A team of researchers from the Jawaharlal Nehru University (JNU) has developed new drug molecules against the protozoa that cause amoebiasis.

Context

• Amoebiasis or amoebic dysentery is a common parasitic enteral infection. It is caused by the protozoan parasite Entamoeba histolytica.
• Amoebiasis is present all over the world. Each year, about 40000 to 110000 people die from amoebiasis infection.
• Amoebiasis may present with no symptoms or mild to severe symptoms including abdominal pain, diarrhea, or bloody diarrhea.
• Severe complications may include inflammation and perforation resulting in peritonitis. People affected may develop anemia.
• Types The clinical spectrum ranges from asymptomatic infection, diarrhoea and dysentery to fulminant colitis and peritonitis as well as extraintestinal amoebiasis.
  • Acute amoebiasis can present as diarrhoea or dysentery with frequent, small and often bloody stools.
  • Chronic amoebiasis can present with gastrointestinal symptoms plus fatigue, weight loss and occasional fever.
  • Extraintestinal amoebiasis can occur if the parasite spreads to other organs, most commonly the liver where it causes amoebic liver abscess.
  • Amoebic liver abscess presents with fever and right upper quadrant abdominal pain
    
    

Treatment

• Prevention of amoebiasis is by improved sanitation. Two treatment options are possible, depending on the location.
• Amoebiasis in tissue is treated with metronidazole, tinidazole, nitazoxanide, dehydroemetine or chloroquine.
• A luminal infection is treated with diloxanide furoate or iodoquinoline. Effective treatment may require a combination of medications.
• Infections without symptoms require treatment, but infected individuals can spread the parasite to others.

The findings

• This protozoan is anaerobic or micro-aerophilic in nature such that it cannot survive high concentrations of oxygen.
• However, during infection, it faces a high surge of oxygen inside the human body. The organism synthesises large amounts of cysteine to counter oxidative stress.
• This pathogen deploys cysteine as one of the essential molecules in its defence mechanism against high oxygen levels.
• Entamoeba expresses two crucial enzymes for synthesising cysteine. Researchers from JNU have characterised and determined the molecular structures of both these crucial enzymes.