Genetic characterization of selected parasites from people with histories of gastrointestinal disorders using a mutation scanning-coupled approach

Associations between canine hookworm infection and dog owners' awareness, perception, and behaviour: A cross-sectional study in Brisbane, Queensland, 2019-2020

Canine hookworms are found globally, and infections have been recorded in domestic dogs visiting dog parks in Queensland, Australia. Some canine hookworms also present a risk of zoonotic transmission to humans. Potential transmission of hookworms can occur in the household and at public places because of lack of owner awareness and poor coverage of canine deworming. Between April 2019 and March 2020, faecal samples from owned dogs were collected from 39 dog parks in metropolitan Brisbane, Queensland, and tested for the presence of hookworm eggs using faecal floatation technique. Dog owners who provided samples were requested to complete a survey on their awareness, perceptions and behaviour regarding the risks and consequences of canine parasitic infection. Associations between dog owner demographics and responses to the survey were measured using Goodman and Kruskal's gamma. Statistical associations between canine hookworm infection in dogs and their owner's responses were quantified using a two-sample Wilcoxon rank-sum test. A total of five canine faecal samples from 175 respondents were found positive for hookworm eggs, corresponding to a sample- and park-level prevalence of 2.86% and 12.82%, respectively. Female dog owners were found to be more aware of the importance of regular deworming of their dogs (|γ| = 0.405). Our results indicate that hookworm infection was associated with a lower awareness of the importance of deworming (p = 0.007), less diligence in administration of deworming (p = 0.004), lower awareness of the risk of acquiring parasites from raw meat (p = 0.010), less likelihood of cooking meat before feeding it to their dogs (p = 0.028), and less likelihood to properly dispose their dog's faeces (p = 0.027). This study not only indicates a need for improving owner education towards the importance of deworming but also a need for changing owner's behaviours to reduce potential environmental contamination with infective hookworms. The latter in particular indicates a broader public health risk of disease transmission in public places due to improper disposal of dog faeces, especially in areas with higher canine hookworm infections.

Genetic diversity and molecular diagnosis of Giardia

Giardia is a genus of flagellated protozoan parasites that infect the small intestine of humans and animals, causing the diarrheal illness known as giardiasis. Giardia exhibits significant genetic diversity among its isolates, which can have important implications for disease transmission and clinical presentation. This diversity is influenced by the coevolution of Giardia with its host, resulting in the development of unique genetic assemblages with distinct phenotypic characteristics. Although panmixia has not been observed, some assemblages appear to have a broader host range and exhibit higher transmission rates. Molecular diagnostic methods enable researchers to examine the genetic diversity of Giardia populations, enhancing our understanding of the genetic diversity, population structure, and transmission patterns of this pathogen and providing insights into clinical presentations of giardiasis.

Advanced approaches for the diagnosis and chemoprevention of canine vector-borne pathogens and parasites-Implications for the Asia-Pacific region and beyond

Vector-borne pathogens (VBPs) of canines are a diverse range of infectious agents, including viruses, bacteria, protozoa and multicellular parasites, that are pernicious and potentially lethal to their hosts. Dogs across the globe are afflicted by canine VBPs, but the range of different ectoparasites and the VBPs that they transmit predominate in tropical regions. Countries within the Asia-Pacific have had limited prior research dedicated to exploring the epidemiology of canine VBPs, whilst the few studies that have been conducted show VBP prevalence to be high, with significant impacts on dog health. Moreover, such impacts are not restricted to dogs, as some canine VBPs are zoonotic. We reviewed the status of canine VBPs in the Asia-Pacific, with particular focus on nations in the tropics, whilst also investigating the history of VBP diagnosis and examining recent progress in the field, including advanced molecular methods, such as next-generation sequencing (NGS). These tools are rapidly changing the way parasites are detected and discovered, demonstrating a sensitivity equal to, or exceeding that of, conventional molecular diagnostics. We also provide a background to the armoury of chemopreventive products available for protecting dogs from VBP. Here, field-based research within high VBP pressure environments has underscored the importance of ectoparasiticide mode of action on their overall efficacy. The future of canine VBP diagnosis and prevention at a global level is also explored, highlighting how evolving portable sequencing technologies may permit diagnosis at point-of-care, whilst further research into chemopreventives will be essential if VBP transmission is to be effectively controlled.

Review of generic screening level assumptions for quantitative microbial risk assessment (QMRA) for estimating public health risks from Australian drinking water sources contaminated with Cryptosporidium by recreational activities

As urban communities continue to grow, demand for recreational access (including swimming) in drinking water sources have increased, yet relatively little is understood about the public health implications this poses for drinking water consumers. Preventative risk-based approaches to catchment management, informed by quantitative microbial risk assessment (QMRA), requires accurate input data to effectively model risks. A sound understanding of the knowledge gaps is also important to comprehend levels of uncertainty and help prioritise research needs. Cryptosporidium is one of the most important causes of waterborne outbreaks of gastroenteritis globally due to its resistance to chlorine. This review was undertaken by Water Research Australia to provide the most up-to-date information on current Cryptosporidium epidemiological data and underlying assumptions for exposure assessment, dose response and risk assessment for generic components of QMRA for Cryptosporidium and highlights priorities for common research. Key interim recommendations and guidelines for numerical values for relatively simple screening level QMRA modelling are provided to help support prospective studies of risks to drinking water consumers from Cryptosporidium due to body-contact recreation in source water. The review does not cover site-specific considerations, such as the levels of activity in the source water, the influence of dilution and inactivation in reservoirs, or water treatment. Although the focus is Australia, the recommendations and numerical values developed in this review, and the highlighted research priorities, are broadly applicable across all drinking source water sources that allow recreational activities.

Neglected tropical diseases in Australia: a narrative review

•Neglected tropical diseases (NTDs) represent a threat to the health, wellbeing and economic prosperity of billions of people worldwide, often causing serious disease or death. •Commonly considered diseases of low and middle-income nations, the presence of NTDs in high income countries such as Australia is often overlooked. •Seven of the 20 recognised NTDs are endemic in Australia: scabies, soil-transmitted helminths and strongyloidiasis, echinococcosis, Buruli ulcer, leprosy, trachoma, and snakebite envenoming. •Dengue, while not currently endemic, poses a risk of establishment in Australia. There are occasional outbreaks of dengue fever, with local transmission, due to introductions in travellers from endemic regions. •Similarly, the risk of introduction of other NTDs from neighbouring countries is a concern. Many NTDs are only seen in Australia in individuals travelling from endemic areas, but they need to be recognised in health settings as the potential consequences of infection can be severe. •In this review, we consider the status of NTDs in Australia, explore the risk of introducing and contracting these infections, and emphasise the negative impact they have on the health of Australians, especially Aboriginal and Torres Strait Islander peoples.

