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Infection, Genetics and Evolution :... Nov 2021Genetic variation in pathogen populations provides the means to answer questions in disease ecology and transmission, illuminating interactions between genetic traits,... (Review)
Review
Genetic variation in pathogen populations provides the means to answer questions in disease ecology and transmission, illuminating interactions between genetic traits, environmental exposures, and disease. Such studies elucidate the phylogeny, evolution, transmission and pathogenesis of viruses, bacteria and parasites. Here, we review how such studies have fostered understanding of the biology and epidemiology of zoonotic nematode parasites in the genus Trichinella spp., which impose considerable economic and health burdens by infecting wildlife, livestock, and people. To use such data to define ongoing chains of local transmission and source traceback, researchers first must understand the extent and distribution of genetic variation resident in regional parasite populations. Thus, genetic variability illuminates a population's past as well as its present. Here we review how such data have helped define population dynamics of Trichinella spp. in wild and domesticated hosts, creating opportunities to harness genetic variation in the quest to prevent, track, and contain future outbreaks.
Topics: Animals; Evolution, Molecular; Humans; Molecular Epidemiology; Trichinella; Trichinellosis
PubMed: 34509647
DOI: 10.1016/j.meegid.2021.105080 -
Veterinary Medicine and Science Nov 2022Investigating the global epidemiological patterns of Trichinella in pigs is required for accurate recognition and to establishing proper control programmes and... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Investigating the global epidemiological patterns of Trichinella in pigs is required for accurate recognition and to establishing proper control programmes and preventive measures, as well as to decrease human exposure.
OBJECTIVES
To obtain a better understanding of the global prevalence of Trichinella in domestic pigs and factors that might influence the prevalence, a systematic review and meta-analysis was performed.
METHODS
The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. Multiple databases were used to identify literature published between January 2000 and December 2021, representing studies from 1985 to 2021, on Trichinella prevalence in domestic pigs. Prevalence was calculated on a global and country level, by country Human Development Index (HDI), climate, pig management system, and diagnostic test.
RESULTS
The global pooled prevalence based on 60 manuscripts representing 32 countries and 65 pig populations was 2.02% (95% confidence interval [CI]: 0.88-3.62) and the estimated pooled prevalence in different continents ranged from 0.00% to 11.8%. Trichinella was highest in low HDI countries (21.6%; 95% CI: 4.3-47.2), tropical wet climates (20.9%; 95% CI: 10.3-34.1), and non-intensive pig farming systems (6.1%; 95% CI: 1.0-15.5).
CONCLUSIONS
While there were regional differences in Trichinella prevalence in domestic pigs, these were likely driven by country HDI and pig farming systems versus climatic factors. Increased biosecurity in outdoor pig production systems, focused meat inspections and promoting awareness could potentially decrease risk of infection.
Topics: Humans; Swine; Animals; Trichinella; Trichinellosis; Prevalence; Swine Diseases; Sus scrofa
PubMed: 36137293
DOI: 10.1002/vms3.951 -
Anti-cancer Agents in Medicinal... 2018Conventional therapeutic strategies for tumors have had limited success, and innovative and more effective approaches to treatment are urgently required. The ancient... (Review)
Review
BACKGROUND
Conventional therapeutic strategies for tumors have had limited success, and innovative and more effective approaches to treatment are urgently required. The ancient idea that various biological, bacterial, yeast, viral, and parasitic agents can be used as cancer therapeutics has gradually attracted considerable interest. Certain parasites have been widely discussed in association with human and animal tumors. The purpose of this review was to examine previous literatures which investigates the relations between Trichinella spiralis (T. spiralis) and tumors.
METHODS
Using PubMed, articles published before 2018 in the whole world have been searched and comprehensively reviewed.
RESULTS
Many researches have provided proofs that T. spiralis possesses antitumor activities. The antitumor effect of T. spiralis was first described in the 1970s. However, its research has been inconsistent, and little progress has been made in this field. Therefore, the mechanisms underlying these inhibitory effects are still unclear, and convincing evidence of the links between T. spiralis and the prevention or treatment of tumors from clinical trials is absent. Meanwhile, some other researches also suggested that T. spiralis may cause or contribute to coinfection with a tumors.
CONCLUSION
The review has highlighted the scientific literature focussing on evidence for T. spiralis to act as a pro- or antitumorigenic agent is summarized and discussed, in hope of contributing to a better understanding of the relations between T. spiralis and tumors.
