Seroprevalence of Orientia tsutsugamushi and Rickettsia typhi in water buffaloes (Bubalus bubalis) from Southern Thailand.

Background and Aim: Scrub typhus and murine typhus are globally distributed zoonoses caused by the intracellular Gram-negative bacteria Orientia tsutsugamushi and Rickettsia typhi, respectively. Numerous studies have been undertaken on rickettsial illnesses in humans and animals, including arthropod vectors, in Thailand. However, the reports on the seroprevalence of antibodies to O. tsutsugamushi and R. typhi in buffaloes is extremely rare. Thus, this study aimed to estimate the seroprevalence of both rickettsial infections in water buffaloes (Bubalus bubalis) in Phatthalung Province, southern Thailand. Materials and Methods: From February to March 2023, a total of 156 serum samples were collected from 156 water buffaloes on 29 farms in Phatthalung province. The sera were screened for antibodies against O. tsutsugamushi and R. typhi using an indirect immunofluorescence assay. Results: The seroprevalence of antibodies against O. tsutsugamushi and R. typhi in individual water buffaloes was 4.49% (95% confidence interval [CI]: 2.19%-8.97%) and 3.85% (95% CI: 1.77%-8.14%), respectively, whereas 31% (9/29) of the herds had buffaloes with antibodies. The number of buffaloes with scrub typhus infection and ectoparasite infestation was statistically significant (p < 0.05; odds ratio = 6.25 [95% CI: 1.19-33.33]). Intriguingly, the prevalence of scrub typhus antibodies in buffaloes that were not infested with ectoparasites was much higher than those that were. Conclusion: This is the first report of O. tsutsugamushi and R. typhi antibodies in water buffalo sera in Southern Thailand. Two serum samples showed a high antibody titer against O. tsutsugamushi. Seroprevalence mainly occurred in non-ectoparasite-infested buffaloes, especially for O. tsutsugamushi antibodies. At the herd level, one-third of the studied farms showed seroprevalence. Additional research on the occurrence of these pathogens in vectors and in other animal reservoirs is necessary.

First report of three novel Bartonella species isolated in rodents and shrews from nine provinces of Thailand.

Background and Aim: Bartonella spp. are Gram-negative zoonotic bacteria that are transmitted to humans by several types of animal hosts, including rodents. Several studies have been conducted on the prevalence of Bartonella infections in rodents. However, the risk of rodent-associated Bartonella spp. infection in humans remains unclear. This study aimed to estimate the prevalence and genetic heterogeneity of Bartonella spp. in rodents and shrews from nine provinces of Thailand using culture and molecular techniques. Materials and Methods: A total of 860 blood samples from rodents and shrews across nine provinces of Thailand were collected from January 2013 to June 2016. Bartonella spp. were isolated from all samples using conventional culture techniques and polymerase chain reaction. Phylogenetic tree analysis was used to align the Bartonella sequences obtained from this study. Results: The prevalence of Bartonella spp. in rodents and shrews was 11.5% (99/860, 95% confidence interval: 9.38-13.64%). The following nine species of Bartonella were detected: Bartonella tribocorum, Bartonella rattimassiliensis, Bartonella queenslandensis, Bartonella elizabethae, Bartonella chanthaburi spp. nov., Bartonella satun spp. nov., Bartonella coopersplainsensis, Bartonella ranong spp. nov., and Bartonella henselae. The prevalence of Bartonella-positive animals differed significantly among provinces. Conclusion: To the best of our knowledge, the three novel Bartonella spp. isolated from rodents and shrews across Thailand were detected for the first time in this study. Further studies on the epidemiology of Bartonella infection in rodents and its interaction with human health should be conducted in accordance with the Thai government's "One Health" approach to humans, animals, and the environment.

Detection of antibodies against three zoonotic Bartonella spp. and cross-reactivity among species and Coxiella burnetii in dogs and cats from Central Thailand.

Dogs and cats are important reservoir hosts of bacterial zoonotic pathogens, especially the Proteobacteria, Bartonella spp., and Coxiella burnetii. Bartonella spp. and C. burnetii are Gram-negative intracellular bacteria causing cat-scratch disease and query fever, respectively. Despite these two pathogens being dangerous, studies of their seroprevalence and cross-reactivity are limited in Thailand. The objectives of this study were to detect the seroprevalence of three zoonotic species of Bartonella and to evaluate cross-reactivity among Bartonella spp. and with C. burnetii. In total, 570 dog and cat serum samples were detected for antibodies against Bartonella spp. and C. burnetii using an indirect immunofluorescence antibody (IFA) test. At titer ≥ 1:64, tested serum that had a fluorescent intensity score ≥ 2 was interpreted as positive. Additionally, possible factors related to the seroprevalence were analyzed consisting of sex, breed, age, residing area, and ectoparasite control. Overall, the seroprevalence levels of Bartonella spp. and C. burnetii were 13.16% and 1.23%, respectively. All antigens of Bartonella were reacted to sera (1.23-7.72%), furthermore, both phases of C. burnetii were revealed in sera (0.35-1.05%). Interestingly, there was a poor agreement of cross-reactivity among Bartonella spp. at 5.56-8.70%, while cross-reactivity between Bartonella spp. and C. burnetii also showed poor agreement (2.80%). It is suggested that dogs and cats are important reservoirs of Bartonella spp., even in animals with ectoparasite control. The Bartonella seroprevalence was high in pure-breed animals with ectoparasite control, reflecting that Bartonella spp. infections can occur in owned, well-cared-for, and asymptomatic dogs and cats.

