A Scalable Strategy for Interrupting Tuberculosis Transmission through Environmental Air Sampling

Sunil Raina¹, Matthias Schneider², Stephane Bilodeau³, Yaneer Bar-Yam⁴

¹ Dr. RP Government Medical College, Tanda (HP), India and World Health Network
² Medical and Biological Physics, TU Dortmund University and World Health Network
³ Department of Bioengineering, McGill University and World Health Network
⁴ New England Complex Systems Institute and World Health Network

Abstract

Tuberculosis (TB), particularly in its drug-resistant forms, remains a critical global health challenge. Despite expanded treatment programs, stigma, delayed detection, and gaps in implementation continue to hinder progress toward TB elimination. This paper proposes a scalable, community-based environmental surveillance strategy using low-cost air sampling in shared indoor spaces. By detecting airborne Mycobacterium tuberculosis (Mtb) DNA in high-risk environments, we enable early, stigma-free identification of transmission zones and create new entry points for public health action. This approach complements existing person and environmental testing (such as wastewater testing) diagnostics and offers a rapid, portable and localized intervention model for interrupting TB transmission in diverse settings. Initial deployment will take place in India and expand globally.

1. Introduction

Tuberculosis remains one of the world’s deadliest infectious diseases, with an estimated 10.6 million cases and 1.3 million deaths globally in 2022, including 450,000 drug-resistant TB (DR-TB) cases [1–3]. Drug-resistant TB, in particular, presents a growing biosecurity risk. While access to TB diagnosis and treatment has improved globally, key barriers remain. Surveillance systems do not always detect cases quickly. Social stigma [4-7] discourages some people from being tested. Many people avoid or postpone medical evaluation despite symptoms. Together, these factors allow transmission to continue undetected — especially in crowded indoor environments.

This paper introduces a complementary strategy for TB control: the use of environmental air sampling to detect airborne Mtb DNA in shared spaces such as homes, schools, public transport, and religious gathering sites. The goal is not to replace individual testing, but to identify sites of likely transmission, allowing communities and health systems to act earlier, faster, and without blame. This shifts the focus from who is sick to whether transmission is occurring here, enabling proactive interventions that avoid stigma.

2. Why Environmental Testing?

2.1 The Problem of Stigma

Traditional TB testing requires individuals to self-identify or present with symptoms, which can carry severe social penalties in many communities — including loss of employment, loss of marriage prospects, and housing discrimination. As a result, people delay testing or avoid it entirely. Even where free treatment and food support are available, the perceived cost of diagnosis remains high.

2.2 The Opportunity in Air

TB is primarily an airborne disease [8,9]. Individuals with active pulmonary TB emit aerosolized bacilli that can remain suspended in indoor air for extended periods, especially in poorly ventilated spaces. While person-based diagnostics focus on symptoms and direct detection, air sampling allows us to identify risk before individuals are diagnosed or present for care. It shifts the question from “who is sick” to “is transmission occurring here?”

Environmental detection focuses on identifying transmission zones, creating an avenue for action that does not rely on individual disclosure while offering a shared starting point for community response.

The detection of pathogens in the air is not new [10-13]. The same method can be applied to other airborne pathogens. Special equipment has been developed for air testing, but it is quite costly [14]. Recent studies have shown that the method is robust and off-the-shelf, and DIY construction can be used effectively to perform air testing using fans and filters [15]. 

3. The Proposed Model

3.1 Device

We use a low-cost, high-airflow air sampler constructed from locally available materials (See Fig. 1):

• 12V fan (or integrated rechargeable unit)
• Kitchen funnel
• PTFE membrane filter (0.3–0.45 μm pore size)

Air is drawn through the funnel through the filter for 1–8 hours in a shared indoor setting. The filter is then removed and sent for DNA-based detection (PCR or LAMP).

3.2 Deployment Sites

Priority spaces include:

• Prayer halls
• Schools
• Large households
• Public transportation (especially long-haul trains, buses, and airplanes)
• Clinics and pharmacies

Sampling occurs passively, without identifying individuals. Positive samples trigger outreach, follow-up testing, treatment, ventilation interventions, or focused awareness efforts.

3.3 Surface Swabbing as Complementary Detection

In addition to air sampling, surfaces in the same environment can be swabbed during the same deployment period. This technique, also supported by recent studies [6], can help identify pathogen deposition and extend the spatial sensitivity of environmental surveillance. Surface swabs can be collected from benches, windowsills, tables, and other exposed areas, and both samples are tested using the same downstream lab protocols (PCR or LAMP). Integrating surface swabbing into field sampling would enhance situational awareness without increasing infrastructure cost.

3.4 Cost and Feasibility

Each unit costs approximately ₹1,500 (~$18 USD), including rechargeable power. Filters are single-use (~₹200 each). The device is hand-carried, battery-powered, and requires only simple mechanical assembly. All components are locally available in India. The airflow of these units (~850–1400 L/min, based upon fan specification) is comparable to or exceeds that of specially developed commercial devices, including models costing 300× more. 

4. Pilot Sites and Initial Implementation

This initiative will begin in India, where national programs already support strong TB surveillance and where drug-resistant TB remains a priority challenge. India accounts for ~28% of global TB cases and benefits from an established national TB program, a broad laboratory network, and an extensive community health worker infrastructure. Project partners include public health leaders, physicians, and community organizers.

Initial pilot sites will include locations of extended occupancy, including prayer spaces (high occupancy) and schools (protection of children). We are finalizing device validation, testing lab protocols, and deployment workflows. Sampling will begin in these settings, coordinated with community health workers and local clinics, and will include training health workers, validating capture efficiency, and establishing data-to-action protocols.

5. Impact Potential

Environmental testing complements existing strategies by:

• Bypassing stigma and enabling proactive detection
• Identifying hotspots for airborne transmission
• Supporting community-level prevention measures
• Providing visible, actionable feedback for system response

The approach may also generalize to other airborne pathogens (e.g. COVID-19, influenza), expanding its utility as a tool for global respiratory disease control, including current and future zoonotic outbreaks.

6. Next Steps and Collaboration Invitation

We are seeking partners in:

• Lab testing and diagnostic analysis
• Field deployment and logistics
• Community engagement
• Global coordination and scaling

This project is an opportunity to demonstrate how targeted, systems-aware implementation can unlock progress where conventional approaches stall. This project is not only an intervention — it is a test case for how rapid, systems-based solutions can be scaled globally. We invite collaborators from science, policy, design, public health, and civil society to join us. 

Acknowledgement: This paper was developed through the Unpolitics working group network.

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