Search

In Western Australia a number of indigenous Trypanosoma spp. infect susceptible native marsupials, such as the woylie ( Bettongia penicillata ), brushtail possum ( Trichosurus vulpecula ), and chuditch (Dasyurus geoffroii ). Two genotypes of Trypanosoma copemani (identified as G1 and G2) have been found in the woylie, and G2 has been implicated in the decline of this host species, making its presence of particular interest. Here we used targeted amplicon next generation sequencing (NGS) of the Trypanosoma 18S rDNA loci on 70 Trypanosoma -positive marsupial blood samples, to identify T. copemani genotypes and multiple Trypanosoma infections (polyparasitism) in woylies and cohabiting species in Western Australia. Polyparasitism with Trypanosoma spp. was found in 50% of the wildlife sampled, and within species diversity was high, with 85 zero-radius operational taxonomic units (ZOTUs) identified in nine putative parasite species. Trypanosoma copemani was assigned 17 ZOTUs and was identified in 80% of samples. The most abundant ZOTU isolated (63%) differed slightly from the published genotype of G1, and G2 was the second most abundant ZOTU (14%). Trypanosome diversity was significantly greater in woylies than in brushtail possums, and parasite community composition also differed significantly between these host species. One novel Trypanosoma spp. genotype ( Trypanosoma sp. ANU2) was found in 20% of samples. A species of Crithidia was detected in a woylie, and two avian trypanosomes ( Trypanosoma avium and Trypanosoma sp. AAT) were identified in woylies for the first time.

Parasites are the most abundant form of life on earth and are vital components of ecosystem health. Yet, it is only relatively recently that attention has been given to the risks of extinction that parasites face when their hosts, particularly wildlife, are endangered. In such circumstances, parasites that are host-specific with complicated life cycles are most at risk. Such extinction/coextinction events have been poorly documented, principally because of the difficulties of following such extinction processes in nature. Fortunately, we were presented with the rare opportunity to catalogue an endangered Australian marsupial's parasites; we present our near-complete catalogue here. We incorporate this catalogue into a predictive framework to understand which parasites might be most vulnerable to coextinction, which we hope will serve as a model for endangered hosts and their parasites elsewhere., (Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.)

