Canine bufavirus (Carnivore protoparvovirus-3) infection in dogs with respiratory disease.

Canine bufavirus (CBuV) or Carnivore protoparvovirus-3, a nonenveloped DNA virus belonging to the genus Protoparvovirus, family Parvoviridae, has been identified in dogs with respiratory and enteric diseases. Although CBuV detection has been reported in multiple countries, descriptions of pathologic findings associated with infection have not yet been provided. In this study, the authors necropsied 14 dogs (12 puppies and 2 adult dogs) from a breeding colony that died during multiple outbreaks of respiratory diseases. Postmortem investigations revealed extensive bronchointerstitial pneumonia with segmental type II pneumocyte hyperplasia in all necropsied puppies but less severe lesions in adults. With negative results of common pathogen detection by ancillary testing, CBuV DNA was identified in all investigated dogs using a polymerase chain reaction (PCR). Quantitative PCR demonstrated CBuV DNA in several tissues, and in situ hybridization (ISH) indicated CBuV tissue localization in the lung, tracheobronchial lymph node, and spinal cord, suggesting hematogenous spread. Dual CBuV ISH and cellular-specific immunohistochemistry were used to determine the cellular tropism of the virus in the lung and tracheobronchial lymph node, demonstrating viral localization in various cell types, including B-cells, macrophages, and type II pneumocytes, but not T-cells. Three complete CBuV sequences were successfully characterized and revealed that they clustered with the CBuV sequences obtained from dogs with respiratory disease in Hungary. No additional cases were identified in small numbers of healthy dogs. Although association of the bufavirus with enteric disease remains to be determined, a contributory role of CBuV in canine respiratory disease is possible.

Renal epitheliotropism of feline morbillivirus in two cats.

The association of feline morbillivirus (FeMV) with kidney disease in cats is controversial. Two cats with a history of severe hematuria had eosinophilic inclusion-like bodies in the renal tubular epithelial cells, without any inflammatory cellular reaction. Ultrastructurally, aggregations of electron-dense viral-like particles were found where the inclusion-like bodies were located. Immunohistochemistry (IHC) using antibodies against FeMV matrix protein labeled these inclusion-like bodies, and also labeled the cytoplasm of tracheal and bronchiolar epithelial cells, and lymphocytes and macrophages in spleen and mesenteric lymph node. Using double IHC, FeMV antigen was detected in astroglia and oligodendroglia but not in microglia. Phylogenetic characterization of the fusion and hemagglutinin gene sequences revealed FeMV-1A genotypes in both cats. These findings indicated an active viral infection with FeMV. We propose that FeMV is a renal epitheliotropic virus and also localizes in various other tissues.

Lokivetmab therapy for pruritus in a dog with cutaneous mastocytosis.

BACKGROUND: Cutaneous mastocytosis (CM) is a rare disease of dogs characterized by rash, pruritus and proliferation of mast cells in the skin. Oral H1 antihistamines are recommended as the treatment to control pruritus. HYPOTHESIS/OBJECTIVE: To describe the effective treatment of pruritus associated with CM with lokivetmab in one dog. ANIMAL: A 4-year-old, spayed female cross-bred dog presented with severely pruritic, erythematous to pigmented macules and papules involving the ventral abdomen, interdigital skin, perivulval area and both pinnae; the pruritus had been unresponsive to treatment with antihistamines, prednisone and ciclosporin. METHODS AND MATERIALS: Complete blood count and serum biochemistry, abdominal ultrasound, blood smear and skin cytological evaluation, PCR, histopathological and immunohistochemical examination of skin biopsies. RESULTS: Skin cytological evaluation revealed high numbers of uniform, heavily granulated mast cells; histopathological findings showed focal dermal proliferations of well-differentiated, uniform mast cells consistent with a low-grade mast cell tumour (MCT). Clinical staging revealed that the disease was confined to the skin. Mutations of c-kit exon 8 and 11 were not detected. Treatment was initiated with anti-canine-interleukin (IL)-31 monoclonal antibody lokivetmab; antihistamines were continued. The dog's pruritus resolved within seven days and was maintained in remission over 15 months with once monthly lokivetmab injections; the skin lesions improved but did not resolve. CONCLUSION AND CLINICAL IMPORTANCE: Lokivetmab treatment was effective in resolving and maintaining pruritus remission in this dog with widespread cutaneous mast cell disease. Whether CM in dogs represent a separate entity that should be distinguished from a low-grade MCT requires further investigation.

