Seroprevalence of Toxoplasma gondii infection in sheep and alpacas (Llama pacos) in Chile

Serum samples from 408 sheep from different regions of Chile and 447 alpacas (Llama pacos) from the north of the country were tested for Toxoplasma gondii antibodies. The indirect haemagglutination test (IHAT) was used in both species and the indirect immunofluorescence test (IIFT) was also used on the sheep samples in order to compare the performance of the tests in that species. In both tests, titers ≥1:16 were considered diagnostically significant. Sera from 49 sheep (12%) were positive to T. gondii antibodies by the IHAT. When using the IIFT, 114 sheep sera (28%) were positive. The different results obtained in sheep sera between the tests were significant (p<0.0001). No differences were observed between geographical locations or sex of the sampled sheep regarding serological detection of T. gondii antibodies in sheep. As expected, adult sheep showed higher T. gondii reactivity than young sheep (p=0.0008). The corrected prevalence of toxoplasmosis in alpaca was 16.3% (32 positive out of 447). The rather low prevalence in alpacas may be associated with their extensive management as well as the extreme climatic conditions of The Andes which apparently would not be favorable for the transmission of the parasite.     

Indirect connectivity estimates of amphibian breeding wetlands from spatially explicit occupancy models

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Human Capital Stock and Flow and Economic Growth Analysis: Note

Human capital is becoming recognized as an increasingly important factor in rural economic development. Economic research, however, has not provided clear empirical support of the relationship between human capital investment and economic growth. This paper applies stock and flow concepts to human capital and suggests an operational approach for applying stock and flow concepts to the analysis of the impact of human capital investments through education on economic growth.     

Effects of proteolytic enzymes on the infectivity, haemagglutinating activity and protein composition of bluetongue virus type 20

The effects on virus infectivity, haemagglutinating (HA) activity and polypeptide composition of bluetongue virus type 20 (BTV 20) were determined after digestion with the proteolytic enzymes, chymotrypsin, thermolysin and trypsin. Virus infectivity increased eight to 50-fold after exposure periods which reflected the activity of the proteases. Identical maximum increases in HA activity (i.e. 4096, 1024 and 128 HAU per 0.05 ml with sheep, bovine and human erythrocytes, respectively) occurred with each of the three proteases. Peak increases in virus infectivities and HA activities occurred after similar exposure periods. Outer capsid protein VP2 was the most sensitive virus protein to proteolytic digestion, being cleaved into a number of smaller polypeptides that remained attached to the virus particle. Digestion with chymotrypsin and thermolysin yielded four common cleavage products, designated P93, P76, P54 and P25 according to their estimated molecular weight, which suggested that they shared at least three cleavage sites. VP2 cleavage products resulting from digestion with trypsin differed somewhat from those of chymotrypsin and thermolysin, although the generation of polypeptides P93, P54 and P25.5 suggested the existence of common cleavage sites for the three proteases. Possible mechanisms whereby proteolytic cleavage of VP2 may enhance the infectivity and HA activity of BTV 20 are discussed.     

CORCTATION OF THE AORTA IN A DOG

This paper describes coarctation of the aorta with a large fusiform post-stenotic aneurysm in a 6 year old Great Dane. No clinical signs were attributable to the lesion, which was an incidental finding. The radiological and pathological features of aortic coarctation are described.     

Sulfadiazine-induced allergy in six Doberman pinschers

Treatment with sulfadiazine-trimethoprim caused serious, but reversible, allergic drug reactions in 6 Doberman Pinschers 10 to 21 days after the first drug exposure and/or within 1 hour to 10 days after reexposure. Nonseptic polyarthritis was found in all dogs. Glomerulonephropathy, focal retinitis, polymyositis, skin rash, fever, anemia, leukopenia, and thrombocytopenia were found in some dogs. These clinical abnormalities were typical of an immune-mediated vasculitis and mimicked other immune-mediated disorders. In a drug challenge study, 1 dog was given sulfadiazine and trimethoprim separately. Administration of trimethoprim alone did not result in any abnormalities; however, exposure to sulfadiazine caused recurrence of the polyarthritis, glomerulonephropathy, and focal retinitis within 5 days, suggesting that sulfadiazine likely was the offending agent in all cases. In addition, during the sulfadiazine reexposure, marked complement activation was documented at the time clinical signs were apparent, supporting the suggestion that sulfadiazine caused an immune complex disease (type-III hypersensitivity reaction). Since all dogs were of the same breed, a genetic predisposition of some Doberman Pinschers to react adversely to sulfadiazine was suspected.     

