A study published on PLOS Neglected Tropical Diseases recently has found that a laboratory method that detects and measures worm DNA in stool samples in real-time could improve detection and treatment, helping more people stay healthy and free from these diseases. 

The method, technically called polymerase chain reaction (qPCR), is a more accurate way to detect intestinal worm infections compared to the traditional microscope-based technique called Kato-Katz, which is commonly used. 

The research, led by scientists from Tanzania and Switzerland, also tested a new deworming drug called emodepside and compared its effectiveness to another drug, albendazole, a widely used treatment.

Describing qPCR as a "valuable tool" and “game-changer,” the scientists underscore its important role in diagnosing Soil-Transmitted Helminths (STHs) due to its superior sensitivity. They emphasize its effectiveness in test-and-treat strategies for early detection and containment of infections, stating, “This tool is particularly effective in test-and-treat approaches for the early detection and containment of STH infections.” They also stress the need to standardize procedures to ensure more comparable and reliable results, ultimately enhancing diagnostic accuracy for patients.

What the study found
The study compared how well Kato-Katz and qPCR detected infections caused by Ascaris lumbricoides, Trichuris trichiura, and hookworms. The findings showed that qPCR was better at detecting infections, especially for A. lumbricoides. The results from qPCR and Kato-Katz did not always match, indicating that Kato-Katz may miss some infections.

When evaluating the effectiveness of treatments, qPCR showed lower cure rates for both emodepside and albendazole compared to Kato-Katz. However, qPCR also confirmed that emodepside was more effective than albendazole in treating T. trichiura and A. lumbricoides infections.

Understanding the science
Kato-Katz Method: This is a traditional technique used to detect worm eggs in stool samples under a microscope. It is inexpensive and widely used but may not always detect infections accurately.

qPCR (Real-time Polymerase Chain Reaction): This is a laboratory method that detects and measures worm DNA in stool samples. It is much more sensitive than Kato-Katz, meaning it can detect infections even when the number of worms is low.

Intestinal Worms (Soil-Transmitted Helminths): These include parasites like Ascaris lumbricoides (roundworm), Trichuris trichiura (whipworm), and hookworms. They spread through contaminated soil and can cause serious health problems if left untreated.

Deworming Drugs: Medications like albendazole and emodepside are used to kill these worms and clear infections. Albendazole is the standard treatment, while emodepside is a newer drug being tested for effectiveness.

Why these findings matter?
Intestinal worms affect more than 1.5 billion people worldwide, causing problems like stomach pain, anemia, poor nutrition, and stunted growth in children. This study highlights that Kato-Katz, the method recommended by the World Health Organization (WHO), is not always accurate. More reliable tests like qPCR could help improve diagnosis and make sure treatments are working effectively.

Ifakara scientist co-led the study
This study was a collaborative effort co-led by Christian Lotz from Swiss TPH and Emmanuel Mrimi from Ifakara Health Institute. Other contributors involved in the study include Pierre Schneeberger, Jan Hattendorf, and Jennifer Keiser also from Swiss TPH and Salim Ali from Public Health Laboratory-Ivo de Carneri in Tanzania.

Read the full publication here.