Scientists Discover Mysterious Disease-Causing Bacteria In Brazil

Researchers in Brazil have discovered a new species of bacteria belonging to the genus Bartonella in phlebotomine insects, commonly known as sand flies, in the Amazon National Park in the state of Para. While sand flies are usually linked to transmitting leishmaniasis, the DNA of this new bacterium shows similarities to Bartonella bacilliformis and Bartonella ancashensis, both responsible for Carrion's disease-also called Peruvian wart or Oroya fever-in Andean countries.

Currently, there is no evidence that the newly discovered species causes disease in Brazil. However, experts stress that further studies are crucial, as Bartonella bacteria are known to trigger several illnesses elsewhere.

Leading the Research

The study was conducted by Marcos Rogerio Andre, in partnership with Eunice Aparecida Bianchi Galati, affiliated with Sao Paulo State University and the University of Sao Paulo's School of Public Health. It was supported by FAPESP through two projects and published in the journal Acta Tropica. Additional contributors included Paulo Vitor Cadina Arantes, Israel de Souza Pinto, Daniel Antonio Braga Lee, Anna Claudia Baumel Mongruel, and Rosangela Zacarias Machado.

Understanding Bartonellosis

Bartonellosis refers to a group of diseases caused by Bartonella bacteria, which can be transmitted through sand flies, fleas, and lice. Infections are often slow to resolve and can remain undetected in the body, posing a higher risk to individuals with weakened immune systems.

"Bartonellosis is a neglected disease. The disease best known to health professionals is cat scratch disease, caused by Bartonella henselae. It's important to understand the real prevalence of these diseases, especially in isolated regions with low human development indices, where populations don't have easy access to health services," explains Andre.

Field Research in the Amazon

The study focused on 297 female sand flies collected between February 2022 and February 2023 along trails near the Urua and Tracoa rivers inside the Amazon National Park.

“This park has caves and receives many visitors, so it's important to study it,” said Andre.

Galati adds, "The discovery of Bartonella species in phlebotomine sand flies here in Brazil may indicate that B. bacilliformis and B. ancashensis, which cause Carrion's disease or Peruvian wart, can adapt to non-Andean species and be transmitted in areas outside the Andes. This isn't too much of an extrapolation, as two species that have been identified as vectors of B. bacilliformis, Pintomyia robusta and Pintomyia maranonensis in Peru, are very similar to species found in Brazil, namely Pintomyia serrana and Pintomyia nevesi."

Expanding the Research

This discovery is part of a broader effort by André and his team to study the diversity of Bartonella bacteria in humans and animals. According to the researchers, the sequences found in the Amazon differ from those in Peru but align with previous findings in Acre, another Brazilian state in the Amazon.

"We're detecting a strain here in Brazil that's never been described and is very similar to two species of the Bartonella genus that cause disease in Andean countries. Despite this similarity, we don't yet have information on whether it can cause disease with distinct symptoms. That's why we need to study them further," said Andre.

Next Steps

The research team plans to continue mapping insects and the bacteria they may carry across different Brazilian biomes. "The next steps are to continue investigations involving more populations of phlebotomine sand flies and other diptera from different biomes in search of these strains, as well as to look for other strains," explained Galati.

They also aim to identify the animals these insects feed on to determine possible reservoirs. "I have a project funded by FAPESP in which I was able to store many specimens of phlebotomine sand flies from the Atlantic Forest of Sao Paulo, and the idea is to explore this material in partnership with Professor Andre," Galati said.

A Call for Vigilance

Although results are preliminary, the study highlights the importance of monitoring previously undetected pathogens. Andre emphasized the need for collaboration between doctors and researchers: "Could people with fever who are often sent home and who have repeated episodes of fever be infected with this pathogen? Could patients with Leishmania also be co-infected with this new species of Bartonella?"

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