Tuberculosis has nearly been eradicated from the United States. The biggest barrier preventing its eradication is:

Tuberculosis has nearly been eradicated from the United States. The biggest barrier preventing its eradication is:

• A. Lack of an effective treatment
• B. The zoonotic nature of the diseases
• C. Wildlife reservoirs of the disease
• D. The extended incubation period for the disease

Answer: (C)

The biggest barrier is wildlife reservoirs. In the United States, tuberculosis persists in wildlife populations—most notably white-tailed deer and other free-ranging animals—which maintain and spread the infection even when domestic cattle and human cases are being actively controlled. This creates a continuous source of reinfection for livestock and a risk of spillover to people, making eradication far more complex and costly than strategies that focus only on humans and cattle. Because surveillance and control efforts can effectively reduce TB in cattle and humans, but cannot feasibly eliminate infection in widespread wildlife, the disease stubbornly remains in the environment. This is why wildlife reservoirs present the most significant hurdle to eradication. The other reasons don’t fit as the main barrier: there are effective treatments for TB in humans and cattle, so lack of treatment isn’t the central obstacle; while a long incubation period and latent infections complicate detection, they are manageable factors compared to the persistent wildlife source; and although TB is zoonotic, the core challenge for eradication in the US is the ongoing wildlife reservoir that sustains transmission across species.

The biggest barrier is wildlife reservoirs. In the United States, tuberculosis persists in wildlife populations—most notably white-tailed deer and other free-ranging animals—which maintain and spread the infection even when domestic cattle and human cases are being actively controlled. This creates a continuous source of reinfection for livestock and a risk of spillover to people, making eradication far more complex and costly than strategies that focus only on humans and cattle.

Because surveillance and control efforts can effectively reduce TB in cattle and humans, but cannot feasibly eliminate infection in widespread wildlife, the disease stubbornly remains in the environment. This is why wildlife reservoirs present the most significant hurdle to eradication.

The other reasons don’t fit as the main barrier: there are effective treatments for TB in humans and cattle, so lack of treatment isn’t the central obstacle; while a long incubation period and latent infections complicate detection, they are manageable factors compared to the persistent wildlife source; and although TB is zoonotic, the core challenge for eradication in the US is the ongoing wildlife reservoir that sustains transmission across species.