Strongyloides in gram stain of sputum and stool in details
Strongyloides in gram stain of sputum
A patient was in intensive care unit (ICU) with history of aplastic anemia. Clinician sent his various specimens i.e. urine R/E , urine culture and sensitivity, similarly sputum for Gram stain and culture -sensitivity. All theses reports from those specimens were normal except Gram stain, in which an abnormal finding i.e. larva of Strongyloides encountered. On this basis, we requested for stool sample. Heavy load of larvae of Strongyloides was observed under the microscope as shown below.
Introduction
Strongyloides stercoralisis a human pathogenic parasitic roundworm causing the disease strongyloidiasis.
The Strongyloides stercoralis nematode can parasitize humans. The adult parasitic stage lives in tunnels in the mucosa of the small intestine. The genus Strongyloides contains 53 species.
Geographic Distribution
This infection is associated with fecal contamination of soil or water. so, it is a very rare infection in developed economies than in developing S. stercoralis can be found in areas with tropical and subtropical climates.
Estimates of the number of people infected vary with one estimate putting the figure at 370 million worldwide.
Life Cycle of Strongyloides
It completes into two stages
a) Free living cycle
b) Parasitic cycle
Morphology of Strongyloides stercoralis
Male having size of about 0.9 mm whereas female larger i.e. from 2.0 to 2.5 mm. Males can be distinguished from females by two these structures:
- the spicules
- and gubernaculum.
- Strongyloides stercoralis in gram stain of sputum as shown above image.
Autoinfection
It is an unusual feature of S. stercoralis. Auto infection is the development of L1 into small infective larvae in the gut of the host. These auto infective larvae penetrate the wall of the lower ileum or colon or the skin of the perianal region, enter the circulation again, travel to the lungs, and then to the small intestine, thus repeating the cycle.
Symptoms of strongyloidiasis
Initially many people infected are asymptomatic. Anyway, Symptoms include
- dermatitis:
- swelling,
- itching,
- larva currens,
- and mild hemorrhage at the site where the skin has been penetrated.
- Spontaneous scratch-like lesions may be seen on the face or elsewhere.
Diagnosis of strongyloidiasis
Fecal wet preparation :
showing larvae (juvenile, rhabditiform or filariform)
Culturing fecal samples on agar plates:
Trekking of Strongyloides on agar plate
Serology:
serodiagnosis through ELISA and duodenal fumigation.
Treatment of strongyloidiasis
Choice of drugs are-
- Albendazole
- Thiabendazole
- Ivermectin
- Mebendazole
- Piperazine.
References
- Medical Parasitology by Abhay R. Satoskar, Gary L. Simon, Peter J. Hotez and Moriya Tsuji
- Atlas of Medical Helminthology and ptotozoology -4th edn -P.L. Chiodini, A.H. Moody, D.W. Manser
- Merkell and voge’s medical parasitology
9th edition. - Parasitology: 12th edition
By K. D. Chatterjee - District laboratory practice in Tropical countries –Part-I .
By Monica cheesbrough. - Isenberg clinical microbiology procedures Handbook
2nd edition. Vol. 2