A new strain of tuberculosis (TB) has emerged in recent years that is resistant to almost all drugs used to treat the disease, raising concerns that the strain will potentially harm global efforts to contain and eradicate TB.
Extensively drug-resistant tuberculosis (XDR TB) is a rare form of multiple drug-resistant tuberculosis (MDR TB). MDR TB emerged during the 1980s when patients showed signs of resistance to the two primary first-line drugs used to treat TB: isoniazid and rifampin. XDR TB is a step further in resistance to drugs used to treat the disease, as those with the strain are also resistant to the best second-line medications, such as fluoroquinolones, amikacin, kanamycin, and capreomycin.
Concerns were increased in 2006 following a report by the Centers for Disease Control and Prevention (CDC) that indicated that the number of patients infected with the new strain of XDR TB had increased from three to 11 percent, based on surveys from TB labs on six continents. The new strain XDR TB has appeared in at least 37 countries around the world, including the United States. According to the CDC, 49 cases of XDR TB emerged in the US between 1993 and 2006. Medical experts have stated that approximately 50 percent of those who contract the new strain will likely die.
Potential Threat to the US
While the potential for contracting XDR TB in the US is relatively low, TB can quickly spread. If an individual who is infected with TB of the lungs or throat coughs, sneezes, speaks, or sings, those who breathe in the air infected with the germ may contract the disease.
Of particular concern are individuals residing in the US who have contracted the disease while in their home country and have not undergone adequate treatment and remain contagious. Several countries have a large number of individuals who are infected with TB, such as Russia, China, and many throughout the African continent. According to a study conducted by federal and state health officials in 2005 that focused on the state of California, a large portion of drug resistant TB cases were reported in patients from the state’s “foreign-born” population, primarily in those from Mexico and the Philippines. The study also indicated that of the 15,000 cases of TB reported throughout the US in 2004, 53 percent of patients were considered foreign-born individuals.
Infection Case Documents Concern
One recent case has sparked debate in the US regarding what measures officials should take to protect the American public from those infected with XDR TB. Robert Daniels, a dual Russian-US citizen, contracted TB while in Russia and later traveled to the US. Daniels’ form of TB mutated into XDR TB and he was diagnosed with this new drug resistant strain while in Phoenix, Arizona. In addition to receiving medication to ease symptoms, Daniels was instructed by doctors to wear a mask if in public and stay indoors as much as possible. However, according to authorities, Daniels was seen in public several times without a mask, prompting medical officials to obtain a court order that placed Daniels in isolation in a prison wing of an area hospital. The case has resulted in debates on how to protect individual rights while simultaneously protecting the public.
TB as a Possible Weapon for Bioterror
Officials remain concerned that terrorists could potentially employ TB as a weapon in a bioterror attack. Specifically, with the drug resistant strains of the disease, the possible effects of using such an agent would be widespread and potentially deadly. There are several possible methods extremists could use to carry out such an attack, to include placing an infected individual in a confined space, such as on an airplane, or releasing samples of TB into the air.
Future Implications
With cases of XDR TB slowly increasing around the world, the need for further research and studies on the disease is apparent, as continued expansion of the new strain of TB is a significant threat. Several medical officials have already warned that if this new strain is not contained, the potential remains for the disease to mutate into a completely drug resistant form of TB, which would have devastating consequences.
