SUMMARY. Rodents serve as amplifiers of Salmonella infections in poultry flocks and can serve as ... more SUMMARY. Rodents serve as amplifiers of Salmonella infections in poultry flocks and can serve as a source of Salmonella contamination in the environment even after thorough cleaning and disinfection. This study aims to determine the dynamics of Salmonella occurrence in rodents and its relation to Salmonella contamination in the layer farm environment, including air dusts and eggs. From 2008 to 2017, roof rats (Rattus rattus), environmental swabs, air dusts, and eggs were collected from an intensive commercial layer farm in East Japan and were tested for Salmonella spp. using standard procedures. In roof rat samples, the Salmonella isolation rate was reached at 10% (95% confidence interval [CI] 8.1–21.9) in which Salmonella Corvallis, Salmonella Infantis, Salmonella Potsdam, and Salmonella Mbandaka were the frequent isolates from the cecal portion of the intestines. On the other hand, the prevalence rate of Salmonella in environmental swabs was at 5.1% (95% CI 2.2–7.4) while air dusts were at 0.9% (95% CI 0.2–1.8). It was observed that the prevalence of predominant Salmonella serotypes shifted over time; in roof rats, it was noted that Salmonella Potsdam gradually replaced Salmonella Infantis. In environmental swabs and eggs, Salmonella Corvallis and Salmonella Potsdam increased significantly while Salmonella Infantis became less frequent. In air dusts, Salmonella Corvallis was observed to decrease and Salmonella Potsdam became more common. Based on our findings, the role of roof rats in the epidemiology of Salmonella in layer farms was expanded from being a reservoir and an amplifier host into a shifting vessel of the most predominant serotypes.
Eimeria tenella is an intracellular apicomplexan parasite, which infects cecal epithelial cells f... more Eimeria tenella is an intracellular apicomplexan parasite, which infects cecal epithelial cells from chickens and causes hemorrhagic diarrhea and eventual death. We have previously reported the comparative RNA sequence analysis of the E. tenella sporozoite stage between virulent and precocious strains and showed that the expression of several genes involved in mitochondrial electron transport chain (ETC), such as type II NADH dehydrogenase (NDH-2), complex II (succinate:quinone oxidoreductase), malate:quinone oxidoreductase (MQO), and glycerol-3-phosphate dehydrogenase (G3PDH), were upregulated in virulent strain. To study E. tenella mitochondrial ETC in detail, we developed a reproducible method for preparation of mitochondria-rich fraction from sporozoites, which maintained high specific activities of dehydrogenases, such as NDH-2 followed by G3PDH, MQO, complex II, and dihydroorotate dehydrogenase (DHODH). Of particular importance, we showed that E. tenella sporozoite mitochondri...
Peripheral blood samples from dogs infected with Babesia gibsoni were analyzed by flow cytometry ... more Peripheral blood samples from dogs infected with Babesia gibsoni were analyzed by flow cytometry for parasitized erythrocytes after staining with hydroethidine. Cells identified as positive by flow cytometry were erythrocytes infected with B. gibsoni. Analysis of 26 samples by flow cytometry for % parasitemia revealed a correlation coefficient of 0.97 in comparison to the conventional method of light microscopy.
Bovine intranuclear coccidiosis is caused by the protozoans Eimeria alabamensis and Cyclospora sp... more Bovine intranuclear coccidiosis is caused by the protozoans Eimeria alabamensis and Cyclospora spp. Here, we characterized the disease and genetically identified the causative species in Japanese black calves with chronic and refractory watery diarrhea. Histologic examinations revealed atrophy of the jejunal villi and numerous parasites in the nucleus of epithelial cells in the jejunum. Based on molecular analyses using 18S ribosomal RNA gene-specific primers that we designed, the parasites were found to be formed in the same cluster as Eimeria subspherica in the phylogenetic tree, which was separated from those of other related Eimeria spp. These results constitute the first report of E. subspherica as a cause of bovine intranuclear coccidiosis.
