Subcutaneous cysticercosis due to Taenia crassiceps (Cestoda: Taeniidae) in an imported steppe lemming in Japan.

This study describes a subcutaneous proliferative cysticercosis in a pet steppe lemming, Lagurus lagurus (Rodentia: Cricetidae), bred and imported from Czech Republic into Japan. Numerous metacestodes were collected from the subcutaneous cystic lesion of the left medial thigh. Four surgical removals were coupled with anthelmintic treatment but ended with recurrence. Based on morphological features and mitochondrial DNA sequences, the metacestodes were identified as the larval stage of Taenia crassiceps (Zeder, 1800). This is the first case of infection with larval T. crassiceps in rodents of the genus Lagurus, and becomes the third case of the parasite detected from imported animals in Japan. Related public health concerns are discussed.

Αcute visceral cysticercosis caused by Taenia hydatigena in lambs: ultrasonographic findings.

BACKGROUND: Cysticercosis caused by cysticercus tenuicollis is a metacestode infection that affects several species of ungulates. It is caused by the larval stage of Taenia hydatigena, an intestinal tapeworm in dogs and wild canids. In the intermediate host, the mature cysticerci are usually found in the omentum, mesentery, and peritoneum, and less frequently in the pleura and pericardium. The migrating larvae can be found mostly in the liver parenchyma causing traumatic hepatitis in young animals. Most infections are chronic and asymptomatic, and are diagnosed at the abattoir. The acute form of infection is unusual in sheep and reports of death in lambs are rare. METHODS: In March 2018, fifteen female lambs presented anorexia, weakness, lethargy, and death secondary to acute visceral cysticercosis. Twelve of them underwent hepatic ultrasonography. Examinations were performed on standing or left lateral recumbent animals. RESULTS: Livers of affected animals presented rounded margins and a thickened, irregular and hyperechoic surface. Hepatic parenchyma appeared to be wholly or partially affected by lesions characterized by heterogeneous areas crossed by numerous, irregular, anechoic tracts ranging from 1 to 2 cm in length and 0.1 to 0.2 cm in width. Superficial and intraparenchymal cystic structures were also visualized. The presence of lesions was confirmed by anatomopathological examination, and T. hydatigena cysticerci was identified by morphological and molecular characterization of isolates. CONCLUSIONS: Our results highlighted that hepatic ultrasonography is effective for an intra-vitam diagnosis of acute cysticercosis in lambs.

A comparison of Taenia solium and Taenia hydatigena infection in pigs using serological diagnosis and post-mortem inspection methods in Benoué division, North Cameroon.

The metacestodes of Taenia solium and Taenia hydatigena are the cause of cysticercosis in pigs. T. solium is also responsible of the taeniosis/neurocysticercosis complex in humans, constituting a main cause of epilepsy cases across endemic countries. T. hydatigena is non-zoonotic, but its occurrence in pigs contributes significantly to false positive reactions should genus-species serological methods be used for diagnosis of T. solium porcine cysticercosis. T. hydatigena is often considered not common in pigs in Africa compared to T. solium. On the basis of the evidence that these two cestodes coexist in Cameroon, we examined the viscera of 305 pigs for the identification of the metacestodes of T. hydatigena in Bénoué division, North Region of Cameroon. Tongue, masticatory muscles and heart were sliced for the identification of T. solium cysticerci (TMH dissection test). Twenty seven (8.85%) and 16 (5.24%) pigs were found infected with the metacestodes of T. solium and T. hydatigena, respectively. The difference between the two rates of infection was not statistically significant (P > 0.05). Serum samples were also collected for the evaluation of an inhibition ELISA (i-ELISA) specific to antibodies anti- T. solium or anti-T. hydatigena cysticerci. After incubation of these sera with cyst fluid of T. solium, T. hydatigena, T. multiceps multiceps, T. multiceps gaigeri and T. saginata to eliminate cross-reactions among cestodes parasites, the i-ELISA indicated that 26.56% and 28.52% slaughtered pigs had predominant specific antibodies to cyst fluid of T. solium and T. hydatigena, respectively. Combination of TMH dissection test, i-ELISA and a standard indirect ELISA in a Bayesian simulation approach revealed a true prevalence of 19.27% (0.7-49.27, CI 95%) and 24.85% (5.17-48.34, CI 95%) of porcine cysticercosis due to T. solium and T. hydatigena, respectively. These results indicated that T. hydatigena is as prevalent as T. solium in pigs in the North of Cameroon.

Comparative molecular characterization and phylogenetic analysis of cerebral and non-cerebral coenurosis in Indian goats.

