Tuberculosis: The Persistent Global Threat and Its Complex Interactions with Human Health

M. bovis infection in humans causes similar disease manifestations but is more often associated with non-pulmonary lesions, as transmission typically occurs through consumption of contaminated dairy products (6). Farm workers exposed to infected cattle are at risk of pulmonary infections due to airborne exposure.

TB remains a major global health concern. In 2008, the World Health Organization (WHO) estimated 8.9–9.9 million incident TB cases and 9.6–13.3 million prevalent cases worldwide (6). The highest burden was reported in Asia (55% of cases) and Africa (30%), while cases in North America remained low due to effective prevention and treatment programs. In Canada, 1,600 new and re-treatment TB cases were reported in 2008, with 1.1% classified as multidrug-resistant TB (MDR-TB) and 0.07% as extensively drug-resistant TB (XDR-TB) (6). Tuberculosis (TB) remains a significant public health concern in both the United States and Canada. Recent outbreaks have underscored the need for vigilant monitoring, rapid detection, and effective treatment strategies.

In early 2024, Kansas City, Kansas, experienced a notable TB outbreak. By January 24, 2025, health officials reported 67 active TB cases and 79 latent infections. This outbreak resulted in two fatalities and is considered one of the largest in recent U.S. history. The Centers for Disease Control and Prevention (CDC) has been collaborating with local health departments to manage and contain the spread.(7)

While Canada maintains a relatively low overall TB incidence compared to global figures, localized outbreaks in urban centers and Indigenous communities—driven by factors such as overcrowded housing, socio-economic challenges, and limited healthcare access—have prompted rapid public health responses, including enhanced screening and culturally tailored interventions. These outbreaks underscore the importance of ongoing surveillance and targeted strategies to further reduce TB incidence in Canada (Public Health Agency of Canada, 2023).

Nationally, TB cases have seen a resurgence. In 2023, the United States reported approximately 9,600 TB cases, reflecting an increase from previous years. This upward trend highlights the ongoing challenges in TB prevention and control. (8)

In Canada, TB surveillance data from 2012 to 2021 indicates fluctuating incidence rates. While the overall number of cases has remained relatively stable, certain regions and populations continue to experience higher rates of TB. The Public Health Agency of Canada emphasizes the importance of targeted interventions to address these disparities and aims to reduce the national TB incidence to less than or equal to one case per 100,000 population by 2035. (9)

Rapid and accurate detection of TB is crucial for effective treatment and prevention of transmission. Traditional diagnostic methods, such as sputum smear microscopy and culture, have been complemented by molecular techniques like polymerase chain reaction (PCR) assays. These molecular methods offer quicker results and improved sensitivity. (10)

Innovations in diagnostic technology have further enhanced TB detection capabilities. The integration of artificial intelligence (AI) and machine learning algorithms with chest radiography has shown promise in improving diagnostic accuracy. Studies have demonstrated that AI-based systems can assist in the early detection of TB, particularly in resource-limited settings. (11)

HIV co-infection significantly increases the risk of TB progression, with an estimated 1.1–1.7 million deaths occurring among HIV-negative individuals and 0.45–0.62 million deaths among HIV-positive individuals globally in 2008 (6). MDR-TB and XDR-TB cases continue to rise, complicating treatment efforts, particularly in India and China, where the highest number of resistant cases have been reported (6).

TB is primarily transmitted through airborne droplets generated by coughing, sneezing, or speaking. The infectious dose is extremely low, with an estimated ID50 of fewer than 10 bacilli (1). Nosocomial transmission poses a significant risk, particularly for healthcare workers. Additionally, exposure to infected animals, contaminated dairy products, and autopsy materials can lead to infection (12).

By place of birth, 79% of TB cases in 2023 were born outside of Canada and 21% were born in Canada. Of TB cases born in Canada, 37% were First Nations, 37% were Inuit, 24% were non-Indigenous and 3% were Métis.TB largely impacts Inuit, First Nations, and persons born outside of Canada.(13) In 2023, there were 2,217 cases of TB reported in Canada. This corresponds to a rate of occurrence of new TB cases (incidence) of 5.5 cases per 100,000 population. (13)

Risk factors for TB progression include HIV infection, malnutrition, diabetes, tobacco use, and immunosuppressive therapies. Organ transplant recipients are particularly vulnerable, making latent TB screening essential before transplantation (3).

