Prevention of renal carriage of leptospirosis in dogs by vaccination

Dogs vaccinated with a Leptospira interrogans vaccine containing serogroups Canicola and Icterohaemorrhagiae and prepared from cultures grown in a protein-free medium resisted challenge with heterologous representatives of these serogroups. In contrast, control dogs were pyrexic and leptospires were isolated from the blood for nine days following Canicola challenge and six days after Icterohaemorrhagiae challenge. Leptospires were isolated from the urine of controls throughout the post challenge period and from kidneys at post mortem examination of six out of six and four out of six Canicola and Icterohaemorrhagiae challenged controls, respectively. There have been no reports of hypersensitivity reactions to this vaccine since its introduction in 1980.     

Ergovaline does not alter the severity of ryegrass staggers induced by lolitrem B

AIM: To investigate a possible interaction between lolitrem B and ergovaline by comparing the incidence and severity of ryegrass staggers in sheep grazing ryegrass (Lolium perenne) containing lolitrem B or ryegrass containing both lolitrem B and ergovaline.

METHODS: Ninety lambs, aged approximately 6 months, were grazed on plots of perennial ryegrass infected with either AR98 endophyte (containing lolitrem B), standard endophyte (containing lolitrem B and ergovaline) or no endophyte, for up to 42 days from 2 February 2010. Ten lambs were grazed on three replicate plots per cultivar. Herbage samples were collected for alkaloid analysis and lambs were scored for ryegrass staggers (scores from 0–5) weekly during the study. Any animal which was scored ≥4 was removed from the study.

RESULTS: Concentrations of lolitrem B did not differ between AR98 and standard endophyte-infected pastures during the study period (p=0.26), and ergovaline was present only in standard endophyte pastures. Ryegrass staggers was observed in sheep grazing both the AR98 and standard endophyte plots, with median scores increasing in the third week of the study. Prior to the end of the 42-day grazing period, 22 and 17 animals were removed from the standard endophyte and AR98 plots, respectively, because their staggers scores were ≥4. The cumulative probability of lambs having scores ≥4 did not differ between animals grazing the two pasture types (p=0.41).

CONCLUSIONS AND CLINICAL RELEVANCE: There was no evidence for ergovaline increasing the severity of ryegrass staggers induced by lolitrem B. In situations where the severity of ryegrass staggers appears to be greater than that predicted on the basis of concentrations of lolitrem B, the presence of other tremorgenic alkaloids should be investigated.     

Blood, Bull Terriers and Babesiosis: further evidence for direct transmission of Babesia gibsoni in dogs

This study reports on the epidemiology of Babesia gibsoni in American Pit Bull Terriers living in a region of western Victoria in southern Australia. Both American Pit Bull Terriers (n = 100) and other dog breeds (n = 51) were screened for B gibsoni using immunofluorescent antibody testing (IFAT) and/or polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). A questionnaire was also completed by each dog owner, ascertaining the husbandry and habits of the dogs sampled. Fourteen dogs were positive for B gibsoni using IFAT and/or PCR-RFLP and all were American Pit Bull Terriers. Dogs that were male and/or had been bitten by or were biters of other American Pit Bull Terriers were more likely to be B gibsoni positive, thus suggesting that blood-to-blood transmission contributes to the spread of this disease between dogs.     

A Comparison of Three Methods of Pike (Esox lucius L.) Removal from a Lowland Trout Fishery

The seine netting, gill netting and angling techniques used at Grafham Water for the removal of pike are described and assessed, and the effectiveness of the various methods compared. It was found that a combination of summer gill netting and seine netting was most effective, but it was concluded that angling was worthwhile during the autumn months.     

