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Pathogens (Basel, Switzerland) Oct 2023Studying parasitic nematodes, which generate a massive hazard to animal health, is more difficult than studying free-living nematodes as appropriate animal models are...
Studying parasitic nematodes, which generate a massive hazard to animal health, is more difficult than studying free-living nematodes as appropriate animal models are essential, and the relationship between parasites and hosts is extremely complex. is an intestinal nematode parasite that mainly infects dogs, humans and other primates. Currently, worms needed for research mainly rely on their natural host, the dog. This study explored a method of using as a model for The immunosuppressed were infected with . subcutaneously, and post-parasitic, first-stage larvae (PP L1) were detected in the faeces, with more larvae in female gerbils. In addition, parasitic females (PFs), third-stage larvae (L3s) and rhabditiform larvae were found primarily in the small intestines and lungs of infected gerbils. The PFs and auto-infective third-stage larvae (aL3s) obtained from are morphologically identical to those obtained from beagles and . Moreover, the infection of caused changes to biochemical indicators in the serum and in the physiology of . The results demonstrated that can be infected by , and this model provides a great tool for exploring the biological processes of this parasite and its interaction with the host.
PubMed: 38003750
DOI: 10.3390/pathogens12111285 -
Pathogens (Basel, Switzerland) May 2020infection in immunocompromised subjects, including chronic alcoholics, can lead to a severe disease. Moreover, its prevalence in alcoholic patients seems to be higher...
infection in immunocompromised subjects, including chronic alcoholics, can lead to a severe disease. Moreover, its prevalence in alcoholic patients seems to be higher than that in the general population. The aims of this study were to evaluate the frequency of infection in alcoholic patients and to investigate the influence of alcohol intake on the parasite load, as well as to evaluate the sensitivity of three different parasitological methods according to the larval output. Fecal samples of 1290 chronic alcoholic patients were examined by spontaneous sedimentation, Baermann-Moraes, and agar plate culture (APC) methods. was the most frequent parasite found (14.5%; n = 187). Alcoholic individuals infected with had a higher daily consumption of alcohol than those who were not infected, 528.6 and 403.0 g/day, respectively (p < 0.05). In addition, individuals with higher alcohol intake presented an increase in parasite load. The diagnostic method with the highest sensitivity was APC, 97.9% (183/187). In conclusion, seems to be the most frequent parasite found in alcoholic individuals from endemic areas and alcohol intake is positively associated with larvae output. In addition, this study confirms that APC is the most sensitive parasitological method used for diagnosis.
PubMed: 32481753
DOI: 10.3390/pathogens9060422 -
Open Forum Infectious Diseases 2017We report the rare finding of rhabditiform larvae in biliary fluid, here associated with cholecystitis and near total portal vein thrombosis. The role of leading to...
We report the rare finding of rhabditiform larvae in biliary fluid, here associated with cholecystitis and near total portal vein thrombosis. The role of leading to atypical clinical presentations and difficulty diagnosing strongyloidiasis in such patients with appropriate geographic exposure is discussed.
PubMed: 29181423
DOI: 10.1093/ofid/ofx217 -
Philosophical Transactions of the Royal... Jan 2024The epidemiology of is briefly reviewed with an emphasis on cross section and longitudinal studies of infection prevalence stratified by age, performance of different...
The epidemiology of is briefly reviewed with an emphasis on cross section and longitudinal studies of infection prevalence stratified by age, performance of different diagnostic tools, mass drug administration (MDA) impact and estimates of key population parameters within the complex life cycle of the parasite that determine transmission intensity and response to control measures. The paucity of studies is highlighted, and gaps in current knowledge identified about the population biology of this very prevalent infection in tropical and sub-tropical regions around the world. A stochastic individual based stochastic model is described in part to highlight gaps in knowledge. The impact of repeated MDA is simulated to illustrate some aspects of transmission dynamics of this helminth infection. Specifically, the impact and bounce back times in either the intervals between treatment rounds, or post the cessation of treatment, depend critically on the magnitude of two distinct components of the basic reproductive number . The absence of data on these key components is highlighted, as is the value of studies of longitudinal cohorts of people in regions of endemic infection post rounds of MDA to record how infection levels bounce back post treatment at individual and population levels of study. This article is part of the Theo Murphy meeting issue ': omics to worm-free populations'.
