Oroya fever, a severe infectious disease caused by the bacterium Bartonella bacilliformis, remains classified as a neglected tropical disease due to its limited occurrence in high-altitude valleys of the South American Andes. The illness is primarily found in Peru, with cases also reported in Ecuador and Colombia. Transmission occurs through bites from infected Lutzomyia sandflies.
The disease presents with high fever and significant destruction of red blood cells, leading to severe hemolytic anemia. Without antibiotic intervention, Oroya fever can be fatal in up to 90 percent of cases. Complicating treatment efforts, approximately 26 percent of Bartonella bacilliformis strains are now resistant to ciprofloxacin, the standard antibiotic used for this infection.
Researchers warn that climate change and increased travel could allow Lutzomyia sandflies to expand their range beyond South America and potentially reach other continents, including Europe.
An international team led by Professor Volkhard Kempf from Universitaetsmedizin Frankfurt and Goethe University has analyzed over 1,700 genetic variants of Bartonella bacilliformis. The study identified two proteins essential for the bacterium’s ability to destroy red blood cells: a porin protein facilitating substance exchange with the environment and an enzyme called α/β-hydrolase. According to Dr. Alexander Dichter, first author of the study, "Both proteins work together to destroy human erythrocytes and thereby provide an explanation for the characteristic clinical presentation of Oroya fever." Dichter added that "This makes the α/β-hydrolase a suitable target protein for therapeutic agents."
Laboratory experiments revealed that a phospholipase inhibitor can block α/β-hydrolase activity and prevent red blood cell destruction. Dichter stated, "If we succeed in selectively disabling the disease-causing effect of the bacterium in the human body in this way, we may have a therapy against which resistance is unlikely to develop."
Professor Kempf highlighted the public health impact: "Oroya fever is a serious public health problem in Peru and South America, killing hundreds of people every year without drawing attention from the rest of the world. The disease is poverty-related and belongs to the neglected tropical diseases, which receive far too little attention." He continued: "We are therefore all the more pleased that we have laid the foundation for developing novel therapeutic approaches for Oroya fever and thus made an important contribution to the fight against this deadly neglected tropical disease."
With initial funding concluded, researchers are seeking additional support to continue their work. Kempf noted future research aims include understanding how Bartonella bacilliformis binds to red blood cells—a critical step in infection—building on previous findings related to another pathogen.
