What Pharmacists Should Know as Chagas Disease Circulates in the US

Health officials across the US are raising concerns as cases of Chagas disease—a serious parasitic infection—establish themselves in California and Southern states. Previously, Chagas disease was considered nonendemic and did not regularly circulate in insect populations in the country, but rising cases are challenging this label.¹ Despite the growing risk, many Americans are unaware of what Chagas disease is, where it comes from, and what it looks like.

Image of a kissing bug | Image Credit: © Sigit - stock.adobe.com

What is happening in the US?

According to state reporting from the Los Angeles Times, California has the highest number of human cases of Chagas disease, at anywhere between 70,000 and 100,000. Other human cases have been reported in Arizona, Texas, Louisiana, Missouri, Tennessee, and Arkansas. Animal cases were reported across these states, as well as in New Mexico, Oklahoma, Kansas, Kentucky, Maryland, Virginia, North and South Carolina, Florida, Alabama, Mississippi, and Georgia.^2,3

Kissing bugs, insects that carry Chagas disease, are present across all those states, as well as in Nevada, Utah, Colorado, Wyoming, Nebraska, Illinois, Indiana, Ohio, West Virginia, Pennsylvania, Delaware, and New Jersey. Although there are currently no reported human or animal cases, individuals in these areas should still remain alert and informed for prompt response.³

Residents of Florida should exercise increased caution, as 300 kissing bugs were captured across 23 counties. The climate in the state and other Southern regions creates suitable living environments for these insects. As of this article's publication, there were no official case counts reported by other states. However, health experts warn that many individuals may be unaware they have Chagas disease, meaning accurate case numbers may be underreported. ⁴

What is Chagas disease?

Chagas disease is an infection caused by the parasite Trypanosoma cruzi (T cruzi), which is primarily found in rural areas of Mexico and Central and South America. Kissing bugs, members of the Triatominae subfamily, carry and spread the parasite by passing it to humans or animals through contact with their feces. Following a bite, kissing bugs will leave behind waste, which individuals can unknowingly rub into their eyes, nose, mouth, or other orifices where the parasite can enter the body.⁵

The infection comes in 2 phases: acute, characterized by mild symptoms that present within the first weeks or months of infection; and chronic, which affects nearly 20% to 30% of individuals who contract Chagas disease. Acute infections of Chagas disease can be identified through the presence of fever, fatigue, body aches, headaches, rash, loss of appetite, diarrhea, and vomiting. However, a hallmark symptom is Romaña's sign, or eyelid swelling. This can happen when the parasite enters the eyelid following rubbing the insect waste into the eye.⁵

Chronic infections can lead to serious adverse health outcomes and may pose a significant risk of worsening existing disease for patients with related complications. Prolonged, consistent Chagas infection can cause heart issues, such as inflammation, heart failure, altered heart rate or rhythm, stroke, or sudden death. It can also affect the gastrointestinal tract, leading to an enlarged esophagus or colon, resulting in difficulties eating or using the bathroom. These serious long-term outcomes highlight the critical need for early diagnosis and prompt treatment.⁵

Chagas disease can also spread in other ways. Notably, pregnant women can pass the infection to their babies. Health experts report that breastfeeding is still safe for mothers with Chagas infection; however, if a mother has a cracked nipple or open bleeding, they should pump and dispose of any milk until the bleeding stops. Blood transfusions and organ transplants may also lead to Chagas disease if the donated blood or organ is infected.⁵

How is Chagas disease diagnosed?

Chagas disease can only be diagnosed by health care professionals through blood or serum tests. For acute infections, blood samples are assessed using microscopy to identify trypomastigotes. However, this method is not suitable for chronic infections, as parasite levels in the blood decrease rapidly within a few months.⁶

For chronic infections, health care experts rely on detecting antibodies against the parasite using serologic tests. As of 2025, there is no test sufficiently sensitive and specific for diagnosis, and multiple tests—namely, techniques including enzyme-linked immunosorbent assay and immunofluorescent antibody test—are required to detect antibodies to different antigens.⁶

Photo of blood sample to test for Chagas disease | Image Credit: © Saiful52 - stock.adobe.com

How is Chagas disease treated?

Early diagnosis and prompt treatment are crucial for Chagas disease. Those who should seek medical attention include those with the disease, babies born with the infection, immunocompromised individuals, and those with chronic Chagas disease.⁵

Antiparasitics and symptomatic treatment are the standard treatment approaches for Chagas disease to help kill the parasite and manage associated symptoms. Antiparasitic medications can be started at any stage of the infection but are most successful when started early.⁵

The FDA has 2 approved agents that are used to treat Chagas disease. They include benznidazole for children aged 2 to 12 years and nifurtimox (Lampit; Bayer HealthCare Pharmaceuticals) for children from birth to younger than 18 years. These agents are both commercially available, and nifurtimox, in particular, can be purchased from drug wholesalers by pharmacies.⁵

What role do pharmacists play?

Pharmacists are critical health professionals and experts on the front lines, offering accessible, expedited care directly to communities. Being informed of potential or growing public health risks is critical to providing effective guidance for affected patients. Pharmacists can not only educate patients about risks of parasites, such as those that cause Chagas disease, but also help identify whether an unidentified bug bite warrants more attention or concern.

Pharmacists can also guide patients through their treatment regimen, which could include multiple agents to treat the parasite and manage symptoms. They can help identify any potential drug-drug interactions and help guide patients through their treatment plans—increasing the likelihood of adherence and optimal outcomes.

As Chagas disease becomes a growing concern in the US, awareness and early intervention remain essential. Although the infection has historically been linked to regions outside the country, rising reports underscore the need for vigilance among health professionals and communities.

REFERENCES

1. Beatty N, Hamer G, Moreno-Peniche B, et al. Chagas disease, an endemic disease in the United States. Emerging Infectious Diseases. September 2025. doi:10.3201/eid3109.241700

2. Rust A. Chagas disease, long considered only a threat abroad, is established in California and the Southern U.S. LA Times. September 1, 2025. Accessed September 8, 2025. https://www.latimes.com/science/story/2025-09-01/chagas-disease-the-deadly-disease-youve-never-heard-of-but-is-here

3. Laws J. Map shows states with Chagas disease amid call for action. Newsweek. September 3, 2025. Accessed September 8, 2025. https://www.newsweek.com/map-shows-states-chagas-disease-amid-call-action-2122985

4. Van Beusekom M. Chagas disease–carrying kissing bugs establish new base in Florida homes. CIDRAP. July 9, 2025. Accessed September 8, 2025. https://www.cidrap.umn.edu/chagas-disease/chagas-disease-carrying-kissing-bugs-establish-new-base-florida-homes

5. About Chagas disease. CDC. September 4, 2024. Accessed September 8, 2025. https://www.cdc.gov/chagas/about/index.html

6. Clinical testing and diagnosis for Chagas disease. CDC. February 9, 2024. Accessed September 8, 2025. https://www.cdc.gov/chagas/hcp/diagnosis-testing/index.html#:~:text=Diagnostic%20Procedures:%20Blood%20Specimens,immunofluorescent%20antibody%20test%20(IFA)