Taenia solium taeniasis-cysticercosis and soil-transmitted helminths (STHs) are parasitic Neglected Tropical Diseases endemic throughout Southeast Asia. Within Lao PDR, a remote northern hill tribe village had previously been identified as a hyper endemic focus for T. solium. To reduce this observed prevalence, a One Health intervention covering both pigs and humans was implemented, which included two Mass drug administrations (MDA1 and MDA2) for village residents using a triple dose albendazole 400mg treatment regime. In addition to the effect on T. solium levels, the dual impact of this anthelmintic regime on STHs within the community was also monitored. Faecal samples were collected pre and post MDA1 and MDA2 and analysed for the presence of Taenia species and the STHs Ascaris lumbricoides, Trichuris trichiura and hookworm species. The McMaster technique was used to measure the changes in both prevalence and intensity of infection. Molecular characterisation of Taenia and hookworm species was conducted to detect zoonotic species. The level of taeniasis within the sampled population decreased by 79.4% after MDA1, remained steady during the five month inter-treatment interval and decreased again by 100% after MDA2. The prevalence of STHs decreased by 65.5% and 62.8% after MDA1 and MDA2 respectively; however an increase to 62.1% of pre MDA1 levels was detected during the inter-treatment interval. Individually, hookworm prevalence decreased by 83.4% (MDA1) and 84.5% (MDA2), A. lumbricoides by 95.6% and 93.5% and T. trichiura by 69.2% and 61%. The intensity of infection within the sampled population also decreased, with egg reduction rates of 94.4% and 97.8% for hookworm, 99.4% and 99.3% for A. lumbricoides and 77.2% and 88.5% for T. trichiura. Molecular characterisation identified a T. solium tapeworm carrier from 21.6% (13/60) of households in the village. T. saginata was identified in 5% (3/60) of households. The zoonotic hookworm A. ceylanicum was detected in the resident dog population. These results suggest that the triple dose albendazole 400mg treatment regime achieved a significant reduction in the level of taeniasis whilst simultaneously reducing the STH burden within the village. The increased STH prevalence detected between MDAs reflects the need for behavioural changes and a sustained chemotherapy programme, which may also need to include the resident dog population., (Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Molecular and structural information on avian Trypanosoma spp. throughout Australia is limited despite their intrinsic value in understanding trypanosomatid evolution, diversity, and structural biology. In Western Australia tissue samples (n = 429) extracted from 93 birds in 25 bird species were screened using generic PCR primers to investigate the diversity of Trypanosoma spp. To investigate avian trypanosome structural biology the first 3-dimensional ultrastructural models of a Trypanosoma spp. (Trypanosoma sp. AAT) isolated from a bird (currawong, Strepera spp.) were generated using focussed ion beam milling combined with scanning electron microscopy (FIB-SEM)., Results: Here, we confirm four intercontinental species of avian trypanosomes in native Australian birds, and identify a new avian Trypanosoma. Trypanosome infection was identified in 18 birds from 13 different bird species (19%). A single new genotype was isolated and found to be closely related to T. culicavium (Trypanosoma sp. CC2016 B002). Other Trypanosoma spp. identified include T. avium, T. culicavium, T. thomasbancrofti, Trypanosoma sp. TL.AQ.22, Trypanosoma sp. AAT, and an uncharacterised Trypanosoma sp. (group C-III sensu Zidková et al. (Infect Genet Evol 12:102-112, 2012)), all previously identified in Australia or other continents. Serially-sectioning Trypanosoma sp. AAT epimastigotes using FIB-SEM revealed the disc-shaped kinetoplast pocket attached perpendicular to the branching mitochondrion. Additionally, the universal minicircle sequence within the kinetoplast DNA and the associated binding protein were determined in Trypanosoma sp. AAT., Conclusions: These results indicate that bird trypanosomes are relatively conserved across continents, while being locally diverse, which supports the hypothesis that bird trypanosomes exist as fewer species than described in the literature. Evidence exists that avian Trypanosoma spp. are infecting mammals and could be transmitted by haemadipsid leeches. Trypanosoma sp. AAT is most likely a separate species currently found only in Australia and the first 3-dimentional ultrastructural analysis of an avian trypanosome provides interesting information on their morphology and organelle arrangement.

Ancylostoma ceylanicum is the common hookworm of domestic dogs and cats throughout Asia, and is an emerging but little understood public health risk in tropical northern Australia. We investigated the prevalence of A. ceylanicum in soil and free-ranging domestic dogs at six rainforest locations in Far North Queensland that are Indigenous Australian communities and popular tourist attractions within the Wet Tropics World Heritage Area. By combining PCR-based techniques with traditional methods of hookworm species identification, we found the prevalence of hookworm in Indigenous community dogs was high (96.3% and 91.9% from necropsy and faecal samples, respectively). The majority of these infections were A. caninum. We also observed, for the first time, the presence of A. ceylanicum infection in domestic dogs (21.7%) and soil (55.6%) in an Indigenous community. A. ceylanicum was present in soil samples from two out of the three popular tourist locations sampled. Our results contribute to the understanding of dogs as a public health risk to Indigenous communities and tourists in the Wet Tropics. Dog health needs to be more fully addressed as part of the Australian Government's commitments to "closing the gap" in chronic disease between Indigenous and other Australians, and encouraging tourism in similar locations.

