Comparison of three serological tests and an interferon-gamma assay for the diagnosis of paratuberculosis in experimentally infected sheep

OBJECTIVE: To compare the diagnostic performance of a complement fixation test, an agar gel immunodiffusion test, an enzyme-linked immunosorbent assay, and a whole-blood interferon-gamma assay for paratuberculosis in 14 sheep experimentally infected with Mycobacterium avium subsp paratuberculosis. EXPERIMENTAL DESIGN: Longitudinal study. RESULTS: The IFN-gamma assay detected more experimentally infected sheep, and earlier, than any of the serological tests. None of the antibody assays was able to detect all sheep with histologically confirmed paratuberculosis. CONCLUSIONS: The superior performance of the IFN-gamma assay in detecting infected sheep in this small experimental population warrants its further evaluation in a larger population of sheep naturally exposed to M a paratuberculosis.     

Dieldrin poisoning of dogs

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One of the obvious points of life today is the rapid pace of technological change. The veterinary profession worldwide, and in New Zealand, is not immune from such change. Most of the changes that professionals are now learning to live with are changes that they themselves helped to bring about. Over the last twenty years, and especially over the last ten years in New Zealand, the demand for veterinary skills and advice has increased dramatically. Prior to 1937, veterinary science in New Zealand was an infant profession. Since then the first stage was “selling” farmers an awareness of what veterinary science could do for them. The second stage saw the formation of the Veterinary Services Council, in which efforts were made to ensure equitable distribution of veterinarians, especially in rural areas. The third stage was trying to cope with demand. Today, numbers are reaching the stage at which we can afford the luxury of more detailed planning. The aim is to ensure that all facets of the potential of veterinary science for increasing live-stock production, furthering animal welfare, and in quality control of human food-stuffs, are adequately and efficiently exploited. This is the stage at which multi- disciplinary co-operation will have to be seriously considered.     

Airway hypersensitivity induced by Ascaris suum extract in New Zealand Romney sheep

Sheep from local farms with and without previous exposure to pigs were tested for their skin and airway responses to a commercial Ascaris suum antigen. There was an immediate reaction to intradermal injection of the antigen in 90% of 101 sheep. A bronchial provocation test by aerosol of the same antigen was undertaken on 43 of the sheep with a positive skin reaction. About 70% of sheep showed an immediate airway response to the antigen as an aerosol, reflected as a significant increase in airway resistance and/or decrease of dynamic lung compliance. The mean peak airway resistance and mean lowest dynamic lung compliance were 165% above and 61% below their baselines, respectively. No significant changes were recorded when the same animals were given an aerosol of phosphate buffered saline. Similarly, no correlation was found between the degree of skin reaction and the magnitude of bronchoconstriction (p>30.05). The sheep with previous exposure to pigs showed no significant differences in airway responses to antigen challenge, although they showed significantly greater skin reactions than those without exposure to pigs. These results indicate that the majority of Romney sheep in the Manawatu have a natural skin and airway sensitivity to A. suum antigen and may therefore be used as an animal model to study human airway hypersensitivity. The origin of this sensitivity has yet to be determined.     

Cerebrocortical necrosis (Polioencephalomalacia) in a goat

Extract

A Saanen goat, approximately two years old, which had been tethered on clean pasture, showed sudden onset of blindness, collapse, and aimless paddling movements of the legs when stimulated by touch. Respirations were deep and irregular. The temperature was normal. Death ensued 48 hours after the onset of symptoms.     

The occurrence of paradontal disease in sheep in relation to superphosphate topdressing,stocking rate and other related factors

Extract

The serological diagnosis of bovine leptospirosis, especially in areas where several serotypes of Leptospira are known to exist, would be greatly facilitated if a method could be used to screen sera for evidence of infection irrespective of the causal serotype. Once infection has been diagnosed, a more specific serological test could be employed to determine the serotype responsible. At least 4 serotypes of Leptospira are known to infect cattle in New Zealand, namely, pomona, hardjo, ccpenhageni and ballum.     

Yeasts of the genus Pityrosporum in the mammalian external auditory canal with special reference to the dog

Abstract

Extract

The genus Pityrosporum (Lodder and Kreger van Rij, 1952 Lodder, J. and Kreger van Rij, N. J. W. 1952. The Yeasts, A Taxonomic Study Amsterdam 1952 [Google Scholar]) includes yeasts which reproduce by budding on a broad base and do not produce mycelium or pseudomycelium. They .have no fermentative ability and grow very slowly on malt agar. Some species such as P. ovale, the type species of the genus, require oleic acid or some fatty substance for growth. Gustafson (1955 Gustafson, B. A. 1955. Otitis Externa in the Dog. Stockholm 1955 [Google Scholar]) has suggested that the genus should include a non-lipophilic yeast isolated from the ears of dogs with otitis externa. This organism has been provisionally named Pityrosporum canis and can be briefly described as an ascosporogenous yeast reproducing by budding on a broad case. Most of the cells are oval, no mycelium or pseudomycelium is formed, and fermentative ability is absent. From a number of experiments involving the introduction of P. canis into the ears of normal dogs, Gustafson concludes that it can be a cause of otitis externa.     

Subpleural lymph nodes in goat lungs

Subpleural lymph nodes were found in more than 4% of 3245 goat lungs during a slaughterhouse survey of respiratory disease. Their frequency varied between flocks from 2% to as much as 27%. They were more common in feral goats than in crossbreds or Angoras. Their numbers were positively associated with carcass weight and the number of nodular muellerius lesions on the lung surface. Their distribution and architecture were different from the pulmonary lymphoid nodules described in cattle with dictyocaulus re-infection syndrome.     

Experimental infection with BCG as a model of tuberculosis in the brushtail possum (Trichosurus vulpecula)

AIMS: To study the development and progression of lesions produced following experimental inoculations of possums with Bacille Calmette-Guérin (BCG) Pasteur Strain 1173P2 and to compare these with lesions that occurred following natural Mycobacterium bovis infection.

METHODS: Possums were inoculated with 5 x 10⁶ colony forming units (cfu) of BCG via the intra-dermal (I/D) route into the dorsum of the neck (n=38) or the left brachium (n=7), orally (n=10), via the endo-bronchial (E/B) route (n=12), or intravenously (I/V) (n=10, half of which received 5 x 10⁶ cfu and half of which received 5 x 10⁷ cfu of BCG). The possums were humanely killed between 1–4 weeks post inoculation (p.i.), and the nature and distribution of lesions examined grossly and histopathologically.

RESULTS: The distribution of lesions following I/D inoculation via either route was similar to that of the natural disease, but there were few lesions in the lung. Endo-bronchial inoculation resulted in pulmonary disease but produced few lesions outside the respiratory tract. Lesions produced by I/V inoculation were similar in distribution to those seen in terminally ill tuberculous possums. No lesions were produced following oral inoculation. Regression of lesions commenced after 3 weeks p.i.

CONCLUSIONS: Although the phenomenon of lesion resolution restricts the use of BCG to the study of early lesion development, it avoids the overwhelming disease induced using M. bovis and thus allows the early phases of the development and progression of tuberculosis in this species to be observed. Intra-dermal inoculation produced evidence that infection through the skin is associated with lesions in superficial lymph nodes, whereas pulmonary disease was associated with E/B inoculation. The results are consistent with the hypothesis that both percutaneous and respiratory routes are important in natural infection of possums with M. bovis.