Strongyloidiasis is caused by the human infective nematodes Strongyloides stercoralis, Strongyloides fuelleborni subsp. fuelleborni and Strongyloides fuelleborni subsp. kellyi. The zoonotic potential ...of S. stercoralis and the potential role of dogs in the maintenance of strongyloidiasis transmission has been a topic of interest and discussion for many years. In Australia, strongyloidiasis is prevalent in remote socioeconomically disadvantaged communities in the north of the continent. Being an isolated continent that has been separated from other regions for a long geological period, description of diversity of Australian Strongyloides genotypes adds to our understanding of the genetic diversity within the genus. Using PCR and amplicon sequencing (Illumina sequencing technology), we sequenced the Strongyloides SSU rDNA hyper-variable I and hyper-variable IV regions using Strongyloides-specific primers, and a fragment of the mtDNA cox1 gene using primers that are broadly specific for Strongyloides sp. and hookworms. These loci were amplified from DNA extracted from Australian human and dog faeces, and one human sputum sample. Using this approach, we confirm for the first time that potentially zoonotic S. stercoralis populations are present in Australia, suggesting that dogs represent a potential reservoir of human strongyloidiasis in remote Australian communities.
Is strongyloidiasis a zoonosis from dogs? Bradbury, Richard S.; Streit, Adrian
Philosophical transactions of the Royal Society of London. Series B. Biological sciences,
01/2024, Letnik:
379, Številka:
1894
Journal Article
Recenzirano
Strongyloides stercoralis
infection remains a major veterinary and public health challenge globally. This chronic and potentially lifelong disease has fatal outcomes in immunosuppressed people and ...dogs. Currently, the role of dogs in the transmission cycle of human strongyloidiasis remains enigmatic. While zoonotic transmission to humans from companion animals has been proposed, this has not been confirmed. Modern molecular methods have allowed greater opportunity to explore the genotypes of
S. stercoralis
in dogs and humans. Work thus far has demonstrated that at least two distinct lineages exist, one apparently confined to canine hosts and one found in canine, feline, human and non-human primate hosts. Although genotyping of dog and human isolates from the same village has demonstrated identical genotypes in both species, coprophagia of human waste by dogs confounds interpretation. It remains unclear if dogs act as a zoonotic reservoir for human infection, or vice versa, or if this occurs only in some regions of the world and not in others. These questions must be answered before effective control strategies for strongyloidiasis can be instituted. This review explores the evidence for and against cross-species transmission of
S. stercoralis
between dogs and humans and summarizes future directions for research in this area.
This article is part of the Theo Murphy meeting Issue ‘
Strongyloides
: omics to worm-free populations’.
Etymologia: Pseudoterranova decipiens Partin, William C.; Bradbury, Richard S.
Emerging infectious diseases,
11/2022, Letnik:
28, Številka:
11
Journal Article
Recenzirano
Odprti dostop
A compelling but overlooked nautical provenance for the etymology of this genus existed, which prompted Scott Norton of Georgetown University and David Gibson from the Natural History Museum in ...London, to gently and cleverly advise that “someone literally missed the boat.” In 1914, Atkinson, and London School of Tropical Medicine parasitologist Robert Thomson Leiper named this nematode Terranova Antarctica in honor of the RRS Terra Nova. Google Scholar Mattiucci S, Nascetti G. Advances and trends in the molecular systematics of anisakid nematodes, with implications for their evolutionary ecology and host-parasite co-evolutionary processes.
A fecal survey in Tamil Nadu, India, revealed 2 persons passed schistosome eggs, later identified as Schistosoma incognitum, a parasite of pigs, dogs, and rats. We investigated those cases and ...reviewed autochthonous schistosomiasis cases from India and Nepal. Whether the 2 new cases represent true infection or spurious passage is undetermined.
Pathogen Genomics in Public Health Armstrong, Gregory L; MacCannell, Duncan R; Taylor, Jill ...