Single nucleotide polymorphism profiles of canine T-cell and null-cell lymphomas.

Background: The histopathological classification of T-cell lymphoma (TCL) in humans has distinctive mutational genotyping that suggests different lymphomagenesis. A similar concept is assumed to be observed in dogs with different TCL phenotypes. Objective: This study aimed to identify the previously reported single-nucleotide polymorphisms (SNPs) in both human beings and dogs in canine TCLs and null-cell lymphomas (NCLs) and to design compatible oligonucleotides from each variant based on the multiplex polymerase chain reaction. Methods: Genomic DNA was extracted from 68 tumor specimens (62 TCLs and 6 NCLs) and 5 buffy coat samples from dogs with TCL. Four TCL subtypes and NCL were analyzed in 44 SNPs from 21 genes using the MassARRAY. Results: The greatest incidences of SNPs observed in all TCL subtypes and NCL ware SATB1 c.1259A > C, KIT c.1275A > G, SEL1L c.2040 + 200C > G, and TP53 c.1024C > T, respectively. Some SNP locations were statistically significant associated with NCL, including MYC p.S75F (p = 0.0003), TP53 p.I149N (p = 0.030), PDCD1 p.F37LX (p = 0.012), and POT1 p.R583* (p = 0.012). Conclusion: Each TCL histological subtype and NCL are likely to contain distinctive mutational genetic profiles, which might play a role in lymphoma gene-risk factors and might be useful for selecting therapeutic target drugs for each canine patient.

Evolutionary dynamics of canine kobuvirus in Vietnam and Thailand reveal the evidence of viral ability to evade host immunity.

Canine kobuvirus (CaKoV) is a pathogen associated with canine gastrointestinal disease (GID). This study examined 327 rectal swabs (RS), including 113 from Vietnam (46 healthy, 67 with GID) and 214 from Thailand (107 healthy and 107 with GID). CaKoV was detected in both countries, with prevalences of 28.3% (33/113) in Vietnam and 7.9% (17/214) in Thailand. Additionally, CaKoV was found in both dogs with diarrhea and healthy dogs. CaKoV was mainly found in puppies under six months of age (30.8%). Co-detection with other canine viruses were also observed. The complete coding sequence (CDS) of nine Vietnamese and four Thai CaKoV strains were characterized. Phylogenetic analysis revealed a close genetic relationship between Vietnamese and Thai CaKoV strains, which were related to the Chinese strains. CDS analysis indicated a distinct lineage for two Vietnamese CaKoV strains. Selective pressure analysis on the viral capsid (VP1) region showed negative selection, with potential positive selection sites on B-cell epitopes. This study, the first of its kind in Vietnam, provides insights into CaKoV prevalence in dogs of different ages and healthy statuses, updates CaKoV occurrence in Thailand, and sheds light on its molecular characteristics and immune evasion strategies.

Natural SARS-CoV-2 infection in dogs: Determination of viral loads, distributions, localizations, and pathology.

Instances of reverse zoonosis involving severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been documented in both controlled experiments and spontaneous cases. Although dogs are susceptible to infection, clinical significance is limited to mild or asymptomatic. Here, we investigate the fatal cases of natural SARS-CoV-2 infection in dogs in Thailand. Pathological findings of SARS-CoV-2-infected dogs reveal severe diffuse alveolar damage, pulmonary hyalinization and fibrosis, and syncytial formation, together with minor lesions in brain and kidney. Employing reverse transcription-digital PCR, substantial viral loads of SARS-CoV-2 were detected in lung, kidney, brain, trachea, tonsil, tracheobronchial lymph node, liver, and intestine, respectively. Localization of SARS-CoV-2 within various tissues was examined through immunohistochemistry (IHC), where the co-localization of the viral spike protein and the angiotensin-converting enzyme 2 (ACE2) receptor was illustrated using double IHC. SARS-CoV-2 localization was markedly identified in the epithelial cells of the lung, trachea, intestine and kidneys, and moderately presented in the salivary gland and gall bladder, where the co-localization with the ACE2 was also evident. Neurons in the brainstem where exhibited lymphocytic perivascular cuffing were also found to be positive for SARS-CoV-2 in IHC testing, despite lacking ACE2 receptor expression. In addition, SARS-CoV-2 replication within the lungs of infected dogs was confirmed by transmission electron microscopy, visualizing free viral particles within the cytosol or the endoplasmic reticulum of syncytial cells within the lung. This study considerably expanded on the knowledge of the pathology associated with natural SARS-CoV-2 infection in dogs, a scenario that is relatively infrequent but occasionally leads to fatal outcome. Furthermore, these findings suggest the potential utility of dogs as a model for studying SARS-CoV-2 infection in humans, warranting further investigation.

