Experimental infection with Toxocara cati in BALB/c mice, migratory behaviour and pathological changes

Experimental inoculations of 1000 Toxocara cati larval eggs were carried out in 18 BALB/c mice. The T. cati eggs used for inoculation were collected from the faeces of naturally infected cats. Euthanasia was performed on two mice on days 1, 2, 3, 4, 5, 6, 14, 21 and 28 post-inoculation (p.i.). Tissue samples were taken for digestion and histopathology. Larvae were recovered from all infected mice and the average of all larvae recovered was 28.3% (95%; CI: 14.1-42.4). Maximum number was obtained from liver on days 1 and 2 p.i.; from the lung on day 2 p.i. and from the brain on day 28 p.i. In muscle, the recovery was high as from day 3 p.i., with the maximum obtained on day 28 p.i. Superficial foci of congestion and haemorrhage were macroscopically observed in the lungs between days 2 and 5 p.i. and in the brain between days 3 and 6 p.i. Microscopic lesions were observed in the liver between days 2 and 14 p.i., with periportal and subcapsule inflammatory infiltrates. In the lungs, haemorrhages and inflammatory infiltrates can be observed in the alveolar parenchyma, close to bronchioles and large blood vessels. In the brain, congestive areas without inflammatory reactions were seen. In muscle, the presence of inflammatory infiltrates and degenerated muscle can be observed surrounding a parasite larva. These same lesions were observed in myocardium and pericardium. The kidneys were congested with inflammatory infiltrates. The inflammatory cells present in all the tissues studied were lymphocytes, neutrophils and a few eosinophils. Formation of granulomas or signs of larva encapsulation were not observed. The migratory pattern of T. cati larvae in BALB/c mice and its tendency to become concentrated in the muscle reinforce the importance of the mouse as a paratenic host for the parasite's cycle in the environment.     

Comparison between Haemophilus parasuis infection in colostrums-deprived and sow-reared piglets

The aim of this study was to compare the development of Glasser's disease in sow-reared and colostrum-deprived piglets. Ninety piglets from a commercial pig farm in Spain were used. The farm was positive for Haemophilus parasuis. Fifty-two pigs were sow-reared (SR) and 38 were colostrum-deprived (CD) piglets. The animals were intratracheally inoculated with H. parasuis serovar 5 and sacrificed at 1, 2 and 3 days post-infection. To assess the development of disease, antibody titers, clinical signs, pathological lesions, microbiological isolation and PCR amplification were compared between the groups. Inoculation of SR pigs did not cause clinical signs or lesions of Glasser's disease. In SR pigs, H. parasuis isolation and specific PCR amplification from tissues showed a very low number of positive samples. In contrast, in CD pigs, inoculation resulted in the typical signs and lesions of Glasser's disease. Positive microbiological isolation and specific PCR products were obtained from the majority of the tissues tested, and no antibodies against H. parasuis were detected. The experimental infection using CD pigs describes a successful method to study this microorganism and confirms the important role that maternal antibodies play in protection against clinical signs and disease.     

Comparative fluke burden and pathology in condemned and non-condemned cattle livers from selected abattoirs in Zambia

After dissecting 70 condemned and 32 non-condemned cattle livers collected from Lusaka, Chisamba, Mongu and Senanga abattoirs and Turnpike slaughter slab, significantly higher numbers of liver flukes (Fasciola gigantica) (P < 0.001) were found in the condemned livers (mean +/- SD = 100.6 +/- 16.7) than in the non-condemned livers (mean +/- SD = 0.7 +/- 0.5). Liver flukes found in 9.4% of the non-condemned livers suggest that abattoir records of liver inspection may underestimate F. gigantica infections. Average faecal fluke egg counts from animals with condemned livers (5 eggs per gram [EPG]) were significantly higher (P < 0.001) than in animals with non-condemned livers (0.8 EPG). No correlation was found between egg counts and number of flukes. Fibrosis and calcification were common in condemned livers, being severest in the vicinity of the bile ducts. Only two (6.3%) of the non-condemned livers showed pathological changes on the liver edges. The severe liver damage and high worm burden may explain low production levels experienced in cattle in Zambia maintained under traditional systems of management where worm control and good management programmes are rarely practiced.     

