An outbreak of parasitic illness linked to iceberg lettuce is affecting nine U.S. states, federal health officials have announced. That's up from the five affected states that were identified in earlier stages of the officials' investigation.

This lettuce-related outbreak is one of several in the U.S. that are being caused by the parasite Cyclospora cayetanensis, which can enter the body when someone consumes food or water contaminated with the organism. The federal government has not officially identified a source of contamination in the other Cyclospora outbreaks yet, although some state officials have mentioned potential culprits. (North Carolina officials have pointed to cilantro and parsley, for example.)

The nine-state outbreak linked to iceberg lettuce includes cases in Illinois, Indiana, Kansas, Kentucky, Michigan, Ohio, Oklahoma, Pennsylvania and West Virginia, according to the Food and Drug Administration (FDA). To date, 1,947 people have been infected across these states and reported eating Taco Bell before they got sick. There have been 98 hospitalizations and no deaths.

Data collected by federal officials had previously pointed to shredded lettuce served at Taco Bell as a common source of exposure, and from there, they identified the supplier as Taylor Farms de Mexico. "Taco Bell has indicated they are no longer using lettuce from Taylor Farms de Mexico as of July 17, 2026," the FDA noted.

Specifically, the infections have been linked to lettuce sourced from central Mexico, prompting Taylor Farms to remove all of its iceberg lettuce from that region from the U.S. market. The company has also issued a recall. A complete list of recalled products can be found on the FDA's website.

The recall affects products that were distributed in the nine states listed above, as well as additional states, all of which are listed on the FDA's website. Consumers, restaurants and retailers that purchased or received recalled lettuce are advised to discard it immediately and not consume it.

"We also expect to continue to see the number of confirmed cases rise, despite the recall, due to the fact that it can take as long as six weeks for CDC [Centers for Disease Control and Prevention] and state officials to determine if a sick person is part of this outbreak," the FDA's latest update notes. "FDA will continue to work with federal and state partners to investigate this multistate outbreak and ensure products implicated in this outbreak have been removed from the market."

This article is for informational purposes only and is not meant to offer medical advice.

U.S. health officials have identified shredded iceberg lettuce served at Taco Bell as one source of contamination behind an outbreak of parasitic infections affecting over 1,000 people.

The outbreak has been caused by the protozoan parasite Cyclospora cayetanensis, which can enter the body when someone consumes food or water contaminated with the parasite. Since May 1, there have been 1,644 confirmed cases across Indiana, Kentucky, Ohio, West Virginia and Michigan, which is currently the hardest-hit state.

(Health officials are also investigating additional cases of Cyclospora infection in the U.S. that have yet to be linked to this specific lettuce-related outbreak. Those other potential cases remain under investigation and total over 5,100, per the Centers of Disease Control and Prevention (CDC).)

In the five-state outbreak, there have been 94 hospitalizations and no deaths to date.

Through an investigation, health officials found that all 1,644 of the sickened people with confirmed cases of Cyclospora reported eating Taco Bell in Indiana, Kentucky, Michigan, Ohio or West Virginia before becoming ill. Interviews with the affected individuals suggested that shredded lettuce might be a common source of exposure.

The Food and Drug Administration (FDA) then investigated the source of the lettuce, identifying a single supplier of iceberg lettuce from Mexico that was used by Taco Bell locations where the people ate before becoming ill. News reports have named California-based Taylor Farms as the supplier.

"FDA is working directly with the identified supplier to determine if potentially contaminated shredded iceberg lettuce remains on the market," an FDA notice states. "As part of this investigation, FDA and state partners have initiated collection of product samples for testing and analysis."

The investigation is ongoing, and additional sources of contamination or affected restaurants could possibly be identified later, the FDA noted. In the meantime, Taco Bell has said it will stop using lettuce from the implicated supplier.

"Taco Bell is working to stop use of all lettuce implicated by this investigation. Not all Taco Bell locations in these states received implicated product," the FDA statement says.

