What is the Bartonella rochalimae pathogen?
Bartonella rochalimae belongs to the Bartonellaceae genus and is a gram-negative bacterial species. The pathogen was isolated from dogs in 2007 at the "University of California" in San Francisco/USA as well as at the Massachusetts General Hospital and the Centers for Disease Control and Prevention (CDC) in the United States. Its name comes from Brazilian researcher Henrique da Rocha Lima. The Bartonella rochalimae pathogen is closely related to B. henselae as well as B. quintana . The bacterium Bartonella henselae was identified as the cause of cat fever in the mid-1990s , while B. quintana caused trench fever in thousands of soldiers during the First World War. The Bartonella rochalimae pathogen has meanwhile been detected not only in the United States but also in South America and Europe.
What are the histological characteristics of the Bartonella rochalimae pathogen?
The Bartonella rochalimae pathogens are fastidious, pleomorphic and haemotropic bacteria. They can occur in mammals such as cats, dogs, red foxes, guinea pigs, coyotes, raccoons as well as rats. The main reservoir for Bartonella rochalimae pathogens are canids. This includes the entire family of domestic dogs. Fleas and, more rarely, ticks are assumed to be vectors for the Bartonella rochalimae pathogen. .
The Bartonella rochalimae pathogen is genetically related to B. clarridgeiae, which has the cat as its mammalian reservoir host. In addition to many animals such as the cat, humans can also become infected with the Bartonella rochalimae pathogen and fall ill from it. Deoxyribonucleic acid (DNA) sequencing of 478 genes could prove that B. rochalimae and B. clarridgeiae are grouped under clade 3. Both pathogens again differ from other Bartonella species. However, both have in common that they can often be detected in Bartonella infections of dogs.
What infections can the Bartonella rochalimae pathogen cause?
The Bartonella rochalimae pathogen can cause the following infections:
- Bacteraemia (presence of bacteria in the bloodstream),
- Fever,
- Splenomegaly (enlargement of the spleen),
- infective endocarditis (inflammation of the inner lining of the valves of the heart),
- chronic diseases
In
people, the bacterium can cause myalgia. This
refers to pain in the muscles. The
complaints listed above refer to a published study in which 18
dogs in the USA were examined in which the Bartonella
rochalimae pathogen could be diagnosed.
How common is infective endocarditis in dogs?
Infective endocarditis is relatively rare. However, a Bartonella pathogen can be the cause of infective endocarditis in dogs in over a third of all cases. So far, Bartonella diseases, also in animals, have been little researched. In this case, other antibiotics would have to be prescribed if it is suspected, or diagnosed that a Bartonella species is behind the disease .
How could the Bartonella rochalimae pathogen be detected?
The different genera of Bartonella are usually detected by polymerase chain reaction (PCR) assays. The exact species determination is then carried out by DNA sequencing. Scientists have now been able to develop a special PCR platform for Bartonella rochalimae pathogens, which targets the isolation of gltA and rpoB genes. The PCR platform can be used for the epidemiological evaluation of vectors as well as reservoirs and is also suitable for detecting B-rochalimae infection in humans .
In humans, the Bartonella rochalimae pathogen was isolated for the first time from the blood of a 43-year-old American woman who travelled to Peru for three weeks and was bitten by several insects. Initially, it was assumed that the patient's complaints were caused by Bartonella bacilliformis . This Bartonella species not only resembles B. rochalimae under the microscope, but is also transmitted in some regions of Peru by sand flies. 10 percent of those infected with B. bacilliformis develop the so-called Oroya fever.
What are the symptoms of Bartonella rochalimae infection in humans?
In the case of the 43-year-old American woman described above, the following symptoms occurred:
- a life-threatening anaemia (disease in which the number of red blood cells is low),
- an enlarged spleen,
- high fever,
- Insomnia
The symptoms were similar to those of typhoid fever and malaria.
How is Bartonella rochalimae infection treated in humans?
Since initially attributed the patient's illness to a Bartonella bacilliformis infection, she was treated with antibiotics based on this diagnosis. Her symptoms then quickly subsided . However, further investigations proved that it was a Bartonella rochalimae infection.
How is the Bartonella rochalimae pathogen transmitted?
Within of the studies, it could be shown that transmission of the Bartonella rochalimae pathogen is most prevalent in fleas, in 89.5 percent of all cases of disease. Especially in households in rural areas, a high prevalence of zoonotic Bartonella rochalimae was also detected. This suggests that guinea pigs also play a potential role as a reservoir of this bacterium.
Why is further research on Bartonella pathogens so important?
Particularly in immunocompromised people, Bartonella infections can cause certain clinical pictures. In order to assess its dangers, but also treatment options, it is important to further investigate the Bartonella genera. On the one hand, this can further advance the fight against these pathogens. On the other hand, a sound understanding of the host-pathogen interaction can provide conclusions about the basic functions of the human immune system. The research work should also take into account that a Bartonella pathogen can cause very different clinical pictures depending on the immune status of the patient.