Observation of the Free-living Adults of Strongyloides stercoralis from a Human Stool in Korea

2009 ◽  
Vol 41 (2) ◽  
pp. 105 ◽  
Author(s):  
Young-Hee Hong ◽  
Jong-Wan Kim ◽  
In-Soo Rheem ◽  
Jae-Soo Kim ◽  
Suk-Bae Kim ◽  
...  
Keyword(s):  
Strongyloides Stercoralis ◽  
Free Living ◽  
Human Stool

scholarly journals Chemosensory mechanisms of host seeking and infectivity in skin-penetrating nematodes

2020 ◽  
Vol 117 (30) ◽  
pp. 17913-17923 ◽  
Author(s):  
Spencer S. Gang ◽  
Michelle L. Castelletto ◽  
Emily Yang ◽  
Felicitas Ruiz ◽  
Taylor M. Brown ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Strongyloides Stercoralis ◽  
Sensory Cues ◽  
Ancylostoma Ceylanicum ◽  
Free Living ◽  
Infective Larvae ◽  
Host Seeking ◽  
Third Stage ◽  
Olfactory Preferences ◽  
Insight Into

Approximately 800 million people worldwide are infected with one or more species of skin-penetrating nematodes. These parasites persist in the environment as developmentally arrested third-stage infective larvae (iL3s) that navigate toward host-emitted cues, contact host skin, and penetrate the skin. iL3s then reinitiate development inside the host in response to sensory cues, a process called activation. Here, we investigate how chemosensation drives host seeking and activation in skin-penetrating nematodes. We show that the olfactory preferences of iL3s are categorically different from those of free-living adults, which may restrict host seeking to iL3s. The human-parasitic threadwormStrongyloides stercoralisand hookwormAncylostoma ceylanicumhave highly dissimilar olfactory preferences, suggesting that these two species may use distinct strategies to target humans. CRISPR/Cas9-mediated mutagenesis of theS. stercoralis tax-4gene abolishes iL3 attraction to a host-emitted odorant and prevents activation. Our results suggest an important role for chemosensation in iL3 host seeking and infectivity and provide insight into the molecular mechanisms that underlie these processes.

scholarly journals A PCR-Based Molecular Detection of Strongyloides stercoralis in Human Stool Samples from Tabriz City, Iran

2017 ◽  
Vol 85 (2) ◽  
pp. 17 ◽  
Author(s):  
Reza Ghasemikhah ◽  
Mohammad Tabatabaiefar ◽  
Seyed Shariatzadeh ◽  
Abbas Shahbazi ◽  
Teymour Hazratian
Keyword(s):  
Molecular Detection ◽  
Strongyloides Stercoralis ◽  
Stool Samples ◽  
Human Stool ◽  
Tabriz City

Factors influencing development of free-living generations of Strongyloides stercoralis

Parasitology ◽  
1988 ◽  
Vol 97 (1) ◽  
pp. 129-138 ◽  
Author(s):  
K. Shiwaku ◽  
Y. Chigusa ◽  
T. Kadosaka ◽  
K. Kaneko
Keyword(s):  
High Temperature ◽  
Incubation Temperature ◽  
Strongyloides Stercoralis ◽  
Test Tube ◽  
Paper Test ◽  
Free Living ◽  
Factors Influencing ◽  
Prednisolone Treatment ◽  
Duration Of Infection ◽  
Incubation Temperatures

SUMMARYThe effects of duration of infection and of temperature and nourishment in cultures on development of free-living generations of Strongyloides stercoralis were studied quantitatively. Rhabditiform larvae, 228–353 μm long, were collected from infected dogs with or without prednisolone treatment using the Baermann apparatus. Cultures were carried out by the filter paper test-tube method under the following conditions: incubation temperature 15–40°C and faecal dilution 1:0–1:16. Rhabditiform larvae developed predominantly to free-living females at incubation temperatures of 15–30°C and low faecal dilutions, but filariform larvae appeared mainly under extreme conditions such as high temperature. Recovery rates of filariform larvae were inversely related to those of females. It was remarkable that high temperature, but not low faecal dilution, affected development of filariform larvae. Although the appearance of free-living males was constant in various environmental conditions, the present study indicated an increase in free-living males with the duration of infection. Thus, it seems that free-living males are already fixed as male in the egg stage, and potential female rhabditiform larvae differentiate into free-living females or filariform larvae depending on environmental factors. There is no marked difference in the development of rhabditiform larvae into filariform larvae in either the immunosuppressed dog or the intact dog.

scholarly journals Exposure to dexamethasone modifies transcriptomic responses of free-living stages of Strongyloides stercoralis

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0253701
Author(s):  
Rutchanee Rodpai ◽  
Oranuch Sanpool ◽  
Tongjit Thanchomnang ◽  
Pokkamol Laoraksawong ◽  
Lakkhana Sadaow ◽  
...  
Keyword(s):  
Developmental Process ◽  
Endocrine System ◽  
Strongyloides Stercoralis ◽  
Differentially Expressed ◽  
The Novel ◽  
Rna Seq ◽  
Free Living ◽  
Risk Of Mortality ◽  
Dependent Protein ◽  
Embryonic Morphogenesis

