SYSTEMATICS OF MESOCESTOIDES (CESTODA: MESOCESTOIDIDAE): EVALUATION OF MOLECULAR AND MORPHOLOGICAL VARIATION AMONG ISOLATES

Wood mouse (Apodemus sylvaticus L.) as intermediate host for Mesocestoides canislagopodis (Rudolphi, 1810) (Krabbe 1865) in Iceland

Mesocestoides canislagopodis is a common parasite of the arctic fox (Vulpes lagopus) in Iceland. In the past, household dogs (Canis familiaris) and cats (Felis catus) were also reported in Iceland to be infected. Recently, scolices of a non-maturing Mesocestoides sp. were detected in the intestines of the gyrfalcon (Falco rusticolus), and tetrathyridia were isolated in the body cavity of rock ptarmigan (Lagopus muta) and subsequently described. All stages were confirmed, using both morphological and molecular methods, to belong to the same species, M. canislagopodis. In the present study, post-mortem examination of wood mice (Apodemus sylvaticus), sampled in autumn 2014 on a farm in Northeast Iceland, revealed the presence of tetrathyridia in the peritoneal cavity and in the liver. Most tetrathyridia in the peritoneal cavity were free, but some were encapsulated in a thin connective tissue stroma and loosely attached to the inner organs. They appear as whitish, heart-shaped, flattened, unsegmented bodies with a slightly pointed posterior end. In the liver, tetrathyridia were seen as pale-tanned nodules embedded in the parenchyma. Comparative molecular analysis, both at the generic level (D1 domain LSU ribosomal DNA), and at the specific level (cytochrome c oxidase subunit I (cox1) and 12S mitochondrial DNA), revealed that the tetrathyridia belonged to M. canislagopodis. A. sylvaticus represents a new second intermediate host record in Iceland, and the first description of a rodent as intermediate host for this species, thus participating in the life cycle of the parasite.

Cryptic species Hydatigera kamiyai and other taeniid metacestodes in the populations of small mammals in Serbia

BACKGROUND

Hydatigera (Cestoda: Taeniidae) is a recently resurrected genus with the description of a new species, Hydatigera kamiyai, a cryptic entity within the Hydatigera taeniaeformis species complex. Rodents are intermediate hosts and correct taxonomic identification of H. taeniaeformis sensu lato (s.l.) species is difficult without the use of molecular methods. The aim of this study was to identify and explore the genetic diversity of Hydatigera and other taeniid species.

METHODS

Ten different small mammals species (856 individuals) (Rattus rattus, three Apodemus, three Arvicolinae and three Soricidae species) were examined from 2013 to 2023. Captured animals were visually examined for cysts and visible lesions. Two markers were used for amplification and sequencing: cox1 and 12S rDNA.

RESULTS

Molecular analysis of cysts and visible lesions revealed four taeniid species: Hydatigera kamiyai, H. taeniaeformis sensu stricto (s.s.), Taenia martis and T. crassiceps. Hydatigera kamiyai was found in Apodemus flavicollis, A. agrarius, Microtus arvalis and Crocidrua leucodon, while H. taeniaeformis s.s. is registered in R. rattus. Hydatigera kamiyai cox1 sequences clustered with European populations and showed at least 25 nucleotid differences compared to Asian, African, Australian and one of our isolates of H. taeniaeformis s.s acquired from a rat, followed by large sequence distances (9.4% to 12.9%), indicating clear molecular distinction of two species.

CONCLUSIONS

This is one of the few mitochondrial gene-based studies performed after the description of cryptic entities within the Hydatigera taeniaeformis s.l. complex and represents a valuable contribution to understanding of genetic diversity, host suitability and geographic distribution of these tapeworm species. Also, our study provides an important basis of molecular data from this part of Europe for further studies. We emphasize the importance of additional studies of intermediate hosts, especially rats from Europe and Apodemus spp. and voles from Asia and Africa.

