Tularemia is a highly contagious infection that occurs very rarely in Germany and can be transmitted to humans by mammals. Because of the plague-like course and the predominant occurrence in wild rabbits and hares, it is also referred to as rabbit plague.
What is tularemia?
Tularemia is caused by the bacterium Francisella tularensis, accordingly, it is a bacterial infection. Since the disease is transmissible from small mammals to humans, this is called a zoonosis. In Germany, the disease is very rare, the predominant occurrence is in northeastern Europe, Asia and North America. Depending on the site of entry of the pathogen, different manifestations of tularemia occur. The clinical picture may vary depending on the site of entry of the pathogen, some examples are:
Ulceroglandular tularemia: ulceration at the site of entry as well as sudden fever.
Glandular tularemia: swelling of the lymph nodes
Abdominal tularemia: typhoid-like clinical picture, swelling of the spleen and liver, diarrhea and pain in the abdomen (organs of the abdominal cavity are affected)
Intestinal tularemia: abdominal pain and diarrhea, vomiting, and nausea
Causes
The underlying cause of tularemia is bacterial infection with Francisella tularensis. Ticks, fleas, and lice can serve as reservoirs for the bacterium, and it is also capable of surviving in frozen rabbit meat for up to three years. Parasites carrying the pathogen can transmit the bacterium to both humans and mammals through a bite. Other routes of infection with tularemia come through contact with infected mammals. This contact can be in the form of bites or scratches from infected animals; it is also possible to pick up the pathogen through direct contact with feces or blood from infected animals. However, direct contact is not necessary to become infected with tularemia; the tularemia pathogen can also be ingested through the air or contaminated water.
Symptoms, complaints, and signs
Rabbit plague causes different symptoms in animals and humans. The eponymous rodents usually develop septicemia a few days after infection, which spreads over the entire body. Affected animals typically present with fever, increased respiratory rate, and enlarged lymph nodes and spleen. In addition, the animals appear severely weakened. In most cases, the rodents die of blood poisoning about two weeks after infection. Infected dogs do not usually die from rabbit plague, but they may develop distemper-like symptoms after infection. In humans, infection with the Francisella tularensis bacterium is usually accompanied promptly by symptoms similar to those of a flu-like infection. Patients initially suffer from fever and headache. These symptoms are often accompanied by nausea and vomiting. Many sufferers also experience swelling of the lymph nodes at the site where the bacterium entered the body. If the infection is not recognized and treated with antibiotics, a life-threatening condition can develop. This is often heralded by severe chills and abdominal pain. Many patients also experience severe pharyngitis. In humans, hare fever is not accompanied by symptoms specific to the disease, so it can only be detected beyond doubt by blood ananlysis.
Diagnosis and course
The diagnosis of tularemia is often inconclusive and sometimes even fails to be made at all, since the course of the disease sometimes resembles that of a flu-like infection. However, tularemia can be inferred from the common symptoms, such as ulceration of the skin and swelling of the lymph nodes. However, a direct diagnosis is only possible by means of animal testing. For this purpose, a blood sample is taken and injected into a test animal. If the pathogen is present, this can be detected by the antibody formation of the test animal, but it should be noted that due to the similarity of the tularemia to the thymus pathogen, a false diagnosis can be made. In humans, the incubation period is 1 – 10 days, after which time the typical symptoms appear.If tularemia is recognized early and treated appropriately with antibiotics, there are hardly any complications, but if the disease remains untreated, it leads to death in 30% of all cases. However, once the disease is overcome, there is lifelong immunity to the tularemia pathogen.
Complications
In the absence of treatment or inadequate treatment, tularemia can cause various ailments from which serious complications can arise. Typical of hare fever is the conspicuous swelling of the lymph nodes at the site of infection, which is occasionally associated with fever and a general feeling of illness. In a severe course, the fever rises to over 40 degrees Celsius, causing cardiovascular symptoms, dehydration, and other complications. Some patients also suffer from abdominal pain and migraine, both associated with severe malaise and a decrease in quality of life. The characteristic pharyngitis can spread, possibly causing inflammation of the sinuses or even pneumonia. Rabbit plague also favors the development of ulcers on the skin, which may also become inflamed or cause bleeding and scarring. Drug treatment using antibiotics such as doxycline or gentamycin is sometimes accompanied by side effects and interactions. Gastrointestinal complaints are particularly problematic, as these correlate with the symptoms of tularemia and can thus cause severe pain and fever. Long-term use of the corresponding preparations can cause sensitive damage to the internal organs, especially the liver, kidneys and heart.