Environmental management procedures following fatal melioidosis in a captive chimpanzee (Pan troglodytes).

A 40-yr-old male captive chimpanzee (Pan troglodytes) presented with depression and anorexia for 7 days. The tentative diagnosis, following a physical examination under anesthesia, was pneumonia with sepsis. Despite antibiotic treatment and supportive care the chimpanzee died a week following presentation. Gross pathology confirmed severe purulent pneumonia and diffuse hepatosplenic abscesses. Detected in serum at the time of the initial examination, the melioidosis serum antibody titer was elevated (> 1:512). Soil samples were collected from three sites in the exhibit at three depths of 5, 15, and 30 cm. By direct and enrichment culture, positive cultures for Burkholderia pseudomallei were found at 5 and 15 cm in one site. The other two sites were positive by enrichment culture at the depth of 5 cm. To prevent disease in the remaining seven troop members, they were relocated to permit a soil treatment with calcium oxide. The exhibit remained empty for approximately 1 yr before the chimpanzees were returned. During that period, the soil in the exhibit area was again cultured as before and all samples were negative for B. pseudomallei. Following the soil treatment in the exhibit, all chimpanzees have remained free of clinical signs consistent with melioidosis.

Carnivore chaphamaparvovirus-1 (CaChPV-1) infection in diarrheic dogs reveals viral endotheliotropism in intestine and lung.

BACKGROUND: Carnivore chaphamaparvovirus-1 (CaChPV-1) is a parvovirus identified in dogs and association of infection with diarrhea is controversial. Information on whether tissue tropism persists is lacking. OBJECTIVES: To determine the disease association of CaChPV-1 in dogs with diarrhea and to investigate viral tropism and genetic diversity. ANIMALS AND METHODS: CaChPV-1 infection was investigated in five recently deceased puppies and designed a retrospective study to determine whether the presence of CaChPV-1 is associated with diarrhea. The retrospective study was conducted in 137 intestinal tissue samples and 168 fecal samples obtained from 305 dogs. CaChPV-1 tissue localization was determined using in situ hybridization, and CaChPV-1 complete genomes obtained from dead puppies and retrospective study were sequenced and analyzed. RESULTS: CaChPV-1 was detected in 6.56% (20/305) of tested dogs, including 14 diarrheic- and 6 non-diarrheic dogs, and was significant in puppies with diarrhea (p = 0.048). Among the CaChPV-1-positive diarrheic dogs, one sample was obtained from intestinal tissue and 13 samples were fecal samples. However, six CaChPV-1 positive non-diarrheic dogs were based on fecal samples but not on intestinal tissue. Within the age range, the presence of CaChPV-1 was significant in puppies (p < 0.00001) and was mainly localized in the stromal and endothelial cells of intestinal villi and pulmonary alveoli. Phylogenetic analysis indicated genetic diversity of CaChPV-1 Thai strains that were mostly clustered within the sequences found in China. CONCLUSIONS: Although definitive pathogenesis of CaChPV-1 remains undetermined, this study provides evidence supporting that CaChPV-1 localizes in canine cells and could play a potential role as an enteric pathogen.

Epidemiology of Chlamydia sp. infection in farmed Siamese crocodiles (Crocodylus siamensis) in Thailand.