Topics: Animals; Humans; Strongyloides stercoralis; Strongyloidiasis; Mass Drug Administration; Prevalence; Basic Reproduction Number
PubMed: 38008114
DOI: 10.1098/rstb.2022.0442 -
International Journal of Infectious... Nov 2020To provide a spatial risk assessment for the neglected disease strongyloidiasis in the United States by prioritizing areas with high probability of Strongyloides...
OBJECTIVES
To provide a spatial risk assessment for the neglected disease strongyloidiasis in the United States by prioritizing areas with high probability of Strongyloides stercoralis presence and to offer recommendations for targeted screening and surveillance.
METHODS
The risk assessment was based on a species distribution model with parasite occurrence data and ecologically important environmental variables as input and local habitat suitability for the species as output. The model used a maximum entropy algorithm and occurrence records and environmental data from public sources. This ecological risk assessment was coupled to socioeconomic factors using multi-criteria analysis.
RESULTS
The model predicts suitable habitat for the parasite in ten states beyond the southeastern United States where it has been recorded including states in the south, east and northeast, and west coasts.
CONCLUSIONS
We recommend strongyloidiasis should be reportable in 16 states at high risk and uniform, near universal solid organ transplant screening should be implemented alongside approaches to heighten clinical suspicion.
Topics: Animal Distribution; Animals; Ecosystem; Humans; Mass Screening; Models, Biological; Risk Assessment; Strongyloides stercoralis; Strongyloidiasis; United States
PubMed: 32896663
DOI: 10.1016/j.ijid.2020.09.002 -
PLoS Neglected Tropical Diseases Jan 2020Severe Strongyloides stercoralis infection in kidney transplant recipients is associated with considerable morbidity and mortality, although little is known about the...
BACKGROUND
Severe Strongyloides stercoralis infection in kidney transplant recipients is associated with considerable morbidity and mortality, although little is known about the risk factors for such infection.
METHODOLOGY/PRINCIPAL FINDINGS
This was a retrospective, multicenter, case-control study in which we assessed the risk factors for and clinical outcomes of severe S. stercoralis infections in kidney transplant recipients in Brazil. We included 138 kidney transplant recipients: 46 cases and 92 controls. Among the cases, the median number of days from transplantation to diagnosis was 117 (interquartile range [IQR], 73.5-965) and the most common clinical findings were gastrointestinal symptoms (in 78.3%) and respiratory symptoms (in 39.1%), whereas fever and eosinophilia were seen in only 32.6% and 43.5%, respectively. The 30-day all-cause mortality among the cases was 28.3% overall and was significantly higher among the cases of infection occurring within the first three months after transplantation (47% vs. 17.2%, P = 0.04). The independent risk factors were receiving a transplant from a deceased donor (odds ratio [OR] = 6.16, 95% confidence interval [CI] = 2.05-18.5), a history of bacterial infection (OR = 3.04, 95% CI = 1.2-7.5), and a cumulative corticosteroid dose (OR = 1.005, 95% CI = 1.001-1.009). The independent predictors of mortality were respiratory failure (OR = 98.33, 95% CI = 4.46-2169.77) and concomitant bacteremia (OR = 413.00, 95% CI = 4.83-35316.61).
CONCLUSIONS/SIGNIFICANCE
Severe S. stercoralis infections are associated with considerable morbidity and mortality after kidney transplantation. In endemic areas, such infection may occur late after transplantation, although it seems to be more severe when it occurs earlier after transplantation. Specific risk factors and clinical manifestations can identify patients at risk, who should receive prophylaxis or early treatment.
Topics: Adolescent; Adrenal Cortex Hormones; Adult; Animals; Bacterial Infections; Brazil; Case-Control Studies; Humans; Immunocompromised Host; Kidney Transplantation; Retrospective Studies; Risk Factors; Strongyloides stercoralis; Strongyloidiasis; Tissue Donors; Young Adult
PubMed: 32004346
DOI: 10.1371/journal.pntd.0007998 -
Parasites & Vectors Jan 2021Strongyloidiasis, one of the neglected tropical diseases (NTDs), can be fatal in immunocompromised patients. Available data on Strongyloides stercoralis infection in...
BACKGROUND
Strongyloidiasis, one of the neglected tropical diseases (NTDs), can be fatal in immunocompromised patients. Available data on Strongyloides stercoralis infection in high-risk patients in Iran are limited. The aim of the present study was to determine the prevalence of S. stercoralis infection and associated risk factors among high-risk patients as well as to evaluate the sensitivity of the diagnostic tests used in the diagnose of S. stercoralis infection.
