Bartonella bacilliformis

Bartonella bacilliformis is a gram-negative bacterium that is the etiologic agent of Carrion's disease, a disease endemic to the Andean regions of South America. This bacterium is a member of the genus Bartonella, which includes several species associated with various human and animal diseases. Bartonella bacilliformis is primarily transmitted to humans through the bite of infected sandflies, particularly species of the genus Lutzomyia.

Epidemiology

Bartonella bacilliformis is found exclusively in certain areas of South America, especially in Peru, Ecuador, and Colombia. The transmission of this bacterium is closely associated with the ecological distribution of its vector, the Lutzomyia sandfly, which thrives in Andean mountain valleys at elevations of 500 to 3200 meters. The incidence of Carrion's disease peaks during and after the rainy season, correlating with the breeding cycle of the sandfly.

Clinical Manifestations

Carrion's disease presents in two distinct phases: the acute phase, known as Oroya fever, and the chronic phase, known as Verruga Peruana or Peruvian wart.

Oroya Fever

The acute phase, Oroya fever, is characterized by high fever, hemolytic anemia, and immunosuppression. Without treatment, the mortality rate can be as high as 40%. The onset of symptoms typically occurs 3 to 12 weeks after the initial sandfly bite.

Verruga Peruana

The chronic phase, Verruga Peruana, can occur weeks to months after the acute phase. It is marked by the appearance of angiogenic skin lesions that can range from small, benign nodules to large, eruptive, and sometimes painful masses.

Diagnosis

Diagnosis of Bartonella bacilliformis infection is primarily based on clinical symptoms and confirmed through laboratory tests. These tests include blood cultures, serology, and molecular techniques such as PCR to detect bacterial DNA.

Treatment

The treatment of choice for Carrion's disease is antibiotics. The acute phase is typically treated with chloramphenicol, ciprofloxacin, or azithromycin. The chronic phase requires the administration of rifampin or macrolides to eliminate the skin lesions.

Prevention

Preventive measures focus on reducing exposure to the sandfly vector. This includes the use of insect repellent, protective clothing, and bed nets, especially in endemic areas. There is currently no vaccine available for Carrion's disease.

Research

Research on Bartonella bacilliformis and Carrion's disease is ongoing, with efforts focused on understanding the bacterium's pathogenesis, improving diagnostic methods, and developing effective vaccines.