The J.M. Smucker Company said it initiated a voluntary recall and advised consumers to dispose of some potentially contaminated products.The J.M. Smucker Company has recalled several Jif peanut butter products sold in the United States and Canada because of potential salmonella contamination that federal regulators said has been tied to 14 illnesses.In a statement posted Friday on the federal Food and Drug Administration’s website, the company encouraged consumers who bought the potentially contaminated products to immediately dispose of them.The products listed include several types of creamy, crunchy, reduced-fat and natural peanut butter products in various sizes, as well as a 40-ounce jar of natural honey.The Smucker Company said it was “coordinating a thorough investigation” with the F.D.A. The recalled items were sold nationwide.Salmonella is a bacteria that can grow in foods and, when ingested, can cause fever, diarrhea, vomiting and abdominal cramps. In young children, older people or those with weakened immune systems, the infection can be more serious, and potentially fatal.The F.D.A. said salmonella cases connected to the peanut butter had been reported in a dozen states as of Sunday. Two people had been hospitalized, it said.The agency said that epidemiologic evidence indicated that Jif brand peanut butter produced at the Smucker Company facility in Lexington, Ky., was “the likely cause of illnesses in this outbreak.”The recall affects Jif brand peanut butter products with lot code numbers 1274425 through 2140425, with the digits ending with 425. The lot numbers are included alongside best-if-used-by date.Every month, the F.D.A. announces the recall of several products — some over cross-contamination with allergens, others because “foreign materials,” such as metal, have been found in food, and sometimes over bacterial contamination.In October, hundreds of people across the United States were sickened in a salmonella outbreak linked to imported red, white and yellow onions. Last summer, 31 people were sickened after eating hydroponic lettuce.

The lone star tick can trigger an allergic reaction to red meat in those bitten. Now this arachnid’s territory is expanding.One night in 2008, Deborah Fleshman awoke in her bed to find that her legs had turned beetroot red. Welts, some a foot wide, had appeared along her torso.Ms. Fleshman, a nurse at the time, had earlier that evening hosted a cookout at her home in Greenwood, Del., a town of about 1,000 people 25 miles south of Dover. She drank a couple of beers. She ate a cheeseburger.Hours later, she told her worried father, “I feel like I’m dying.”Ms. Fleshman, now 60, is among the thousands of Americans diagnosed with alpha-gal syndrome, an allergic reaction to mammal meats like pork, beef and lamb, which growing evidence shows can be triggered by a tick bite.“It feels like you’re on fire, and then it feels like you slept with a cactus,” she said. “The itching is unbearable.”Researchers have traced the syndrome to the lone star tick, named for the signature white splotch, or “lone star,” on females’ backs. They’re historically found in the southern United States, but increasingly, these arachnids are being spotted in parts of the Midwest and the Northeast.The tick’s territory is expanding, thanks in part to global warming, say scientists. With more hot days each year, the ticks, which thrive in warm and humid conditions, have more time to feed on their hosts and reproduce. At the same time, alpha-gal diagnoses appear to be rising.“What we’re now seeing is a wide open door for ticks to continue expanding their range further northward; bringing more people into the fold of the arthropod-borne diseases,” said Michael Raupp, a professor emeritus in entomology at the University of Maryland.The Centers for Disease Control and Prevention estimates that between 2004 and 2019, the total number of tick-borne diseases in the United States more than doubled. In the meantime, other devastating pests that were previously constrained by cooler temperatures — like the dengue virus-carrying tiger mosquito, or the cabbage-munching harlequin bug — have also marched forth beyond their historic ranges.“We’re venturing into uncharted waters in so many dimensions with climate change,” Dr. Raupp said.By nature, ticks are travelers; they attach themselves to hosts in order to suck their blood, hitching a ride in the process. Scientists say an explosion in the population of the white-tailed deer, their primary host, has also helped them to spread.According to some maps, the lone star tick has advanced as far west as parts of Nebraska, and as far northeast as Maine. Climatic conditions are also suitable for the ticks to establish populations along the coast of Washington, Oregon and California, other models indicate.Scientists first began noticing an allergic reaction to alpha-gal in 2006, but it was not until several years later that they understood it was likely caused by the bite of the lone star tick. By 2012, it had already been found in 39 states, according to one study.