Currently, the CDC is warning consumers not to eat shredded iceberg lettuce served at Taco Bell locations in Indiana, Kentucky, Michigan, Ohio or West Virginia.

Case counts reported by individual states may differ from the FDA's and CDC's counts, because states may include both probable and confirmed cases. The FDA and CDC will update their totals once they can confirm additional cases reported to them.

Symptoms of Cyclospora infection typically emerge two to 14 days after a person consumes the parasite. These symptoms include watery diarrhea, fatigue, cramping, bloating, gas and loss of appetite, and without treatment, they can last between a few days to a month or more. The infection is treated with an antibiotic, which blocks the parasite's ability to multiply.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: An 83-year-old man in Belgium

The symptoms: The man sought medical attention at a hospital because the muscles on one side of his face had weakened suddenly, causing it to droop — a condition called unilateral peripheral facial-nerve palsy. He had also recently had a fever, which had since resolved.

Tests run by the neurology department found the man had anemia, fatty liver disease and an enlarged spleen. Combined with his recent fever, these findings led the team to assume he had a viral infection. However, he tested negative for a variety of germs, including Epstein-Barr virus, which causes mono; cytomegalovirus; human immunodeficiency virus (HIV); and hepatitis A, B, C, and E.

The man's liver abnormalities hadn't resolved by one week later, but his facial-nerve palsy cleared following a 10-day course of a strong corticosteroid. But then, over the next month, the man's knees and ankles became stiff and painful, and his legs and feet — and occasionally his face, arms and hands — began to swell. He reported feeling generally unwell, he had gained 11 pounds (5 kilograms), and his urine had darkened even though he had been drinking more water than usual. All of these signs pointed to problems with his kidney function.

Besides the conditions uncovered on his recent medical examinations, the patient had long-standing high blood pressure, high cholesterol, an enlarged prostate and chronic obstructive pulmonary disease (COPD), for which he was taking medications. He had also been diagnosed with rectal cancer 20 years beforehand and received various treatments over the years. He and his wife of 50 years had been sexually inactive since that cancer treatment, he told his doctors.

What happened next: After weeks spent in and out of the hospital, the man went to an emergency room after his skin suddenly became intensely itchy. He had a red, scaly rash on his calves. A neurological exam revealed "normal motor strength, sensation, reflexes, coordination, and gait," the doctors wrote in a report of the case.

At the ER, the patient was questioned further about his medical history, at which point he told doctors that, during his military service as a young man, he'd had unprotected sex with multiple casual partners. He reported being treated for various sexually transmitted infections (STIs) during that time but had forgotten the specific diagnoses.

Tests revealed that the patient was anemic and that his urine contained blood and an abnormal amount of protein. Additionally, a test for autoimmune diseases found abnormally high levels of antinuclear antibodies, which target the control centers of cells that house DNA. Because the patient had recently had facial-nerve palsy, the doctors analyzed his cerebral spinal fluid — the clear fluid that surrounds the brain and spinal cord. This revealed elevated levels of white blood cells, which hinted at an active infection.

The diagnosis: While tests for HIV and tuberculosis came back negative, an assay for Treponema pallidum, the bacterium that causes syphilis, was positive, confirming that the patient had an active syphilis infection.

Syphilis infections can progress through four stages, each with different symptoms. If an infected person doesn't get effective treatment during the primary and secondary stages, the bacteria can go latent, sometimes for decades. And in a minority of cases, latent syphilis can awaken and cause a late, or tertiary, infection.

Based on his positive T. pallidum test, rash, general unwell feeling, abnormal liver results, high urinary protein count, leg swelling, facial drooping and swollen lymph nodes, the man's doctors diagnosed him with secondary syphilis with early neurosyphilis, in which the bacteria attack the nervous system.

The treatment: The patient had been given a single injection of penicillin before the test results confirmed that his infection had neurological involvement. He was subsequently given a 14-day course of intravenous penicillin, which is the recommended treatment for neurosyphilis, according to the case report.

