For Patrick Cudahy, MD, his interest in HIV was cemented with a research year in South Africa during medical school. There, a widespread HIV epidemic aligned with a tuberculosis (TB) epidemic as well. After seeing firsthand how tuberculosis is the leading cause of death for those living with HIV, Cudahy knew that he wanted to make this co-infection of HIV and tuberculosis the focus of his career.
His year in South Africa was inspired by both mentors and literature. He recalls, “There were a lot of books, like one about Paul Farmer in Haiti called “Mountains Beyond Mountains,” and other things about people doing pretty amazing international HIV work. And so I wanted to see what was out there.” After securing the research opportunity, his time was spent working with an non-governmental organization (NGO) at a massive district hospital, helping improve the hospital operations around HIV and TB, as well as the linkage of care between those diagnosed with TB and their subsequent returns for therapy at the hospital. Tuberculosis takes six consecutive months of treatment. So if they’re started on TB therapy in the hospital, they still need to follow up with their clinic afterwards for a long time.
For any physician, doing research in another country, much less South Africa, is incredibly unique. Cudahy absolutely agrees. “It’s really kind of defined my career. To this day, I spend about 10 months of the year in South Africa and then come back to the U.S. to work at Yale New Haven Hospital. But for me and my family, the bulk of our time is spent in South Africa.”
Unfortunately, COVID’s impact on healthcare, especially on tuberculosis, needs to be monitored. Cudahy says, “Health systems have been doing a lot less testing for TB because of the epidemic, so the diagnoses are down to their lowest level since 2008. And we don’t think that’s because there’s less TB, we think that’s because there’s just less testing being done, and so that means there’s probably a lot more undiagnosed TB out there, which means more spreading and transmission.” With tuberculosis’ latency period of up to two years, Cudahy and his associates will be seeing how COVID has affected the transmission of tuberculosis across South Africa.
However, in the time he spends outside of South Africa, Cudahy works within the group of Ted Cohen, DPH, MD, MPH, a close collaborator with Cudahy’s mentor in South Africa, Douglas Wilson, MBChB, PhD. There, he works at a specialized TB hospital for patients who have drug resistance to tuberculosis - what is called MDR tuberculosis (TB). Patients co-infected with HIV and MDR TB have a very high-rate of death, with up to 20-50% dying before they finish their tuberculosis therapy. Here, Cudahy is mainly focused on working in the hospital to identify markers of those not responding to treatment, as well as trying to find ways to improve their outcomes. What he’s found is that some blood markers, called acute phase reactants (eg. CRP) drop very quickly when the patient is on effective TB therapy. Cudahy explains, “It gives you a nice early signal that someone’s on an effective therapy if those markers drop rapidly.”
Cudahy came to Yale School of Medicine because of their long-standing history of working with South Africa, and has stayed because of his serendipitous connections he’s made with his mentors. Currently in New Haven, he is in the middle of a study looking at more biomarkers of treatment response in MDR TB and HIV. And then, he’s also looking at the genomics of tuberculosis, the differences in strains and the genomes, to see how that affects how patients do with TB. He affirms, “Hopefully with increased sequencing, we can both better predict drug resistance as well as tease out, are there hidden pockets of resistance that we're not detecting with current tests?”
Yale’s Section of Infectious Diseases is an international leader in patient care, research, and education for infectious diseases. Learn more about their work at Infectious Diseases.