Topics: Animals; Antineoplastic Agents; Cell Proliferation; Humans; Neoplasms; Trichinella spiralis
PubMed: 29173187
DOI: 10.2174/1871520617666171121115847 -
Annals of Parasitology 2018This review summarizes known data on the species composition of nematodes in 24 species of rodents inhabiting the territory of Armenia (South of Lesser Caucasus). The... (Review)
Review
This review summarizes known data on the species composition of nematodes in 24 species of rodents inhabiting the territory of Armenia (South of Lesser Caucasus). The studied rodents include members of some cosmopolitan species (Mus musculus, Rattus norvegicus, Rattus rattus), as well as endemic and narrow-areal species (Meriones vinogradovi, Spermophilus xanthoprymnus, Microtus schidlovskii, Mesocricetus brandti, Sciurus anomalus). The taxonomical identity of the nematode species reported by previous authors is discussed with regard to present knowledge about helminth fauna of rodents. Our review concludes that 34 nematode species are present in rodents in Armenia, five of which are identified for the first time in rodents from the territory of Armenia, and three of which (Trichinella spiralis, Trichostrongylus colubriformis, Trichostrongylus skrjabini) are able to parasitize humans.
Topics: Animals; Armenia; Gerbillinae; Humans; Mice; Nematoda; Rats; Sciuridae; Trichinella spiralis
PubMed: 30316207
DOI: 10.17420/ap6403.148 -
Veterinary Parasitology, Regional... Jul 2021Trichinella spp. infect wild carnivores throughout the world. We determined the prevalence and mean infection intensity of Trichinella spp. in bobcats (Lynx rufus) from...
Trichinella spp. infect wild carnivores throughout the world. We determined the prevalence and mean infection intensity of Trichinella spp. in bobcats (Lynx rufus) from 41 counties in Oklahoma (USA). Tongues from 306 bobcats were examined using artificial tissue digestion. The prevalence (95% confidence interval) of Trichinella spp. was 5.9% (3.7%-9.2%) in which 18 of the 301 bobcats were infected. Bobcats infected with Trichinella spp. were detected in 10 of the 41 (24.4%; 13.7%-39.5%) counties sampled. Although variable, a statistically significant difference was not detected in the prevalence of Trichinella spp. among counties where bobcats were collected. The mean (standard deviation) and median (range) infection intensity of Trichinella sp. larvae were 30.9 (39.8) and 9.6 (0.6-119.9) larvae per gram of tissue examined. Genotyping results demonstrated that 17 bobcats were infected with T. murrelliand one bobcat was infected with T. pseudospiralis. This is the first report of T. pseudospiralis in bobcats and in Oklahoma. These data suggest the bobcat, as an obligate carnivore, is likely an important host in maintaining T. murrelli sylvatic cycles in Oklahoma.
Topics: Animals; Carnivora; Lynx; Oklahoma; Trichinella; Trichinellosis
PubMed: 34474802
DOI: 10.1016/j.vprsr.2021.100609 -
PloS One 2022Trichinellosis is a zoonotic disease caused by the ingestion of the Trichinella nematode. With a worldwide incidence of approximately 10,000 cases per year, Trichinella...
Trichinellosis is a zoonotic disease caused by the ingestion of the Trichinella nematode. With a worldwide incidence of approximately 10,000 cases per year, Trichinella spiralis is responsible for most human infections. There are no specific signs or symptoms of this parasitic infection. Muscle biopsy is the gold diagnostic standard for trichinellosis, but the technique is invasive and unable to detect the early stage of infection. Although immunodiagnostics are also available, antibody detection usually occurs after 3 weeks and prolonged up to 19 years after the acute phase. Therefore, additional diagnostic biomarkers must be identified to improve trichinellosis diagnosis. This study aimed to measure concentration changes in mouse serum proteins prior to T. spiralis infection and 2, 4 and 8 weeks after infection, and to identify T. spiralis circulating proteins and antigens using mass spectrometry-based proteomics. Mouse muscle-related proteins including inter-alpha-trypsin inhibitor heavy chain H2, a protein involved in the response to muscle tissue damage, were up-regulated in mouse sera during the T. spiralis larvae invasion. Additionally, 33 circulatory parasite proteins were identified in infected mouse sera. Notably, T. spiralis long-chain fatty acid transport protein 1 could be detected in the early stage of infection and peroxidasin-like protein was identified 2, 4 and 8 weeks after infection. Seventeen T. spiralis circulating antigens were detected in mouse immune complexes, with PX domain protein being found 2, 4 and 8 weeks after infection. Because peroxidasin-like protein and PX domain protein were detected at all post-infection time points, sequence alignments of these proteins were performed, which showed they are conserved among Trichinella spp. and have less similarity to the human and murine sequences. Integrative analysis of T. spiralis biomarkers throughout the course of infection may reveal additional diagnostic targets to improve early diagnosis of trichinellosis.
