Caused by the parasite Trypanosoma cruzi – also known as the ‘kissing bug’ – Chagas disease is frequently referred to as American trypanosomiasis. In the vast majority of instances those affected have no idea they are in fact carrying the disease. It is largely without symptoms in the early stages leading the disease to earn the name ‘silent killer’.
Though it can go undetected for some time and present no obvious symptoms, the infection will remain present and intensify over the patient’s life and can prove fatal without treatment.
Chagas disease was originally confined to rural areas in Latin America though has been transported around much of the world in line with ongoing population movements. Across Mexico, Central America and South America, official government figures estimate that around 8 million people have been infected.
Chagas disease may not be endemic in the United States for example, though cases quickly grew and reached particular prevalence in 2014. This surge in numbers led to a step-up in national focus on prevention of the disease’s further spread, with most cases having been detected in southern states.
The disease itself is the result of T. cruzi parasites being passed from bugs to humans. When the insect vectors called triatomine bugs are infected with the parasites, they emit living T. cruzi parasites during defecation. The bugs are relatively common in certain types of homes and dwellings, including those made using mud, adobe, straw, and palm thatch.
Nocturnal in nature, the bugs sleep during the day and come out at night while the home’s occupants are sleeping. It’s at this stage that they feed by biting the faces of humans while they sleep the reason they’re also known as ‘kissing bugs’. After feeding, the bugs defecate on the faces of the humans which summarily passes the parasites onto their skin. The parasites may then travel into the body via mucous membranes, small wounds or any other openings – eyes, mouth, nose etc.
This tends to be the most common way in which Chagas disease is picked up directly from its source origins, though there are other ways it can be transmitted including the following:
- Transmission from a mother to her unborn baby, who then may be born with Chagas disease
- Transfusion of contaminated blood
- Transplantation of an organ originating from a person with Chagas disease
- Sexual transmission via bodily fluids
- Consumption of food or liquid that has not been properly cooked and contains the parasites
- Exposure to blood or excretions of an affected patient
Concerns over the possible spread of Chagas disease to infants by way of breastfeeding were toned down somewhat, with research having suggested that the child would only be at risk if the nipples were cracked or bleeding.
Generally speaking, the transmission risk from person to person by way of standard everyday contact and interaction is zero – it is not airborne and cannot be spread in the same manner as the flu or the common cold.
Family Risk Factors
If a member of any family is confirmed as having Chagas disease, it’s important for other family members to undergo testing if:
- They have been exposed to the same source/point of infection
- Have been given a blood transfusion or organ donation since infection
- Were born when one or both parents may have had Chagas disease
- Have practiced unsafe sex since infection
Signs and Symptoms
Both stages of Chagas disease – the acute phase and chronic stage – can be symptomless or life-threatening. However, the majority of cases are largely symptom-free in the early stages at least.
In the early acute stages of the disease, the patient may go for several months without noticing any problems. When symptoms do present, they are often written-off as being caused by something else and far less problematic – patients may experience:
It is only by being examined that other signs and symptoms can be picked up, which may include swollen glands, liver enlargement and swelling around the parasite’s point of entry. In addition, one of the most common tell-tale signs of Chagas disease is moderate to severe swelling of the eyelids.
Even the more severe symptoms may disappear without medical intervention over time, but the parasite will remain within the patient’s body and their condition will gradually worsen. After several years or decades, the chronic stage may present more life-threatening symptoms and complications, which can include:
- Heart failure
- Cardiac arrest
- Enlarged heart
- Erratic heart beat
- Enlarged esophagus
Around 30% of Chagas disease patients develop at least one of the above complications.
Treatment and Prognosis
Chagas disease can be treated most effectively when caught early, so it’s a good idea never to overlook any potential risks. The treatment process itself is carried out using an antiparasitic treatment to kill the parasite itself, followed by additional treatments to combat any residual infection and to alleviate any symptoms. While the parasite can be killed off using a medicinal treatment that requires no hospitalization, those with more advances cases of Chagas disease may find themselves in need of heart medication for life or may be fitted with a pacemaker.
As there are no specific vaccines or wholly effective preventative measures to take against Chagas disease, those travelling to high-risk areas are advised to choose high-quality accommodation and to sleep on a raised bed while using an insecticide-treated mosquito net. In addition, all possible transmission threats including those of bodily fluids should be avoided altogether.