Immunogenicity in Aujeszky's disease virus structural glycoprotein gVI (gp50) in swine.

Aujeszky's disease virus (ADV) envelope glycoprotein gVI (gp50) was purified from virus-infected Vero cells by ion-exchange and immunoaffinity chromatography and its usefulness as a subunit vaccine was evaluated in active and passive immunization studies. Four-week-old piglets were immunized intramuscularly (IM) with purified gVI twice two weeks apart and challenged intranasally (IN) 10 days after the second immunization with 30 LD50 (10(8)PFU) of a virulent strain of ADV. Pigs, vaccinated with 100 micrograms of purified gVI, produced virus neutralizing antibodies and did not develop clinical signs after challenge exposure. The challenge virus was not isolated from nasal swabs and tonsils of gVI-vaccinated pigs, whereas non-vaccinated control pigs developed illness after challenge exposure with the same virulent ADV strain which was later recovered from their nasal swabs and tonsils. Pregnant sows vaccinated twice with purified gVI (IM) at a three week interval produced virus neutralizing antibodies in colostrum. Four-day-old sucking piglets born of vaccinated sows were passively protected by colostral antibodies against intranasal challenge with a lethal dose of virulent ADV. Sera from gVI-vaccinated pigs were distinguished from experimentally infected swine sera by their differential reactivity in enzyme-linked immunosorbent assay (ELISA) using four major viral glycoproteins (excluding gVI) as antigen purified by the use of lentil-lectin.     

Identification of Equine Subclinical Lameness Induced by Pressure to the Sole of Fore- or Hindlimb

Lameness has been investigated in past studies with kinematic analyses, and the features of lameness have been qualitatively and quantitatively analyzed. The output was, however, limited to visible lameness that was scored by experienced clinicians. Subclinical supporting lameness that was induced by subtle pressure to the sole of limb, but that could not be detected by visual check, has yet to be extensively analyzed. To find specific kinematic parameters that were influenced by such subclinical lameness of the fore- or hindlimb, we produced subclinical, subtle and mild lameness in five sound horses by applying slight pressure to the sole. Trot on a treadmill was recorded by a high-speed camera. Symmetric properties of acceleration of the head and the tuber sacrale were disturbed in mild fore- and hindlimb lameness, respectively. In subclinical forelimb lameness, no obvious changes in the symmetric properties of the head, the withers, or the tuber sacrale were observed; however, the vertical lift-off acceleration of the treated forelimb was decreased. In the case of subclinical hindlimb lameness, the lift-off points of both the treated and sound hindlimb shifted posteriad. These findings may contribute to further investigations of subclinical lameness aiming to establish new procedures for early detection of subclinical musculoskeletal disease, which would enable more timely treatment.     

Occurrence and molecular characterization of strobilurin resistance in cucumber powdery mildew and downy mildew

ABSTRACT Between 1998 and 1999, control failure of powdery mildew (Podosphaera fusca) and downy mildew (Pseudoperonospora cubensis) by the strobilurin fungicides azoxystrobin and kresoxim-methyl was observed in cucumber-growing areas of Japan. Results from inoculation tests carried out on intact cucumber plants and leaf disks clearly showed the distribution of pathogen isolates highly resistant to azoxystrobin and kresoximmethyl. Fragments of the fungicide-targeted mitochondrial cytochrome b gene were polymerase chain reaction amplified from total pathogen DNA and their sequences analyzed to elucidate the molecular mechanism of resistance. A single point mutation (GGT to GCT) in the cytochrome b gene, resulting in substitution of glycine by alanine at position 143, was found in resistant isolates of downy mildew. This substitution in cytochrome b seemed to result in high resistance to strobilurins in this pathogen. The same mutation was found in some but not all resistant isolates of powdery mildew. This study suggests that a mutation at position 143 in the target-encoding gene, resulting in an amino acid substitution, was probably a major cause of the rapid development of high strobilurin resistance in these two pathogens.     

Brain abscess in a Japanese black calf: utility of computed tomography (CT)

Computed tomography (CT) was used for diagnosis of brain abscess in a 6-month-old, Japanese black calf presented with neurological dysfunction, compulsive circling and vision disturbance. CT images showed asymmetric lateral ventricles, and presence of intra-cranial multiple low absorption lesions surrounded by capsule suggestive of abscess in the right cerebral hemisphere. Postmortem examination revealed marked swelling of right cerebral hemisphere and olfactory bulb. Multilocular large abscess containing creamy pus was found to occupy most area of periventricular and lateral ventricle. Fusobacterium necrophrum was isolated from the abscess contents as the causative agent. These results demonstrate that CT is useful tool for tentative diagnosis of bovine brain abscess.     

Effect of suckling on the reproductive performance and metabolic status of obese Japanese black cattle during the early postpartum period