TB diagnosis involves chest X-rays, direct smear microscopy, bacterial culture, and nucleic acid amplification techniques such as PCR (1). The Mantoux tuberculin skin test and gamma interferon release assays are used for detecting latent infection (1).

First-line treatment consists of a six-month regimen of isoniazid, rifampin, ethambutol, and pyrazinamide (6). MDR-TB is resistant to at least isoniazid and rifampin, requiring alternative drugs such as fluoroquinolones and second-line injectable agents like amikacin and capreomycin (6). M. bovis is naturally resistant to pyrazinamide and is treated with isoniazid and rifampin for nine months (1).

Drug-resistant TB strains present a major challenge to disease control. MDR-TB and XDR-TB require longer and more complex treatment regimens with increased toxicity and cost (6). Prevention efforts focus on early detection, effective treatment, and vaccination. The Bacille Calmette-Guérin (BCG) vaccine, derived from an attenuated M. bovis strain, offers protection against severe TB forms, particularly in children (1). Research is ongoing to develop more effective vaccines and immunotherapies (6).

1. tuberculosis can survive for months on dry surfaces and remains viable in environmental reservoirs such as soil, wood, and sputum (1). The bacteria are resistant to many disinfectants but are susceptible to sodium hypochlorite, hydrogen peroxide, and glutaraldehyde (1). Heat treatment at 121°C for at least 15 minutes is effective in inactivating mycobacteria (1).

CREM Co Labs is at the forefront of developing advanced diagnostic solutions for infectious diseases, including TB. Utilizing cutting-edge molecular technique. CREM Co Labs offers rapid and reliable antimicrobial effectiveness assays for Drug-resistant TB strains and TB detection services. Their innovative approach aims to enhance early diagnosis, facilitate timely treatment, and ultimately contribute to global TB control efforts.

In conclusion, TB remains a leading cause of morbidity and mortality worldwide. Despite significant progress in diagnosis and treatment, drug resistance, co-infections, and transmission challenges continue to pose major public health threats. Strengthening global efforts in surveillance, vaccination, and innovative treatment strategies is essential to control TB and mitigate its impact on human health,  the recent TB outbreaks in the United States and the ongoing challenges in Canada underscore the critical need for continued vigilance, advanced diagnostics, and effective public health interventions. Organizations like CREM Co Labs play a pivotal role in advancing antimicrobial effectiveness assays for Drug-resistant TB strains and TB detection and supporting efforts to curb the spread of this enduring infectious disease. In 2023, TB drug resistance was low and consistent with trends observed in the past decade in Canada.

The Public Health Agency of Canada is collaborating with Federal, Provincial, Territorial, and Indigenous partners to develop an approach for TB elimination in Canada.(13)

Together, we can end TB.

References

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2. https://www.who.int/health-topics/tuberculosis#tab=tab_1
3. Rahimifard N, Mahmoudi S, Mamishi S, Pourakbari B, Prevalence of latent tuberculosis infection in transplant candidates: A systematic review and meta-analysis, Microbial Pathogenesis, Volume 125, 2018, Pages 401-410, ISSN 0882-4010, https://www.sciencedirect.com/science/article/abs/pii/S0882401018301104
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5. https://www.canada.ca/en/public-health/services/diseases/tuberculosis.html
6. Canadian Tuberculosis Standards 8th Edition, 2022. https://www.linksmedicus.com/news/canadian-tuberculosis-standards-8th-edition/
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8. https://www.cdc.gov/tb-surveillance-report-2023/summary/national.html?utm_source=chatgpt.com
9. https://www.canada.ca/en/public-health/services/publications/diseases-conditions/tuberculosis-canada-expanded-report-2012-2021.html?utm_source=chatgpt.com
10. https://www.cdc.gov/tb/hcp/testing-diagnosis/clinical-and-laboratory-diagnosis.html?utm_source=chatgpt.com
11. Hansun S, Argha A, Liaw ST, Celler BG, Marks GB. Machine and Deep Learning for Tuberculosis Detection on Chest X-Rays: Systematic Literature Review. J Med Internet Res. 2023 Jul 3;25:e43154. doi: 10.2196/43154. PMID: 37399055; PMCID: PMC10365622.
12. https://www.canada.ca/en/public-health/services/diseases/tuberculosis.html
13. https://www.canada.ca/en/public-health/services/publications/diseases-conditions/tuberculosis-disease-2023-infographic.html