METHODS
This cross-sectional study was performed from 2019 to 2020 among 300 high-risk patients in Khuzestan Province, southwestern Iran. Patients with autoimmune diseases, uncontrolled diabetes, HIV/AIDS, cancer, organ transplant, hematological malignancy, asthma and chronic obstructive pulmonary disease (COPD) were examined using direct smear examination, formalin-ether concentration, Baermann funnel technique, agar plate culture, and ELISA test. Since agar plate culture was considered the reference diagnostic test, culture-positive samples were confirmed by PCR amplification and the sequencing of the nuclear 18S rDNA (SSU) hypervariable region (HVRIV) of the parasite.
RESULTS
The prevalence of S. stercoralis infection was 1%, 1.3%, 2%, 2.7%, and 8.7% using direct smear examination, formalin-ether concentration, Baermann funnel technique, agar plate culture, and ELISA test, respectively. All culture-positive samples were confirmed by SSU-PCR. According to the results, the most sensitive test was ELISA, with 100% sensitivity, followed by the Baermann funnel technique with the sensitivity of 75%. Direct smear examination, formalin-ether concentration technique, and Baermann funnel technique had the highest PPV (100%) while the ELISA test had the highest NPV (100%). Significant eosinophilia was observed in the patients whose culture test was positive (7/8; P < 0.05). In the present study, the majority of the positive cases by the agar plate culture had a history of prolonged exposure to soil and of asthma and COPD and were > 60 years old.
CONCLUSIONS
Given that the ELISA test had the highest NPV, the screening of all high-risk patients for S. stercoralis infection in endemic areas is recommended prior to starting corticosteroid therapy with the ELISA test. The results indicate the importance of paying attention to patients with unknown eosinophilia in endemic areas. Ivermectin should be available to strongyloidiasis patients in the endemic areas.
Topics: Adult; Animals; Asthma; Cross-Sectional Studies; Diagnostic Tests, Routine; Enzyme-Linked Immunosorbent Assay; Feces; Female; Formaldehyde; Humans; Immunocompromised Host; Iran; Ivermectin; Male; Mass Screening; Middle Aged; Polymerase Chain Reaction; Prevalence; Pulmonary Disease, Chronic Obstructive; Risk Factors; Soil; Strongyloides stercoralis; Strongyloidiasis; Young Adult
PubMed: 33422116
DOI: 10.1186/s13071-020-04549-6 -
The American Journal of Tropical... Aug 2019affects 30-100 million people worldwide. The burden is underestimated because of the paucity of studies, limited geographical areas surveyed, and poor quality of...
affects 30-100 million people worldwide. The burden is underestimated because of the paucity of studies, limited geographical areas surveyed, and poor quality of diagnostic tests. This study aimed at determining the epidemiology of strongyloidiasis using sensitive microscopy testing in rural populations living at different altitudes in Cusco, Peru. Data were collected from subjects aged > 3 years living in Quellouno (elevation 2,600 ft) and Limatambo (elevation 8,379 ft) districts. Subjects provided one fresh stool sample and answer a standardized questionnaire. Fresh stool was tested on site using the Baermann's test and agar plate culture. Formalin-preserved stool was tested by rapid sedimentation. Eighty percent (585/715) of eligible subjects consented to participate; after excluding subjects with missing data, 65% (462/715) were included. Fifty-five percentage were female; the median age was 33 years (interquartile range 13-52), and 72% had government health insurance. Half had intestinal parasites, and was the most common (24.5%) followed by (15.5%), (14.9%), and hookworm (11.5%). The agar plate culture detected more cases of than Baermann's or sedimentation tests. infection was more common at low altitude (26.4%) than at high altitude (18.6%), but the difference was not statistically significant ( = 0.08). Older age, walking barefoot, bathing in rivers/streams, and using municipal sewage were associated with strongyloidiasis. was the most prevalent parasite in the areas studied and was associated with demographic, socioeconomic, and sanitary factors.
Topics: Adolescent; Adult; Altitude; Animals; Cross-Sectional Studies; Feces; Female; Humans; Intestinal Diseases, Parasitic; Male; Middle Aged; Peru; Prevalence; Risk Factors; Rural Population; Strongyloides stercoralis; Strongyloidiasis; Young Adult
PubMed: 31264557
DOI: 10.4269/ajtmh.18-0568 -
PLoS Neglected Tropical Diseases Apr 2023Human infection with the intestinal nematode Strongyloides stercoralis is persistent unless effectively treated, and potentially fatal in immunosuppressed individuals....
