Description and life-cycle of Taenia lynciscapreoli sp. n. (Cestoda, Cyclophyllidea)

Ecological and molecular associations between neotropical wild felids and Taenia (Cestoda: Taeniidae) in the Atlantic Forest: a new report for Taenia omissa

Ecological associations between wild felids and parasites from the Taeniidae family are related to predator-prey interactions, where felids act as definitive hosts while their prey, herbivores and/or omnivores, act as intermediate hosts. In the Atlantic Forest, six neotropical felid species coexist in sympatry, but the ecological parasite-host interactions remain poorly studied. Taenia omissa is a tapeworm that parasitizes cougars (Puma concolor) as its only definitive host and their ungulate prey as intermediate hosts. The aim of this study was to identify tapeworms present in road-killed fauna using both molecular and morphological characteristics and their predator-prey relationship. Adult tapeworms found in a cougar, a jaguarundi (Herpailurus yagouaroundi), and two ocelots (Leopardus pardalis); and metacestodes found in a red brocket deer (Mazama americana) and a wild guinea pig (Cavia aperea) were analyzed. Through morphological analysis of rostellar hooks and molecular analysis of the mitochondrial genetic marker cox1, Taenia omissa adult individuals were identified in the cougar, and metacestodes in the red brocket deer, proving the existence of a full host-parasite life cycle in the Atlantic Forest region. This new report reveals the southernmost record of T. omissa and broadens its geographic distribution. In addition, isolates of the Taenia genus divergent from those described so far in molecular databases were reported and suggested a wild cycle that involves the jaguarundi and agouti (Dasyprocta asarae) as definitive and intermediate hosts, respectively. These results highlight the complexity of the tapeworm population in the region and the need to study it with both morphological and molecular approaches.

Taenia lynciscapreoli in semi-domesticated reindeer (Rangifer tarandus tarandus, L.) in Sweden

We report here Taenia lynciscapreoli metacestode from the lung lobe of a semi-domesticated reindeer (Rangifer tarandus tarandus). The specimen was detected within a development project concerning remote post mortem inspection at a reindeer abattoir in Sweden. Post mortem inspection was performed according to a routine on-site official meat inspection protocol. The species identification to T. lynciscapreoli was confirmed based on the DNA extracted from the metacestode, which was analysed by sequencing of the cytochrome c oxidase subunit 1. Firstly, our finding shows that semi-domesticated reindeer in addition to several other cervids can act as an additional intermediate host for T. lynciscapreoli. Secondly, it further confirms that this parasite is more widely distributed on the Scandinavian peninsula than what has previously been shown. This is in line with a previous molecular finding of adult T. lynciscapreoli from the Eurasian lynx (Lynx lynx) in Sweden and demonstrates that new intermediate host can be detected. Whether the present finding can be regarded as accidental or have created opportunities for an expansion throughout the northernmost Scandinavian Peninsula remains to be seen.

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Semi-domesticated reindeer can act as the intermediate host for T. lynciscapreoli.

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T. lynciscapreoli is more widely distributed than previously shown.

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The impact on reindeer welfare remains unknown.

High Toxocara cati prevalence in wild, free-ranging Eurasian lynx (Lynx lynx) in Finland, 1999–2015

In Finland, free-ranging Eurasian lynx (Lynx lynx) population has grown from 30 to 40 individuals to 2800 individuals since the species became partly protected in 1962. Changes in host population size are known to have an impact on host-parasite dynamics, and the Eurasian lynx population in Finland provides a unique opportunity for studying the potential effects of dramatic population increase and expansion of a solitary apex predator on their parasite prevalence and abundance. Toxocara cati is a zoonotic gastrointestinal parasite infecting domestic cats and wild felids worldwide. We studied T. cati infection prevalence and worm burden in 2756 Eurasian lynx individuals from Finland, covering the years 1999–2015. Toxocara cati worms that had been collected from intestinal contents were identified based on morphology. We performed regression analyses to investigate possible associations of age, sex, and host population density with T. cati infection. We found T. cati from 2324 (84.3%, 95% confidence interval 82.9–86.0) of the examined lynx. Each year, the infection prevalence was higher than 75% and not density dependent. The parasites were strongly aggregated, with older individuals harboring fewer T. cati than younger ones did. Old females aged 9–15 years had higher T. cati abundance than males of the same age group. Our results indicate that T. cati was a common and abundant parasite of Eurasian lynx throughout the study period, regardless of the changing population size and density.

