140 research outputs found
Internal parasites and association with diarrhoea in sheep at an abattoir in Western Australia
Diarrhoea (scouring) is an important issue for the sheep meat industry. Scouring is a major risk factor for fleece soiling and consequential carcase contamination with microbes that cause meat spoilage and potential dangers for humans (2). There is little information on the causes of scouring in sheep at slaughter. Strongyle worm infections are commonly implicated in scouring and reduced production, yet there is no published data quantifying strongyle infections in scouring and normal sheep at abattoirs. In addition, Giardia and Cryptosporidium have been associated with scouring in ruminants, but little is known about the prevalence, genotypes present or the effect on production in sheep populations. This study carried out at an abattoir in Western Australia (WA), aimed to investigate the extent of strongyle, Giardia and Cryptosporidium infections and any association with scouring in sheep
Molecular and morphological characterization of Echinococcus granulosus of human and animal origin in Iran
Iran is an important endemic focus of cystic hydatid disease (CHD) where several species of intermediate host are commonly infected with Echinococcus granulosus. Isolates of E. granulosus were collected from humans and other animals from different geographical areas of Iran and characterized using both DNA (PCR-RFLP of ITS1) and morphological criteria (metacestode rostellar hook dimensions). The sheep and camel strains/genotypes were shown to occur in Iran. The sheep strain was shown to be the most common genotype of E. granulosus affecting sheep, cattle, goats and occasionally camels. The majority of camels were infected with the camel genotype as were 3 of 33 human cases. This is the first time that cases of CHD in humans have been identified in an area where a transmission cycle for the camel genotype exists. In addition, the camel genotype was found to cause infection in both sheep and cattle. Results also demonstrated that both sheep and camel strains can be readily differentiated on the basis of hook morphology alone
Molecular identification of naturally acquired strongylid infections in lambs - An investigation into how lamb age influences diagnostic sensitivity
Faecal samples (n= 1155) were collected from n= 111 (Farm A) and n= 124 (Farm B) 2-6 week old female lambs on two farms in southern Western Australia across five sampling occasions (spanning 8 months). Genomic DNA was extracted directly from faecal samples and screened by PCR for ITS-2 nuclear ribosomal DNA to detect patent strongylid infections, specifically Teladorsagia circumcincta, Trichostrongylus spp., Haemonchus contortus, Oesophagostomum spp. and Chabertia ovina. The minimum amount of extracted genomic DNA necessary for successful PCR amplification was 2.0-5.0. pg.During the five sampling occasions for the two farms, the sensitivities for WEC and PCR identification of strongylid infections varied, with levels of agreement between the two sets of diagnostic results ranging from 85 to 100%. Strongylid species prevalences were high (90.3-97.3%), with T. circumcincta and Trichostrongylus spp. the most prevalent species and together they were the most common mixed strongylid infection; H. contortus was not identified in either flock. T. circumcincta was the only species associated with an increased risk of non-pelleted faeces on Farm B, where T. circumcincta-positive lambs were 2.3 and 2.6 times more likely to have non-pelleted faeces than negative lambs at the second and final samplings, respectively. The highest strongylid prevalence, mixed strongylid prevalence and mean number of strongylid species detected per lamb coincided with the highest average flock faecal worm egg counts (WECs) on both farms. There was a positive correlation between the number of strongyle species detected per lamb and both WEC and adjusted WEC (P<0.01; r 2 0.026-0.591).These results indicate that strongylid eggs were likely to be the main source of strongylid DNA in the faecal DNA extracts. Despite the progress made by the molecular approach utilised in this study, it is incapable of distinguishing between patent and non-patent sources of strongylid DNA. However there is potential for further investigation into the development of a similar molecular procedure which could be used for early larvae detection on pastures
Detection and phylogenetic characterisation of novel Anaplasma and Ehrlichia species in Amblyomma triguttatum subsp. from four allopatric populations in Australia
Anaplasma and Ehrlichia spp. are tick-borne pathogens that can cause severe disease in domestic animals, and several species are responsible for emerging zoonoses in the northern hemisphere. Until recently, the only members of these genera reported in Australia (A. marginale, A. centrale, and A. platys) were introduced from other continents, through the importation of domestic animals and their associated ticks. However, unique Anaplasma and Ehrlichia 16S rRNA gene sequences were recently detected for the first time in native Australian ticks, particularly in Amblyomma triguttatum subsp. ticks from southwest Western Australia (WA). We used molecular techniques to survey Am. triguttatum subsp. ticks from four allopatric populations in southern and western Australia for Anaplasma and Ehrlichia species, and described here the phylogeny of these novel organisms. An A. bovis variant (genotype Y11) was detected in ticks from two study sites; Yanchep National Park (12/280, 4.3%) and Barrow Island (1/69, 1.4%). Phylogenetic analysis of 16S rRNA and groEL gene sequences concluded that A. bovis genotype Y11 is a unique genetic variant, distinct from other A. bovis isolates worldwide. Additionally, a novel Ehrlichia species was detected in Am. triguttatum subsp. from three of the four study sites; Yanchep National Park (18/280, 6.4%), Bungendore Park (8/46, 17.4%), and Innes National Park (9/214, 4.2%), but not from Barrow Island. Phylogenetic analysis of 16S, groEL, gltA, and map1 gene sequences revealed that this Ehrlichia sp. is most closely related to, but clearly distinct from, E. ruminantium and Ehrlichia sp. Panola Mountain. We propose to designate this new species '. Candidatus Ehrlichia occidentalis'. Anaplasma bovis genotype Y11 and 'Candidatus E. occidentalis' are the first Anaplasma and Ehrlichia species to be recorded in native Australian ticks