Intestinal endoparasitism in wild cat (Felis silvestris) from Banat area (Romania)

The wild cat (Felis silvestris), spread in Romania from the Danube Delta to the mountain range is present in the Banat area, on the hunting ground that can be contaminated with different stage developmental forms of parasites, some of them having real zoonotic potential. The wild cat is an animal protected by the Romanian law of protection animals. Coprological samples from 88 wild cats from 16 hunting grounds, as well as the gastrointestinal tract collected from six wild cats cadavers and the molecular characterization of the cestodes identified in their intestines, allowed us to establish intestinal parasitic fauna. During coprological examination Isospora oocysts, tapeworm eggs, eggs of Toxocara cati, Ancylostoma spp. and Capillaria spp were found. At the same time, the form of genera Mesocestoides, Taenia, Toxocara/Toxascaris and Ancylostoma were identified at necropsy. Further polymerase chain reaction (PCR) identification revealed the species of Taenia taenieformis, and Mesocestoides litteratus, the latter providing a zoonotic potential. This study, the first in the western part of the country (Banat area, Timis County), provides information about the parasitic fauna of wild cats and underlines the importance of the human contamination risk.

Distribution and prevalence of Taenia hydatigena, Taenia multiceps, and Mesocestoides spp. in Mongolian sheepdogs

Gastrointestinal parasite infections in livestock and companion animals in Mongolia have not been investigated sufficiently. This study aimed to determine the prevalence of cyclophyllid cestodes (Taeniidae and Mesocestoididae) in Mongolian sheepdogs using copro-DNA analysis. Sheepdog fecal samples (n = 1242) were collected from five ecological zones (mountain taiga, forest-steppe, steppe, desert-steppe, and desert) and four geographical regions (Western, Khangai, Central, and Eastern) within 20 of the country's 21 provinces. Among the 1242 samples, 201 (16.2%) tested positive for mitochondrial cytochrome c oxidase subunit 1 (cox1) and ribosomal 12S rRNA encoding genes of cyclophyllid cestodes. Prevalence in the mountain taiga, forest-steppe, steppe, desert-steppe, and desert zones was 29.2%, 15.4%, 15.1%, 20.1%, and 9.1%, respectively. Prevalence in the Western, Khangai, Central, and Eastern regions was 19.9%, 18.6%, 12.1%, and 12.8%, respectively. Taenia hydatigena, Taenia multiceps, and two Mesocestoides species (Mesocestoides sp.1 and Mesocestoides sp.2) were identified. T. hydatigena was found in the samples from all 20 provinces (all five zones and four regions), while T. multiceps was detected in the samples from 19 provinces (all five zones and four regions). Mesocestoides sp.1 infection was detected in the samples from all zones (except desert) and regions; it was detected in 14 provinces. Mesocestoides sp.2 infection was detected in the samples from all zones (except mountain taiga) and regions and found in seven provinces. Cyclophyllidea infection in sheepdogs is highly prevalent across Mongolia, representing a zoonotic risk. Implementation of a surveillance program for sheepdogs and their owners, and the wild animals in all ecological zones should be considered. In addition, control measures, including public awareness campaigns, especially for sheepdog owners, and periodic deworming of sheepdogs are warranted.

Intestinal helminth infections in the golden jackal (Canis aureus L.) from Vojvodina: Hotspot area of multilocular echinococcosis in Serbia

In the present study, 64 golden jackals were examined for intestinal helminths in three regions of Vojvodina, Serbia. Among the examined jackals 57.8% were infected with at least one parasite species. Using the intestinal scraping technique (SCT), eight species of intestinal helminths were found: Alaria alata (7.8%), Toxascaris leonina (9.4%), Toxocara canis (4.7%), Uncinaria stenocephala (20.3%), Echinococcus multilocularis (14.1%), Mesocestoides sp. (42.2%), Taenia pisiformis, and Taenia hydatigena (the overall prevalence of Taenia infection was 6.3%). To the best of our knowledge, this is the first report of T. leonina in jackals from Serbia. In comparison with the SCT results, coprological tests were less sensitive and specific for parasite identification, as only two nematode species (T. leonina and T. canis) as well as ancylostomatid and taeniid eggs were identified. The total prevalence of intestinal helminths was higher in males (71.9% males, 45% females), but the difference was not statistically significant (χ 2 = 3.76; P = 0.052). Co-infection with two species of intestinal helminths was found in 35% of the examined golden jackal individuals, three-species co-infection was demonstrated in 21.6%, whereas four-species co-infection was detected in 2.7% of the golden jackals examined. Echinococcus multilocularis has previously been recorded in jackals and foxes in Serbia, but only in Vojvodina. Our results corroborate the findings of previous studies, and indicate that the Vojvodina Province, more specifically the Srem region, is probably a high-risk area for E. multilocularis transmission to humans.

