Pyrrolizidine alkaloidosis of cattle associated with Senecio lautu

Summary Serious incidents of pyrrolizidine alkaloidosis of cattle in 10 herds exposed to the Australian native plant, Senecio lautus (Asteraceae), were seen in central Queensland during 1988–1992. The deaths of 226 cattle were recorded. A mean of 8% of cattle died in affected groups (range 2 to 58%). Sickness and deaths usually occurred some months after access to S lautus. Typically, affected cattle lost body condition to the point of emaciation before dying and had persistent diarrhoea. Some animals developed abnormal behaviour and died after a shorter illness. Liver specimens from affected cattle in all herds contained lesions consistent with pyrrolizidine alkaloidosis. Thin layer chromatography of extracts of blood and liver samples from cattle from 5 herds detected pyrrolic metabolites. The identity of these was confirmed by mass spectroscopy on samples from one herd. Unseasonal autumn and winter rain after a dry summer appeared to favour growth of S lautus at the expense of other pasture species. A subsequent dry period promoted consumption of S lautus and was followed by a cluster of poisoning incidents.     

Spatiotemporal variation in the fungal community associated with wheat leaves showing symptoms similar to stagonospora nodorum blotch

The fungal communities on wheat leaves showing symptoms similar to stagonospora nodorum blotch were analysed using terminal restriction fragment length polymorphism (T-RFLP). Collection of diseased leaves was carried out in eleven winter wheat fields located in three regions of Sweden during mid-July in 2003–2005. Fourteen different fungal species were found on the leaves out of which thirteen were identified to the species level and one to the genus level. The majority of the samples had between one and four species present of which at least one was a pathogen. Among the analysed leaves three major leaf pathogens were found: Phaeosphaeria nodorum was common during 2003 and 2004, Mycosphaerella graminicola dominated during 2005. Pyrenophora tritici-repentis was present in all fields, but sometimes in just a few samples. Phaeosphaeria nodorum and P. tritici-repentis often co-occurred on the same leaf. In addition, seven species of yeast and three saprophytes frequently occurred on the leaves every year. The variation in fungal community was largest between the different years while the region of Uppland diverged from the other two regions in species composition. No significant differences in fungal communities were found within a single field, indicating a uniform community at the lowest spatial level.     

Parascaris equorum in foals and in their environment on a Swedish stud farm, with notes on treatment failure of ivermectin

Environmental contamination and the egg excretion pattern of the ascarid Parascaris equorum (Nematoda) was investigated in relation to anthelmintic treatment on a Swedish stud farm. Faecal samples from 15 foals, dewormed every 8th-week with a paste formulation of ivermectin at the standard dose rate of 0.2 mg/kg bodyweight, were collected at five sampling occasions between August and November 2006. In addition, soil samples were obtained from four paddocks used by these foals in November 2006. The number of eggs per gram (epg) was counted in both faeces and soil. Egg excretion started when the foals were 3-4 months, and reached the highest levels when they were approximately 5-month-old, and was then followed by a decline. Egg excretion seemed to be unaffected by ivermectin despite these foals were dewormed at regular intervals. In four out of five foals examined 10 days after treatment, epg actually increased. In contrast, when either fenbendazol or pyrantel embonate were used instead of ivermectin, treatments were effective. The number of eggs in soil was significantly higher in the permanent paddock compared to in the temporarily used soil paddock and in the summer paddocks.     

Informal value chain actors’ knowledge and perceptions about zoonotic diseases and biosecurity in Kenya and the importance for food safety and public health

Zoonotic diseases, transmitted from animals to humans, are a public health challenge in developing countries. Livestock value chain actors have an important role to play as the first line of defence in safeguarding public health. However, although the livelihood and economic impacts of zoonoses are widely known, adoption of biosecurity measures aimed at preventing zoonoses is low, particularly among actors in informal livestock value chains in low and middle-income countries. The main objective of this study was to investigate knowledge of zoonoses and adoption of biosecurity measures by livestock and milk value chain actors in Bura, Tana River County, in Kenya, where cattle, camels, sheep and goats are the main livestock kept. The study utilised a mixed methods approach, with a questionnaire survey administered to 154 value chain actors. Additional information was elicited through key informant interviews and participatory methods with relevant stakeholders outside the value chain. Our results found low levels of knowledge of zoonoses and low levels of adherence to food safety standards, with only 37% of milk traders knowing about brucellosis, in spite of a sero-prevalence of 9% in the small ruminants tested in this study, and no slaughterhouse worker knew about Q fever. Actors had little formal education (between 0 and 10%) and lacked training in food safety and biosecurity measures. Adoption of biosecurity measures by value chain actors was very low or non-existent, with only 11% of butchers wearing gloves. There was a gendered dimension, evidenced by markedly different participation in value chains and lower adoption rates and knowledge levels among female actors. Finally, cultural and religious practices were shown to play an important role in exposure and transmission of diseases, influencing perceptions and attitudes to risks and adoption of biosecurity measures.     

Calcium concentrations of soil affect suppressiveness against Aphanomyces root rot of pea

The potential for field soils to cause Aphanomyces root rot of pea (Pisum sativum) was estimated for a large number of samples from commercial pea fields over a period of 5 years, using a greenhouse bioassay. The aim of the research project was to gain a mechanistic understanding of soil suppressiveness to the disease. Regression analysis showed that of the measured soil variables (Ca, Mg, K, P, pH), soil Ca concentrations had the strongest (negative) correlation with disease prevalence, and also a significant negative correlation with disease severity in samples with confirmed presence of the disease. Greenhouse bioassays using a set of non-infested soils inoculated with artificially produced oospore inoculum of the casual organism Aphanomyces euteiches, showed a similar negative correlation between soil Ca content and disease severity. Disease severity was not consistently affected by soil sterilisation, but was lowered by the addition of two different Ca salts. In contrast, addition of sodium bicarbonate to two soils lowered the content of water-soluble Ca in the soils and increased disease severity. Studies of cultures of A. euteiches exposed to varying Ca concentrations in vitro showed that zoospore production was inhibited at submillimolar concentrations, while mycelial growth was stimulated or unaffected. We conclude that free Ca is a major variable controlling the degree of soil suppressiveness against A. euteiches, and that inhibition of zoospore production from oospores is a possible mechanism.     

替米考星对仔猪呼吸道感染的疗效试验

进行了替米考星对仔猪呼吸道感染的疗效试验,并与泰乐菌素、支炎净、氟苯尼考、克林霉素进行比较。替米考星治疗组仔猪死亡率、有效率、治愈率分别为5.88%、94.12%和88.23%,经统计学分析,效果显著优于对照组(P<0.01);替米考星预防组仔猪发病率、死亡率、有效率和15 d增重分别为4.76%、0、100%和(5.65±1.25)kg,经统计学分析,有效率、治愈率和相对增重显著高于对照组(P<0.01),仔猪发病率、死亡率明显低于对照组(P<0.01)。试验结果表明,替米考星对仔猪呼吸道感染疗效显著,具有临床使用和推广价值。