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84% of 2756 Eurasian lynx (Lynx lynx) from Finland had Toxocara cati infection.

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The prevalence was high throughout 1999–2015, while lynx population size tripled.

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Old female lynx had significantly higher Toxocara cati abundance than old males.

Advances in the treatment, diagnosis, control and scientific understanding of taeniid cestode parasite infections over the past 50 years

In the past 50 years, enormous progress has been made in the diagnosis, treatment and control of taeniid cestode infections/diseases and in the scientific understanding thereof. Most interest in this group of parasites stems from the serious diseases that they cause in humans. It is through this lens that we summarize here the most important breakthroughs that have made a difference to the treatment of human diseases caused by these parasites, reduction in transmission of the taeniid species associated with human disease, or understanding of the parasites' biology likely to impact diagnosis or treatment in the foreseeable future. Key topics discussed are the introduction of anti-cestode drugs, including benzimidazoles and praziquantel, and the development of new imaging modalities that have transformed the diagnosis and post-treatment monitoring of human echinococcoses and neurocysticercosis. The availability of new anti-cestode drugs for use in dogs and a detailed understanding of the transmission dynamics of Echinococcus granulosus sensu lato have underpinned successful programs that have eliminated cystic echinococcosis in some areas of the world and greatly reduced the incidence of infection in others. Despite these successes, cystic and alveolar echinococcosis and neurocysticercosis continue to be prevalent in many parts of the world, requiring new or renewed efforts to prevent the associated taeniid infections. Major advances made in the development of practical vaccines against E. granulosus and Taenia solium will hopefully assist in this endeavour, as might the understanding of the parasites' biology that have come from an elucidation of the nuclear genomes of each of the most important taeniid species causing human diseases.

Taenia laticollis and a potentially novel Taenia species from the Eurasian lynx (Lynx) in Northwestern China

The Eurasian lynx (Lynx) is a medium-sized wild cat species distributed throughout Eurasia. There has been no report on Taenia species (Cestoda: Cyclophyllidea) infecting this felid in China. In this study, 24 tapeworms were found in two Eurasian lynxes (#1 and #2) in Xinjiang Uygur Autonomous Region (XUAR), northwestern China. Based on the number, measurements and the shape of rostellar hooks, these tapeworms belong to two Taenia species. According to the number (n = 32) and length (185-194 μm) of small hooks, the first Taenia species (n = 1, found in #2 lynx) was identified as Taenia laticollis. Phylogenetically, this species was clustered with T. laticollis genotype C (JX860623) based on its cytochrome c oxidase subunit 1 (cox1) and 16S rDNA sequences. The second Taenia species (n = 23, provisionally named as "Taenia sp.") may represent a potentially novel tapeworm species, because of its obvious differences in the shape and lengths (174-182 μm, 98-113 μm) of large and small rostellar hooks in comparison with ten taxonomically related species. Molecular and phylogenetic analyses of the cox1 gene revealed that "Taenia sp." has the highest rate of sequence identity (92.93%, 368/396 bp) with Taenia hydatigena reported from sheep (Ovis aries) in Slovakia. To sum up, a potentially novel tapeworm species, "Taenia sp.", is found in Eurasian lynx. In addition, T. laticollis was found for the first time in China.

Paleoparasitology and archaeoparasitology in Iran: A retrospective in differential diagnosis

OBJECTIVE

This paper reviews paleo- and archaeoparasitology publications to date, from Iran. The primary focus is the importance of differential diagnosis and the crucial role of interdisciplinary collaborations among parasitologists and other specialists.

METHODS

All relevant articles and theses published in Iran through October 2020 are included and evaluated, with particular emphasis on the diagnostic process.

RESULTS

Archaeoparasitic studies in Iran have identified a number of parasites that provide insight into the past. Misidentification, however, due to incomplete differential diagnosis, remains an issue, as does incomplete description and problematic images.

CONCLUSIONS

Identification of paleoparasites to the species level must be supported with accurate morphology and morphometry. Rigorous differential diagnosis is essential. Caution must be exercised when interpreting observations of ova recovered from coprolites. In these instances, precise identification of host animals and aligning parasite ranges with host specificity is critical. The possibility of incidental parasite presence must be evaluated, including non-specificity of parasite tropisms, transport hosting, or contamination. Lastly, differential diagnosis must include consideration of intentional consumption of parasites. Thus, parasitological findings must be placed in geographical, historical, and cultural contexts.