Global prevalence of Mesocestoides infections in animals - A systematic review and meta-analysis

Mesocestoides spp. are zoonotic cestodes found as adults in carnivorous domestic and wild definitive hosts and as metacestodes in several taxa of intermediate hosts. Although several regional studies record its occurrence in different host populations, the global prevalence and patterns of occurrence of Mesocestoides spp. are not fully understood. The objective of this study was to conduct a systematic review and meta-analysis of published literature to estimate the global prevalence of Mesocestoides spp. in major definitive and intermediate host taxa. Records published in English were collected from NCBI PubMed, Science Direct, Web of Science and Google Scholar databases, with 364 papers being included in the meta-analysis. The overall pooled prevalence estimates show that 21.72 % (95 % CI: 18.49-25.14) of terrestrial carnivore definitive hosts and 7.09 % (95 % CI: 5.79-8.51) of intermediate hosts are infected. Among definitive hosts, opossums and foxes were most commonly infected with pooled global prevalence of 48.16 % (95 % CI: 14.62 - 82.69) and 35.97 % (295 % CI: 9.54 - 42.66) respectively. Pooled global prevalence in domestic dogs and cats were 7.97 % (95 % CI: 5.67 - 10.63) and 8.32 % (95 % CI: 3.78 - 14.41) respectively. Among intermediate hosts, birds and snakes were most commonly infected with pooled global prevalence of 16.19 % (95 %CI: 5.9 - 30.31) and 15.74 % (95 % CI: 10.59 - 21.69) respectively. Our analysis demonstrates that prevalence of Mesocestoides spp. is variable across the world. The sylvatic cycle in wild hosts is likely to be more important than the domestic cycle for the maintenance of Mesocestoides spp. globally. Currently available genetic data at the mitochondrial COI locus was also phylogenetically analyzed. The genetic data supports the taxonomic distinctiveness of only a few of the numerous morphologically described Mesocestoides spp.

First description of peritoneal and pleural metacestodosis caused by Mesocestoides vogae in a European wild cat (Felis silvestris silvestris)

Tapeworms of the genus Mesocestoides (Cestoda: Cyclophyllidea: Mesocestoididae) are still enigmatic to scientists, due to their high morphological variability, low host specificity, and unknown details of their life cycle. They are found worldwide, with carnivorous mammals as the main definitive hosts, and the disease is potentially zoonotic. After ingestion by a definitive host, the tetrathyridium can occasionally migrate through the intestinal wall and reach the peritoneal cavity or abdominal organs causing peritoneal metacestodosis. Here, we report on a case of metacestodosis of a European wild cat (Felis silvestris silvestris) found dead in Croatia. At necropsy, a large number of white, rice-like structures were found free in the abdominal and thoracic cavities, as well as along the serous surfaces and in the lungs. DNA isolated from the nodules was genotyped and based on a 320-base pair long 12S fragment classified as Mesocestoides vogae. Although post-mortem changes were advanced, severe emaciation due to the severe parasitic infection and gastrointestinal bleeding was diagnosed as the likely cause of death. Intestinal cestodosis was previously reported in wild cats, but according to our knowledge, this is the first description of peritoneal and pleural metacestodosis caused by M. vogae tetrathyridia (metacestodes) in any wild carnivore species.

Endoparasitic fauna of two South American foxes in Chile: Lycalopex culpaeus and Lycalopex griseus

Native foxes face serious threats related to anthropic activities and the uncontrolled pets. However, the transmission of several pathogens such as parasites by domestic dogs is an important conservation issue with limited attention in Chile. The lack of a proper identification of the helminths of wild canids in the country, based mostly in coprological studies, limited our knowledge in potential interspecific transmission. Thus, the aim of the present survey was to identify the parasitic fauna of two native canids, the Andean fox (Lycalopex culpaeus) (n=49) and Chilla (Lycalopex griseus) (n=17), from several localities in Chile through a complete parasitological survey. Sixteen different species were identified, 9 of which are new host records for Andean fox and two for Chilla fox in South America, and three are recorded for first time in Chile. Also, five of them are of zoonotic concern and six are known to use domestic dogs as their principal hosts. These findings have implications for public health and the conservation of canids whose interspecific transmission of parasites with domestic dogs is confirmed through these findings. The need for an exhaustive surveillance of wild carnivores is emphasized considering these hosts as important sources of micro- and macroparasites.