Zoonotic hookworms of dogs and cats - lessons from the past to inform current knowledge and future directions of research

The early-to-mid 1900s was an era that marked the first published reports of clinical cases and experimental human infections that provided valuable evidence to inform our current knowledge on the zoonotic nature of the canid and felid hookworms. To this day, descriptions of the pathognomonic syndromes produced in humans by these early pioneers provide vital information on the putative geographical distribution of these hookworm species, even before their discovery in dogs and cats. Cases of hookworm-related cutaneous larvae migrans and Ancylostoma caninum-induced eosinophilic enteritis continue to be reported in the medical literature, most commonly in recent migrants or returned travellers who have spent time in regions in which these canine and feline hookworms remain highly endemic. Ancylostoma ceylanicum, now recognised as the second most common hookworm infecting humans in the Asia Pacific region, is also being reported in regions of Africa and South America previously assumed free of this parasite. Despite the substantial technological progress made in the field of parasite diagnostics, our knowledge on the epidemiology and population-level morbidity impacts of these zoonotic hookworms in humans has remained relatively stagnant over the last few decades, with 'covert' infections continuing to remain undetected by currently available forms of routine diagnostics. Improved diagnostic tools that enable accurate and rapid species-specific diagnosis of zoonotic hookworm infections in humans are required to provide the necessary evidence to advocate for future investments in One Health-based intervention strategies.

The first molecular identification of benzimidazole resistance in Haemonchus contortus from goats in Thailand

Background and Aim

Haemonchus contortus is one of the major trichostrongyloid nematodes affecting small ruminant production worldwide, especially in tropical and subtropical regions. Adult H. contortus suck the blood from the host abomasum leading to anemia and often death in heavily infected animals. The mainstay of parasitic control is an anthelmintic drug, but long-term drug use may cause drug resistance. The aim of this study was to examine benzimidazole resistance in H. contortus of goats from different regions in Thailand by detecting the frequency of the F200Y polymorphism in the β-tubulin isotype 1 gene.

Materials and Methods

A total of 121 H. contortus adults were obtained from 31 naturally infected out of 37 slaughtered goats from city abattoirs in five regions of Thailand. The frequency of the F200Y polymorphism in the β-tubulin isotype 1 gene was detected following the allele-specific polymerase chain reaction protocol.

Results

The overall genotype frequencies in Thailand were homozygous resistant (RR: 24%), heterozygous (SR: 44.6%), and homozygous susceptible (SS: 31.4%). The allele frequencies were resistant allele (R: 46%) and susceptible allele (S: 54%). The R allele frequency and the RR genotype varied from 30% to 65% and 0% to 43.9%, respectively. The frequency of R alleles was significantly higher in the southern region (0.65) as compared to northern (0.30, p=0.001), western (0.38, p=0.04), and central regions (0.30, p=0.03). The RR genotype was also significantly higher in the southern region (43.9%) versus the northern (0 %, p=0.001), western (11.8%, p=0.012), and central regions (17.4%, p=0.001).

Conclusion

This is the first study of the detection of single-nucleotide polymorphisms in codon 200 of the β-tubulin isotype 1 gene of H. contortus from goats in Thailand. These findings are essential and imply that an integrated approach is needed for issues such as drug treatment, farm management, prevention, and control strategies. This is of interest to farmers, veterinarians, and the department of livestock.

Zoonotic Ancylostomiasis: An Update of a Continually Neglected Zoonosis

Hookworm infections are classified as the most impactful of the human soil-transmitted helminth (STH) infections, causing a disease burden of ∼4 million disability-adjusted life years, with a global prevalence of 406-480 million infections. Until a decade ago, epidemiological surveys largely assumed Necator americanus and Ancylostoma duodenale as the relevant human hookworm species implicated as contributing to iron-deficiency anemia. This assumption was based on the indistinguishable morphology of the Ancylostoma spp. eggs in stool and the absence of awareness of a third zoonotic hookworm species, Ancylostoma ceylanicum. The expanded use of molecular diagnostic assays for differentiating hookworm species infections during STH surveys has now implicated A. ceylanicum, a predominant hookworm of dogs in Asia, as the second most common hookworm species infecting humans in Southeast Asia and the Pacific. Despite this, with the exception of sporadic case reports, there is a paucity of data available on the impact of this emerging zoonosis on human health at a population level. This situation also challenges the current paradigm, necessitating a One Health approach to hookworm control in populations in which this zoonosis is endemic. Here, we have summarized the available research studies and case reports on human A. ceylanicum infections in Southeast Asia and the Pacific after 2013 using a systematic review approach. We summarized eight research articles and five clinical case studies, highlighting the importance of future in-depth investigation of zoonotic A. ceylanicum infections using sensitive and cost-effective diagnostic tools.

Common occurrence of Cryptosporidium hominis in children attending day-care centers in Medellin, Colombia

Cryptosporidium spp. are apicomplexan protozoa associated with chronic diarrhea in AIDS and other immunocompromised patients, and one of the commonest causes of childhood diarrhea and malnutrition, particularly in low-income settings. In Colombia, there are few molecular epidemiological studies on Cryptosporidium spp.; thereby, the transmission dynamics of this parasite in the country is poorly known. This study evaluated the diversity of Cryptosporidium at species, subtype family, and subtype level in children attending various day-care centers in Medellin, Colombia. Two hundred and ninety stool samples from children < 5 years of age were collected from April to November of 2015. All samples were processed by PCR and sequence analysis of the ssu RNA gene and the gp60 gene. An infection rate of 2.4% was observed, with only two Cryptosporidium species identified: C. hominis (6/7) and C. meleagridis (1/7). Cryptosporidium hominis isolates belonged to the subtypes IbA10G2, IaA13R6 and IaA13R7; IIIbA26G1R1 C. meleagridis subtype was also detected. There is a C. hominis predominance in the children evaluated, suggesting an important role of the anthroponotic transmission cycle in the day-care centers analyzed. Further investigation is required to determine infection sources and susceptible hosts in order to define appropriate management of cryptosporidiosis.

Opportunistic Mapping of Strongyloides stercoralis and Hookworm in Dogs in Remote Australian Communities

Both Strongyloides stercoralis and hookworms are common soil-transmitted helminths in remote Australian communities. In addition to infecting humans, S. stercoralis and some species of hookworms infect canids and therefore present both environmental and zoonotic sources of transmission to humans. Currently, there is limited information available on the prevalence of hookworms and S. stercoralis infections in dogs living in communities across the Northern Territory in Australia. In this study, 274 dog faecal samples and 11 faecal samples of unknown origin were collected from the environment and directly from animals across 27 remote communities in Northern and Central Australia. Samples were examined using real-time polymerase chain reaction (PCR) analysis for the presence of S. stercoralis and four hookworm species: Ancylostoma caninum, Ancylostoma ceylanicum, Ancylostoma braziliense and Uncinaria stenocephala. The prevalence of S. stercoralis in dogs was found to be 21.9% (60/274). A. caninum was the only hookworm detected in the dog samples, with a prevalence of 31.4% (86/274). This study provides an insight into the prevalence of S. stercoralis and hookworms in dogs and informs future intervention and prevention strategies aimed at controlling these parasites in both dogs and humans. A "One Health" approach is crucial for the prevention of these diseases in Australia.

