Ehrlichiosis – is my dog at risk?

Ehrlichiosis is a bacterial infectious disease transmitted by ticks. It was named after its discoverer, the German physician Paul Ehrlich. The disease, also known as tick fever, is endemic in the tropics and subtropics, but also in the Mediterranean region. It is therefore important to be aware of it when traveling to southern destinations. Ehrlichiosis became known during the Vietnam War, when several German shepherd dogs belonging to American soldiers fell ill and died. German shepherds, Dobermans, and huskies are still particularly susceptible to this disease.

INHALT
Cause and origin Symptoms Diagnosis Treatment Forecast Prophylaxis How to remove ticks correctly
Cause and origin

The pathogen that causes ehrlichiosis is the bacterium Ehrlichia canis. It is transmitted to dogs by the brown dog tick (Rhipicephalus sanguineus). There are not yet any large populations of this tick species in Germany. However, climate warming is causing the ticks' habitat to steadily expand northward. In addition, brown dog ticks that have been introduced can survive and reproduce in heated rooms. Infections must therefore also be expected in Germany.

The tick transmits Ehrlichia to the dog through its saliva when it bites. Unlike Lyme disease, transmission can occur within three hours of the tick attaching itself. In rare cases, the pathogen is also transmitted via blood transfusions or contaminated cannulas. The Ehrlichia bacteria attach themselves to specific immune cells in the blood. They multiply there and travel with them to the lymph nodes, spleen, and bone marrow. The infection suppresses the function of the immune cells. They spread the pathogens further to the lungs, kidneys, and meninges.

Symptoms

A distinction is made between acute, subclinical, and chronic stages of the disease. After an incubation period of eight to 20 days, the first, mostly non-specific signs of the disease appear. These are very mild and often go unnoticed. This acute phase can be characterized by recurring fever, loss of appetite, apathy, breathing difficulties, swollen lymph nodes, muscle twitching, and hypersensitivity.

After the acute stage, which lasts about two to four weeks, the subclinical (latent) stage can last for weeks to years. In this phase, the animals show no clinical symptoms despite the persistent infection. During this phase, the Ehrlichia bacteria retreat to the spleen and bone marrow. Only slight changes can be detected in the blood count, such as a reduced number of white blood cells.

If the infection is not cured, the subclinical stage develops into the chronic stage. In many cases, ehrlichiosis is only diagnosed at this stage due to the now clear symptoms. The disease is therefore often referred to as a "silent killer." The reasons for the transition from the subclinical to the chronic stage are still unclear. The predominant symptoms include skin and mucous membrane lesions, nasal discharge, nosebleeds, fever, apathy, emaciation, central nervous system disorders caused by meningitis, coughing caused by pneumonia, eye infections, and generalized joint inflammation.

Diagnosis

In addition to the clinical picture, your dog's medical history is extremely important. If your dog has been abroad with you in the past, a blood test should be carried out immediately. Your vet's practice will have rapid tests available that can detect ehrlichiosis, heartworm disease, Lyme disease, and anaplasmosis at the same time.

Antibodies can be detected in the blood at the earliest one week and at the latest four weeks after infection. If the antibody test is negative but there is still strong suspicion, pathogen detection is carried out using PCR (polymerase chain reaction, a molecular biological test method). In the acute stage, ehrlichiosis can also be detected in a blood smear.

Treatment

As this is a bacterial infection, it can be treated effectively with a sufficiently long course of antibiotics. In some cases, several treatment intervals are necessary to completely eliminate the pathogen. Depending on the severity of the disease, further symptomatic treatment measures such as blood transfusions to stabilize anemia (= anemia) and bleeding tendency may be necessary. Your veterinarian will discuss the exact procedure with you individually.

Forecast

The prognosis depends greatly on the course of the disease and the extent of existing organ damage. In advanced cases where the bone marrow is already affected, the chances of recovery are poor.

However, if the infection is detected and treated early, there is a good chance of a complete recovery. Nevertheless, even after sufficiently long treatment and clinical improvement, relapses or secondary infections can occur. These worsen the prognosis again.

Prophylaxis

As there is currently no vaccine against ehrlichiosis, tick prevention is the most important preventive measure. You should check your dog for ticks after every outing and remove any that you find. Ehrlichia is transmitted relatively quickly from ticks to dogs. To prevent tick bites in the first place, tick prevention is recommended, especially when traveling to affected areas. Various tick repellents and killers are available. You can use collars or spot-on treatments (medication that is applied to the back of the neck), for example. As some dog breeds may have intolerances, be sure to consult your vet to find out which product is suitable for your dog.

How to remove ticks correctly

To remove the tick correctly and completely, always use tick tweezers or a tick card. Use these to grasp the tick as close to your dog's skin as possible. Pull the tick out slowly without twisting or squeezing it. If the tick is squashed or stressed by prolonged manipulation, it will release more saliva and pathogens. If the tick's mouthparts or head remain stuck in the skin after removal, this can lead to inflammation or allergic reactions.

Then thoroughly disinfect the bite area and your hands. Dispose of the tick by burning it or wrapping it in paper towels and crushing it. Alternatively, you can simply pin it between two strips of adhesive tape. Then dispose of it in the household waste. If you want to know whether the tick is infected with Ehrlichia or other pathogens, send it alive in a well-sealed plastic bag by post to a special laboratory.

Observe your dog for signs such as fever or fatigue over the next few weeks. If you suspect an infection, contact your vet immediately.