While researchers continue to study lasting, long-term effects following infection from the novel coronavirus, new reports reiterate the so-called “long haulers” experiencing a distorted sense of smell, catching odd, unpleasant fishy, sulfur and burning odors.

Professor Nirmal Kumar, consultant ENT surgeon and president of ENT UK, attributed the warped sense of smell to parosmia, calling it “very strange and very unique,” per a report from Sky News. According to the National Institutes of Health, parosmia signals an altered “perception of odors,” “or when something that normally smells pleasant now smells foul.”

Though reports of coronavirus long haulers experiencing foul odors cropped up earlier this year, parosmia has yet to make it onto the Centers for Disease Control and Prevention’s (CDC) list of coronavirus-related symptoms, though the agency notes the list “does not include all possible symptoms.”

“CDC will continue to update this list as we learn more about COVID-19,” reads the agency’s web page. One expert previously elaborated on sense of smell in the context of viral pathogens to Fox News.

“There are two sensory systems in our nose. We are able to detect pleasant fragrances by way of the olfactory nerve, whereas dangerous, toxic smells are detected by the trigeminal nerve,” Dr. Susan Shin, an assistant professor of neurology at Mount Sinai Hospital, previously told Fox News. “The trigeminal nerve is likely more resilient to effects of a viral pathogen compared to the olfactory nerve because we need it to detect dangers in our environment, such as smelling smoke from a fire.”

Kumar said thousands of patients across the UK are under treatment for loss of smell, coined anosmia and some are now experiencing the largely unpleasant odors associated with parosmia, per the outlet. The professor explained the patients’ distorted smell stems from “olfactory hallucinations.”

Earlier this spring, Kumar and ENT UK reported growing numbers of patients presenting in clinics with a “sudden, unexplained loss of sense of smell.” Kumar says the organization was among the first to suggest that the patients’ loss of smell was due to coronavirus infection.

“This virus has an affinity for the nerves in the head and in particular, the nerve that controls the sense of smell,” the professor told the outlet. “But it probably affects other nerves too and it affects, we think, neurotransmitters — the mechanisms that send messages to the brain.”

“What this means is the virus is affecting the nerves in the roof of the nose — it’s like a shock to your nervous system and the nerves aren’t functioning,” Kumar added, per another report.

While one 24-year-old patient in the UK, Daniel Saveski, reported a “burning, sulfur-like odor” ever since he briefly lost his sense of smell for two weeks in March, another patient in her mid-50s described the phenomenon as “disgusting” and spoke of a “sickly sweet smell.”

“Most things smelled disgusting, this sickly sweet smell which is hard to describe as I’ve never come across it before,” Lynn Corbett of Selsey in England told Sky News.

Chrissi Kelly, a board member of AbScent, a UK charity supporting smell disorders, has advised those affected to avoid foods triggering unpleasant smells, eat room temperature or cold foods to tamp down on rising smells and to opt for simple, bland foods like rice and pasta in the meantime. 

Separate research in late October from the UK’s King’s College London analyzed symptoms of 4,182 coronavirus patients who had logged their illness using a COVID Symptom Study app. They noted 558 of the patients saw symptoms last longer than 28 days, while 189 suffered for over eight weeks and 95 patients with symptoms reported that they lasted longer than 12 weeks.

The researchers found that among the long-COVID patients, symptoms were most commonly listed as fatigue, headache, dyspnea and anosmia and were more likely to occur in older patients, those with a higher BMI and in patients who were female. According to the most recent reports, the distorted smell, or parosmia, may more greatly affect younger patients and medical workers.