Longitudinal analysis of Giardia duodenalis assemblages in animals inhabiting drinking water catchments in New South Wales and Queensland - Australia (2013-2015)

Giardia duodenalis is one of the most common waterborne zoonotic parasites worldwide, and its occurrence in the environment and catchment reservoir water has serious implications for management of drinking water. The aim of the present study was to use molecular tools to identify the Giardia spp. infecting animals inhabiting five drinking water catchments across two states in Australia; New South Wales and Queensland, to better understand the potential health risks they pose. We used quantitative PCR to screen a total of 2174 faecal samples collected from dominant host species in catchment areas for the presence of G. duodenalis. All samples positive for G. duodenalis were further characterized and subtyped at tpi and gdh loci, respectively. The overall prevalence of G. duodenalis was 15.3% (332/2174, 95%CI; 13.8-16.9), and two zoonotic assemblages (assemblages A and B) and one potentially zoonotic assemblage (E) were detected in various host species. Additional subtyping of a subset of samples (n = 76) identified four human infectious sub-assemblages including AI, AII, BII-like and BIV-like, all of which have been previously reported in humans in Australia. The finding of zoonotic assemblages of G. duodenalis in the present study necessitates continued identification of the sources/carriers of human pathogenic strains in drinking water catchment areas for more accurate risk assessment and optimal catchment management.

Cryptosporidium hominis infections in non-human animal species: revisiting the concept of host specificity

Parasites in the genus Cryptosporidium, phylum Apicomplexa, are found worldwide in the intestinal tract of many vertebrate species and in the environment. Driven by sensitive PCR methods, and the availability of abundant sequence data and reference genomes, the taxonomic complexity of the genus has steadily increased; 38 species have been named to date. Due to its public health importance, Cryptosporidium hominis has long attracted the interest of the research community. This species was initially described as infectious to humans only. This perception has persisted in spite of an increasing number of observations of natural and experimental infections of animals with this species. Here we summarize and discuss this literature published since 2000 and conclude that the host range of C. hominis is broader than originally described. The evolving definition of the C. hominis host range raises interesting questions about host specificity and the evolution of Cryptosporidium parasites.

Development of multi-ARMS-qPCR method for detection of hookworms from cats and dogs

Hookworms are blood-sucking nematodes that infect dogs, cats, and humans, causing iron-deficiency anemia, abdominal pain, diarrhea, and skin inflammation. Amplification refractory mutation system (ARMS) is a modified technology based on allele-specific PCR, which is widely used in mutation detection and genotyping. However, no data about ARMS application in hookworm detection. This study aims to establish a multi-ARMS-qPCR method for the detection of three hookworm species from dogs and cats. A universal forward primer and three specific primers (ARMS-Cey, ARMS-Can, and ARMS-Tub) were designed based on the three ITS SNPs (ITS250, ITS78 and ITS153) of Ancylostoma ceylanicum, A. caninum, and A. tubaeforme, respectively. The results showed that the three designed ARMS primers generated specific melting curves for the three hookworms' standard plasmids. The melting temperature (T_m) values were 88.40 °C (A. ceylanicum), 83.15 °C (A. caninum), and 85.65 °C (A. tubaeforme), with good reproducibility of intra- and inter-assay. No amplification was observed with other intestinal parasites. The limit of detection using the established technique was 1, 2, and 104 egg per gram feces (EPG) for A. caninum, A. tubaeforme and A. ceylanicum, respectively. Using multi-ARMS-qPCR assay, 17 out of 50 fecal samples were positive for hookworms, including ten single and seven mixed infections, and single infections were quantified. In conclusion, the used multi-ARMS-qPCR method has the advantages of high efficiency, sensitivity, specificity, and quantitative analysis and can be used for the clinical detection, epidemiological investigation, and zoonotic risk assessment of canine and feline hookworms.

Molecular identification of zoonotic hookworms in dogs from four counties of Kenya

All canine hookworms are known to be zoonotic, causing infections ranging from transient skin irritations to prolonged ‘creeping eruptions’, eosinophilic enteritis and even patent intestinal infections. There is little information on canine hookworm species and their public health significance in sub-Saharan Africa. This study determined the prevalence and species of hookworms in dogs from different climatic zones of Kenya. Dog faecal samples were collected from the environment, and hookworm eggs were isolated by zinc chloride flotation and subjected to DNA extraction. Polymerase chain reaction (PCR) assays targeting the internal transcribed spacer (ITS) 1 and 2, 5.8S and 28S ribosomal RNA ofAncylostomaspp. andUncinaria stenocephalawere performed, and hookworm species were identified by PCR-restriction fragment length polymorphism (RFLP) or DNA sequencing. Hookworm eggs were detected by microscopy in 490/1621 (30.23%, 95% CI 28.01–32.54) faecal samples. Estimates of faecal prevalence were high in counties receiving higher rainfall (Narok 46.80%, Meru 44.88%) and low in those with a more arid climate (Isiolo 19.73%, Turkana 11.83%). In a subset of 70 faecal samples,Ancylostoma caninum(n = 59) was the most common species, followed byA. braziliense(n = 10) andA.cf.duodenale(n = 1). This study reports for the first time the detection ofA.cf.duodenalein dog faeces and zoonotic hookworm species in Kenyan dogs. These findings emphasize the need for control measures such as enforcing laws for restraining stray dogs, regular deworming of dogs, and public health awareness programmes aimed at informing communities on outdoor use of footwear.

Anthroponotic transmission of Cryptosporidium parvum predominates in countries with poorer sanitation: a systematic review and meta-analysis

Background

Globally cryptosporidiosis is one of the commonest causes of mortality in children under 24 months old and may be associated with important longterm health effects. Whilst most strains of Cryptosporidium parvum are zoonotic, C. parvum IIc is almost certainly anthroponotic. The global distribution of this potentially important emerging infection is not clear.

Methods

We conducted a systematic review of papers identifying the subtype distribution of C. parvum infections globally. We searched PubMed and Scopus using the following key terms Cryptospor* AND parvum AND (genotyp* OR subtyp* OR gp60). Studies were eligible for inclusion if they had found C. parvum within their human study population and had subtyped some or all of these samples using standard gp60 subtyping. Pooled analyses of the proportion of strains being of the IIc subtype were determined using StatsDirect. Meta-regression analyses were run to determine any association between the relative prevalence of IIc and Gross Domestic Product, proportion of the population with access to improved drinking water and improved sanitation.

Results

From an initial 843 studies, 85 were included in further analysis. Cryptosporidium parvum IIc was found in 43 of these 85 studies. Across all studies the pooled estimate of relative prevalence of IIc was 19.0% (95% CI: 12.9–25.9%), but there was substantial heterogeneity. In a meta-regression analysis, the relative proportion of all C. parvum infections being IIc decreased as the percentage of the population with access to improved sanitation increased and was some 3.4 times higher in those studies focussing on HIV-positive indivduals.

