Evaluation of a new immunocapture test for the diagnosis of ovine brucellosis caused by Brucella melitensis

A new immunocapture technique has been applied to the diagnosis of ovine brucellosis under experimental conditions. The tests were made on a serum bank derived from both young and adult ewes vaccinated conjunctivally with the Rev 1 strain at a dose of 10(8) to 10(9) colony-forming units. Adult ewes were infected experimentally two-and-a-half years after they had been vaccinated and the results were compared with an unvaccinated control group. The condition of each animal in terms of infection with Brucella melitensis was determined by clinical and bacteriological investigations. The development of the immune response was compared by the rose bengal test, the complement fixation test, the Coombs' test and the immunocapture technique for 180 days after the vaccination and for 410 days after the experimental infection, that is, the two following gestations. The results suggest that the new technique is more specific in animals vaccinated conjunctivally, regardless of their age when they were vaccinated. After the experimental infection, significantly (P < 0.05) fewer of the vaccinated sheep which were free of clinical signs and were not excreting B melitensis reacted positively to the test.     

Silica Urolithiasis in the Dromedary Camel in a Subtropical Climate

In 1998, two cases of silica urolithiasis occurred in castrated male dromedaries on an intensive camel farm in the Canary Islands. The immediate attributable cause was the ingestion of large amounts of silica in the feed, estimated as 84.44 g/day. An associated cause was the low level of salt in the diet. Daily ingestion of salt from feed and water was estimated to be 21.8 g (8.6 g of sodium). Seventy-six castrated males from the same farm were divided into four groups: group A received 30 g of salt daily; group B received 40 g; group C received 60 g; and group D received no added salt in the diet (control). The animals were maintained on these dietary regimes for 2 years. No animals from groups A, B or C suffered overt urinary retention. One animal from group D had an obstructive urinary retention 10 months after the study commenced. Thus, 52 g of salt daily appears to be sufficient to prevent urinary retention in dromedaries raised in a subtropical climate.     

Delayed acute capture myopathy in three roe deer

Delayed acute capture myopathy is the term used to describe the clinical syndrome observed in three roe deer captured by drive-nets and transported to an enclosure for scientific purposes. The animals died 48 h, 60 h and 8 days after being captured. The simultaneous deaths coincided with a previous episode of deliberate human disturbance. The histopathological findings were indicative of acute myopathy and myoglobinaemic nephrosis. These could be related to an ataxic myoglobinuric syndrome brought on by capture and transport operations. The lack of clinical signs and negative prognosis indicators in the period between capture and just before death. the absence of gross muscular lesions in the animal that died after 8 days post-capture, the simultaneous deaths of animals captured at different times and the evidence of deliberate human disturbance in the enclosure are suggestive of death triggered by a second stress episode.     

Differential serological testing by simultaneous indirect immunofluorescent antibody test in canine leishmaniosis and ehrlichiosis

A mixed indirect fluorescence antibody test (IFAT), based on cultured promastigotes Leishmania infantum and formol-inactivated suspension of cells infected with the bacteria Ehrlichia canis, was applied to make a differential diagnosis between canine ehrlichiosis and leishmaniosis. A titre greater than 80 was considered positive for antibodies to E. canis and suggestive of antibodies to L. infantum. Positive sera were titrated subsequently by serial dilutions to confirm antibodies positive to Leishmania and establishing the antibody titre of both pathogens. Fluorescence was absent with negative control sera and background staining was minimal. No serological cross-reactions between positive sera for L. infantum or E. canis were detected. Results obtained by mixed IFAT did not differ when the same serum IFAT standard was compared. The test showed equivalent sensitivity (100%). The specifities were 100% for L. infantum and 98.5% for E. canis. The equivalence in sensitivity was confirmed by calculating the correlation coefficient between IFAT standards and mixed IFAT (r>or=0.99 for both pathogens). The results of our investigations demonstrated that mixed IFAT is a specific means of establishing serological differential diagnosis of canine leishmaniosis and ehrlichiosis.     

