Rapid Global Expansion of the Fungal Disease Chytridiomycosis into Declining and Healthy Amphibian Populations.

The fungal disease chytridiomycosis, caused by Batrachochytrium dendrobatidis, is enigmatic because it occurs globally in both declining and apparently healthy (non-declining) amphibian populations. This distribution has fueled debate concerning whether, in sites where it has recently been found, the pathogen was introduced or is endemic. In this study, we addressed the molecular population genetics of a global collection of fungal strains from both declining and healthy amphibian populations using DNA sequence variation from 17 nuclear loci and a large fragment from the mitochondrial genome. We found a low rate of DNA polymorphism, with only two sequence alleles detected at each locus, but a high diversity of diploid genotypes. Half of the loci displayed an excess of heterozygous genotypes, consistent with a primarily clonal mode of reproduction. Despite the absence of obvious sex, genotypic diversity was high (44 unique genotypes out of 59 strains). We provide evidence that the observed genotypic variation can be generated by loss of heterozygosity through mitotic recombination. One strain isolated from a bullfrog possessed as much allelic diversity as the entire global sample, suggesting the current epidemic can be traced back to the outbreak of a single clonal lineage. These data are consistent with the current chytridiomycosis epidemic resulting from a novel pathogen undergoing a rapid and recent range expansion. The widespread occurrence of the same lineage in both healthy and declining populations suggests that the outcome of the disease is contingent on environmental factors and host resistance.

Abacá mosaic virus: a distinct strain of Sugarcane mosaic virus

Abacá mosaic virus (AbaMV) is related to members of the sugarcane mosaic virus subgroup of the genus Potyvirus. The ~2 kb 3′ terminal region of the viral genome was sequenced and, in all areas analysed, found to be most similar to Sugarcane mosaic virus (SCMV) and distinct from Johnsongrass mosaic virus (JGMV), Maize dwarf mosaic virus (MDMV) and Sorghum mosaic virus (SrMV). Cladograms of the 3′ terminal region of the NIb protein, the coat protein core and the 3′ untranslated region showed that AbaMV clustered with SCMV, which was a distinct clade and separate from JGMV, MDMV and SrMV. The N-terminal region of the AbaMV coat protein had a unique amino acid repeat motif different from those previously published for other strains of SCMV. The first experimental transmission of AbaMV from abacá (Musa textilis) to banana (Musa sp.), using the aphid vectors Rhopalosiphum maidis and Aphis gossypii, is reported. Polyclonal antisera for the detection of AbaMV in western blot assays and ELISA were prepared from recombinant coat protein expressed in E. coli. A reverse transcriptase PCR diagnostic assay, with microtitre plate colourimetric detection, was developed to discriminate between AbaMV and Banana bract mosaic virus, another Musa-infecting potyvirus. Sequence data, host reactions and serological relationships indicate that AbaMV should be considered a distinct strain of SCMV, and the strain designation SCMV-Ab is suggested.

Mycotoxins and Fungal Damage in Maize Harvested during 1982 in Far North Queensland

A survey for mycotoxins and fungal damage in maize (Zea mays L.) grown during 1982 in Far North Queensland is reported. This season had a rainfall distribution which was typical for the reglon. The 293 samples examined came from 11 1 farms in eight maize-growing districts. The samples were first subjected to rapid screening tests for fungal damage. Aflatoxins B1, B2, G1, G2 ochratoxin A, T-2 toxin, and sterigmatocystin were not detected, but zearalenone was found in 85% of the samples. The concentrations of zearalenone were correlated with the extent of Gibberella zeae cob rot as indicated by the proportion (up to 2%) of kernels in each sample having a reddish-purple discoloration. In four samples the zearalenone concentration exceeded 1 mg kg-1, but the mean ¦ s.d. (n = 293) concentration in all samples was 0.17 ¦ 0.225 mg kg-1. Concentrations were highest in districts with the highest rainfall during the period of maize growth.

First records of the papaya strain of Papaya ringspot virus (PRSV-P) in French Polynesia and the Cook Islands

The papaya strain of Papaya ringspot virus (PRSV-P), the cause of papaya ringspot disease, was confirmed in French Polynesia and the Cook Islands by double antibody sandwich enzyme linked immunosorbent assay (DAS-ELISA). In French Polynesia, the virus has probably been on the islands of Tahiti and Moorea for several years, but appears not to have spread to eight other islands. In contrast, PRSV-P has only recently appeared in the Cook Islands and is now the subject of an eradication campaign.

