Human Exposure to Novel Bartonella Species From Contact With Fruit Bats

Ying Bai; Modupe O.V. Osinubi; Lynn Osikowicz; Clifton McKee; Neil M. Vora; Maria Rosales Rizzo; Sergio Recuenco; Lora Davis; Mike Niezgoda; Ajoke M. Ehimiyein; Grace S.N. Kia; Akin Oyemakinde; Olufunmilayo Sanni Adeniyi; Yemi H. Gbadegesin; Olugbon A. Saliman; Abiodun Ogunniyi; Albert B. Ogunkoya; Michael Y. Kosoy; Idanre Bat Festival Investigation Team


Emerging Infectious Diseases. 2018;24(12):2317-2323. 

In This Article

Abstract and Introduction


Twice a year in southwestern Nigeria, during a traditional bat festival, community participants enter designated caves to capture bats, which are then consumed for food or traded. We investigated the presence of Bartonella species in Egyptian fruit bats (Rousettus aegyptiacus) and bat flies (Eucampsipoda africana) from these caves and assessed whether Bartonella infections had occurred in persons from the surrounding communities. Our results indicate that these bats and flies harbor Bartonella strains, which multilocus sequence typing indicated probably represent a novel Bartonella species, proposed as Bartonella rousetti. In serum from 8 of 204 persons, we detected antibodies to B. rousetti without cross-reactivity to other Bartonella species. This work suggests that bat-associated Bartonella strains might be capable of infecting humans.


Bats are natural reservoirs for a variety of pathogens.[1] However, despite the risk to human health, persons around the world still intentionally handle bats, often without taking appropriate precautions. This lack of precautions is particularly evident in the tropics, where bats are abundant and frequently roost within or in close proximity to humans and domestic animals. In Asia and Africa, larger fruit bats (family Pteropodidae) are used as food, for either cultural reasons or subsistence.[2] In some cultures, bat caves serve as spiritual sanctuaries.[3]

One particular situation that has attracted the attention of scientists is a bat festival that takes place biannually in the Idanre Hills area of Nigeria. During the festival, which has occurred for many years, men enter designated caves, often without appropriate personal protective equipment, to capture bats. Local customs forbid persons from entering the caves outside of these festivities without permission from the community leadership. The captured bats are then eaten, used in cultural rituals, or sold as bushmeat.[3] The predominant bat species within the caves is the Egyptian fruit bat (Rousettus aegyptiacus); colony sizes can reach >1,000.[4] Egyptian fruit bats are known reservoirs of zoonotic pathogens including Lagos bat virus, Marburg virus, and Yersinia pseudotuberculosis.[5–8] Given the close human-to-bat contact that occurs during the festival, there is a risk for spillover of batborne pathogens to humans.

The genus Bartonella currently includes >30 species of bacteria,[9] many of which have been described only recently. Various arthropod vectors seem to play an essential role in the maintenance and transmission of most known Bartonella species.[9,10] In recent years, recognition of multiple Bartonella species as human pathogens responsible for a wide range of clinical manifestations has grown. Numerous novel strains of Bartonella have been discovered in bats of various species around the globe, including the human pathogen Candidatus Bartonella mayotimonensis, which was originally detected in aortic valve tissue of a person with endocarditis.[11–13] In addition, a novel Bartonella genotype found in bats from the country of Georgia clustered with genotypes found in human forest workers from Poland.[14]

During 2010 and 2013, we researched the health risk to humans participating in the Idanre bat festival. We sampled bats and their ectoparasites from the caves and used them to identify a variety of zoonotic pathogens, including Bartonella. We recruited human participants from the surrounding community and surveyed them (through an orally administered questionnaire and serologic testing) to understand risk factors and the occurrence of pathogen spillover from bats to humans. We examined whether bats and ectoparasites of these bats within the caves used in the Idanre bat festival are infected with Bartonella, characterized any Bartonella species identified in bats or bat flies, and screened human serum samples for evidence of Bartonella infection.