A review of porcine reproductive and respiratory syndrome virus in Dutch breeding herds: population dynamics and clinical relevance

Understanding the spread of porcine reproductive and respiratory syndrome virus (PRRSV) in pig populations is essential to the development of effective PRRS prevention and control strategies. Moreover, knowledge of the field dynamics of PRRSV in pigs will provide insights into the clinical relevance of PRRS, and will enable the targeting of interventions. This review of PRRSV includes discussion on the occurrence of outbreaks, the persistence of infection and the fade-out of infection in Dutch breeding herds. The dynamic character of PRRSV infections in endemically infected herds and the relevance of the disease under Dutch field conditions are also highlighted. Furthermore, several strategies aimed at controlling the spread of PRRSV are discussed.     

Extrinsic cardiac nerve segments in the domestic dog (Canis familiaris- Linnaeus, 1758). Comparative study in young and adult dogs

In this paper, important connections between the two main contingents of the autonomic nervous system, intrinsic and extrinsic visceral plexus were analysed. Concerning heart innervation, the territories of extrinsic innervation are very important in the treatment of congenital or acquired cardiopathy, thoracic neoplasia and aortic arch persistence, among others. This research compared young and adult extrinsic cardiac innervation and described the surgical anatomic nerve segments. Animals were perfused with a 10% formaldehyde solution in PBS (0.1 m) (pH 7.4) and submitted to macro- and meso-scopic dissection immersed in 60% acetic acid alcoholic solution and 20% hydrogen peroxide aqueous solution. The nerve segments were assigned as: right vagus nerve segment, left vagus nerve segment, right middle cervical ganglion segment, left middle cervical ganglion segment, right caudal laryngeal nerve segment, left caudal laryngeal nerve segment, right phrenic nerve segment and left phrenic nerve segment.     

Recurrent fever as the only or predominant clinical sign in four dogs and one cat with congenital portosystemic vascular anomalies

Fever is not considered a typical clinical sign in animals with portosystemic vascular anomalies (PSVA). In a time period of 8 years, PSVA was diagnosed in 23 cases (20 dogs, 3 cats) at the Animal Hospital of the University of Zurich. Of these, recurrent fever was the only, the predominant or an early sign in 5 animals. Fever and associated unspecific clinical signs like lethargy, inappetence, and reluctance to move were present for weeks to months before the final diagnosis of PSVA was made. It was the lack of typical and well-known signs of PSVA that obscured and delayed the diagnosis. Therefore, PSVA should be included in the differential diagnosis of animals with fever of unknown origin (FUO).     

Microbial cross-contamination by airborne dispersion and contagion during defeathering of poultry

1. A readily identifiable strain of Escherichia coli K12 was used as a 'marker' organism to determine the sources, routes and patterns of microbial cross-contamination during mechanical defeathering of broiler chicken carcases. 2. Inoculation of scald water with the marker organism led to a relatively even pattern of carcase contamination during subsequent defeathering. Microbial cross-contamination was greater by this route of inoculation than by either surface inoculation of a 'seeder' carcase or oral inoculation of a live bird one day before slaughter. 3. Dispersal of the marker organism was strongly influenced by the mechanical action of the defeathering machines. Forward transmission of the marker occurred by aerosol or large airborne droplets and particulates such as feathers. Moving carcases through the defeathering machines when these were non-operational clearly reduced backward transmission of the marker. 4. Although microbial dispersal was unaffected by increasing the spacing between individual carcases or installing a water curtain at the entry and exit of the defeathering machines, shielding of carcases with aluminium baffles reduced counts of the marker organism from contaminated carcases by > 90%. 5. The results imply that microbial cross-contamination of broiler chicken carcases during defeathering occurs mainly via the airborne route, which could be contained by physical means.     

Production of polyclonal antisera against feline immunoglobulin E and its use in an ELISA in cats with experimentally induced asthma

Serum samples from six cats with experimentally induced asthma were used to purify feline IgE using gel filtration and affinity chromatography. The resultant IgE, evaluated for purity by immunoelectrophoresis (IEP) and reactivity by Prausnitz-Kustner (PK) testing, was used to develop polyclonal rabbit anti-feline IgE antisera. Using reverse cutaneous anaphylaxis (RCA), the antisera were determined to be specific for feline IgE. The polyclonal rabbit anti-feline IgE antiserum was then validated in an allergen-specific ELISA. Serum samples from an additional five asthmatic cats sensitized with Bermuda grass allergen (BGA) were evaluated prior to sensitization, after parenteral sensitization, and after aerosol sensitization and challenge. A significant increase in serum BGA-specific IgE was noted over time.     