Conclusions

The anthroponotic C. parvum IIc predominates primarily in lower-income countries with poor sanitation and in HIV-positive individuals. Given the apparent enhanced post-infectious virulence of the other main anthroponotic species of Cryptosporidium (C. hominis), it is important to learn about the impact of this subtype on human health.

Electronic supplementary material

The online version of this article (10.1186/s13071-018-3263-0) contains supplementary material, which is available to authorized users.

Profiling the diversity of Cryptosporidium species and genotypes in wastewater treatment plants in Australia using next generation sequencing

Wastewater recycling is an increasingly popular option in worldwide to reduce pressure on water supplies due to population growth and climate change. Cryptosporidium spp. are among the most common parasites found in wastewater and understanding the prevalence of human-infectious species is essential for accurate quantitative microbial risk assessment (QMRA) and cost-effective management of wastewater. The present study conducted next generation sequencing (NGS) to determine the prevalence and diversity of Cryptosporidium species in 730 raw influent samples from 25 Australian wastewater treatment plants (WWTPs) across three states: New South Wales (NSW), Queensland (QLD) and Western Australia (WA), between 2014 and 2015. All samples were screened for the presence of Cryptosporidium at the 18S rRNA (18S) locus using quantitative PCR (qPCR), oocyst numbers were determined directly from the qPCR data using DNA standards calibrated by droplet digital PCR, and positives were characterized using NGS of 18S amplicons. Positives were also screened using C. parvum and C. hominis specific qPCRs. The overall Cryptosporidium prevalence was 11.4% (83/730): 14.3% (3/21) in NSW; 10.8% (51/470) in QLD; and 12.1% (29/239) in WA. A total of 17 Cryptosporidium species and six genotypes were detected by NGS. In NSW, C. hominis and Cryptosporidium rat genotype III were the most prevalent species (9.5% each). In QLD, C. galli, C. muris and C. parvum were the three most prevalent species (7.7%, 5.7%, and 4.5%, respectively), while in WA, C. meleagridis was the most prevalent species (6.3%). The oocyst load/Litre ranged from 70 to 18,055 oocysts/L (overall mean of 3426 oocysts/L: 4746 oocysts/L in NSW; 3578 oocysts/L in QLD; and 3292 oocysts/L in WA). NGS-based profiling demonstrated that Cryptosporidium is prevalent in the raw influent across Australia and revealed a large diversity of Cryptosporidium species and genotypes, which indicates the potential contribution of livestock, wildlife and birds to wastewater contamination.

Zoonotic Helminth Diseases in Dogs and Dingoes Utilising Shared Resources in an Australian Aboriginal Community

The impacts of free-roaming canids (domestic and wild) on public health have long been a concern in Australian Indigenous communities. We investigated the prevalence of zoonotic helminth diseases in dogs and sympatric dingoes, and used radio telemetry to measure their spatial overlap, in an Aboriginal community in the Wet Tropics of Australia. Samples collected from dingoes and dogs showed high levels of infection with the zoonotic hookworm, Ancylostoma caninum. Dingoes were also positive for A. ceylanicum infection (11.4%), but dogs were infection free. Whipworm, Trichuris vulpis, infection was far more prevalent in necropsies of domestic dogs (78.6%) than dingoes (3.7%). Dogs were free from Dirofilaria immitis infection, while dingoes recorded 46.2% infection. Eleven dingoes and seven free-roaming domestic dogs were fitted with Global Positioning System collars and tracked over an extended period. Dingo home-ranges almost completely overlapped those of the domestic dogs. However, dingoes and dogs did not utilise the same area at the same time, and dogs may have avoided dingoes. This spatial overlap in resource use presents an opportunity for the indirect spill-over and spill-back of parasites between dogs and dingoes. Tracking and camera traps showed that the community rubbish tip and animal carcasses were areas of concentrated activity for dogs and dingoes.

Comparison of three cryptosporidiosis outbreaks in Western Australia: 2003, 2007 and 2011

Cryptosporidium is a protozoan parasite that causes the diarrhoeal disease, cryptosporidiosis. Although many species have been identified, the majority of human disease worldwide is caused by two species; Cryptosporidium parvum and Cryptosporidium hominis. In Australia, data from the National Notifiable Diseases Surveillance System (NNDSS) show that cryptosporidiosis outbreaks occur every few years. To better understand the transmission, trends and nature of cryptosporidiosis outbreaks in Western Australia, epidemiological and genomic data from three cryptosporidiosis outbreaks in 2003, 2007 and 2011 were reviewed. The 2007 outbreak was the largest (n = 607) compared with the outbreaks in 2003 (n = 404) and 2011 (n = 355). All three outbreaks appeared to have occurred predominantly in the urban metropolitan area (Perth), which reported the highest number of case notifications; increases in case notifications were also observed in rural and remote areas. Children aged 0-4 years and non-Aboriginal people comprised the majority of notifications in all outbreaks. However, in the 2003 and 2007 outbreaks, a higher proportion of cases from Aboriginal people was observed in the remote areas. Molecular data were only available for the 2007 (n = 126) and 2011 (n = 42) outbreaks, with C. hominis the main species identified in both outbreaks. Subtyping at the glycoprotein 60 (gp60) locus identified subtype IbA10G2 in 46.3% and 89.5% of C. hominis isolates typed, respectively, in the 2007 and 2011 outbreaks, with the IdA15G1 subtype was identified in 33.3% of C. hominis isolates typed in the 2007 outbreak. The clustering of cases with the IdA15G1 subtype in the remote areas suggests the occurrence of a concurrent outbreak in remote areas during the 2007 outbreak, which primarily affected Aboriginal people. Both the C. hominis IbA10G2 and IdA15G1 subtypes have been implicated in cryptosporidiosis outbreaks worldwide; its occurrence indicates that the mode of transmission in both the 2007 and 2011 outbreaks was anthroponotic. To better understand the epidemiology, sources and transmission of cryptosporidiosis in Australia, genotyping data should routinely be incorporated into national surveillance programmes.