Rodents as intermediate hosts of cestode parasites of mammalian carnivores and birds of prey in Poland, with the first data on the life-cycle of Mesocestoides melesi

Background

Rodents constitute an important part of the diet of many carnivore species. This predator-prey food chain is exploited by helminth parasites, such as cestodes, whose larval stages develop in rodents and then mature to the adult stage in predators. The main aim of our study was to use molecular techniques for identification of cestode species recovered from both intermediate and definitive hosts, with a particular focus on the genus Mesocestoides.

Methods

Larval cestodes were obtained during our long-term studies on rodent helminth communities in the Mazury Lake District in the north-east Poland in 2000–2018. Cestode larvae/cysts were collected from body cavities or internal organs (e.g. liver) during autopsies. Adult tapeworms were derived from nine red foxes, three Eurasian badgers and one Eurasian lynx. PCR amplification, sequencing and phylogenetic analyses were conducted employing three genetic markers: 18S rDNA, mitochondrial (mt) 12S rDNA and the mt cytochrome c oxydase subunit 1 (cox1) gene fragment.

Results

Altogether 19 Mesocestoides samples were analyzed, including 13 adult tapeworms from definitive hosts and six larval samples from 4 bank voles and 2 yellow-necked mice. Phylogenetic analyses revealed three well-supported trees of similar topology. In each case the Mesocestoides samples formed two separate clades. All isolates from foxes, the lynx isolate and two isolates from rodents grouped with Mesocestoides litteratus. Four isolates from rodents and all three isolates from Eurasian badgers were resolved in a separate clade, most similar to North American M. vogae (syn. M. corti). Examination of fixed, stained adult specimens from Eurasian badgers revealed consistency with the morphology of Mesocestoides melesi. Therefore, this clade is likely to represent M. melesi, a species first described in 1985 from the Eurasian badger Meles meles. Molecular analysis allowed also the identification of Taenia crassiceps, Hydatigera kamiyai and Cladotaenia globifera among larvae derived from rodents.

Conclusions

Molecular and phylogenetic analyses support the recognition of M. melesi as a valid species. Our data represent the first record of the larvae of this species in rodents. This is the first report on the occurrence of H. kamiyai in rodents from Poland.

First molecular identification of the tapeworm Mesocestoides litteratus from an Italian wall lizard (Podarcis siculus)

The cyclophyllidean cestodes of the genus Mesocestoides are parasites infecting a variety of carnivorous vertebrates. The complete life cycle of these tapeworms is not clear yet, but some reptiles, amphibians, birds and micro-mammals have been indicated as intermediate hosts. Although Mesocestoides spp. are considered endemic in Europe, infections by the metacestode form, the tetrathyridium, are reported less commonly than are infections by adult worms. In the present study, a peritoneal infection by Mesocestoides tetrathyridia in a wall lizard (Podarcis siculus) collected in central Italy is described. The phylogenetic position of the metacestodes was assessed using the barcode region COI and species delimitation methods, i.e. Automatic Barcode Gap Discovery (ABGD) and Bayesian implementation of the Poisson Tree Processes model (bPTP). COI sequence analysis assigned the isolates from the wall lizard to Mesocestoides litteratus, as confirmed by species delimitation and phylogenetic analyses. M. litteratus has been observed in Europe mainly in the definitive hosts (dogs, cats and foxes), and never identified in the Mediterranean region. This study represents the first evidence of parasitic infection by tetrathyridia of M. litteratus in P. siculus in Italy.

