Effects of subclinical pregnancy toxemia on immune responses in sheep.

OBJECTIVE: To determine the effects of moderate feed restriction, single or twin pregnancy, and subclinical pregnancy toxemia (PT) on immune responses of ewes. ANIMALS: 16 Sardinian ewes. PROCEDURE: Six weeks before lambing, ewes were assigned to 1 of 2 groups (n = 8/group) matched for number of fetuses, body condition score, and plasma glucose, non-esterified fatty acids (NEFA), and beta hydroxybutyrate (BHBA) concentrations, and feed intake was restricted for 1 of the groups. Cell-mediated immunity was evaluated in vivo and in vitro. Humoral immunity was evaluated in vivo by determining production of IgG antibodies against keyhole limpet hemocyanin (KLH). RESULTS: Four ewes developed subclinical PT (plasma BHBA concentration > 0.86 mmol/L without any clinical signs of disease). Whether feed was restricted and type of pregnancy (single vs twin) did not have any significant effects on cell-mediated and humoral immune responses. Ewes with subclinical PT had significantly lower in vitro proliferation of phytohemagglutinin-stimulated peripheral blood mononuclear cells and significantly lower values for KLH-specific IgG than did healthy ewes. Plasma BHBA and NEFA concentrations were negatively correlated with in vitro proliferation of peripheral blood mononuclear cells; plasma NEFA concentration was negatively correlated with values for KLH-specific IgG. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that subclinical PT may be associated with impairments in cell-mediated and humoral immune responses in sheep.     

The ocular lesions of naturally occurring lymphocystis in fish.

Six cases of ocular lymphocystis, a virus disease, are described. Lymphocystis is generally known as a benigh, unique, giant cell disease of fishes causing nodules on the skin and fins. It has been studied extensively because of the virus-host cell relationship that results in extreme size and lack of quick cellular destruction or stimulation to neoplasia. Lymphocystis cells were found behind or in one or both eyes and were also found on the cornea or adjacent skin surfaces. A retrobulbar mass produced extreme exophthalmos. Uveal (choroid and iris) masses were present in most cases. Optic nerve involvement was also seen. It is probable that the virus reached the eye by the blood with the resulting masses forming in situ rather than by direct extension from skin lesions.     

羊妊娠毒血症的防治

羊妊娠毒血症是怀孕末期母羊由于碳水化合物和挥发性脂肪酸代谢障碍而发生的亚急性代谢病,以低血糖、酮病、虚弱和失明为主要特征.主要临床表现为精神沉郁,食欲减退,运动失调,呆滞凝视,卧地不起,甚而昏睡等.近半年来,我站门诊已治该病1 3例,其中绵羊11例,山羊2例.治愈10例,药物引产2例,死亡1例.     

Canine viral enteritis. II. Morphologic lesions in naturally occurring parvovirus infection.

The morphologic lesions associated with naturally occurring canine parvovirus infection are described. The disease is characterized by necrosis of crypt epithelium in the small intestine and of lymphoid tissue in Peyers patches, lymph nodes, spleen and thymus.     

Skeletal lesions associated with a naturally occurring poult enteritis

One-day-old poults were placed on contaminated litter on which poults previously had developed an enteric disease characterized by diarrhea, increased mortality, and stunting. These exposed birds were examined for clinical signs and pathologic changes in bone and parathyroid glands compared with controls. Intestinal and fecal samples were examined for potential pathogens. Exposed poults varied in size as early as day 8 and had significantly decreased weight gains and reduced shank lengths on days 8, 12, 16, and 21. The proximal tibial growth plate was narrowed. The mineralized hypertrophy zone was decreased in length and contained multiple non-mineralized bands on days 8, 12, 16, and 21. Metaphyseal trabeculae were reduced in amount on days 16 and 21. Parathyroid glands were hyperplastic on days 16 and 21. The bone and parathyroid gland lesions indicated that mineral homeostasis was being maintained at the expense of the skeleton during the enteric disease. A specific etiology for the enteric disease was not determined. Cryptosporidium, rotavirus, paramyxovirus, and Salmonella were identified in the exposed poults, and paramyxovirus and Salmonella were identified in the controls.     