Recent insights into the tick microbiome gained through next-generation sequencing
The tick microbiome comprises communities of microorganisms, including viruses, bacteria and eukaryotes, and is being elucidated through modern molecular techniques. The advent of next-generation sequencing (NGS) technologies has enabled the genes and genomes within these microbial communities to be explored in a rapid and cost-effective manner. The advantages of using NGS to investigate microbiomes surpass the traditional non-molecular methods that are limited in their sensitivity, and conventional molecular approaches that are limited in their scalability. In recent years the number of studies using NGS to investigate the microbial diversity and composition of ticks has expanded. Here, we provide a review of NGS strategies for tick microbiome studies and discuss the recent findings from tick NGS investigations, including the bacterial diversity and composition, influential factors, and implications of the tick microbiome
A survey of ticks (Acari: Ixodidae) of companion animals in Australia
Background: Ticks are among the most important vectors of pathogens affecting companion animals, and also cause health problems such as tick paralysis, anaemia, dermatitis, and secondary infections. Twenty ixodid species have previously been recorded on dogs, cats, and horses in Australia, including Rhipicephalus sanguineus, Ixodes holocyclus and Haemaphysalis longicornis, which transmit tick-borne diseases. A survey of hard ticks (Acari: Ixodidae) was conducted during 2012-2015 to investigate tick species that infest dogs, cats, and horses in Australia. Methods: Individual tick specimens were collected from dogs, cats and horses across Australia and sample collection locations were mapped using QGIS software. Ticks were morphologically examined to determine species, instar and sex. The companion animal owners responded to questionnaires and data collected were summarised with SPSS software. Results: A total of 4765 individual ticks were identified in this study from 7/8 states and territories in Australia. Overall, 220 larvae, 805 nymphs, 1404 males, and 2336 females of 11 tick species were identified from 837 companion animal hosts. One novel host record was obtained during this study for Ixodes myrmecobii, which was found on Felis catus (domestic cat) in the town of Esperance, Western Australia. The most common tick species identified included R. sanguineus on dogs (73 %), I. holocyclus on cats (81 %) and H. longicornis on horses (60 %). Conclusions: This study is the first of its kind to be conducted in Australia and our results contribute to the understanding of the species and distribution of ticks that parasitise dogs, cats, and horses in Australia. Records of R. sanguineus outside of the recorded distribution range emphasise the need for a systematic study of the habitat range of this species. Several incomplete descriptions of ixodid species encountered in this study hindered morphological identification
Identification of novel trypanosome genotypes in native Australian marsupials
In the present study, the occurrence and molecular phylogeny of trypanosome parasites were studied in both wild and captive marsupials from Western Australia and Queensland. Blood samples were screened by PCR at the 18S rDNA locus, and the glycosomal glyceraldehyde phosphate dehydrogenase gene. Overall, 5.3% of the blood samples were positive at the 18S rDNA locus. All positives belonged to wild-captured Western Australian individuals, where trypanosome-specific DNA was detected in 9.8% of the screened samples from wild marsupials, in common brushtail possums, and woylies. The detection rate of trypanosome DNA in these two host species was 12.5% and 20%, respectively. Phylogenetic analyses based on two loci, indicated that the possum-derived trypanosome isolates were genetically distinct, and most closely related to the Australian marsupial trypanosomes H25 from a kangaroo, and BRA2 from a bush rat. This is the first study to genetically characterise trypanosome isolates from possums. The analysis of the woylie-derived isolates demonstrated that this marsupial host can harbour multiple genotypes within the same geographical location and furthermore multiple genotypes within the same host, indicative of mixed infections. All the woylie-derived genotypes grouped with trypanosomes found in Australian marsupials, suggesting that they are more likely to belong to an endemic or Australasian trypanosome species. This is the first study to genetically characterise trypanosome isolates from possums (Trichosurus vulpecula). Although the clinical significance of these infections is currently unknown, the identification of these novel sequences may support future investigations on transmission, threats to endangered wildlife, and evolutionary history of the genus Trypanosoma
Illuminating the bacterial microbiome of Australian ticks with 16S and Rickettsia-specific next-generation sequencing
