An outbreak of fatal herpesvirus infection in domestic rabbits in Alaska

A herpesvirus infection affecting mini Rex and crossbred meat rabbits was identified in a rabbitry in Alaska. Illness affected over half of the 55 rabbits on the premises, and 16 rabbits died or were euthanatized because of illness. Disease affected all ages from adults to nursing young and occurred over an approximately 2-month period. Clinical signs included conjunctivitis and periocular swelling, ulcerative dermatitis, progressive weakness, anorexia, respiratory distress, and abortion. Hemorrhagic dermatitis and panniculitis were associated with epidermal microvesicular degeneration, dermal and subcutaneous vascular necrosis, and thrombosis. Eosinophilic intranuclear inclusions consistent with herpesvirus were found within the epidermis and superficial follicular epithelium and within mesenchymal cells within the dermis and subcutis. Syncytial cells containing viral inclusions occurred within the epidermal and superficial follicular epithelium. Other findings were hemorrhagic necrosis of the myocardium with rare intranuclear inclusions within stromal cells, multifocal pulmonary hemorrhage, hemorrhage with sinus erythrophagocytosis in lymph nodes, and massive necrosis and fibrin deposition within red pulp of the spleen. A virus isolated from the skin produced syncytia, intranuclear inclusions, and cell lysis typical of herpesvirus in rabbit kidney cells in vitro. The viral isolate was characterized ultrastructurally as an enveloped virus with icosahedral nucleocapsids 100 nm diameter, consistent with a herpesvirus.     

Isolation and pathogenicity of Australian strains of Eimeria praecox and Eimeria mitis

Objective To determine the presence of E praecox and E mitis in Australia, to isolate representative strains of these species from chickens and determine their pathogenicity.
Design Morphological, physiological and cross protection studies were undertaken to confirm the identity of Australian isolates of E praecox and E mitis.
Procedure Oocysts were isolated from a backyard flock at Jimboomba, southeastern Queensland and numbers of E praecox and E mitis enriched by passage in chickens immune to five other species of poultry Eimeria . Oocysts of mean conformation and size of the two species were purified by single oocyst passage. Two isolates that closely matched recorded parameters for E praecox and E mitis were selected and designated JP and JM respectively. The cross protection between the isolates and E acervulina was determined by infection and challenge experiments. The virulence of the two isolates was determined by comparing weight gains of groups of birds inoculated with JP isolate or JM isolate with untreated groups.
Results Isolates JP and JM most closely matched recorded parameters of E praecox and E mitis respectively. Groups of chickens, previously infected with JP and JM isolates, showed no significant protection against infection with E acervulina . In a separate trial, groups of susceptible chickens inoculated with 10⁵ oocysts of JP and JM isolates showed significantly reduced weight gains compared with untreated controls.
Conclusion Isolates JP and JM are E praecox and E mitis respectively, confirming the presence of these species in Australia. These isolates were found capable of causing significant reductions in weight gains in susceptible chickens.     

Vesicles Cytoplasmic Injection: An Efficient Technique to Produce Porcine Transgene‐Expressing Embryos

The use of vesicles co‐incubated with plasmids showed to improve the efficiency of cytoplasmic injection of transgenes in cattle. Here, this technique was tested as a simplified alternative for transgenes delivery in porcine zygotes. To this aim, cytoplasmic injection of the plasmid alone was compared to the injection with plasmids co‐incubated with vesicles both in diploid parthenogenic and IVF zygotes. The plasmid pcx‐egfp was injected circular (CP) at 3, 30 and 300 ng/μl and linear (LP) at 30 ng/μl. The experimental groups using parthenogenetic zygotes were as follows: CP naked at 3 ng/μl (N = 105), 30 ng/μl (N = 95) and 300 ng/μl (N = 65); Sham (N = 105); control not injected (N = 223); LP naked at 30 ng/μl (N = 78); LP vesicles (N = 115) and Sham vesicles (N = 59). For IVF zygotes: LP naked (N = 44) LP vesicles (N = 94), Sham (N = 59) and control (N = 79). Cleavage, blastocyst and GFP+ rates were analysed by Fisher's test (p < 0.05). The parthenogenic CP naked group showed lower cleavage respect to control (p < 0.05). The highest concentration of plasmids to allow development to blastocyst stage was 30 ng/μl. There were no differences in DNA fragmentation between groups. The parthenogenic LP naked group resulted in high GFP rates (46%) and also allowed the production of GFP blastocysts (33%). The cytoplasmic injection with LP vesicles into parthenogenic zygotes allowed 100% GFP blastocysts. Injected IVF showed higher cleavage rates than control (p < 0.05). In IVF zygotes, only the use of vesicles produced GFP blastocysts. The use of vesicles co‐incubated with plasmids improves the transgene expression efficiency for cytoplasmic injection in porcine zygotes and constitutes a simple technique for easy delivery of plasmids.     

Postmortem lesions in the intercarpal ligaments of the equine midcarpal joint

Objective To determine the frequency of damage to the medial palmar intercarpal ligament (MPICL), and the range of sizes of the dorsomedial intercarpal ligament (DMICL) of the midcarpal joint in horses with no history of carpal joint disease.
Materials and methods
Cadaver limbs were collected from 72 horses with no history of carpal joint disease. One hundred and forty-two midcarpal joints were dissected and the MPICL and DMICL were examined. Measurements were made with a digital micrometer.
Results MPICL tearing was present in 88 of 96 joints from horses 2 years and older. Tears were predominantly of the dorsolateral bundle and complete rupture of the dorsolateral and dorsomedial bundles was not observed. Tearing was not present in foals less than 4 months of age and the severity of tearing increased significantly with age (P < 0.0001). Severity of tearing was significantly greater in racing Standardbreds than racing Thoroughbreds (P < 0.01), but there was no significant difference between racing and non-racing horses. The lateromedial thickness of the DMICL ranged from 0.4 mm to 2.6 mm in horses 2 years and older. Lateromedial thickness increased significantly with age, and was significantly greater in racing Standardbreds than racing Thoroughbreds (P < 0.01). There was no significant difference between racing and nonracing horses.
Conclusions Damage confined to the dorsolateral bundle of the MPICL is a common finding in horses over 1 year of age and is probably of little clinical significance. Complete rupture of both dorsolateral and dorsomedial bundles is uncommon in horses with no history of midcarpal joint disease. Variation in size of the DMICL is observed in horses of all ages, but is most marked in 2-year-old horses.     

The survival of platypuses in captivity

Data are presented on the duration of survival of 228 platypuses at six Australian zoos between 1934 and 1988. Only 22.4% of all platypuses survived more than 1 year in captivity. Of 15 living platypuses, 3 had been held in captivity for less than 1 year, 5 for between 1 and 5 years, 6 for between 5 and 10 years and 1 for 21 years. Of 213 platypuses that died in captivity, 81.7% had died within 1 year; most within the first month. The duration of survival was unrelated to the age of animals at acquisition or to sex. The survival rate of animals donated to zoos, including "refugees", was similar to that of purpose-caught animals. Clearly, only a small proportion of platypuses adapted to captive husbandry. The cause of death of most platypuses was not established. However, infectious disease did not appear to be significant. Approximately 28% of deaths were related to inadequate husbandry. Recommendations are made to improve the survival of platypuses in captivity. Research has commenced in zoos to facilitate this goal.