Sonthaya Tiawsirisup

Background: Dairy cattle are important livestock in Thailand and may be affected by infectious agents, including hemotropic Mycoplasma spp. (hemoplasmas), which may cause economic losses and reduced productivity. Two common bovine hemoplasma species, Mycoplasma wenyonii ( Mw ) and “ Candidatus Mycoplasma haematobovis” corrig. (formerly “ Candidatus Mycoplasma haemobos”; C Mhb), have been reported worldwide. However, although several putative species have been hypothesized to circulate in cattle or buffaloes, comprehensive genetic analyses of Mw and C Mhb from Thailand remain limited. Methods: In this study, we investigated the molecular occurrence and genetic diversity of bovine hemoplasmas in 522 dairy cattle from Thailand using 16S and 23S rRNA genes. A total of 522 blood samples were screened for hemoplasma infection using a PCR targeting the 16S rRNA gene. A non-random subset of 52 of the 161 PCR-positive samples, selected primarily on the basis of strong and discrete PCR bands, was successfully sequenced for both the 16S and 23S rRNA genes. Results: PCR detected hemoplasmas in 30.8% (161/522; 95% CI 26.9%–35.0%) of cattle. Of 161 positive samples, 52 were successfully sequenced for both 16S and 23S rRNA genes. Among the 52 non-randomly selected samples, phylogenetic analyses identified sequences assigned to two recognized bovine hemoplasma taxa and two additional divergent lineages within the Mw complex. These lineages are provisionally regarded as candidate lineages pending genomic and biological characterization. Conclusions: This study demonstrates underrecognized genetic diversity within the Mw complex in Thai dairy cattle. The divergent lineages were identified based on analyses of partial 16S and 23S rRNA gene sequences. Confirmation of their taxonomic status will require whole-genome sequencing, additional independent genetic markers, and biological characterization, including investigation of their pathogenicity and transmission.

Introduction: Rickettsioses are predominantly zoonotic infections that circulate among animal populations and can be transmitted to humans, representing emerging vector‐borne diseases spread through infected arthropod vectors. Rickettsia asembonensis displays a broad geographic distribution and is predominantly associated with fleas. Recent reports have identified R . asembonensis in febrile human patients in Malaysia, Peru, and Zambia, underscoring its emerging zoonotic potential. In Thailand, however, investigations of Rickettsia spp. have concentrated mainly on ticks and fleas, with comparatively little information regarding infections in pet dogs and cats. Methods: The present study examined Rickettsia spp. in 968 pets, 472 client‐owned dogs, and 496 client‐owned cats from the Bangkok and Nakhon Pathom regions, using the 17‐kDa gene as a molecular marker. Genetic analyses of Rickettsia species were performed using maximum‐likelihood phylogeny with IQ‐TREE, Bayesian inference, pairwise sequence similarity assessment, and nucleotide sequence type network analysis. Results: A total of 114 pets tested positive, corresponding to a prevalence of 11.8%, with 21.6% (102/472) in dogs and 2.4% (12/496) in cats. Of these, 48 samples were sequenced, leading to the identification of R . asembonensis and either uncultured Rickettsia spp. or the Rickettsia endosymbiont of Haemaphysalis bispinosa . Statistical analysis indicated significantly higher infection rates in pet dogs and cats from the Nakhon Pathom region. Phylogenetic reconstruction with maximum‐likelihood and Bayesian‐inference approaches revealed distinct clustering of R . asembonensis and uncultured Rickettsia spp. Furthermore, three nucleotide sequence types of R . asembonensis identified here were unique and not shared with isolates from other countries or host species, as demonstrated by phylogenetic and Templeton–Crandall–Sing network analyses. Conclusions: This work provides the first documentation of R . asembonensis in client‐owned urban dogs and cats in Thailand and highlights the need for increased awareness among veterinarians and pet owners, given its public health relevance.

