The 'Silent Killer' Thought to Be Gone Spreads Rapidly... US Health Authorities on High Alert

South American Endemic Disease: "No Longer an Imported Illness"
Spread by Kissing Bug Bites While You Sleep

Recently, as Chagas disease, known as an endemic illness in South America, has been rapidly spreading in the United States, health authorities have raised their alert level.

Local media reported that the US Centers for Disease Control and Prevention (CDC) announced on the 5th (local time) that "patients with Chagas disease have been found in at least eight states" and stated, "It should no longer be considered a foreign disease, but recognized as a domestic infection within the United States." In particular, it is estimated that the number of infected individuals in California could reach between 70,000 and 100,000.

Chagas disease is primarily transmitted by blood-sucking assassin bugs, commonly known as "kissing bugs." These insects bite a person's face, especially around the mouth and nose, at night and then defecate; the excretions can enter the body through wounds or mucous membranes, leading to infection. The disease can also be transmitted from a pregnant woman to her fetus through the placenta, as well as through organ transplantation or blood transfusion.

Blood-sucking assassin bug transmitting Chagas disease. Screenshot from the World Health Organization website

According to Asan Medical Center in Seoul, the incubation period for Chagas disease is typically 12 weeks. Initial symptoms may include fever, fatigue, and rash, but most people do not notice any unusual signs. Some patients with acute infection may experience swelling around the eyes or severe swelling at the site of the bite, but only about 20% show noticeable symptoms.

The problem arises when the disease becomes chronic for several years or even decades. Between 20% and 30% of those infected develop heart or digestive diseases. Symptoms such as cardiac enlargement, arrhythmia, heart failure, and stroke may occur, and abnormal enlargement of the esophagus or colon (megaesophagus or megacolon) can also appear later. In fact, about 30% of patients suffer from severe heart disease, and symptoms can emerge even decades after infection.

Currently, two antiparasitic drugs, benznidazole and nifurtimox, are approved as treatments; however, the cure rate varies greatly depending on the stage of infection, and no vaccine exists yet. In particular, infected children face a higher risk than adults, which can lead to death. Chagas disease is most prevalent in Central and South America, including Brazil, Chile, Argentina, and Mexico. It is estimated that there are 6 to 8 million infected people worldwide, with approximately 50,000 deaths annually.

Experts have urged the establishment of an early diagnosis system, noting that "many doctors in the United States do not consider Chagas disease." Professor Norman Beatty of the University of Florida emphasized, "Chagas disease is a 'silent killer' and a forgotten tropical disease in the United States. It is crucial to take preventive measures in daily life, such as keeping the area around the home clean, removing woodpiles and clutter, sealing cracks in doors and windows, installing screens, and using insecticides."