While some scientists in the country are working day and night to come up with child-friendly diagnostic test for Tuberculosis (TB), a recent study shows that trained rats increase the detection of the disease in children significantly and could help address the childhood TB diagnosis challenges.
The study conducted by the Sokoine University of Agriculture- Apopo TB Tanzania, indicated that when trained rats were given children’s sputum samples to sniff, they were able to pinpoint 68 per cent more cases of TB infections than detected through standard smear tests.
SUA -Apopo TB Tanzania Programme Manager, Dr Georgies Mgode told that TB diagnosis in children is a challenge with up to 94 per cent of children with the disease treated empirically in TB high-burden countries.
Dr Mgode said that the current TB detection methods are far from perfect, especially in under-resourced countries in Sub-Saharan Africa and South East Asia where the disease is prevalent, and where a reasonably cheap smear test is commonly used.
“Problems with this type of test are that the accuracy varies depending on the quality of sputum sample used, and very young children are often unable to provide enough sputum to be analysed,” he said.He added, “As a result, many children with TB are not bacteriologically confirmed or even diagnosed, which then has major implications for their possible successful treatment hence need for new diagnostic tests to better detect TB in children, especially in low and middle-income countries.
Dr Mgode further said TB is a deadly disease, which killed 1.3 million people worldwide in 2016, of which 130,000 were children. Sub Saharan Africa and South East Asia are among the regions with the highest burden of TB.He noted that a large proportion of TB patients remain undetected in most high-burden areas due to the poor sensitivity of smear microscopywidely used in these areas.
In many low-income countries, the diagnosis of pediatric TB is solely based on clinical evidence and smear microscopy. He said the sensitivity of adult sputum culture is 80 per cent but for children it is challenging to produce a sufficient volume of good-quality sputum needed for smear microscopy.
In northern Tanzania, it was found that pediatric TB contributed to 13 per cent of the total TB burden and 75 per cent of these had pulmonary TB, of which only 5.8 per cent of all TB patients were bacteriologically confirmed.
Nearly all of the children with TB were thus treated empirically. Trained TB detection rats have been in use in Tanzania and Mozambique as an enhanced case-finding tool under research, after smear microscopy, whereby they have increased TB case detection by over 40 per cent.
The TB detection facilities use African giant pouched rats, nicknamed ‘HeroRATs’, to detect the disease, the technology developed by a Belgian organisation – Apopo. Dr Mgode noted that if the rats detect positive cases, the results will further be confirmed using a World Health Organisation (WHO) endorsed concentrated microscopy techniques before the patients start treatment.
The objectives of the study were to determine the ability of trained rats to detect pediatric TB, and whether rats could enhance the detection of pediatric TB over standard of care.
The study was conducted in three regions in the country namely Dar es Salaam, Coast and Morogoro, from January 2011 to June 2015. Over 90 per cent of the participants were from Dar es Salaam city with a population of nearly 5 million people.