Parasites of wildlife inhabiting urbanised and peri-urban environments are of interest regarding wildlife population health, and also veterinary public health in the case of parasites that can also infect humans and domestic animals. This study aimed to: identify, and estimate the prevalence of, species of Eimeria parasitic in quenda (Isoodon obesulus) in the greater Perth region, Western Australia; 2) morphologically describe and genetically characterise a novel observed species of Eimeria as E. angustus; and 3) genetically characterise E. kanyana. Eimeria spp. prevalence was 76.1% (95% CI 64.9-84.5%), and four putative species of Eimeria were identified. Eimeria kanyana was identified infecting quenda for the first time, with a prevalence of 54.9% (43.4-66.0%). Eimeria quenda was less prevalent, at 7.0% (3.1-15.5%). The novel species E. angustus was present in 45.1% of sampled quenda (34.0-56.6%). A second novel morphotype of Eimeria was present in 2.8% of sampled quenda (0.9-9.7%). Mixed Eimeria spp. infections were present in 21/71 quenda (29.6%, 95% CI 20.2-41.1%). Molecular phylogenetic analyses of E. kanyana and E. angustus were conducted at the 18S rRNA and mitochondrial cytochrome oxidase loci. At both loci, two isolates identified as E. kanyana grouped in a phylogenetic clade with E. trichosuri. Five isolates identified as the novel E. angustus were most closely related to E. tropidura at the 18S locus. At the COI locus, no sequence data were available for E. tropidura; isolates of E. angustus grouped with E. sciurorum., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Giardia and Cryptosporidium are ubiquitous enteric protozoan pathogens of vertebrates. Although recognised as the aetiological agents of disease in humans and domestic animals for many years, fundamental questions concerning their ecology have been unresolved. Molecular tools have helped to better understand their genetic diversity and in so doing have helped to resolve questions about their transmission patterns and associated impacts on public health. However, the value of molecular tools is often complicated by questions concerning their applications, interpretation of results and terminology. Taxonomic issues have, until recently, made it difficult to determine the epidemiology of infections with both Giardia and Cryptosporidium. Similarly, improved understanding of their respective phylogenetic relationships has helped to resolve questions about zoonotic potential and distribution in wildlife. In the case of Cryptosporidium, imaging technologies have complemented phylogenetic studies in demonstrating the parasite's affinities with gregarine protozoa and have further supported its extracellular developmental capability and potential role as an environmental pathogen., (Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.)

The 'quenda genotype' of Giardia was first identified in quenda (syn. southern brown bandicoots, Isoodon obesulus ) in Western Australia in 2004. We aimed to formally describe this genotype as a species of Giardia , Giardia peramelis . Seventy five faecal samples positive for G . peramelis were obtained from quenda within the Statistical Division of Perth, Western Australia. These samples were used in morphological and molecular characterisation of G . peramelis . PCR amplification and sequencing was most successful at the 18S rRNA and ITS1-5.8s-ITS2 loci. Phylogenetic analyses placed G . peramelis external to the ' Giardia duodenalis species complex' and Giardia microti . This confirmed the uniqueness of G . peramelis , warranting classification as a separate species of Giardia . Study findings suggest quenda are a natural host for G . peramelis .

Cryptosporidium is a parasite responsible for widespread disease in livestock and humans. Recent phylogenetic reclassification of Cryptosporidium from a coccidian to a gregarine dictates an urgent need to reconsider the biology and behavior of this parasite. Overwhelming data now confirm that, like its close relatives, Cryptosporidium is a facultatively epicellular apicomplexan that is able to multiply in a host cell-free environment. We complement the latest phylogenetic and taxonomic proposals with advances in our understanding of Cryptosporidium's biology, with particular focus on in vitro studies that have characterized the development of Cryptosporidium stages in the absence of host cells. Opportunities to revisit in vivo infections are discussed and questions about the Cryptosporidium host cell-free life cycle that remain unanswered highlighted., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

This report describes the detection and molecular characterisation of Neospora/Hammondia-like oocysts from naturally infected dogs. Single faecal samples were collected from 160 individual greyhounds and multiple faecal samples were collected from 5 Labrador litters within a breeding kennel. Microscopy analysis detected Neospora/Hammondia like oocysts in 2 greyhounds and one litter of Labrador puppies. PCR protocols targeting the internal transcribed spacer region (ITS-1) and the large subunit (LSU) rDNA (D2/D3 domains) confirmed the presence of H. heydorni in both greyhounds and N. caninum in the Labrador litter. Dietary information obtained for all positive dogs indicate the source of infection was through regular exposure to a commercially obtained raw meat diet. These results report for the first time a natural infection with H. heydorni in dogs in Australia and also the first co-occurrence of N. caninum and H. heydorni in an Australian urban region., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Trypanosomes infect humans, domestic animals, and wildlife, and are transmitted by haematophagous invertebrate vectors. Eight native trypanosome species have been described from Australian indigenous mammals, along with other unnamed isolates and genotypes. Associated difficulties relating to the confirmation of cyclical and mechanical vector candidates has hindered vector identification in Australia, with no successful experimental transmission documented for any of these native trypanosomes to indigenous mammals. We discuss pending biosecurity issues, with significant importance placed on the close phylogenetic and phenotypic relationship shared between Trypanosoma cruzi and some Australian trypanosomes. With such a dearth of information, we highlight the importance of keeping an open mind, which considers all possibilities during future investigations of vectors and their associated biosecurity issues in Australia., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Reactivation of Chagas Disease (CD) is a global public health issue. Reactivation of disease can affect the management of CD and its clinical outcome, adding pressure to global health systems because it exacerbates symptoms, leading to misdiagnosis and delays in the administration of correct treatments. Concurrent infections complicate the issue of reactivation, because there are various parasites and disease treatment regimens that are able to influence or suppress the immune system of the host, reactivating disease within infected individuals. The effect of delayed symptoms of chronic CD and the potential for disease reactivation are of great importance to nonendemic regions of the world, where knowledge about CD is lacking and the potential for vectorial transmission is not known., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

