RESUMEN
The skin-penetrating gastrointestinal parasitic nematode Strongyloides stercoralis causes strongyloidiasis, which is a neglected tropical disease that is associated with severe chronic illness and fatalities. Unlike other human-infective nematodes, S. stercoralis cycles through a single free-living generation and thus serves as a genetically tractable model organism for understanding the mechanisms that enable parasitism. Techniques such as CRISPR/Cas9-mediated mutagenesis and transgenesis are now routinely performed in S. stercoralis by introducing exogenous DNA into free-living adults and then screening their F1 progeny for transgenic or mutant larvae. However, transgenesis in S. stercoralis has been severely hindered by the inability to establish stable transgenic lines that can be propagated for multiple generations through a host; to date, studies of transgenic S. stercoralis have been limited to heterogeneous populations of transgenic F1 larvae. Here, we develop an efficient pipeline for the generation of stable transgenic lines in S. stercoralis. We also show that this approach can be used to efficiently generate stable transgenic lines in the rat-infective nematode Strongyloides ratti. The ability to generate stable transgenic lines circumvents the limitations of working with heterogeneous F1 populations, such as variable transgene expression and the inability to generate transgenics of all life stages. Our transgenesis approach will enable novel lines of inquiry into parasite biology, such as transgene-based comparisons between free-living and parasitic generations.
Asunto(s)
Animales Modificados Genéticamente , Strongyloides stercoralis , Strongyloides stercoralis/genética , Animales , Humanos , Sistemas CRISPR-Cas , Estrongiloidiasis/parasitología , Estrongiloidiasis/genética , Transgenes , Ratas , LarvaRESUMEN
Anaemia is an important cause of morbidity and mortality globally. Among infectious agents responsible for anaemia, helminthic infections are often neglected, particularly in non-endemic countries. However, they should not be neglected in this setting, as international travel and migration are on the rise. In this narrative review, we aimed to describe soil-transmitted helminths as a cause of or contributing factor to anaemia, focusing on hookworms (Necator americanus and Ancylostoma duodenale), the whipworm (Trichuris trichiura), the roundworm (Ascaris lumbricoides), and the threadworm (Strongyloides stercoralis). A general review on the epidemiology, lifecycle, and clinical spectrum of anaemia is proposed, with a special focus on helminthic infections' association with anaemia as well as the diagnostic approach, which are both particularly important in non-endemic settings.
RESUMEN
A case of Strongyloides stercoralis hyperinfection in a patient with dermatomyositis and diabetes mellitus is herein reported. The case was a 60-year-old female admitted due to watery diarrhea and unconsciousness. She had a 10-year history of chronic immunosuppressive therapy including methotrexate and prednisolone for dermatomyositis. Stool parasitological examination revealed numerous rhabditiform larvae of threadworm "S. stercoralis." Larva in stool sample was characterized by sequencing of mitochondrial DNA. After treatment with ivermectin, the patient recovered without evidence of S. stercoralis in follow-up stool samples. In endemic areas, stool examination for detection of S. stercoralis should be performed on a regular basis for all patients receiving immunosuppressive therapy, as early detection and treatment are necessary to minimize complications of severe strongyloidiasis.