What is the Bartonella alsatica pathogen?

Bartonella alsatica is the name of a bacterium. The bacterium has been detected in the spleen and liver of wild rabbits and in the liver of domestic rabbits . If humans come into close contact with the infected animals, transmission of the Bartonella alsatica pathogen can occur. However, it is also possible that flea bites can cause an infection and eventually also an illness from the bacterium .

What are the medical characteristics of the Bartonella alsatica pathogen?

The Bartonella alsatica pathogen is a gram-negative alphaproteobacterium. Its natural host is the European rabbit (Oryctolagus cuniculus), in which it causes asymptomatic bacteraemia. The Bartonella alsatica pathogen is probably transmitted to humans by fleas (Spilopsyllus cuniculi as well as Xenopsylla cunicularis), although infection in humans is very rare . Since 2006, only four cases of Bartonella alsatica infectious diseases in humans have been detected and reported.

When was the Bartonella alsatica pathogen first discovered?

The Bartonella alsatica pathogen was first isolated in 1990 in the blood of wild rabbits in Alsace/France. Since then, Bartonella alsatica has been regarded as the pathogen that causes bacteraemia in wild rabbits. Although it is relatively rare, it is also possible for humans to become infected with the Bartonella alsatica pathogen. This can happen during a hunt, for example, where humans come into contact with wild rabbits. Of particular concern is when the wild rabbit is eviscerated by humans with their bare hands. However, transmission with the bacterium to humans is also possible through a flea or tick bite, for example .

What diseases can be transmitted by the Bartonella alsatica pathogen?

The bacterium Bartonella alsatica has been described as the causative agent of endocarditis and lymphadenitis in the already reported cases of illness. The clinical pictures can be presented as follows :

• Endocarditis: This is an infection of the inner lining of the heart, which primarily affects the heart valves. The Bartonella alsatica pathogens usually enter the bloodstream through small injuries in the mouth. Finally, the bacteria attach themselves to the inner skin of the heart, to the so-called endocardium. The endocardium is a thin, smooth layer of tissue that lines the inside of the heart and separates the heart muscle from the cavity of the heart.
• Lymphadenitis: This is an acute infection that affects one or more lymph nodes.

 
It is assumed that the Bartonella alsatica pathogen can be held responsible for febrile diseases in humans.

What are the symptoms of infections with the Bartonella alsatica pathogen?

• Endocarditis: An endocarditis is noticeable either by almost no symptoms at all to severe symptoms. These can include altered heart murmurs, but also severe fever, a general feeling of illness, pain in the limbs and/or chills, shortness of breath and bleeding in the skin. It is advisable to have the respective complaints clarified by a doctor and treated if necessary.
• Lymphadenitis:  Lymphadenitis is characterised by pain, tenderness of the affected lymph node and/or enlargement of the lymph node.

How is the Bartonella alsatica pathogen diagnosed?

In the past, Bartonella alsatica pathogens could be diagnosed in domestic rabbits by means of a DNA examination and/or PCR tests . In humans, the detection of Bartonella alsatica pathogens is more difficult, as the diagnosis can usually not be made by serology, culture or PCR. The respective diagnostic tests differ from each other as follows :

• Serology: The immunofluorescence test (IFT) and the enzyme-linked immunosorbent assay (ELISA) are distinguished from each other. The IFT has been the most widely used so far due to its commercial availability and comparatively simple handling .
• Culture: The cultivation of a culture for diagnostic detection usually requires a long incubation period of up to several weeks at . This is not possible at due to the long waiting period. This is often not practical due to the long waiting time for diagnosis . In addition, only a small number of Bartonella alsatica pathogens can usually be detected in human blood, which is why this method is rather unsuitable for diagnosis and is rarely carried out .
• PCR: As a rule, different genes can be used for PCR detection. According to a study by La Scola et al. from 2003, both RNA polymerase beta subunit and the citrate synthase gene can be used for PCR detection. In general, PCR detection offers a higher probability of detecting Bartonella alsatica pathogens in humans than culture.

How is a Bartonella alsatica infection treated?

An infection with the Bartonella alsatica pathogen in humans is rather rare. As a rule, however, the infection is treated with antibiotics . For example, the drug doxycycline can be used , which has a strong antipyretic effect and also counteracts the signs of inflammation. The drugs gentamicin and amoxicillin can also help in the therapy. Gentamicin is an aminoglycoside antibiotic that is commonly used as a sulphate salt in bacterial infections . The active ingredient amoxicillin can also help in the treatment of inflammation. The active substance amoxicillin, on the other hand, is a broad-spectrum antibiotic that belongs to the group of aminopenicillins . Amoxicillin belongs to the group of active substances known as ?-lactam antibiotics and has been used since 1981 for the treatment of infectious diseases. It can be used either in oral or parenteral form.

An infection with Bartonella alsatica usually leads to death in wild rabbits. They do not even necessarily have to show signs of disease, such as a bacteraemia. This is the presence of bacteria in the bloodstream.