Diagnosis of taeniasis is mainly using stool sample, particularly by identifying the eggs. However, this has limitation at the species level because tapeworms basically have similar eggs. Examination of the scolex or the gravid proglottids can resolve the exact species. But body segments are not often available, therefore, laborious histological observation of the uterine branches and PCR detection of ribosomal 5.8S gene are sometimes necessary. Ziehl–Neelsen stain is also used for T. Saginata and T. Solium, in most cases only the former will stain, but the method is not entirely reliable. Loop-mediated isothermal amplification (LAMP) is highly sensitive (~2.5 times that of multiplex PCR), without false positives, for differentiating the taenid species from faecal samples.
To date the most relevant test for T. Asiatica is by enzyme-linked immunoelectrotransfer blot (EITB). EITB can effectively identify asiatica from other taenid infections since the serological test indicates an immunoblot band of 21.5 kDa exhibited specifically by T. Asiatica. Even though it gives 100% sensitivity, it has not been tested with human sera for cross-reactivity, and it may show a high false positive result.
Taeniasis is generally asymptomatic and is diagnosed when a portion of the worm is passed in the stool. It is not fatal, although cysticercosis can cause epilepsy and neurocysticercosis can be fatal.
Taenia solium => Infection by T. Solium is normally asymptomatic. Heavy infection is indicated by intestinal irritation, anaemia, and indigestion.
There are accidental consumptions of eggs of T. Solium from contaminated vegetables or water. The eggs enter the intestine where they develop into larvae. The larvae enter the bloodstream and invade host tissues. This clinical condition, called cysticercosis, is the most frequent and severe disease caused by any tapeworm. It can lead to severe headaches, dizziness, occasional seizures, dementia, hypertension, lesions in the brain, blindness, tumor-like growths, and low eosinophil levels. It is the cause of major neurological problems, such as hydrocephalus, paraplegy, meningitis, convulsions, and even death.
Taenia saginata => Taenia saginata infection is asymptomatic, but heavy infection causes weight loss, dizziness, abdominal pain, diarrhea, headaches, nausea, constipation, chronic indigestion, and loss of appetite. It can cause antigen reaction that induce allergic reaction. It is also a rare cause of ileus, pancreatitis, cholecystitis, and cholangitis.
Taenia asiatica => Taenia asiatica is also usually asymptomatic. The only severe case was in a 60-year-old woman at the Mackay Memorial Hospital in Taiwan. Her stomach and intestine were severely damaged with active bleeding from ulcers caused by a single tapeworm.
In pigs, the cysticercus can produce cysticercosis. Cysts develop in liver and lungs. (T. Saginata does not cause cysticercosis.) Due to its biological similarity to T. Solium, which is the major cause of neurocysticercosis, T. Asiatica may also cause cysticercosis.