A blind test of the serological response of dogs to infection with Taenia ovis

Fifty six dogs of mixed age and sex were acquired from farms in the Otago/Southland region, and maintained at the Hydatid Research Unit, Taieri, where 43 were each fed two Tueniu ovis cysts. All were bled fortnightly for six or 12 weeks. Coded sera were sent to Wallaceville Animal Research Centre for testing using ELISA, with antigen from T. ovis scoleces. Dog treatments were identified after all tests were complete. A discriminant level was derived from the mean absorbance value plus three standard deviations of 56 sera taken at time zero and 78 sera from serially bled uninfected dogs. None of these 134 sera registered as a false positive using this discriminant level. The data showed no significant deviation from normality, and the expected frequency of the occurrence of false positives is therefore less than 0.14%. Four weeks after infection 63% of dogs proved to be infected were serologically positive, rising to 78% after 6 weeks. When worms were removed by anthelmintic treatment, ELISA absorbance levels decreased. Four weeks after removal 70% of previously infected dogs remained positive, decreasing to 30% after 6 weeks. Six weeks after infection the sensitivity of the test was 78%, and the specificity 63%. However, if dogs with positive ELISA absorbance levels, but which did not purge worms, were regarded as having had worms, the respective figures would be 82% and 100%. The latter figures are similar to our previously published laboratory results. The test is of comparable efficiency to arecoline purgation for surveillance, and has the additional advantage of detecting infection in the majority of those dogs that have been infected for three weeks or more but fail to pass worms on purgation, and a substantial proportion of those infected dogs that were treated by their owners prior to presenting them for purgation in order to avoid detection of infection.     

Outbreak of cucumber mosaic virus on musa sp. in Tamil Nadu,India

Cucumber Mosaic Virus, or Infectious Chlorosis, was found in alarming proportions in all the districts of Tamil Nadu on the ‘Robusta’ (Dwarf Cavendish) and ‘Poovan’ (Mysore) cultivais. The disease was transmitted only through suckers from the diseased gardens. Among the genotypes screened, the clones with ABB genomes showed complete field resistance.     

Effect of canopy cover,seeding depth,and soil moisture on emergence of Centaurea maculosa and C. diffusa*

The effects of canopy cover, seeding depth, and soil moisture on emergence of Centaurea maculosa Lam. and C. diffusa Lam. were studied. Canopy cover had no effect on ermergence rate (seedlings/day/100 seeds) of either species. Seeds of both species emerged faster when placed on the soil surface. Emergence rate decreased as seeding depth increased. Both species required more than 55% initial soil moisture to initiate emergence, with 65–70% being optimum. Percentage emergence followed exactly the same trend as emergence rate. C. maculosa had better emergence characteristics over a wider range of conditions than C. diffusa, possibly being some of the reasons for the former having a wider geographical distribution in the United States and Canada.     

Fuels from biomass: integration with food and materials systems

The development of fuels from biomass can lead naturally to dispersed facilities that incorporate food or materials production (or both) with fuel production, forming adaptive systems that can be modified to meet evolving needs and constraints. The technology that is appropriate to each system needs to be worked out, taking into account associated food and materials opportunities in order to decrease the ultimate cost of energy delivered to the consumer. I analyze possible systems based on sugarcane, corn, and guayule.     

Stability of abdominal fat and meat of broilers: Effect of duration of feeding antioxidants 1

1. The α‐tocopherol (AT) content of abdominal fat and fat stability increased as a function of the duration of α‐tocopheryl acetate (ATA) feeding in broilers fed on diets containing either 40 g acidulated soyabean‐oil soapstock (ASS) or tallow/kg. A linear relationship was observed between AT content of the adipose tissue and its stability with both types of fat supplements.

2. The stabilities of carcass fat and meat of 9‐week‐old broilers fed on diets containing ASS with 300 mg ethoxyquin (EQ)/kg or diets containing tallow with 20 mg ATA/kg from weeks 5 to 9 were comparable with those obtained by feeding these antioxidants and fats throughout the growth period.

3. ATA added to a diet containing ASS, and EQ, added to a diet containing tallow did not improve meat stability despite such an effect on adipose tissue when fed for 9 weeks. The results emphasise the importance of using the dietary antioxidant appropriate to the fat supplement to improve carcass stability.     

The effects of ultraviolet-B (UV-B: 290–320 nm) radiation on blister blight disease of tea (Camellia sinensis)

Sunlight is known to reduce the incidence of blister blight disease of tea, caused by Exobasidium vexans . The effects of the ultraviolet-B (UV-B: 290–320 nm) component of solar radiation on the disease and the development of E. vexans were studied in the field in Sri Lanka using UV-screening filter materials held over a commercial crop. Exclusion of UV-B radiation by Polyester, which reduces fluxes in the UV-B region by approximately 75–85%, increased both the number of translucent spots (immature sites of infection) and number of sporulating blisters (mature sites of infection), but it had little or no effect on the sporulation of the pathogen. When basidiospores were artificially inoculated on leaves, and were exposed to full or filtered solar radiation, their survival and germination increased when UV-B wavelengths were removed; significant differences were found 62 h after inoculation. However, UV-B did not affect the extension of germ tubes. This study indicates that the UV-B component of solar radiation plays an important role in the natural regulation of blister blight disease in the field.