Streptococcus suis serotypes associated with disease in weaned pigs

Streptococcus suis was recovered from 9 outbreaks of septicaemia and meningitis in weaned pigs between 1979 and 1983. Fifteen isolates from 7 outbreaks were identified as S. suis type 9, and 3 isolates from 2 outbreaks as S. suis type 2. Three further isolates of S. suis type 2 and an isolate of S. suis type 3 were recovered from cases of bronchopneumonia in weaned pigs from 4 other piggeries.     

Isolation of Mycoplasma synoviae from infectious synovitis of chickens

This report describes the first isolations of Mycoplasma synoviae from the synovial sheaths and joints of commercial chickens affected with synovitis in Australia. Over 4 years 3 separate outbreaks were investigated in which up to 20% of birds exhibited clinical signs of poor growth and "hot foot" syndrome (swollen inflamed footpads). Once an outbreak occurred, chronic infection of the farm usually ensued. Grossly the hocks and footpads were swollen by a purulent exudate and associated inflammatory changes with histological features of a severe acute synovitis. Seroconversion of the flocks occurred at the time of the development of lesions. M. synoviae specific antibodies were demonstrated by ELISA in the joint fluid of affected birds. It is concluded that the cases described are similar to avian infectious synovitis syndrome caused by M. synoviae previously described overseas.     

Leptospira interrogans serovar hardjo is not a major cause of bovine abortion in Victoria

The aim of this study was to determine whether evidence could be obtained of foetal infection with Leptospira interrogans serovar hardjo in aborted foetuses collected from dairy farms. Material from 197 abortions occurring over a wide area of Victoria was collected over 3 years. None of 195 foetal kidney cultures or 7 cultures from membranes was positive for leptospiral organisms. Immunogold silver staining for leptospires was performed on sections of kidneys, lungs or heart from 156 foetuses, with negative results. Evidence of transient leptospiral infection in 11 of 123 foetuses was obtained by foetal heart blood serology. Two isolates of L. interrogans serovar hardjo were obtained from the urine of milking cows. These strains were examined by restriction endonuclease analysis and both were shown to be of the genotype Hardjobovis, as have been all Australian isolates studied so far. It appears that foetal infection with serovar hardjo is not associated with any substantial proportion of bovine abortions in Victoria, in contrast to the situation in Northern Ireland. The apparent absence from Victoria of the pathogenic genotype Hardjoprajitno is a possible explanation.     

A climatological basis for conserving groundwater and reducing overflow in aquaculture ponds in the Southeast United States

Drop-fill water management schemes for aquacultural ponds reduce both groundwater use and effluent release. A drop-fill scheme assumes that pond water level will be allowed to decrease to the “drop” depth before makeup water is used to return it to the “fill” depth, which is typically some fraction (e.g., 1/2) of the drop depth. This paper compares predicted performance of drop-fill schemes at five sites in the Southeast U.S. (Thompsons, TX, Stuttgart, AR, Stoneville, MS, Clemson, SC, and Fairhope, AL). The locations were chosen to assess the effect of the east–west precipitation gradient and the south–north change from maritime to continental characteristics on the drop-fill approach in this region.

Performance of the drop-fill schemes was based on calculated daily water balances for ponds using 40-year (1961–2000) precipitation (P) and evaporation (E) records at the sites. Pond evaporation is assumed to be 0.8 × pan evaporation. Since performance differences based on regional P minus E (P−E) records was the subject of this work, ponds were assumed identical in other respects (i.e., all ponds were assumed to be levee-type and to have zero infiltration).

Simulated drop-fill schemes tested included (in cm): 0/0, 5/2.5, 10/5, 15/7.5, 20/10, 25/12.5, 30/15, 45/22.5, 60/30, 90/45, and 120/60. Each scheme was simulated using daily time steps for 40 years at each site. Results suggested that rigorous adherence to even a modest drop-fill scheme results in substantial reductions in both groundwater use and effluent release. It also appears that P−E conditions at all sites allow implementation of more aggressive drop-fill schemes in properly designed ponds that will require no supplemental groundwater for most years. This was also true with respect to effluent release at three of five sites. At two sites, precipitation was sufficiently large that zero effluent years were either not predicted (Fairhope) or relatively uncommon (Clemson) for any drop-fill scheme.     

Suspected fatal venous air embolism during anaesthesia in a Pomeranian dog with pulmonary calcification

CASE HISTORY: Death occurred in a 1.25 kg, 9-month-old female Pomeranian dog undergoing anaesthesia for surgical repair of partially healed fractures of the radius and ulna.

CLINICAL FINDINGS: Following sedation, anaesthesia was induced using thiopentone and maintained with halothane in oxygen. An acute decrease in the dog's end-tidal carbon dioxide (EtCO₂) measurements was noted approximately 50 min after induction, immediately following delivery of a 5-ml bolus of lactated Ringer's solution (LRS) administered to flush a small (0.06 ml) volume of fentanyl via a pre-placed intravenous (I/V) catheter. Venous air embolism (VAE) was suspected and the dog died despite interventive therapy. On post-mortem examination, several air bubbles were noted when the right ventricle was opened under water. Histologically, the kidneys appeared abnormal with immature glomeruli, and the lungs appeared diffusely mineralised. The origin of the air was probably small bubbles and microbubbles that may have been present in the extension set and 20 ml syringe used for the administration of fentanyl and I/V fluids to the dog.

DIAGNOSIS: Renal dysplasia and diffuse pulmonary calcification, with VAE as the probable cause of death.

CLINICAL RELEVANCE: In this case of VAE-associated anaesthetic death, it is further speculated that underlying pulmonary disease, in the form of pulmonary calcification, may have contributed to an increased sensitivity to the adverse effects of VAE.