Background and Aim: An apicomplexan protozoan parasite, namely, Theileria, primarily causes theileriosis in cattle worldwide. The virulence of the disease has been neglected because of it's low pathogenicity. However, the disease can have a substantial effect, depending on the virulence of the species, low host immunity, and coinfection. In Thailand, the molecular detection of Theileria infection in bullfighting cattle and its hematological alterations have not been reported. Thus, this study aimed to identify Theileria species in bullfighting cattle in Thailand. Materials and Methods: Blood samples were collected from bullfighting cattle presented at the Prince of Songkla University Animal Hospital and were determined on the basis of hematological evaluation and DNA extraction. Molecular detection using the 18s rRNA and merozoite surface antigen genes was conducted for Theileria spp. and Theileria orientalis, respectively. In addition, bidirectional sequencing of the positive samples was performed. Hematological alterations between Theileria infected and uninfected groups were statistically evaluated. Results: The levels of Theileria spp. and T. orientalis infection in bullfighting cattle were 44.62% (58/130) and 41.54% (54/130), respectively. Theileria orientalis, Theileria sinensis, and Theileria spp. infections were identified in bullfighting cattle samples. Hematological evaluation indicated that the red blood cell (RBC) level was significantly lower in Theileria-infected cattle. Conclusion: This study was the first to use molecular techniques in the identification of Theileria infection in bullfighting cattle in Thailand, with nearly one-half of the study population infected. Theileria infection in bullfighting cattle altered the RBC level, resulting in anemia. Therefore, tick control measures should be promoted.

Piscine intestinal Cryptosporidium infection is a known cause of severe illness and mortality in juvenile Asian sea bass, with inflammation playing a central role. This inflammation triggers the generation of reactive oxygen species (ROS), leading to irreversible DNA damage and activation of apoptosis pathways. However, the specific impact of inflammation on ROS production, DNA damage, and apoptosis in this context remains unclear. This study investigated the pathogenic role of inflammation and ROS in causing DNA damage and cell apoptosis in piscine intestinal cryptosporidiosis. Forty‐four intestinal samples from 60‐ and 90‐day juvenile Asian sea bass were divided into four groups based on Cryptosporidium infection status. Histopathological evaluation and immunofluorescent analysis were conducted to assess ROS production, DNA damage, and cellular apoptosis markers. Results showed significantly higher inflammatory cell infiltration, intracellular ROS production, DNA damage, and cellular apoptosis in 60‐day infected fish compared to 90‐day infected fish. These findings underscore distinct responses in juvenile Asian sea bass to piscine intestinal cryptosporidiosis, highlighting severe inflammation, oxidative DNA damage, and cellular apoptosis, particularly in younger fish.

Background and Aim: Cetaceans and sirenians are endangered marine mammals that are threatened by stranding and mortality. In Thailand’s Andaman Sea, limited data exist on the causes and patterns of these events. This retrospective study investigated the characterization and underlying causes of cetacean and sirenian mortality events in the Andaman Sea from 2018 to 2023 using information from the Department of Marine and Coastal Resources, Thailand. Materials and Methods: Data on 363 stranded marine mammals, including both live and dead strandings, species types, carcass condition, and necropsy findings and diagnoses, were gathered and analyzed to classify and determine the main factors contributing to mortality, encompassing both direct human-related and non-direct human-related causes. Results: From 2018 to 2023, 231 cetaceans and 132 sirenians were documented, representing six families and 19 species. Of these animals, 18.18% (66/363) were stranded alive and 81.81% (297/363) were found dead. The most common species were dugong (Dugong dugon) and Indo-Pacific humpback dolphin (Sousa chinensis). Detailed postmortem analyses of 107 specimens showed that 17.76% (19/107) of deaths were anthropogenic, affecting 8 sirenians and 11 cetaceans. The majority of deaths were non-anthropogenic, involving 34 sirenians and 54 cetaceans. In addition, 223 stranded animals could not be fully assessed due to carcass condition. Conclusion: A high cetacean and sirenian mortality rate in the Andaman Sea can be attributed to non-anthropogenic factors. The dugong and Indo-Pacific humpback dolphin were the most frequently encountered species. This report enhances our understanding of marine mammal mortality in Thailand and underscores the need for improved health management and diagnostic responses. Keywords: dolphin, dugong, marine mammal, necropsy, stranding whale.

Objective: The Spotted Scat Scatophagus argus, particularly in aquaculture, is commonly affected by intestinal parasitic infections that impact its health and growth. Filisoma spp., an acanthocephalan parasite, and Cryptosporidium spp. cause intestinal inflammation in various marine fish; however, infections with Cryptosporidium spp. or co-infection with these parasites have not been identified in Spotted Scat. Methods: Host–parasite interactions in fish, including the inflammatory responses of the intestine, were investigated in 32 cultured Spotted Scat from Songkhla, Thailand. The study used parasitological examination, including polymerase chain reaction and nucleotide sequencing of the ITS1 and ITS2 regions of the ribosomal RNA gene for acanthocephalans and the 18S ribosomal RNA gene for Cryptosporidium. Additionally, histopathology and immunohistochemistry for interleukin-4 expression were performed. Results: Most of the infected fish showed no significant clinical signs, with postmortem findings of hemorrhagic, congested, and edematous intestines. Parasitological analysis revealed that 84.37% of the fish were infected, with 9.37% having a single helminth infection, 40.62% being infected with coccidia, 34.37% having mixed infections with both parasites, and 15.62% of the fish being free from intestinal parasites. Polymerase chain reaction and nucleotide sequencing indicated that F. argusum and C. bollandi were the parasites involved. Histopathology showed increased inflammatory cell infiltrations, particularly eosinophilic granule cells and mononuclear cells, as well as higher levels of histopathological changes (vascular congestion, tissue necrosis, and epithelial desquamation) in the single F. argusum infection and co-infection with F. argusum and C. bollandi compared with C. bollandi infection alone. Similarly, significantly elevated interleukin-4 expression in the intestines, indicating a strong proinflammatory immune response, was observed in these groups. Conclusions: This study highlights the detrimental effects of F. argusum, regardless of whether it is a single or concomitant infection, which may impact the health of fish.

Dugongs (Dugong dugon), classified as vulnerable marine mammals, are increasingly impacted by infectious diseases, yet the role of septicemia and disseminated intravascular coagulation (DIC) in their mortality remains uncharacterized. This study aimed to investigate the pathological and microbiological features associated with an acute mortality event in a juvenile dugong during rehabilitation in southern Thailand. Comprehensive histopathological and microbiological analyses were conducted on tissue samples collected postmortem. Bacterial isolation and identification were performed using standard culture techniques and the VITEK-2 system. Histological examination revealed multisystemic lesions, including fibrin thrombi, hemorrhage, hepatocellular degeneration, pancreatic necrosis, lymphoid depletion, and neuronal damage. Oxidative stress and DNA damage were confirmed in brain tissues through immunofluorescence detection of 4-hydroxynonenal (4-HNE) and 8-hydroxy-2′-deoxyguanosine (8-oxodG). Achromobacter xylosoxidans, an opportunistic pathogen, was isolated from multiple organs, consistent with acute systemic infection. These findings represent the first evidence of septicemia-associated DIC in dugongs caused by A. xylosoxidans, highlighting a previously undocumented cause of mortality in dugongs. The results emphasize the role of opportunistic bacteria in triggering oxidative damage and coagulopathy and underscore the importance of early detection and targeted therapeutic strategies to improve survival in stranded or rehabilitated dugongs.