BACKGROUND: Although Chlamydia sp. causes widespread disease outbreaks in juvenile crocodiles in Thailand, data regarding the epidemiology, and risk factors of such infections are limited. The aim of this study was to investigate the prevalence and possible risk factors associated with Chlamydia sp. infections on Siamese crocodile (Crocodylus siamensis) farms in Thailand. A cross-sectional study was conducted from July to December 2019. Samples were collected from 40 farms across six regions in Thailand. Conjunctival, pharyngeal, and cloacal swab samples were analyzed for Chlamydiaceae nucleic acids using semi-nested PCR followed by phylogenetic analysis based on the ompA gene fragment. Risk factors of infection were analyzed using chi-square and univariate regression to calculate odds ratios. RESULTS: The prevalence of Chlamydia sp. infection across all regions was 65%. The ompA phylogenetic analysis showed that Chlamydia sp. detected in this study was genetically closely related to Chlamydia crocodili and Chlamydia caviae. The risk factors for infection were water source, reusing treated wastewater from the treatment pond, not disposing of leftover food, low frequency of water replacement in the enclosure of juvenile crocodiles, and lack of water replacement after the death of a crocodile. CONCLUSION: The prevalence of Chlamydia sp. infection in farmed crocodiles in Thailand was 65% during the study period. Cloacal swabs were superior to conjunctival and pharyngeal swabs due to their higher sensitivity in detecting Chlamydia sp., as well as their lower invasiveness. Good management and biosecurity in crocodile farming can reduce the risk of Chlamydia sp.

Case report: Mature extragonadal teratoma at the proximal part of the tail in a kitten.

An 8-month-old, intact male, domestic shorthair cat was referred for a mass on the proximal ventral part of the tail which had been found since the animal was born, and due to the presence of a linear fissure with rows of ectopic teeth, the veterinarian suspected that the mass had recently ruptured. Tail amputation was elected and the entire mass was successfully surgically excised. From the gross examination, this mass had an open cyst-like structure with a prominent area composed of hair, teeth, and bone. Histopathology revealed two components of germinal layers including hair follicles, adnexal tissue, neural tissue, teeth, muscle, fat, bone, and lymphatic vessels. The histopathological diagnosis was consistent to mature teratoma. Although, complete excision could not be definitively confirmed histologically, this kitten is currently well and has not developed any recurrent mass at the surgical site after 2 years of post-operation.

Japanese encephalitis virus infection in meerkats (Suricata suricatta).

Japanese encephalitis virus (JEV) infection has been recognized as a serious disease in humans. Wildlife animal infections due to JEV have not been well described. This study identified JEV infection in two deceased meerkats in Thailand, with clinical signs of neurological disease. Histopathology of brains revealed severe lymphoplasmacytic necrotizing meningoencephalitis, while similar inflammation was observed in the lung and liver. Partial JEV sequences were identified from the formalin-fixed paraffin-embedded-derived brain sections of two meerkats and were found to be genetically similar to a JEV strain detected in China but not from a local strain. Using immunohistochemistry, the virus was identified in neurons and glial cells, and also found in bronchial glands, Kupffer's cells in liver, lymphocytes in the spleen and pancreatic acini, which suggests extraneural infection. Transmission electron microscopy confirmed the presence of spheroid viral particles in the lungs. These findings may suggest that infection of extraneural organs in meerkats is similar to that described in JEV-infected humans. In conclusion, this study identified the first JEV infection in meerkats as an interesting case study. The JEV should be considered as an important differential diagnosis in meerkats with encephalitis. Further surveillance on JEV infection in meerkats and other wildlife species in a large cohort is needed in the future study.

Evaluation of 41 single nucleotide polymorphisms in canine diffuse large B-cell lymphomas using MassARRAY.

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of lymphoma in dogs with a multicentric form. This study aimed to assemble 41 variants of the previously reported genes and to investigate these variants in canine DLBCL using the Agena MassARRAY platform. These variants were chosen based on the high prevalence observed in canine B- and T-cell lymphomas, their significance for target therapy, and compatibility for multiplex PCR amplification. Lymph node biopsy was performed from 60 dogs with B-cell lymphoma comprising 47 purebred and 13 crossbred dogs. All dogs presented single nucleotide polymorphisms (SNPs) at HYAL4 and SATB1 genes. The lesser mutual SNPs were observed at SEL1L, excluding a cocker spaniel, and c-Kit, with the exception of a pug and a French bulldog. Even though no statistical association was noted between each SNP and dog breed, purebreds were 3.88 times more likely to have a SNP at FLT3 rs852342480 (95%CI 0.50-45.03, p = 0.26), 3.64 times at TRAF3 F306X (95%CI 0.58-42.50, p = 0.43) and 2.66 times at TRAF3 E303EX (95%CI 0.56-13.12, p = 0.31). Also, DLBCL dogs (CHOP-based treatment) with c-Kit T425= had a poorer prognosis with shorter median overall survival times (OST) than dogs with the wild type. Dogs treated with COP chemotherapy and contained 3-5 variants at SEL1L were associated with decreased median OST. Therefore, this SNP's lymphoma panel provides valuable information that we can use to outline a prognosis and develop a treatment plan for the targeted therapy of each dog.

