Science & Technology
25th Jun, 2020
A team of researchers from the Jawaharlal Nehru University (JNU) has developed new drug molecules against the protozoa that cause amoebiasis.
- 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
What is Entamoeba histolytica?
- According to the World Health Organization (WHO), Entamoeba histolytica is the third-leading cause of morbidity and mortality due to parasitic disease in humans.
- histolytica is classified as a category B biodefense organism because of its environmental stability, ease of dissemination, resistance to chlorine, and it is easily spread through contaminated food products.
- Besides the GI tract, E. histolytica can affect many organ systems.
- 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.
- 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.