Cryptosporidium species and subtypes in animals inhabiting drinking water catchments in three states across Australia

As part of long-term monitoring of Cryptosporidium in water catchments serving Western Australia, New South Wales (Sydney) and Queensland, Australia, we characterised Cryptosporidium in a total of 5774 faecal samples from 17 known host species and 7 unknown bird samples, in 11 water catchment areas over a period of 30 months (July 2013 to December 2015). All samples were initially screened for Cryptosporidium spp. at the 18S rRNA locus using a quantitative PCR (qPCR). Positives samples were then typed by sequence analysis of an 825 bp fragment of the 18S gene and subtyped at the glycoprotein 60 (gp60) locus (832 bp). The overall prevalence of Cryptosporidium across the various hosts sampled was 18.3% (1054/5774; 95% CI, 17.3-19.3). Of these, 873 samples produced clean Sanger sequencing chromatograms, and the remaining 181 samples, which initially produced chromatograms suggesting the presence of multiple different sequences, were re-analysed by Next- Generation Sequencing (NGS) to resolve the presence of Cryptosporidium and the species composition of potential mixed infections. The overall prevalence of confirmed mixed infection was 1.7% (98/5774), and in the remaining 83 samples, NGS only detected one species of Cryptosporidium. Of the 17 Cryptosporidium species and four genotypes detected (Sanger sequencing combined with NGS), 13 are capable of infecting humans; C. parvum, C. hominis, C. ubiquitum, C. cuniculus, C. meleagridis, C. canis, C. felis, C. muris, C. suis, C. scrofarum, C. bovis, C. erinacei and C. fayeri. Oocyst numbers per gram of faeces (g^-1) were also determined using qPCR, with medians varying from 6021-61,064 across the three states. The significant findings were the detection of C. hominis in cattle and kangaroo faeces and the high prevalence of C. parvum in cattle. In addition, two novel C. fayeri subtypes (IVaA11G3T1 and IVgA10G1T1R1) and one novel C. meleagridis subtype (IIIeA18G2R1) were identified. This is also the first report of C. erinacei in Australia. Future work to monitor the prevalence of Cryptosporidium species and subtypes in animals in these catchments is warranted.

Ancylostoma ceylanicum, novel etiological agent for traveler's diarrhea-report of four Japanese patients who returned from Southeast Asia and Papua New Guinea

Background

Countries in the Southeast Asia region have a high prevalence of soil-transmitted helminth, such as roundworm, whipworm, and hookworms [Ancylostoma duodenale, Necator americanus, Ancylostoma ceylanicum]. Recent molecular-based surveys have revealed that A. ceylanicum, a zoonotic hookworm, is likely the second most prevalent hookworm species infecting humans in that part of the world, while others have noted that this infection is an emerging public health risk not only for indigenous people but also for visitors from other countries.

Case presentation

We recently encountered four cases of A. ceylanicum infection in Japanese individuals who returned from Southeast Asia and Papua New Guinea. Case 1 was a 25-year-old male who stayed in a rainforest in Malaysia for 4 weeks, where he developed abdominal pain and diarrhea in the third week. Eleven adult worms (five males, six females) were expelled after treatment with pyrantel pamoate and identified as A. ceylanicum based on morphological characteristics and DNA sequences of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene. Case 2 was a 26-year-old male who spent 2 years as an overseas cooperation volunteer for agriculture in Papua New Guinea. He did not note any symptoms at that time, though eggs were detected in feces samples at a medical check-up examination after returning. Although collection of adult worms was unsuccessful, DNA analysis of the eggs for cox1 and the ribosomal internal transcribed spacer (ITS)-1 and ITS-2 genes demonstrated that they were A. ceylanicum. Case 3 was a 47-year-old male who spent 1 month in a rural village in Lao People's Democratic Republic and began suffering from watery diarrhea from the third week. A total of nine adult worms (three males, six females) were collected by endoscopic procedures and following treatment with pyrantel pamoate. Morphological examination and molecular analyses of the cox1 gene showed that they were A. ceylanicum. Case 4 was a 27-year-old male who participated in group travel to India for 5 days. Three weeks after returning, he developed abdominal pain and diarrhea. Hookworm eggs were found in feces samples and developed into larvae in culture, which were identified as A. ceylanicum based on molecular analysis of the cox1 gene. Eosinophilia was observed in all of the cases prior to treatment.

Conclusions

A. ceylanicum should be recognized as an important etiologic pathogen of hookworm diseases in travelers to countries in the Southeast Asia and West Pacific Ocean regions.

Ancylostoma ceylanicum Hookworm in the Solomon Islands

Although hookworm is highly prevalent in the Solomon Islands, the species involved are unknown. We initiated this study in response to finding Ancylostoma ceylanicum hookworm in a peacekeeper in Australia who had returned from the Solomon Islands. Kato-Katz fecal surveys performed in 2013 and 2014 in 2 village groups in East Malaita, Solomon Islands, identified hookworm-positive samples. These specimens were tested by cytochrome oxidase 1 (cox-1) gene multiplex PCR and sequenced. Of 66 positive specimens, 54 (81.8%) contained only Necator americanus, 11 (16.7%) contained only A. ceylanicum, and 1 (1.5%) contained both species. A. duodenale was not found. Haplotype analysis of cox-1 sequences placed all human isolates (99% bootstrap support) of A. ceylanicum within the zoonotic clade rather than the human-specific clade. This study confirms that A. ceylanicum is endemic in the East Malaita region of this Pacific Island nation. The strain of the A. ceylanicum in this region can be shared among humans, dogs, and cats.

First detection and genetic characterisation of Enterocytozoon bieneusi in wild deer in Melbourne's water catchments in Australia

BACKGROUND

Enterocytozoon bieneusi is reported to be a common microsporidian of humans and animals in various countries. However, E. bieneusi has yet to be recorded in animals in Australia. Here, we undertook the first molecular epidemiological investigation of E. bieneusi in three species of deer (Cervus elaphus, Dama dama and Rusa unicolor) that live in the catchment areas that supply the city of Melbourne with drinking water.

METHODS

Genomic DNA was extracted from a total of 610 individual faecal samples from wild deer, including sambar deer (Rusa unicolor) (n = 516), red deer (Cervus elaphus) (n = 77) and fallow deer (Dama dama) (n = 17) from nine catchment areas, and then tested using a nested PCR-based sequencing approach employing internal transcribed spacer (ITS) of nuclear ribosomal DNA as the genetic marker.

RESULTS

Enterocytozoon bieneusi was detected in 25 of all 610 (4.1%) samples exclusively in samples from sambar deer. The analysis of ITS sequence data revealed three known (D, J and Type IV) and two new (MWC_d1 and MWC_d2) genotypes of E. bieneusi. Although the significance of the latter two new genotypes is presently unknown, phylogenetic analysis of ITS sequence data sets showed that they cluster with genotypes D and Type IV, which have been recorded previously in humans. These findings suggest that sambar deer in the water catchments harbour zoonotic genotypes of E. bieneusi.

CONCLUSIONS

Further insight into the epidemiology of E. bieneusi in wildlife, water and the environment in Australia will be important to have an informed position on the public health significance of microsporidiosis caused by this microbe.

