A Case of Coenurosis in a Wild Rabbit (Lepus sinensis) Caused by Taenia serialis Metacestode in Qinghai Tibetan Plateau Area, China.

Six cystic metacestodes were found in the abdominal muscles of a wild rabbit, Lepus sinensis, in China. The coenurus contained one or more scolices armed with hooklets. Mitochondrial cox1 (1,623 bp) confirmed 98% homology with cox1 of Taenia serialis. This is the first report of T. serialis infection in an intermediate host in the Qinghai Tibetan Plateau Area, China.

Tapeworms detected in wolf populations in Central Italy (Umbria and Marche regions): A long-term study.

Tapeworms are trophically-transmitted and multi-host parasites with a complex indirect life cycle, strictly depending on predator-prey interactions. Their presence in a free-living population, mainly definitive hosts, is arduous to study due to the complexity of collecting fecal samples. However, epidemiological studies on their frequency are crucial from a public health perspective, providing information on food habits and prey selection of predators. The present study aims to update the frequency of tapeworms detected in stool samples by molecular analysis in Italian wolf populations of Umbria and Marche regions collected from 2014 to 2022. Tapeworm's total frequency was 43.2%. In detail, Taenia serialis was detected in 27 samples (21.6%), T. hydatigena in 22 (17.6%), and Mesocestoides corti (syn. M. vogae) in 2 (1.6%). Three samples were identified as M. litteratus and E. granulosus s.s. (G3) and T. pisiformis, with a proportion of 0.8%, respectively. The low frequency of E. granulosus in a hyperendemic area is discussed. The results show for the first time a high frequency of Taenia serialis not comparable to other Italian studies conducted on wild Carnivora; thus, a new ecological niche is conceivable. These findings suggest a plausible wolf-roe deer cycle for T. serialisin the investigated area.

Disseminated Human Subarachnoid Coenurosis.

Background: Traditionally, human coenurosis has been ascribed to Taenia multiceps while neurocysticercosis has been attributed solely to Taenia solium infection. Historically, however, the identification and differentiation of cestodal infection was primarily based on inaccurate morphological criteria. With the increasing availability of molecular methods, the accuracy of identification of the larval cestode species has improved, and cestodal species not typically associated with central nervous system (CNS) infection are now being identified as aetiological agents. Case report: We present a case of a 5-year-old male patient who presented with acute hydrocephalus. Initial MRI revealed multiple cysts in the cerebrospinal fluid (CSF) spaces with a predominance of clumped grape-like cysts in the basal cisterns with resultant acute obstructive hydrocephalus. The child underwent an emergency ventriculo-peritoneal (VP) shunt. A presumptive diagnosis of neurocysticercosis racemosus was made and the child was started on empiric albendazole (15 mg/kg/day) and praziquantel (30 mg/kg/day) treatment, along with concomitant prednisone (1 mg/kg) treatment. Despite prolonged anti-helminthic therapy, the child continued to deteriorate, and endoscopic removal of the 4th ventricular cysts was required. Post-operative MRI revealed radiological improvements, with a reduction in the number and size of cysts, especially in the basal cisterns, with no cysts visualized in the fourth ventricle. DNA was extracted from CSF and cyst tissue using the QiAMP DNA mini kit (Qiagen). The PCR performed on the extracted DNA displayed a band of 275 bp on an agarose gel. The consensus sequence had 97.68% similarity to Taenia serialis 12S ribosomal RNA gene. The child, unfortunately, continued to do poorly, requiring multiple VP shunt revisions for repeated blockage of the VP shunt system, and ultimately demised, despite the 'successful' surgical intervention and continued maximal medical management. Discussion and conclusions: There have been approximately 40 reported cases of human CNS coenurosis, with the assumed etiological agent being confined to T. multiceps. In 2020, the first case of human CNS coenurosis caused by T. serialis was reported. This case involved a single parenchymal lesion in the occipital lobe, which, following complete surgical excision, was confirmed to be T. serialis by mitochondrial gene sequencing. The case we present is the first case of disseminated subarachnoid coenurosis caused by T. serialis. It appears that T. serialis infection can mimic either of the two basic pathological forms of neurocysticercosis, namely, cysticercosis cellulosae or cysticercosis racemosus. We postulate that the term coenurosis racemosus is applicable if CNS T. serialis infection presents with extensive, multiple grape-like bladders proliferating within the subarachnoid space.