The aim of our study was to investigate the effects of suckling on reproductive performance and metabolic status of obese (mean body condition score of more than 4.0 on a scale of 1-5) maternal Japanese Black cows during early postpartum period. We used 7 postpartum Japanese Black cattle. Four cows were suckled ad libitum (suckled) until completion of their first artificial insemination (AI), while 3 cows were not suckled at all because they were separated from their calves immediately after parturition (non-suckled). Body weight and plasma concentrations of metabolites and hormones were measured from wk 1 to 9 postpartum. Ovarian activity was detected using plasma progesterone concentration, and all cows received their first AI after application of the Ovsynch protocol at approximately 4 months postpartum. Although body weights of non-suckled cows increased during experimental period (P<0.05), those of suckled cows remained unchanged. Plasma concentrations of glucose of non-suckled cows were higher at wk 2 postpartum (P<0.05) and their levels of non-esterified fatty acid tended to be lower at wk 1 and 2 postpartum compared with suckled cows (P<0.1); however, these differences between groups were not observed with progression of postpartum period. In addition, plasma insulin concentrations of non-suckled cows were higher than those of suckled cows during experimental period (P<0.05). During sampling period (wk 0 to 9 postpartum), onset of normal ovarian cycle was observed in all non-suckled and 2 of 4 suckled cows, and it was delayed in other 2 suckled cows compared with non-suckled cows; however, 3 suckled cows conceived at the first AI after application of the Ovsynch protocol; none of non-suckled cows conceived at this time. Overall, we suggest that suckling seems to reduce increase of body weight after parturition, although it does not improve obesity, and influences conception despite delay in resumption of normal ovarian cyclicity in obese Japanese Black cows.     

A survey of amoebic infections and differentiation of an Entamoeba histolytica-like variant (JSK2004) in nonhuman primates by a multiplex polymerase chain reaction

A pathogenic Entamoeba histolytica-like variant (JSK2004 strain) with genetic variations and a novel isoenzyme pattern isolated from a De Brazza's guenon in a Tokyo zoo in Japan has previously been documented. In this study, a multiplex polymerase chain reaction (PCR) assay that could distinguish the JSK2004-type E. histolytica-like variant (JSK04-Eh-V) from E. histolytica and Entamoeba dispar using three newly designed primer sets for amplifying each specific DNA fragment from their small-subunit ribosomal RNA genes was developed and established. Forty-seven primates (11 species) from the zoo were surveyed by multiplex PCR to assess the prevalence of JSK04-Eh-V infection, which was recognized in six individuals of four species, including an Abyssinian colobus monkey, a De Brazza's guenon (including the individual from whom JSK2004 was isolated), a white-faced saki, and a Geoffroy's spider monkey. In addition, the autopsied individuals of an Abyssinian colobus and Geoffroy's spider monkey that died of amoebic liver abscess were also evaluated. DNA samples were also analyzed for specific genotypes based on the nucleotide sequencing of two protein-coding (chitinase and serine-rich E. histolytica protein) genes and the protein-noncoding locus 1-2 that was used for fingerprinting of the E. histolytica strain. These studies indicated that the E. histolytica-like variant infection in this zoo was caused by the same type (i.e., JSK04-Eh-V). An axenic culture medium (yeast extract-iron-maltose-dihydroxyacetone-serum) was developed based on the yeast extract-iron-gluconic acid-dihydroxyacetone-serum medium, which is designed for axenic culture of E. dispar. This new medium could be used for axenically culturing E. histolytica, JSK04-Eh-V, and E. dispar in a single medium.     

Relationship between plasma vitamin C and serum diagnostic biochemical markers in lactating cows

We investigated the relationship between plasma vitamin C concentration and serum levels of some diagnostic biochemical markers in 118 lactating Holstein cows. Blood sample was collected once from each cow and we measured the plasma vitamin C concentration and the serum levels of glucose, beta-hydroxybutyrate, free fatty acids, triacylglycerol, total cholesterol, albumin, total bilirubin, alkaline phosphatase, aspartate aminotransferase and gamma-glutamyltransferase. The regression of plasma vitamin C with each serum diagnostic biochemical marker indicated that the vitamin C concentration significantly decreased as glucose, alkaline phosphatase or aspartate aminotransferase level increased and as total cholesterol or albumin concentration decreased. Furthermore, the plasma vitamin C concentration was significantly lower in the cows showing that each of these marker levels was out of its reference interval than in the cows showing that the marker level was within its reference interval. The significant correlations were observed among total cholesterol, albumin, alkaline phosphatase and aspartate aminotransferase levels, to which the glucose concentration was not related. These results showed that the plasma vitamin C concentration was low in the cows that had concurrently low levels of total cholesterol and albumin, and high levels of alkaline phosphatase and aspartate aminotransferase. Therefore, a hepatic malfunction possibly decreases plasma vitamin C concentration through suppressing vitamin C production. On the other hand, the high level of glucose possibly decreases plasma vitamin C concentration through suppressing vitamin C recycling.     

Factors Affecting the Incidence of Postpartum Fever in Heavy Draft Mares

Postpartum metritis is a common problem in many animal species. In equine medicine, sequelae of postpartum metritis vary from delay in uterine involution to development of systemic acute metritis (SAM), toxemia, and laminitis. Heavy draft mares potentially have higher risk of suffering from SAM than light breed mares. Postpartum fever (PF) mostly appears as a sign of SAM. The purpose of this study is to analyze the factors affecting the incidence of PF in 158 foalings from 62 heavy draft mares by multiple logistic regressions. The objective variable was the incidence of PF, and the explanatory variables were year foaled, month foaled, age of mare, breed of mare (crossbred heavy draft horse vs. Percheron), gestation length, foaling difficulty (easy delivery vs. dystocia), retained fetal membranes, stillbirth, and sex of offspring. Twenty-four out of 158 mares were diagnosed with PF. Stepwise regression analysis showed that breed of dams and foaling difficulty were significant risk factors for PF. Percheron mares had higher risk than crossbred mares (odds ratio: 3.4). Dystocia had higher risk than easy delivery (odds ratio: 3.3). Percheron mares had higher incidence of PF than crossbred mares even in the cases of easy delivery. Risks for damage and contamination of birth canal will be increased especially if the fetal delivery needs assistance. The results of this study suggest that it is necessary to consider the foaling difficulty and the breed of dams for earlier detection of PF in peripartum heavy draft mares.