What is Bartonellosis?

Bartonellosis????? Here are a few fascinating facts about the infective Bartonella bacteria.

A set of widely recognised infectious disorders known as Bartonellosis come on by bacteria from the Bartonella genus. At least 22 defined species of bacteria are included in this group, spreading by vectors like fleas, lice, and sandflies.
Bartonella infection prevention involves several steps aiming to stop the disease from progressing. You will gain extensive information on this infection's symptoms, diagnosis, course of treatment, and preventative measures through this article.

What is Bartonellosis?

A gram-negative intracellular facultative bacterium known as Bartonella is responsible for spreading zoonotic illnesses worldwide. More than 20 isolated species of Bartonella; Bartonella henselae, Bartonella quintana, and Bartonella bacilliformis, are related to human infections. These include peliosis hepatis, Oroya fever, Carrión's disease, and cat scratch disease. 

In Peru, Oroya fever first appeared in 1870 during the railway line construction from Lima to Oroya. The epidemic claimed the lives of a large number of construction workers. Some workers who survived the outbreak suffered from verruga peruana, which are nodular ulcerating skin lesions. Mountainous South American nations other than Peru, such as Columbia and Ecuador have also recorded outbreaks. Daniel Carrión, a medical student from Peru, died of Oroya fever in 1885 after injecting himself with material from the lesions. For this reason, Oroya fever is also known as Carrión’s disease.

Globally, there are 6.4 instances of cat-scratch disease per 100,000 adults and 9.4 cases per 100,000 children aged 5 to 9 years. The southeastern region of the United States has the highest incidence, with peaks in January, late summer, and fall. Since the early 20th century, trench fever outbreaks have been intermittent and epidemic in many nations globally, with the biggest epidemics occurring during World Wars 1 and 2. 

Homeless people are more likely to come into contact with the infection and are at a higher risk of developing trench fever. Bartonella bacilliformis diseases are sporadic in Chile, Guatemala, and Bolivia and endemic to Peru, Columbia, and Ecuador.1

Causes and transmission

This genus of bacteria has many species that can cause various forms of bartonellosis. The following are some typical causes and ways that bartonellosis can spread.

Cat-scratch diseaseBartonella henselaeThe cat flea (Ctenocephalides felis) bite is the source of the bacterium that causes cat scratch illness in cats. Scratches, bites, or infected saliva via torn skin can all spread the infection to humans.2
Trench feverBartonella quintanaThe three lice species, pediculus humanus corporis (body louse), pediculus humanus capitis (head louse), and pediculus humanus pubis (pubic louse) are the most prevalent vectors for trench fever. 
Faeces that contain the Bartonella quintana bacterium are more prone to transmit the disease. People who are homeless and those who live in crowded, unhealthy surroundings are more at risk.3
Carrion’s diseaseBartonella bacilliformisSand flies serve as the primary transmission mode. The most significant method is vector transmission. Other transmission methods include direct vaccination or contact with contaminated human blood.4

Signs and symptoms

Various diseases caused by bartonellosis have varied indications and symptoms.

Cat scratch disease

  • The site of a bite or scratch becomes the site of a primary inoculation lesion. Following exposure, a papule or pustule appears 5–10 days later. For a few weeks, this lesion can persist
  • Enlargement of lymph nodes
  • Fever
  • Malaise
  • Transverse myelitis: Inflammation and pain of the Spinal Cord
  • Radiculitis: Radiating pain from the spinal cord
  • Neuroretinitis: Inflammation of the optic nerve, presenting as vision loss, optic disc swelling and fluid deposits in the eye.
  • Encephalopathy: A change in cognitive function
  • Cerebellar ataxia: Inability to coordinate muscle movement
  • Parinaud Oculo-Glandular Syndrome: Seemingly pink-eye and swollen lymph glands in nearby areas

Bacillary angiomatosis and peliosis hepatis

  • Bacillary angiomatosis presents with skin lesions accompanied by lesions in lymph nodes, liver, spleen and bone marrow
  • Peliosis hepatis was first described in patients with tuberculosis and advanced cancer also found in HIV-infected individuals

Trench fever

Carrión’s disease

  • The acute phase (Oroya fever) is characterised by:
  • Chronic phase (verruga peruana) associated with recurring low-grade fever, blurred vision, photophobia, and eye irritation, accompanied by insomnia, restlessness, anaemia and poor balance 1,5


A series of clinical assessments, medical history, and laboratory tests serve to diagnose bartonellosis. Since several Bartonella species can produce a range of symptoms, the diagnosis methods can change.

