Genetic diversity of vector-borne zoonotic pathogens in companion dogs and cats, Tianjin, China.

Background: Dogs and cats are the hosts of many vector-borne human pathogens that can be transmitted to humans. Given their direct and intimate contact with humans, companion dogs and cats are considered direct sentinels of vector-borne human pathogens. However, limited information is currently available regarding canine and feline zoonotic pathogens in China. This study detected canine and feline vector-borne human pathogens to better understand the potential risk to humans. Methods: Blood samples were collected from 275 domestic companion animals (117 dogs and 158 cats) living in Tianjin city, China, and the presence of DNA from Anaplasma, Babesia, Bartonella, and Rickettsia was detected by semi-nested polymerase chain reaction (PCR). The PCR products of the expected size were sequenced, and these newly generated sequences were subjected to BLASTN, nucleotide identity, and phylogenetic analyses. Results: A total of 24 blood samples tested positive for vector-borne pathogens in companion dogs and cats in Tianjin city, China, with a relatively low positive rate of 8.7%. Specifically, seven human pathogens, including Rickettsia raoultii, Candidatus Rickettsia jingxinensis, Rickettsia sibirica, Rickettsia felis, Babesia venatorum, Bartonella tribocorum, and Bartonella Henselae, were identified. In addition, Anaplasma ovis with zoonotic potential and Candidatus A. cinensis were detected. Conclusion: Our results indicate substantial genetic diversity in the vector-borne human pathogens circulating in companion dogs and cats. Interventions based on "One Health" should be taken to reduce the potential risks of contracting infection from companion dogs and cats in Tianjin, China.

Anaplasma, Bartonella, and Rickettsia infections in Daurian ground squirrels (Spermophilus dauricus), Hebei, China.

Rodents have been confirmed as hosts of various vector-borne zoonotic pathogens and are important for the maintenance of these microbes in nature. However, surveillance for zoonotic pathogens is limited for many wild rodent species in China, so our knowledge of pathogen ecology, genetic diversity, and the risk of cross-species transmission to humans is limited. In this study, 165 spleen samples of Daurian ground squirrels (Spermophilus dauricus) were collected from Weichang Manchu and the Mongolian Autonomous County of Hebei Province, China, and Rickettsia, Bartonella, and Anaplasma were identified by DNA detection using polymerase chain reaction (PCR). Sequence analysis identified eight bacterial pathogens: R. raoultii, R. sibirica, Candidatus R. longicornii, B. washoensis, B. grahamii, B. jaculi, A. capra, and Candidatus Anaplasma cinensis. Co-infection of B. grahamii and R. raoultii in one sample was observed. Our results demonstrated the genetic diversity of bacteria in Daurian ground squirrels and contributed to the distribution of these pathogens. Six species, A. capra, R. raoultii, R. sibirica, Candidatus R. longicornii, B. washoensis, and B. grahamii, are known to be pathogenic to humans, indicating a potential public health risk to the local human population, especially to herders who frequently have close contact with Daurian ground squirrels and are thus exposed to their ectoparasites.

Great genetic diversity of vector-borne bacteria and protozoan in wild rodents from Guangxi, China.

BACKGROUND: Rodents are recognized as the hosts of many vector-borne bacteria and protozoan parasites and play an important role in their transmission and maintenance. Intensive studies have focused on their infections in vectors, especially in ticks, however, vector-borne bacterial and protozoan infections in rodents are poorly understood although human cases presenting with fever may due to their infection have been found. METHODS: From May to October 2019, 192 wild rodents were trapped in wild environment of Guangxi Province, and the spleen samples were collected to reveal the presence of vector-borne bacterial and protozoan infections in them. The microorganisms in rodents were identified by detecting their DNA using (semi-)nested PCR. All the PCR products of the expected size were subjected to sequencing, and then analyzed by BLASTn. Furthermore, all the recovered sequences were subjected to nucleotide identity and phylogenetic analyses. RESULTS: As a result, 192 rodents representing seven species were captured, and Bandicota indica were the dominant species, followed by Rattus andamanensis. Based on the (semi-)nested PCR, our results suggested that Anaplasma bovis, Anaplasma capra, Anaplasma ovis, Anaplasma phagocytophilum, "Candidatus Neoehrlichia mikurensis", "Candidatus E. hainanensis", "Candidatus E. zunyiensis", three uncultured Ehrlichia spp., Bartonella coopersplainsensis, Bartonella tribocorum, Bartonella rattimassiliensis, Bartonella silvatica, two uncultured Bartonella spp., Babesia microti and diverse Hepatozoon were identified in six rodent species. More importantly, six species (including two Anaplasma, two Bartonella, "Ca. N. mikurensis" and Bab. microti) are zoonotic pathogens except Anaplasma bovis and Anaplasma ovis with zoonotic potential. Furthermore, dual infection was observed between different microorganisms, and the most common type of co-infection is between "Ca. N. mikurensis" and other microorganisms. Additionally, potential novel Bartonella species and Hepatozoon species demonstrated the presence of more diverse rodent-associated Bartonella and Hepatozoon. CONCLUSIONS: The results in this work indicated great genetic diversity of vector-borne infections in wild rodents, and highlighted the potential risk of human pathogens transmitted from rodents to humans through vectors.

Hemorrhagic fever caused by a novel tick-borne Bunyavirus in Huaiyangshan,China / 中华流行病学杂志

Background:From April to July in 2009 and 2010,unexplained severe hemorrhagic fever-like illnesses occurred in farmers from the Huaiyangshan mountains range.Methods:Clinical specimens (blood,urine,feces,and throat swabs) from suspected patients were obtained and stored.Mosquitoes and ticks in affected regions were collected.Virus was isolated from 2 patients and characterized by whole genome sequencing.Virus detection in additional patients and arthropods was done by virus-specific reverse transcription (RT) PCR.Clinical and epidemiological data of RT-PCR confirmed patients were analyzed.Results:An unknown virus was isolated from blood of two patients and from Haemaphysalis ticks collected from dogs.Whole genome sequence analysis identified the virus as a novel member of the family Bunyaviridae,most closely related to the viruses of the genus Phlebovirus within which it forms a separate lineage.Subsequently,infection was confirmed by RT-PCR in 33 of 58 suspected patients.The illness in these patients was characterized by fever,severe malaise,nausea,vomiting,and diarrhea.Prominent laboratory findings included low white cell- and platelet counts,coagulation disturbances,and elevation of liver enzymes.Hemorrhagic complications were observed in 3 cases,5 (15%) patients died.Conclusions:A novel tick-borne Bunyavirus causing life-threatening hemorrhagic fever in humans has emerged in the Huaiyangshan mountain areas of China.Further studies are needed to determine the epidemiology,geographic distribution and vertebrate animal ecology of this virus.