TB vaccination programs and deworming need to go together, say scientists

There is an immediate need to combine deworming and TB vaccination programs, according to a report by researchers from India and USA that appeared in a recent issue of the journal PLOS Neglected Tropical Diseases. They studied latent TB patients who are infected with the disease-causing bacterium but cannot spread it to others because the infection is kept under control by the immune system of the body. Some of these latent TB patients were also infected with the threadworm Strongyloides stercoralis. This worm survives in the small intestine of many organisms including humans, cats, dogs, and non-human primates like chimps. It spreads through feces contaminated soil common in rural areas from developing countries where sanitation standards are poor.  

They studied a total of 132 individuals in Tamil Nadu, with 44 people in each of the three groups- those with latent TB, threadworm infestation, and with latent TB and worm infection both. They found that latent TB patients with worm infestation had lower numbers of immune cells called B-cells that secrete antibodies that keep TB under check. In addition to lowered B-cell numbers, they had reduced levels of antibodies against TB in their blood that signifies a weak immune response against TB in their body. When these patients were treated with deworming drugs ivermectin or albendazole, the immune cells and antibody levels recovered.

“The implications of our study are twofold: threadworms might promote reactivation of active TB in latent TB infected patients, and also negatively influence the immune response to TB vaccines. We suggest that treatment for worm infection would make for a prudent first step in the conduct of TB vaccine trials in countries endemic for both TB and worms”, says Professor Subash Babu, Scientific Director at the National Institute of Research in Tuberculosis, formerly Tuberculosis Research Center in Chennai.

The research team comprised of Rajamanickam Anuradha, Saravanan Munisankar, Yukti Bhootra, Chandrakumar Dolla, Paul Kumaran, Thomas B Nutman, and Subash Babu. The study was done at the National Institute for Research in Tuberculosis in Chennai and National Institutes of Health, Bethesda in USA. 

This news was published by Newsroom24X7, BioVoice, and India Science Wire. 

Reference: PLOS Neglected Tropical Diseases 11 (5): e0005569.