Prevalence and diversity of small rodent-associated Bartonella species in Shangdang Basin, China

Prevalence and genetic diversity of Bartonella spp. in wild small mammals from South Africa

Bartonella spp. are intracellular bacteria associated with several re-emerging human diseases. Small mammals play a significant role in the maintenance and spread of Bartonella spp. Despite the high small mammal biodiversity in South Africa, there is limited epidemiological information regarding Bartonella spp. in these mammals. The main aim of this study was to determine the prevalence and genetic diversity of Bartonella spp. from wild small mammals from 15 localities in 8 provinces of South Africa. Small mammals (n = 183) were trapped in the Eastern Cape, Free State, Gauteng, Limpopo, Mpumalanga, Northern Cape, North West, and Western Cape provinces of South Africa between 2010 and 2018. Heart, kidney, liver, lung, and spleen were harvested for Bartonella DNA screening, and prevalence was determined based on the PCR amplification of partial fragments of the 16S-23S rRNA intergenic spacer (ITS) region, gltA, and rpoB genes. Bartonella DNA was detected in Aethomys chrysophilus, Aethomys ineptus, Gerbillurus spp., Lemniscomys rosalia, Mastomys coucha, Micaelamys namaquensis, Rhabdomys pumilio, and Thallomys paedulcus. An overall prevalence of 16.9% (31/183, 95% CI: 12.2%-23%) was observed. Bartonella elizabethae, Bartonella grahamii, and Bartonella tribocorum were the zoonotic species identified, while the remaining sequences were aligned to uncultured Bartonella spp. with unknown zoonotic potential. Phylogenetic analyses confirmed five distinct Bartonella lineages (I-V), with lineage IV displaying strong M. coucha host specificity. Our results confirm that South African wild small mammals are natural reservoirs of a diverse assemblage of Bartonella spp., including some zoonotic species with high genetic diversity, although prevalence was relatively low.IMPORTANCESmall mammals play a significant role in the maintenance and spread of zoonotic pathogens such as Bartonella spp. Despite the high small mammal biodiversity in southern Africa including South Africa, there is limited epidemiological information regarding Bartonella spp. in these mammals across the country. Results from our study showed the liver and spleen had the highest positive cases for Bartonella spp. DNA among the tested organs. Bartonella elizabethae, B. grahamii, and B. tribocorum were the three zoonotic species identified and five distinct Bartonella lineages (I-V) were confirmed through phylogenetic analyses. To the best of our knowledge, this study presents the first extensive nuclear diversity investigation of Bartonella spp. in South African small mammals in South Africa.

Prevalence and molecular detection of Babesia microti in rodents in Southeastern Shanxi, China

Babesia is a tick-transmitted parasite that infects wild and domestic animals, causes babesiosis in humans, and is an increasing public health concern. Here, we investigated the prevalence and molecular characteristics of Babesia infections in the rodents in Southeastern Shanxi, China. Small rodents were captured, and the liver and spleen tissues were used for Babesia detection using traditional PCR and sequencing of the partial 18S rRNA gene. The analysis revealed that 27 of 252 small rodents were positive for Babesia, with an infection rate of 10.71%. The infection rates in different sexes and rodent tissues were not statistically different, but those in different rodent species, habitats, and sampling sites were statistically different. The highest risk of Babesia infection was observed in Niviventer confucianus captured from the forests in Huguan County. Forty-three sequences from 27 small rodents positive for Babesia infection were identified as Babesia microti, including 42 sequences from 26 N. confucianus, and one sequence from Apodemus agrarius. Phylogenetic analysis showed that all sequences were clustered together and had the closest genetic relationship with Babesia microti strains isolated from Rattus losea and N. confucianus in China, and belonged to the Kobe-type, which is pathogenic to humans. Compared to other Kobe-type strains based on the nearly complete 18S rRNA gene, the sequences obtained in this study showed the difference by 1-3 bp. Overall, a high prevalence of Babesia microti infection was observed in small rodents in Southeastern Shanxi, China, which could benefit us to take the implementation of relevant prevention and control measures in this area.

Molecular prevalence of vector borne bacterial pathogens in the blood samples of wild rodent species trapped from Saudi Arabia

Order Rodentia is the most speciose among mammals and the members of this order are known to host more than 60 zoonotic diseases and rodents are a potential health threat to humans. This study was designed to report the molecular prevalence and phylogenetic evaluation of various blood borne bacterial pathogens (Anaplasma ovis, Anaplasma phagocytophilum, Anaplasma marginale and Bartonella spp.) in the blood samples of four wild rodent species [Meriones rex (N = 27), Acomys dimidiatus (N = 18), Myomys yemeni (N = 6) and Rattus rattus (N = 3)] that were trapped during August till October 2020 from Al Makhwah governorate in Saudi Arabia. Results revealed by 9/54 (16.6%) rodents amplified Msp4 gene and 2/54 (3.7%) rodents amplified rpoB gene of Anaplasma ovis and Bartonella spp. respectively. Anaplasma phagocytophilum and Anaplasma marginale were not detected among enrolled rodent species. Meriones rex was the most highly infected rodent species. DNA sequencing and BLAST analysis confirmed the presence of Anaplasma ovis and the Bartonella koehlerae in rodent blood samples. Phylogenetic analysis of both pathogens showed that Saudi isolates were clustered together and were closely related to isolates that were reported from worldwide countries. Risk factor analysis revealed that prevalence of both bacterial pathogens was not restricted to a particular rodent species or a rodent sex (P > 0.05). In conclusion, we are reporting for the very first time that Saudi rodents are infected with Anaplasma ovis and rodents can be infected with Bartonella koehlerae. Similar studies at large scale are recommended in all those areas of Saudi Arabia that are unexplored for the incidence and prevalence of bacterial pathogens among the rodents that are living near human dwellings in order to prevent bacterial infections in local people as well as in livestock.

