The number of infant botulism cases tied to baby formula has climbed to 15. Here's what to know

An outbreak of botulism tied to ByHeart baby formula has made at least 15 infants sick in 12 states, a California health official said Monday.

Nine cases of infant botulism type A have been confirmed, with results on six others pending, said Dr. Erica Pan, health officer for the California Department of Public Health. That's an increase from 13 cases in 10 states reported on Saturday.

Federal and state officials are investigating the outbreak, which began in mid-August. No deaths have been reported.

ByHeart, a maker of organic baby formula based in New York, recalled two lots of its Whole Nutrition Infant Formula over the weekend.

“Consumers in possession of this product should stop using it immediately,” California officials said.

Here’s what to know about the outbreak and infant botulism.

The outbreak has sickened babies aged 2 weeks to 5 months since mid-August. The infants were hospitalized after consuming ByHeart powdered formula, according to the U.S. Centers for Disease Control and Prevention.

ByHeart officials agreed to recall two lots of the company's Whole Nutrition Infant Formula, according to the U.S. Food and Drug Administration. They include lots 206VABP/251261P2 and 206VABP/251131P2, with best-by dates of December 2026.

California officials confirmed that a sample from an open can of ByHeart baby formula fed to an infant who fell ill contained the type of bacteria that causes the toxin linked to the outbreak. The tests to confirm contamination involve injecting mice with the cultured bacterium and then waiting up to four days to see if they get sick.

“These mice got sick really quickly,” Pan said in an interview.

ByHeart officials called for testing of unopened cans of formula from the recalled batches.

“Testing unopened cans will provide reliable evidence that will help bring clarity to families who are understandably concerned,” the company said in a statement Monday.

At least 84 babies in the U.S. have been treated for botulism since August, California officials said. That includes those confirmed to have been fed ByHeart formula.

The FDA is investigating whether any of the others are also linked to the same baby formula.

Infant botulism typically affects fewer than 200 babies in the U.S. each year. It is caused by a type of bacteria that produces a toxin in the large intestine. The bacterium is spread through hardy spores present in the environment that can cause serious illness, including paralysis.

Infants younger than 1 are particularly vulnerable to infection because their gut microbiomes are not developed enough to prevent the spores from germinating and producing the toxin. They can be sickened after exposure to the spores in dust, dirt or water or by eating contaminated honey.

Symptoms can take weeks to develop and can include poor feeding, loss of head control, drooping eyelids and a flat facial expression. Babies may feel “floppy” and can have problems swallowing or breathing.

No known outbreaks of infant botulism tied to powdered formula have previously been confirmed, said Dr. Steven Abrams, a University of Texas nutrition expert.

“This would be extremely rare,” he said.

The only treatment is known as BabyBIG, an IV medication made from the pooled blood plasma of adults immunized against botulism. California's Infant Botulism Treatment and Prevention Program developed the product and is the sole source worldwide.

BabyBIG works to shorten hospital stays and decrease the severity of illness in babies with botulism. Because the infection can affect the ability to breathe, infants often need to be placed on ventilators.

All of the children in the ByHeart outbreak have received the medication, the CDC said. The treatment is delivered in vials that cost $69,300 apiece, Pan said.

There is little danger of infant formula shortages because of this outbreak. ByHeart, which was founded in 2016, accounts for an estimated 1% of national formula sales, according to the CDC. The company sells formula through its website and in retail stores nationwide.

That's far different from the crises in late 2021 and 2022, when four infants were sickened by a different germ after consuming formula made by Abbott Nutrition. Two of the babies died. No direct link was found between the Abbott products and the infections caused by cronobacter sakazakii, but FDA officials closed the company's Michigan plant after contamination and other problems were detected.

Abbott recalled top brands of infant formula, triggering a massive nationwide shortage that lasted months.

In 2022, ByHeart recalled five batches of infant formula after a sample at the company's packaging plant tested positive for cronobacter sakazakii, the germ at the heart of the Abbott crisis. In 2023, the FDA sent a warning letter to the company detailing “areas that still require corrective actions.”

Federal health officials have vowed to overhaul the U.S. food supply and are taking a new look at infant formula.