The severe itching was treated with antihistamines, and he was prescribed diuretics to reduce the swelling in his legs. The rash, itching and swelling had improved by his one-month follow-up appointment, and his liver tests and urinary output had normalized.

Public health authorities were informed of the patient's diagnosis, and his wife was referred for testing. The case report does not note whether his wife tested positive for syphilis.

What makes the case unique: Secondary syphilis normally occurs within the first year of an untreated infection and only rarely develops after four years have passed. Normally, smooth, hard sores appear on the mouth or genitals during primary syphilis, and once those sores disappear, secondary syphilis sets in within months, if left untreated.

"Although the patient's history of multiple sexually transmitted infections as a young man prompted testing for syphilis, an exposure from that period would not be expected to explain his current presentation," his doctors wrote.

There's a possibility that the man had a latent infection that recently reactivated, perhaps due to the immune-suppressing effect of his recent steroid treatment. But you'd expect the reactivation to cause only symptoms of tertiary syphilis — like nervous system problems — not symptoms associated with secondary syphilis, like fever, rash and weight loss.

Therefore, exactly when the man contracted the infection is uncertain. "A more recent, unreported exposure must be considered," the doctors wrote.

It is also rare for syphilis to affect the liver and kidneys, occurring in less than 10% of cases, according to the case report.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

This article was first published Feb. 18, 2026.

A years-long malaria control campaign in the Brazilian Amazon nearly eliminated the disease from a city — but then cases rebounded. Now, scientists think they've uncovered why.

The campaign took place in northern Brazil during the construction of the Belo Monte Dam in the Xingu River, one of the largest hydroelectric dams in the world. From 2013 to 2017, the initiative slashed annual malaria rates from more than 1,200 cases to fewer than 60. But the program ended, and within a few years, infections had rebounded to more than 700 cases a year. This time, they were concentrated in the rural communities surrounding the river in the city of Altamira.

In a study published Thursday (July 9) in the journal GeoHealth, scientists analyzed 15 years of malaria surveillance records alongside satellite images of forests around Altamira. Earlier studies have pointed to deforestation and dam construction as a driver of malaria because they can provide habitats for mosquito larvae, which inhabit the forest edge. In Altamira, large stretches of rainforest have been cleared for cattle ranching, logging and settlement along the Xingu River in the decades since the region was first opened up by road-building, leaving a patchwork of cleared land pressed up against the remaining forest.

However, the study found that the malaria resurgence wasn't simply a result of how much forest had been cut down. Instead, cases tracked most closely with the forest edge, the boundary where intact forest meets cleared or open land. There, mosquitoes get everything they need to thrive: shade from the tree line, sunlit pools of standing water for their larvae, and people living or working close by.

The findings highlight how the environment contributes to malaria risk, suggesting that maintaining surveillance in these high-risk landscapes could be just as important as driving cases down in the first place.

"What made Altamira compelling was that the timing gave us something rare, close to a natural experiment," study co-author Eloise Skinner, an epidemiologist and postdoctoral research fellow at the University of Queensland in Australia, told Live Science in an email. The results of that natural experiment could help Brazil in its efforts to eliminate malaria from the country in the next decade, she said.

A program tied to temporary funding

The researchers tracked malaria trends before, during and after the construction of the Belo Monte Dam. Before construction began, malaria was already a persistent problem in the region; Altamira city alone reported more than 1,200 cases a year.

As thousands of workers moved in, local health authorities and the dam's developers rolled out an intensive control program that involved spraying insecticides indoors, using mosquito nets, and deploying rapid diagnosis and treatment when cases did emerge. The goal was to head off outbreaks spread by Nyssorhynchus darlingi, the mosquito that carries the malaria-causing parasite in the Brazilian Amazon.

Mosquitoes pick up the parasite that causes malaria by feeding on the blood of infected people, and they can then spread that parasite to others they bite. Treating infected people quickly can help break that chain of transmission.