Coenurus cerebralis is the larval stage of Taenia multiceps, which infects the muscles and brain of goats and, to a lesser extent, sheep. The resulting cerebral and non-cerebral infections caused by the larval form (metacestode) of this cestode are commonly known as coenurosis. A weak emaciated carcass of five months old female goat, on necropsy, revealed numerous parasitic cysts (n = 56, grossly visible) in the visceral cavity including heart, diaphragm, thoracic cavity, abdominal cavity and pelvic inlet. A large number of variable sized parasitic cysts were also observed embedded in the pericardium and myocardium causing functional damage to the heart. The parasite caused extensive tissue damage at gross and microscopic levels in the heart including traumatic destruction of the myocardium with degenerative and necrotic changes and infiltration of mononuclear cells. On parasitological examination, the cysts were identified as Coenurus cerebralis, as the scolices had characteristic four suckers and a rostellum with a double crown of hooks. Further confirmation was done using polymerase chain reaction targeting specific ND1 and CO1 genes. Phylogenetic analysis of CO1 and ND1 genes showed a major branch comprising two clades of T. multiceps grouped as separate entities with the first clade showing T. multiceps/Coenurus cerebralis native CIRG strain (cerebral) being placed in proximity to T. multiceps/Coenurus cerebralis CIRG strain (non-cerebral/visceral) compared to the Chinese strains of T. multiceps. The phylogenetic analysis of ND1 and CO1 genes of C. cerebralis of cerebral and non-cerebral isolates revealed close proximity but expressed in two different disease forms (i.e., visceral coenurosis and neural coenurosis) which indicated that they were very close divergent from a common ancestor. On the basis of the observations it was concluded that goat died due to cardiac dysfunction resulting from severe systemic infection of metacestode of T. multiceps was closely related to isolate that caused neural coenurosis in another goat. Based on the sequencing analysis and phylogenetic information, the possible differences in the clinical manifestation (neural or visceral) could be attributed to the pathogenesis.

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.

High mortality associated with tapeworm parasitism in geladas (Theropithecus gelada) in the Simien Mountains National Park, Ethiopia.

Despite increasing appreciation for parasitism as an important component of primate ecology and evolution, surprisingly few studies have demonstrated the costs of helminth parasitism in primates. Detecting parasite-related costs in primates is particularly difficult because it requires detailed, long-term data on individual host reproductive success, survival, and parasitism. The identification of the larval tapeworm Taenia serialis in geladas under intensive long-term study in the Ethiopian Highlands (Nguyen et al. [2015] American Journal of Primatology, 77:579-594; Schneider-Crease et al. [2013] Veterinary Parasitology 198:240-243) provides an opportunity to examine how an endemic parasite impacts host reproductive success and survival. We used survival analyses to assess the mortality risk associated with protuberant larval cysts characteristic of T. serialis using a decade of data from a gelada population in the Simien Mountains National Park (SMNP), Ethiopia. We demonstrated strikingly high mortality associated with T. serialis cysts in adult females, particularly for younger adults. The estimated effect of cysts on male mortality was similar, although the effect was not statistically significant, likely owing to the smaller sample size. Additionally, the offspring of mothers with cysts experienced increased mortality, which was driven almost entirely by maternal death. Mothers with cysts had such high mortality that they rarely completed an interbirth interval. Comparison with a study of this parasite in another gelada population on the Guassa Plateau (Nguyen et al. [2015] American Journal of Primatology, 77:579-594) revealed lower cyst prevalence in the SMNP and similar cyst-associated mortality. However, many more females with cysts completed interbirth intervals at Guassa than in the SMNP, suggesting that T. serialis cysts may kill hosts more rapidly in the SMNP. Our results point toward the underlying causes of individual and population-level heterogeneity in T. serialis-associated mortality as important areas for future research.

Epidemiological Survey and Phylogenetic Characterization of Cysticercus tenuicollis Isolated from Tibetan Pigs in Tibet, China.

Cysticercus tenuicollis, commonly known as "water bell," is a larva of Taenia hydatigena, which is the most significant parasite of pigs. However, until now very few information is available regarding the prevalence and genetic characterization of the Cysticercus tenuicollis in Tibetan pigs. Therefore, the aim of this study was to investigate the prevalence and phylogenetic analysis of Cysticercus tenuicollis in Tibetan pigs. For this purpose, the COX2 gene of Cysticercus tenuicollis was amplified and sequenced for the first time in Tibetan pigs. The overall prevalence of Cysticercus tenuicollis was 43.93% in Tibetan pigs, with further distribution of 42.86% in 2014 and 45.35% in 2015. In Tibetan male and female pigs, the prevalence of Cysticercus tenuicollis was 43.39% and 44.56%, respectively. The prevalence of Cysticercus tenuicollis in different growing stages (juveniles, subadults, and adults) varied from 30.20% to 63.79%. The phylogenetic analysis of the Cysticercus tenuicollis isolates showed very close resemblance to 16 reference strains, isolates from Gansu, Hunan, and Sichuan provinces of China. To the best of our knowledge, this is the first report on the prevalence and genetic characterization of Cysticercus tenuicollis derived from Tibetan pigs. The data of present study provides baseline information for controlling cysticerci infections in pigs in Tibetan Plateau, China.