A novel intermediate host for Taenia serialis (Gervais, 1847): The European roe deer (Capreolus capreolus L. 1758) from the Monti Sibillini National Park (MSNP), Italy.

Taeniids are multi-host parasites with an indirect life cycle that strictly depends on a predator-prey relationship. Parasites with a complex life cycle may exhibit different degrees of host-specificity at each life stage. Knowing the host breadth is a fundamental concept of the biology and epidemiology of these multi-host parasites. Morphological identification of tapeworms is challenging and occasionally may produce misdiagnosis. Thus, molecular investigations were carried out for the identification of parasitic cysts detected from muscle tissues in a male roe deer necropsied at the Istituto Zooprofilattico Sperimentale dell'Umbria e delle Marche "Togo Rosati" (Central Italy). Sanger sequencing showed 99% query cover, 2e-109 e-value, and 100% identity with Taenia serialis. The exact definitive host was not revealed in this report, but red foxes and Italian wolves may play a significant role as being widespread within the area. Wildlife surveillance is crucial to monitor for human and animal health since global distribution and flexibility in intermediate hosts of many and even more critical taeniids species may enlarge their host range.

First case of human neurocoenurosis caused by Taenia serialis: A case report.

Human coenurosis is caused by the larval stages of Taenia species, mainly Taenia multiceps and Taenia serialis. T. multiceps has been reported to cause human central nervous system (CNS) infections, but no CNS case caused by T. serialis has been reported. The authors report the first case of human neurocoenurosis caused by T. serialis, which was confirmed by mitochondrial DNA analysis. A 38-year-old man presented with visual disturbance and headache, and subsequent magnetic resonance imaging (MRI) revealed a ring-enhancing cystic lesion in the left occipital lobe. Biopsy was performed, and the resultant histopathological diagnosis was that of low-grade B-cell lymphoma. Chemotherapy was initiated, but a subsequent MRI showed increased ring enhancement. Due to the unexpected clinical course, a surgical resection of the lesion was performed. The lesion was completely removed. Pathological examination showed multiple scolices with hooklets, suckers, and numerous calcareous corpuscles. Therefore, the diagnosis of neurocysticercosis was made. However, mitochondrial DNA analysis showed that the disease was definitively coenurosis caused by T. serialis. Albendazole was administered, with no evidence of recurrence at 12 months following the operation. In this study, we demonstrate that T. serialis can cause CNS infection and that genetic analysis is recommended to establish a definitive diagnosis.

Severe coenurosis caused by larvae of Taenia serialis in an olive baboon (Papio anubis) in Benin.

In March 2017, a captive male juvenile (ca. 6 months old) olive baboon (Papio anubis) was brought to a primate rescue center in Benin with multiple subcutaneous swellings of unknown aetiology. At the general inspection of the body, around 15 partially mobile masses of variable sizes were found in different locations across the body. Following two surgical procedures, several cyst-like structures were removed and placed either in 10% formalin or in absolute ethanol. The cysts had a typical coenurus-like morphology. Genomic DNA was extracted from one cyst using a commercially available kit. The molecular characterization was performed by PCR amplification and sequencing of a region of the nuclear ITS-2 rDNA and a fragment of the mitochondrial 12S rDNA gene, revealing its identity as T. serialis, with 88%-98% similarity to T. serialis isolates from USA, Japan and Germany This study reports a new host for the larval form of T. serialis and confirms the role of primates as intermediate host, highlighting also the risk for human infection. Further genetic studies from multiple geographic isolates are needed to clarify the taxonomic status of this group.

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.

Molecular identification of Taenia serialis coenurosis in a wild Ethiopian gelada (Theropithecus gelada).

Since morphological identification of a larval Taeniid in geladas (Theropithecus gelada) has produced inconsistent results, genetic information is pivotal for species identification. Nuclear and mitochondrial DNA from a coenurus in a wild gelada were compared to published sequences from multiple Taeniid species, confirming the identification of this parasite as Taenia serialis. A demographic analysis finds age to be a strong predictor of coenuri. Tapeworms rarely employ primates as intermediate hosts, and the presence of T. serialis in a wild gelada population may indicate a substantial ecological shift in this parasite's life cycle.