Health Secretary Robert F. Kennedy Jr. has directed the FDA to review the nutrients and other ingredients in infant formula, which fills the bottles of millions of American babies.

The effort, dubbed “Operation Stork Speed,” is the first deep look at the ingredients since 1998.

FDA officials are reviewing comments from industry, health experts and public to decide next steps.

The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Department of Science Education and the Robert Wood Johnson Foundation. The AP is solely responsible for all content.

Stephen Dexter holds a container of ByHeart baby formula, which was recently recalled by ByHeart, in Flagstaff, Ariz., on Wednesday, Nov. 12, 2025. (AP Photo/Cheyanne Mumphrey)

A sign for ByHeart, a manufacturer of organic baby formula, is displayed outside a building that houses a plant for the company on Tuesday, Nov. 11, 2025, in Portland, Ore. (AP Photo/Jenny Kane)

This undated image provided by ByHeart shows ByHeart formula products.(ByHeart via AP)

FILE - The Food and Drug Administration seal is seen at the Hubert Humphrey Building Auditorium in Washington, April 22, 2025. (AP Photo/Jose Luis Magana, File)

DUBAI, United Arab Emirates (AP) — Iran kept up its attacks on Persian Gulf neighbors on Wednesday as airstrikes pounded Tehran, while U.S. President Donald Trump again made contradictory statements about whether he was ready to wind down the war or escalate it.

Trump struck a hard line Wednesday in a Truth Social post, demanding that Iran stop blocking the Strait of Hormuz — the waterway vital to global oil supplies — or the U.S. would bomb the Islamic Republic “back to the Stone Ages.” A day earlier, Trump said the U.S. “will not have anything to do with” ensuring the security of ships passing through Hormuz; that was an apparent backtrack from an earlier threat to attack Iran's power grid and other infrastructure if it didn't open the strait by April 6.

Trump, who is scheduled to give a televised address Wednesday evening, said Tuesday he could walk away from the war in two to three weeks once he felt confident Iran would not be able to build a nuclear weapon — even if Tehran does not agree to a ceasefire.

But his latest Truth Social post struck a more belligerent tone as more American troops move into the region for a possible ground offensive after weeks of airstrikes targeting Iran.

Trump also claimed Wednesday that “Iran's New Regime President” wanted a ceasefire. It wasn't clear to whom the U.S. president was referring since Iran still has the same president. Iran’s Foreign Ministry spokesman, Esmail Baghaei, called Trump's claim “false and baseless,” according to a report on Iranian state television.

Speaking earlier to Al Jazeera, Iranian Foreign Minister Abbas Araghchi signaled Tehran’s willingness to keep fighting. “You cannot speak to the people of Iran in the language of threats and deadlines,” he said. “We do not set any deadline for defending ourselves.”

Since the war began on Feb. 28, Trump has offered shifting objectives and repeatedly has said it could be over soon while also threatening to widen the conflict. Thousands of additional U.S. troops are currently heading to the Middle East, and speculation abounds about the purpose of their deployment.

Just days ago, Trump threatened to attack Iran’s Kharg Island oil export hub. And there has also been speculation about whether the U.S. could decide to send in military forces to secure Iran’s uranium stockpile — a complex and risky operation, fraught with radiation and chemical dangers, according to experts and former government officials.

Adding to the confusion is what role Israel - which has been bombing Iran alongside the U.S. — might play in any of these scenarios.

Trump has been under growing pressure to end the war as oil prices have skyrocketed, pushing up the cost of gasoline, food and other goods. The spot price of Brent crude, the international standard, was up more than 40% since the start of the war, trading at more than $103 a barrel on Wednesday.

A fifth of the world’s traded oil passes through the strait in peacetime, and even if it were to reopen quickly, some effects like higher food prices could persist for months or longer.

The U.S. has presented Iran with a 15-point plan aimed at bringing about a ceasefire, including a demand for the strait to be reopened and for its nuclear program to be rolled back.

Iran insists its nuclear program is peaceful. Its own five-point response includes retaining sovereignty over the strait.

In the interview with Al Jazeera, Araghchi acknowledged receiving direct messages from U.S. Mideast envoy Steve Witkoff. He insisted, however, that there were no direct negotiations and said Iran has no faith that talks with the U.S. could yield any results, saying “the trust level is at zero.”