Cases plummeted despite the influx of workers, but once construction wrapped up and the program lost its funding, malaria came back.

To understand what drove the resurgence, the researchers combined three streams of data. Case records came from Brazil's national malaria surveillance system and covered 150 health centers in Altamira over 15 years. The team layered on temperature, forest cover and rainfall data, since both shape how favorable an area is for mosquito breeding and how efficiently the malaria parasite develops inside mosquitos. Plus, they added an estimate of travel time between each cluster of cases and the nearest town, as a proxy for how easily people and the diseases they carry might move around.

From the observations, the forest edge consistently emerged as the strongest predictor of increased malaria cases. For every 1% increase in the perimeter of the forest edge, malaria cases rose by roughly 0.7%; for every 1% increase in Altamira's population, who are located at the forest edge, cases rose by about 1.4%.

The rebound wasn't evenly distributed. Before the dam was built, most of Altamira's malaria cases came from clusters inside the city itself. Afterward, that pattern flipped: by 2020, the roughly 700 annual cases were concentrated almost entirely in remote, rural clusters near forest edges. Meanwhile, Altamira's urban center stayed comparatively protected, much as it had during construction.

"When the funded program wound down, malaria came back to the communities that are hardest for the health system to reach," Skinner said. "The city stayed protected, most likely because fast diagnosis and treatment are easier to deliver and keep going in a town."

That leaves the same communities exposed twice over, Skinner said. The places that are already the hardest to reach with health services also sit where the ecological risk is the highest.

But this pattern could point to solutions. The resurgence didn't scatter unpredictably. It came back to the same kind of place — rural communities at the forest edge — each time. That's the kind of risk that can be anticipated in the future.

Brazil aims to eliminate locally acquired malaria by 2035. Skinner said Altamira's near elimination of the disease, and its rebound within a few years of the control program ending, is a warning for that effort. When a community contains a strong environmental driver for malaria, like forest-edge ecosystems, stopping a control program short is sure to let the disease climb back.

"Because the resurgence wasn't diffuse, we can predict where malaria is likely to return first," Skinner said. "The message for a 2035 goal isn't only that elimination needs sustained investment. It is that where the environment drives risk, that risk is predictable, and planning for it from the start is what lets the money go where it matters most."

At least 20 people across 17 states have been hospitalized due to severe gastrointestinal illness as more than 1,000 cases of the parasitic infection cyclosporiasis have been reported across the country, the U.S. Centers for Disease Control and Prevention (CDC) reports.

The CDC and the Food and Drug Administration (FDA) are investigating several clusters of the illness in Illinois, New York, Pennsylvania and Texas, according to CNN. However, the worst-hit state so far is Michigan, with 1,251 cases reported as of July 9, the Michigan Department of Health and Human Services (MDHHS) reported. According to the Associated Press (AP), this marks the biggest cyclosporiasis outbreak in the state's history.

Cyclosporiasis is a gastrointestinal illness caused by the protozoan parasite Cyclospora cayetanensis, which can enter the body when someone consumes food or water contaminated with the parasite. It then infects the small intestines, invading epithelial cells that line the gut, causing inflammation and leading to watery and often "explosive" diarrhea, according to the CDC. Symptoms usually kick in around a week after infection and can last over a month without antibiotic treatment. While the illness can go away on its own, it is also common for symptoms to disappear for a bit and then return.

Cyclosporiasis is not usually life-threatening, but it can cause severe illness and dehydration, particularly in young children, older adults and people with compromised immune systems. In rare cases, the condition may lead to complications like biliary disease, in which the flow of bile gets blocked and impacts the liver and digestive health, according to the MDHHS.

As of July 1, there was no evidence of a single, multistate outbreak of cyclosporiasis, but the CDC is investigating several clusters. According to an email from the health agency, many of the clusters appear to be linked to Mexican-style restaurants, a chain of grocery stores and a catered event, CNN reported. The FDA is conducting trace-back investigations on white and green onions, cucumbers and cilantro, according to CNN.