The forgotten exotic tapeworms: a review of uncommon zoonotic Cyclophyllidea

As training in helminthology has declined in the medical microbiology curriculum, many rare species of zoonotic cestodes have fallen into obscurity. Even among specialist practitioners, knowledge of human intestinal cestode infections is often limited to three genera, Taenia, Hymenolepis and Dibothriocephalus. However, five genera of uncommonly encountered zoonotic Cyclophyllidea (Bertiella, Dipylidium, Raillietina, Inermicapsifer and Mesocestoides) may also cause patent intestinal infections in humans worldwide. Due to the limited availability of summarized and taxonomically accurate data, such cases may present a diagnostic dilemma to clinicians and laboratories alike. In this review, historical literature on these cestodes is synthesized and knowledge gaps are highlighted. Clinically relevant taxonomy, nomenclature, life cycles, morphology of human-infecting species are discussed and clarified, along with the clinical presentation, diagnostic features and molecular advances, where available. Due to the limited awareness of these agents and identifying features, it is difficult to assess the true incidence of these ‘forgotten’ cestodiases as clinical misidentifications are likely to occur. Also, the taxonomic status of many of the human-infecting species of these tapeworms is unclear, hampering accurate species identification. Further studies combining molecular data and morphological observations are necessary to resolve these long-standing taxonomic issues and to elucidate other unknown aspects of transmission and ecology.

Significance of the red fox as a natural reservoir of intestinal zoonoses in Vojvodina, Serbia

In the present study, 223 foxes were collected from various localities in the northern part of the Republic of Serbia (Vojvodina province) and examined for intestinal helminths. Among the examined foxes 178 (79.8%) were infected. The most frequently identified parasites were Mesocestoides spp. (49.3%) and Toxascaris leonina (36.3%). The parasite with the lowest prevalence was Pterygodermatites affinis (0.9%), and this is the first confirmed finding in Serbia. The other recovered species were Alaria alata (25.6%), Taenia spp. (6.3%), Echinococcus multilocularis (13%), Toxocara canis (16.6%) and Uncinaria stenocephala (14.8%). The highest number of foxes infected with E. multilocularis were in the Srem area. The results of this study indicate the presence of helminth species in red foxes in Vojvodina which may also infect humans.

Gastrointestinal helminths of wolves (Canis lupus Linnaeus, 1758) in Piedmont, north-western Italy

Free-ranging grey wolves (Canis lupus), which are presently recolonizing Italy, can be parasitized by a diversity of helminths, but have rarely been subject to studies of their parasites. Therefore, this study aims to determine the prevalence of gastrointestinal helminths of road-killed grey wolves from the Piedmont region of Italy. Forty-two wolves were collected and examined for the presence of helminths. We recorded 12 helminth species: nine Nematoda and three Cestoda. The nematodes were: Ancylostoma caninum (7.1%), Capillaria sp. (2.4%), Molineus sp. (2.4%), Pterygodermatites affinis (11.9%), Physaloptera sibirica (9.5%), Toxocara canis (9.5%), Toxascaris leonina (2.4%) and Uncinaria stenocephala (26.2%); the cestodes were: Dipylidium caninum (4.8%), Mesocestoides sp. (4.8%) and Taenia multiceps (76.2%). Physaloptera sibirica had the highest mean intensity and T. multiceps had the highest prevalence. Based on age and sex, no differences in the intensity or prevalence of helminth species were found among the hosts. Molineus sp. was recorded for the first time in wolves from the Palearctic region; P. affinis and P. sibirica are respectively reported for the first time in wolves from Europe and Italy.

Massive infection of a song thrush by Mesocestoides sp. (Cestoda) tetrathyridia that genetically match acephalic metacestodes causing lethal peritoneal larval cestodiasis in domesticated mammals

Background

Peritoneal larval cestodiasis induced by Mesocestoides Vaillant, 1863 (Cyclophyllidea: Mesocestoididae) is a common cause of severe infections in domestic dogs and cats, reported also from other mammals and less frequently from birds. However, there is a limited knowledge on the taxonomy of causative agents of this disease.