Entamoeba suis and Entamoeba polecki subtypes (ST) 1 and 3 have recently been implicated in disea... more Entamoeba suis and Entamoeba polecki subtypes (ST) 1 and 3 have recently been implicated in disease outbreaks in pigs. However, the distributions of these parasites in Japan and the potential sources of infection on farms still remain unclear. Here, we examined a farm of fattening/growing pigs with abnormal feces in Kagoshima Prefecture, Japan, and found the presence of parasites in the farm environment. Examination of intestinal tissues from pigs presenting with ulcerative colitis revealed a large number of trophozoites that had invaded the lesions. We identified single and mixed infections of E. suis and E. polecki ST1 and ST3 in paraffin sections or fecal samples from affected pigs. Two subtypes of Entamoeba were identified using four primer sets by PCR and sequencing. The parasites were detected in moist soil samples obtained around the drinking water source or puddles, implicating transmission of cysts via contaminated soils. Additionally, we found evidence of Entamoeba spp. an...
Raccoons (Procyon lotor) are found worldwide. They are frequently seen in crowded inner cities as... more Raccoons (Procyon lotor) are found worldwide. They are frequently seen in crowded inner cities as well as in forests or wooded areas, often living in proximity to humans and their pets. We examined sera from 100 wild raccoons in Japan for antibodies to six canine viruses with veterinary significance to assess their potential as reservoirs. We also aimed to understand the distribution of potentially infected wildlife. We found that 7% of samples were seropositive for canine distemper virus (CDV), 10% for canine parvovirus type (CPV), 2% for canine adenovirus type 1, 6% for canine adenovirus type 2, and 7% for canine coronavirus. No samples were found to be seropositive for canine parainfluenza virus. Seropositivity rates for CDV and CPV were significantly different between areas, and younger raccoons (<1 yr old) were more frequently seropositive than older raccoons. Because raccoons belong to the suborder Caniformia, similar to dogs (Canis lupus familiaris), our results suggest th...
SUMMARY. Rodents serve as amplifiers of Salmonella infections in poultry flocks and can serve as ... more SUMMARY. Rodents serve as amplifiers of Salmonella infections in poultry flocks and can serve as a source of Salmonella contamination in the environment even after thorough cleaning and disinfection. This study aims to determine the dynamics of Salmonella occurrence in rodents and its relation to Salmonella contamination in the layer farm environment, including air dusts and eggs. From 2008 to 2017, roof rats (Rattus rattus), environmental swabs, air dusts, and eggs were collected from an intensive commercial layer farm in East Japan and were tested for Salmonella spp. using standard procedures. In roof rat samples, the Salmonella isolation rate was reached at 10% (95% confidence interval [CI] 8.1–21.9) in which Salmonella Corvallis, Salmonella Infantis, Salmonella Potsdam, and Salmonella Mbandaka were the frequent isolates from the cecal portion of the intestines. On the other hand, the prevalence rate of Salmonella in environmental swabs was at 5.1% (95% CI 2.2–7.4) while air dusts were at 0.9% (95% CI 0.2–1.8). It was observed that the prevalence of predominant Salmonella serotypes shifted over time; in roof rats, it was noted that Salmonella Potsdam gradually replaced Salmonella Infantis. In environmental swabs and eggs, Salmonella Corvallis and Salmonella Potsdam increased significantly while Salmonella Infantis became less frequent. In air dusts, Salmonella Corvallis was observed to decrease and Salmonella Potsdam became more common. Based on our findings, the role of roof rats in the epidemiology of Salmonella in layer farms was expanded from being a reservoir and an amplifier host into a shifting vessel of the most predominant serotypes.