When should you go to the doctor?
In the case of tularemia, the affected person is in any case dependent on a medical examination and treatment, since it can also not come to an independent cure. The earlier the disease is detected, the better is usually also the further course. In the worst case, tularemia can even lead to the death of the affected person, so a doctor should be contacted at the first symptoms and signs of the disease. A doctor should be consulted in the case of tularemia if the affected person suffers from an increased respiratory rate and if the patient’s spleen is significantly enlarged. Furthermore, the symptoms of common flu may also indicate this disease. Most patients suffer from severe pain in the abdomen and also inflammation in the throat or pharynx. If the symptoms of the flu do not disappear after a few days, a doctor should be consulted in any case. In the case of tularemia, either a general practitioner or directly a hospital can be visited.
Treatment and therapy
A treatment of tularemia is done with an antibiotic, this can be doxycline, ciprofloxacin or gentamycin, with the greatest success with streptomycin. Sulfonamides and penicillin should be avoided because of resistance on the part of the pathogen. The antibiotic of choice should be taken for 10 – 17 days to ensure relapse and complete cure of tularemia.
Prevention
A vaccine against tularemia already exists, but it is not available on the German market. However, prevention against tularemia is also possible by adhering to simple rules of conduct. When coming into contact with wild animals, disposable gloves should always be worn and contact with suspect animals should be avoided altogether. In addition, dust-proof respiratory masks should be worn when processing wild animals, which includes skinning and gutting. Veterinarians, forest workers, and hunters represent special risk groups in this regard.
Aftercare
In tularemia (rabbit plague), the extent of follow-up is determined by the type of pathogen and the severity of the disease process. Pathogens of tularemia can be essentially the “F. tularensis” subtype and the “holarctica” subtype. The subtype “F. tularensis” is common in North America. In 30 to 60 percent of all untreated cases of the disease, the pathogen leads to the death of the infected person. In the event of death, follow-up care focuses on coping with grief. For first-degree relatives, psychological counseling or care is recommended by physicians. The “holarctica” subtype occurs almost exclusively in Europe. The probability of dying from tularemia caused by the “holarctica” subtype tends to zero. The therapy of tularemia is recommended both for the subtype “F.tularensis” subtype and the “holarctica” subtype are always started clinically with medication (ciprofloxacin as monotherapy). After the clinical stay, the drug therapy is continued for about 14 days during the follow-up. In order to monitor the success of the therapy, blood analyses are also included in the follow-up. Often, in the case of the “holarctica” subtype, there is even spontaneous healing. With the subtype “F. tularensis”, on the other hand, a severe course of the disease is regularly to be expected. Secondary symptoms such as endocarditis, severe septicemia, pneumonia, and liver and kidney failure may occur. In addition to continuing drug therapy, the focus of follow-up care is then additionally on symptom care.
Here’s what you can do yourself
Tularemia is treated with antibiotics such as streptomycin or gentamicin. The medications must be taken strictly as prescribed by the physician. In addition, early initiation of therapy is important to avoid a severe course of the disease. Medical treatment can be supported by bed rest and an adapted diet. The weakened body needs sufficient fluids and nutrients, especially in the acute phase of the disease. Later on, a light diet should be eaten to avoid further stressing the irritated gastrointestinal tract. Because the condition can lead to conjunctival discomfort, driving a car is not allowed. Operating heavy machinery is also prohibited. For external inflammations or ulcers, care products from the pharmacy can help. In consultation with the doctor, ointments made from natural substances can be tried. Pregnant women diagnosed with hare fever must contact a specialized clinic. Since the use of strong antibiotics in pregnancy is not allowed, alternative methods of treatment must be chosen. So, in principle, in the case of hare fever, the rule is to take it easy and rest, in conjunction with following the doctor’s instructions. Those affected can exchange information with other sufferers on Internet forums or in a specialist center. Support from a partner or other caregiver is also important.