Naturally acquired feline bocavirus type 1 and 3 infections in cats with neurologic deficits.

Feline bocaviruses (FBoVs) have been recognized as novel feline pathogens associated with gastrointestinal diseases. Although bocavirus infections in humans and animals present a broad range of clinical symptoms including neurologic diseases, the neuropathology caused by FBoV infection in cats is unknown. This study aims to investigate the presence of bocavirus in the brain samples of 78 cats showing neurologic deficits and 41 healthy cats using polymerase chain reaction (PCR) and to present the pathological findings of FBoV infection in brain tissues. Only five (6.41%, five out of 78) cats with neurological deficit were FBoV positive on PCR screening and were characterized as FBoV-1 (four out of five) and FBoV-3 (one out of five) by sequencing. Among FBoV-positive cases, viral DNA were detected by PCR in the cerebrum and brain stem of all FBoV-positive cases and rarely detected in the cerebellum of some cases. Histologically, all FBoV-positive cases revealed a variety of inflammatory responses. Among these, 80% (four out of five cases) showed multifocal neuronal vacuolation, mainly found in the cerebrum and brain stem. Eosinophilic inclusion-like materials were found within the nuclei of glial cells in the FBoV-3-positive case. In situ hybridization revealed FBoV DNA in oligodendroglia and vacuolated neurons detected using dual labelling with Olig-2 and NeuN immunohistochemistry, respectively. Transmission electron microscopy confirmed the presence of FBoV-3 virions in the nuclei of glial cells. Apart from localization in brain tissues, the FBoV DNA were also detected in multiple lymph nodes (five out of five) and some intestines (two out of five) of such positive cases, suggesting both parenteral and enteral infections. Complete genome sequence analysis revealed genetic diversity of detected FBoV-1, which were closely related to the strains found in China and Hong Kong, while the detected FBoV-3 presented distant monophyletic clade to previously detected FBoV-3 sequences. The FBoVs, together, should be considered a neurotropic virus and a possible cause for neuronal vacuolation in cats with neurologic deficits.

Feline morbillivirus-1 in dogs with respiratory diseases.

Feline morbillivirus-1 (FeMV-1) is a viral pathogen associated with kidney disease in domestic cats and wild felids. We initially identified the FeMV-1 from the lung of a necropsied dog with severe pulmonary disease by the reverse transcription polymerase chain reaction (RT-PCR). Thereafter, we investigated FeMV-1 in nasal and oral swab samples from 73 healthy and 113 dogs with respiratory illnesses. We found polymerase chain reaction (PCR)-positive FeMV-1 from only 14/113 (12.39%) dogs with respiratory disease (p = .001). Of these 14 dogs, six were co-infected with other canine respiratory viruses (6/14; 42.86%). Two independent immunohistochemistry procedures, using antibodies against matrix and phosphoprotein of FeMV-1, confirmed the presence of FeMV-1 in lung tissues of two necropsied dogs (out of a total of 22 dogs, 9.09%) that died from respiratory disease. This finding corresponded to transmission electron microscopy findings that paramyxoviral particles exist in lung epithelia. FeMV-1 antigen localization was also evident in the kidney, lymphoid and brain tissues of two deceased dogs. FeMV-1 was successfully isolated from a necropsied dog and from two living dogs, all with respiratory illnesses, which supports FeMV infection in dogs. The detection of FeMV-1 in dog tissues expands the known tropism of this virus to a non-felid host. Our findings indicate that FeMV-1, alone or in co-infection with other viral pathogens, might contribute to respiratory illness and death in dogs.

Domestic cat hepadnavirus associated with hepatopathy in cats: A retrospective study.