Results

In the present study, we investigated a massive, likely lethal, infection of a song thrush Turdus philomelos (Passeriformes: Turdidae) by Mesocestoides sp. tetrathyridia. We performed combined morphological and phylogenetic analysis of the tetrathyridia and compared them with the materials obtained previously from other birds and mammals. The metrical data fitted within the wide range reported by previous authors but confirmed the limited value of morphological data for species identification of tetrathyridia of Mesocestoides spp. The molecular analyses suggested that the isolates represented an unidentified Mesocestoides sp. that was previously repeatedly isolated and sequenced in larval and adult forms from domestic dogs and cats in Europe, the Middle East and North Africa. In contrast to the present study, which found encysted tetrathyridia, four of the five previous studies that identified the same species described infections by acephalic metacestodes only.

Conclusions

The tetrathyridia of the examined Mesocestoides sp. are described in the present study for the first time. However, the possible match with the species that were previously reported to infect birds remains uncertain. The phylogenetic analyses also suggested the rejection of two cases that were previously identified as Mesocestoides corti as they were likely caused by the same species as in the presently reported infection case. The newly provided DNA sequences should allow the assignment to species in the future, when adults of the genus Mesocestoides are more thoroughly sequenced.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3480-1) contains supplementary material, which is available to authorized users.

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.

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The present study reports a the olive baboon as new host for the larval form of Taenia serialis.

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This is the first report of T. serialis in Benin.

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The relevance and risk for the health and welfare of primates in rescues centers is discussed.

Molecular identification of Mesocestoides sp. metacestodes in a captive gold-handed tamarin (Saguinus midas)

Mesocestoides spp. are tapeworms harbored in the intestine of many domestic and wild carnivores, birds of prey and, rarely, of humans. The life cycle is assumed to involve three hosts and the metacestode juvenile stage (tetrathyridium) may reproduce asexually, provoking severe systemic infections. In the present study, a case of a peritoneal infection by Mesocestoides sp. occurred in a captive gold-handed tamarin (Saguinus midas) is described. Phylogenetic positions based on CO1 and 12S loci were analysed to describe in details this unusual finding of Mesocestoides in a callitrichid monkey. The phylogenetic analyses has not clearly resolve relationships between the metacestode forms from the tamarin and any of the described Mesocestoides species available so far, including those described from non-human primates, thus supporting the hypothesis of a new taxon within the genus.

Mesocestoides sp. in Wild Northern Bobwhite ( Colinus virginianus) and Scaled Quail ( Callipepla squamata)

Mesocestoides spp. have a cosmopolitan distribution with zoonotic potential. Mesocestoides tetrathyridia were found under the pericardial sac, on the surface of the crop, and in the peritoneal cavity of a hunter-harvested Northern Bobwhite ( Colinus virginianus) and a Scaled Quail ( Callipepla squamata) collected during the 2016-17 quail hunting season in northwest and southern Texas, US respectively. Molecular analysis indicated that the tetrathyridia from the birds likely belonged to an undescribed species and are identical to pretetrathyridium stages recently found in Scincella lateralis skinks in Oklahoma. This is the first report of Mesocestoides from North American birds.

Morphological and Molecular Characterization of Post-Larval Pre-Tetrathyridia of Mesocestoides sp. (Cestoda: Cyclophyllidea) from Ground Skink, Scincella lateralis (SAURIA: SCINCIDAE), FROM SOUTHEASTERN OKLAHOMA

Free pre-tetrathyridia of Mesocestoides sp. are described, for the first time, from samples obtained from the coelomic cavity of a ground skink, Scincella lateralis, from Oklahoma. Closer examination of these early-stage tapeworms revealed they were transitional metamorphosis stages between a post-hexacanth procercoid form to the full metacestode of Mesocestoides. A series of transitional stages was found that span the full period of sucker and apical organ development. However, we did not see any fully developed tetrathyridia, i.e., having classic Mesocestoides morphology but with the apical sucker absent following developmental atrophy. This is the first time that metamorphic pre-tetrathyridial stages of a Mesocestoides sp. have been reported in vivo from a natural infection. These observations corroborate earlier reports of such stages of Mesocestoides vogae developed in vitro, though the previously reported isolate of M. vogae is asexually proliferative, and the species from the present study showed no sign of asexual proliferation. The fact that these immediately post-hexacanth stages can occur in a single lizard intermediate host may suggest that Mesocestoides spp. might develop through a simple 2-host life cycle rather than an obligate 3-host cycle that has been speculated to occur by most previous authors. DNA sequence comparisons and phylogenetic analyses based on mitochondrial 12S, cox1, and nad1 genes have demonstrated that our specimens from S. lateralis represent a species clearly distinct from all previously sequenced Mesocestoides and closely related to 2 forms from domestic dogs and Channel Island fox in California previously published as Mesocestoides sp. C.