A Survey of Intestinal Parasites of Domestic Dogs in Central Queensland

Australia has a very high rate of dog ownership, which in some circumstances may lead to exposure to zoonotic parasitic diseases from those companion animals. Domestic dog faecal samples (n = 300) were collected from public spaces and private property in the greater Rockhampton (Central Queensland) region and tested for intestinal helminths and protozoa by direct microscopy, two flotation methods and a modified acid-fast stain for cryptosporidia. Intestinal parasites detected included hookworms (25%), Cystoisospora ohioensis complex (9%), Blastocystis hominis (3%), Giardia duodenalis (3%), Spirometra erinacei (1%) and Toxocara canis (1%), Sarcocystis spp. (2%), Cryptosporidium spp. (2%) and Cystoisospora canis (1%). One infection each with Trichuris vulpis, Dipylidium caninum and a protozoa belonging to the Entamoeba histolytica complex were identified. Sheather's sucrose centrifugal flotation was more sensitive than saturated salt passive flotation, but no single test detected all cases of parasitic infection identified. The test methodologies employed are poor at recovering larva of Strongyloides stercoralis, Aleurostrongylus abstrussis and eggs of cestodes such as Echinococcus granulosis, so the potential presence of these parasites in Central Queensland domestic dogs cannot be excluded by this survey alone.

More bark than bite: Comparative studies are needed to determine the importance of canine zoonoses in Aboriginal communities. A critical review of published research

The objective of this review was to identify and critique over forty years of peer-reviewed literature concerned with the transmission of canine zoonoses to Aboriginal people and determine the zoonotic organisms documented in dogs in Australian Aboriginal communities. A systematic literature search of public health, medical and veterinary databases identified 19 articles suitable for critical appraisal. Thirteen articles documented the occurrence of recognized zoonotic organisms in dogs in Aboriginal communities, including Toxocara canis, Dirofilaria immitis, Streptococcus dysgalactiae, Rickettsia felis, Sarcoptes scabiei and Giardia. Currently, there is definitive evidence indicating that dogs act as a reservoir for human scabies in Aboriginal communities. However, there is a need for large-scale, high-quality, comparative studies of dogs and humans from the same household to assess the occurrence and importance of transmission of S. scabiei and other diseases between dogs and humans. These studies should use current genetic and molecular techniques along with traditional techniques to identify and type organisms in order to better understand their epidemiology. This review has revealed that there is a lack of high-quality comparative studies to determine whether dogs are contributing to human disease by transmitting zoonoses. Our recommendations differ significantly from current public health policy and may have substantial implications for human and dog health.

Soil-Transmitted Helminths in Tropical Australia and Asia

Soil-transmitted helminths (STH) infect 2 billion people worldwide including significant numbers in South-East Asia (SEA). In Australia, STH are of less concern; however, indigenous communities are endemic for STH, including Strongyloides stercoralis, as well as for serious clinical infections due to other helminths such as Toxocara spp. The zoonotic hookworm Ancylostoma ceylanicum is also present in Australia and SEA, and may contribute to human infections particularly among pet owners. High human immigration rates to Australia from SEA, which is highly endemic for STH Strongyloides and Toxocara, has resulted in a high prevalence of these helminthic infections in immigrant communities, particularly since such individuals are not screened for worm infections upon entry. In this review, we consider the current state of STH infections in Australia and SEA.

Use of a bioinformatic-assisted primer design strategy to establish a new nested PCR-based method for Cryptosporidium

BACKGROUND

The accurate tracking of Cryptosporidium in faecal, water and/or soil samples in water catchment areas is central to developing strategies to manage the potential risk of cryptosporidiosis transmission to humans. Various PCR assays are used for this purpose. Although some assays achieve specific amplification from Cryptosporidium DNA in animal faecal samples, some do not. Indeed, we have observed non-specificity of some oligonucleotide primers in the small subunit of nuclear ribosomal RNA gene (SSU), which has presented an obstacle to the identification and classification of Cryptosporidium species and genotypes (taxa) from faecal samples.

RESULTS

Using a novel bioinformatic approach, we explored all available Cryptosporidium genome sequences for new and diagnostically-informative, multi-copy regions to specifically design oligonucleotide primers in the large subunit of nuclear ribosomal RNA gene (LSU) as a basis for an effective nested PCR-based sequencing method for the identification and/or classification of Cryptosporidium taxa.

CONCLUSION

This newly established PCR, which has high analytical specificity and sensitivity, is now in routine use in our laboratory, together with other assays developed by various colleagues. Although the present bioinformatic workflow used here was for the specific design of primers in nuclear DNA of Cryptosporidium, this approach should be broadly applicable to many other microorganisms.

Differences in the occurrence and epidemiology of cryptosporidiosis in Aboriginal and non-Aboriginal people in Western Australia (2002-2012)

Cryptosporidiosis is a diarrhoeal illness caused by the protozoan parasite Cryptosporidium. In Australia, very little is known about the epidemiology of cryptosporidiosis in Aboriginal peoples. The present study analysed long-term cryptosporidiosis patterns across Western Australia (WA) (2001-2012), combined with genotyping and subtyping data at the 18S and glycoprotein 60 (gp60) loci respectively. Comparison of cryptosporidiosis notifications between Aboriginal and non-Aboriginal people in WA, revealed that notification rates among Aboriginal people were up to 50 times higher compared to non-Aboriginal people, highlighting the burden of the disease in this population. More than 90% of notifications were in Aboriginal children aged 00-04years, who had a notification rate 20.5 times higher than non-Aboriginal children in the same age group. Cryptosporidium hominis was the predominant species infecting both Aboriginal and non-Aboriginal people. However, Aboriginal people were mainly infected with the C. hominis IdA15G1 subtype, whereas non-Aboriginal people were predominantly infected with the IbA10G2 subtype. To control cryptosporidiosis in Aboriginal populations in Australia, effective health interventions/promotions need to be a priority for public health research and action.

Rodents as a reservoir of infection caused by multiple zoonotic species/genotypes of C. parvum, C. hominis, C. suis, C. scrofarum, and the first evidence of C. muskrat genotypes I and II of rodents in Europe

Cryptosporidium spp. is an important causative agent of intestinal parasitoses-induced diarrhoea in humans and animals worldwide. Rodents (small mammals), the main reservoir of infections, are globally expanded and overpopulated, which increases the risk of transfer of human and zoonotic pathogens from the genus Cryptosporidium. In this study, Cryptosporidium was detected in wild immunocompetent asymptomatic small mammals. Altogether 262 fecal samples were collected from five areas in Eastern Slovakia from four different rodent species (Myodes glareolus, Apodemus agrarius, Apodemus flavicollis, Rattus norvegicus), eight samples originated from two insectivore species (Sorex araneus, Crocidura suaveolens), and two sample from a carnivore Mustela nivalis. The samples were examined using a method modified in our laboratory, based on the use of specific primers on a small subunit rRNA (18S rRNA) gene for species identification, and amplification of GP60 gene coding 60-kDa glycoprotein for genotype determination. The following species were identified: Cryptosporidium parvum (n=15), genotypes IIaA18G3R1 (n=11; KU311673), IIaA10G1R1 (n=1; KU311670), IIcA5G3a (n=1; KU311669), IIiA10 (n=2; KU311672); Cryptosporidium suis (n=4; KU311671); Cryptosporidium scrofarum (n=28); Cryptosporidium environment sp. (n=12; KU311677); Cryptosporidium muskrat genotype I (n=3; KU311675); Cryptosporidium muskrat genotype II (n=3; KU311676). From one of the rodent, the species Cryptosporidium hominis genotype IbA10G2 (KU311668) was identified for the first time. The results of this study indicate low host specificity of the detected Cryptosporidium species and imply the importance of free-living small mammals in urban and suburban habitats as a potential source of human cryptosporidiosis.