BACKGROUND: Whether domestic cat hepadnavirus (DCH) infection is associated with clinical disease remains to be determined. OBJECTIVES: To determine the relationship between DCH detection, hematology, serum bichemistry and liver histology in DCH-positive cats. ANIMALS: One thousand twenty-two cats in Thailand without concurrent diseases and not undergoing treatments adversely affecting the liver. METHODS: Retrospective cross-sectional study. Samples derived from cats with concurrent virus detection were excluded. DCH detection was determined in blood and fresh-frozen liver by quantitative polymerase chain reaction (qPCR) and further investigated in liver sections showing histological parenchymal disorders (HPD) and normal liver (HNL) using in situ hybridization (ISH). Proliferative/apoptotic activities were determined using immunohistochemistry and ISH panels. Biochemical variables and risk factors for DCH infection were investigated. RESULTS: Six hundred sixty-one (557 blood and 119 liver samples) cats were included. DCH was detected in 18.50% (103/557), 13.85% (9/65), and 3.70% (2/54) of the blood, HPD, and HNL groups, respectively. Cats with DCH revealed abnormally high activity of aspartate aminotransferase (AST) (P = .001) and alanine aminotransferase (ALT) (P < .001). Among DCH-positive HPD case 2/9 an 7/9 were acute and chronic hepatitis, of which 4/7 had hepatitis. Log viral copy number (LVCN) was positively correlated with ALT (P < .001), triglyceride (P < .001), and gamma-glutamyl transpeptidase (GGT) (P = .022). The LVCN also had a positive association with degree of hepatitis (P < .05). There was hepatocyte proliferation activity in DHC positive cats. CONCLUSION AND CLINICAL IMPORTANCE: Domestic cat hepadnavirus infection was associated with high serum activity of liver enzymes and chronic lymphoplasmacytic hepatitis (LPH).

Molecular and Pathological Investigations of Selected Viral Neuropathogens in Rabies-Negative Brains of Cats and Dogs Revealed Neurotropism of Carnivore Protoparvovirus-1.

Throughout the year, the Thai Red Cross Society (TRCS), Bangkok, Thailand, received more than 100 animals that died of suspected rabies due to neurological clinical signs. Concerning the role of viral infection in the brain in the outcome of neurological diseases in cats and dogs, a comprehensive study was conducted of 107 brain samples of cats and dogs submitted to the TRCS from August 2019 to August 2020. Selective molecular screening using conventional polymerase chain reaction (PCR) and reverse transcription PCR targeting nine viral pathogens was employed in addition to histopathological investigations. The results showed that carnivore protoparvovirus-1 (CPPV-1) was detected in 18.69% of the cats and dogs sampled (20/107). These results were found in young and old animals; the brain tissue did not show any pathological changes suggesting encephalitis or cerebellar hypoplasia. In addition, feline calicivirus, feline alphaherpesvirus-1, feline coronavirus, and canine distemper virus were also detected, providing a broader range of potential viral infections to consider in the clinical manifestation of neurological disorders in companion animals. The detection of all pathogens was confirmed by the localization of each viral antigen in various resident brain cells using immunohistochemistry. A unique L582S amino acid substitution of the non-structural protein 1 gene coding sequence, speculated to be associated with the neurotropism of CPPV-1 in cats and dogs, was not evident. In conclusion, this study revealed a noteworthy neurotropism of CPPV-1 in both cats and dogs without neurological lesions.

Disseminated Haemophagocytic Histiocytic Sarcoma in an African Pygmy Hedgehog (Atelerix albiventris).

A 3-year-old intact male African pygmy hedgehog (Atelerix albiventris) was found dead shortly after clinical onset of screaming, aerophagia and lethargy. On gross examination, the spleen was dark red and friable, and the liver was markedly enlarged with a prominent lobular pattern and multiple white nodules. Histopathological examination of liver and spleen revealed dense infiltrates of highly pleomorphic neoplastic, round to polyhedral cells with overt erythrophagocytosis. Similar neoplastic cells were found in the sinuses of the abdominal lymph nodes and in blood vessels in the heart, lung, brain and kidneys. Immunolabelling for CD204 confirmed the histiocytic origin of the neoplastic cells. To our knowledge, this is the first report of a disseminated haemophagocytic histiocytic sarcoma in a hedgehog.

Coinfection of Chlamydia spp. and herpesvirus in juvenile farmed Siamese crocodiles (Crocodylus siamensis) in Thailand.

