Taenia crassiceps infection--an unusual presentation of a tapeworm diagnosed by FNA cytology and PCR

Comprehensive Diagnosis, Treatment, and Outcome of Taenia crassiceps Cysticercosis in a Ring-Tailed Lemur (Lemur catta) from a Croatian Zoo: No Longer Unusual?

Taenia crassiceps is a zoonotic tapeworm of the genus Taenia that is distributed throughout the Northern Hemisphere. Wild and domestic carnivores are final hosts, while rodents and rabbits are primarily intermediate hosts, although many other mammals may harbour the larval stage, Cysticercus longicollis. This case report aims to describe C. longicollis infection in a lemur and molecularly characterise the isolated parasite. The excised lesion was subjected to morphological and histopathological examination, which revealed cysticerci of the tapeworm. Formalin-fixed and paraffin-embedded block (FFPEB), as well as the cysticerci fixed with formalin stored for one year, were subjected to molecular analysis, which aimed at detecting the partial mitochondrial cytochrome c oxidase subunit 1 (cox1) gene of Taenia sp. Based on the morphological characteristics, the parasite was identified as a metacestode of T. crassiceps. The presence of the cox1 gene was detected using polymerase chain reaction (PCR) in all samples. A randomly selected PCR product was sequenced and compared with other sequences from the GenBank database, confirming that the detected parasite was T. crassiceps. This article reports the first case of T. crassiceps cysticercosis in a lemur (Lemur catta) in Croatia and emphasises the potential risk of transmission from wild carnivores.

Molecular Confirmation of Taenia crassiceps Cysticercosis in a Captive Ring-Tailed Lemur (Lemur catta) in Poland

(1) Background: Taenia crassiceps is a cosmopolitan tapeworm endemic to the northern hemisphere with an indirect lifecycle. Its definitive hosts are carnivores, and its intermediate hosts are rodents and rabbits. Nonhuman primates in zoos appear to be highly susceptible to T. crassiceps cysticercosis. The aim of this study was to confirm the presence and the molecular characterization of T. crassiceps cysts isolated from a captive ring-tailed lemur. (2) Methods: Surgery revealed multifocal, transparent saccules containing several thin-walled tapeworm cysticerci. In some of the metacestodes, single or multiple exogenous buds from daughter cysticerci were spotted. A molecular analysis was performed to confirm our morphological examinations, using two protocols to obtain the partial nad1 and cox1 genes of the Taenia sp. (3) Results: On the basis of morphological features and molecular analysis, the cysticerci were identified as T. crassiceps metacestodes, and products taken from the PCRs were sequenced. With respect to interpreting the sequencing results of the obtained amplicons, we compared them with data in the GenBank database, proving that, in this case, the causative agent was indeed T. crassiceps. (4) Conclusions: The received data can be used to supplement descriptions of this species. To the best of our knowledge, this is the first case of cysticercosis caused by T. crassiceps in a nonhuman primate in Poland.

Wildlife-transmitted Taenia and Versteria cysticercosis and coenurosis in humans and other primates

Wild mustelids and canids are definitive hosts of Taenia and Versteria spp. while rodents act as natural intermediate hosts. Rarely, larval stages of these parasites can cause serious zoonoses. In Europe, four cases of Taenia martis cysticercosis have been diagnosed in immunocompetent women, and two cases in zoo primates since 2013. In North America, a zoonotic genotype related but distinct from Versteria mustelae has been identified in 2014, which had caused a fatal infection in an orangutan and liver- and disseminated cysticercoses in two severely immune deficient human patients in 2018, respectively. Additionally, we could attribute a historic human case from the USA to this Versteria sp. by reanalysing a published nucleotide sequence. In the last decades, sporadic zoonotic infections by cysticerci of the canid tapeworm Taenia crassiceps have been described (4 in North America, 8 in Europe). Besides, 3 ocular cases from North America and one neural infection from Europe, all in immunocompetent patients, 6 cutaneous infections were described in severely immunocompromised European patients. Correspondingly, besides oral infections with taeniid eggs, accidental subcutaneous oncosphere establishment after egg-contamination of open wounds was suggested, especially in cases with a history of cutaneous injuries at the infection site. Taenia multiceps is mainly transmitted in a domestic cycle. Only five human coenurosis cases are published since 2000. In contrast, T. serialis coenurosis (1 human case since 2000) is primarily transmitted by wild canids. The etiological diagnosis of exotic cysticercoses is challenging. Usually, clinical material does not allow for a morphological identification, and serological tests are not available. These limitations have partly been overcome by molecular tools. Without claiming any dramatic emergence of cysticercoses and coenuroses transmitted by wild carnivores, further sporadic cases of such ‘exotic’ infections have to be expected.

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Wild canids and mustelids transmit rare but potentially fatal cysticercoses and coenuroses.

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Martens and weasels can rarely transmit dangerous parasitic infections.

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Tapeworm eggs may contaminate wounds and develop locally.

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In North America, the mustelid tapeworm Versteria causes severe human infections.

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Molecular analyses from minute clinical material allows for a specific diagnosis.

Management of a chest-wall soft-tissue tumor caused by an infection with the larval tapeworm pathogen Taenia crassiceps

A chest-wall lesion of an immunocompetent patient was initially suspicious for a malignant tumor. Histopathological and polymerase chain reaction examinations revealed an infection with the larval stage of the tapeworm Taenia crassiceps. Curative resection of the tumorous lesion was performed. Treatment options for immunocompromised patients and patients without known immune defect are discussed, because most of the infections occur in immunocompromised individuals.