New zoonotic TB road map sets intentionally ambitious targets

Biological samples are collected from from wildlife and livestock in Champasak, Laos. Photo by: Montakan Tanchaisawat / USAID / CC BY-NC

GUADALAJARA, Mexico — A group of United Nations agencies, scientific groups, and advocacy organizations last week laid out the ambitious Roadmap for Zoonotic Tuberculosis that one of its authors describes as intentionally aiming too high.

Setting moonshot goals, experts told Devex, aims to catalyze much-needed energy and attention to combating zoonotic TB, which is carried by animals but infects humans through unpasteurized milk, raw or undercooked meat and direct contact with infected animals. It is airborne as well.

In 2016, some 147,000 people came down with the disease and 12,500 died, according to World Health Organization figures released at the Union World Conference on Lung Health last week. Zoonotic TB is caused by Mycobacterium bovis rather than Mycobacterium tuberculosis, the latter being what we commonly know as TB.

Efforts to combat zoonotic TB have lagged well behind those on human TB. Health practitioners have few diagnostic tools to differentiate Mycobacterium bovis from Mycobacterium tuberculosis, meaning the true prevalence of the disease is unknown. Zoonotic TB, which more frequently affects organs outside the lungs such as the lymph nodes, is also resistant to one of the first-line anti-TB drugs, presenting treatment challenges.

“While there has been progress in combating TB, efforts to address zoonotic TB is really lacking, even in the TB community,” said Monica Dias, information and technical officer at the WHO’s Global TB Program. “We hope the roadmap will drive action and investment.”

The road map’s goals fall under three themes: improving the scientific base, reducing transmission at the animal-human interface and strengthening inter-sectoral and collaborative approaches. It was published on Oct. 12 by the WHO, World Organization for Animal Health, or OIE, Food and Agriculture Organization and Union Against TB and Lung Disease.

Some of the 2020 goals of the Roadmap include improving the detection, recording and reporting of zoonotic and bovine TB to allow for more accurate estimations of the disease burden; improving national food safety standards; and building the capacity of national veterinary services to detect and control bovine TB in livestock and wildlife.

The 2025 targets are more ambitious and include new, rapid diagnostic tools for zoonotic TB to be rolled out to high-risk groups; the development of an anti-TB vaccine for people; new diagnostic assays for livestock; and an effective bovine TB vaccine for livestock.

“There’s very clear recognition that these are aspirational targets with significant challenges,” Dr. Matthew Stone, deputy director-general of the OIE, told Devex. “We know there will be significant ongoing efforts after the actual dates.”

High hopes

The road map follows a One Health approach, which “recognizes that the health of people is connected to the health of animals and the environment,” according to the U.S. Centers for Disease Control. It argues that the human burden of TB cannot be reduced—and thus global goals can’t be reached—without improving standards of food safety and controlling bovine TB in the animal reservoir.

Dr. Paula Fujiwara, scientific director of the Union who was involved with writing the road map, told Devex the goals are intentionally overly ambitious.

“If you aim too low, I’ve learnt that in the TB world that’s not what you do for advocacy. You don’t have to be that precise, so I’ve gone the other way,” she said.

That ambition aims to spur the development of new tools, without which it will be difficult to truly combat the disease.

“If we don’t have new tools, then forget it. And that’s not just for bovine TB. I’m talking about TB in general. We need new diagnostics, new regimens that work together and a vaccine. To me, if we don’t have these things, then forget it,” she added.

Public health education will be an enormous component of fighting transmission, experts said. In parts of sub-Saharan Africa, for example, drinking unpasteurized milk and eating uncooked meat is widespread. Livestock owners also need better awareness about the disease, said Stone.

“We have to understand better what it takes to change behaviour. We have to put conditions in place to allow better alternatives to become a first choice,” he said. “The biggest challenge is supporting the regulatory capacity of veterinarian services and supporting behavioural changes among the livestock owners.”

Simeon Cadmus, professor of veterinary medicine from the University of Ibadan in Nigeria, said that most people “are uneducated and uninformed about zoonotic TB in the region.” He noted the lack of screening mechanisms for contaminated meat, uncontrolled movement of livestock and other animals across borders, and minimal or weak veterinary services.

A bovine vaccine is another major goal for tackling prevalence, though this may be some ways out, said Dr. Simona Forcella, a veterinarian at the OEI.

“I can’t say it will be something tomorrow or in the near future. We hope the deadline will be met … but I can’t give you a timeline,” she said.

In the interim, she said that meat inspection was one of the frontline responses veterinarians can put in place to avoid having contaminated meat in the food supply.

Way forward

Despite the ambitious push, some TB experts told Devex the road map was insufficient in one key way: It is focused only on cattle, hence “missing a lot of animals that are potential reservoirs for TB,” said Lisa Jones-Engel, zoonotic TB expert and assistant professor of anthropology at the University of Washington.

While cattle are considered to be the main hosts of Mycobacterium bovis, the disease is prevalent in wildlife as diverse as pigs in Europe, marsupials in New Zealand and buffaloes in Africa.

“If you don’t even know what you’re looking for and in what animals, how can you develop a vaccine? We don’t even have a good assay to allow us to distinguish Mycobacterium bovis from Mycobacterium tuberculosis. We’re so far behind I can’t imagine how they can reach these goals,” Jones-Engel said.

The lagging scientific response is one reason that advocates are pushing harder for behavioral and policy changes. Cadmus, for example, is currently piloting a project in southwest Nigeria, which offers farmers free vaccinations, anti-malarials and blood pressure testing if their animals—and themselves—are screened for TB.

“We need to proactively look at the countries where the system is broken, where there are no vets and the sanitation is poor,” he said. “We need to go back to where it all begins: the farmers. How can we reach them?”

Another key benchmark will be the United Nations high-level meeting on TB, to be held for the first time in 2018. Experts believe it will be a unique opportunity to foster more vigor into combating the epidemic.

Dr. Stone said he hopes the high-level meeting will secure a stronger political commitment.

 “We’re working on getting these priorities within the road map clearly understood and garnering some high-level commitment from our members and our funding partners internationally in the hope this plan gets put into place,” he said.

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About the author

  • Sophie Cousins

    Sophie Cousins a Devex Contributor based in South Asia. She is a health journalist focused on women and girls. She was previously based between Lebanon and Iraq, focusing on refugee health and conflict. She writes for international medical journals, including The Lancet, and for international news websites such as the Guardian.