Detection of the Togninia Teleomorph of Phaeoacremonium aleophilum in Australia

Moist incubation of grapevine wood infected with both Phaeoacremonium aleophilum and Phaeomoniella chlamydospora yielded an ascomycete referable to the genus Togninia (Ascomycota, Calosphaeriales). Single ascospore cultures were morphologically identical to Pm. aleophilum. The rDNA ITS sequence of single ascospore isolates was identical to published sequences for the majority of Pm. aleophilum isolates. Comparison with the morphology of other wood staining Togninia species confirms that the teleomorph of Pm. aleophilum is Togninia minima

Quantitative Assessment of the Risk of Release of Foot-and-Mouth Disease Virus via Export of Bull Semen from Israel

Various foot-and-mouth disease (FMD) virus strains circulate in the Middle East, causing frequent episodes of FMD outbreaks among Israeli livestock. Since the virus is highly resistant in semen, artificial insemination with contaminated bull semen may lead to the infection of the receiver cow. As a non-FMD-free country with vaccination, Israel is currently engaged in trading bull semen only with countries of the same status. The purpose of this study was to assess the risk of release of FMD virus through export of bull semen in order to estimate the risk for FMD-free countries considering purchasing Israeli bull semen. A stochastic risk assessment model was used to estimate this risk, defined as the annual likelihood of exporting at least one ejaculate of bull semen contaminated with viable FMD virus. A total of 45 scenarios were assessed to account for uncertainty and variability around specific parameter estimates and to evaluate the effect of various mitigation measures, such as performing a preexport test on semen ejaculates. Under the most plausible scenario, the annual likelihood of exporting bull semen contaminated with FMD virus had a median of 1.3 * 10(-7) for an export of 100 ejaculates per year. This corresponds to one infected ejaculate exported every 7 million years. Under the worst-case scenario, the median of the risk rose to 7.9 * 10(-5), which is equivalent to the export of one infected ejaculate every 12,000 years. Sensitivity analysis indicated that the most influential parameter is the probability of viral excretion in infected bulls

Taxonomy and pathology of Togninia (Diaporthales) and its Phaeoacremonium anamorphs.

The genus Togninia (Diaporthales, Togniniaceae) is here monographed along with its Phaeoacremonium (Pm.) anamorphs. Ten species of Togninia and 22 species of Phaeoacremonium are treated. Several new species of Togninia (T.) are described, namely T. argentinensis (anamorph Pm. argentinense), T. austroafricana (anamorph Pm. austroafricanum), T. krajdenii, T. parasitica, T. rubrigena and T. viticola. New species of Phaeoacremonium include Pm. novae-zealandiae (teleomorph T. novae-zealandiae), Pm. iranianum, Pm. sphinctrophorum and Pm. theobromatis. Species can be identified based on their cultural and morphological characters, supported by DNA data derived from partial sequences of the actin and ß-tubulin genes. Phylogenies of the SSU and LSU rRNA genes were used to determine whether Togninia has more affinity with the Calosphaeriales or the Diaporthales. The results confirmed that Togninia had a higher affinity to the Diaporthales than the Calosphaeriales. Examination of type specimens revealed that T. cornicola, T. vasculosa, T. rhododendri, T. minima var. timidula and T. villosa, were not members of Togninia. The new combinations Calosphaeria cornicola, Calosphaeria rhododendri, Calosphaeria transversa, Calosphaeria tumidula, Calosphaeria vasculosa and Jattaea villosa are proposed. Species of Phaeoacremonium are known vascular plant pathogens causing wilting and dieback of woody plants. The most prominent diseases in which they are involved are Petri disease and esca, which occur on grapevines and are caused by a complex of fungi, often including multiple species of Phaeoacremonium. Various Phaeoacremonium species are opportunistic fungi on humans and cause phaeohyphomycosis. The correct and rapid identification of Phaeoacremonium species is important to facilitate the understanding of their involvement in plant as well as human disease. A rapid identification method was developed for the 22 species of Phaeacremonium. It involved the use of 23 species-specific primers, including 20 primers targeting the ß-tubulin gene and three targeting the actin gene. These primers can be used in 14 multiplex reactions. Additionally, a multiple-entry electronic key based on morphological, cultural and ß-tubulin sequence data was developed to facilitate phenotypic and sequence-based species identification of the different Phaeoacremonium species. Separate dichotomous keys are provided for the identification of the Togninia and Phaeoacremonium species. Keys for the identification of Phaeoacremonium-like fungi and the genera related to Togninia are also provided. The mating strategy of several Togninia species was investigated with ascospores obtained from fertile perithecia produced in vitro. Togninia argentinensis and T. novae-zealandiae have homothallic mating systems, whereas T. austroafricana, T. krajdenii, T. minima, T. parasitica, T. rubrigena and T. viticola were heterothallic.

The Risk of Foot and Mouth Disease Transmission Posed by Public Access to the Countryside During an Outbreak

During the 2001 UK FMD outbreak, local authorities restricted rural access to try to prevent further disease spread by people and animals, which had major socio-economic consequences for rural communities. This study describes the results of qualitative veterinary risk assessments to assess the likelihood of different recreational activities causing new outbreaks of foot and mouth disease, as part of contingency planning for future outbreaks. For most activities, the likelihood of causing new outbreaks of foot and mouth disease is considered to vary from very low to medium depending on the control zone (which is based on distance to the nearest infected premises), assuming compliance with specified mitigation strategies. The likelihood of new outbreaks associated with hunting, shooting, stalking, and equestrian activities is considered to be greater. There are areas of significant uncertainty associated with data paucity, particularly regarding the likelihood of transmission via fomites. This study provides scientific evidence to underpin refinement of rural access management plans and inform decision-making in future disease outbreaks

Developments in Grapevine Trunk Diseases Research in Australia

In Australia, trunk diseases of grapevines are becoming increasingly important. Phaeoacremonium chlamydosporum causes black goo decline and is very common in newly planted vineyards in which establishment is slow and uneven. It is apparently introduced to these vineyards as infections of the propagating material. We have isolated the fungus many times from rootstock mother vines and speculate that it spreads from the trunk of the mother vine to the canes which are later harvested as cuttings. Histological studies of inoculated vine shoots in tissue culture, show that the fungus infects the xylem parenchyma cells as intracellular hyphae, and these cells produce tyloses in the adjacent xylem vessels. The hyphae also penetrate the vessels, often by way of the tyloses. Brown deposits (black goo) are seen in vessels and cells, often some distance from active hyphae. Phaeoacremonium chlamydosporum has also been found to produce pycnidia on the surfaces of infected wood when moist incubated. The same pycnidia were also found on the surfaces of inoculated tissue culture vines, proving that they are pycnidia of P. chlamydosporum. The spores produced by the pycnidia appear to be conidial rather than spermatial as they germinate readily on agar and develop normal colonies. Esca was formally diagnosed for the first time in Australia in 1999, although it is believed to have been present for many years. In addition to Phellinus (Fomitiporia) punctatus, we have also found a second species of Phellinus associated with similar symptoms. This species differs from P. punctatus in the production of setae on host tissue and in culture. Like P. punctatus it has a close association with Phaeoacremonium chlamydosporum. Eutypa dieback appears to be increasing in severity in Australian vineyards and may be a major limiting factor in the sustainability of Australian wine production. A national trunk disease project has commenced to develop management strategies for black goo decline, esca, Eutypa dieback and other trunk diseases