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Review
. 2015;2(4):189-200.
doi: 10.1007/s40475-015-0064-9. Epub 2015 Oct 3.

Human Ascariasis: Diagnostics Update

Affiliations
Review

Human Ascariasis: Diagnostics Update

Poppy H L Lamberton et al. Curr Trop Med Rep. 2015.

Abstract

Soil-transmitted helminths (STHs) infect over one billion people worldwide. Ascariasis may mimic a number of conditions, and individual clinical diagnosis often requires a thorough work-up. Kato-Katz thick smears are the standard detection method for Ascaris and, despite low sensitivity, are often used for mapping and monitoring and evaluation of national control programmes. Although increased sampling (number of stools) and diagnostic (number of examinations per stool) efforts can improve sensitivity, Kato-Katz is less sensitive than other microscopy methods such as FLOTAC®. Antibody-based diagnostics may be a sensitive diagnostic tool; however, their usefulness is limited to assessing transmission in areas aiming for elimination. Molecular diagnostics are highly sensitive and specific, but high costs limit their use to individual diagnosis, drug - efficacy studies and identification of Ascaris suum. Increased investments in research on Ascaris and other STHs are urgently required for the development of diagnostic assays to support efforts to reduce human suffering caused by these infections.

Keywords: Ascariasis; Ascaris; Diagnosis; Immunology; Microscopy; PCR.

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Figures

Fig. 1
Fig. 1
A. lumbricoides life cycle and diagnostic markers of infection. After being swallowed, an A. lumbricoides larva hatches from the infective egg*, migrates into the vascular system and is transported through the portal veins and right side of the heart to the pulmonary circulation. Unable to cross the capillary network, the parasite penetrates the walls of the alveoli, migrates to the larynx and is swallowed, ending up as an adult worm in the small intestines. The female parasite lays tens of thousands of eggs daily that, through stool excretion, enter the environment and may infect other human hosts. The time from egg ingestion to larval migration takes 10 to 14 days, with egg production starting from 2 to 3 months. Adult worms can live in humans for 1–2 years [5]. *Only fertilised eggs may become infective

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