SPRINGFIELD - It's a disease so uncommon it's usually only referenced in the punchline of a pirate joke, but a clinic on High Street has seen a high number of scurvy cases over the past five years.

Baystate High Street Health Center Adult Medicine found at least 30 cases among its patients in five years, beginning in 2010, according to a report by New England Public Radio, which says this is more diagnoses than in any previous study of its kind.

Scurvy can cause bleeding gums, rough skin, bleeding under the skin, swollen joints, depression and many more symptoms. Smoking can exacerbate the problem. If it's not treated, scurvy can be fatal.

The disease was common in pirates and sailors in the 18th century, as they went for long stretches of time without access to fruits and vegetables -- a key problem that leads to scurvy in modern times, as well.

A 2013 report by the Centers for Disease Control and Prevention, focused mostly on refugees resettling in developed countries, found that 14 percent of males and 10 percent of females in the U.S. suffer from a vitamin C deficiency, which the report equates with scurvy.

This is caused by "chronic malnutrition, alcoholism, and restrictive diets devoid of fruit and vegetables," the report states, and it's not clear how many cases there are among refugees in the U.S.

NEPR quotes Dr. Eric Churchill of the High Street clinic: "You can have a handful of McDonald's ketchup packets a day, and that'll give you enough vitamin C to keep yourself from contracting scurvy."

Good sources of vitamin C include oranges, strawberries, several kinds of peppers, tomatoes, broccoli and carrots.

The Mayo Clinic says the recommended daily vitamin C intake is 65 to 90 milligrams, and the upper limit is 2,000 milligrams. Another name for vitamin C is ascorbic acid, which a doctor may recommend to treat scurvy.

Vitamin C also gets added to some processed foods and is found in multivitamins. Minor dietary changes can reverse a deficiency and prevent scurvy.

The NEPR report quotes Churchill as saying more doctors should keep scurvy in mind, and he hopes his study leads to more research.