How infectious diseases compete for red blood cells in the human body: Study

Malaria and soil-transmitted worm infections are two of the most common and co-occurring types of human infectious diseases, yet how they interact with each other remains unclear, until today. A study has revealed why co-infected patients got sicker after being dewormed. Findings of the study were published in Ecology Letters.

  • An international team of researchers looked at the data from an Indonesian study wherein 4,000 individuals who had two parasitic infections, malaria and hookworm, participated.
  • The team concentrated on malaria patients who had also received deworming treatment.
  • Researchers discovered previously unknown interactions between the species.
  • As a result, they found that malaria parasites and some worms are ecologically in a similar place to herbivores.
  • They found that the parasites in the body compete for red blood cells for resource.
  • Similar to how herbivores depend on plants for food, malaria parasites and hookworms also depend on resources below them on the food chain, which are the red blood cells. Moreover, the “predator” for malaria parasites and hookworms is the immune system.
  • The removal of worms from patients who also had malaria triggered their malaria to grow to almost three times higher densities.
  • In contrast, the existence of the bloodsucking worms decreased the density of malaria parasites by more than 50 percent.
  • This means that deworming can worsen infections due to malaria, which in turn potentially leads to more severe symptoms and increases the risk of spreading malaria to other people.

In conclusion, the findings suggested that the absence of hookworms increases the density of malaria, making the infected person sicker.

Journal Reference:

Budischak SA, Aprilianto WE, Hamid F, Wammes LJ, Kaisar MMM, van Lieshout L, Sartono E, Supali T, Yazdanbakhsh M, Graham AL. COMPETING FOR BLOOD: THE ECOLOGY OF PARASITE RESOURCE COMPETITION IN HUMAN MALARIA-HELMINTH CO-INFECTIONS. Ecology Letters. 2018; 21(4). DOI: 10.1111/ele.12919

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