Cat-scratch diseaseScalp, skin folds, and interdigital areas are inspected to find initial lesions with an examination of lymph nodesDetection of IgG and IgM antibodies in blood serum by Indirect Immunofluorescence Assays (IFA)Polymerase chain reaction (PCR) of lymph nodes and other tissues combined with DNA sequencingBiopsy of lymph node tissues 2,5,6Ultrasound is helpful in needle aspiration to extract tissues for biopsy
Trench feverEnlarged spleen that can be felt with palpation. Maculopapular (reddened flat and raised) rash on the trunk.Culture of bacteria in EDTA bottles or chocolate agar under 5% carbon dioxide for 21 days
Enzyme-linked immunosorbent test (ELISA) or an indirect fluorescence assay (IFA) to measure B. quintana antibodies including PCR and RT-PCR 3
Carrión’s diseaseObserving the physical symptoms and nodesMicroscopic examination of Giemsa-stained blood smear
Blood tests to find haemolytic anaemia, thrombocytopenia with elevated liver function tests
Abdominal imaging is used in cases of suspected hepatosplenic diseases 5,6 
Bacillary angiomatosis and peliosis hepatitisRaised, palpable skin lesions that range in colour from purple to red-black with swollen lymph nodes and liverHIV antibody testing and CD4+ lymphocyte assessment 5,6 

Treatment and management

The type of infection, its intensity, and the patient's general condition all play a role in dealing with and caring for bartonellosis. The following are standard methods for treating and controlling Bartonella infections.

Cat-scratch disease

Due to the self-limiting nature of the condition, patients who arrive with milder symptoms like lymphadenopathy and fever are typically not put on antibiotic therapy. Azithromycin, ciprofloxacin, gentamicin, trimethoprim-sulfamethoxazole, and rifampin are among the antimicrobial agents prescribed. Patients with severe lymphadenopathy should take oral azithromycin at doses of 500 mg on the first day and 250 mg on days 2 to 5. Oral doxycycline 100 mg twice daily for 4 to 6 weeks and oral rifampin 300 mg twice daily for 4 to 6 weeks are advisable for retinitis.

Trench fever or chronic bacteremia 

The disease is treated with oral Doxycycline at 200 mg once daily for four weeks and intravenous gentamicin at 3 mg/kg for two weeks.

Bacillary angiomatosis and peliosis hepatis 

Oral erythromycin 500 mg four times daily for three to four months.

Endocarditis with a confirmed Bartonella culture 

Oral Doxycycline 100 mg for six weeks and intravenous gentamicin at 3 mg/kg/day for 14 days.

Carrión’s Disease

Oroya fever (Acute phase)

Ciprofloxacin is the drug of choice, with chloramphenicol and ceftriaxone serving as highly effective alternatives.

Verruga peruana (Chronic phase)

The preferred substitutes to azithromycin include rifampin, ciprofloxacin, and chloramphenicol.1


Preventive measures are crucial, especially for those more vulnerable to Bartonella infections:

✅ Throughout the year, flea management should be initiated and continued.

Acaricides in the form of collars, spot-on, spray-on, and oral formulations should be applied regularly to protect cats and dogs from flea and tick infestations year-long

Routine cat claw trimming is encouraged, although no declawing is required

✅ Injuries caused by cats need medical treatment and cleaned up immediately with soap and water

Reduce your cat's exposure to fleas and other potential vectors by keeping them inside

 ✅  Adopt a healthy, flea-free cat that is at least one year old if a family member is immunocompromised and a new cat is needed

 Immunocompromised people should stay away from cats whose health condition is uncertain

❌ Avoid scratches and bites (this includes rough play with cats)

❌ Avoid bringing stray or shelter cats to the home without first disinfecting the area for fleas8,9


Is there a vaccine for Bartonellosis?

There is no vaccination available to protect against Bartonella infections.7

Is the disease bartonellosis serious?

Because Bartonella species can cause potentially serious complications (including endocarditis, persistent bacteremia, bacillary angiomatosis, and Carrion's disease), clinical suspicion, a prompt diagnosis, and early treatment can improve outcomes.10

When should I see the doctor?

It's crucial to visit a doctor if you have a fever, swollen lymph nodes, or any other symptoms and believe you might have been exposed to Bartonella bacterium through contact with animals or insects. Effective management requires a timely diagnosis and appropriate care.


Bartonella is responsible for acute, chronic, and vascular symptoms. The Bartonella species causing the infection and the patient's immune system contribute to the reported clinical manifestations. Although most cases are minor, some may have adverse effects. If you suspect an infection or experience symptoms, you should see a doctor to ensure a proper diagnosis and course of treatment.


This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Deepika Rana

Bachelor of Dental Surgery(BDS), Dentistry , H.P.Government Dental College, IGMC Shimla.Himachal Pradesh

Hi, I am Deepika Rana Dentist by profession finished my Clinical Research Certification Programme from Duke NUS Medical school, Singapore in 2022. I joined Klarity’s internship because of my ongoing desire to learn and educate others about medicine through Writing. I enjoy producing articles that give readers detailed information about a variety of ailments that can be accessed through the Health Library created by Klarity.

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