The hookworm Ancylostoma ceylanicum: An emerging public health risk in Australian tropical rainforests and Indigenous communities

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.

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Ancylostoma ceylanicum is the common hookworm of domestic dogs and cats throughout Asia.

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A. ceylanicum is an emerging public health risk in tropical northern Australia.

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A first time account of A. ceylanicum infection in domestic dogs in an Indigenous community.

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A. ceylanicum was present in soil samples from two out of three popular tourist locations sampled.

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Dogs may be a public health risk to Indigenous communities and tourists in the Wet Tropics.

Cryptosporidium spp. and Giardia spp. in feces and water and the associated exposure factors on dairy farms

The aims of this study were to verify the prevalence of Cryptosporidium spp. and Giardia spp. in animal feces and drinking water on dairy farms and to identify a possible relation between the exposure factors and the presence of these parasites. Fecal samples from cattle and humans and water samples were collected on dairy farms in Paraná, Brazil. Analysis of (oo)cysts in the feces was performed by the modified Ziehl-Neelsen staining and centrifugal flotation in zinc sulfate. Test-positive samples were subjected to nested PCR amplification of the 18SSU ribosomal RNA gene for identification of Cryptosporidium and Giardia and of the gp60 gene for subtyping of Cryptosporidium. Microbiological analysis of water was carried out by the multiple-tube method and by means of a chromogenic substrate, and parasitological analysis was performed on 31 samples by direct immunofluorescence and nested PCR of the genes mentioned above. Identification of the species of Cryptosporidium was performed by sequencing and PCR with analysis of restriction fragment length polymorphisms. The prevalence of Giardia and Cryptosporidium was higher in calves than in adults. Among the samples of cattle feces, Cryptosporidium parvum was identified in 41 (64%), C. ryanae in eight (12.5%), C. bovis in four (6.3%), C. andersoni in five (7.8%), and a mixed infection in 20 samples (31.3%). These parasites were not identified in the samples of human feces. Thermotolerant coliform bacteria were identified in 25 samples of water (45.5%). Giardia duodenalis and C. parvum were identified in three water samples. The gp60 gene analysis of C. parvum isolates revealed the presence of two strains (IIaA20G1R1 and IIaA17G2R2) in the fecal samples and one (IIaA17G2R1) in the water samples. The presence of coliforms was associated with the water source, structure and degradation of springs, rain, and turbidity. The prevalence of protozoa was higher in calves up to six months of age. C. parvum and G. duodenalis were identified in the water of dairy farms, as were thermotolerant coliforms; these findings point to the need for guidance on handling of animals, preservation of water sources, and water treatment.

First survey of Cryptosporidium, Giardia and Enterocytozoon in diarrhoeic children from Wuhan, China

Intestinal protozoan pathogens cause significant diarrhoeal diseases in children. However, to date, there has been limited genetic study of the intestinal pathogens Cryptosporidium, Giardia and Enterocytozoon in humans in China, with the exception of research in a small number of cities/provinces. In the present study, PCR-based tools were used to detect and characterise these protistan parasites from 500 children with a history of diarrhoea in Wuhan and environs, Hubei province, China. Genomic DNAs from faecal samples were screened for the particular protists by PCR utilising regions in the small subunit (SSU) of the nuclear ribosomal RNA, the 60kDa glycoprotein (gp60), the internal transcribed spacer of nuclear ribosomal DNA (ITS) and/or the triose phosphate isomerase (tpi) genes as markers. Cryptosporidium meleagridis subtype IIIb (10/500, 2.0%), Giardia duodenalis assemblage A (7/500, 1.4%) and Enterocytozoon bieneusi genotype D (1/500, 0.2%) were identified in small percentages of the 500 samples. No significant gender- or age-associated differences in the prevalence of Cryptosporidium and Giardia infections were found. Future studies might focus on the occurrence of these protists in children as well as animals, with an emphasis on Cryptosporidium meleagridis in pets and agriculturally important birds, in different parts of Hubei province.

Zoonotic Cryptosporidium Species in Animals Inhabiting Sydney Water Catchments

Cryptosporidium is one of the most common zoonotic waterborne parasitic diseases worldwide and represents a major public health concern of water utilities in developed nations. As animals in catchments can shed human-infectious Cryptosporidium oocysts, determining the potential role of animals in dissemination of zoonotic Cryptosporidium to drinking water sources is crucial. In the present study, a total of 952 animal faecal samples from four dominant species (kangaroos, rabbits, cattle and sheep) inhabiting Sydney's drinking water catchments were screened for the presence of Cryptosporidium using a quantitative PCR (qPCR) and positives sequenced at multiple loci. Cryptosporidium species were detected in 3.6% (21/576) of kangaroos, 7.0% (10/142) of cattle, 2.3% (3/128) of sheep and 13.2% (14/106) of rabbit samples screened. Sequence analysis of a region of the 18S rRNA locus identified C. macropodum and C. hominis in 4 and 17 isolates from kangaroos respectively, C. hominis and C. parvum in 6 and 4 isolates respectively each from cattle, C. ubiquitum in 3 isolates from sheep and C. cuniculus in 14 isolates from rabbits. All the Cryptosporidium species identified were zoonotic species with the exception of C. macropodum. Subtyping using the 5' half of gp60 identified C. hominis IbA10G2 (n = 12) and IdA15G1 (n = 2) in kangaroo faecal samples; C. hominis IbA10G2 (n = 4) and C. parvum IIaA18G3R1 (n = 4) in cattle faecal samples, C. ubiquitum subtype XIIa (n = 1) in sheep and C. cuniculus VbA23 (n = 9) in rabbits. Additional analysis of a subset of samples using primers targeting conserved regions of the MIC1 gene and the 3' end of gp60 suggests that the C. hominis detected in these animals represent substantial variants that failed to amplify as expected. The significance of this finding requires further investigation but might be reflective of the ability of this C. hominis variant to infect animals. The finding of zoonotic Cryptosporidium species in these animals may have important implications for the management of drinking water catchments to minimize risk to public health.

A Case of Ancylostoma ceylanicum Infection Occurring in an Australian Soldier Returned from Solomon Islands

A 26-year-old male member of the Australian Defense Force presented with a history of central abdominal pain of 4 weeks duration and peripheral eosinophilia consistent with eosinophilic enteritis. Acute hookworm disease was diagnosed as the cause. Adult worms recovered from feces after therapy with albendazole were morphologically consistent with Ancylostoma ceylanicum. As the patient had been deployed with the Regional Assistance Mission to Solomon Islands for 6 months prior to this presentation, it is very likely that the A. ceylanicum was acquired in Solomon Islands. Until now, it has been assumed that any Ancylostoma spp. recovered from humans in Solomon Islands is A. duodenale. However, this case demonstrates that human hookworm infection acquired in the Solomon Islands could be caused by A. ceylanicum.