SIGNIFICANCE

Archaeoparasitological research in Iran has elucidated the presence of faunal and human disease in the past and has, through this reevaluation of the published works, contributed to precise description and diagnosis of ova of roundworms, tapeworms, thorny-headed worms, and recognition of larval stages of tapeworms in recovered remains of mites.

First Report on Molecular Characterization of Taenia multiceps Isolates From Sheep and Goats in Faisalabad, Pakistan

Coenurus cerebralis is the larval stage of Taenia multiceps commonly found in the brain (cerebral form), intramuscular and subcutaneous tissues (non-cerebral form) of ungulates. Globally, few reports exist on the molecular characterization and genetic diversity of C. cerebralis with none available for Pakistan. The current study molecularly characterized 12 C. cerebralis isolates surgically recovered from sheep (n = 4) and goats (n = 8) from a total of 3,040 small ruminants using a portion of the cytochrome c oxidase subunit 1 (cox1) mitochondrial (mt) gene. NCBI BLAST search confirmed the identity of each isolate. A high haplotype and a low nucleotide diversity with three haplotypes from the 12 isolates were observed. The findings suggest the existence of unique haplotypes of C. cerebralis in Pakistan. The negative value of Tajima's D and the positive value of Fu's Fs were inconsistent with population expansion, however, the sample size was small. Bayesian phylogeny revealed that all Pakistani isolates alongside the Chinese sequences (obtained from GenBank) constituted a cluster while sequences from other regions constituted another cluster. This is the first molecular study to determine the genetic diversity of C. cerebralis in Pakistan and serves as a foundation for prospective studies on the prevalence and population structure of C. cerebralis in the country. Furthermore, in this study, we amplified only a partial segment of the cox1 gene from a limited sample size. This could have implications on the interpretation of the actual population structure in reality. Thus, we recommend future studies to consider a larger sample size in a massive epidemiological survey for further insights.

Diversity of Taenia and Hydatigera (Cestoda: Taeniidae) in domestic dogs in Kenya

Taenia species of domestic dogs can cause cysticercosis and coenurosis in a wide range of intermediate hosts including humans. Most taeniids of dogs are globally distributed, but some wildlife-transmitted species can be specific for certain regions. Generally, little information exists on the species composition and frequency in most regions of the world, which impairs risk assessment and control strategies. This study determined the range of taeniid species in dogs in four widely spaced areas of Kenya by genetic identification of eggs in faeces collected from the environment. Individual taeniid eggs were characterised by nested polymerase chain reaction of NADH dehydrogenase subunit 1 and cytochrome C oxidase 1 genes, restriction fragment length polymorphism and partial sequencing. Overall 79/1621 (4.9%) faecal samples contained eggs of Taenia or Hydatigera (8.0% in Turkana, 4.8% in Isiolo, 3.8% in Maasai Mara and 1.3% in Meru). Taenia hydatigena and T. multiceps were the most frequent, found in 36 and 15 samples, respectively. Other eggs found in the faeces belonged to T. serialis (sensu lato), T. madoquae (the first record in domestic dogs), T. ovis, T. saginata and Hydatigera taeniaeformis. Polymorphism of nad1 sequences revealed 22 and 8 haplotypes of T. hydatigena and T. multiceps, respectively. The results show the involvement of dogs in both domestic and sylvatic transmission cycles. In addition to the species range, this study provides data on the intraspecific diversity of T. hydatigena and T. multiceps in Kenya, which will serve as baseline information for further studies into cysticercosis and coenurosis in livestock and humans in the region.

The morphological and molecular identification of the tapeworm, Taenia lynciscapreoli, in intermediate and definitive hosts in Poland

The tapeworm Taenia lynciscapreoli is a new species of the genus Taenia described in 2016, and which remains poorly understood. The aim of the present study is to extend current knowledge regarding its, morphology and genome. Biological material was analysed from three species of wild animals: Eurasian lynx (Lynx lynx), roe deer (Capreolus capreolus) and moose (Alces alces). Twenty-four adult tapeworms and four larvae were obtained from Eurasian lynx and roe deer respectively; none were detected in the studied moose. On the basis of morphometric (hooks measurements) and molecular analysis (partial 780 bp cox 1 gene sequences), the analysed tapeworm was identified as Taenia lynciscapreoli species. The phylogenetic analysis of the obtained sequences identified two haplotypes. The obtained findings can be used to supplement the species description. To our knowledge this is the first morphological and molecular identification of T. lynciscapreoli in roe deer, intermediate host, in Poland.

