Tennessee joins nine other US states with measles outbreaks. Here's what to know

Tennessee health officials confirmed a measles outbreak on Thursday, bringing the number of U.S. states with outbreaks to 10.

Nearly a week ago, the U.S. was up to 800 cases of measles nationwide. Texas has more than 600 known cases with the outbreak in the western part of the state approaches the three-month mark.

Two unvaccinated elementary school-aged children died from measles-related illnesses in the epicenter in West Texas, and an adult in New Mexico who was not vaccinated died of a measles-related illness.

Other states with active outbreaks — defined as three or more cases — include Indiana, Kansas, Michigan, Montana, Oklahoma, Ohio, Pennsylvania and New Mexico. The U.S. has more than double the number of measles cases it saw in all of 2024.

North America has two other outbreaks. One in Ontario, Canada, has sickened 925 from mid-October through April 16. And as of Tuesday, the Mexican state of Chihuahua state has 514 measles cases, according to data from the state health ministry. The World Health Organization has said cases in Mexico are linked to the Texas outbreak.

Measles is caused by a highly contagious virus that's airborne and spreads easily when an infected person breathes, sneezes or coughs. It is preventable through vaccines, and has been considered eliminated from the U.S. since 2000.

As the virus takes hold in other U.S. communities with low vaccination rates, health experts fear the virus that the spread could stretch on for a year. Here's what else you need to know about measles in the U.S.

Texas state health officials said Tuesday there were 27 new cases of measles since Friday, bringing the total to 624 across 26 counties — most of them in West Texas. Two more Texans were hospitalized, for a total of 64 throughout the outbreak, and Bailey County logged its first two cases.

State health officials estimated about 2% of cases — fewer than 10 — are actively infectious.

Sixty-two percent of Texas' cases are in Gaines County, population 22,892, where the virus started spreading in a close-knit, undervaccinated Mennonite community. The county has had 386 cases since late January — just over 1% of the county's residents.

The April 3 death in Texas was an 8-year-old child, according to Health Secretary Robert F. Kennedy Jr. Health officials in Texas said the child did not have underlying health conditions and died of ''what the child's doctor described as measles pulmonary failure.'' A unvaccinated child with no underlying conditions died of measles in Texas in late February — Kennedy said age 6.

New Mexico announced two new cases Tuesday, bringing the state's total to 65. Six people have been hospitalized since the outbreak started. Most of the state's cases are in Lea County. Two are in Eddy County and Chaves and Doña Ana counties have one each.

How many cases are there in Kansas?

Kansas was steady this week with 37 cases in eight counties in the southwest part of the state. Finney, Ford, Grant, Gray and Morton counties have fewer than five cases each. Haskell County has the most with eight cases, Stevens County has seven, Kiowa County has six.

The state's first reported case, identified in Stevens County on March 13, is linked to the Texas outbreak based on genetic testing.

How many cases are there in Oklahoma?

Oklahoma confirmed one more case Tuesday for a total cases of 13: 10 confirmed and three probable. The first two probable cases were ''associated'' with the West Texas and New Mexico outbreaks, the state health department said.

How many cases are there in Ohio?

The Ohio Department of Health confirmed 32 measles cases in the state Thursday. The state count includes only Ohio residents. There are 16 cases in Ashtabula County near Cleveland, 14 in Knox County and one each in Allen and Holmes counties.

Health officials in Knox County, in east-central Ohio, said there are a total of 20 people with measles, but seven of them do not live in the state.

How many cases are there in Indiana?

Indiana confirmed two more cases Monday in an outbreak that has sickened eight in Allen County in the northeast part of the state — five are unvaccinated minors and three are adults whose vaccination status is unknown. The cases have no known link to other outbreaks, the Allen County Department of Health said Monday.

In far northwest Pennsylvania, Erie County health officials declared a measles outbreak April 14 after finding two new cases linked to a measles case confirmed March 30. The state has had nine cases overall this year, six of which are not linked to the outbreak, including international travel-related cases in Montgomery County and one in Philadelphia.

How many cases are there in Michigan?

Montcalm County, near Grand Rapids in western Michigan, has four linked measles cases. State health officials say the cases are tied to Canada's large outbreak in Ontario. The state has eight confirmed measles cases as of Monday, but the remaining four are not part of the Montcalm County outbreak.

How many cases are there in Montana?

Montana state health officials announced five cases Thursday in unvaccinated children and adults who had traveled out of state, and confirmed it was an outbreak on Monday. All five are isolating at home in Gallatin County in the southwest part of the state.

How many cases are there in Tennessee?

Tennessee has six measles cases as of Thursday. Health department spokesman Bill Christian said all cases are the middle part of the state, and that ''at least three of these cases are linked to each other'' but declined to specify further. The state also did not say whether the cases were linked to other outbreaks or when Tennessee's outbreak started.

The state health department announced the state's first measles case March 21, three more on April 1 and the last two on April 17, but none of the news releases declared an outbreak. Tennessee is on a list of outbreak states in a Thursday CDC report.

Where else is measles showing up in the U.

S.?

Cases and outbreaks in the U.S. are frequently traced to someone who caught the disease abroad. In 2019, the U.S. saw 1,274 cases and almost lost its status of having eliminated measles.

What do you need to know about the MMR vaccine?

The best way to avoid measles is to get the measles, mumps and rubella vaccine. The first shot is recommended for children between 12 and 15 months old and the second between 4 and 6 years old.

Getting another MMR shot is harmless if there are concerns about waning immunity, the CDC says. People who have documentation of receiving a live measles vaccine in the 1960s don't need to be revaccinated, but people who were immunized before 1968 with an ineffective measles vaccine made from ''killed'' virus should be revaccinated with at least one dose, the agency said.

People who have documentation that they had measles are immune and those born before 1957 generally don't need the shots because most children back then had measles and now have ''presumptive immunity.''

But childhood vaccination rates have declined nationwide since the pandemic and more parents are claiming religious or personal conscience waivers to exempt their kids from required shots. The U.S. saw a rise in measles cases in 2024, including an outbreak in Chicago that sickened more than 60.

What are the symptoms of measles?

Measles first infects the respiratory tract, then spreads throughout the body, causing a high fever, runny nose, cough, red, watery eyes and a rash.

The rash generally appears three to five days after the first symptoms, beginning as flat red spots on the face and then spreading downward to the neck, trunk, arms, legs and feet. When the rash appears, the fever may spike over 104 degrees Fahrenheit, according to the CDC.

Most kids will recover from measles, but infection can lead to dangerous complications such as pneumonia, blindness, brain swelling and death.

There's no specific treatment for measles, so doctors generally try to alleviate symptoms, prevent complications and keep patients comfortable.

___

AP Science Writer Laura Ungar contributed to this report.

___