Meanwhile, the MDHHS warned that, while the source of the current outbreak is still uncertain, previous Cyclospora outbreaks have been linked to contaminated fresh produce, including raspberries, basil and bagged salad.

Cyclosporiasis cases tend to rise during the spring and summer, with May 1 to Aug. 31 considered "cyclosporiasis season," according to the CDC. However, there have been more cases than usual this year: Whereas Michigan typically reports 50 cases over a whole year, the state has seen over 1,000 cases in just a few weeks, the AP reported.

Compared with outbreaks of E. coli and Salmonella, clusters of Cyclospora are much harder to trace back to their source. This is because the parasite can reproduce sexually, meaning its genetic material is mixed up with each generation, according to Charles River Laboratories. However, Dr. Natasha Bagdasarian, Michigan's chief medical executive, told the AP that "there is clearly a linked outbreak happening right now."

To minimize your risk of becoming infected with Cyclospora, wash all fruits and vegetables thoroughly before eating them; cut away any bruised or damaged areas; and refrigerate cut, peeled or cooked produce as soon as possible, the Michigan Department of Agriculture and Rural Development recommends. If you are experiencing sudden gastrointestinal issues, health officials suggest you visit your local health care provider.

This article is for informational purposes only and is not meant to offer medical advice.

The hantavirus outbreak that struck a cruise ship in April, killing three people and sparking fears of further spread, is over, the World Health Organization (WHO) has announced.

"Today, the final contact of a person exposed to hantavirus on the cruise ship MV Hondius completed their quarantine period, tested negative and returned home. No further cases have been reported since the 25th of May," Tedros Adhanom Ghebreyesus, the WHO's director-general, said in his opening remarks at a news conference Thursday (July 2). "We are therefore very pleased to say that WHO considers the outbreak of hantavirus over."

The total number of cases linked to the outbreak was 13. All those affected were either passengers or crew on the ship.

The outbreak began aboard the Dutch-flagged cruise ship MV Hondius after it departed southern Argentina on April 1. It involved the Andes virus, the only known hantavirus that can spread between people.

Hantaviruses are rodent-borne viruses that are found in the Americas, Europe and Asia and spread to humans relatively rarely, usually via contact with the urine, droppings or saliva of infected rodents. The Andes virus, however, has sparked short chains of human-to-human transmission in the past.

Before public health authorities were informed of the cases on MV Hondius, several dozen people disembarked the vessel on the island of St. Helena. To find them, authorities launched an international contact-tracing operation, tracking down more than 650 contacts in total who were then followed by health authorities in 33 countries and territories, according to the WHO.

Additionally, health authorities coordinated the monitoring, care and transport of the remaining passengers and crew aboard MV Hondius.

Of these contacts, those considered at the highest risk of infection were then quarantined and monitored for up to 42 days, because sometimes, hantavirus symptoms don't show up until weeks after exposure to the virus. Depending on their jurisdiction and degree of exposure, some contacts quarantined at home while others stayed in specialized facilities.

The initial unchecked travel of some contacts, alongside the virus's long incubation period, prompted concern from the public that the cluster of cases could explode into an enormous outbreak, or even a global pandemic. Many infectious-disease experts emphasized that the Andes virus does not spread easily between people and that the containment effort was going well, so the risk of a large outbreak was low. Still, some experts raised concerns that the international travel of contacts could trigger pockets of the deadly disease, and some argued that the Andes virus does have "pandemic potential."

Now, with the final contact having completed their quarantine period and no further cases reported, the WHO has declared the outbreak over. All of the contacts who were repatriated to the U.S. completed their quarantine period by June 21.

"WHO will continue working with governments and partners to advance our understanding of this outbreak and of hantavirus more generally," Tedros said. "We are also coordinating a study involving 21 countries to understand how the disease develops, which will support the development of diagnostics, therapeutics and vaccines for future outbreaks."