Sperm production rates in Bos indicus strain bulls

Materials and Methods. Testes were collected a t castration or a t slaughter from purebred Brahman (B); Brahman cross (BX - half and three quarter); Sahiwal cross (SX – three quarter and seven eighths); and purebred and three quarter Santa Gertrudis (SG) bulls of known ages between 19 and 27 months and drawn from herds in northern coastal Queensland. 13th Biennial Conference. August 1980, Perth Western Australia.

Antibody response against endogenous stages of an attenuated strain of Eimeria tenella

The application of attenuated vaccines for the prevention of chicken coccidiosis has increased exponentially in recent years. In Eimeria infections, protective immunity is thought to rely on a strong cell mediated response with antibodies supposedly playing a minor role. However, under certain conditions antibodies seem to be significant in protection. Furthermore, antibodies could be useful for monitoring natural exposure of flocks to Eimeria spp. and for monitoring the infectivity of live vaccines. Our objective was to investigate the chicken antibody response to the different parasite lifecycle stages following infection with an attenuated strain of Eimeria tenella. Western blotting analysis of parasite antigens prepared from the lining of caeca infected with the attenuated strain of E. tenella revealed two dominant antigens of 32 and 34 kDa, apparently associated with trophozoites and merozoites that were present at high concentrations between 84 and 132 h post-infection. When cryosections of caeca infected with E. tenella were probed with IgY purified from immune birds the most intense reaction was observed with the asexual stages. Western blotting analysis of proteins of purified sporozoites and third generation merozoites and absorption of stage-specific antibodies from sera suggested that a large proportion of antigens is shared by the two stages. The time-courses of the antibody response to sporozoite and merozoite antigens were similar but varied depending on the inoculation regime and the degree of oocyst recirculation.

Fungal colonization of sago starch in Papua New Guinea

Sago starch is an important source of dietary carbohydrates in lowland Papua New Guinea. Over the past 30 years there have been sporadic reports of severe illness following consumption of sago starch. A common assumption is that fungal metabolites might be associated with the illness, leading to the need for a more thorough investigation of the mycoflora of sago starch. Sago starch was collected from areas of high sago consumption in Papua New Guinea for fungal analysis (69 samples). Storage methods and duration were recorded at the time of collection and pH on arrival at the laboratory. Yeasts were isolated from all samples except two, ranging from 1.2 × 103 to 8.3 × 107 cfu/g. Moulds were isolated from 65 of the 69 samples, ranging from 1.0 × 102 to 3.0 × 106 cfu/g. Of 44 samples tested for ergosterol content, 42 samples showed the presence of fungal biomass. Statistical analyses indicated that sago starch stored for greater than five weeks yielded significantly higher ergosterol content and higher numbers of moulds than sago stored for less than five weeks. The method of storage was also shown to influence mould numbers with storage in natural woven fibre containers returning significantly greater numbers than present in other storage methods tested. Potentially mycotoxigenic genera of moulds including Aspergillus and Penicillium were commonly isolated from sago starch, and as such storage factors that influence the growth of these and other filamentous fungi might contribute to the safety of traditional sago starch in PNG.

Global trade in ornamental fish from an Australian perspective: The case for revised import risk analysis and management strategies

Over 1 billion ornamental fish comprising more than 4000 freshwater and 1400 marine species are traded internationally each year, with 8-10 million imported into Australia alone. Compared to other commodities, the pathogens and disease translocation risks associated with this pattern of trade have been poorly documented. The aim of this study was to conduct an appraisal of the effectiveness of risk analysis and quarantine controls as they are applied according to the Sanitary and Phytosanitary (SPS) agreement in Australia. Ornamental fish originate from about 100 countries and hazards are mostly unknown; since 2000 there have been 16-fold fewer scientific publications on ornamental fish disease compared to farmed fish disease, and 470 fewer compared to disease in terrestrial species (cattle). The import quarantine policies of a range of countries were reviewed and classified as stringent or non-stringent based on the levels of pre-border and border controls. Australia has a stringent policy which includes pre-border health certification and a mandatory quarantine period at border of 1-3 weeks in registered quarantine premises supervised by government quarantine staff. Despite these measures there have been many disease incursions as well as establishment of significant exotic viral, bacterial, fungal, protozoal and metazoan pathogens from ornamental fish in farmed native Australian fish and free-living introduced species. Recent examples include Megalocytivirus and Aeromonas salmonicida atypical strain. In 2006, there were 22 species of alien ornamental fish with established breeding populations in waterways in Australia and freshwater plants and molluscs have also been introduced, proving a direct transmission pathway for establishment of pathogens in native fish species. Australia's stringent quarantine policies for imported ornamental fish are based on import risk analysis under the SPS agreement but have not provided an acceptable level of protection (ALOP) consistent with government objectives to prevent introduction of pests and diseases, promote development of future aquaculture industries or maintain biodiversity. It is concluded that the risk analysis process described by the Office International des Epizooties under the SPS agreement cannot be used in a meaningful way for current patterns of ornamental fish trade. Transboundary disease incursions will continue and exotic pathogens will become established in new regions as a result of the ornamental fish trade, and this will be an international phenomenon. Ornamental fish represent a special case in live animal trade where OIE guidelines for risk analysis need to be revised. Alternatively, for countries such as Australia with implied very high ALOP, the number of species traded and the number of sources permitted need to be dramatically reduced to facilitate hazard identification, risk assessment and import quarantine controls. Lead papers of the eleventh symposium of the International Society for Veterinary Epidemiology and Economics (ISVEE), Cairns, Australia