Natural cytotoxicity in the dog: description of two new allogeneic tumour targets

Three canine tumour cells were studied for their susceptibility to cytotoxicity by allogeneic canine natural killer (NK) cells: a lymphoma line, 3132 of B cell origin, and two adherent cell lines emanating from the same non-lymphoid tumour isolate, one (A72F) with a fibroblast morphology and one (A72E) with an epithelioid appearance. Both 3132 and A72E have preliminary evidence of retrovirus infection. Unstimulated canine peripheral blood mononuclear cells, used as the source of NK cells, were able to mediate significant lysis of 3132 and A72F cells at effector cell:target cell ratios of under 50:1, although an 18 h incubation was necessary for maximum cytotoxicity. NK activity against the 3132 tumour cells proved to be variable both within a group of dogs as well as on different occasions utilising the same individual donor. The epithelioid form of the A72 tumour cell line, A72E, had gained a marked resistance to NK lysis, although like the 3132 cells, there is preliminary evidence of persistent retrovirus infection in this cell line. Interestingly the A72F cells were as successful as homologous 3132 cells in the cold target inhibition of labelled 3132 cytotoxicity, while A72E did not. This latter result could indicate that not only do A72F and 3132 share NK determinants recognised by the same NK receptor, but the A72E line has lost this important recognition determinant.     

Myeloproliferative disease in the dog and cat: clinical presentations, diagnosis and treatment

The myeloproliferative diseases may present with a variety of clinical signs including regenerative or non-regenerative anaemias, bleeding diatheses, septicaemia or fever of unknown origin. These signs will raise suspicions of myeloproliferative disease but such disease may also be an incidental finding on routine haematological examination. In either case a bone marrow biopsy will be required for confirmation. Investigation for other causes of anaemia, haemostatic dysfunction or other causes of white cell abnormalities is important in animals where the peripheral blood and bone marrow findings are equivocal or atypical of myeloproliferative disease. Treatment of acute myeloproliferative diseases is presently impractical in veterinary medicine. Therapy of the chronic myeloproliferative diseases depends upon the suppression of the proliferation of the affected clones together with attention to the secondary effects of the disease and to the adverse effects of therapy.     

Prognosis Factors for Survival in Cats After Removal of a Primary Lung Tumor: 21 Cases (1979–1994)

Objective —To identify possible prognostic factors for survival time in cats with a primary lung tumor after surgical excision.
Study Design —Retrospective clinical study.
Animal Population —21 cats with histologically confirmed primary lung tumors removed surgically.
Methods —Medical records for cats treated between 1979 and 1994 at 14 participating veterinary referral hospitals were reviewed.
Results —After surgical resection and recovery, 18 cats died from metastatic disease with a median survival time of 115 days (range, 13 to 1,526 days). Three cats were lost to follow-up at 119 days, 251 days, and 410 days after the surgical procedure. Contingency table analysis to determine if an association existed between clinical findings (breed, age, gender, body weight, clinical signs, duration of clinical signs, and radiographic findings) or histological features and survival time was performed. Only histological morphology of the primary lung tumor showed a significant association with survival time. Twelve cats with moderately differentiated tumors had a significantly longer survival time (median, 698 days; range, 19 to 1,526 days) than the nine cats with poorly differentiated tumors (median, 75 days; range, 13 to 634 days).
Conclusions —Surgical resection of a solitary primary lung tumor in cats is indicated.
Clinical Relevance —A poor prognosis for long-term survival is warranted for those cats having a poorly differentiated primary lung tumor.     

Effects of abdominocentesis technique on peritoneal fluid and clinical variables in horses

Eleven healthy horses underwent 5 repeated abdominocenteses, with either a sharp‐tipped spinal needle or a blunt‐tipped teat cannula to investigate possible differences in success rate, sample volume, depth at which a sample was obtained, length of procedure, complications and cytological variables. Variables were analysed with a repeated‐measures ANOVA or Fisher's exact test (α = 0.05). Success rate, sample volume, length of procedure, occurrence of haemorrhage during the procedure and incidence of grossly visible blood contamination were not different between techniques or over time. Depth at which samples were obtained was greater using a cannula than a needle (P<0.02), and samples were obtained with either technique at a greater depth than abdominal wall thickness assessed via ultrasound (P<0.014). Peritoneal fluid total and differential nucleated cell counts, and total protein concentration did not differ between techniques or over time. Red blood cell count in the least blood contaminated fraction of each sample was not affected by time, but it was lower after needle abdominocentesis than after cannula abdominocentesis (P = 0.04). Swelling of abdominocentesis sites increased with both techniques over time (P<0.05) and was more severe in horses undergoing cannula abdominocentesis (P<0.05). Enterocentesis occurred with a spinal needle in one horse, but no subsequent complications were noted. Both techniques appear to be safe and reliable for abdominocentesis in healthy horses. Using a blunt‐tipped cannula, as opposed to a needle, is likely to result in greater subcutaneous swelling. Both the cannula and needle must be long enough to penetrate well beyond the thickness of the abdominal wall to achieve successful peritoneal fluid collection.