Biologist Develops Chagas Disease Vaccine

By Nadia Macias

UTEP News Service

In a prestigious journal this year, researchers labeled Chagas disease as the new HIV/AIDS of the Americas. However, the epidemic may soon be facing its end, thanks to a recent development at The University of Texas at El Paso’s Border Biomedical Research Center (BBRC).

Igor C. Almeida, Ph.D., professor of biological sciences, has developed a fully protective vaccine against the parasite that causes the disease – Trypanosoma cruzi or T. cruzi.Igor Almeida, Ph.D., professor of biological sciences, right, and postdoctoral researcher Alexandre Marques, Ph.D., left, have developed a vaccine against the parasite that causes Chagas disease that is fully protective in mice. Photo by J.R. Hernandez / UTEP News ServiceIgor Almeida, Ph.D., professor of biological sciences, right, and postdoctoral researcher Alexandre Marques, Ph.D., left, have developed a vaccine against the parasite that causes Chagas disease that is fully protective in mice. Photo by J.R. Hernandez / UTEP News Service

“Chagas disease has become a world issue,” Almeida said. “Today, people who have it are everywhere – the U.S., Canada, Europe, Japan, and Australia.”

The parasite is initially transmitted to humans via insects known as “assassin bugs” or “kissing bugs” that are predominately found in the Americas.

The insects, which feed on blood, come out at night when their prey is asleep. Unlike mosquitoes that transmit malaria through the bite, “kissing bugs” drop feces on the subject while filling up with blood. After the bite, the spot becomes itchy and subjects scratch the area, moving the contaminated feces into the bite wound, mouth or eye. From there, the parasite penetrates the bloodstream and infects many cells in the body, especially in the heart and gastrointestinal system.

“About 20 percent of patients develop extreme cardiac and gastrointestinal problems,” Almeida said. “The other 80 percent usually don’t feel anything and can die without ever knowing they had it – which is a major issue for public health safety because if you don’t know you have it, you can transmit it to others.”

Once humans have been infected, the parasite can be transmitted to others via organ transplants, blood transfusions and from a mother to a fetus. In addition, the parasite can be spread through foods and juices tainted by the contaminated feces.

“We don’t know why 20 percent develop the major issues,” Almeida said. “It might have something to do with their immune systems. All we know is that 80 percent that are infected are doing very well – it’s like being HIV positive but not having AIDS.”

Today, the chronic infection affects about 8 million people worldwide and is the leading parasitic killer in the Americas, causing about 50,000 deaths a year.

Almeida, who is originally from Brazil, where Chagas disease is considered a major health problem, has been studying T. cruzi since 1990.

While earning his Ph.D. at the Federal University of Sao Paulo under the supervision of Brazilian scientist Luiz Travassos, M.D., Ph.D., he identified the exact sugar molecule in the parasite that the human immune system targets and produces antibodies against – alpha-galactose (alpha-Gal).

Almeida found that these alpha-Gal molecules, which are foreign to the human body, cause the production of anti-alpha-Gal antibodies that cause death to the parasite.

Upon joining UTEP’s BBRC team in 2004, Almeida turned his attention to the creation of a vaccine that would cause the immune system to produce anti-alpha-Gal antibodies.

Along with the help of postdoctoral researcher Alexandre Marques, Ph.D., who has a doctoral degree in microbiology and immunology from The University of Sao Paulo, the two created a vaccine that included alpha-Gal to test on mice that – similar to humans – do not carry the sugar.

According to Marques, who has been working with Almeida since 2007, these mice acted as the “perfect animals that mimic humans regarding this antibody production.”

The test was a success. After being infected with high levels of T. cruzi, the mice had a 100 percent survival rate and showed high levels of anti-alpha-Gal antibodies that were produced to fight off the foreign sugar and could easily kill the parasite.

Both researchers are waiting for funding to continue testing the new vaccine, and hopefully get a pharmaceutical or biotech company interested in producing it on a larger scale.

“It is not every day that a person can change the medical textbooks so completely,” said Stephen Aley, Ph.D., interim dean of the College of Science. “Because of the research of Dr. Igor Almeida, a frequently fatal disease of the Americas has become totally preventable. He is an outstanding example of how UTEP researchers impact millions of at-risk people in this region and throughout central and South America.”

These results come after a long history of working on Chagas disease.

During the late 1990s, using his knowledge of the anti-alpha-Gal antibodies originally developed by Travassos, Almeida was able to co-invent the only test in the world that could both diagnose and follow up potential drug treatment of the disease.

Chagas disease can go undetected easily because early signs and symptoms are similar to common infections. By the time 20 percent of patients develop gastrointestinal and cardiac problems, it’s too late and a heart transplant or major GI surgeries are needed. This makes early detection, or a vaccine to prevent it from ever occurring, extremely important.

“Chagas disease is a neglected tropical disease, affecting millions of people around the globe, and low investment has been made for studies,” Marques said. “It is sad because these diseases are slow regarding the manifestations and they make people suffer for long periods of their lives without efficient treatment.”

Hopefully, that won’t be true for much longer.