US [government] Sponsors Ambitious Study of TB Transmission in Peru

Researcher Leonid Lecca states this is the largest TB study ever conducted anywhere in the world, with $6 million in funding. 

Wednesday August 3, 2011 – 12:32 p.m.



Online Edition

Socios En Salud Perú, an affiliate of the highly regarded medical organization Partners In Health, has for a year been conducting an ambitious study that aims to determine precisely how tuberculosis is transmitted. Although it is well-established that overcrowding and poor diet contribute to TB transmission, particularly in poor neighborhoods, the study “Epidemiology of Multidrug-Resistant Tuberculosis in Peru (The EPI Project) examines a broader question and seeks to ascertain why some people have greater resistance to infection than others. 

“We want to understand why some people contract tuberculosis while others who live in the same home and eat the same food don’t; why some appear to have greater resistance [to the illness] than others; why some don’t become sick for one to two years while others have TB symptoms just weeks or months after their first contact with an infected person,” explains Dr. Leonid Lecca, the study’s Principal Investigator in Lima. The need to find answers to these questions is the basis for this project, which is financed by the US National Institutes of Health, specifically by the Division of Microbiology and Infectious Diseases of the National Institute of Allergy and Infectious Diseases. The project’s Principal Investigators are Drs. Megan Murray and Mercedes Becerra of Harvard University, who proposed conducting the study in Lima, Peru and secured the multimillion-dollar grant to fund it. Socios En Salud has received six million dollars to carry out the project. 


With 32,000 new TB infections, Peru has one of the highest burdens of the disease in Latin America. Although it is painful to admit this, the country is therefore the ideal environment in which to conduct such an ambitious study (El Comercio has published multiple reports on TB in Peru).  Dr. Lecca asserts that measured by the numbers of subjects to be enrolled, the size of the project’s staff and its funding, this is the largest TB study ever conducted anywhere in the world.

“We are attempting to enroll 4,000 TB patients and everyone who lives in their households in the study. Patients may live with as many as five people, so we’re talking about a study of more than 15,000 people,” he explained. The project’s staff consists of nearly 200 people, among them doctors, nurses, nursing and lab technicians, etc.


The study’s objective directs its focus not to TB patients, but rather to the people who live with them since the goal is to learn which factors contribute to infection and which confer greater resistance [to the illness]. To that end, study teams contact patients through health centers run by the Ministry of Health, which serves as a partner in the project, and then visit their homes to enroll them and other household members in the study.

Dr. Lecca elaborated, “We need to find answers that help us understand TB transmission. The only way to do this is through prospective follow-up of TB patients and people who live with them (following them over time). So when the Ministry of Health diagnoses a TB case in a health center, we look for that patient’s household members. We find healthy people who have been in contact with the TB bacilli, or others who have symptoms; the latter then require a thorough evaluation to diagnose if they have TB. The goal is to identify when these healthy people are infected with TB and with what type of TB.”


However, this project serves not merely as a witness to TB transmission. When a person who may have TB is identified, he or she is referred to a health center to screen for infection and the disease (which are two distinct stages). The Socios En Salud study team also screens for TB infection using PPD testing and requesting sputum specimens from people with respiratory symptoms so that the TB bacilli may be isolated and tested. The study also provides chest x-rays to screen for disease and offers HIV testing to all subjects.

“The study works with the Ministry of Health to identify people in the community with respiratory symptoms and helps achieve timely diagnosis of TB. People go to a doctor as soon as they feel sick, but this study speeds up the identification of these people by referring them promptly to health centers for treatment. This study encompasses service, training, and research,” Dr. Lecca explained.


The study is being conducted in the DISA V region of Lima, in districts that include Rímac, San Martín, Los Olivos, Cercado, La Victoria, Lince, San Luis.

When data collection is completed, the researchers will conduct an analysis and publish their conclusions, sharing them with the global scientific community in the hope of reducing the spread of this disease that affects millions of people around the world.

Oswaldo Jave Castillo, who directs Peru’s National TB Program, believes that this study, “will add to the knowledge” that his institution uses to carry out its mission. He explained, “Knowing how frequently contacts (of TB patients) are infected and at what point will allow us to adapt some of our interventions, such as how many times a year we should test the household contacts of TB patients for the disease.


The areas in metropolitan Lima with the highest number of TB cases are La Victoria (San Cosme, El Pino), Cercado de Lima and San Martín de Porres.

There are three types of TB: simple or drug-susceptible TB, multidrug-resistant TB (MDR-TB), and extensively drug-resistant TB (XDR-TB). MDR-TB is resistant to two drugs used to treat the disease. Eighty-two percent of MDR-TB cases in Peru are in Lima. Nearly all the drugs used to treat MDR-TB are imported. XDR-TB is resistant to five anti-TB drugs. Ninety-three percent of XDR-TB cases in Peru are in Lima. The first XDR-TB cases in Peru were detected in 1999 and today number 341.  According to the World Health Organization, in 2009, TB killed 1.7 million people (380,000 of whom had HIV).