Drivers of Bartonella infection in micromammals and their fleas in a Mediterranean peri-urban area

Abstract

People living at the human/wildlife interface are at risk of becoming infected with Bartonella for which micromammals act as reservoir. We aimed to determine the factors related to the prevalence of Bartonella and its haplotype diversity in micromammals and in their fleas in a Mediterranean peri-urban environment. We analyzed 511 micromammals, chiefly 407 wood mice (Apodemus sylvaticus), captured into Barcelona metropolitan area (Spain) in spring and autumn from 2011 to 2013 in two natural and two adjacent residential areas, their fleas (grouped in 218 monospecific pools) and 29 fetuses from six Bartonella-positive female wood mice. Amplification of a fragment of ITS was carried out by real time PCR. Prevalence was 49% (57% in the dominant species, the wood mouse), and 12 haplotypes were detected. In general, prevalence was higher in those hosts more heavily infested by fleas, coincident with higher rates of capture, in autumn than in spring, and in adults than in juveniles. Prevalence did not differ between natural and residential areas except for one prevalent haplotype, which was more frequent in natural areas. Prevalence in flea pools (58%) was only explained by Bartonella occurrence in the pool host. In 56.4% of the flea pools with identified Bartonella haplotypes, we found the same haplotype in the host and in its flea pool. Prevalence in wood mouse fetuses was 69%, with at least one infected fetus in all litters, and two litters with all the fetuses infected. indicating that vertical transmission might be important in Bartonella epidemiology in the wood mouse. There is a hazard of Bartonella infection for people living in residential areas and those visiting peri-urban natural areas in Barcelona.

Risk factors of Leptospira infection in Mediterranean periurban micromammals

“…Higher Leptospira prevalence has been frequently associated with species occupying urban habitats (Andersen‐Ranberg et al., ), but this refers mostly to species such as Rattus spp., which are underrepresented in our wood mouse‐dominated sample (both in natural and residential areas). We also failed to detect differences between habitats in the ectoparasites infesting and Bartonella infecting these same micromammals (Cevidanes, Proboste, Chirife, & Millán, ; Cevidanes et al., ), suggesting that climatic conditions are relatively similar between residential and natural habitats. Mammal dispersal between natural and residential areas could also explain the lack of differences in Leptospira prevalence.…”

“…Low micromammal abundance was considered between 0.1 and 5 animals/traps/night; medium between 5 and 10; and high more than 10. One of these categories was assigned to each individual depending on the micromammal abundance of the sampling period and area in which it was captured (Cevidanes, Altet, Chirife, Proboste, & Millán, ). Due to the low number of juvenile micromammals, “age” was not included in the model, which was only fitted with observations corresponding to adult individuals.…”

Bartonella infections in three species of Microtus: prevalence and genetic diversity, vertical transmission and the effect of concurrent Babesia microti infection on its success

“…However, no bacteria were isolated from 58 viable pups born from infected mice in this study [28]. Recently, Bartonella DNA was detected in 69% of fetuses of Bartonella -infected wood mice ( Apodemus sylvaticus ) from the Barcelona region in Spain [29] and in one of 15 pups born to experimentally infected jirds [26]. In contrast to those studies, no congenital infections were recognized in bank voles Myodes glareolus in the UK [12].…”

“…In North America, 80% of litters and 47% of cotton rat ( S. hispidus ) embryos/newborns tested positive for Bartonella and 100% of litters and three out of three tested white-footed mouse ( P. leucopus ) embryos were found to be Bartonella -positive [27]. In the Barcelona region of Spain, 100% of litters and 69% of embryos of Bartonella -positive wood mice ( A. sylvaticus ) were positive [29]. A higher rate of transmission to offspring was recorded in an experimental study in BALB/c mice, with 76% of fetal resorptions positive for B. birtlesi [28] but a much lower success of vertical transmission was found in experimentally infected jirds: only one positive pup out of 15 born to infected dams [26].…”

Bartonella Bacteria in Urban Rats: A Movement From the Jungles of Southeast Asia to Metropoles Around the Globe

“…Microclimatic conditions in cities can affect development of the fleas found on rats (Krasnov et al, 2001) and, therefore, influence the transmission of some vector-borne bacteria. In addition, the urban environment affect availability of resources, specifically food, for rodents (Cevidanes et al, 2017), promoting higher concentration, and density of rats that in turn can facilitate density-dependent transmission of various zoonotic pathogens carried by these animals.…”