A total of 1,136 samples from 289 households in four provinces in northern Laos were subjected to Japanese encephalitis virus (JEV) and dengue virus hemagglutination inhibition (DENV HI). Overall, antibodies to JEV were detected by HI in 620 (54.6%) of 1,136 people; of which 217 (19.1%) had HI activity against JEV only. Antibodies to DENV4 were detected by HI in 526 (46.3%) of 1,136 people; of which 124 (10.9%) had HI activity against DENV4 only. Antibodies to DENV1-3 were detected by HI in 296 (26.1%), 274 (24.1%), and 283 (24.9) of 1,136 people, respectively; of which 7, 1, and 0, respectively, had HI activity against DENV1-3 only. JEV was the most prevalent Flavivirus in Oudomxay, Luangprabang, and Huaphan provinces and DENV4 was the most prevalent in Xiengkhouang province. Seroprevalence for JEV increased with increasing age and wealth and was higher in villages where rice was cultivated in paddy fields and highest for people of Lao-Tai ethnicity., (© The American Society of Tropical Medicine and Hygiene.)

Giardia duodenalis assemblage B is potentially a zoonotic parasite. The characterisation and investigation of isolates has been hampered by greater genetic diversity of assemblage B, limiting the application and utility of current genotyping loci. Since whole genome sequencing is the optimal high-throughput method for gene identification, the present study sequenced assemblage B isolate BAH15c1 and compared the sequence to the draft GS references to identify polymorphic genes for potential use in genotyping assays. The majority of the genome sequence was conserved between the two isolates, producing 508 contigs of 10.4 Mb with 4968 genes. Seventy polymorphic genes for potential use in genotyping assays were identified ranging in variation from elongation factor 1 α, which was the most conserved, through to triose phosphate isomerase, which was the most variable., (Copyright © 2015 Elsevier B.V. All rights reserved.)

We conducted a serologic survey of four high-priority pig-associated viral zoonoses, Japanese encephalitis virus (JEV), hepatitis E virus (HEV), Nipah virus (NiV), and swine influenza virus (SIV), in Laos. We collected blood from pigs at slaughter during May 2008-January 2009 in four northern provinces. Japanese encephalitis virus hemagglutination inhibition seroprevalence was 74.7% (95% confidence interval [CI] = 71.5-77.9%), JEV IgM seroprevalence was 2.3% (95% CI = 1.2-3.2%), and HEV seroprevalence was 21.1% (95% CI = 18.1-24.0%). Antibodies to SIV were detected in 1.8% (95% CI = 0.8-2.8%) of pigs by screening enzyme-linked immunosorbent assay, and only subtype H3N2 was detected by hemagglutination inhibition in two animals with an inconclusive enzyme-linked immunosorbent assay result. No NiV antibody-positive pigs were detected. Our evidence indicates that peak JEV and HEV transmission coincides with the start of the monsoonal wet season and poses the greatest risk for human infection.

The application of molecular tools to the characterisation of the aetiological agents of echinococcosis has revealed a series of largely host-adapted species and genotypes that are maintained in distinct cycles of transmission. They can be defined on both genetic and phenotypic characteristics which complement previous observations made by descriptive parasitologists many years ago. A revised taxonomy for species in the genus Echinococcus has been proposed and widely accepted, particularly with respect to forms maintained in transmission cycles involving sheep, horses and cattle. However, molecular epidemiological studies are required in a number of endemic areas in order to determine cycles of transmission responsible for maintaining the parasite. The taxonomic status of forms in cervids, pigs and camels has still to be resolved, and the status and epidemiological significance of newly described species in China requires further research.