Primary Aspergillus and Fusarium keratitis in a Holstein cow

A 5-year-old female Holstein cow was examined for ocular discharge, periorbital swelling, an area of full-thickness corneal cellular infiltrate, fibrin, hypopyon, diffuse corneal edema, and miosis. The patient was diagnosed with a corneal stromal abscess and secondary anterior uveitis. Histopathology, mycotic culture, and polymerase chain reaction positive for Aspergillus and Fusarium DNA confirmed the presence of fungal infection. Response to therapy was adequate, and follow-up with the patient 1 year after diagnosis revealed a focal area of corneal fibrosis.     

Na(+), K(+)-ATPase content in skeletal muscle of dogs with pituitary-dependent hyperadrenocorticism

Several hormones regulate Na⁺, K⁺-ATPase content in the muscle cell membrane, which is essential for maintaining muscle cell excitability. Chronic glucocorticoid excess is associated with muscle weakness and reduced endurance. We hypothesized that chronic glucocorticoid excess affects Na⁺, K⁺-ATPase content in canine skeletal muscle, and contributes to reduced endurance and muscle weakness associated with pituitary-dependent hyperadrenocorticism (PDH) in dogs. Therefore, Na⁺, K⁺-ATPase content in skeletal muscle was evaluated before and after hypophysectomy and hormone replacement (cortisone and l-thyroxin) in dogs with PDH (n = 13), and in healthy controls (n = 6). In addition, baseline and exercise-induced changes in plasma electrolyte concentrations and acid–base balance were evaluated before and after hypophysectomy in dogs with PDH. Na⁺, K⁺-ATPase content of gluteal muscle in dogs with PDH was significantly lower than in control dogs (201 ± 13 pmol/g versus 260 ± 8 pmol/g wet weight; P < 0.01). Similar differences were found in palatine muscle. After hypophysectomy and on hormone replacement, Na⁺, K⁺-ATPase was increased (234 ± 7 pmol/g wet weight). Both plasma pH and base excess in dogs with PDH (7.44 ± 0.01; 1.7 ± 0.6 mmol/l, respectively) were significantly higher (P < 0.05) than after hypophysectomy and hormone replacement (7.41 ± 0.01; −0.2 ± 0.4 mmol/l, respectively). Exercise induced respiratory alkalosis, but did not result in hyperkalemia in dogs with PDH. In conclusion, chronic glucocorticoid excess in dogs with PDH is associated with decreased Na⁺, K⁺-ATPase content in skeletal muscle. This may contribute to reduce endurance in canine PDH, although dogs with PDH did not exhibit exercise-induced hyperkalemia. Na⁺, K⁺-ATPase content normalized to values statistically not different from healthy controls after hypophysectomy and hormone replacement.     

Clinical and pathological studies on intoxication in horses from freshly cut Jimson weed (Datura stramonium)-contaminated maize intended for ensiling

Spontaneous intoxication in 34 horses after ingesting freshly harvested maize that was to be used for ensiling and heavily contaminated with young Datura stramonium plants, is described. The clinical status of all horses was monitored for 7 days, and included body (rectal) temperature, respiratory and heart rates, colour and moistness of visible mucosae, changes in pupil size, appetite, thirst, general behaviour, locomotion, sensory perceptions, urination and defaecation. The intoxication was accompanied by altered clinical status, namely mild hyperthermia, tachycardia, polypnoea, dyspnoea and shallow breathing, mydriasis, dry oral, rectal, vaginal and nasal mucosae, acute gastric dilatation and severe intestinal gas accumulation, anorexia to complete refusal of feed, decreased or absent thirst, absence of defaecation and urination. As a result of the treatment, the clinical parameters normalised between days 2 and 5. Necropsies and pathological studies were performed on two horses that died, revealing toxic liver dystrophy, cardiac lesions and substantial dystrophic and necrotic processes in the kidneys. The observed clinical signs, the pathomorphological changes and the applied therapy could be used in the diagnosis, differential diagnosis, prognosis and treatment of Jimson weed intoxication.