Besides rigorous contact tracing, the WHO credited the coordinated actions of national public health bodies as being vital to preventing the further spread of the disease. These measures included the response of the Spanish government, which created a safe zone on the island of Tenerife for the ship's remaining passengers to disembark before they were repatriated under quarantine.

As the hantavirus outbreak concludes, there's an ongoing Ebola outbreak in the Democratic Republic of the Congo and an outbreak of the Marburg virus in Uganda. These and future outbreaks will require similarly robust international cooperation, the WHO emphasized.

"The outbreaks of hantavirus, Ebola and Marburg all show why there is no alternative to international cooperation in the face of international threats," Tedros said. "No country alone can fight."

This article is for informational purposes only and is not meant to offer medical advice.

An 11-year-old boy in Ontario, Canada, has died after being bitten by a rabid bat that was resting on his face as he slept. The boy had no obvious bite or scratch marks and didn't show symptoms for the first 19 days after the incident, his doctors report.

While on vacation with his parents at a cottage in northern Ontario in 2024, the boy was woken up in the night by a bat on his nose and mouth, according to a report published in the Canadian Medical Association Journal on June 29. His father caught the bat in a cooking pot and released it outside, and because the child had no visible injuries and the bat did not seem to be particularly aggressive, his parents decided not to seek a medical assessment, the report noted.

A few weeks later, the child began to experience tingling, numbness and swelling on the right side of his face. When he was examined at his local hospital his vital signs appeared to be normal, aside from an elevated heart rate and white blood cell count.

The next day, the boy's symptoms worsened: he lost feeling in the right side of his face and his speech was beginning to slur. While waiting in hospital, he developed a fever, confusion, hallucinations and difficulty swallowing, followed by excessive production of saliva.

After four days in intensive care at McMaster Children's Hospital in Hamilton, Ontario, the child tested positive for rabies, and after five days his brain stem reflexes were absent, indicating a total loss of brain stem function. Seventeen days after admission, following a consultation between his family and medical experts, he was taken off life support and died.

Rabies is a viral disease that primarily affects the central nervous system, according to the CDC. It is mainly spread through bites and scratches from infected animals, with bats accounting for the majority of cases in North America, according to the boy's doctors.

"Bats pose a particular risk because bites or scratches may be small and are easily overlooked, and patients may not recollect or recognize a bat exposure," the medical team wrote in their report.

According to a report in the Journal of Virology in 2013, silver-haired bats (Lasionycteris noctivagans), are responsible for the majority of rabies cases in Canada. Skunks, foxes and raccoons also often carry the disease.

The rabies virus must travel to the brain before symptoms can occur, but once a patient develops symptoms the infection is almost 100% fatal, with most deaths occurring within one to two weeks of symptom development. However, prompt treatment after exposure — including wound cleaning, antibody administration and a series of vaccines — is nearly always effective at preventing the disease, according to the CDC.

Rabies in humans is very rare in North America, with fewer than 10 deaths reported in the U.S. every year, according to the CDC. In Canada, only 28 human fatalities have been reported since 1924, according to the Canadian Veterinary Medical Association. Even so, the boy's doctors have emphasized the importance of prompt medical attention following exposure to bats and other animals that could carry the disease.

"Early recognition of exposure and timely PEP [postexposure prophylaxis] remain the only effective means of rabies prevention," they wrote. "Any direct human contact with a bat, even in the absence of a visible bite or scratch, is an indication for PEP."

They added that rabid bats do not always display the classic symptoms commonly associated with rabies, such as aggressive behavior and frothing at the mouth. "Any direct human contact with [a] bat is considered high risk," they added.

This article is for informational purposes only and is not meant to offer medical advice.