Identifying wildlife reservoirs of neglected taeniid tapeworms: Non-invasive diagnosis of endemic Taenia serialis infection in a wild primate population

Despite the global distribution and public health consequences of Taenia tapeworms, the life cycles of taeniids infecting wildlife hosts remain largely undescribed. The larval stage of Taenia serialis commonly parasitizes rodents and lagomorphs, but has been reported in a wide range of hosts that includes geladas (Theropithecus gelada), primates endemic to Ethiopia. Geladas exhibit protuberant larval cysts indicative of advanced T. serialis infection that are associated with high mortality. However, non-protuberant larvae can develop in deep tissue or the abdominal cavity, leading to underestimates of prevalence based solely on observable cysts. We adapted a non-invasive monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA) to detect circulating Taenia spp. antigen in dried gelada urine. Analysis revealed that this assay was highly accurate in detecting Taenia antigen, with 98.4% specificity, 98.5% sensitivity, and an area under the curve of 0.99. We used this assay to investigate the prevalence of T. serialis infection in a wild gelada population, finding that infection is substantially more widespread than the occurrence of visible T. serialis cysts (16.4% tested positive at least once, while only 6% of the same population exhibited cysts). We examined whether age or sex predicted T. serialis infection as indicated by external cysts and antigen presence. Contrary to the female-bias observed in many Taenia-host systems, we found no significant sex bias in either cyst presence or antigen presence. Age, on the other hand, predicted cyst presence (older individuals were more likely to show cysts) but not antigen presence. We interpret this finding to indicate that T. serialis may infect individuals early in life but only result in visible disease later in life. This is the first application of an antigen ELISA to the study of larval Taenia infection in wildlife, opening the doors to the identification and description of infection dynamics in reservoir populations.

Although tapeworm parasites of the genus Taenia are globally distributed and inflict enormous socioeconomic and health costs on their hosts, which include humans, little is known about taeniid tapeworms that infect wildlife. This gap in knowledge prevents an assessment of the potential for these parasites to infect humans and production animals and is largely due to the difficulty of conducting standard diagnostic tests on wildlife. To address this gap, we adapted a standard diagnostic assay to be used with dried urine samples. We used urine from geladas, primates endemic to Ethiopia, which are frequently infected with the larval stage of a taeniid tapeworm and exhibit protuberant cysts during advanced infection. The use of this diagnostic test in a wild gelada population allowed us to detect that individuals can be infected without exhibiting observable cysts, and that some individuals may control infection in its early stages. This tool provides information about how a neglected tapeworm functions in a wildlife system and opens the door to the non-invasive identification of tapeworm reservoir hosts that may threaten humans.

Occurrence of Mesocestoides canislagopodis (Rudolphi, 1810) (Krabbe, 1865) in mammals and birds in Iceland and its molecular discrimination within the Mesocestoides species complex

The life cycle of Mesocestoides tapeworms (Cestoda: Cyclophyllidea: Mesocestoididae) requires three hosts. The first intermediate host is unknown but believed to be an arthropod. The second intermediate host is a vertebrate. The primary definitive host is a carnivore mammal, or a bird of prey, that eats the tetrathyridium-infected second intermediate host. One representative of the genus, Mesocestoides canislagopodis, has been reported from Iceland. It is common in the arctic fox (Vulpes lagopus) and has also been detected in domestic dogs (Canis familiaris) and cats (Felis domestica). Recently, scolices of a non-maturing Mesocestoides sp. have also been detected in gyrfalcon (Falco rusticolus) intestines, and tetrathyridia in the body cavity of rock ptarmigan (Lagopus muta). We examined the taxonomic relationship of Mesocestoides from arctic fox, gyrfalcon, and rock ptarmigan using molecular methods, both at the generic level (D1 domain LSU ribosomal DNA) and at the specific level (cytochrome c oxidase subunit I (COI) and 12S mitochondrial DNA). All stages belonged to Mesocestoides canislagopodis. Phylogenetic analysis of the combined 12S-COI at the specific level confirmed that M. canislagopodis forms a distinct clade, well separated from three other recognized representatives of the genus, M. litteratus, M. lineatus, and M. corti/vogae. This is the first molecular description of this species. The rock ptarmigan is a new second intermediate host record, and the gyrfalcon a new primary definitive host record. However, the adult stage seemed not to be able to mature in the gyrfalcon, and successful development is probably restricted to mammalian hosts.

