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environmental assay data sheet
Ascaris lumbricoides PCR test
Ascaris lumbricoides PCR test
Test
code: X0052 -
Ultrasensitive qualitative detection of Ascaris lumbricoides by
real time PCR
Ascaris lumbricoides is a parasitic
roundworm (nematode) that infects humans exclusively, causing
ascariasis. It is the most common human helminthic infection
worldwide, especially in tropical and subtropical regions with
poor sanitation.
The adult worms are big, with females typically measuring 20-35 cm in
length, while males are 15-30 cm. They are usually pink or white
with tapered ends. The parasite is transmitted via the
fecal-oral route. Adult worms live in the lumen of the human
small intestine. Female worms can produce up to 200,000 eggs per
day. These eggs are excreted in the feces. Unfertilized eggs are
not infective, but fertilized eggs embryonate in the soil under
optimal conditions, such as moist, warm, and shaded areas. The
eggs become infective after 18 days to several weeks. When
infectious eggs are ingested from contaminated soil, food, or
water, these eggs hatch into larvae in the small intestine. The
larvae migrate through the bloodstream to the lungs and then
return to the intestines to mature into adults.
Many people infected with this parasite are asymptomatic. However, in
some heavy infestation cases, malnutrition, abdominal pain,
diarrhea, or more serious complications like intestinal
obstruction can occur. Treatment typically involves
antiparasitic medications like albendazole or mebendazole.
Prevention of infection relies on improved hygiene and
sanitation.
Diagnosis of the infection is mainly through microscopic examination of
the eggs in the stool. The parasite eggs are easy to recognize
due to their characteristic appearance: thick-shelled, oval, and
often mammillated (bumpy outer layer). However, polymerase chain
reaction is increasingly used in detecting
Ascaris lumbricoides,
especially in research, surveillance, and low-prevalence
settings where microscopy may lack sensitivity (Mejia et al.,
2013; Pecson et al., 2006).
Utilities:
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Check for
Ascaris lumbricoides
in feces, water, soil, and other environmental
samples
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Selection of appropriate remediation regimens
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Check for post-remediation absence of this parasite
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Help confirm the presence of this parasite in
animals
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Help minimize human exposure to this parasite
References:
Mejia R, Vicuña Y, Broncano N, Sandoval C, Vaca M,
Chico M, Cooper PJ, Nutman TB. A novel, multi-parallel,
real-time polymerase chain reaction approach for eight
gastrointestinal parasites provides improved diagnostic
capabilities to resource-limited at-risk populations. Am J Trop
Med Hyg. 2013 Jun;88(6):1041-7.
Pecson BM, Barrios JA,
Johnson DR, Nelson KL. A real-time PCR method for quantifying
viable ascaris eggs using the first internally transcribed
spacer region of ribosomal DNA. Appl Environ Microbiol. 2006
Dec;72(12):7864-72).
Specimen requirements:
2 ml of feces, or 10 ml of
water, or used water filter media; or 10 ml of soil; or environmental swabs
or swipes.
Contact Zoologix if advice is needed to determine an appropriate specimen type for a specific diagnostic application. For specimen types not listed here, please contact Zoologix to confirm specimen acceptability and shipping instructions.
For all
specimen types, if there will be a delay in shipping, or during
very warm weather, refrigerate specimens until shipped and ship
with a cold pack unless more stringent shipping requirements are
specified. Frozen specimens should be shipped so as to remain
frozen in transit. See shipping
instructions for more information.
Turnaround time:
2 business days
Methodology:
Qualitative real time polymerase chain reaction
Normal range:
Nondetected
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