Electroencephalogram and evoked potentials in naturally occurring scrapie in sheep

Electroencephalogram (EEG), brain stem auditory-evoked potential, and flash visual-evoked potential recordings were taken from healthy sheep and from 3 sheep with scrapie, a CNS slow virus infection. The EEG changes included semi-periodic, polyphasic, high-voltage sharp waves (bilaterally synchronous and symmetric in all channels), and a cyclic alternating pattern consisting of a high-voltage low-frequency phase, followed by a low-voltage high-frequency phase. The high-voltage phase occurred with increased arousal, and the low-voltage phase occurred with decreased arousal. Myoclonic jerks were coincident with EEG sharp waves in one sheep with scrapie. Several spontaneous focal seizures were observed. Wave-form amplitudes were greatly reduced in the brain stem auditory-evoked potential and flash visual-evoked potential; degree of reduction did not always correlate with disease severity. The EEG and evoked potential changes were seen in an exposed sheep that had not yet developed clinical signs of scrapie.     

Feather-pulp lesions in chickens with naturally occurring Marek's disease lymphomas

Feather pulps of 15-to-35-week-old chickens with Marek's disease (MD) lymphomas were examined histopathologically. Of the 64 chickens, 59 (92.2%) had lymphoproliferative (T-type) lesions in the feather pulp. The T-type feather-pulp lesion (FPL) occurred in all regions, but more frequently in the upper column of the pulp. Severe lesions were distributed throughout the feather pulp. Some of the T-type FPLs regressed to inflammatory lesions consisting of necrosis or loss of constituent cells, edema, and infiltration by small lymphocytes, heterophils, and plasma cells. The regressive T-type FPL was usually diffuse throughout the tumorous lesions, but proliferative foci were often seen concomitantly with regressive lesions. The grade and histologic picture of T-type FPLs in chickens correlated well with those of the visceral lymphomas. These findings suggest that the severity of MD lymphoma is predictable without autopsy by examining feather-pulp samples.     

Light-microscopic lesions associated with naturally occurring bursal cryptosporidiosis in chickens

Information concerning histologic significance of naturally occurring bursal Cryptosporidium sp. infection in chickens was obtained by retrospective examination of histopathology reports and clinical data from histology accessions received during 1986. Cryptosporidiosis was diagnosed in 197 bursas. In two-thirds of the accessions, more than 50% of the examined bursas were infected with Cryptosporidium sp. The histologic morphologic lesion diagnosis for Cryptosporidium sp.-infected bursas most often was marked diffuse chronic-active superficial purulent protozoal bursitis with mucosal epithelial hyperplasia. Our study clearly indicates that Cryptosporidium sp. is associated with inflammation and disturbed growth in chicken bursas. Additionally, our data indicate that Cryptosporidium sp. infection is not dependent on bursal damage attributable to other agents, including infectious bursal disease virus.     

Laboratory investigation of a naturally occurring outbreak of arthrogryposis-hydranencephaly in Texas sheep

An epizootic of abortions, weak lambs, stillbirths, and congenital arthrogryposis-hydranencephaly occurred in a sheep flock in West Texas. The outbreak began during the first week of January 1987 and continued through the third week of February 1987. Lambs born after February 1987 were not affected. A high incidence of antibodies to Cache Valley virus (Texas 7856 isolate) was demonstrated in the ewes' serum and in precolostral serum from affected lambs. No virus was isolated from tissues and body fluids of the affected lambs. The clinical, pathological, and immunological features of the epizootic were similar to those reported in Akabane virus infection in sheep. Although serological findings strongly suggest Cache Valley virus as the etiological agent of this outbreak, transmission studies are needed.     

Pregnancy toxemia in a flock of sheep

A high prevalence of metabolic disease was evident in a large flock of sheep early in the lambing season. Pregnancy toxemia and secondary hypocalcemia were diagnosed on the basis of history, physical examination findings, and results of serum biochemical analyses. To decrease costs to the owner, pooled serum samples were used to determine the metabolic health status of the flock. Ewes close to the time of lambing were found to be in severe negative energy balance, which resulted in excessive fat mobilization as well as clinical signs associated with pregnancy toxemia and hepatic lipidosis. By nutrient analysis, it was determined that the ewes had an inadequate amount of fermentable carbohydrates, which provide glucose to support the additional nutrition required during late gestation. The diet provided to sheep during late gestation should contain sufficient glucose precursors to maintain adequate glucose availability to maternal and fetal tissues. To minimize the physiologic decline in dry-matter intake during late gestation (which results in accentuation of negative energy balance), high-quality feed ingredients should be fed to ewes during this period.     

