . Borrelia make rotating movements, similar to a corkscrew. During the infection process, they actively move from the intestine of the infected tick into the tissue of the host animal . This process takes about 24 hours.
distribution
Borrelia are the most common pathogens found in ticks in the northern hemisphere . In Germany the pathogen is widespread nationwide, but there are regional fluctuations. The proportion of infected ticks varies between 5 and 35%.
Infections are common in dogs. In one study, 5881 serum samples from randomly selected dogs were tested for antibodies against Borrelia. Depending on the region, 1.9 to 10.3% of the animals tested positive. Several Borrelia species have been documented as pathogens for dogs: Borrelia burgdorferi sensu stricto , Borrelia garinii and Borrelia afzelii . Multiple infections with different types of Borrelia are possible. The most common species in Germany is Borrelia afzelii. - it makes up 38% of the German Borrelia population , followed by Borrelia garinii (33%). About 18% of German Borrelia belong to the genospecies Borrelia sensu stricto . So far only infections with Borrelia sensu stricto have been experimentally detected in dogs , but there are case reports of infections with Borrelia garinii and Borrelia afzelii .
transmission
Lyme disease is transmitted by a tick bite. As carriers especially the play Common wooden support , more rarely other ticks, such as the fox tick a role. Dermacentor variabilis is also of concern in the United States . The Borrelia are initially in the intestines of the infected tick. This does not pierce the blood vessels directly , but presses its suction tube into the skin . The suction tube penetrates the epidermis , the upper layer of skin, and finally reaches the subcutaneous tissue, which is permeated with blood vessels. This cuts the tick with special tools that are located on the suction tube - the chelicerae . This causes blood to escape into the tissue, which she sucks in with her suction tube. The blood meal lasts for several days.
During the long act of sucking, the Borrelia migrate from the tick's intestine into its saliva and then into the dog's skin tissue and multiply there. The incubation period is from 2 weeks to 5 months. In dogs - as in humans - a circular, ever increasing inflammatory reaction can occur - the so-called wandering redness ( erythema migrans ).
Symptoms
Wandering redness is a key symptom that an infection with Borrelia has taken place and that the pathogens are spreading in the animal's body. The Borrelia multiply by dividing lengthways every 10–24 hours. But the migratory redness does not develop in all affected animals. Often it is also not noticed due to the fur and the stronger pigmentation of the skin. In the first stage of the disease, unspecific symptoms such as fever , fatigue, and reluctance to eat can appear. Some of the infected dogs have repeated episodes of disease as the disease progresses. The symptoms can vary and gradually increase. After weeks to months, dogs suffering from Lyme disease develop joint inflammation ( arthritis ), lameness in the forelegs and hind legs, fever attacks and muscle pain. In particular, if the disease is discovered late, it can be chronic despite treatment. Some studies suggest that dogs can also have symptoms of the heart , such as inflammation of the heart muscle ( myocarditis ) and atrial fibrillation . Fatal inflammation of the kidneys ( glomerulonephritis ) has also been observed in individual cases. However, Lyme disease in dogs can also be completely asymptomatic.
Diagnosis
Tick exposure is a prerequisite for infection . The diagnosis of Lyme disease infection in dogs is then based on clinical symptoms and serological tests.
Borrelia burgdorferi can be detected directly using the polymerase chain reaction or cultural detection. Evidence from blood, synovial fluid or liquor is only rarely successful. Detection from joint capsules, connective tissue, muscles, lymph nodes or the skin around the tick bite is not always possible, since only a small number or no bacteria have to be present in the tissue examined. The direct detection of the pathogen therefore plays a role primarily in determining the genospecies of the pathogen and less in establishing a diagnosis.