Rhizobia in tropical legumes—XIV. Ion uptake differences between fast- and slow-growing strains

We compared the uptake of nitrogen, potassium and phosphorus (as well as ¹⁴C-labelled mannitol, ³H-labelled glutamate, and ³²P-labelled phosphate) in three fast- and three slow-growing rhizobia. The fast-growing strains used were Rhizobium meliloti (isolated from Medicago sativa), R. trifolii (from Trifolium subterraneum), and Rhizobium spp from Leucaena leucocephala, while the slow-growing strains were R. japonicum (Glycine max), and two Rhizobium spp (from Centrosema pubescens and Crotolaria anagyroides). Slow-growing organisms preferentially utilized glutamate in the medium. Both fast- and slow-growing strains took up more NH⁺₄-N than NO^?₃-N on a per cell basis. In the presence of mannitol, fast-growing strains can cause either acid or alkaline reactions, an effect that is dependent only on the N-source (NH⁺₄ or NO^?₃). Uptake preferences of the fast-growing Leucaena isolate (UMKL 19) resembled those of the slow-growing rhizobia, further strengthening the argument that this organism (and others like it) may be intermediate between the normal fast- and slow-growing groups. Generally, the efficiency of uptake of N (either as NH⁺₄ or NO^?₃), P, and therefore K, was greater in the fast-growing organisms.     

Akabane disease in sheep

Perinatal lamb mortality, associated with malformations of the CNS due to Akabane viral infection, occurred in 4 of 9 flocks of ewes lambing on 3 farms between 26 May and 14 November, 1976. Cases were restricted to ewes conceiving prior to the second week of March and lambing between 26 May and 19 July. As judged by seroconversion in sentinel flocks on 2 of the farms, field infection with Akabane virus occurred mainly between mid-February and mid-April. Malformations of the CNS occurred in 42.5%, 51.2%, 100% and 31.0% of the dead lambs examined in the affected flocks respectively. Prevalence in the 4 affected flocks, expressed as the proportion of ewes lambing which delivered at least one malformed foetus, was 6.1%, 8.4%, 88.9% and 5.7% respectively. Lamb mortality due to malformations of the CNS was 7.1%, 5.5%, 92.3% and 5.7% of lambs born. Age-specific prevalence was calculated for 3 of the 4 flocks and 2-year-old ewes accounted for 71.4% and 76.9% of total cases respectively in 2 flocks, whereas in one flock malformations occurred at equivalent frequencies throughout several older age groups. Birthweights of affected lambs were usually significantly lighter than those of unaffected lambs of similar sex and birth-type, and their mean duration of gestation was slightly, and significantly, prolonged. Micrencephaly (88.1% of cases) and hydrocephalus (68.7% of cases) were the outstanding pathological features of the malformations with hydranencephaly, microgyria, porencephaly and attenuation of the spinal cord occurring at much lower frequencies.(ABSTRACT TRUNCATED AT 250 WORDS)     

Rhizobia in tropical legumes—XIII. Biochemical basis of acid and alkali reactions

Three fast-growing rhizobia (Rhizobium meliloti isolated from Medicago saliva, R. trifolii from Trifolium subterraneum, and Rhizohium sp. from Leucaena leucocephala) and three slow-growing rhizobia R. japonicum from Glycine max, Rhizobium spp from Centrosema pubescens and Crotolaria anagyroides) were grown in defined media. The mean generation times of the fast-growing and slowgrowing strains were 3.8 h and 8.6 h respectively. Slow-growing organisms raised the initial pH of the defined medium while the fast-growing organisms lowered it. Rates of oxygen consumption tended to be higher in the slow-growing organisms.UMKL 19 (isolated from L. leucocephala) possessed all the normal reactions of fast-growing rhizobia but had a single sub-polar flagellum, similar to the three slow-growing strains studied.Certain combinations of amino acids and sugars (e.g. glutamine and galactose) induced an acidic reaction in the fast-growing organisms while the slow-growing ones changed the media to alkaline. Fast-growing organisms utilized more galactose for growth compared to slow-growing ones. Both types of organisms synthesized and released a wide range of amino acids into the medium.We suggest that pH changes produced by rhizobia growing on yeast-extract mannitol media are caused by the preferential utilization of sugars by fast-growing organisms and nitrogenous compounds by slow-growing ones.