An etiological investigation of domestic cats with conjunctivitis and upper respiratory tract disease in Japan

Chlamydophila felis (C. felis), feline herpesvirus-1 (FHV-1) and feline calicivirus (FCV) were detected in 39 (59.1%), 11 (16.7%) and 14 (21.2%) cats respectively, from 66 domestic cats presented with conjunctivitis and upper respiratory tract disease (URTD) in 9 prefectures of Japan. Dual and multiple infections were found in 7 (10.6%) cats with both C. felis and FHV-1, 10 (15.2%) cats with both C. felis and FCV, and 1 (1.5%) cat with all three agents. C. felis was isolated from 11 (28.2%) of 39 PCR positive cats. Antigenic difference was found in a 96 kDa protein of our isolates and Fe/145 strain isolated in USA. In conclusion, C. felis is the most common agent of feline conjunctivitis and URTD, and the coinfection with C. felis, FHV-1 and FCV are also common in cats in Japan.     

Porencephaly in a cynomolgus monkey ( macaca fascicularis )

Porencephaly was observed in a female cynomolgus monkey (Macaca fascicularis) aged 5 years and 7 months. The cerebral hemisphere exhibited diffuse brownish excavation with partial defects of the full thickness of the hemispheric wall, and it constituted open channels between the lateral ventricular system and arachnoid space. In addition, the bilateral occipital lobe was slightly atrophied. Histopathologically, fibrous gliosis was spread out around the excavation area and its periphery. In the roof tissue over the cavity, small round cells were arranged in the laminae. They seemed to be neural or glial precursor cells because they were positive for Musashi 1 and negative for NeuN and GFAP. In the area of fibrous gliosis, hemosiderin or lipofuscin were deposited in the macrophages, and activated astroglias were observed extensively around the excavation area.     

Molecular epidemiology of avian influenza viruses circulating among healthy poultry flocks in farms in northern Vietnam

Repeated epizootics of highly pathogenic avian influenza (HPAI) virus subtype H5N1 were reported from 2003 to 2005 among poultry in Vietnam. More than 200 million birds were killed to control the spread of the disease. Human cases of H5N1 infection have been sporadically reported in an area where repeated H5N1 outbreaks among birds had occurred. Subtype H5N1 strains are established as endemic among poultry in Vietnam, however, insights into how avian influenza viruses including the H5N1 subtype are maintained in endemic areas is not clear. In order to determine the prevalence of different avian influenza viruses (AIVs), including H5N1 circulating among poultry in northern Vietnam, surveillance was conducted during the years 2006-2009. A subtype H5N1 strain was isolated from an apparently healthy duck reared on a farm in northern Vietnam in 2008 and was identified as an HPAI. Although only one H5N1 virus was isolated, it supports the view that healthy domestic ducks play a pivotal role in maintaining and transmitting H5N1 viruses which cause disease outbreaks in northern Vietnam. In addition, a total of 26 AIVs with low pathogenicity were isolated from poultry and phylogenetic analysis of all the eight gene segments revealed their diverse genetical backgrounds, implying that reassortments have occurred frequently among strains in northern Vietnam. It is, therefore, important to monitor the prevalence of influenza viruses among healthy poultry between epidemics in an area where AIVs are endemic.     

Concentrations of ketone body and antidiuretic hormone in cerebrospinal fluid in response to the intra‐ruminal administration of butyrate in suckling calves

The aim of the present study was to elucidate the mechanism by which ketone bodies increase antidiuretic hormone (ADH) secretion. Four male Holstein calves (5 weeks of age) were utilized. Four levels of butyrate (0 g, 11 g, 22 g and 44 g) were administrated intra‐ruminally in a 4 × 4 Latin square design and cerebrospinal fluid (CSF, six‐position lumbar puncture), blood plasma and urine were collected. The concentration of total plasma and CSF protein was 5.5–5.6 g/dL and 27.5–28.3 mg/dL, respectively. CSF concentrations of a specific ketone body, 3‐hydroxybutyric acid, were significantly higher in the 22 g and 44 g butyrate groups than in the control group. CSF concentrations of ADH in the 11 g and 44 g butyrate groups were significantly higher than in the control group. Plasma concentration of 3‐hydroxybutyric acid was increased by intraruminal administration of butyrate within 15 min in a dose‐dependent manner, and it was higher in the 22 g and 44 g butyrate group than in the control group from 15 min to 4 h. With the exception of the 11 g butyrate group, plasma concentrations of ADH also increased in response to butyrate treatment, and it was higher in the 44 g butyrate group than in the 22 g butyrate group from 15 min to 1.5 h. The duration of the elevated plasma concentrations of ADH was shorter than that of the plasma concentration of 3‐hydroxybutyric acid. The relationship between the plasma concentrations of ADH and 3‐hydroxybutyric acid was statistically significant but the correlation between the two concentrations was not high. Butyrate treatment elevated the plasma concentration of ADH and also resulted in reduced urine volume and increased urine osmolality. Haematocrit (Ht) values, and the osmolality of CSF and plasma were not different among the groups. Our results suggested that the increased ADH secretion observed in suckling calves fed dry feeds was caused by butyrate‐derived ketone body that crossed the blood‐brain barrier rapidly.     