Extraintestinal Helminth Infection Limits Pathology and Proinflammatory Cytokine Expression during DSS-Induced Ulcerative Colitis: A Role for Alternatively Activated Macrophages and Prostaglandins.

Chronic inflammation of the intestinal mucosa is characteristic of inflammatory bowel diseases such as ulcerative colitis and Crohn's disease. Helminth parasites have developed immunomodulatory strategies that may impact the outcome of several inflammatory diseases. Therefore, we investigated whether Taenia crassiceps infection is able to decrease the inflammatory effects of dextran sulfate sodium- (DSS-) induced ulcerative colitis in BALB/c and C57BL/6 mice. Preinfection significantly reduced the manifestations of DSS-induced colitis, as weight loss and shortened colon length, and decreased the disease activity index independently of the genetic background of the mice. Taenia infection decreased systemic levels of proinflammatory cytokines while increasing levels of IL-4 and IL-10, and the inflammatory infiltrate into the colon was also markedly reduced. RT-PCR assays from colon showed that T. crassiceps-infected mice displayed increased expression of Arginase-1 but decreased expression of iNOS compared to DSS-treated uninfected mice. The percentages of T regulatory cells were not increased. The adoptive transfer of alternatively activated macrophages (AAMФs) from infected mice into mice with DSS-induced colitis reduced the severity of colon inflammation. Administration of indomethacin abrogated the anticolitic effect of Taenia. Thus, T. crassiceps infection limits the pathology of ulcerative colitis by suppressing inflammatory responses mechanistically associated with AAMФs and prostaglandins.

Imaging in neurocysticercosis.

Neurocysticercosis is a parasitic neurological infection caused by the ingestion of larvae from the adult tapeworm Taenia solium. We describe a man who presented with generalised tonic-clonic seizures. He had been previously diagnosed with epilepsy in Malawi, where he had emigrated from 2 years before this episode. An MRI was performed to further investigate the cause of his seizures, as no previous imaging had been performed. His initial MRI showed multiple characteristic cystic lesions in keeping with neurocysticercosis.

The present situation of human taeniases and cysticercosis in Asia.

Three human Taenia species, Taenia solium, Taenia saginata, and Taenia asiatica, are endemic in rural regions of Asia, with these species sympatrically distributed in parts of Thailand and China. The pork tapeworm, T. solium, is the most pathogenic to humans, causing cysticercosis and neurocysticercosis (NCC). Due to its public health impact, T. solium taeniasis/cysticercosis is one of 17 neglected tropical diseases (NTDs) prioritized by the World Health Organization. In this review, the current status of taeniasis and NCC in several Asian countries will be presented as will possible prevention and control strategies. Among the known T. solium endemic areas in Asia, Bali, Indonesia is of high importance due to the risk of tourists becoming infected. Therefore, special attention will be given to ongoing control initiatives in Bali.

Neurocysticercosis in infants and toddlers: report of seven cases and review of published patients.

Neurocysticercosis in infants and toddlers has received little attention in the literature, and little is known about the mechanisms of disease acquisition and clinical forms of presentation of the disease in this age group. All patients aged ≤3 years with neurocysticercosis evaluated at Hospital-Clínica Kennedy, Guayaquil, over a 22-year period were included in this study. Their household contacts were screened to detect Taenia solium carriers, which may represent the source of infection. A literature search on neurocysticercosis in infants and toddlers was also performed to compare personal cases with those described elsewhere. A total of 25 infants and toddlers with neurocysticercosis were included (seven from our institution and 18 from the literature). All patients had seizures as the primary manifestation of the disease, and neuroimaging studies showed one or two parenchymal brain cysticerci in the colloidal stage in 88% of patients. The source of infection was investigated in 11 houses, including the seven households of the present series, and only four of the 18 reported in the literature. A Taenia carrier was found in five (45%) of these households, including three from the present series and two from the literature. A sizable proportion of infants and toddlers with neurocysticercosis have been infected at home. Compulsory search of Taenia carriers among household contacts will allow the detection of the potential source of infection and will reduce further spread of the disease. The search must not be limited to family members, but also extended to domestic employees who are in daily contact with the children.

State of the art of Taenia solium as compared to Taenia asiatica.

Three species of tapeworms infect humans in their adult stage (Taenia solium, Taenia saginata and Taenia asiatica). The 3 are flat, opaque white or yellowish, and exceptional long segmented parasites, measuring 1 to 12 m in their adult stage. In this review, the development of the knowledge regarding the first species, mainly focused on understanding how the larval stage or cysticercus is transmitted to humans, is described. The second species is a cosmopolitan parasite that only causes taeniosis and not cysticercosis; therefore, it will not be included. Information on the third species, which is presently being produced, since this species was recognized as such only at the end of the 20th century, will be discussed at the end of this review.

