Chagas disease

  • caused by Trypanosoma cruzi  parasites, inside the heart and digestive muscles
  • causes cardiac disorders or digestive alterations in 40% of patients
  • can lead to death or heart failure due to progressive destruction of the heart muscle and its nervous system
  • chronically infects 6 – 7 million people, mostly in South and Central America

American trypanosomias – also known as Chagas disease – is caused by infection with Trypanosoma cruzi, a protozoan parasite. The disease is named after Carlos Ribeiro Justinanio Chagas, who discovered it in 1909. The disease burden is substantial: T. cruzi causes 7,000 deaths per year as well as life-long morbidity and disability, and costs an estimated US$ 7 billion per year,1 including lost productivity. The World Health Organization (WHO) estimates that over 25 million people are at risk of infection.1

Infected blood-sucking triatomine bugs, widely known as ‘kissing bugs’, transmit the disease.2 These bugs typically live in the cracks of poorly-constructed homes. Other modes of transmission include consumption of contaminated food, blood transfusion, organ transplantation, or passage from an infected mother to her newborn. The disease has two clinical stages: acute (in which 5% of children die) and chronic. Symptoms include fever in the acute stage, and cardiac disorders or digestive alterations in the chronic stage. 

T. cruzi also infects a large number of wild animals, which means that the parasite cannot be eradicated. Instead, control of Chagas disease focuses on elimination of transmission, and on healthcare access for the infected population. The only drugs currently available to treat those infected are benznidazole and nifurtimox. Both are effective in the early (acute) phase of the disease, but they are limited in their capacity to eliminate T. cruzi from chronically infected patients3. Furthermore, resistance to these drugs has been reported, and a further complication is the diversity of strains over the vast geographical area in which the disease is endemic.4

The WHO stresses that the benefits of medication should be weighed against possible adverse reactions (occurring in up to 40% of patients) and the duration of the treatment (up to two months).3  The PDE4NPD consortium therefore aims to find and develop more effective drugs against Chagas disease with limited adverse reactions. 

References and further reading:

  1. World Health Organization: Third WHO report on neglected tropical disease
  2. Centers for Disease Control and Prevention: Chagas Disease life cycle
  3. World Health Organization: Chagas Disease fact sheet
  4. Filardi and Brener, Susceptibility and natural resistance of Trypanosoma cruzi strains to drugs used clinically in Chagas disease, Trans. R. Soc. Trop. Med. Hyg. 1987