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Study is molecular and morphological identification of T. lynciscapreoli in Poland.

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78 animals from three species were examined: roe deer (71), moose (6) and lynx (1).

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28 parasites specimens were analysed: larvae (4), adult (24).

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This is the first identification of T. lynciscapreoli in roe deer in Poland.

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New description of the tapeworm should include that the number of hooks is 30–38.

Update of the helminth fauna in Eurasian lynx (Lynx lynx) in Poland

The Eurasian lynx (Lynx lynx) is a strictly protected species of large carnivore in Poland. It inhabits forest complexes in north-eastern Poland and the Carpathian region in southern Poland. The status of the lynx within Poland requires special attention because its range decreased between 1980 and 2001 and has not yet recovered. One of the factors negatively affecting lynx populations is diseases, particularly parasites. The helminth fauna of the Eurasian lynx is not fully known in Poland. Previous coprological studies revealed that Polish lynx have been infected with seven species of nematodes, three species of cestodes, and one species of trematode. In this study, we present new data based on examination of opportunistically collected lynx carcasses. The aim of the study was to complement data on the helminth fauna of Eurasian lynx inhabiting Poland based on morphological and molecular analysis of parasites. Four species of cestodes—Taenia lynciscapreoli, Mesocestoides lineatus, Spirometra sp., and Taenia krabbei—were found for the first time in Eurasian lynx from Poland and three previously reported species of nematodes—Ancylostoma tubaeforme, Toxascaris leonina, and Toxocara cati—were confirmed. Larvae of Trichinella britovi were also detected in Eurasian lynx in Poland for the first time.

Genetic characterization of three mitochondrial gene sequences of goat/sheep-derived coenurus cerebralis and cysticercus tenuicollis isolates in Inner Mongolia, China

Taenia multiceps and Taenia hydatigena are widely distributed tapeworms of canids. Due to a lack of genetic information on these two parasites in China, in this study we analyzed six coenurus cerebralis and two cysticercus tenuicollis cysts from goats or sheep in Inner Mongolia, northern China by amplifying three mitochondrial genes (cox1, nad4, and cytb). Two haplotypes were obtained at each locus for either of the two Taenia cestode species, with ten nucleotide sequences being novel. The degrees of genetic variations were 1.18%, 0.61% and 0.52% for coenurus cerebralis, and 0.24%, 0.46% and 0.35% for cysticercus tenuicollis at the cox1, nad4 and cytb loci, respectively. This is the first molecular description of animal-derived metacestodes of T. multiceps and T. hydatigena in Inner Mongolia, China. Novel nucleotide sequences might reflect endemic genetic characterization of the two cestodes. The present data are useful to explore the biological and epidemiological significance of intra-specific variations within both Taenia cestodes.

The role of chewing lice (Phthiraptera: Philopteridae) as intermediate hosts in the transmission of Hymenolepis microps (Cestoda: Cyclophyllidea) from the willow ptarmigan Lagopus lagopus (Aves: Tetraonidae)

The cestode Hymenolepis microps is an intestinal parasite of tetraonid birds, including the willow ptarmigan (Lagopus lagopus). This parasite is able to maintain a high prevalence and intensity throughout the year, even in a subarctic environment in bird populations with relatively low host densities, indicating effective transmission routes. Willow ptarmigan consume mainly vegetal material and active consumption of invertebrates is confined to the first two or three weeks of life. Ptarmigan are infected by different species of ectoparasites, of which two species of feather lice, Lagopoecus affinis and Goniodes lagopi, are the most abundant. In this study, we explored the hypothesis that feather lice may be suitable intermediate hosts for H. microps. We applied histological techniques and light microscopy to investigate lice for the presence of larval cestode stages (cysticercoids). We found 12 cysticercoid-like structures inside chewing lice collected on L. lagopus hosts harbouring H. microps. In addition, a polymerase chain reaction (PCR) screening of Ischnocera lice DNA, targeting the 18S rRNA gene of the cestode, showed positive results for two different short fragments of the 18S rRNA gene of H. microps which were sequenced from lice collected on birds. Both independent lines of evidence support the hypothesis that Ischnocera lice might be suitable intermediate hosts in the life cycle of H. microps in L. lagopus.