Taenia asiatica: the most neglected human Taenia and the possibility of cysticercosis.

Not only Taenia solium and Taenia saginata, but also Taenia asiatica infects humans. The last species is not included in the evaluation of the specificity of the immunodiagnostic techniques for taeniasis/cysticercosis. There is currently no specific immunodiagnostic method for T. asiatica available. Therefore, due to the fact that molecular techniques (the only tool to distinguish the 3 Taenia species) are normally not employed in routine diagnostic methods, the 2 questions concerning T. asiatica (its definite geographic distribution and its ability to cause human cysticercosis), remain open, turning T. asiatica into the most neglected agent of human taeniasis-cysticercosis.

Sex-associated expression of co-stimulatory molecules CD80, CD86, and accessory molecules, PDL-1, PDL-2 and MHC-II, in F480+ macrophages during murine cysticercosis.

Macrophages are critically involved in the interaction between T. crassiceps and the murine host immune system. Also, a strong gender-associated susceptibility to murine cysticercosis has been reported. Here, we examined the sex-associated expression of molecules MHC-II, CD80, CD86, PD-L1, and PD-L2 on peritoneal F4/80(hi) macrophages of BALB/c mice infected with Taenia crassiceps. Peritoneal macrophages from both sexes of mice were exposed to T. crassiceps total extract (TcEx). BALB/c Females mice recruit higher number of macrophages to the peritoneum. Macrophages from infected animals show increased expression of PDL2 and CD80 that was dependent from the sex of the host. These findings suggest that macrophage recruitment at early time points during T. crassiceps infection is a possible mechanism that underlies the differential sex-associated susceptibility displayed by the mouse gender.

A review of cases of human cysticercosis in Canada.

OBJECTIVE: Review of human cysticercosis in Canada, to estimate the magnitude of the disease and to describe the pattern of disease expression in this country. METHODS: MEDLINE and manual search of case reports and case series of patients with cysticercosis diagnosed in Canada. Abstracted data included year of diagnosis, citizenship status, clinical manifestations, and form of cysticercosis. FINDINGS: A total of 21 articles reporting 60 patients were found. Forty (67%) of these patients were diagnosed in the past two decades. Most cases came from Ontario (n=43) and Quebec (n=14). Immigrants accounted for 96% of the 28 cases in whom citizenship information was available. Neurocysticercosis was observed in 55 patients, and isolated compromise of striated muscles in the remaining five. Seizures was the primary or sole manifestation of the disease in 72% of patients, and most of them had parenchymal brain cysticerci (either viable cysts or calcifications). Two of seven patients were positive for Taenia eggs. In no case were household contacts of the patients investigated for taeniasis. CONCLUSIONS: An increasing number of patients with cysticercosis have been reported from Canada in the past two decades, suggesting that the prevalence of this parasitic disease may be on the rise. While most cases occur in immigrants, it is possible that at least some of these patients had acquired the disease in Canada.

TLR2 mediates immunity to experimental cysticercosis.

Information concerning TLR-mediated antigen recognition and regulation of immune responses during helminth infections is scarce. TLR2 is a key molecule required for innate immunity and is involved in the recognition of a wide range of viruses, bacteria, fungi and parasites. Here, we evaluated the role of TLR2 in a Taenia crassiceps cysticercosis model. We compared the course of T. crassiceps infection in C57BL/6 TLR2 knockout mice (TLR2⁻/⁻) with that in wild type C57BL/6 (TLR2⁺/⁺) mice. In addition, we assessed serum antibody and cytokine profiles, splenic cellular responses and cytokine profiles and the recruitment of alternatively activated macrophages (AAMφs) to the site of the infection. Unlike wild type mice, TLR2⁻/⁻ mice failed to produce significant levels of inflammatory cytokines in either the serum or the spleen during the first two weeks of Taenia infection. TLR2⁻/⁻ mice developed a Th2-dominant immune response, whereas TLR2⁺/⁺ mice developed a Th1-dominant immune response after Taenia infection. The insufficient production of inflammatory cytokines at early time points and the lack of Th1-dominant adaptive immunity in TLR2⁻/⁻ mice were associated with significantly elevated parasite burdens; in contrast, TLR2⁺/⁺ mice were resistant to infection. Furthermore, increased recruitment of AAMφs expressing PD-L1, PD-L2, OX40L and mannose receptor was observed in TLR2⁻/⁻ mice. Collectively, these findings indicate that TLR2-dependent signaling pathways are involved in the recognition of T. crassiceps and in the subsequent activation of the innate immune system and production of inflammatory cytokines, which appear to be essential to limit infection during experimental cysticercosis.