Topics: Animals; Antibodies, Helminth; Antigens, Helminth; Enzyme-Linked Immunosorbent Assay; Helminth Proteins; Larva; Mice; Muscle Proteins; Trichinella; Trichinella spiralis; Trichinellosis
PubMed: 35271623
DOI: 10.1371/journal.pone.0265013 -
Brain Pathology (Zurich, Switzerland) Jan 1997Trichinosis is a worldwide zoonotic disease closely related to cultural and dietary habits caused by a nematode Trichinella spp. Human infection is acquired through...
Trichinosis is a worldwide zoonotic disease closely related to cultural and dietary habits caused by a nematode Trichinella spp. Human infection is acquired through ingestion of undercooked meat containing infective encysted larvae. There are two cycles of transmission, one domestic and the other wild. A complete life cycle develops in a single host harboring adult worms in the small intestine, from which newborn larvae migrate and finally encyst in striated muscle. Traumatic and immunological alterations are responsible for the main clinical features, including diarrhea, febrile syndrome, myalgias, oculopalpebral signs and eosinophilia. Cardiovascular, lung and CNS involvement characterize severe trichinosis. CNS inflammatory infiltration and damage may result from larval migration and vascular obstruction, or from the effect of toxic parasite antigens, or eosinophil infiltration. Humoral and cellular immune host response are relevant both to protect against re-infection and for immunodiagnosis. DNA probes and PCR technology may help to identify Trichinella spp. Muscle biopsy may disclose T spiralis larvae coiled within a muscle fibre host nurse cell surrounded by a capsule. Inflammatory infiltration includes monocytes, plasma cells, eosinophils and T lymphocytes mainly of the suppressor/cytotoxic phenotype. Histological appearance and histochemical profile of the host nurse cell differ from that of striated muscle fibre and are partly indicative of regeneration. Our own histological and histochemical findings in experimental studies of infected mouse muscle support the concept that changes induced by the larva encysting within a single host skeletal muscle fibre which becomes a nurse cell are unique of Trichinella infection. Interestingly, no dystrophin could be detected within the host nurse cell-capsule interface. It has been advanced that larva-induced host muscle fibre changes may be regulated at muscle gene transcription level whilst host regulatory pathways governed by cell cycle phase may also contribute to larval development.
Topics: Animals; Biopsy; Central Nervous System Diseases; Host-Parasite Interactions; Humans; Larva; Muscles; Trichinella; Trichinellosis; Zoonoses
PubMed: 9034572
DOI: 10.1111/j.1750-3639.1997.tb01081.x -
WormBook : the Online Review of C.... Nov 2006Clade I nematode species in the genus Trichinella can cause infections in humans that lead to mortality and serious morbidity. There are currently eight recognized... (Review)
Review
Clade I nematode species in the genus Trichinella can cause infections in humans that lead to mortality and serious morbidity. There are currently eight recognized species or genotypes that comprise this genus. The species display diverse biological characteristics, the evolutionary significance of which recently has been extensively clarified. Some of that diversity translates into variable importance as zoonotic pathogens, with T. spiralis having the highest significance. Trichinellosis has re-emerged as an important zoonotic infection in various parts of the world, reminding us that control of this infection depends on persistent vigilance. Trichinella species display unique and biologically interesting complexity in interactions with host cells that they inhabit. Significant progress has been made toward understanding details of these interactions. Progress on transcriptomics, proteomics and now genomics offers exciting prospects for accelerating advances in future research. An overview of these parasites regarding biology, significance as zoonotic pathogens and selected research topics is presented here.
Topics: Animals; Genome, Helminth; Host-Parasite Interactions; Humans; Trichinella spiralis; Trichinellosis
PubMed: 18050431
DOI: 10.1895/wormbook.1.124.1 -
Parasite (Paris, France) 2020Knowledge on the epidemiology, host range and transmission of Trichinella spp. infections in different ecological zones in southern Africa including areas of... (Review)
Review
Epidemiology and hypothetical transmission cycles of Trichinella infections in the Greater Kruger National Park of South Africa: an example of host-parasite interactions in an environment with minimal human interactions.
