A two-year project to support Mexico’s efforts to control and prevent tuberculosis (TB), to be spearheaded by Richard Garfein, Ph.D., of the University of California, San Diego (UCSD) School of Medicine, has been funded with a $324,810 grant from the United States Agency for International Development (USAID). The project, called “PreveTB” aims to diagnose these infections in vulnerable, hard-to-reach populations and link infected individuals with appropriate treatment programs in order to prevent further spread of the diseases.
“Tuberculosis and other infectious diseases do not respect borders, and our collaborative efforts with Mexican and Californian healthcare providers and health officials will benefit communities on both sides of the border,” said Garfein, associate professor in UC San Diego’s Division of International Health and Cross-Cultural Medicine.
San Diego County reported 305 cases of active TB in 2005, with more than 70 percent of those cases originating from outside the country. The highest percentage of cases from outside of the U.S. originated in Mexico. In Tijuana, there were 480 new TB cases and almost 100 deaths from pulmonary TB reported in 2004.
“The true burden of TB in Tijuana is believed to be much higher, because people who are homeless, sex trade workers or drug users tend to wait until they are much sicker before coming into the clinic,” said Dr. Guadalupe Felix, Director of the State TB program in Baja, Mexico. “We have grave concerns that the rising HIV rate in Tijuana will cause a rise in TB rates as well.”
The UCSD team will work closely with health providers in Mexico to increase the capacity of public and community TB programs in Tijuana to manage the disease. The project’s goals are to provide increased access to services, as well as to collect data about the prevalence of TB in vulnerable populations.
“Through the interactions of the UCSD staff, who are experts in working with high-risk populations, and the Mexican health care workers, who are experts in the care and treatment of TB, we hope that more TB cases will receive treatment more rapidly – giving less time for these patients to spread the infections to others,” said Garfein.
TB is a contagious disease that is spread by people with the active disease in the lungs through coughing, sneezing or even talking. Left untreated, each person with active TB will infect, on average, between 10 and 15 others in a year. In most cases, however, TB is a curable disease. Treatment involves taking oral medications daily for nine months, and the patient is usually not infectious to others within a short time after initiating treatment.
People infected with TB do not necessarily become sick; in healthy individuals, the TB bacilli can lie dormant for years. A person with dormant TB is said to have latent TB infection. But when a person’s immune system is weakened, such as in those infected with HIV, the chance of developing active TB is much greater.
“While those with the latent form of the disease have a one in ten chance of developing active TB over their lifetime, the risk to HIV-infected patients is ten percent each year,” said Garfein. “For this reason, the project will also screen patients for HIV infection. “
The UCSD team is working closely with Dr. Laniado-Laborin, a pulmonologist from Tijuana General Hospital. With funding from the UCSD project, he will establish the first laboratory in Tijuana capable of conducting a blood test to detect TB called QuantiFERON-TB Gold. This test can be conducted in a laboratory, in lieu the traditional TB skin test, which requires injecting TB proteins under the skin, then examining the patient three days later to check for an immune reaction at the site of the injection.
The UCSD researchers are also collaborating with Project Concern International, which runs another USAID-funded project in Tijuana and Mexicali, in order to provide “directly observed therapy” (DOT) to TB-infected participants whenever possible. This approach, in which a health care worker watches the TB patient take his medication each day, can be necessary to assure adherence.
“If a patient frequently neglects to take TB medications on schedule, mutations in the bacterium can develop,” said Garfein. “This makes the strain of TB resistant to the drug in that patient, as well as in anyone else infected by him or her.”
Given that this project takes place minutes from the busiest border crossing in the world, UCSD will also coordinate with the CURE-TB program run by Dr. Kathleen Moser, Director of San Diego County's TB Program. This program aims to improve continuity of care for persons with TB who travel between the United States and Mexico. CURE-TB accepts patient referrals from U.S. and Mexico providers and acts as an information link between them.
Garfein’s project builds upon a current NIH-funded study by UCSD colleague, Steffanie Strathdee, Ph.D., who is studying the incidence and risk factors for HIV infection among 1,000 injection drug users in Tijuana. By engaging individuals from the same neighborhoods, Garfein hopes to demonstrate the feasibility and cost-effectiveness of a mobile clinic model to identify, diagnose and coordinate access to care for TB and HIV cases in high-risk populations in Tijuana.
In 2005, the Centers for Disease Control and Prevention reported 14,093 cases of active TB in the United States. While the overall rate of new TB cases continues to decline in the U.S., the annual decrease in cases has slowed over the past ten years, from 7.1 percent to the current 3.8 percent decline. In addition, an estimated 10 to 15 million people in the U.S. have latent TB. Minorities are affected disproportionately, as TB occurs among foreign-born individuals nearly nine times as frequently.
Additional co-investigators of the “Preve-TB” project include Timothy Rodwell, M.D., Ph.D. and Andrea Mantsios, UCSD School of Medicine, Division of International Health and Cross-Cultural Medicine; Dr. Remedios Lozada, Patronato Pro-COMUSIDA; Dr. Paris Cerecer, ISESALUD; and Dr. Stefano M. Bertozzi, Instituto Nacional de Salud Publica, Cuernavaca, Morelos, México.
Laboratory equipment and technical training provided by Cellestis, Inc., manufacturer of QuantiFERON-TB Gold assays.
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