First fungal pathogen to be utilized for weed biocontrol in Fiji and Papua New Guinea

Biological control of weeds has been carried out in Fiji since 1911, when the seed-fly Ophiomyia lantanae was introduced in an attempt to control Lantana camara. In 1988, the thrips Liothrips mikaniae was introduced from Trinidad into the Solomon Islands in an attempt to undertake biocontrol of Mikania micrantha (mikania) in the Pacific. A small colony of the thrips was subsequently taken from the Solomon Islands to the Kerevat Lowlands Agricultural Experimental Station in New Britain, Papua New Guinea (PNG). Now two decades later and for the first time, a pathogenic rust fungus has been imported for use against mikania, one of Fiji’s and the Pacific’s worst invasive weeds.

Forest health guide: symptoms of insect and fungal damage on trees

The Forest health guide: symptoms of insect and fungal damage on trees is intended to help forestry and quarantine staff undertake tree health assessments, in both forest and urban environments. The guide is designed to be used as a quick reference to common symptoms of damage, not as an identification guide to particular insect pests and pathogens.

Fungal Biopesticide for cattle tick and buffalo fly control

Cattle ticks and buffalo flies impose significant economic burdens on the Northern Australian cattle and dairy industries. With the increased temperatures expected under climate change the range of parasites such as these is likely to extend. Current control options for these ectoparasites are limited by problems associated with chemical resistance and residues. Fungal biopesticides offer a sustainable and promising alternative method of control. Laboratory and animal studies have established the potential for the fungus Metarhizium in tick control and provided data that suggests a secondary effect of buffalo fly control is possible. Small field trials are required to obtain a proof of concept for the control of ticks and buffalo flies on animals.

Feasiblity Study into fungal biocontrol of small hive beetle

Investigation of potential for fungal control of small hive beetles.

Verticillium dahliae (defoliating strain) - cotton, vegetables

DAFF scholarship to train in the recognition and identification of defoliating strains of Verticillium dahliae in cotton and vegetable crops.

Comparison of bioassay responses to the potential fungal biopesticide Metarhizium anisopliae in Rhipicephalus(Boophilus) microplus and Lucilia cuprina.

Quantal response bioassays were conducted with cattle ticks and sheep blowflies with three different isolates of Metarhizium anisopliae and different methods of inoculation. Ticks were either topically dosed with 2 mu l or immersed in the conidial preparations. Blowflies were either topically dosed with 2 mu l of the conidial preparation or fed on conidia mixed with sugar. Probit analyses were carried out on the mortality data to compare the virulence of these isolates to ticks and blowflies and look for indications of different virulence mechanisms employed by M. anisopliae isolates when invading these hosts. One isolate (ARIM16) showed high virulence to both hosts killing 95% of ticks after 2 days and 88 (+/- 2)% of blowflies after 4 days. Strikingly different mortality patterns indicated that virulence is dependent on different mechanisms in ticks and blowflies. The pattern of mortality seen with ticks suggested that the number of conidia adhering per unit area of the cuticle was more important for rapid tick death than the total number of conidia contacting the entire tick surface. Blowflies fed conidia mixed with food died rapidly after an initial lag phase regardless of dose.

Bacterial and fungal community composition over time in chicken litter with high or low moisture content

1. Changes in bacterial and fungal communities in chicken litter with high and low moisture content over a five week period during a single chicken grow out cycle in a poultry shed in subtropical Australia were investigated to study the association between specific microbes and odour production. 2. Microbial biomass, as indicated by DNA yields, was higher and community composition was more dynamic over time in moist compared with dry chicken litter. 3. Bacillus, Atopostipes and Aspergillus species increased in relative abundance in moist chicken litter samples over time reflecting the relatively high fitness and hence activity of these specific bacteria and this specific fungus in this environment.