Lesions and retroviruses associated with naturally occurring ovine pulmonary carcinoma (sheep pulmonary adenomatosis)

Five sheep with ovine pulmonary carcinoma were markedly dyspneic and had sporadic coughing; two had copious watery nasal exudate. In four, lesions consisted of multifocal nodules of neoplastic cuboidal epithelial cells in acinar or papillary patterns. Electron microscopically, cells had microvilli, tight junctions, and cytoplasmic lamellar bodies typical of alveolar type II cells. One sheep had a single lung tumor of nonciliated bronchiolar epithelial cells. Vacuolated alveolar macrophages surrounded adenomatous foci. One sheep had a metastatic lesion in the caudal mediastinal lymph node. All sheep had histologic lesions of lymphoid interstitial pneumonia (LIP, ovine progressive pneumonia) consisting of peribronchiolar and interstitial lymphoid hyperplasia, and fibromuscular proliferation; all had serum precipitating antibodies to ovine lentivirus. Lung fluids or tumor homogenates contained a 26-kd peptide that crossreacted with a primate-derived type D retrovirus as detected by immunoblotting or interspecies competition radioimmunoassay. Ovine lentivirus was isolated from concentrated lung fluids or tumor tissues of four sheep tested and from tumor cell DNA of one animal transfected into ovine muscle cells. These studies document the presence of type D-related retrovirus antigen in ovine pulmonary carcinoma (OPC) in the United States and indicate that lentivirus-induced LIP is a lesion frequently associated with this disease.     

Nitric oxide metabolites in naturally occurring canine babesiosis.

Babesiosis, caused by the virulent haemoprotozoan parasite Babesia canis rossi, is an important disease of dogs in South Africa. The nitric oxide metabolites, nitrate and nitrite (collectively termed reactive nitrogen intermediates or RNIs) were measured in admission sera from dogs in a babesiosis-endemic area. Five groups were prospectively studied: mild uncomplicated (n=9), severe uncomplicated (severe anaemia) (n=10) and complicated babesiosis (n=11); and two groups of healthy aparasitaemic dogs: endemic controls from the study area (n=10) and experimental dogs kept in tick-free conditions (n=10). Four measures of RNI production were studied: (i) serum RNI; (ii) serum RNI/creatinine ratio; (iii) fractional clearance of RNI (FC(RNI)); (iv) fractional excretion of RNI (FE(RNI)). Marked elevations of serum RNI occurred in only two dogs, both in the severe uncomplicated group. The highest concentration (log value 5.29 micromol/l) was in a dog that died, but concentrations in the other four dogs that died were unremarkable (0, 0.34, 1.66 and 2.64 micromol/l). Age, appetite and free serum haemoglobin were significant covariates for measures of RNI production. There were no significant differences among the babesiosis groups for serum RNI. Adjustment for creatinine had minor effects on the results. All babesiosis groups had significantly higher serum RNI and RNI/creatinine than the tick-free control group, but did not differ from the endemic controls except for the severe uncomplicated group, which had higher RNI/creatinine. The complicated group had significantly lower FC(RNI) and FE(RNI) than all other groups, except for the tick-free control group, which had similar FE(RNI). The results indicate that, in an endemic area, measures of RNI production are unlikely to be useful indicators of severity or outcome in canine babesiosis.     

Acute phase response in naturally occurring coliform mastitis.

Changes in the activities of serum cytokines and in acute phase response were observed in dairy cows with naturally occurring coliform mastitis. Seven cows with severe mastitis showed systemic and mammary inflammatory response throughout the observation period, and 11 cows with mild mastitis recovered and were able to be milked within 3 days of onset of mastitis. Serum interleukin (IL)-I and tumor necrosis factor (TNF) activities were higher in the severe group than in the mild group at the first appearance of symptoms. Elevated IL-1 activity was evident in the severe group throughout the observation period. Serum alpha-1-acidglycoprotein (alpha1AG) concentration began to rise with the beginning of mastitis in the severe group, and peaked at 9 days. Serum haptoglobin (Hp) concentrations peaked at 3 days, and decreased gradually after 3 days in the severe group. These results showed that there are dynamic changes in serum IL-1 activity and in serum alpha1AG and Hp concentrations in cows with severe coliform mastitis.