The patient: A 28-year-old woman in New Hampshire

The symptoms: In March 2020, the woman developed a high fever, chest tightness, shortness of breath and diarrhea, and she lost her sense of smell and taste. She also experienced coughing fits so intense that they caused her to faint. Based on these symptoms, her primary care provider diagnosed her with COVID-19, although she was not formally tested for the illness due to the lack of diagnostic testing available at the time.

After her diagnosis, she did not seek further medical care due to concerns about out-of-pocket costs, according to a report of the case.

What happened next: Three weeks after her symptoms started, the patient felt well enough to work from home. However, four weeks after that, many of her symptoms returned. She also noticed new feelings of disorientation and felt that "something was off with faces." Her primary care doctor suggested she go to an emergency room, where a CT scan was taken of her brain. The scan didn't show any active bleeding, the report notes, and she was discharged.

In June 2020, the patient spent time with family for the first time since catching COVID-19 and found she could not recognize her father or visually distinguish him from her uncle. She still recognized people by their voices, though.

The patient worked part time as a portrait artist; she used to be able to check her reference photos every 15 to 30 minutes but found she now struggled to hold the details in her mind. She told doctors that "faces are like water in my head," according to the case report.

The patient also had trouble doing everyday tasks, such as navigating her local grocery store or finding her way back to her car in a parking lot. In November 2020, she also started having balance issues and frequent migraines.

The diagnosis: Based on her wide-ranging and relapsing symptoms and her suspected history of COVID-19, doctors diagnosed the patient with post-acute sequelae of COVID-19 (PASC), now known as long COVID. They diagnosed her difficulties with recognizing faces as "face blindness," or prosopagnosia.

Roughly 2.5% of the general population is thought to be born with some degree of face blindness, while others can acquire the condition later in life. The exact number of people with acquired prosopagnosia is unclear, but some estimates suggest roughly 1 in 30,000 people in the U.S. are affected.

Many people with acquired prosopagnosia also have issues navigating familiar spaces. That was also the case with this patient, likely due to the "proximity of brain regions critical for scene and face processing," the case report authors noted.

To assess the extent of the patient's prosopagnosia, doctors had her complete several tests of facial memory, which asked her either to memorize strangers' faces or recognize celebrities' faces. The patient performed markedly worse on these tests than 10 women of similar age who were used as a comparison group.

However, she performed as well as the comparison group on other types of cognitive tests, suggesting her deficits were fairly specific to faces. She also got normal scores on tests of facial perception — the ability to recognize that a face is a face — so her face blindness seemed tied more to memory deficits for faces, the report authors said.

The treatment: The case report does not detail a specific course of treatment, and in general, few treatments exist for face blindness. If there's a clear cause for the deficit — such as a tumor in a key part of the brain for facial processing — addressing that underlying issue can help reverse acquired face blindness.

If the condition ends up being permanent, there are various strategies that can help patients cope. For instance, "perceptual training" can improve patients' ability to identify and remember the features of a person's face. Additional strategies include training people to use other cues, like voices and social context, to identify people.

What makes the case unique: In this patient's case, the report authors suspect that her COVID-19 infection triggered her face blindness either acutely or in the aftermath of the infection.

Various infections have been tied to face blindness; both bacterial meningitis and Whipple disease (caused by the bacterium Tropheryma whipplei) have been flagged as culprits, although such cases are uncommon. In a second known case involving COVID-19, a different person developed face blindness after an infection but had also had a stroke in the right hemisphere of their brain, a known cause of prosopagnosia.

The 28-year-old woman, by contrast, wasn't thought to have suffered a stroke, and it's unclear exactly how COVID-19 led to her facial processing issues.

The case report authors surveyed more than 50 other people with long COVID, to see if they also had signs of face blindness. While many showed general declines in visual recognition and navigational abilities, the group didn't have a specific problem with faces. So while long COVID is known to cause a range of neurological issues, it appears that face blindness is a rare consequence.

For more intriguing medical cases, check out our Diagnostic Dilemma archives.

This article is for informational purposes only and is not meant to offer medical advice.

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