Abnormal prion protein in ectopic lymphoid tissue in a kidney of an asymptomatic white-tailed deer experimentally inoculated with the agent of chronic wasting disease

Chronic wasting disease (CWD), a transmissible spongiform encephalopathy (TSE) of deer and elk, is one of a group of fatal, neurologic diseases that affect several mammalian species, including human beings. Infection by the causative agent induces accumulations of an abnormal form of prion protein (PrPres) in nervous and lymphoid tissues. This report documents the presence of PrPres within ectopic lymphoid follicles in a kidney of a white-tailed deer that had been experimentally inoculated by the intracerebral route with CWD 10 months previously. The deer was nonclinical, but spongiform lesions characteristic of TSE were detected in tissues of the central nervous system (CNS) and PrPres was seen in CNS and in lymphoid tissues by immunohistochemistry. The demonstration of PrPres in lymphoid tissue in the kidney of this deer corroborates a recently published finding of PrPres in lymphoid follicles of organs other than CNS and lymphoid tissues in laboratory animals with TSE (scrapie).     

The bacteriology and serology of ewes inoculated with viable Brucella ovis organisms

A series of 10 farm trials was conducted in which the lambing performance of ewes immunised against polyandroalbumin was compared with that of untreated ewes in the same flock. The trials show that polyandroalbumin treatment is a reliable method of increasing lambing and tailing percentages in New Zealand flocks. An average of 39 extra lambs born per 100 ewes tupped was achieved on farms where ewes were given two treatments about four weeks apart and rams were introduced 18–26 days after the second dose. On farms where rams were introduced less than 12 days after this booster injection an average of 19 extra lambs born per 100 ewes tupped resulted.

On farms where rams were introduced at 18–26 days post booster injection an average of 35 extra lambs were tailed for every 100 ewes tupped.

The response for immunization increased in direct relation to the liveweight of the ewes at tupping.     

Sheep experimentally infected with Sarcocystis from dogs. II. Abortion and disease in ewes.

This is the first study of Sarcocystis-induced abortion in sheep. Eleven pregnant ewes were experimentally inoculated with 50,000, 100,000, or 500,000 Sarcocystis ovicanis sporocytis from dogs. Eight ewes either aborted, died, or became moribund before term; they produced 15 fetuses, 11 of normal appearance and 4 necrotic. No evidence of intrauterine transmission was obtained. All infected ewes became anemic, inappetent, and lost weight. Ewes inoculated with the greatest numbers of sporocysts exhibited the most striking signs of acute illness. At necropsy of acutely ill ewes the heart was the most severely affected organ, appearing nearly black as a result of hemorrhagic pancarditis. Less hemorrhage was seen in the kidney, liver, spleen, and skeletal muscles. Microscopically, schizonts were found in capillary endothelial cells of most organs 24 to 33 days after inoculation. Ewes surviving the acute illness appeared generally unthrifty and exhibited the additional signs of wool breaking, and nervous disturbances. At postmortem, the heart and kidneys of these ewes were moderately hemorrhagic, and the adrenal glands and mesenteric lymph nodes were enlarged. Microscopically, sarcocysts were found in the heart, diaphragm esophagus, tongue, skeletal and eye muscles, cerebellum, and cerebrum.     

Evaluation of biochemical evidence of congenital nutritional myopathy in two-week prepartum fetuses from selenium-deficient ewes

Muscle damage attributable to selenium (Se)/vitamin E deficiencies is known to develop at birth or later in lambs. The purpose of this study was to determine whether and when muscle damage develops in utero. Thirty pregnant ewes maintained on Se-deficient forages from birth were allotted to 3 equal groups. Half of each group was given a single IM injection of 0.056 mg of Se/kg of body weight, 1 month before parturition. At 3 weeks before parturition, cesarean section-derived fetuses from Se-deficient ewes did not have evidence of muscle damage. At 2 weeks before parturition, fetuses from Se-deficient ewes had biochemical evidence of congenital nutritional myopathy, as evidenced by low blood Se concentration (P less than 0.05) and by increased plasma creatinine kinase (P less than 0.001) and lactate dehydrogenase (P less than 0.01) activities, compared with fetuses from Se-treated ewes. Thus, for optimal protection of fetuses and newborn lambs in Se-deficient areas, Se should be administered to ewes at least 1 month before parturition.     

Age-related lesions in laboratory-confined raccoons (Procyon lotor) inoculated with the agent of chronic wasting disease of mule deer.

This communication documents age-associated pathologic changes and final observations on experimental transmission of chronic wasting disease (CWD) by the intracerebral route to raccoons (Procyon lotor). Four kits were inoculated intracerebrally with a brain suspension from mule deer with CWD. Two uninoculated kits served as controls. One CWD-inoculated raccoon was humanely killed at 38 months after inoculation, and 1 control animal died at 68 months after inoculation. Both animals had lesions that were unrelated to transmissible spongiform encephalopathy. Six years after inoculation, none of the 3 remaining CWD-inoculated raccoons had shown clinical signs of neurologic disorder, and the experiment was terminated. Spongiform encephalopathy was not observed by light microscopy, and the presence of abnormal prion protein (PrP(d)) was not detected by either immunohistochemistry or Western blot techniques. Age-related lesions observed in these raccoons included islet-cell pancreatic amyloidosis (5/6), cystic endometrial hyperplasia (3/4), cerebrovascular mineralization (5/6), neuroaxonal degeneration (3/6), transitional-cell adenoma of the urinary bladder (1/6), and myocardial inclusions (4/6). The latter 2 pathologic conditions were not previously reported in raccoons.     

