Bartonella spp. in Bats, Kenya | CDC EID

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Volume 16, Number 12–December 2010
Research
Bartonella spp. in Bats, Kenya

Michael Kosoy, Comments to Author Ying Bai, Tarah Lynch, Ivan V. Kuzmin, Michael Niezgoda, Richard Franka, Bernard Agwanda, Robert F. Breiman, and Charles E. Rupprecht
Author affiliations: Centers for Disease Control and Prevention, Fort Collins, Colorado, USA (M. Kosoy, Y. Bai, T. Lynch); Centers for Disease Control and Prevention, Atlanta, Georgia, USA (I.V. Kuzmin, M. Niezgoda, R. Franka, C.E. Rupprecht); National Museum of Kenya, Nairobi, Kenya (B. Agwanda); and Centers for Disease Control and Prevention in Kenya, Nairobi (R.F. Breiman)

Suggested citation for this article

Abstract
We report the presence and diversity of Bartonella spp. in bats of 13 insectivorous and frugivorous species collected from various locations across Kenya. Bartonella isolates were obtained from 23 Eidolon helvum, 22 Rousettus aegyptiacus, 4 Coleura afra, 7 Triaenops persicus, 1 Hipposideros commersoni, and 49 Miniopterus spp. bats. Sequence analysis of the citrate synthase gene from the obtained isolates showed a wide assortment of Bartonella strains. Phylogenetically, isolates clustered in specific host bat species. All isolates from R. aegyptiacus, C. afra, and T. persicus bats clustered in separate monophyletic groups. In contrast, E. helvum and Miniopterus spp. bats harbored strains that clustered in several groups. Further investigation is needed to determine whether these agents are responsible for human illnesses in the region.

An unprecedented, increasing interest in bats as reservoirs of infectious diseases occurred during the past decade. Mounting evidence indicates an association of bats with various emerging infections, some with high mortality rates, including lyssaviruses, severe acute respiratory syndrome and other coronaviruses, and henipa, Ebola, and Marburg viruses (1–6). However, the list of pathogens discovered in bats is even more extensive and includes other representatives from various taxonomic groups (6–8). Most infectious agents in bats are viruses; bacterial species have been rarely reported (9). Excluding reports resulting from serologic and microscopic observations before the 1990s, only a few recent publications describe bacterial species in bats. One publication reports fatal borreliosis in a bat caused by a relapsing fever spirochete in the United Kingdom (10). Another study on the molecular detection of hemoparasites infecting bats in southwest England showed the presence of Bartonella spp. DNA in the blood of 5 of 60 tested bats (11). This report on bat infection potentially caused by bacteria of the genus Bartonella is consistent with studies showing detection of Bartonella spp.–specific DNA in ectoparasites collected from bats in Egypt and the United States (12–14).

Bartonella spp. are mainly hemotropic, facultative intracellular parasites associated with erythrocytes and endothelial cells of mammals (15,16). Bartonella spp. organisms are highly adapted to a wide variety of mammals, including rodents, insectivores, carnivores, ungulates, and marine mammals such as dolphins. New insights into the natural history of various Bartonella spp. suggest that these bacteria have adapted to their mammalian reservoir hosts in unique ways with frequently restricted host species ranges (17). The bacteria can cause chronic intraerythrocyte infections that sometimes result in a large proportion of the reservoir host population being bacteremic simultaneously (18). Infections usually cause few or no clinical signs in the reservoir hosts. Host adaptation is evident as some Bartonella species and genotypes are found in very specific mammalian species.

Available data on Bartonella spp. have expanded rapidly during recent years, as this group of organisms has been found to be associated with a growing spectrum of emerging and reemerging diseases. In addition to cat-scratch disease, trench fever, and Carrión disease, other illnesses linked to Bartonella spp. infection range from a self-limiting, short-term fever to potentially fatal systemic diseases with cardiovascular, nervous system, or hepatosplenic involvement (19). Some Bartonella spp. that have been implicated as human pathogens are linked to rodent species; these species include B. elizabethae, B. grahamii, B. washoensis, and B. vinsonii subsp. arupensis (20–23). Other Bartonella spp. are linked to wild and pet carnivores. For example, B. henselae, carried by cats, causes cat-scratch disease in immunocompetent persons and bacillary angiomatosis in immunocompromised persons (19,24); B. vinsonii subsp. berkhoffii has been carried by dogs and is responsible for endocarditis in a human patient (24,25). For some Bartonella spp. recently implicated as human pathogens (such as B. rochalimae, which was isolated from an American tourist traveling to Peru, or B. tamiae, isolated from 3 patients in Thailand), a mammalian reservoir has not been determined despite a wide range of tested animals collected in these countries (26,27). These unidentified reservoirs indicate a need for extensive surveillance among diverse groups of animals for Bartonella strains, especially among bats, which represent around 20% of all mammalian species (6).

This study was conducted within the framework of the Centers for Disease Control and Prevention (CDC) Global Disease Detection program, which is designed to estimate the health and financial effects and transmission patterns of emerging infectious pathogens associated with humans and animals (including bats, rodents, and other likely reservoirs for human infection) in Kenya and other locations. This study had 5 objectives: 1) to estimate prevalence of Bartonella spp. infections among diverse chiropteran species in Kenya; 2) to isolate and identify detected Bartonella spp. and create a reference collection of Bartonella isolates from East Africa with further characterization and diagnostic investigation; 3) to evaluate genetic heterogeneity of circulating Bartonella strains by using the partial sequence variability of the citrate synthase gene (gltA), proven to be an excellent genetic marker for analysis of Bartonella strains (28); 4) to compare Bartonella strains obtained from bats in this study with strains obtained from other animal reservoirs and available from the public domain; and 5) potentially to identify new species of Bartonella.

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Bartonella spp. in Bats, Kenya | CDC EID


Suggested Citation for this Article

Kosoy M, Bai Y, Lynch T, Kuzmin IV, Niezgoda M, Franka R, et al. Bartonella spp. in bats, Kenya. Emerg Infect Dis [serial on the Internet]. 2010 Dec [date cited]. Available from http://www.cdc.gov/EID/content/16/12/1875.htm

DOI: 10.3201/eid1612.100601

Comments to the Authors

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Michael Kosoy, Centers for Disease Control and Prevention, 3150 Rampart Rd, Fort Collins, CO 80521, USA; email: mck3@cdc.gov