“The spatial distribution of the species has definitely increased by at least 30 to 50 percent in the last half a century,” said Ram Raghavan, an assistant professor in epidemiology and disease ecology at the University of Missouri, who has mapped the lone star tick’s spread. According to his research, the ticks are expected to continue to shift and expand their range; both to the north and west.Goudarz Molaei, the director of a state-run tick and pathogen surveillance program in Connecticut, said that the lone star tick has firmly established itself in at least two counties in the state. “Because of climate change, what lands in our region, stays,” he said.The lone star tick bite can result in several other illnesses, including the recently identified Heartland virus disease and Bourbon virus disease, both of which can lead to fever, fatigue and in some cases hospitalization, and even death. Unlike the blacklegged tick, it cannot transmit Lyme disease, though one study indicates that the blacklegged tick may also be implicated in spreading alpha-gal.Alpha-gal syndrome is triggered by a complex sugar called galactose-alpha-1, 3-galactose, or alpha-gal, for short. The sugar is found in most mammals, but not in fish, reptiles, birds or humans. When the lone star tick feeds, alpha-gal is spread through its saliva, exposing the host’s immune system to the sugar. For some people, this triggers an overactive immune response the next time they encounter it.More than 34,000 people in the United States have tested positive for alpha-gal syndrome, according to a 2021 paper. A map publicly generated by individuals who say they suffer from the condition indicates that the syndrome may have spread as far as Washington and Hawaii, though this does not mean the sufferers were bitten by ticks in those states.Though the conditions present mildly for some, others suffer hives, swelling, wheezing, diarrhea or even anaphylaxis, which can be fatal. Unlike many other allergic conditions, the symptoms may take several hours to appear after consuming meat products, making the syndrome difficult to diagnose.“It’s never predictable,” said Jennifer Platt, an adjunct professor in public health at the University of North Carolina at Chapel Hill and a co-founder of the nonprofit Tick-Borne Conditions United. “I know people that spend the night in the emergency room parking lot, waiting for a reaction,” she said, adding, “I think of alpha-gal syndrome as Lyme 2.0.”“There are so many parallels in terms of patients being told by their providers that it’s all in their head,” Dr. Platt said.Even after treatment, some symptoms of Lyme disease, including pain and fatigue, can linger for months, according to the C.D.C. But some medical experts remain skeptical of this chronic version of the disease, disagreeing about its presentation, diagnosis and treatment.Some sufferers of alpha-gal — especially in states where the ticks have been thought to be less common — described the frustration of seeking a diagnosis and encountering disbelief from medical professionals.In Ms. Fleshman’s case, it took more than seven years and about a dozen trips to the emergency room before she finally found out what was wrong. At one point, an infectious disease doctor told her she could not have alpha-gal syndrome, because there were no lone star ticks in the state of Delaware.“I was livid,” Ms. Fleshman said. “Do you really think they read a sign that says, ‘Do Not Enter,’ and they listen?”

As Buruli ulcer cases have risen, they have taken a physical and psychological toll but also offered hope that scientists can solve the bacteria’s many mysteries.SORRENTO, Australia — To Rob Courtney, it looked like a sunburn. But after a few days, the redness and inflammation got worse. Soon, the skin on his right foot was split open, the wound oozing. His doctor sent him straight to the emergency room.Then came the horrifying diagnosis: Mr. Courtney was infected with a species of flesh-eating bacteria.In recent years, cases of the disease, known as Buruli ulcer, have exploded in the seaside area where Mr. Courtney, 80, lives in southeastern Australia.As he would learn, it is a fearsome intruder.The ulcer left the flesh on his foot corroded and gangrenous. It devoured a skin graft. Eventually, doctors prescribed the same powerful antibiotics used to treat leprosy and tuberculosis. The drugs made him feel nauseated and fatigued, and turned his sweat and tears orange. He spent nearly 50 days in the hospital.“It’s been a bit of a journey,” Mr. Courtney said recently as he lay on an examination table at his local clinic, where he has endured a daily wound dressing for several weeks. “I wouldn’t recommend it.”Buruli ulcer has been reported in 33 countries, primarily in Africa, where a lack of access to health care can mean that cases go on for months, sometimes resulting in disfigurement and disability.In Australia, where cases of the ulcer have been recorded since the 1940s, the recent increase in infections has brought new attention to the neglected disease. That, along with a growing global interest in infectious diseases, has raised hopes that scientists might finally have the resources to crack its code.The area hit hardest in Australia is the Mornington Peninsula, in the state of Victoria. More than 180 cases per year have been reported in the state since 2016, peaking in 2018 at 340. In February, the disease crept further into the suburbs of Melbourne, a city of five million people.No one knows exactly how the infection spreads or why it has flared on the Mornington Peninsula, an affluent region less than 50 miles from Melbourne where cafes line leafy boulevards and thousands of tourists visit each year.The small town of Blairgowrie on the Mornington Peninsula. No one knows exactly how the infection spreads or why it has flared in the region.Christina Simons for The New York TimesScientists think that Buruli ulcer — and up to 75 percent of emerging diseases, including the coronavirus — is