Hyperinfection and disseminated infection by the parasitic nematode Strongyloides stercoralis can be induced by iatrogenic administration of steroids and immunosuppression and lead to an elevated risk of mortality. Responses of free-living stages of S. stercoralis to the therapeutic corticosteroid dexamethasone (DXM) were investigated using RNA-seq transcriptomes of DXM-treated female and male worms. A total of 17,950 genes representing the transcriptome of these free-living adult stages were obtained, among which 199 and 263 were differentially expressed between DXM-treated females and DXM-treated males, respectively, compared with controls. According to Gene Ontology analysis, differentially expressed genes from DXM-treated females participate in developmental process, multicellular organismal process, cell differentiation, carbohydrate metabolic process and embryonic morphogenesis. Others are involved in signaling and signal transduction, including cAMP, cGMP-dependent protein kinase pathway, endocrine system, and thyroid hormone pathway, as based on Kyoto Encyclopedia of Genes and Genomes analysis. The novel findings warrant deeper investigation of the influence of DXM on growth and other pathways in this neglected tropical disease pathogen, particularly in a setting of autoimmune and/or allergic disease, which may require the clinical use of steroid-like hormones during latent or covert strongyloidiasis.

scholarly journals Skin-penetrating nematodes exhibit life-stage-specific interactions with host-associated and environmental bacteria

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Ivan N. Chavez ◽  
Taylor M. Brown ◽  
Adrien Assié ◽  
Astra S. Bryant ◽  
Buck S. Samuel ◽  
...  
Keyword(s):  
Life Cycle ◽  
Life Stage ◽  
Behavioral Responses ◽  
Strongyloides Stercoralis ◽  
Amplicon Sequencing ◽  
Ecological Niches ◽  
Free Living ◽  
Egg Hatching ◽  
Host Seeking ◽  
Environmental Bacteria

Abstract Background Skin-penetrating nematodes of the genus Strongyloides infect over 600 million people, posing a major global health burden. Their life cycle includes both a parasitic and free-living generation. During the parasitic generation, infective third-stage larvae (iL3s) actively engage in host seeking. During the free-living generation, the nematodes develop and reproduce on host feces. At different points during their life cycle, Strongyloides species encounter a wide variety of host-associated and environmental bacteria. However, the microbiome associated with Strongyloides species, and the behavioral and physiological interactions between Strongyloides species and bacteria, remain unclear. Results We first investigated the microbiome of the human parasite Strongyloides stercoralis using 16S-based amplicon sequencing. We found that S. stercoralis free-living adults have an associated microbiome consisting of specific fecal bacteria. We then investigated the behavioral responses of S. stercoralis and the closely related rat parasite Strongyloides ratti to an ecologically diverse panel of bacteria. We found that S. stercoralis and S. ratti showed similar responses to bacteria. The responses of both nematodes to bacteria varied dramatically across life stages: free-living adults were strongly attracted to most of the bacteria tested, while iL3s were attracted specifically to a narrow range of environmental bacteria. The behavioral responses to bacteria were dynamic, consisting of distinct short- and long-term behaviors. Finally, a comparison of the growth and reproduction of S. stercoralis free-living adults on different bacteria revealed that the bacterium Proteus mirabilis inhibits S. stercoralis egg hatching, and thereby greatly decreases parasite viability. Conclusions Skin-penetrating nematodes encounter bacteria from various ecological niches throughout their life cycle. Our results demonstrate that bacteria function as key chemosensory cues for directing parasite movement in a life-stage-specific manner. Some bacterial genera may form essential associations with the nematodes, while others are detrimental and serve as a potential source of novel nematicides.

scholarly journals A new method to detect Strongyloides stercoralis from human stool.

1988 ◽  
Vol 16 (1) ◽  
pp. 11-17 ◽  
Author(s):  
TAMIKI ARAKAKI ◽  
HIDEO HASEGAWA ◽  
RYUJI ASATO ◽  
TSUYOSHI IKESHIRO ◽  
FUKUNORI KINJO ◽  
...  
Keyword(s):  
Strongyloides Stercoralis ◽  
New Method ◽  
Human Stool

scholarly journals Liposome-based transfection enhances RNAi and CRISPR-mediated mutagenesis in non-model nematode systems

2018 ◽  
Author(s):  
Sally Adams ◽  
Prachi Pathak ◽  
Hongguang Shao ◽  
James B. Lok ◽  
Andre Pires-daSilva
Keyword(s):  
Nematode Species ◽  
Strongyloides Stercoralis ◽  
Free Living ◽  
Functional Studies ◽  
Human Parasite ◽  
Wide Range ◽  
Free Living Nematode ◽  
Animal Phyla ◽  
Genomic Studies ◽  
Dauer Larvae

AbstractNematodes belong to one of the most diverse animal phyla. However, functional genomic studies in nematodes, other than in a few species, have often been limited in their reliability and success. Here we report that by combining liposome-based technology with microinjection, we were able to establish a wide range of genomic techniques in the newly described nematode genus Auanema. The method also allowed heritable changes in dauer larvae of Auanema, despite the immaturity of the gonad at the time of the microinjection. As proof of concept for potential functional studies in other nematode species, we also induced RNAi in the free-living nematode Pristionchus pacificus and targeted the human parasite Strongyloides stercoralis.

Sign in / Sign up

Export Citation Format

Share Document