Next-generation sequencing (NGS) studies show that mosquito and tick microbiomes influence the transmission of pathogens, opening new avenues for vector-borne pathogen control. Recent microbiological studies of Australian ticks highlight fundamental knowledge gaps of tick-borne agents. This investigation explored the composition, diversity and prevalence of bacteria in Australian ticks (n = 655) from companion animals (dogs, cats and horses). Bacterial 16S NGS was used to identify most bacterial taxa and a Rickettsia-specific NGS assay was developed to identify Rickettsia species that were indistinguishable at the V1-2 regions of 16S. Sanger sequencing of near full-length 16S was used to confirm whether species detected by 16S NGS were novel. The haemotropic bacterial pathogens Anaplasma platys, Bartonella clarridgeiae, “Candidatus Mycoplasma haematoparvum” and Coxiella burnetii were identified in Rhipicephalus sanguineus (s.l.) from Queensland (QLD), Western Australia, the Northern Territory (NT), and South Australia, Ixodes holocyclus from QLD, Rh. sanguineus (s.l.) from the NT, and I. holocyclus from QLD, respectively. Analysis of the control data showed that cross-talk compromises the detection of rare species as filtering thresholds for less abundant sequences had to be applied to mitigate false positives. A comparison of the taxonomic assignments made with 16S sequence databases revealed inconsistencies. The Rickettsia-specific citrate synthase gene NGS assay enabled the identification of Rickettsia co-infections with potentially novel species and genotypes most similar (97.9–99.1%) to Rickettsia raoultii and Rickettsia gravesii. “Candidatus Rickettsia jingxinensis” was identified for the first time in Australia. Phylogenetic analysis of near full-length 16S sequences confirmed a novel Coxiellaceae genus and species, two novel Francisella species, and two novel Francisella genotypes. Cross-talk raises concerns for the MiSeq platform as a diagnostic tool for clinical samples. This study provides recommendations for adjustments to Illuminaʼs 16S metagenomic sequencing protocol that help track and reduce cross-talk from cross-contamination during library preparation. The inconsistencies in taxonomic assignment emphasise the need for curated and quality-checked sequence databases
Evaluation of 16S next-generation sequencing of hypervariable region 4 in wastewater samples: An unsuitable approach for bacterial enteric pathogen identification
Recycled wastewater can carry human-infectious microbial pathogens and therefore wastewater treatment strategies must effectively eliminate pathogens before recycled wastewater is used to supplement drinking and agricultural water supplies. This study characterised the bacterial composition of four wastewater treatment plants (WWTPs) (three waste stabilisation ponds and one oxidation ditch WWTP using activated sludge treatment) in Western Australia. The hypervariable region 4 (V4) of the bacterial 16S rRNA (16S) gene was sequenced using next-generation sequencing (NGS) on the Illumina MiSeq platform. Sequences were pre-processed in USEARCH v10.0 and denoised into zero-radius taxonomic units (ZOTUs) with UNOISE3. Taxonomy was assigned to the ZOTUs using QIIME 2 and the Greengenes database and cross-checked with the NCBI nr/nt database. Bacterial composition of all WWTPs and treatment stages (influent, intermediate and effluent) were dominated by Proteobacteria (29.0-87.4%), particularly Betaproteobacteria (9.0-53.5%) and Gammaproteobacteria (8.6-34.6%). Nitrifying bacteria (Nitrospira spp.) were found only in the intermediate and effluent of the oxidation ditch WWTP, and denitrifying and floc-forming bacteria were detected in all WWTPs, particularly from the families Comamonadaceae and Rhodocyclales. Twelve pathogens were assigned taxonomy by the Greengenes database, but comparison of sequences from genera and families known to contain pathogens to the NCBI nr/nt database showed that only three pathogens (Arcobacter venerupis, Laribacter hongkongensis and Neisseria canis) could be identified in the dataset at the V4 region. Importantly, Enterobacteriaceae genera could not be differentiated. Family level taxa assigned by Greengenes database agreed with NCBI nr/nt in most cases, however, BLAST analyses revealed erroneous taxa in Greengenes database. This study highlights the importance of validating taxonomy of NGS sequences with databases such as NCBI nr/nt, and recommends including the V3 region of 16S in future short amplicon NGS studies that aim to identify bacterial enteric pathogens, as this will improve taxonomic resolution of most, but not all, Enterobacteriaceae species
Molecular investigation into the presence of a Coxiella sp. in Rhipicephalus sanguineus ticks in Australia
Q fever is an infectious disease with a global distribution caused by the intracellular bacterium, Coxiella burnetii, which has been detected in a large number of tick species worldwide, including the brown dog tick, Rhipicephalus sanguineus. Recent reports of a high seroprevalance of C. burnetii in Australian dogs, along with the identification of additional Coxiella species within R. sanguineus ticks, has prompted an investigation into the presence and identification of Coxiella species in R. sanguineus ticks in Australia. Using a combination of C. burnetii species-specific IS1111a transposase gene and Coxiella genus-specific 16S rRNA PCR assays, a Coxiella sp. was identified in 100% (n = 199) of R. sanguineus ticks analysed, and C. burnetii was not detected in any R. sanguineus ticks studied. Phylogenetic analysis of the 16S rRNA gene revealed the Coxiella sequences were closely related to Coxiella sp. identified previously in R. sanguineus and R. turanicus ticks overseas. This study illustrates the value of using genus specific PCR assays to detect previously unreported bacterial species. Furthermore, the presence of an additional Coxiella sp. in Australia requires further investigation into its potential for contributing to serological cross-reactions during Q fever testing
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