Dear Editor,

Olmez, Tas, Saritas, Aslan, and Yilmaz (2015), in their recently published "Clinical Case Study," found a tapeworm partially located in the stomach, and with a portion in the intestine, of a female patient. They indicated that the tapeworm was identified as Taenia saginata by a parasitologist, however, without specifying the technique carried out in the diagnostic procedure. We assume that the diagnosis of T. saginata infection was based on the morphology of the gravid proglottids because the morphology of the eggs released by the tapeworm would lead only to a generic, but not a specific, result.

In their remarks on human taeniasis, the authors consider exclusively two species as possible causal agents of the parasitization; that is, T. saginata and T. solium, ignoring the third human Taenia species, T. asiatica (Eom & Rim, 1993). The morphology of T. asiatica overlaps with that of T. saginata; therefore, its specific diagnosis is only possible by using molecular methods; for instance, multiplex polymerase chain reaction (Jeon et al., 2009). Unless molecular diagnosis is carried out, the tapeworm could belong to T. saginata or T. asiatica species. The most important feature that differentiates T. asiatica from T. saginata is its life cycle. The intermediate hosts of T. saginata are cattle. However, pigs are the intermediate hosts of T. asiatica. Although initially considered an exclusively Southeastern Asian parasite, its presence out of Asia is currently being considered (Galan-Puchades & Fuentes, 2014; Lucy, Sprong, Ortega, van der Giessen, & Fayer, 2014) because, apparently, there is no reason for a parasite with cosmopolitan hosts (humans and pigs) to be confined to a specific continent. Only in case the patient has never eaten pork, could it be possible to assess that the tapeworm she harbored was indeed T. saginata.

We would also like to clarify some information the authors of the article detailed relative to the risk factors to acquire this kind of parasitization. They wrote, "Patient age and consumption of contaminated water and eating raw liver are the main risk factors for tapeworm infestation (sic)." Regarding the first part of the sentence, by means of drinking water, it is not possible to acquire the parasitization the authors are dealing with. The only way to acquire taeniasis is by means of eating raw or undercooked beef (T. saginata taeniasis) or eating pork (T. solium and T. asiatica taeniasis) containing the larval stage (cysticerci) of the parasite. Drinking water could lead to another type of infection, that is, cysticercosis. The eggs shed in feces of humans suffering from taeniasis contaminate the environment (water, soil, vegetables, hands, etc.). If humans accidentally ingest T. solium eggs, they could develop the extraintestinal larval stages, suffering then from cysticercosis, a sometimes fatal disease when the cysticerci are located in the central nervous system (neurocysticercosis).

Concerning the second part of the sentence, "...and eating raw liver are the main risk factors for tapeworm infestation," eating raw (or undercooked) pork liver is the main risk factor to exclusively acquire T. asiatica. Neither the cysticerci of T. saginata in cattle nor those of T. solium in pigs show any specific tropism for the liver. Only the cysticerci of T. asiatica are specifically located in pig liver (Eom & Rim, 1993).

Finally, the authors state that T. saginata taeniasis is a common infection in Turkey. It would be really intriguing to ascertain if among those pork-eating patients presenting T. saginata-like tapeworms, T. asiatica could also be present in such a strategically located country between Asia and Europe.

Maria Teresa Galan-Puchades, PhD

Professor

Marius Vicent Fuentes, PhD

Titular Professor

Department of Cellular Biology and Parasitology

Faculty of Pharmacy

University of Valencia

Valencia, Spain

[email protected]

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