Eimeria tenella is an intracellular apicomplexan parasite, which infects cecal epithelial cells f... more Eimeria tenella is an intracellular apicomplexan parasite, which infects cecal epithelial cells from chickens and causes hemorrhagic diarrhea and eventual death. We have previously reported the comparative RNA sequence analysis of the E. tenella sporozoite stage between virulent and precocious strains and showed that the expression of several genes involved in mitochondrial electron transport chain (ETC), such as type II NADH dehydrogenase (NDH-2), complex II (succinate:quinone oxidoreductase), malate:quinone oxidoreductase (MQO), and glycerol-3-phosphate dehydrogenase (G3PDH), were upregulated in virulent strain. To study E. tenella mitochondrial ETC in detail, we developed a reproducible method for preparation of mitochondria-rich fraction from sporozoites, which maintained high specific activities of dehydrogenases, such as NDH-2 followed by G3PDH, MQO, complex II, and dihydroorotate dehydrogenase (DHODH). Of particular importance, we showed that E. tenella sporozoite mitochondri...
Peripheral blood samples from dogs infected with Babesia gibsoni were analyzed by flow cytometry ... more Peripheral blood samples from dogs infected with Babesia gibsoni were analyzed by flow cytometry for parasitized erythrocytes after staining with hydroethidine. Cells identified as positive by flow cytometry were erythrocytes infected with B. gibsoni. Analysis of 26 samples by flow cytometry for % parasitemia revealed a correlation coefficient of 0.97 in comparison to the conventional method of light microscopy.
Bovine intranuclear coccidiosis is caused by the protozoans Eimeria alabamensis and Cyclospora sp... more Bovine intranuclear coccidiosis is caused by the protozoans Eimeria alabamensis and Cyclospora spp. Here, we characterized the disease and genetically identified the causative species in Japanese black calves with chronic and refractory watery diarrhea. Histologic examinations revealed atrophy of the jejunal villi and numerous parasites in the nucleus of epithelial cells in the jejunum. Based on molecular analyses using 18S ribosomal RNA gene-specific primers that we designed, the parasites were found to be formed in the same cluster as Eimeria subspherica in the phylogenetic tree, which was separated from those of other related Eimeria spp. These results constitute the first report of E. subspherica as a cause of bovine intranuclear coccidiosis.
Entamoeba suis and Entamoeba polecki subtypes (ST) 1 and 3 have recently been implicated in disea... more Entamoeba suis and Entamoeba polecki subtypes (ST) 1 and 3 have recently been implicated in disease outbreaks in pigs. However, the distributions of these parasites in Japan and the potential sources of infection on farms still remain unclear. Here, we examined a farm of fattening/growing pigs with abnormal feces in Kagoshima Prefecture, Japan, and found the presence of parasites in the farm environment. Examination of intestinal tissues from pigs presenting with ulcerative colitis revealed a large number of trophozoites that had invaded the lesions. We identified single and mixed infections of E. suis and E. polecki ST1 and ST3 in paraffin sections or fecal samples from affected pigs. Two subtypes of Entamoeba were identified using four primer sets by PCR and sequencing. The parasites were detected in moist soil samples obtained around the drinking water source or puddles, implicating transmission of cysts via contaminated soils. Additionally, we found evidence of Entamoeba spp. an...
Raccoons (Procyon lotor) are found worldwide. They are frequently seen in crowded inner cities as... more Raccoons (Procyon lotor) are found worldwide. They are frequently seen in crowded inner cities as well as in forests or wooded areas, often living in proximity to humans and their pets. We examined sera from 100 wild raccoons in Japan for antibodies to six canine viruses with veterinary significance to assess their potential as reservoirs. We also aimed to understand the distribution of potentially infected wildlife. We found that 7% of samples were seropositive for canine distemper virus (CDV), 10% for canine parvovirus type (CPV), 2% for canine adenovirus type 1, 6% for canine adenovirus type 2, and 7% for canine coronavirus. No samples were found to be seropositive for canine parainfluenza virus. Seropositivity rates for CDV and CPV were significantly different between areas, and younger raccoons (<1 yr old) were more frequently seropositive than older raccoons. Because raccoons belong to the suborder Caniformia, similar to dogs (Canis lupus familiaris), our results suggest th...
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Papers by Kazumi Sasai