World Chagas Disease Day has passed, but the disease is still there

Translator's note: April 14, 2022 is World Chagas Disease Day. April 14, several days have passed in a blink of an eye. World Chagas Disease Day has passed, but the disease is still there. The pain that the disease brings to patients is still there. The One Health Working Group of the China Biodiversity Conservation and Green Development Foundation (hereinafter referred to as China Biodiversity Conservation and Green Development Foundation, CBCGDF) continues to pay attention to the spread of this disease in Latin America and the great pain it brings to people. In August this year, China Biodiversity Conservation and Green Development Foundation will send a working group to Latin America, go deep into Latin American communities, conduct field research, and start another new journey of the China Biodiversity Conservation and Green Development Foundation's South-South Big Science Program (SSBSP).

This year, the United Nations World Health Organization proposed that the theme of World Chagas Disease Day is to find and report every case to defeat Chagas disease (also known as American trypanosomiasis). In 2022, WHO will focus on Chagas disease and the suffering it causes, and call for fair access to health care and services for everyone affected by the disease. In many countries, detection rates are low (less than 10%, often less than 1%), and various barriers are often encountered in the process of obtaining appropriate health care. Chagas disease is very prevalent among poor people in Latin America, but more and more cases are being found in other countries and continents. The disease is often called a "silent disease" because most infected people have no symptoms or very mild symptoms. About 6 million to 7 million people are infected with Chagas disease worldwide, with 30,000 to 40,000 new cases each year, of which 10,000 people die each year.

Chagas disease, also known as American trypanosomiasis, is a potentially life-threatening disease caused by the protozoan parasite Trypanosoma cruzi. Chagas disease, also known as American trypanosomiasis, is a potentially life-threatening disease caused by the protozoan parasite Trypanosoma cruzi (T. cruzi).

It is found primarily in 21 Latin American countries, where it is primarily vector-borne. The main vector that transmits this parasite to humans is Trichodina, also known as the "kissing bug." An estimated 8 million people are infected worldwide, mostly in Latin America. Chagas disease is clinically curable if treatment is started early. Therefore, universal access to timely diagnosis and care is critical.

About Chagas Disease

Once entirely confined to the Americas, Chagas disease has spread to other continents over the past century, largely due to improved travel and the movement of global populations in and out of Latin America.

It is estimated that more than 10,000 people die each year from clinical manifestations of Chagas disease, and more than 25 million people are at risk of contracting the disease.

Vector control remains the most useful method for preventing infection. Blood screening is essential to avoid transfusion and organ transplant infections. Screening and diagnosis of pregnant women and their children are essential control measures.

Chagas disease is named after Brazilian physician Carlos Chastiniano Chagas, who discovered the disease in 1909.

Chagas disease vectors belong to the order Hemiptera (adults have wings and fly), the family Rudinae and the subfamily Mylochaetinae (all feed on blood at all stages of their development), primarily from the genera Mylochaete, Panspermum and Rudinae, but also from 12 other genera.

In the Americas, Chagas disease is spread by several species of three-lined bugs, which commonly live in the cracks of poorly built homes in rural areas and suburban slums in Latin America.

These bugs hide during the day and come out at night to suck blood from people, usually while they sleep. Other infected three-lined bugs may be found around homes and in the wild. Therefore, the exchange of infection is possible in this environment.

Disease distribution

The distribution range of the American Trypanosoma cruzi vector and wild hosts extends from the United States of America to Argentina and Chile (46°N to 46°S). Three-lined bugs are also found outside the Americas, but to date, none have been found to be infected.

More than 150 species of three-lined bugs and more than 100 mammals (mostly wild species) maintain Trypanosoma cruzi infection in nature.

Because the reservoir is so extensive, Chagas disease is incurable.

The vector was first described by Swedish scientist Charles De Geer in 1773 through observations of insects captured in the ancient so-called "Indies" (assumed to refer to the East Indies, possibly Indonesia).

Since the 18th century, species of Trypanosoma tridentata with the ability to transmit Trypanosoma cruzi have been found along sea travel routes to Africa, the Middle East, Southeast Asia, and parts of the western Pacific.

Increased global population mobility increases the likelihood of vector transmission to areas where Chagas disease was not previously endemic, particularly in Asia, where the vector is naturally abundant and has even invaded homes in large numbers.

How to spread?

In the Americas, Trypanosoma cruzi is primarily transmitted to humans through the infected feces of blood-sucking Trichodina, a vector of the disease. This insect usually hides during the day and becomes active at night when it feeds on human blood. In its quest for a blood meal, the bug typically bites exposed areas of skin (such as the face—hence its English name, the "kissing bug").

Just after taking its blood meal, it defecates near the bite site. The parasite is present in the bug's feces and is transmitted when people, in an instinctive response to itching (caused by the bite), rub the bite site, thus allowing feces to come into contact with the bite. The parasite can also be transmitted when it comes into contact with the eye or oral mucosa, or through any other skin lesion. Transmission can occur through contaminated food infected with the vector's feces. This frequently results in oral disease outbreaks, especially in hot, humid climates. Other routes of transmission include transfusing contaminated blood from an infected mother to a child during pregnancy or delivery (congenital transmission). Less frequently, transmission can occur as a result of an organ transplant or laboratory accident. Outside the Americas, transmission is not through the feces of an infected vector, but rather through non-vector routes. Cases of infection outside Latin America have been reported among travelers, adopted children, and immigrants returning from endemic areas. Globalization and increased international travel and trade between endemic and non-endemic countries have made Chagas disease a growing concern worldwide.

See original text:

https://www.who.int/en/campaigns/world-chagas-disease-day/world-chagas-disease-day-2022

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Compiled by: Daisy

Reviewer: Lucy