Human infection with the intestinal nematode Strongyloides stercoralis is persistent unless effectively treated, and potentially fatal in immunosuppressed individuals. Epidemiological data are lacking, partially due to inadequate diagnosis. A rapid antigen detection test is a priority for population surveillance, validating cure after treatment, and for screening prior to immunosuppression. We used a targeted analysis of open access 'omics' data sets and used online predictors to identify S. stercoralis proteins that are predicted to be present in infected stool, Strongyloides-specific, and antigenic. Transcriptomic data from gut and non-gut dwelling life cycle stages of S. stercoralis revealed 328 proteins that are differentially expressed. Strongyloides ratti proteomic data for excreted and secreted (E/S) proteins were matched to S. stercoralis, giving 1,057 orthologues. Five parasitism-associated protein families (SCP/TAPS, prolyl oligopeptidase, transthyretin-like, aspartic peptidase, acetylcholinesterase) were compared phylogenetically between S. stercoralis and outgroups, and proteins with least homology to the outgroups were selected. Proteins that overlapped between the transcriptomic and proteomic datasets were analysed by multiple sequence alignment, epitope prediction and 3D structure modelling to reveal S. stercoralis candidate peptide/protein coproantigens. We describe 22 candidates from seven genes, across all five protein families for further investigation as potential S. stercoralis diagnostic coproantigens, identified using open access data and freely-available protein analysis tools. This powerful approach can be applied to many parasitic infections with 'omic' data to accelerate development of specific diagnostic assays for laboratory or point-of-care field application.
Topics: Animals; Humans; Strongyloides stercoralis; Strongyloidiasis; Proteomics; Acetylcholinesterase; Strongyloides ratti; Feces
PubMed: 37068106
DOI: 10.1371/journal.pntd.0010777 -
Parasites & Vectors May 2022Strongyloides stercoralis is endemic in tropical and subtropical regions, but reports of infections in central and northern Europe have been recently increasing....
BACKGROUND
Strongyloides stercoralis is endemic in tropical and subtropical regions, but reports of infections in central and northern Europe have been recently increasing. Infections occur mainly in humans and dogs. In dogs, both dog-adapted and zoonotic S. stercoralis genotypes seem to occur. Clinical manifestations mainly include gastrointestinal and respiratory signs. The severity of the disease can vary greatly and depends on the immune status of the host. The infection is potentially fatal in immunosuppressed individuals, either medically induced or due to an underlying disease, in which hyperinfections and disseminated infections with extraintestinal parasite dissemination may occur.
METHODS
Diagnosis was based on coproscopy, including flotation and the Baermann funnel technique, histology of small intestinal biopsies and molecular analysis of mitochondrial cytochrome oxidase subunit I (COI) and hypervariable regions I and IV (HVR I and HVR IV) of the nuclear 18S rDNA loci.
RESULTS
Two independent cases of severe canine S. stercoralis infection in Austria are presented. In both cases, S. stercoralis was detected in histological sections of the small intestine and with the Baermann funnel technique. Molecular analysis revealed strains with zoonotic potential. Case 1 was a 1-year-old female French bulldog with a long history of respiratory and gastrointestinal signs, severe emaciation and apathy before S. stercoralis infection was diagnosed. Treatment with moxidectin (2.5 mg/kg body weight [BW], oral route) did not eliminate the infection, but treatment with ivermectin (0.2 mg/kg BW, subcutaneously) was successful. Case 2 consisted of two 2-month-old Pomeranian puppies, one female and one male, from a litter of four, which died soon after presenting dyspnoea and haemorrhagic diarrhoea (female) or torticollis (male); S. stercoralis infection was first diagnosed post-mortem.
CONCLUSION
More attention should be paid to this nematode because although it appears to be rare in Austria, it is easily overlooked on standard coproscopy unless a Baermann funnel technique is used, and even then, it can be missed. Moxidectin is not always successful in eliminating the infection, and treatment with ivermectin should be considered in cases of infection.
Topics: Animals; Austria; Dog Diseases; Dogs; Feces; Female; Ivermectin; Male; Strongyloides stercoralis; Strongyloidiasis
PubMed: 35570317
DOI: 10.1186/s13071-022-05270-2