Frequencies of bovine PrP gene polymorphisms in Holstein and Japanese Black bulls in Japan

We screened for Japanese Black and Holstein bull sire samples to detect single nucleotide polymorphisms (SNPs) involving animo‐acid substitutions in the bovine prion gene in the entire coding region of the PRNP gene. Although three silent SNPs were found, we could not detect any SNP with animo‐acid substitution. We also examined the polymorphism of the octapeptide repeat number in these samples. There was no homozygous bull with repeat number 5. The frequency of heterozygous (6/5) bulls was 8% in the Japanese Black bull and 4% in the Holstein bull, respectively. The bull samples used in this study contain popular elite sires, so it appears that the polymorphisms of prion protein (PrP) are rather difficult to find in these two breeds in Japan, except for polymorphism of the octapeptide repeat number.     

Evaluation of Salmonella enterica serovar Typhimurium and Choleraesuis slyA mutant strains for use in live attenuated oral vaccines

SlyA protein plays a key role in virulence in Salmonella enterica. In this study, we evaluated the ability of the slyA mutant strain of S. enterica serovar Choleraesuis (S. choleraesuis) to protect against swine salmonellosis. Using a murine model infected with S. enterica serovar Typhimurium (S. typhimurium), we showed that the Salmonella strain with a deletion of slyA could be used as a highly immunogenic, effective and safe vaccine in mice. Based on these data, a slyA mutant of S. enterica serovar Choleraesuis strain RF-1 was constructed, and the ability of this mutant to protect immunized pigs from S. choleraesuis infection was examined. As with the S. typhimurium slyA mutant, immunization of pigs with the S. choleraesuis slyA mutant strain provided significant protection against subsequent challenge by the wild-type RF-1. These results demonstrate that SlyA is a potential target in the development of a novel live attenuated vaccine against S. enterica.     

The characterization of low pathogenic avian influenza viruses isolated from wild birds in northern Vietnam from 2006 to 2009

Due to concerns that wild birds could possibly spread H5N1 viruses, surveillance was conducted to monitor the types of avian influenza viruses circulating among the wild birds migrating to or inhabiting in northern Vietnam from 2006 to 2009. An H5N2 virus isolated from a Eurasian woodcock had a close phylogenetic relationship to H5 viruses recently isolated in South Korea and Japan, suggesting that H5N2 has been shared between Vietnam, South Korea, and Japan. An H9N2 virus isolated from a Chinese Hwamei was closely related to two H9N2 viruses that were isolated from humans in Hong Kong in 2009, suggesting that an H9N2 strain relevant to the human isolates had been transmitted to and maintained among the wild bird population in Vietnam and South China. The results support the idea that wild bird species play a significant role in the spread and maintenance of avian influenza and that this also occurs in Vietnam.     

Incidence of Salmonella infection in healthy dogs in Gifu Prefecture,Japan

A total of 1,013 feces samples and 8 mesenteric lymphonodus samples obtained from apparently healthy dogs were examined for the incidence of salmonella infection. One strain of S. typhimurium (ST) was isolated from feces of one dog, and S. enteritidis (SE) was isolated from the mesenteric lymphonodus of one dog. Sera obtained from 330 apparently healthy dogs were examined for Salmonella antibodies using an ELISA with heated whole cells of SE and ST. Fifty-one of the 330 serum samples were considered to be positive for salmonella antibodies, including 12 which were SE-positive and 39 which were ST-positive. These results indicate that dogs cause possible environmental problems as Salmonella carriers.