Isolation and phylogenetic analysis of Bartonella species from Rusa deer (Rusa timorensis) in Thailand.

The aim of the present study is to investigate the prevalence of Bartonella infection in deer in Thailand and to characterize the isolates by biochemical, morphological and genetic analysis. A total of 247 blood samples were collected from Rusa deer (Rusa timorensis) in a livestock breeding facility in Thailand. Bartonella bacteria were isolated in 3.6% of the blood samples. Three out of 110 (2.7%) males and 6 of 137 (4.4%) females were positive for Bartonella. A higher prevalence of Bartonella was observed in young deer under 4 years of age compared to adults over 4 years of age, but no Bartonella was isolated from deer over 8 years of age. Phylogenetic analysis of concatenated sequences of seven loci of Bartonella indicated that all the isolates from Rusa deer in Thailand were identical and formed a distinct cluster from other known Bartonella species.

Seroprevalence of Coxiella burnetii Antibodies Among Ruminants and Occupationally Exposed People in Thailand, 2012-2013.

AbstractLittle is known about the burden of Q fever in Thailand. We conducted a serological study to describe the prevalence of anti-Coxiella burnetii antibodies among ruminants and occupationally exposed persons in response to the report of the first two Q fever endocarditis patients in Thailand in 2012. We randomly selected ruminant sera from brucellosis surveillance and examined sera of 661 occupationally exposed subjects from two provinces of Thailand: Chiangmai and Nakornratchasima. Animal and human sera were tested using commercial enzyme-linked immunosorbent assay (ELISA). Environmental samples, vaginal swab, and milk from cows in Chiangmai farms with detectable anti-C. burnetii serum antibodies were tested using polymerase chain reaction (PCR). Among the 1,632 animal sera tested, 64 (3.9%) were seropositive. The prevalence was highest in dairy cattle (4.6%, 45/988), followed by goats (3.5%, 18/516) and sheep (2.1%, 1/48). The prevalence of anti-C. burnetii antibodies in each species varied significantly by province: the prevalence in cattle was higher in Chiangmai (5.5% versus 0%), however, the prevalence in sheep and goats was higher in Nakornratchasima (5.9% versus 1.0%). Four out of 60 milk samples were positive by PCR (6.7%). No environmental samples were positive. Among 661 human samples, 83 (12.6%) were ELISA positive. Seroprevalence was statistically higher in Chiangmai compare with Nakornratchasima (42.8% versus 3.0%). Coxiella burnetii infection exists in Thailand, but the prevalence varies by geographic distribution and animal reservoirs. Further studies focusing on the burden and risk factors of C. burnetii infection among high-risk groups should be conducted.

PREVALENCE AND DIVERSITY OF BARTONELLA SPECIES IN WILD SMALL MAMMALS IN ASIA.

We collected 641 small mammals belonging to 17 species of Rodentia and four species of Soricomorpha in Japan, Korea, Russia, Taiwan, and Thailand and investigated the prevalence and genetic diversity of Bartonella species. Apodemus (field mice) and Rattus (rats) were the most-common genera captured, making up 56.0% and 23.1% of the total specimens, respectively. Bartonellae were isolated from 54.6% of the collected animals, and the prevalence varied depending on the host species and the country of origin. The isolates were identified to the species level based on gltA and rpoB sequences. Although most Bartonella species were shared by more than two host species, the distribution patterns of Bartonella species clearly differed among the four most-common host genera: Apodemus, Rattus, Myodes (voles), and Suncus (shrews). The predominant Bartonella species were Bartonella grahamii in Apodemus, Bartonella tribocorum in Rattus, B. grahamii and Bartonella taylorii in Myodes, and an unclassified Bartonella sp. in Suncus.

Prevalence of zoonotic Bartonella species among rodents and shrews in Thailand.

We investigated the prevalence of Bartonella species in 10 rodent and one shrew species in Thailand. From February 2008 to May 2010, a total of 375 small animals were captured in 9 provinces in Thailand. Bartonella strains were isolated from 57 rodents (54 from Rattus species and 3 from Bandicota indica) and one shrew (Suncus murinus) in 7 of the 9 provinces, and identified to the species level. Sequence analysis of the citrate synthase and RNA polymerase ß subunit genes identified the 58 isolates from each Bartonella-positive animal as B. tribocorum in 27 (46.6%) animals, B. rattimassiliensis in 17 (29.3%) animals, B. elizabethae in 10 (17.2%) animals and B. queenslandensis in 4 (6.9%) animals. R. norvegicus, R. rattus, and Suncus murinus carried B. elizabethae, which causes endocarditis in humans. The prevalence of Bartonella bacteremic animals by province was 42.9% of the animals collected in Phang Nga, 26.8% in Chiang Rai, 20.4% in Sa Kaeo, 16.7% in Nakhon Si Thammarat, 12.0% in Surat Thani, 9.1% in Mae Hong Son and Loei Provinces. These results indicate that Bartonella organisms are widely distributed in small mammals in Thailand and some animal species may serve as important reservoirs of zoonotic Bartonella species in the country.