Zoonotic pathogens identified in rodents and shrews from four provinces, China, 2015-2022

Rodents and shrews are major reservoirs of various pathogens that are related to zoonotic infectious diseases. The purpose of this study was to investigate co-infections of zoonotic pathogens in rodents and shrews trapped in four provinces of China. We sampled different rodent and shrew communities within and around human settlements in four provinces of China and characterised several important zoonotic viral, bacterial, and parasitic pathogens by PCR methods and phylogenetic analysis. A total of 864 rodents and shrews belonging to 24 and 13 species from RODENTIA and EULIPOTYPHLA orders were captured, respectively. For viral pathogens, two species of hantavirus (Hantaan orthohantavirus and Caobang orthohantavirus) were identified in 3.47% of rodents and shrews. The overall prevalence of Bartonella spp., Anaplasmataceae, Babesia spp., Leptospira spp., Spotted fever group Rickettsiae, Borrelia spp., and Coxiella burnetii were 31.25%, 8.91%, 4.17%, 3.94%, 3.59%, 3.47%, and 0.58%, respectively. Furthermore, the highest co-infection status of three pathogens was observed among Bartonella spp., Leptospira spp., and Anaplasmataceae with a co-infection rate of 0.46%. Our results suggested that species distribution and co-infections of zoonotic pathogens were prevalent in rodents and shrews, highlighting the necessity of active surveillance for zoonotic pathogens in wild mammals in wider regions.

Genetic diversity of Bartonella infection in residential and field rodents in Hebei, China

Rodents are the primary natural reservoirs of Bartonella spp., and some of which are zoonotic causative agents. Hence, surveillance of Bartonella sp. infection in rodents is very important for the prevention of human bartonellosis caused by them. In this study, rodents were captured, and their spleen samples were collected for Bartonella sp. DNA detection and identification by amplifying the 16S rRNA, gltA, and ftsz genes using semi-nested polymerase chain reaction (PCR). The results indicated that Bartonella sp. DNA was detected in seven Rattus norvegicus individuals with a detection rate of 6.7% in Chengde City and bacterial DNA in 31 Apodemus agrarius individuals with a detection rate of 28.4% in Handan City. The DNA detection rate across the genders and ages of rodents was not found to be statistically significant. Furthermore, sequence analysis of the above-mentioned three genes demonstrated that at least eight Bartonella species were circulating in Hebei Province, of which three, including Bartonella rattimassiliensis, Bartonella grahamii, and Bartonella tribocorum, are human pathogens, thus suggesting the existence of a major public health risk. Overall, these results revealed the detection rate and genetic diversity of Bartonella species infection in rodents in Hebei Province, which could be potentially helpful for the prevention of bartonellosis caused by rodent-associated Bartonella species. This study highlights the urgent need for the surveillance of Bartonella infections in rodents and ectoparasites that affect both rodents and humans and can cause fever of unknown origin or endocarditis.

Host specificity and genetic diversity of Bartonella in rodents and shrews from Eastern China

Bartonella are vector-borne gram-negative facultative intracellular bacteria causing emerging infectious diseases worldwide, and two thirds of known Bartonella species are carried by rodents. We captured rodents, shrews and rodent ectoparasitic mites in rural areas of Qingdao City, Shandong Province, China from 2012 to 2021 and used the animal spleen tissues for the PCR amplification of Bartonella gltA and rpoB genes. PCR showed 9.4% (40/425) rodents, and 5.1% (12/235) shrews were positive for Bartonella. Seven Bartonella species including three novel species were identified in five rodent species and one shrew species, indicating the abundance and genetic diversity of Bartonella in rodents and shrews. The infection rate of each Bartonella species in the animal species was as below: novel Candidatus Bartonella crocidura in shrews Crocidura lasiura (5.1%, 12/235); novel Candidatus Bartonella cricetuli in hamsters Tscherskia triton (20%, 9/45); novel Candidatus Bartonella muris in striped field mice Apodemus agrarius (4.2%, 7/168) and house mice Mus musculus (1.5%, 2/135); Bartonella fuyuanensis in striped field mice (8.9%, 15/168) and house mice (0.7%, 1/135); Bartonella rattimassiliensis and Bartonella tribocorum in brown rats Rattus norvegicus (6.7%, 3/45 and 4.2%, 2/45, respectively); Bartonella queenslandensis in Chinese white-bellied rat Niviventer confucianus (12.5%, 1/8). These results suggest that Bartonella infected a variety of rodent and shrew species with high infection rate, but each Bartonella specie is restricted to infect only one or a few genetically closely related rodent species. In addition, Candidatus Bartonella cricetuli, Candidatus Bartonella muris and Bartonella coopersplainsensis were found in chigger Walchia micropelta (33.3%, 3/9), and B. fuyuanensis were found in chigger Leptotrombidium intermedium (4.1%, 1/24), indicating chiggers may be reservoirs of Bartonella. In conclusion, abundant genetic diversified Bartonella species are found to infect rodents, shrews and chiggers, but each Bartonella species has a strict rodent animal host specificity; and chigger mites may play a role in Bartonella transmission.