In this way, diphyllobothriasis represents an emerging infectious disease in certain parts of the world where cultural practices involving eating raw or undercooked fish are being introduced. References
External links

"Diphyllobothriasis". CDC – DPDx – Laboratory Identification of Parasitic Diseases of Public Health Concern. 2013-11-29. Retrieved 2015-09-05.
Balantidiasis is a protozoan infection caused by infection with Balantidium coli. Symptoms and signs
Usually asymptomatic in immunocompetent individuals, but the symptoms of balantidiasis include:
Intermittent diarrhea
Constipation
Vomiting
Abdominal pain
Anorexia
Weight loss
Headache
Colitis
Marked fluid lossThe most common ones are intermittent diarrhea and constipation or inflammation of the colon combined with abdominal cramps and bloody stools. Transmission
Balantidium is the only ciliated protozoan known to infect humans. Balantidiasis is a zoonotic disease and is acquired by humans via the feco-oral route from the normal host, the pig, where it is asymptomatic. “Contaminated water is the most common mechanism of transmission. Equally dangerous, however, is the ingestion of contaminated food.”

Morphology
Balantidium coli exists in either of two developmental stages: trophozoites and cysts. In the trophozoite form, they can be oblong or spherical, and are typically 30 to 150 µm in length and 25 to 120 µm in width. It is its size at this stage that allows Balantidium coli to be characterized as the largest protozoan parasite of humans. Trophozoites possess both a macronucleus and a micronucleus, and both are usually visible. The macronucleus is large and sausage-shaped while the micronucleus is less prominent. At this stage, the organism is not infective but it can replicate by transverse binary fission.In its cyst stage, the parasite takes on a smaller, more spherical shape, with a diameter of around 40 to 60 µm. Unlike the trophozoite, whose surface is covered only with cilia, the cyst form has a tough wall made of one or more layers.