Treatment and control by vaccination of erysipelas in farmed emus (Dromaius novo-hollandiae)

Objective To study erysipelas in farmed emus and the treatment and control of the disease by vaccination.
Design A retrospective study of field outbreaks in emus and challenge experiments in mice using field and vaccine strains of the organism.
Procedure Outbreaks of the disease were described. Field strains of the organism were identified and tested by challenge experiments in mice against commercial vaccine strains.
Results Erysipelas was characterised by sudden death in yearling emus. Deaths mainly occurred during the cold wet months. Mortalities of 6 to 10% were seen within the first 7 to 10 days of an outbreak. Clinical signs were uncommon but some birds exhibited lethargy and greenish diarrhoea. Necropsy findings included marked petechial haemorrhages on the serosal surface of the large intestine in particular, pericardial effusion and congestion and mottling of the liver. Treatment consisted of individual or mass medication with procaine penicillin, reduction of stress factors such as overcrowding, and spelling and rotation of paddocks. Isolates from two field outbreaks were identified as strain 21. Complete protection was provided by a commercial strain 2b vaccine against challenge by strain 21 field isolates in mice. Annual vaccination of birds at 4 weeks and again at 8 weeks of age appeared to control further outbreaks on farms where the disease had previously occurred and vaccination appeared to protect for at least 12 months.
Conclusion Treatment of birds with antibiotics may be feasible in the face of an outbreak. However, annual vaccination of birds with an appropriate vaccine is recommended.     

Effects of residues of deltamethrin in cattle faeces on the development and survival of three species of dungbreeding insect

Objective To assess the toxicity to insects of drug residues excreted in cattle faeces following treatment with deltamethrin.
Design Bioassays were performed on one species of dung-breeding fly ( Musca vetustissima ) and two species of dung beetle ( Onthophagus binodis and Euoniticellus fulvus ).
Animals Cattle on properties near Kangaroo Valley, Canberra and Gundagai were treated with pour-on formulations of deltamethrin. Untreated animals acted as controls.
Procedures Faeces from treated and untreated cattle were inoculated with newly emerged fly larvae or fed to adults of two species of dung beetle. Percentage survival and duration of development provided measures of the toxicity of deltamethrin residues in faeces.
Results Residues of deltamethrin were excreted in concentrations sufficient to inhibit survival of larvae of M vetustissima for 1 to 2 weeks after treatment. Peak concentrations of 0.4mg deltamethrin/kg dry weight of faeces occurred 3 days after treatment and were sufficient to kill adult beetles for at least twice this period. With one of two formulations tested, there was evidence of a reduction in dung beetle fecundity and an increase in the duration of juvenile development. A model of the effect of deltamethrin on the breeding success of dung beetles in the field suggests that a single treatment, applied when most of the population is in a non-parous condition, may cause up to 75% reduction in beetle acitivity by the end of the season. Multiple treatments at 10 or 21 day intervals may drive local populations towards extinction.
Conclusion Depending on the time and frequency of treatment, the effect of deltamethrin on insects in cattle faeces may range from negligible to catastrophic.     

Widespread iron limitation of phytoplankton in the south pacific ocean

Diel fluorescence patterns were discovered in phytoplankton sampled over 7000 kilometers of the South Pacific Ocean that appear indicative of iron-limiting growth conditions. These patterns were rapidly lost after in situ iron enrichment and were not observed during a 15,000-kilometer transect in the Atlantic Ocean where iron concentrations are relatively high. Laboratory studies of marine Synechococcus sp. indicated that the patterns in the South Pacific are a unique manifestation of iron limitation on the fluorescence signature of state transitions. Results suggest that primary productivity is iron limited not only throughout the equatorial Pacific but also over much of the vast South Pacific gyre.     

The molecular epidemiology of equine herpesvirus 1 (equine abortion virus) in Australasia 1975 to 1989

The restriction endonuclease DNA fingerprints of 57 isolates of equine herpesvirus 1 (EHV1; equine abortion virus) from abortion, perinatal foal mortalities and encephalitis from 15 epidemics that occurred in Australasia between 1975 and 1989 were examined using the enzymes Bam HI, EcoRI and Bgl II. There was a remarkable degree of uniformity in the restriction patterns; mobility differences were observed in only 14 of 52 (27%) of the fragments. Twelve of these 14 fragments were located within the repeat structures that bracket the unique short region of the genome or were located at the left terminus of the 150 kilobase pair genome. Based on the Bam HI fingerprints the commonest virus identified in our study was EHV1.IP (P is for prototype strain). There was a single notable exception in that the Bam HI fingerprints of all 8 isolates from one of 3 Victorian farms that experienced abortion in 1989 resembled a variant EHV1.IB that was identified as a cause of abortion in Central Kentucky in 1970 to 1974. We present evidence that EHV1.IB caused abortion in California in 1964 and has remained unaltered in its Bam HI restriction pattern. No antigenic differences were found among 4 distantly related EHV1 isolates, including the variant IB, using a panel of 5 monoclonal antibodies to glycoprotein C (gC), a glycoprotein recognised to be highly variable. The uniformity of these unrelated EHV1 isolates is further evidence for a recent origin for EHV1 and may help to explain the natural history of this virus in the horse in which it seems to be a cause of serious epidemics of abortion and perinatal mortality, and less commonly of encephalitis.