Chagas Disease: Causes, Symptoms, and Treatments
Medikoe Health Expert
Koramangala, bengaluru, karnataka, india, Bengaluru Feb 9, 2017
Also known as American trypanosomiasis, this is a contagious disease caused by Trypanosoma cruzi (T. cruzi) a parasite that causes Chagas. If not treated immediately, this disease could pose a threat to the patient’s life.
This illness is mainly found in people living in Latin America and also some parts of the United States. Due to people migrating, over time, the disease has now spread worldwide and isn’t only confined to America. It is prevalent in areas with poor living conditions.
Over 6 to 7 million people all around the world are infected by T. cruzi. The parasite is transferred when humans come in contact with faeces or urine of triatomine bug, which is more commonly known as kissing bug.
Once the symptoms progress, the disease manifests as a chronic heart, digestive or neurological disease, or in a mixed form and could sometimes end in death.
The disease is named after Carlos Ribeiro Justiniano Chagas, a physician from Brazil who discovered the disease in 1909.
Causes of Chagas Disease
People contract T. Cruz infection when bitten by the triatomine bugs or kissing bugs, which acts as a vector for the parasite. Transmission occurs when humans come in contact with faeces or urine of the blood-sucking kissing bug.
These bugs come out during the night time and bite the exposed areas of human skin, after which it urinates or excretes at the bite site. The parasite finds a way into the human body when the excreta or urine is smeared into the bite or broken skin like cuts, open wounds, etc.
Transmission can also occur if the person,
Consumes food contaminated with T. cruzi
Underwent a recent transfusion and received blood from an infected donor
Received an organ transplant from an infected donor
Present during any laboratory accidents and comes in contact with the parasite.
Contracts the infection congenitally, i.e, if the mother was carrying the parasite during pregnancy.
Risk factors of Chagas Disease
A lot of factors could cause a person to contract Chagas disease. People have a high risk of contacting T. cruzi infection if,
They reside in rural areas of Latin America and is accustomed to poor living conditions
Reside in houses with a thatched roof or walls that have cracks or crevices where the bugs can hide during the daytime
Have noticed the presence of kissing bugs in the are they live.
Chagas Disease Symptoms
Once the bug is transmitted the patient goes through two stages of infection.
The first phase of infection is called the acute phase. This phase lasts for a couple of weeks or for as long as two months. A person with acute infection has the T. cruzi parasite circulating in their bloodstream. During this phase, the patient might show mild symptoms or no symptoms at all.
Initially, when a person is bitten by the bug, he or she will show signs like a lesion in the skin, purplish swelling at the bite site and also swelling in one of the eyelids. Other mild symptoms include fever, tiredness, body pain, headache, loss of appetite, diarrhoea, vomiting, enlarged lymph vessels, pale skin, swelling, and chest or abdominal pain. In rare cases, people could have severe inflammation of the heart muscles or the brain while being acutely infected.
The acute phase is then followed by a prolonged phase where the patient shows no symptoms at all. During this phase, there is a minor presence of the parasite in the blood or no presence at all; due to which the disease goes undetected. This phase of infection is called chronic indeterminate, and most people remain in this phase.
But 20 to 30% of the population have the parasites reaching vital organs like the heart, and parts of the digestive system such as oesophagus and colon. This phase affects the cardiac system, digestive system, neurological system or in some cases, a mix of these organ systems.
When the patient’s digestive organs are affected he’ll face dIfficulties in eating or passing stool due to dilated oesophagus or colon
In extreme situations, it may lead to death because of cardiac arrhythmias or progressive heart failure as a result of the destruction of muscles in the heart and nervous system.
A person who is infected need to be treated as soon as possible or infection stays life long. People who have weak or suppressed immune systems, the parasites can reactivate in the blood even after the acute phase causing severe diseases.
Diagnosis of Chagas Disease
It’s easy to detect if a person has Chagas disease during the acute phase as the parasite will be seen circulating in the blood. A thick and thin blood smear is stained and observed to check for the presence of the parasites.
Once in its chronic phases, it cannot be detected in the patient’s blood. The only way to diagnose is to consider the patient’s symptoms and then compare it to the environmental conditions he or she was subjected to.
To confirm the diagnosis, the patient is tested for antibodies that are specific to parasites.
Treatment of Chagas Disease
It is possible to treat and cure the T. cruzi infection if it is detected as soon as the patient is bitten. Although it is not curable once it reaches the chronic phase, providing anti-parasitic treatment could prevent the disease from progressing.
Should the patient have their organs affected, then treatment is devised based on the organ system affected.
Prevention of Chagas Disease
Various public health organisations have worked on preventing the transmission of the T. cruzi parasite by disinfecting possible bug-residing areas so that people are not bitten. This has reduced the number of transmissions, but congenital transmissions still occur.
Organisations now screen donated blood for the parasite before it is transfused into another body.
New-born babies of infected mothers are all tested for the parasite.
It’s hard to prevent the transmission of T. cruzi as these parasites not only infect humans but also a large population of animals. In fact, initially only wild animals were infected, then it spread on to domestic animals and humans. Since it is prevalent in animals, the parasites cannot be completely eradicated.
Transmission can be prevented by,
Spraying insecticides and protecting the house from a bug infestation,
Preventing being bitten by putting on bednets
Practise good hygiene when it comes to preparation, transport, storage and consumption of food
Screening blood and organ donors
Start antiparasitic treatment
Create facilities that help detect the infection early on
Implement control strategies to prevent transmission
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