Complex, stressful and painful are some the words coming from clinicians struggling to collect respiratory samples from children undergoing tuberculosis tests.
However, a new study shows stools offer a simple way to free children from sputum test that exposes them to the agonies of being hospitalised overnight and having a tube inserted through their noses.
KNCV Tuberculosis Foundation announced the stool-based diagnosis on Thursday at the 49th Union World Conference on Lung Health underway in the Hague, Netherlands.
Stool test the foundation’s researchers conducted in collaboration with the national TB control programmes of Ethiopia and Indonesia detected TB in all children who also had positive respiratory samples.
The absence of false negative stool samples makes the new method a potential global life-saver by ensuring millions of children at risk of TB and multidrug-resistant TB (MDR-TB) are tested, says its executive director Kitty van Weezenbeek.
“If further testing confirms the preliminary findings in Indonesia and Ethiopia, the potential of this method is enormous,” she said. “Being able to diagnose TB and MDR-TB from stool would mean that we have a method in our hands that can diagnose TB at the lowest healthcare level and can bring testing to hundreds of thousands of people. In that way, children can now get a microbiologically confirmed TB diagnosis at primary health centres, where that is currently not possible.”
According to The Union executive director José Luis Castro, easing the identification of thousands of children with TB and multidrug-resistant TB (MDR-TB) disease would drastically reduce the numbers of children under five dying from TB.
Currently, an estimated 239 000 children die every year from TB.
Children with TB rarely die when they receive standard treatment for the disease, but 90 percent of children who die from TB worldwide went untreated.
“No child should die from TB,” said Castro. “There is an urgent need to drastically step up investment in research and development that can deliver new and better diagnostic tools such as this stool test. Promising breakthroughs of this kind are needed if we are to make inroads into preventing illness and death from both active and MDR-TB.”
According to the National TB Control Programme in Lilongwe, nearly 17 000 people in Malawi have TB. Globally, World Health Organisation estimates that the curable disease kills 5 000 people every day .
However, diagnosis of the deadly infectious disease in Malawi mostly relies on screening sputum under a microscopes, which sometimes detects just 30 percent of infections.
Since 2015, Dignitas International, a public health think-tank based in Zomba, rolled out clinical trials of rapid urine-based testing done on the bedside. The bedside trial, which ended in October 2017, yields results within 30 minutes.
National TB Control Programme director James Mpunga said the study in Zomba will help the Ministry of Health (MoH) in understanding the contribution of newer diagnostic tests in identifying TB among HIV-positive patients.
“The yield of the conventional methods in picking TB among HIV positive patients is low and hence more sensitive methods are always welcome. Evidence on the effectiveness of Lam being a newer test is sought in order to help inform policy,” he told The Nation last year.
The emerging evidence about stool-based testing points to simple TB detection among children below five who cannot spit up in traditional methods used to get a sputum sample off them
It has been widely considered that stool is a difficult sample because it contains so many other bacteria and debris which encapsulates tuberculosis bacilli, the germs which cause TB. According to scientists, this makes it difficult to “free” the bacilli without multiple cleaning steps that require sophisticated equipment.
But the KNCV study in Ethiopia involves mixing a sample of stool with a sample of sample reagent buffer which comes with every Xpert machine cartridge in bottles of 8 millilitres.
There were no false negative stool samples, according to the researchers.
The stool test also identifies resistance to rifampicin, a symptom of for MDR-TB.
Currently, obtaining sputum test, children are referred to specialised service providers, as testing is not possible at the community level.
Additionally, current stool processing methods use sophisticated centrifugation and filtration that are only available in referral laboratories, usually attached to referral hospitals.