The increasing risk of Lyme disease in Canada

There is an increasing risk of Lyme disease in Canada due to range expansion of the tick vector, Ixodes scapularis. The objectives of this article are to i) raise public awareness with the help of veterinarians on the emerging and expanding risk of Lyme disease across Canada, ii) review the key clinical features of Lyme disease in dogs, and iii) provide recommendations for veterinarians on the management of Lyme disease in dogs.     

Update on the 35‐year expansion of the invasive root pathogen,Phytophthora lateralis,across a landscape of Port Orford cedar (Chamaecyparis lawsoniana)

Port Orford cedar (Chamaecyparis lawsoniana) is endemic to northern California and southwestern Oregon and is considered a foundation species that plays critical roles in riparian areas and on nutrient‐poor soils. Since 1952, a non‐native, pathogenic oomycete (Phytophthora lateralis) has been spreading throughout the range of the cedar. Most spread occurs by vehicles carrying infested soil along gravel roads primarily used for timber harvest. In a previous study conducted in 1998 and 1999, Port Orford cedar and P. lateralis were censused in a 37‐km² study area and dendrochronology was used to reconstruct the history of pathogen invasion. That work, which represents the only detailed analysis of spread rates for P. lateralis, showed that the first successful invasion into the study area took place in 1977 and that 43% of the susceptible host sites (stream crossings) were infested by 1999. In the work presented here, all sites that were uninfested in 1999 were re‐censused in 2012, extending the historical reconstruction of P. lateralis spread to 35 years. Two new infestations were initiated between 1999 and 2012, suggesting that the rate of spread of P. lateralis has slowed greatly. Between 1980 and 1989, the average number of new site infestations was 1.8 infestations per year, while between 1990 and 1999 the average was 0.4 infestations per year and between 2000 and 2009 the average was 0.2 infestations per year. Several potential explanations for the reduced number of new infestations are discussed.     

Defining the poor by the rural communities of Burkina Faso: implications for the development of sustainable parkland management

Parklands are mixtures of trees and shrubs that farmers select for certain functions. In the Sahel, parklands are cultivated together with staple food crops, such as millet and sorghum. Parkland trees are sources of foods, including fruits, fats, oils, leafy vegetables, nuts and condiments that complement food crops in the local diet. Despite their socio-economic and ecological role, many studies have shown that the parklands are degrading very rapidly. Therefore, there is a need to undertake restoration actions that are based on a clear understanding of the livelihood context, such as the wealth status of the farmers, in which these agroecosystems are evolving. Thus, we conducted a wealth survey with rural communities in two different farming systems of Burkina Faso that are the cereal-based system in the “Plateau Central” and the cotton-based system in the “Boucle du Mouhoun”. A total of twelve villages were sampled, six villages for each system. The Participatory Analysis of Poverty and Livelihood Dynamics (PAPoLD) method was used by rural farmers to rank farmer households of their communities according to their wealth status. The results revealed that 70% of households in the Plateau Central and 56% in the “Boucle du Mouhoun” managed to escape poverty, and became wealthy. However, 2% of households of the villages in the Plateau Central and 6% in “Boucle du Mouhoun” fell into poverty in the same period whereas 9 and 12% remained poor in these zones, respectively. The main causes associated with households getting out of poverty are subsidies for cotton, external revenues from relatives working in towns and gardening activities. Death of spouse, illness, high number of people in the household and indebtedness are the main causes that lead into poverty. The implications of these findings in designing appropriate policies and management options for a sustainable management of agroforestry parklands under different land use systems were finally discussed.     

Identification of phytotoxins from <Emphasis Type="Italic">Botryosphaeria obtusa</Emphasis>, a pathogen of black dead arm disease of grapevine

A bioassay-guided fractionation of a culture filtrate of Botryosphaeria obtusa led to the isolation of four dihydroisocoumarins, named mellein 1, 4-hydroxymellein 2, 7-hydroxymellein 3 and the new 4,7-dihydroxymellein 4. LC-UV-DAD-MS analysis of vine wood infected by B. obtusa revealed the presence of mellein (1). Botryosphaeria obtusa was also able to oxidise wood δ -resveratrol into the dimer delta-viniferin. The structures of isolated phytotoxins were established on the basis of IR, MS, 1D and 2D NMR.     

Vegetative propagation of twelve fodder tree species indigenous to the Sahel,West Africa

In the Sahel region, many woody species are used as fodder because of their high nitrogen content, especially during the dry season, in contrast to grasses and crop residues. Unfortunately, this resource is being threatened by regular pruning, increasing livestock browsing and impeding their natural regeneration. Therefore, there is a need to find appropriate regeneration options to sustain fodder production. Thus, a series of vegetative propagation experiments were conducted to identify the most appropriate multiplication methods of some of the species used as fodder. This series included testing the effects of naphthalene acetic acid (NAA) and indole butyric acid (IBA) on rooting ability of stem cuttings of 12 species: Afzelia africana, Balanites aegyptiaca, Bauhinia rufescens, Commiphora africana, Faidherbia albida, Ficus gnaphalocarpa, Guiera senegalensis, Kigelia africana, Pterocarpus erinaceus, Pterocarpus lucens, Pterocarpus santalinoides and Terminalia avicennioides. The series also evaluated the impacts of the size (C. africana) and the age (P. erinaceus) of the cuttings on their rooting success. Pterocarpus santalinoides was revealed to be an easy-to-root species, showing a high percentage of rooted cuttings (up to 88±3%), followed by P. erinaceus, P. lucens and B. aegyptiaca (up to 37±4%, 31±5% and 26±6%, respectively), in contrast to A. africana, cuttings of which did not root at all. The application of NAA and IBA enhanced the number of roots and secondary roots per rooted cutting. Large-diameter cuttings (15–20?mm) of deeply planted C. africana gave the highest percentage of rooted cuttings (78.3±4.4%). Tree pruning improved the rooting capacity of cuttings collected from P. erinaceus with one-month resprouts giving the highest percentage of rooted cuttings (50.0±6.7%). These results indicate that P. santalinoides, C. africana, P. erinaceus, P. lucens and B. aegyptiaca are amenable to vegetative propagation as an alternative to sexual propagation.     

Stable recombinant alpaca antibodies for detection of Tulip virus X

For detection of the plant pathogenic Tulip virus X (TuVX), a panel of six recombinant antibodies was identified. To this end, a repertoire of variable domains from heavy-chain immunoglobulins (VHH) was cloned from an alpaca, which had been immunized with TuVX. Binding domains were selected by phage display and panning on immobilized TuVX particles. Recombinant VHH antibodies were tested for sensitivity in a sandwich ELISA, and were demonstrated to be readily able to distinguish TuVX-infected tulip leaf material from uninfected leafs. No cross-reactivity of the VHH antibodies to related flexiviridae was observed. Recombinant VHHs maintained their reactivity upon storage at −20°C for over a year. The effect of incubation at higher temperatures for prolonged time was studied. Two out of three VHH proteins retained activity after several weeks of storage at 37°C.     

"霉菌毒素全球流行情况及其预防措施"专栏(五)霉菌毒素的终极武器——免疫系统

霉菌毒素是家禽健康和生产的一个主要威胁,由于这些毒素具有特殊的化学特性,要建立从饲料原料中清除毒素的控制体系并非是一件容易的事.减少霉菌毒素对动物的危害需从以下两方面人手:一是降低霉菌毒素污染动物饲料的风险及水平.二是降低饲料中残留毒素对动物的危害.