The diagnosis of Lyme disease can be made indirectly using serological tests: The blood of the animal is examined for antibodies of the IgG ( immunoglobulin G ) type . This is done with the help of the ELISA method (enzyme-linked immunosorbent assay). A special ELISA test (C6-ELISA) can only be used to detect those antibodies that occur in the event of an infection, but not in dogs vaccinated against Lyme disease. The C6 peptide is part of the protein Variable major protein-like sequence , expressed (VlSE), a surface protein of Borrelia that is only upregulated in the host and which is the most important virulence factor of the pathogen and is immunodominant. C6 antibodies appear 3 to 5 weeks after infection and persist for at least 12 months if not treated. If the test result is positive, the Western blot is used to continue testing to rule out false-positive results of the ELISA test. Even if the animal responds to antibiotic treatment within a few days , this can be further evidence of the diagnosis. Since there is no reliable evidence for the disease, other infectious pathogens, immune-mediated diseases or tumors should be excluded.
A urinalysis should also be done as Lymedisease nephritis (Lyme disease-associated protein loss nephropathy) can cause proteinuria .
Therapy and prophylaxis
Lyme disease in dogs is treated with antibiotics , usually doxycycline . The therapy lasts about 30 days, then the success of the therapy is checked by means of serological tests. If not all Borrelia have been killed, the veterinarian will initiate another treatment cycle. Any damage to the nerves that has already occurred can still persist and the symptoms take a chronic course.
One of the preventive measures is to prevent tick bites . For this purpose, special tick-repellent active ingredients ( acaricides such as Amitraz , Deltamethrin , Flumethrin or Permethrin ) can be used, whereby attention must be paid to intolerance due to a possibly existing MDR1 defect . Since Borrelia needs 24-72 hours to get from the tick's intestine to the tissue of its host , the early detection and removal of ticks plays an important role in reducing the risk of Lyme disease. Therefore, the dog should be checked thoroughly for ticks after each stay outdoors - and these should be removed as soon as possible. Fast-acting acaricides such as Afoxolaner and Fluralaner can therefore also be used prophylactically.
A Lyme disease vaccination is also available for dogs . The guidelines of the Standing Vaccination Commission for Veterinary Medicine (StIKo Vet.) Recommend vaccination for dogs from 12 weeks if there is an increased risk of infection. It can be vaccinated against three disease-causing Borrelia genospecies Borrelia burgdorferi sensu stricto , Borrelia garinii and Borrelia afzelii , either with individual vaccinations or with a combination vaccination. An effect via the Borrelia strains used in the vaccination is not to be expected, tick prophylaxis is also strongly recommended for vaccinated animals. The Lyme disease vaccination is classified by the StIKo Vet. As a non-core component , so it only makes sense to use it under special circumstances.
Individual evidence
- ↑ B. Chomel: Tick-borne infections in dogs - An emerging infectious threat. In: Veterinary Parasitology. 179, 2011, pp. 294-301.
- ^ RK Straubinger: Pathogens, transmission and prevention - Lyme borreliosis in dogs. In: kleintier.konkret. Issue 5, 2008, pp. 3–6.
- ↑ P. Schanilec et al: Clinical and diagnostic features in three dogs naturally infected with Borrelia spp. In: Acta Veterinaria Brno. 79, 2013, pp. 319-327.
- ↑ a b c d e B. Mehlhorn, H. Mehlhorn: Ticks on the advance! 1st edition. Düsseldorf university press, 2009, ISBN 978-3-940671-12-7 , pp. 53-55.
- ↑ a b c d e f K. Duchow et al: Guideline for the vaccination of small animals. In: Deutsches Tierärzteblatt. Garnish. Issue 7, July 2013.
- ↑ a b L. Adaszek et al: The diagnose of Borrelia afzelii infections in dogs. In: Ann. Univers. Lublin. Poland 64, 1, 2009.
- ↑ a b c R. K. Straubinger, N. Pantchev: The Lyme borreliosis vaccination in dogs - controversial. In: kleintier.konkret. 5, 2010, pp. 8-11.
- ↑ a b c Nikola Pantchev et al .: Tick-borne diseases in dogs in Germany - Part 2: Borreliosis, anaplasmosis, babesiosis: diagnostics. In: Kleintierpraxis , Volume 63, Issue 6, 2018, pp. 340–358.
