Researchers from UMass Medical School and Cornell University have sequenced the genome of the hookworm Ancylostoma ceylanicum, a development that could lead to new treatments for parasitic hookworm.

Necator americanus
Necator americanus (hookworm)

The study, which also includes researchers from the University of California San Diego and the California Institute of Technology, was published in Nature Genetics.

Contemporary efforts to study the parasitic nematode have been hampered because the most common species, Necator americanus and Ancylostoma duodenale, cannot survive outside of a human host. This makes it difficult for researchers to study them in the lab and almost impossible to test new drugs and vaccines. It is why current treatments rely on drugs developed to treat similar worms in farm animals.

“The health burdens associated with soil-transmitted hookworms, especially in developing countries in Africa and the tropics are enormous,” said Raffi V. Aroian, PhD, professor of molecular medicine and co-author of the study. “The only drugs we have to combat these parasites were developed to treat farm animals and are only partially effective. There is a tremendous need for a treatment for hookworms in humans that is safe, effective and affordable in the world’s poorest countries.”

Read the rest of the UMass Medical School news release HERE

Hookworms are the second most common intestinal roundworm in humans worldwide, with an estimated half a billion people infected at any one time.

You get hookworm in areas of unsanitary conditions where people defecate on the ground and the climate is favorable. Warm, moist climates and sandy soil are the environments hookworms thrive in. Infective larvae can survive up to a month in the soil under ideal conditions.

Hookworm is not an issue in cold climates because the larvae cannot survive.

People get infected by walking barefoot over contaminated soil where the hookworm larvae can penetrate the skin. It is a particular problem in farmers in developing nations worldwide. Also, small children get it by sitting bare-butt on the ground that has hookworm.

Ancylostoma duodenale may also be acquired orally, transmammary and transplacentally.

After the larvae penetrate the skin, it is carried in the bloodstream to the heart and then the lungs. Here they climb the windpipe and are swallowed to the intestines where they mature to adults.

In the intestines, the adults attach and suck blood. The blood loss can be significant depending on the amount of worms present. A. duodenale drinks more blood per worm (0.2-0.3 ml) per day than N. americanus (0.03 ml), and are therefore more pathogenic.

The symptoms you may see depends on what stage of infection the person is in. During invasion when the larvae initially penetrate the skin, there may be a severe allergic reaction known as “ground itch”.

While the larvae are migrating through the lungs, an infected person may experience a mild pneumonia with a cough.

When adults are in the intestines, symptoms may include diarrhea, pain, and nausea.
In very heavy infections, blood loss can reach 100 ml per day resulting in iron deficiency anemia and weakness due to blood loss.

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In addition, protein deficiencies, enlarged liver and spleen and developmental disorders like mental, physical and sexual may occur in severe hookworm disease.

People can be infected by animal hookworms, but most just penetrate the skin and wander in tissue just below skin (cutaneous larval migrans). They cannot complete their life cycle and do not cause hookworm disease.