He warned against any U.S. attempt to launch a ground offensive, saying “we are waiting for them.”

A cruise missile slammed into an oil tanker off Qatar’s coast Wednesday, the Defense Ministry said. The 21-member crew of the tanker, contracted by state-owned QatarEnergy, was evacuated and no casualties were reported.

A fully-loaded Kuwaiti oil tanker came under attack off Dubai the day before, one of more than 20 ships attacked by Iran during the war.

In the United Arab Emirates, a person was killed when he was hit by debris from an intercepted drone in Fujairah, one of the country’s seven emirates.

Bahrain sounded two alerts for incoming missiles, while Kuwait’s state-run KUNA news agency said a drone hit a fuel tank at Kuwait International Airport, sparking a large fire.

Jordan’s military said it intercepted a ballistic missile and two drones fired from Iran in the last 24 hours. No casualties were reported. Two drones were also intercepted in Saudi Arabia, and air raid sirens sounded in Israel though there were no immediate reports of damage or casualties.

An airstrike on Tehran, meanwhile, appeared to have hit the former U.S. Embassy compound, which has been controlled by Iran’s Revolutionary Guard since American diplomats were held hostage there in 1979.

Witnesses said buildings outside the massive compound had their windows blown out and that it appears the strike happened inside the walled facility.

Israel also said it hit a plant in Iran producing fentanyl, a synthetic opioid. Israel and the United States have alleged in recent years that Iran was experimenting with using fentanyl in chemical weapons.

Iran acknowledged a strike Tuesday on Tofigh Daru factory, but insisted it only supplied “hospital drugs.” Hospitals use fentanyl to treat severe pain but it can also be fatal.

In Lebanon, at least five people were killed in an Israeli strike on a Beirut neighborhood.

Israel invaded southern Lebanon after the Iran-linked Hezbollah militant group began launching missiles into northern Israel days after the outbreak of the war. Many Lebanese fear another prolonged military occupation.

More than 1,200 people have been killed in Lebanon and more than 1 million displaced, according to authorities. Ten Israeli soldiers have also died there.

In Iran, authorities say more than 1,900 people have been killed, while 19 have been reported dead in Israel. More than two dozen people have died in Gulf states and the occupied West Bank, while 13 U.S. service members have been killed.

Rising reported from Bangkok. Associated Press writers Giovanna Dell’Orto in Miami and Samy Magdy in Cairo contributed to this report.

A young girl is comforted by her father and Israeli soldiers as they take cover in a bomb shelter during air raid sirens warning of incoming Iranian missile strikes in Bnei Brak, Israel, Wednesday, April 1, 2026. (AP Photo/Oded Balilty)

People inspect the site of an Israeli strike amid debris and damaged vehicles in Beirut, Lebanon, Wednesday, April 1, 2026. (AP Photo/Hassan Ammar)

A man feeds stray cats in Tehran, Iran, Tuesday, March 31, 2026. (AP Photo/Vahid Salemi)

The Indian flagged LPG carrier Jag Vasant transporting liquefied petroleum gas, is seen at the Mumbai Port in Mumbai, India, after it arrived clearing the Strait of Hormuz, Wednesday, April 1, 2026. (AP Photo/Rafiq Maqbool)

Firefighters and rescue workers work at the site of Israeli airstrikes, in Beirut, Lebanon, Wednesday, April 1, 2026. (AP Photo/Hussein Malla)

A firefighter extinguishes a car at the site of Israeli airstrikes, in Beirut, Lebanon, Wednesday, April 1, 2026. (AP Photo/Hussein Malla)

Israel's rescue teams and residents take shelter as sirens sounds next to a site struck by an Iranian missile in Bnei Brak, Wednesday, April 1, 2026. (AP Photo/Oded Balilty)

A police vehicle is seen through a shattered windshield at the site of an Israeli strike in Beirut, Lebanon, Wednesday, April 1, 2026. (AP Photo/Hassan Ammar)

Two men ride scooters past charred debris at the site of an Israeli strike in Beirut, Lebanon, Wednesday, April 1, 2026. (AP Photo/Hassan Ammar)