Conenose bugs, also called kissing bugs, are vectors of Chaga's disease although cases are few and rarely reported in the United States. The disease is more common in southern Mexico, Central American and South American countries.

A study is asking the Centers for Disease Control to declare Chagas disease, also known as "kissing bug" disease, an endemic after cases have been reported in eight different states.

Since 2013, "kissing bugs" have been reported in 31 states. In eight of these states, humans were reported to have locally-contracted Chagas disease, according to the study, which was published in September on the CDC's website and in PubMed.

Chagas disease is caused by the parasite Trypanosoma cruzi, according to the CDC. It is an endemic in 21 other countries in the Americas, excluding the U.S., and is most common in rural areas of Mexico, Central America and South America.

Trypanosoma cruzi is carried by triatomine bugs, also known as "kissing bugs," which feed on the blood of humans and animals, according to Texas A&M University. Around 55% of triatomine bugs carry the parasite.

While Chagas disease hasn't been declared endemic in the U.S., the study suggests it should be as more evidence points to the parasite's presence in the country.

"Several triatomine species are common in the southern United States, where they transmit T. cruzi and invade human dwellings," the study says.

See the states where Chagas disease has been reported in humans and animals – and what else to know as cases emerge.

Human cases of Chagas disease reported in 8 states. See map.

Of the 31 states where the bugs have been found over the past decade, humans were reported to have locally contracted Chagas disease in eight states, Sarah Hamer, a Texas A&M Veterinary Integrative Biosciences professor, previously told USA TODAY. That means humans contracted the disease domestically rather than through international travel.

Human cases of "kissing bug" disease have been reported in the following states, according to the study:

  • California
  • Texas
  • Arizona
  • Lousiana
  • Mississippi
  • Arkansas
  • Missouri
  • Tennessee

There is no federal data on the number of Chagas cases in the United States because the disease is not a nationally notifiable disease, meaning healthcare providers are not required to report cases to local and state health departments.

Animals, 'especially dogs,' commonly infected. See map.

Wildlife, captive animals and domesticated animals are likely to be infected by the parasite, according to the study. But dogs especially contract the disease.

In the U.S., 16 states have reported cases of animals contracting Chagas disease, according to the study, including:

  • Alabama
  • Arizona
  • California
  • Florida
  • Georgia
  • Kansas
  • Kentucky
  • Louisiana
  • Maryland
  • Mississippi
  • Missouri
  • New Mexico
  • North Carolina
  • Oklahoma
  • South Carolina
  • Tennesee
  • Texas
  • Virginia

What is Chagas disease?

Chagas disease symptoms include swollen eyelids, fever, diarrhea and loss of appetite. In more serious cases, infected people may experience digestive problems such as an enlarged esophagus or colon, an enlarged heart or even sudden death, according to the CDC.

"Early diagnosis and treatment can be lifesaving," the CDC states.

What are the symptoms of Chagas disease?

Chagas disease has two stages. The first stage, the acute phase, happens shortly after the infection, and the second stage, the chronic phase, occurs over a longer period of time.

The acute phase usually occurs within the first few weeks or months of infection. The CDC outlines these common symptoms:

  • Fever
  • Feeling tired
  • Body aches
  • Headache
  • Rash
  • Loss of appetite
  • Diarrhea
  • Vomiting

Another common symptom of Chagas disease during the acute phase is Romaña's sign, when an eyelid swells, according to the CDC. It occurs when the parasite gets into the eyelid, usually when an infected host rubs the triatomine's fecal matter into their eye by accident.

The chronic phase of the disease may last many years or even a lifetime, the CDC says. These more serious symptoms include:

  • Heart problems, such as an enlarged heart, heart failure, altered heart rate or rhythm, or sudden death.
  • Digestive problems, such as an enlarged esophagus or colon, can lead to trouble eating or going to the bathroom.

According to the CDC, about 20% to 30% of people infected with Chagas disease experience serious symptoms.

What are 'kissing bugs'?

Triatomines, or "kissing bugs," are nocturnal bugs that feed on blood, according to Texas A&M University's Kissing Bug Community Science program. The bugs can feed on people, domestic animals and wildlife. They feed multiple times over their lives and take several minutes to take in a full meal, the program's website states. Unlike ticks, kissing bugs do not attach to a host.

They are native to North America, Central America and South America. Eleven types of kissing bugs can be found in the United States.

Adult kissing bugs grow to be about half an inch to an inch long. They hatch small eggs and can live up to two years, according to the program's website.

Contributing: Carlie Procell

Julia is a Trending reporter for USA TODAY and covers all things Labubu and Pop Mart, scientific studies and trending news. Connect with her on LinkedIn, X, Instagram, and TikTok: @juliamariegz, or email her at jgomez@gannett.com

Greta Cross is a national trending reporter at USA TODAY. Story idea? Email her at gcross@usatoday.com.

This article originally appeared on USA TODAY: 'Kissing bug' disease is endemic in US, researchers say. See map of reported cases.

Reporting by Julia Gomez and Greta Cross, USA TODAY / USA TODAY

USA TODAY Network via Reuters Connect