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Scrub typhus is responsible for a large proportion of undifferentiated fevers in south-east Asia. The cellular tropism and pathophysiology of the causative agent, Orientia tsutsugamushi, remain poorly understood. We measured endothelial and leucocyte activation by soluble cell adhesion molecule enzyme-linked immunosorbent assays in 242 Lao and Thai patients with scrub or murine typhus, leptospirosis, dengue, typhoid and uncomplicated falciparum malaria on admission to hospital. Soluble E-selectin (sE-selectin) levels were lowest in dengue, sL-selectin highest in scrub typhus with a high sE-selectin to sL-selectin ratio in leptospirosis patients. In scrub typhus patients elevated sL-selectin levels correlated with the duration of skin rash ( P = 0·03) and the presence of eschar ( P = 0·03), elevated white blood cell (WBC) count ( P = 0·007), elevated lymphocyte ( P = 0·007) and neutrophil counts ( P = 0·015) and elevated levels of sE-selectin correlated with the duration of illness before admission ( P = 0·03), the presence of lymphadenopathy ( P = 0·033) and eschar ( P = 0·03), elevated WBC ( P = 0·005) and neutrophil counts ( P = 0·0003). In comparison, soluble selectin levels in murine typhus patients correlated only with elevated WBC counts ( P = 0·03 for sE-selectin and sL-selectin). Soluble intercellular adhesion molecule-1 and soluble vascular adhesion molecule-1 levels were not associated significantly with any clinical parameters in scrub or murine typhus patients. The data presented suggest mononuclear cell activation in scrub typhus. As adhesion molecules direct leucocyte migration and induce inflammatory and immune responses, this may represent O. tsutsugamushi tropism during early dissemination, or local immune activation within the eschar. [ABSTRACT FROM AUTHOR]

Two separate fatal outbreaks occurred in ornamental goldfish (Carassius auratus) farms, marked by clinical signs including depression, scale protrusion, massive mucus production, and mortality rates exceeding 50% were identified in Thailand. Detailed histological examination revealed extensive necrosis of hematopoietic tissues in kidneys and spleen, together with marked necrotizing branchitis and brachium hyperplasia. Furthermore, characteristic intranuclear inclusion bodies with margination of chromatin were observed in hematopoietic cells in the spleen and kidneys, and in gill epithelial cells. Conventional polymerase chain reaction (PCR) detected Cyprinid herpesvirus-2 (CyHV-2) DNA in the affected populations, with no presence of CyHV-1 or CyHV-3 DNA. Using quantitative PCR (qPCR), we found that viral DNA largely localized within the spleen and kidneys, followed by gills, heart, brain, and liver. In situ hybridization demonstrated CyHV-2 tropism, with localization identified in hematopoietic cells in the kidney and spleen, and in epithelial cells in the gill lamellae and skin. Apart from hematopoietic cells in kidneys and spleen, transmission electron microscopy confirmed herpesviral particles within the epithelial cells in the gills and skin of infected fish. Genomic analysis was conducted on partial genome sequences of CyHV-2 DNA polymerase and helicase genes, and the tandem repeats region were obtained and subsequently characterized using next generation sequencing-based approach. This data suggested that these two CyHV-2 Thai strains were nearly identical and closely related to other CyHV-2 strains found in Asia. Genomic analysis based on the helicase gene revealed that the CyHV-2 Thai strains were unique and distinct by creating monophyletic clade. Our findings report the first identification of CyHV-2 in Thailand for first time, and highlight its potential pathological implications. While these Thai sequences of CyHV-2 are indeed unique, further investigations are in progress to confirm the definitive role of this genetic variability in relation to its virulence. • Fatal outbreaks of ornamental goldfish (C. auratus) in association with CyHV-2 infection were firstly reported in Thailand • The presence of CyHV-2 was confirmed by real-time PCRs, in situ hybridization, and transmission electron microscopy. • CyHV-2 particles were identified in non-hematopoietic organs, suggesting broad-cellular tropism of the virus. • Phylogenetic analysis based on multiple regions of DNAPol and helicase genes indicated a unique topologic feature. [ABSTRACT FROM AUTHOR]

Tilapia culture is an essential protein-rich food production sector worldwide. The emergence of pathogens is sometimes associated with fatal outbreaks in tilapia, which dramatically slow production and result in severe economic losses. While tilapia lake virus (TiLV) infection has been associated with fatal diseases in tilapia, the novel tilapia parvovirus (TiPV) has been recently identified and reported to be associated with mass mortality events in tilapia farming. In this study, we identified the coinfection of a novel TiPV and TiLV in multiple independent tilapia farms in Thailand, thus causing significant losses. The full-length genomes of the TiPV were characterized, and a phylogenetic analysis was performed, indicating the genetic diversity of the TiPV and multiple amino acid mutations found in the structural protein VP1. Using the in situ hybridization (ISH) technique, TiPV was localized in the gills, heart, brain, liver, pancreas, spleen, intestine, kidney, eyes, and muscles of tilapia, with evidence of cellular tropism. The TiLV localization was confirmed using a dual ISH/immunohistochemistry protocol and transmission electron microscopy, which indicated a potential association with pathological alterations. Both TiPV and TiLV were successfully propagated in tilapia brain cells and the fish cell line E-11. This study also provided an indication of the potential cellular roles of the pathological features of TiPV coinfection with TiLV in red hybrid tilapia. Since mutations in the parvovirus structural protein led to virulence and extensive infection in susceptible hosts, several point mutations in the VP1 gene with amino acid signatures of TiPV found in tilapia in Thailand warrant future observations. Although the synergism between TiPV and TiLV coinfection remains undetermined, the contributory role of these two viruses requires intensive focus. Further investigations should lead to a suitable strategy for disease control. • Massive mortality events of TiPV coinfection with TiLV in multiple tilapia farms in Thailand were reported. • The presence of TiPV was confirmed by PCRs, virus isolation, ISH, and TEM. • Dual identification of TiPV and TiLV was confirmed with the dual ISH/IHC assay, and associated with pathological lesions. • Full-length genome and phylogenetic analysis of TiPV demonstrated genetic diversity and mutations within the VP1 gene. [ABSTRACT FROM AUTHOR]