zoonotic, meaning it jumps from animals to humans. They say zoonotic disease are becoming more common in part because of human encroachment on wild environments.As for the spike in cases in Victoria, the leading theory is that possums, a marsupial native to Australia, carry the bacteria, which are then transmitted to humans by mosquitoes that have come into contact with the animal’s feces.The bacterium has long been present, but “what we’ve done is stumbled into it and maybe helped it to amplify and become the unwitting victims,” said Dr. Paul Johnson, a physician and professor of infectious diseases at Austin Health in Melbourne. “We’ve provided situations where it can expand rapidly and cause human disease.”In recent years, as attention to the disease has increased funding for research, Dr. Johnson and others have been trying to figure out exactly how Buruli ulcer is transmitted. To test their theory, the scientists are working to reduce the number of mosquitoes on the Mornington Peninsula to see whether cases of Buruli ulcer drop as well.On a Saturday in late February, Dr. Johnson and Tim Stinear, a professor of microbiology at the Doherty Institute at the University of Melbourne, led a troop of more than a dozen researchers — clad in yellow “Beating Buruli in Victoria” vests — as they set mosquito traps in the suburbs of the Mornington Peninsula.The researchers have also been on the hunt for possum feces, which they say has given them a crucial map of hot spots where the bacteria are present. “Once you start looking for this stuff, you see it everywhere,” Professor Stinear said as he knelt in a driveway, using a stick to scoop the scat into a sandwich bag. “Because it is everywhere.”Tim Stinear and Stacey Lynch, who are studying how Buruli ulcer is transmitted, preparing mosquito traps in the Mornington Peninsula last month.Christina Simons for The New York TimesDespite possums’ ubiquitousness, they are protected as native creatures in Australia. That has tended to stall research and has stood in the way of culling programs that could reduce the spread of the disease. (Vaccinating the animals, though, is a possibility.) Efforts to cull mosquitoes with insecticide have also met pushback from environmentalists.The opposition is hardly a surprise, researchers say, given the global wave of distrust in science. But funding work on obscure diseases like Buruli ulcer is crucial to halting future outbreaks. “We never know when they will become important,” Professor Stinear said. “This is a lesson that we learned with coronavirus.”For those who contract Buruli ulcer, the journey can be arduous, leading to severe illness and sometimes even amputation and death in older and vulnerable patients. The wounds can take months to heal, scarring patients both physically and psychologically.“It’s a huge illness to deal with,” said Dr. Daniel O’Brien, an infectious disease specialist based in Geelong, 50 miles southwest of Melbourne. “It becomes quite disconcerting for people in the community.”Michael Steele, a Buruli ulcer patient, was waiting for a skin graft this month. He said he believed he contracted the disease in Sorrento last year.Christina Simons for The New York TimesOn a Friday in March, Dr. O’Brien, masked and bespectacled, treated Mr. Courtney and more than a dozen other patients at a clinic in Sorrento on the Mornington Peninsula. When Dr. O’Brien began traveling there about a decade ago, he would see a handful of patients each week. Now he sees up to 50.He has treated more than a thousand patients, both in Australia and overseas, for the disease. Many of those in Australia are older, but others are young teachers, laborers and even children.He measures their lesions gently with a ruler, marking them to track their progression. Though they look like the stuff of nightmares — some have ulcers that eat all the way to the bone — most patients describe them as painless. The flesh-eating toxin produced by the bacteria presents a peculiar horror: It both weakens the immune response and numbs the flesh it is consuming. It’s “quite an extraordinary organism, really,” Dr. O’Brien said of the bacterium, “and a formidable foe.”In Mr. Courtney’s case, the ulcer had ravaged the top half of his foot before doctors could give a diagnosis. They have since performed surgeries to remove the necrotic, concrete-like tissue. “Unless you get rid of that dead flesh, the skin will never heal,” said Dr. Adrian Murrie, a physician at the clinic who has been treating Mr. Courtney.Other patients with less severe cases sometimes decline treatment, instead opting for natural remedies like applying heat and clay. Though the body can occasionally fight off smaller ulcers, such treatments can pose a real danger in serious cases, Dr. O’Brien said.In most cases, the course of treatment is antibiotics. Previously, the disease was largely treated with surgery, but with better medications, the prognosis has vastly improved in recent years. “It was thought the antibiotics didn’t work,” Dr. O’Brien said. “Because it actually gets worse before it gets better.”Still, for now, prevention is close to impossible.“We don’t know how to stop it,” he said. But if the answer is to be found anywhere, he said, it’s in Australia.For Mr. Courtney, his battle with the disease is far from over. Doctors expect his treatment to last at least another six months.“When you’re 80 years old, and you lose a year,” he said, “you get really savage about it.”A mosquito trap left by the researchers.Christina Simons for The New York Times