Background: Haemoplasma (haemotropic Mycoplasma sp.) is an aetiological agent of infectious anaemia in several mammals, including cats and pigs. Blood cytology lacks sensitivity for detecting this infection, and information regarding its accuracy in Thailand is lacking. Thus, PCR has emerged as the test of choice. Recently, a new conventional PCR (cPCR) assay targeting the 16S rRNA gene (approximately 1000 bp) was established and used in various studies, but its diagnostic accuracy has not been verified. Objectives: This study compared the accuracy of blood cytology and 16S rRNA ‐based cPCR with the previously described cPCR assay targeting a partial fragment of the 16S rRNA gene (approximately 600 bp). Methods: In total, 216 cat and 569 pig samples were tested for haemoplasma infection using blood cytology, 1000‐bp cPCR, and 600‐bp cPCR. The diagnostic properties and predictive utility of blood cytology and 1000‐bp cPCR were assessed using 600‐bp cPCR as the reference. Results: In cats, blood cytology exhibited 23.68% sensitivity, 74.72% specificity and a poor level of agreement with 600‐bp cPCR, whereas 1000‐bp cPCR displayed 100.00% sensitivity and specificity and an almost perfect level of agreement with 600‐bp cPCR. In pigs, blood cytology displayed 34.23% sensitivity, 92.22% specificity and a fair level of agreement with 600‐bp cPCR, whereas the 1000‐bp cPCR assay displayed 94.14% sensitivity, 100% specificity and an almost perfect level of agreement with 600‐bp PCR. Conclusions: Blood cytology exhibited little utility in diagnosing haemoplasma infection in cats and pigs, indicating that molecular assays, such as 1000‐bp cPCR with almost perfect agreement and high diagnostic performances, should be used for diagnosing haemoplasma infection. Two cPCR assays used in this study have their own advantages. Therefore, the selection of a preferred assay depends on each researcher.

Bartonella bovis is an emerging ruminant pathogen with zoonotic potential. Although various Bartonella species have been detected in animals in Thailand, none have been reported in dairy cattle. We investigated the occurrence and genetic characteristics of Bartonella spp. in dairy cattle from central Thailand and examined associations with farm management practices. Blood samples were collected from 522 cattle on 43 farms in four provinces and examined for Bartonella DNA by PCR targeting the gltA , rpoB , and ribC genes. Sequencing, phylogenetic analyses, and nucleotide sequence type (ntST) network analyses were also performed. Risk factors were assessed using Fisher’s exact test and multivariable logistic regression. Bartonella DNA was detected in 4.21% of samples, with all positives identified as B. bovis . Univariable analysis showed significantly higher prevalence in small/medium‐scale farms and separate feeding systems. However, in the multivariable model, farm size showed a strong trend toward association with B. bovis detection, although the association did not reach statistical significance. The dominant gltA sequence type (ntST04) was detected across all farm sizes and feeding practices, whereas a peripheral variant (ntST02) differed by nine nucleotide substitutions from a ked‐associated Bartonella sequence (GenBank ID: OQ716819). Both rpoB and ribC networks revealed seven distinct groups that were closely related to the B. bovis reference sequences, with nucleotide identities of 99.42%–100% and 99.41%–100%, respectively. This study provides new molecular evidence of B. bovis circulation in the Thai dairy cattle population, highlighting the need for improved surveillance and biosecurity, particularly in small‐scale operations, to mitigate potential zoonotic risks within a One Health framework.

Poultry production in Thailand has expanded considerably and industrially; however, ectoparasite infestations in poultry farms could still occur. Information on ectoparasite prevalence in intensive poultry farms in Thailand is limited. This study investigated the current distribution and diversity of ectoparasites in commercial layer farms in central Thailand using two sampling methods: feather-picking and AviVetTM trapping. A total of 1,006 samples (507 feather and 499 trap samples) were collected from 28 poultry houses in 10 intensive farms across five provinces. Samples were examined microscopically, and the infestation status was recorded for each ectoparasite species. Seven taxa were identified, comprising three chewing lice species (Lipeurus caponis, Menacanthus stramineus, and Menopon gallinae) and four mite species (Dermanyssus gallinae, Megninia spp., Ornithonyssus bursa, and Pterolichus obtusus). Megninia spp. (44.0%) and P. obtusus (20.8%) were the most prevalent, whereas M. stramineus and O. bursa were rare (≤0.4%). No fleas or ticks were detected. Feather-picking yielded significantly higher detection rates than AviVetTM trapping for L. caponis, M. gallinae, Megninia spp., and P. obtusus (P<0.001 for all), while no significant method-related differences were found for M. stramineus, D. gallinae, or O. bursa. Spatial analysis was possible only for Megninia spp., which varied significantly among provinces and farms (P<0.001). This is the first report describing the diversity of ectoparasites collected using AviVetTM traps in intensive poultry farms in Thailand and provides baseline data to guide integrated control strategies in tropical poultry production systems.