BACKGROUND AND AIM: For a decade, chlamydial and herpesvirus infections have caused significant morbidity and mortality in farmed crocodiles. In September 2017, a total of 160 juvenile freshwater Siamese crocodiles (Crocodylus siamensis) with conjunctivitis/pharyngitis lesions were admitted at the Veterinary Aquatic Animal Research Health Care Unit, Faculty of Veterinary Science, Mahidol University. All crocodiles did not respond well to antibiotics or supportive treatments and died. This study aimed to detect and identify the causative agents associated with conjunctivitis/pharyngitis and fatal outcomes in juvenile farmed Siamese crocodiles. MATERIALS AND METHODS: A total of 138 pharyngeal and conjunctival swabs and conjunctival scrapes were collected from live crocodiles. All swab and scrape samples were DNA-extracted and amplified by polymerase chain reaction (PCR) using Chlamydiaceae- and herpesvirus-specific primers. Tissue samples (brain, lung, liver, heart, spleen, and intestine) were collected from two representative postmortem animals. All tissue samples were processed for molecular and pathological analyses. RESULTS: PCR examinations identified chlamydial and herpesvirus DNA in 92% (126/138) and 100% (138/138), respectively, of the tested swab and scrape samples. Of those positive samples, 79% (26/33), 67% (4/6), and 98% (97/99) of the pharyngeal swabs, conjunctival swabs, and conjunctival scrapes, respectively, were positive for both chlamydial and herpesvirus DNA. Histopathological examination indicated necrosis and mononuclear cell infiltration in the liver, kidney, and intestine of the affected animals. The intracytoplasmic accumulation of Chlamydia was randomly observed in the examined tissue sample. Moreover, the presence of chlamydial and herpesvirus DNA was also detected in the tissue samples, including the heart, intestine, brain, lung, liver, and spleen, of the affected animals by PCR. Phylogenetic analyses revealed that Chlamydia spp. detected in the juvenile Siamese crocodiles was notably different from other known species in the Chlamydia genus, while the herpesvirus detected in the crocodiles was closely related to crocodyline herpesvirus 1. CONCLUSION: Based on histopathological and molecular examinations, this report provided the first evidence of coinfection of Chlamydia spp. and crocodyline herpesvirus 1 in juvenile Siamese crocodiles in Thailand.

Epizootic reptilian ferlavirus infection in individual and multiple snake colonies with additional evidence of the virus in the male genital tract.

Reptilian ferlavirus, a pathogen of serious concern in snakes, has been reported in Western countries, but little is known about its prevalence in Thailand, where many snake breeding farms are located. In this study, we investigated the reptilian ferlavirus via swab samples derived from 49 diseased snakes and 77 healthy snakes as well as tissue samples taken from nine dead snakes from five independent snake farms. Using molecular detection, we found the ferlavirus in 8.16% of diseased snakes, but not in healthy snakes. Out of nine farmed snakes, eight snakes derived from four farms were found to be positive. Four complete genome sequences of the ferlavirus were successfully obtained and phylogenetically clustered to the highly pathogenic ferlavirus. Tissue tropism of the ferlavirus was identified in various epithelial cell types using the in situ hybridization technique. Interestingly, the hybridization signals were strongly labeled in the male genital tract. Transmission electron microscopy was used to support the ferlaviral localization in the male genital tract. This study provides the first evidence of ferlavirus localization in the male genital tract and contributes to the knowledge about ferlavirus epidemiology, indicating that there needs to be further awareness and elucidation regarding vertical transmission of reptilian ferlavirus.

Canine bocavirus-2 infection and its possible association with encephalopathy in domestic dogs.

Canine bocaviruses (CBoVs) have been recognized as pathogens associated with intestinal diseases. Hematogenous spreading caused by CBoV has been documented and may potentiate the virus entry across the blood-brain barrier to initiate a brain infection. This study focused attention on CBoV detection in cases of encepahlopathy and attempted to determine its viral localization. A total of 107 dog brains that histologically exhibited encephalopathy (ED) were investigated for the presence of CBoVs using polymerase chain reaction (PCR). Thirty-three histologically normal brain samples from dogs were used as a control group (CD). CBoV-2 was detected in 15 ED dogs (14.02%) but not in CD dogs (p = 0.02), while no CBoV-1 and -3 were detected. Among the CBoV-2 positive dogs, brain histological changes were characterized by nonsuppurative encephalitis, with inclusion body-like materials in some brains. In situ hybridization (ISH) and transmission electron microscopy (TEM) confirmed the presence of CBoV-2 viral particles in glial cells, supporting neurotropism of this virus. ISH signals were also detected in the intestines, lymphoid organs, and the heart, suggesting both enteral and parenteral infections of this virus. Whole genome characterization and evolutionary analysis revealed genetic diversity of CBoV-2 sequences and it was varying among the different countries where the virus was detected. This study points to a possible association of CBoV-2 with encephalopathy in dogs. It also highlights the genetic diversity and cellular tropism of this virus.