PCR-RFLP method to detect zoonotic and host-specific Giardia duodenalis assemblages in dog fecal samples

Giardia duodenalis is a zoonotic protozoan that parasitizes the upper small intestine of human and many mammals including dogs. To develop a restriction fragment length polymorphism (RFLP) method for typing zoonotic (A, B) and host-specific (C, D) assemblages of G. duodenalis from dog, β-giardin gene was amplified with design primer pairs B3 and B4. The PCR products were digested with restriction enzyme Afa I and Msp I; then, PCR-RFLP method was compared with HRM genotyping and sequencing method for G. duodenalis from dog. The results showed that each of assemblages A-D had unique restriction pattern, which was consistent with the predictive results. Among 21 samples tested by PCR-RFLP, 1 human-derived and 8 dog-derived G. duodenalis were identified as assemblage A; 5 dog-derived G. duodenalis as assemblage C; 7 dog-derived G. duodenalis as assemblage D, which were coincided with the HRM genotyping and sequencing results. It is concluded that the PCR-RFLP is quick, easy, and accurate method for the sequence typing of G. duodenalis zoonotic and specific assemblages from dogs.

Genetic analysis of Giardia and Cryptosporidium from people in Northern Australia using PCR-based tools

To date, there has been limited genetic study of the gastrointestinal pathogens Giardia and Cryptosporidium in northern parts of Australia. Here, PCR-based methods were used for the genetic characterization of Giardia and Cryptosporidium from 695 people with histories of gastrointestinal disorders from the tropical North of Australia. Genomic DNAs from fecal samples were subjected to PCR-based analyses of regions from the triose phosphate isomerase (tpi), small subunit (SSU) of the nuclear ribosomal RNA and/or the glycoprotein (gp60) genes. Giardia and Cryptosporidium were detected in 13 and four of the 695 samples, respectively. Giardia duodenalis assemblages A and B were found in 4 (31%) and 9 (69%) of the 13 samples in persons of <9 years of age. Cryptosporidium hominis (subgenotype IdA18), Cryptosporidium mink genotype (subgenotype IIA16R1) and C. felis were also identified in single patients of 11-21 years of age. Future studies might focus on a comparative study of these and other protists in rural communities in Northern Australia.

Development of a rapid HRM genotyping method for detection of dog-derived Giardia lamblia

Giardia lamblia is a zoonotic flagellate protozoan in the intestine of human and many mammals including dogs. To assess a threat of dog-derived G. lamblia to humans, the common dog-derived G. lamblia assemblages A, C, and D were genotyped by high-resolution melting (HRM) technology. According to β-giardin gene sequence, the qPCR-HRM primers BG5 and BG7 were designed. A series of experiments on the stability, sensitivity, and accuracy of the HRM method were also tested. Results showed that the primers BG5 and BG7 could distinguish among three assemblages A, C, and D, which Tm value differences were about 1 °C to each other. The melting curves of intra-assay reproducibility were almost coincided, and those of inter-assay reproducibility were much the same shape. The lowest detection concentration was about 5 × 10(-6)-ng/μL sample. The genotyping results from 21 G. lamblia samples by the HRM method were in complete accordance with sequencing results. It is concluded that the HRM genotyping method is rapid, stable, specific, highly sensitive, and suitable for clinical detection and molecular epidemiological survey of dog-derived G. lamblia.

Intestinal parasites of children and adults in a remote Aboriginal community of the Northern Territory, Australia, 1994-1996

INTRODUCTION

Parasitic infections can adversely impact health, nutritional status and educational attainment. This study investigated hookworm and other intestinal parasites in an Aboriginal community in Australia from 1994 to 1996.

METHODS

Seven surveys for intestinal parasites were conducted by a quantitative formol-ether method on faecal samples. Serological testing was conducted for Strongyloides stercoralis and Toxocara canis IgG by enzyme-linked immunosorbent assays.

RESULTS

Of the 314 participants, infections were as follows: Trichuris trichiura (86%); hookworm, predominantly Ancylostoma duodenale (36%); Entamoeba spp. (E. histolytica complex [E. histolytica, E. dispar and E. moskovski], E. coli and E. hartmanni) (25%); S. stercoralis (19%); Rodentolepis nana (16%); and Giardia duodenalis (10%). Serological diagnosis for 29 individuals showed that 28% were positive for S. stercoralis and 21% for T. canis. There was a decrease in the proportion positive for hookworm over the two-year period but not for the other parasite species. The presence of hookworm, T. trichiura and Entamoeba spp. was significantly greater in 5-14 year olds (n = 87) than in 0-4 year olds (n = 41), while the presence of S. stercoralis, R. nana, G. duodenalis and Entamoeba spp. in 5-14 year olds was significantly greater than 15-69 year olds (n = 91).

DISCUSSION

Faecal testing indicated a very high prevalence of intestinal parasites, especially in schoolchildren. The decrease in percentage positive for hookworm over the two years was likely due to the albendazole deworming programme, and recent evidence indicates that the prevalence of hookworm is now low. However there was no sustained decrease in percentage positive for the other parasite species.

First genetic analysis of Cryptosporidium from humans from Tasmania, and identification of a new genotype from a traveller to Bali

Little is known about the molecular composition of Cryptosporidium species from humans living in the insular state of Tasmania, Australia. In the present study, we genetically characterized 82 samples of Cryptosporidium from humans following conventional coproscopic testing in a routine, diagnostic laboratory. Using a PCR-coupled single-strand conformation polymorphism (SSCP) technique, targeting portions of the small subunit rRNA (SSU), and 60 kDa glycoprotein (gp60) loci, we identified two species of Cryptosporidium, including C. hominis (subgenotypes IbA10G2, IdA16, IeA12G3T3, and IfA19G1) and C. parvum (IIaA16G1R1 and IIaA18G3), and a new operational taxonomic unit (OTU) that genetically closely resembled C. wrairi. This OTU was further characterized using markers in the actin, Cryptosporidium oocyst wall protein (COWP), and 70 kDa heat shock protein (hsp70) genes. This study provides the first characterization of species and genotypes of Cryptosporidium from Tasmania, and presents clear genetic evidence, using five independent genetic loci, for a new genotype or species of Cryptosporidium in a Tasmanian person with a recent history of travelling to Bali, Indonesia. It would be interesting to undertake detailed molecular-based studies of Cryptosporidium in Indonesia and neighbouring countries, in conjunction with morphological and experimental investigations of new genotypes.

Zoonotic Ancylostoma ceylanicum infection detected by endoscopy

We report a case of Ancylostoma ceylanicum infection detected by endoscopy. It was diagnosed and confirmed using polymerase chain reaction (PCR) and DNA sequencing. The patient is a 58-year-old Malaysian woman who lives in a rural area, where uncontrolled populations of stray and semidomesticated dogs live in close proximity with humans.