The New England journal of medicine,
12/2019, Letnik:
381, Številka:
26
Journal Article
Recenzirano
Odprti dostop
The development of next-generation sequencing technology has had a major effect on a wide range of infectious diseases that affect public health. Next-generation sequencing promises to facilitate the ...diagnosis of outbreaks, the detection of drug resistance, and the selection of vaccine approaches and has many other applications.
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.
Strongyloidiasis is a World Health Organization neglected tropical disease usually caused by
, a parasitic worm with a complex life cycle. Globally, 300-600 million people are infected through ...contact with fecally contaminated soil. An autoinfective component of the life cycle can lead to chronic infection that may be asymptomatic or cause long-term symptoms, including malnourishment in children. Low larval output can limit the sensitivity of detection in stool, with serology being effective but less sensitive in immunocompromise. Host immunosuppression can trigger catastrophic, fatal hyperinfection/dissemination, where large numbers of larvae pierce the bowel wall and disseminate throughout the organs. Stable disease is effectively treated by single-dose ivermectin, with disease in immunocompromised patients treated with multiple doses. Strategies for management include raising awareness, clarifying zoonotic potential, the development and use of effective diagnostic tests for epidemiological studies and individual diagnosis, and the implementation of treatment programs with research into therapeutic alternatives and medication safety.
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•A comprehensive summary of Strongyloides genotyping studies to date is provided.•Host specificity, reproduction pattern and phylogeny may be elucidated by genotyping.•Former and ...current approaches to the genotyping of Strongyloides spp. are reviewed.•Genotyping has improved our understanding of Strongyloides population genetics.•Insights arising about the role of dogs as potential reservoirs of human Strongyloides stercoralis infection are discussed.
Strongyloidiasis represents a major medical and veterinary helminthic disease. Human infection is caused by Strongyloides stercoralis, Strongyloides fuelleborni fuelleborni and Strongyloides fuelleborni kellyi, with S.stercoralis accounting for the majority of cases. Strongyloides f. fuelleborni likely represents a zoonosis acquired from non-human primates (NHPs), while no animal reservoir for S. f. kellyi infection has been found. Whether S. stercoralis represents a zoonosis acquired from dogs and cats remains unanswered. Over the past two decades various tools have been applied to genotype Strongyloides spp. The most commonly sequenced markers have been the hyper-variable regions I and IV of the 18S rRNA gene and selected portions of the cytochrome c oxidase subunit I gene. These markers have been sequenced and compared in Strongyloides from multiple hosts and geographical regions. More recently, a machine learning algorithm multi-locus sequence typing approach has been applied using these markers, while others have applied whole genome sequencing. Genotyping of Strongyloides from dogs, cats, NHPs and humans has identified that S. stercoralis likely originated in dogs and adapted to human hosts. It has also been demonstrated that S. stercoralis is distinct from S. f. fuelleborni and S. f. kellyi. Two distinct genetic clades of S. stercoralis exist, one restricted to dogs and another infecting humans, NHPs, dogs and cats. Genotyping of S. f. fuelleborni has identified two separate clades, one associated with African isolates and another Indochinese peninsular clade. This review summarises the history and development of genotyping tools for Strongyloides spp. It describes the findings of major studies to date in the context of the epidemiology and evolutionary biology of these helminths, with a specific focus on human-infecting species.
has one of the most complex life cycles of the human-infecting nematodes. A common misconception in medical and public health professions is that
in its biology is akin to other intestinal nematodes, ...such as the hookworms. Despite original evidence provided by medical and veterinary research about this unique helminth, many assumptions have entered the scientific literature. This helminth is set apart from others that commonly affect humans by (a) the internal autoinfective cycle with autoinfective larvae randomly migrating through tissue, parthenogenesis, and the potential for lifelong infection in the host, the profound pathology occurring in hyperinfection and systemic manifestations of strongyloidiasis, and (b) a limited external cycle with a single generation of free-living adults. This paper aims to review and discuss original research on the unique life cycle of
that distinguishes it from other helminths and highlight areas where increased understanding of the parasite's biology might lead to improved public health prevention and control strategies.
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