When doctors at St Luke’s International Hospital in Tokyo examined a patient with a five-day history of sore throat, they expected to find some hyperemia, swollen lymph nodes and, maybe some inflammation over the palate. Instead, they were left stunned by a wriggling black worm moving in the left tonsil.
According to the case study published in the American Journal of Tropical Medicine and Hygiene, the 25-year-old woman started experiencing pain and irritation in her throat shortly after consuming Sashimi. Sashimi is a Japanese delicacy consisting of raw fish or meat thinly sliced and usually eaten with soy sauce.
The worm was pulled out by the doctors with the help of a pair of tweezers. It measured 38 millimeters (1.5-inches) long. The worm was seen to be molting the outer cuticle, revealing it to be a fourth stage larva of Pseudoterranova Azaras, an uncommon parasitic roundworm usually found in fish and marine mammals such as seals and walruses. DNA PCR was conducted to identify the worm.
Tingling throat syndrome – a rare effect of eating raw or uncooked fish or squid
Some people report a tingling sensation along with a cough after eating raw or uncooked fish or squid. It is believed to be caused by the worm’s movement in the throat. People may also experience vomiting and coughing as a symptom, which helps expel the worm out of the body.
Fortunately, the patient’s symptoms were seen to quickly resolve after removal of the worm, and all her blood test results were seen to be normal.
Humans are usually infected after ingesting raw or uncooked squid or fish containing the larvae. Infection of the gastrointestinal tract is common with the parasite. Cases are usually higher in areas with high raw fish consumption. More than 700 cases have been reported in Japan, North Pacific countries, South America, and the Netherlands.
While oropharyngeal involvement is rare, the study shows that there’s a rise in the number of cases worldwide as the consumption of sushi and sashimi gains popularity around the world.
Fukui, S., Matsuo, T., & Mori, N. (2020). Palatine Tonsillar Infection by Pseudoterranova azarasi. The American Journal of Tropical Medicine and Hygiene, 103(1), 8-8. doi:10.4269/ajtmh.20-0175