Carnivore protoparvovirus-1 (CPPV-1), a viral species containing feline panleukopenia virus (FPV) and canine parvovirus (CPV) variants, are widely spread among domestic and wild carnivores causing systemic fatal diseases. Wild fishing cats (Prionailurus viverrinus), a globally vulnerable species, have been found dead. Postmortem examination of the carcasses revealed lesions in intestine, spleen and kidney. CPPV-1 antigen identification in these tissues, using polymerase chain reaction (PCR) and immunohistochemistry (IHC), supported the infection by the virus. PCR- and IHC-positivity in kidney tissues revealed atypical localization of the virus while in situ hybridization (ISH) and transmission electron microscopy (TEM) with the pop-off technique confirmed the first description of viral localization in kidneys. Complete genome characterization and deduced amino acid analysis of the obtained CPPV-1 from the fishing cats revealed FPV as a causative agent. The detected FPV sequences showed amino acid mutations at I566M and M569R in the capsid protein. Phylogenetic and evolutionary analyses of complete coding genome sequences revealed that the fishing cat CPPV-1 genomes are genetically clustered to the FPV genomes isolated from domestic cats in Thailand. Since the 1970s, these genomes have also been shown to share a genetic evolution with Chinese FPV strains. This study is the first evidence of CPPV-1 infection in fishing cats and it is the first to show its localization in the kidneys. These findings support the multi-host range of this parvovirus and suggest fatal CPPV-1 infections may result in other vulnerable wild carnivores. [ABSTRACT FROM AUTHOR]

Carnivore protoparvovirus-1 (CPPV-1) infection has been reported frequently in both domestic and wildlife species including wild carnivores. Fifty-five captive small Indian civets (Viverricula indica), farmed for perfume production in Eastern Thailand, showed clinical signs of acute bloody diarrhea, anorexia, vomiting, circling, and seizures. The disease spread within the farm and resulted in the death of 38 of the 55 civets (69% mortality) within a month. Fecal swabs were collected from the 17 surviving civets, and necropsy was performed on 7 of the dead civets. Pathologic findings were severe hemorrhagic gastroenteritis with generalized lymphadenopathy. CPPV-1 was identified in both fecal swabs and postmortem samples by species-specific polymerase chain reaction. Further whole-gene sequencing and restriction fragment length polymorphism analysis suggested feline panleukopenia virus (FPV) as the causative agent. The viral tropism and tissue distribution were confirmed by immunohistochemistry, with immunolabeling in the cytoplasm and nucleus of small intestinal crypt epithelial cells, villous enterocytes, histiocytes in lymphoid tissues, myenteric nerve plexuses, and cerebral and cerebellar neurons. Phylogenetic analysis of civet-derived CPPV-1 indicated a genetic similarity close to the FPV HH-1/86 strain detected in a jaguar (Panthera onca) in China. To our knowledge, this mass die-off of civets is the first evidence of disease associated with CPPV-1 infection in the subfamily Viverrinae. These findings support the multi-host range of parvovirus infection and raises awareness for CPPV-1 disease outbreaks in wildlife species. [ABSTRACT FROM AUTHOR]

Background: Feline morbillivirus (FeMV) has been discovered in domestic cats associated with tubulointerstitial nephritis, but FeMV is also detected in healthy cats. This research aimed to identify and characterize the FeMV strains detected in a Thai cat population. Results: Two-hundred and ninety-two samples (131 urine and 161 blood) derived from 261 cats (61 sheltered and 200 household cats) were included for investigating the FeMV prevalence using real-time reverse transcription PCR. The overall prevalence of FeMV detection was 11.9% (31/261) among both samples, which accounted for 14.5% (19/131) and 7.5% (12/161) of the urine and blood samples, respectively. Among the FeMV-PCR positive cats, the FeMV-detected prevalence was insignificantly associated with healthy cats (58.1%; 18/31) or urologic cats (41.9%; 13/31). Full-length genome analysis of these FeMV-Thai strains revealed that their genomes clustered together in the FeMV-1A clade with up to 98.5% nucleotide identity. Selective pressure analysis showed that overall FeMV-1 has undergone negative selection, while positive selection sites were more frequently observed in the phosphoprotein gene. Conclusions: The detected FeMV infections in the Thai cat population were not correlated with urologic disorders, although the virus was more detectable in urine samples. The genetic patterns among the FeMV-1 Thai strains were more consistent. A large-scale study of FeMV in Thai cat samples is needed for further elucidation. [ABSTRACT FROM AUTHOR]