Animal definition: a necessity for the validity of animal experiments?

In most scientific journals, experimental animals are described poorly. Whether this is scientifically justified is discussed in this article. It was concluded that when laboratory animals are used in scientific experiments, which almost always are of a quantitative nature, a detailed animal definition is imperative.

Experimental infection of dogs with the nasal mite Pneumonyssoides caninum.

A successful experimental transmission of the canine nasal mite, Pneumonyssoides caninum, is described. Some 11 weeks after repeated systemic ivermectin treatment, four Beagles were inoculated via the right nostril with 20 P. caninum mites of different sexes and life stages, obtained at the necropsy of an infected dog. The inoculated dogs and a matching uninoculated control were observed for clinical signs for 14 weeks and then euthanised. Vague upper respiratory signs and a transient minor increase in the number of eosinophils in peripheral blood were recorded in the inoculated dogs. At necropsy 4-12 P. caninum mites were found in the nasal cavities and sinuses of the inoculated dogs, but none in the control. In three out of the four infected dogs mites were found in both the right and left nasal cavities and sinuses of the skull. Since in no case more mites than the number used for inoculation were detected it is not clear if the mites managed to reproduce in the dogs. Inflammatory lesions were seen most consistently in the olfactory mucosa, respiratory mucosa and tonsils, and growth of opportunistic bacteria was observed in the tonsils of the infected dogs. The inflammatory lesions seen in the olfactory mucosa may explain why dogs infected with P. caninum sometimes appear to suffer from impaired scenting ability.

A bovine viral diarrhoea/mucosal disease-like syndrome in moose (Alces alces): investigations on the central nervous system.

A disease of unknown aetiology has been observed in moose. The animals showed signs of a bovine viral diarrhoea/mucosal disease-like syndrome, and central nervous disturbances. Brains from adult female moose were investigated by means of histology, immunohistochemistry, electron microscopy, virology, and bacteriology. The results indicate that the nervous signs were not associated with a spongiform encephalopathy. The lesions suggest a viral aetiology, although all the virological investigations have so far proved negative.

An ultrastructural study of spontaneous chronic lung lesions in asymptomatic rabbits.

An electron microscopical study of chronic lung lesions in 12 clinically healthy, purpose bred laboratory rabbits (eight of which were free from infections with known respiratory pathogens but 4 of them carried a natural B. bronchiseptica infection) revealed focal chronic interstitial pneumonia, vascular changes and focal chronic bronchiolitis. In addition, severe endothelial changes and intravascular deposition of collagen were observed in septal capillaries. In type I pneumocytes and septal capillary endothelium we noticed numerous rounded structures, 70-90 nm in diameter, which consisted of a limiting two layer membrane enclosing an irregularly rounded electron-dense centre surrounded by a more electron-lucent halo. These structures appeared free in the cytoplasm, or they were attached to or apparently budding from membranes other than the plasmalemma. Particles located extracellularly were not found. Whether the structures described were involved in the genesis of the lesions found remains to be elucidated.

A bovine herpesvirus (BHV-4) as passenger virus in ethmoidal tumours in Indian cattle.

A herpesvirus was isolated from tumours of the ethmoidal mucosa in two of three head of cattle in the State of Kerala, India. The virus designated M40 was cytopathic for a variety of cultured bovine and porcine cells and it did not kill suckling mice or chicken embryos. Sera from tumour-bearing cattle and goats reacted with the M40 virus. Immunofluorescence tests with FITC-conjugated IgG from a bovine monospecific antiserum to bovine herpesvirus 4 (BHV-4) stained the M40 virus specific antigen in infected cells. Experimental infection of goats with the M40 virus did not result in development of tumours. This virus is therefore considered to represent a "passenger" virus. A great similarity was found between restriction patterns of DNAs extracted from M40 virus and the strain 66-P-347, a reference strain of the BHV-4 group.

Species of the genus Elaphostrongylus parasite of Swedish cervidae. A description of E. alces n. sp.

A description of Elaphostrongylus alces n. sp., a parasite of moose (Alces alces L.), is given. The main features differing E. alces n. sp. from the other two investigated species are the bottle shaped oesophagus and the oval bursa, which is about 150 microns x 200 microns. E. rangiferi Mitskevith, 1960, a parasite of reindeer (Rangifer tarandus tarandus L.) and E. cervi Cameron, 1931, a parasite of red deer (Cervus elaphus L.) have both a club shaped or cylindrical oesophagus and a circular bursa. The bursa of E. rangiferi is about 160 microns in diameter, and the bursa of E. cervi is about 190 microns. Each species has been found only in its normal host.

Occurrence of intracytoplasmic inclusion bodies in the digestive epithelium of fallow deer (Dama dama L).

Intracytoplasmic inclusion bodies were observed in the digestive epithelium of fallow deer (Dama dama L) suffering from bovine virus diarrhea/mucosal disease. Similar inclusion bodies were also found in the ruminal epithelium of fallow deer subjected to overfeeding by supplementary food. Inclusion bodies were not found in the upper alimentary mucosa of clinically healthy deer but were frequently found when these tissues were subjected to autolysis. At electron microscopical studies the inclusion bodies were found to consist of granular protein-like material encircled by a single membrane. Such inclusion bodies may constitute a non-specific degenerative cell response which could be elicited by diverse factors including autolysis.

Effect of high 131I doses to the thyroid gland on tumorigenicity of 90Sr and 90Y in mice.

The incidence of tumors was studied in mice injected with 90Sr only or with 90Sr in combination with high amounts of 131I. The high 131I-dose to the thyroid gland was necrotizing to the glandular tissue and the main aim of the investigation was the possible effects of the thyroidal destruction on the formation of bone tumors. After correction for competing mortality, no significant difference in the frequency of bone tumors could be found between 90Sr-treated and (90Sr + 131I)-treated mice. The incidence rate of bone tumors, however, was higher in mice with radiogenically destroyed glands than in those with intact glands. The limitations of using the concept of 'actuarial tumor incidence' in correction for competing mortality in animal experiments are discussed. Large numbers of lymphatic tumors were found in all animal groups. The frequencies of such tumors were independent of the radiation doses but their incidence rates were shortened in a dose dependent manner. Other, directly or indirectly radiation induced tumors were observed.

[A new onchocercal parasite, Onchocerca alcis n. sp., parasite of the moose Alces alces in Sweden]. / Nouvelle Onchocerque, Onchocerca alcis n. sp. parasite de l'élan, Alces alces, en Suède.

Among the onchocercids of cervids, Onchocerca alcis n. sp., a parasite of the moose, Alces alces, belongs to that small palearctic group of evolved onchocercids consisting of O. jakutensis, O. garmsi and O. tarsicola. It is distinguished from its most closely related species, O. jakutensis, primarily on the characters of the lateral chord and cuticle, its greater spicule ratio, and the characteristic shapes of the anterior and posterior extremities of female worms.