Congenital cardiac diseases in dogs: a retrospective analysis

In a time period of 6 years, 158 congenital cardiac defects were diagnosed in 146 dogs at the Clinic for Small Animal Medicine University of Zurich. In respect to all dogs with cardiac disease, these were 23.5% of the cases. Most common defects were subaortic stenosis (SAS, 31.5%), pulmonic stenosis (PS, 23.3%), ventricular septal defect (VSD, 14.4%), patent ductus arteriosus (PDA, 13.7%) and tricuspid dysplasia (TD, 7.5%). Complex defects were found in 8.2% of the dogs. Although single dogs per breed were affected by various defects, some breed-related tendencies could be observed. We found PS more numerously in boxers and Jack Russell Terriers whereas SAS, VSD and TD were also found in breeds reported to be predisposed. Congenital cardiac defects are an important clinical entity, and knowledge of prevalence is helpful when considering the differential diagnosis and for making a tentative diagnosis in an individual case.     

Modification of standard freezing media to limit capacitation and maximise motility of frozen-thawed equine spermatozoa

OBJECTIVE: To investigate cryopreservation-induced capacitation-like changes in equine spermatozoa frozen in three different media using chlortetracycline (CTC) fluorescence staining analysis. PROCEDURE: Semen collected from three stallions was diluted in one of three centrifugation media and, after centrifugation and removal of supernatant, extended in corresponding freezing media containing additional egg yolk, glycerol, lactose and Equex paste. The semen was frozen in 5 mL straws and the spermatozoa assessed for motility and membrane quality after thawing. RESULTS: Following centrifugation, spermatozoa diluted with modified Kenney's Centrifugation Medium (MKCM) displayed a higher percentage of (normal) F pattern (94.3%) compared with spermatozoa in Kenney's Centrifugation Medium (KCM) (84.9%) and Glucose-EDTA Centrifugation Medium (GECM) (85.2%). Conversely, the percentage of spermatozoa displaying the (capacitated) B pattern was higher in the KCM (14.1%) and GECM (13.8%) than in the MKCM (5.0%). Following freezing-thawing, there were lower percentages of spermatozoa displaying the AR (acrosome reacted) pattern in modified Kenney's Freezing Medium (MKFM) (45.6%) compared with Kenney's Freezing Medium (KFM) (61.4%) and lactose-EDTA Freezing Medium (LEFM) (61.1%). There was a correspondingly higher percentage of spermatozoa displaying the B pattern in MKFM (52.3%) compared with KFM (37.9%) and LEFM (38.6%). There was no significant difference between the freezing media in the percentage of spermatozoa displaying the F pattern. The percentage of progressively motile spermatozoa was also influenced by the type of freezing medium (P < 0.001). Post-thaw percentages of progressively motile spermatozoa, frozen in MKFM, KFM, and LEFM, were 31.4, 25.8 and 23.3%, respectively. CONCLUSION: MKFM was the preferred medium for cryopreservation of equine spermatozoa due to its superior protection against changes in motility and membrane quality compared with the other freezing media studied.     

Paratuberculosis: eradication, control and diagnostic methods

At the beginning of the twentieth century, the dairy industry and cattle breeding organisations initiated a programme to control infectious diseases by means of a complex system of rewards and penalties. The history of programmes to control paratuberculosis in sheep, goats, and cattle in various countries is described. The vaccination of young animals (especially goats and sheep) seems to be an effective measure in the prevention of clinical paratuberculosis, although changes in management and hygiene practices are also important. A control programme for infectious cattle diseases has a number of phases (a life cycle) and different components. Two components are essential for success, namely, open and regular communication with farmers, veterinary practitioners, and other people involved, and a good registration and identification system for cattle, herds, and veterinary practitioners. The principles and different levels of control of paratuberculosis are discussed. The Dutch paratuberculosis programme is divided in two parts: an intensive programme based on test and cull and an extensive programme based on education. The intensive programme has ten herd status levels: 5 to 10 for non?suspect herds and 1 to 4 for infected herds or herds of unknown status. The higher the status, the greater the chance that a herd is free of paratuberculosis. An outline is given of the Dutch paratuberculosis programme. Diagnostic methods are summarised. Future developments regarding vaccination and control or acceptance of paratuberculosis are discussed.