Diagnosis of Strongyloides stercoralis by morphological characteristics combine with molecular biological methods

Abstract

Strongyloidiasis is one of the neglected tropical diseases caused by infection with the nematode Strongyloides genus and distributed worldwide. Strongyloidiasis can be fatal in immunosuppressed patients induced hyperinfection or disseminated strongyloidiasis. Unfortunately, until now, due to the unspecific clinical symptom in infected individuals and the low sensitivity diagnosis of strongyloidiasis, many patients were misdiagnosed every year. Furthermore, the larvae of the Strongyloides stercoralis (S. stercoralis) is similar to other nematodes such as hookworm, Trichostrongylus increased the difficulty of diagnosis. In this case, the patient is a 63-year-old male person, who had a nearly 30 years medical history of asthma and emphysema, and 4-5-year medical history of diabetes. The sputum examination found some parasite larvae, then we identify the larvae using clinical observation and morphological characteristics combine with examined cytochrome oxidase subunit 1 (COX1) and 18S rRNA genes by PCR, sequence analysis and finally classified by phylogenetic analysis, the larvae were diagnosed as S. stercoralis. Our results showed that diagnosis with strongyloidiasis by morphological characteristics combine with molecular biological methods can improve the sensitive of diagnosis and provide a final diagnosis for the disease in the clinics.

Descriptive Investigation of Strongyloidiasis Infection and Characterization of Strongyloides stercoralis Using Morphological and Molecular-Based Methods

“…Thus, there is an urgent requirement for molecular-based diagnostics for strongyloidiasis. Although molecular assays have been established and validated for the diagnosis of strongyloidiasis in other countries [ 3 , 29 ], no such published records are available for Sri Lanka. This is the first report of the successful application of a molecular-based diagnostic for intestinal helminthiases in Sri Lanka using a multiplex PCR, facilitating the detection of multiple infections within a single platform with probable greater sensitivity than the traditional methods.…”

“…Strongyloidiasis is a soil-transmitted helminthiasis (STH), caused by the nematode Strongyloides stercoralis and to a lesser extent by the zoonotic species Strongyloides fuelleborni and Strongyloides cf fuelleborni [ 1 – 3 ]. Considered as the most neglected of the neglected tropical diseases in the world [ 4 ], it is endemic in Southeast Asia, Latin America, sub-Saharan America, and parts of Southeast United States [ 5 ] affecting an estimated 30–100 million individuals worldwide [ 6 ].…”

“…stercoralis infection, the noninfective rhabditiform larvae that hatch from ovum may rapidly develop into the infective filariform larvae (L3) within the small intestine and cause autoinfection by penetration of either mucus membrane (internal autoinfection) or skin (external autoinfection) or may be excreted to the environment in the noninfective (rhabditiform) stage requiring a soil phase of development to cause new infections. The tropical weather (warm and humid) prevailing in the endemic regions favors the sustenance of parasitic and free-living stages in the soil [ 3 , 14 ]. Walking barefoot and engaging in soil-related work, poor personal hygiene, unsatisfactory sanitation, and insufficient supplies of drinking water are risk factors for infection.…”

Laboratory Findings on a Patient with Strongyloies Stercoralis Pulmonary Infection after Long Term Steroid Hormone and Immunosuppressive Treatment

“…Strongyloidiasis is usually neglected in diagnosis because the infection is asymptomatic. Until now, due to the unspecific clinical symptom in infected individuals and the low sensitivity in strongyloidiasis diagnosis, many patients were misdiagnosed every year [4]. Herein, we report a misdiagnosed case of Strongyloies stercoralis infected female patient who had been admitted to four different hospitals for treatment, 3 she eventually died upon Strongyloies stercoralis hyperinfection with pulmonary infection involved.…”

Molecular characterization of human isolates of Strongyloides stercoralis and Rhabditis spp. based on mitochondrial cytochrome c oxidase subunit 1 (cox1)

“…Despite the efficiency of this culture method, it raises a possibility for the growth of other nematodes including hookworms [7], Trichostrongylus and Rhabditis species [8]. The larva of S. stercoralis is similar to those of such nematodes, increasing the difficulty of diagnosis [9]; especially in infection with Rhabditis species that like S. stercoralis, parasites larvae have been reported releasing in human [10][11][12][13]. Therefore, it requires a well-trained microscopist to differentiate S. stercoralis from Rhabditis speciesduring parasitological examinations, particularly in endemic areas of…”