The early pathogenesis in chicken inoculated with non-pathogenic serotype 2 Marek's disease virus.

A newly cloned serotype 2 Marek's disease virus (MDV), strain ML-6, was inoculated via the nasal cavity in specific-pathogen-free chicks to examine early virus replication and the expression of Marek's disease (MD)-related antigens. Following inoculation, viral intracellular antigens (VIAs) were detected in lymphoid organs (bursas and spleens) between 5 and 14 days post inoculation (PI), in feather follicles between 14 and 30 days PI, and in lungs at 3 days PI by the immunohistopathological staining of avidin-biotin-peroxidase complex method. But, very few VIAs were expressed in the thymuses between 5 and 14 days PI. However, MD tumor-associated surface antigens were not detected in any organs. Viruses were isolated from separated spleen cells at 14 and 30 days PI. Fluorescent antibodies of convalescent sera were also detected after 10 days PI. As most of the VIAs were detectable in B-cells in bursas and spleens. B-cells were considered to be the main first target cells for the serotype 2 MDV infection.     

Border disease in sheep caused by transmission of virus from cattle persistently infected with bovine virus diarrhoea virus.

Two outbreaks of border disease occurred on farms with sheep flocks and breeding cattle. The infection of the pregnant sheep was probably caused by transmission of virus from calves persistently infected with non-cytopathic bovine virus diarrhoea virus (BVDV) which were kept in close confinement with the ewes during mid-pregnancy. Border disease was also induced experimentally in eight lambs by exposing their dams at 38 to 78 days of gestation to a heifer persistently infected with BVDV. Both the natural and the experimental infections were characterised by typical signs such as 'hairy-shaker' lambs and high lamb mortality. The diagnosis was confirmed by virus isolations from live-born lambs, seroconversion and pathology. The study supports the assertion that cattle persistently infected with BVDV and in close contact with pregnant sheep, are an important source of strains of virus capable of causing border disease.     

Pathogenesis in call ducks inoculated intranasally with H5N1 highly pathogenic avian influenza virus and transmission by oral inoculation of infective feathers from an infected call duck

To evaluate the possibility of virus transmission through feathers of call ducks, we performed two experiments, intranasal infection study and transmission study, using the Japanese H5N1 highly pathogenic avian influenza virus (HPAIV) A/chicken/Yamaguchi/7/2004 (Ck/Yama/7/04). In Experiment 1, 1-day-old, 2-wk-old, and 4-wk-old birds were inoculated intranasally with Ck/Yama/7/04. Birds in all age groups exhibited necrosis and/or viral antigens in the feather epithelium. Nonpurulent encephalitis and focal necrosis of the pancreas and heart also were common to inoculated birds. In Experiment 2, nine 2-wk-old birds that were orally inoculated with feathers of an infected call duck exhibited the nonpurulent encephalitis, necrosis of the feather epithelium, and focal necrosis of the pancreas and heart, accompanied by viral antigens. These lesions were similar to those in intranasal infection. Some birds were positive for the virus isolation from cloacal swabs and hemagglutination inhibition antibody. The infection was confirmed in seven of nine birds. This study confirmed that the Japanese HPAIV can replicate in the feather epithelium, causing necrosis in call ducks through the natural infection route. It also suggests that feathers of call ducks infected with Ck/Yama/7/04 can be a potential source of infection for unaffected birds in nature.     

Biotypes and sensitivity screening Yersinia enterocolitica as an infective agent in man and swine in Nigeria.

Diarrhoeic faecal samples from 210 humans and 192 swine were screened for Yersinia enterocolitica in 1990. Ten and 8 Y. enterocolitica strains were isolated from pig and man, respectively. The isolates were found to belong to Wauter's biotypes 1, 2, 3 and 4. Biotype 2 was isolated mainly from human stool samples. Biotype 3 was found only in swine while biotypes 1 and 4 were isolated from both man and swine. All the 18 strains showed varying degrees of sensitivity to antibiotics used in this investigation. The organisms were consistent in their resistance to ampicillin and penicillin.     

Clinical and laboratorial findings in pregnant ewes and their progeny infected with Border disease virus (BDV-4 genotype)

To evaluate the pathogenicity of local isolates of ovine pestiviruses (BDV-4 genotype), 13 virus- and antibody-negative, artificially inseminated pregnant ewes were challenged on days 108 (5 ewes), 76 (5 ewes) and 55 of pregnancy (3 ewes) with 2 ml of ovine pestivirus containing 10⁶ TCID₅₀. Viraemia was detected by RT-PCR from 2 to 15 days pi in most ewes. No abortion due to the infection was observed but the number of stillbirths was high (32%), and bodyweight at lambing was significantly reduced compared to the experimental flock of origin used as control. Clinical symptoms in live lambs consisted on tremors, gait anomalies and inability to stand unaided. Skeletal abnormalities (brachygnathia, prognathia, arthrogryposis) were present in 44% of the lambs. Only 20% of the lambs were clinically normal. RT-PCR was a very sensitive technique compared to antigen ELISA in detecting viral presence in experimentally infected ewes and their progeny.