Helmintex assay detects low intensity schistosomiasis infections

March 8, 2018, Public Library of Science
Dusk in Candeal, Sergipe, northeastern Brazil. Credit: Graeff-Teixeira, et al, 2018

Individuals who release low numbers of schistosome eggs in their feces may not be detected by classical methods to detect schistosomiasis. Instead, the Helmintex method— which uses a magnetic field to isolate eggs—is more sensitive for these low intensity schistosomiasis infections, researchers report in PLOS Neglected Tropical Diseases.

Schistosomiasis is a common infection that affects over 290 million individuals, especially in Sub-Saharan Africa, Asia and South America. Classical diagnostic methods, including the Kato-Katz (KK) fecal smear recommended by the World Health Organziation, are not accurace in situations where low egg burden is present in stool. Alternative methods, including a point-of-care immunodiagnostic for schistosome cathodic circulating antigen in urine (POC-CCA) and the Helmintex (HTX) , have been proposed as substitutes.

In the new work, Carlos Graeff-Teixeira of the Pontificia Universidade Catolica de Rio Grande de Sul, and colleagues compared the KK, POC-CCA and HTX methods in a population-based study. 461 children and adults from Candeal, Brazil provided stool, urine, and blood samples for the comparison; an additional 220 submitted at least one specimen type.

The prevalence of schistosomiasis was found to be 71% with the POC-CCA method, 40% with HTX, and 11% with KK. More than 70% of individuals had very low egg burdens in their feces. However, the POC-CCA method provided the lowest proportion of true positive results. The HTX method was 100% sensitive with egg burdens higher than 1.3 epg and detected in 29% of the samples that were negative according to the KK method.

"The HTX method is very sensitive and should be used as a reference method for diagnosing intestinal schistosomiasis and for comparative evaluation of other tests," the researchers say. "The HTX method should also be considered for use in the monitoring and certification of transmission interruption."

Explore further: Alternative methods needed to detect all schistosomiasis cases

More information: Catieli Gobetti Lindholz et al, Study of diagnostic accuracy of Helmintex, Kato-Katz, and POC-CCA methods for diagnosing intestinal schistosomiasis in Candeal, a low intensity transmission area in northeastern Brazil, PLOS Neglected Tropical Diseases (2018). DOI: 10.1371/journal.pntd.0006274

Related Stories

Alternative methods needed to detect all schistosomiasis cases

February 22, 2018
To detect detect intestinal schistosome infections, the World Health Organization recommends using the Kato-Katz technique, which analyzes slides of fecal matter. But the approach often misses people who are infected with ...

Researcher develops vaccine for fatal disease

October 20, 2015
Over 200 million people in 74 countries suffer from schistosomiasis and four times that many are at risk for the disease since they do not have access to clean water. A recent discovery in the Texas Tech University Health ...

Effectiveness of point of care diagnostics for schistosomiasis

March 11, 2015
Researchers from the Cochrane Infectious Disease Group, hosted at LSTM, have conducted an independent review to assess how well point of care tests detect Schistosoma infections in people living in endemic regions.

Infection with two species of schistosome does not affect treatment efficacy

October 15, 2015
The parasitic disease schistosomiasis is caused by a trematode flatworm, different species of which can affect either the intestine or the urinary tract. Mixed species (co-) infections are common, and research is needed to ...

Three Gorges Dam alters downstream schistosomiasis rates

July 6, 2017
The Three Gorges Dam is a massive hydroelectric dam that spans the Yangtze River in central China and became fully operational in 2010. Ecological changes caused by the dam have altered the distribution of snails—including ...

New process may lead to vaccine for schistosomiasis

June 12, 2017
Cornell and Ludwig Institute for Cancer Research scientists have developed a way to produce a protein antigen that may be useful as vaccine for schistosomiasis – a parasitic disease that infects millions of people, mostly ...

Recommended for you

Scientists make significant discovery in the fight against drug-resistant tuberculosis

September 20, 2018
A team of scientists have identified a naturally occurring antibiotic that may help in the fight against drug-resistant Tuberculosis.

Anti-cancer drugs may hold key to overcoming antimalarial drug resistance

September 20, 2018
Scientists have found a way to boost the efficacy of the world's most powerful antimalarial drug with the help of chemotherapy medicines, according to new research published in the journal Nature Communications.

Affordable Care Act: Study finds surprising gaps in HIV care providers' knowledge

September 20, 2018
A new study has revealed surprising gaps in some HIV medical providers' knowledge of the Affordable Care Act, with more than a quarter of providers surveyed unable to say whether their state had expanded Medicaid.

Preventing a dengue outbreak at the 2020 Summer Olympics

September 20, 2018
In 2014, a dengue outbreak unexpectedly occurred in Tokyo. What does that mean for the 2020 summer Olympics and Paralympics being held in the city? Researchers report this week in PLOS Neglected Tropical Diseases that new ...

Researchers discover influenza virus doesn't replicate equally in all cells

September 19, 2018
The seasonal flu is caused by different subtypes of Influenza A virus and typically leads to the death of half a million people each year. In order to better understand this virus and how it spreads, University of Minnesota ...

Flu season forecasts could be more accurate with access to health care companies' data

September 19, 2018
In an era when for-profit companies collect a wealth of data about us, new research from The University of Texas at Austin shows that data collected by health care companies could—if made available to researchers and public ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.