Dynamics in serum of the inflammatory markers serum amyloid A (SAA), haptoglobin,fibrinogen and alpha2-globulins during induced noninfectious arthritis in the horse

Despite the importance of noninfectious joint diseases in equine medicine, little is known about the acute phase response which may be elicited if the local inflammatory process of noninfectious arthritis is sufficiently strong, Therefore the aim of this study was to monitor the systemic inflammatory response during experimentally-induced noninfectious arthritis by studying the dynamics in serum of the acute phase proteins serum amyloid A (SAA), haptoglobin, fibrinogen and alpha2-globulins. Twenty-four Standardbred horses, age 3-7 years, found healthy on thorough clinical, radiological, haematological and serum biochemical examination, were injected aseptically into the right midcarpal joint with amphotericin B. Blood samples were drawn before induction of arthritis (0 h), and at 8, 16, 24, 36 and 48 h postinduction and then on Days 3, 4, 5 and 15 postinduction. All horses developed lameness with joint effusion and joint heat as well as increased respiratory rate, heart rate and body temperature. The lameness started to decline after 24-36 h and, in most animals, systemic signs disappeared on Day 2 postinjection. The concentration of the acute phase proteins increased following induction of arthritis. The SAA concentrations were higher than baseline concentrations from 16 h postinduction and were maximal at 36-48 h (227 times baseline concentration). The haptoglobin concentrations were higher than baseline concentrations from 24 h and were maximal at 48-96 h (1.14 times baseline concentration). The maximal concentrations of fibrinogen were seen between 36-72 h postinjection and increased on average 0.87 times from baseline concentrations. The fibrinogen concentrations were higher than baseline concentrations from 24 h postinjection. Alpha2-globulins concentrations showed a minor increase and increased 0.55 times from baseline concentrations. The markers had returned to baseline concentrations by Day 15. Our results demonstrate that amphotericin B-induced arthritis in a single joint gives rise to a systemic acute phase response measurable as increased concentrations in serum SAA, haptoglobin, fibrinogen and alpha2-globulins during the first 2 weeks of the condition and, thereby, that such an increase need not be indicative of infectious arthritis. Further research should be aimed at determining whether chronic noninfectious arthritis in the horse gives rise to increased acute phase protein concentrations in serum.     

Simulation model of within-herd transmission of bovine tuberculosis in Argentine dairy herds

Transmission of bovine tuberculosis was quantified in three dairy herds located in south Santa Fe Province, Argentina. Using estimates of Mycobacterium bovis transmission (β) and a Reed–Frost simulation model, the prevalence of tuberculosis infection in the study herds over time was investigated. The Reed–Frost model was modified by incorporating randomness in both β and the incubation period () of M. bovis. The mean estimated herd β was 2.2 infective contacts per year and did not differ significantly between the study herds. Modeling as Poisson distributed (mean 24 months) best fit the observed prevalences. Infection was predicted by the model either to spread quickly (<10 years) within a herd and reach a high prevalence (>50%), or to persist at a low prevalence (<5–10%). The model was robust, predictions were realistic and the mean β estimated was consistent with previous studies of bovine tuberculosis.     

Effect of luteinising-hormone in vivo on ovarian cell subpopulations of newly-hatched chicks

1. We analysed the number and size of different ovarian cell subpopulations of newly-hatched chicks by ovarian cell suspension count and morphometric/stereological methods as well as delta5-3beta-hydroxysteroid dehydrogenase (delta5-3beta HSD) activity in these cells treated in vivo with LH during embryonic development. 2. Fertile White Leghorn eggs received 1 microg LH applied to the chorioallantoic membrane on days 13, 15, and 17 of incubation. All animals were killed within 24 h after hatching, the left ovary was dissected and processed. 3. The results indicate that the number of germ, pregranulosa, interstitial and undifferentiated cells was not affected by LH treatment. However, we observed an increase in the size of individual interstitial cells of the ovarian medulla. In these cells, delta5-3beta HSD activity was increased in response to LH. 4. These findings suggest that LH does not exert a proliferative effect on the cells of the prefollicular ovary of the chick and that interstitial cells can be target cells for LH, increasing their steroidogenic activity due to LH treatment.