Man vs. Amoeba (SSAWRN)

Alan Anderson

Justine (pronounced Justin) Ekou is a friendly but determined young man who grew up with few advantages in a small village in eastern Uganda. His parents were poor farmers who scraped a living from the dry soil, growing and selling cassava, sweet potatoes, millet, and sorghum. He was sent to school in the district capital of Soroti until grade 7, when his parents could no longer support his education. Luckily a paternal uncle stepped in to sustain his momentum through high school. The instruction level was basic; “we had no textbooks at school,” he said. But he applied himself and brought home excellent grades.

When his sister fell ill with the intestinal parasite Entamoeba histolitica, whose incidence is second only to malaria among severe illnesses in Uganda, he resolved to keep studying in order to join the battle against this debilitating disease.

The next step came easily when he qualified for a government scholarship to Makerere. He had his heart set on medicine, but this route was too competitive for someone with only a basic education. He decided to enter veterinary medicine instead, with the hope of helping humans as well as livestock.

After graduating in 2007, he took a year to gain practice by working for several firms that offered large-animal vet services (there is little small-animal veterinary work because few people in Uganda keep small animals as pets). He returned to Kampala to meet with the department head, who encouraged him to go on to an MSc even though he could not afford the fees. Justine was determined to learn about molecular biology, because he was convinced that the answers to disease lie hidden at that level.

He persisted and finally found a scholarship, where he immersed himself in molecular studies. But when it came time to move toward a PhD, Justine was stumped. He repeated the strategy that had brought him luck before, making the rounds of the many departments in the Faculty of Veterinary Medicine. Finally, he found Prof. Michael Ocaido in the Department of Wildlife and Animal Resources Management and heard some good news.

“I told Prof. Ocaido that I urgently wanted to study water-borne diseases,” he said, “because my village has such big problems – typhoid, dysentery, and cholera in addition to amoeba.” Even though Prof. Ocaido has spent his career in the veterinary medicine department, he was sympathetic to Justine’s obvious desire to improve human health, so he told him about the new RISE program. The department wanted to make use of Justine’s strong background in molecular biology and asked him to develop a proposal. He came up with a plan to sample amoebae at four sites in Uganda, where he would apply type analysis to the genome. This would allow him to test at each location whether the genetic type present in the water supply is the same as the type in infected patients.

As Justine prepares for his field work, he will need all the modern tools he can bring to the task, since the amoeba turns out to be as enigmatic as it is debilitating. “Humans carry many strains of amoeba, but only about one in 10 cause disease. Why? Very little is known about this in Uganda. We are more or less starting from scratch.

“Also, people are discovering that there is a strain of this organism that invades the liver and lungs. This is a separate species called E. dispar, which is very hard to diagnose. It can’t be differentiated from E. histolitica by regular microscopy.” A consequence of this is that conventional assumptions – and public health data – may be off. Justine will have an advantage in using his genetic tools, which should bring him new information about this tricky pathogen.

“Many people thought to have histolitica may in fact have dispar,” he said, “which may be even more prevalent but doesn’t cause gastrointestinal disease. So we have a lot of work to do.”