Global Food

Rapid TB Screening Could Save Human Lives and Reduce Economic Losses to Farmers

By Fran Howard

 Dr. Sylvia Wanzala, a veterinarian from Uganda specializing in infectious disease, is hoping to develop a “bedside,” or point-of-care, test to instantaneously determine whether an animal or human is infected with a zoonotic strain of Mycobacterium, otherwise known as Mycobacterium tuberculosis complex (MTC), a group of agents that cause TB in humans, cattle, and deer.

This quick and inexpensive test would require a drop of blood on a test strip and would be 90 percent accurate in diagnosing MTC in the early phases of infection. It could also be used to determine whether specific treatments are effective in eliminating individual infections, helping to prevent the spread of this deadly disease.

“In rural areas of Uganda, it can take up to three months to find out the results of a lab test for TB,” says Wanzala. “During that time, the disease can spread, and depending on the severity of the infection—which can be further complicated if a person is HIV positive—the patient could be dead by the time the results come back.”

Worldwide, mycobacterial diseases cause human suffering as well as massive economic losses for livestock producers. MTC is major concern in developing countries where livestock are raised in pastoral settings and where humans have frequent and direct contract with their animals. In these areas, it is common for Mycobacterium bovis infections in animals to be transmitted to humans and for M. tuberculosis infections in humans to be transmitted to animals.

“For humans, co-infection with HIV and the increasing worldwide trend of multi-drug-resistant TB further confounds the problem leading to grave animal and public health implications,” she says.

Wanzala’s project, Improved Diagnostics for Mycobacterial Infections in Humans, Cattle, and Wildlife, is currently being funded by a Global Food Ventures award provided by Minnesota’s Discovery Research and InnoVation Economy (MnDRIVE). The research builds on previous work conducted at the College of Veterinary Medicine by Wanzala’s advisor Dr. Srinand Sreevatsan, a professor of infectious disease, and others.

“One of the many challenges in animals and humans is early diagnosis so appropriate treatments can be instituted,” says Sreevatsan. To develop the screening test, Wanzala and Sreevatsan are collaborating on a controlled study with the National Animal Disease Center in Iowa, where serum samples of experimentally infected animals are collected four months post infection.

Wanzala and Sreevatsan are using proteomics—the study of proteins—to identify host response molecules and bacterial molecules in the serum during different phases of the infection cycle. These serum biomarkers, composed of mycobacterial peptides and proteins, are highly specific to mycobacterial infections, and could potentially provide a rapid screening test for the disease.

“One primary reason to go after TB-specific biomarkers is they provide high levels of specificity,” says Sreevatsan. “The skin test used now to diagnose TB in humans can elicit a response to multiple antigens that can be due to other mycobacteria, and it is only about 50 percent specific.”

By contrast, the biomarker assay Wanzala is developing would be about 90 percent accurate and provide a powerful approach to conduct surveillance of mycobacterial infections in livestock in developing countries, where bovine TB is rampant, and in deer, which can transmit the disease to domestic cattle in the United States and elsewhere, causing severe economic losses for livestock producers.

Wanzala earned both her professional and master’s degrees from Makerere University, in Uganda. She also completed a joint Veterinary Public Health residency in applied epidemiology from the University of Minnesota and Makerere University. She also received a Masters’ of Public Health from the University of Minnesota prior to joining the PhD program in Veterinary Medicine focusing on infectious diseases, immunology, and public health at the University of Minnesota.

“This is a very nice project to work on,” says Wanzala, who plans to return to her homeland to continue her work in TB and translational—bench-to-bedside—research. “I want to make an impact, and the translational value of this project is immense.”

Wanzala has been working on this project for two years. Funding for the first year came from the Clinical Translational Science Institute, an initiative funded by the National Institutes of Health.

Global Food Ventures projects, which bring research, agriculture, and industry together to develop holistic approaches to ensuring a safe and sustainable food system, have received more than $4 million in funding from MnDRIVE for fiscal year 2016. MnDRIVE’s Global Food Ventures has funded six new projects in 2016 and renewed funding for nine of the 19 projected funded earlier. MnDRIVE is also funding the research projects of eight graduate students, including Wanzala.

MnDrive is an $18-million annual investment by the state of Minnesota. Global Food Ventures provides awards to scientists in the University of Minnesota’s College of Veterinary Medicine, School of Public Health, and College of Food, Agricultural and Natural Resource Sciences. In addition to Global Food Ventures, MnDRIVE’s research areas are: Advancing Industry, Conserving Our Environment; Discoveries and Treatments for Brain Conditions; and Robotics, Sensors and Advanced Manufacturing.