Knowledge on the epidemiology, host range and transmission of Trichinella spp. infections in different ecological zones in southern Africa including areas of wildlife-human interface is limited. The majority of reports on Trichinella infections in sub-Saharan Africa were from wildlife resident in protected areas. Elucidation of the epidemiology of the infections and the prediction of hosts involved in the sylvatic cycles within specific ecological niches is critical. Of recent, there have been reports of Trichinella infections in several wildlife species within the Greater Kruger National Park (GKNP) of South Africa, which has prompted the revision and update of published hypothetical transmission cycles including the hypothetical options based previously on the biology and feeding behaviour of wildlife hosts confined to the GKNP. Using data gathered from surveillance studies and reports spanning the period 1964-2019, confirmed transmission cycles and revised hypothesized transmission cycles of three known Trichinella species (T. zimbabwensis, Trichinella T8 and T. nelsoni) are presented. These were formulated based on the epidemiological factors, feeding habits of hosts and prevalence data gathered from the GKNP. We presume that the formulated sylvatic cycles may be extrapolated to similar national parks and wildlife protected areas in sub-Saharan Africa where the same host and parasite species are known to occur. The anecdotal nature of some of the presented data confirms the need for more intense epidemiological surveillance in national parks and wildlife protected areas in the rest of sub-Saharan Africa to unravel the epidemiology of Trichinella infections in these unique and diverse protected landscapes.
Topics: Animals; Animals, Wild; Ecology; Host Specificity; Host-Parasite Interactions; Humans; Parks, Recreational; South Africa; Trichinella; Trichinellosis
PubMed: 32163031
DOI: 10.1051/parasite/2020010 -
Veterinary Parasitology Nov 2016Publication of the genome from the clade I organism, Trichinella spiralis, has provided us an avenue to address more holistic problems in parasitology; namely the...
Publication of the genome from the clade I organism, Trichinella spiralis, has provided us an avenue to address more holistic problems in parasitology; namely the processes of adaptation and the evolution of parasitism. Parasitism among nematodes has evolved in multiple, independent events. Deciphering processes that drive species diversity and adaptation are keys to understanding parasitism and advancing control strategies. Studies have been put forth on morphological and physiological aspects of parasitism and adaptation in nematodes; however, data is now coming available to investigate adaptation, host switching and parasitism at the genomic level. Herein we compare proteomic data from the clade I parasite, Trichinella spiralis with data from Brugia malayi (clade III), Meloidogyne hapla and Meloidogyne incognita (clade IV), and free-living nematodes belonging to the genera Caenorhabditis and Pristionchus (clade V). We explore changes in protein family birth/death and expansion/reduction over the course of metazoan evolution using Homo sapiens, Drosophila melanogaster and Saccharomyces cerevisiae as outgroups for the phylum Nematoda. We further examine relationships between these changes and the ability and/or result of nematodes adapting to their environments. Data are consistent with gene loss occurring in conjunction with nematode specialization resulting from parasitic worms acclimating to well-defined, environmental niches. We observed evidence for independent, lateral gene transfer events involving conserved genes that may have played a role in the evolution of nematode parasitism. In general, parasitic nematodes gained proteins through duplication and lateral gene transfer, and lost proteins through random mutation and deletions. Data suggest independent acquisition rather than ancestral inheritance among the Nematoda followed by selective gene loss over evolutionary time. Data also show that parasitism and adaptation affected a broad range of proteins, especially those involved in sensory perception, metabolism, and transcription/translation. New protein gains with functions related to regulating transcription and translation, and protein family expansions with functions related to morphology and body development have occurred in association with parasitism. Further gains occurred as a result of lateral gene transfer and in particular, with the cyanase protein family In contrast, reductions and/or losses have occurred in protein families with functions related to metabolic process and signal transduction. Taking advantage of the independent occurrences of parasitism in nematodes, which enabled us to distinguish changes associated with parasitism from species specific niche adaptation, our study provides valuable insights into nematode parasitism at a proteome level using T. spiralis as a benchmark for early adaptation to or acquisition of parasitism.
Topics: Adaptation, Physiological; Animals; Biological Evolution; Genome, Helminth; Genomics; Nematoda; Phylogeny; Proteomics; Trichinella spiralis
PubMed: 27425574
DOI: 10.1016/j.vetpar.2016.07.003