Fitness impacts of tapeworm parasitism on wild gelada monkeys at Guassa, Ethiopia

Parasitism is expected to impact host morbidity or mortality, although the fitness costs of parasitism have rarely been quantified for wildlife hosts. Tapeworms in the genus Taenia exploit a variety of vertebrates, including livestock, humans, and geladas (Theropithecus gelada), monkeys endemic to the alpine grasslands of Ethiopia. Despite Taenia's adverse societal and economic impacts, we know little about the prevalence of disease associated with Taenia infection in wildlife or the impacts of this disease on host health, mortality and reproduction. We monitored geladas at Guassa, Ethiopia over a continuous 6½ year period for external evidence (cysts or coenuri) of Taenia-associated disease (coenurosis) and evaluated the impact of coenurosis on host survival and reproduction. We also identified (through genetic and histological analyses) the tapeworms causing coenurosis in wild geladas at Guassa as Taenia serialis. Nearly 1/3 of adult geladas at Guassa possessed ≥1 coenurus at some point in the study. Coenurosis adversely impacted gelada survival and reproduction at Guassa and this impact spanned two generations: adults with coenuri suffered higher mortality than members of their sex without coenuri and offspring of females with coenuri also suffered higher mortality. Coenurosis also negatively affected adult reproduction, lengthening interbirth intervals and reducing the likelihood that males successfully assumed reproductive control over units of females. Our study provides the first empirical evidence that coenurosis increases mortality and reduces fertility in wild nonhuman primate hosts. Our research highlights the value of longitudinal monitoring of individually recognized animals in natural populations for advancing knowledge of parasite-host evolutionary dynamics and offering clues to the etiology and control of infectious disease.

Mutation scanning analysis of genetic variation within and among Echinococcus species: implications and future prospects

Adult tapeworms of the genus Echinococcus (family Taeniidae) occur in the small intestines of carnivorous definitive hosts and are transmitted to particular intermediate mammalian hosts, in which they develop as fluid-filled larvae (cysts) in internal organs (usually lung and liver), causing the disease echinococcosis. Echinococcus species are of major medical importance and also cause losses to the meat and livestock industries, mainly due to the condemnation of infected offal. Decisions regarding the treatment and control of echinococcosis rely on the accurate identification of species and population variants (strains). Conventional, phenetic methods for specific identification have some significant limitations. Despite advances in the development of molecular tools, there has been limited application of mutation scanning methods to species of Echinococcus. Here, we briefly review key genetic markers used for the identification of Echinococcus species and techniques for the analysis of genetic variation within and among populations, and the diagnosis of echinococcosis. We also discuss the benefits of utilizing mutation scanning approaches to elucidate the population genetics and epidemiology of Echinococcus species. These benefits are likely to become more evident following the complete characterization of the genomes of E. granulosus and E. multilocularis.

Characterization of Haemaphysalis flava (Acari: Ixodidae) from Qingling subspecies of giant panda (Ailuropoda melanoleuca qinlingensis) in Qinling Mountains (Central China) by morphology and molecular markers

Tick is one of important ectoparasites capable of causing direct damage to their hosts and also acts as vectors of relevant infectious agents. In the present study, the taxa of 10 ticks, collected from Qinling giant pandas (Ailuropoda melanoleuca qinlingensis) in Qinling Mountains of China in April 2010, were determined using morphology and molecular markers (nucleotide ITS2 rDNA and mitochondrial 16S). Microscopic observation demonstrated that the morphological features of these ticks were similar to Haemaphysalis flava. Compared with other Haemaphysalis species, genetic variations between Haemaphysalis collected from A. m. qinlingensis and H. flava were the lowest in ITS2 rDNA and mitochondrial 16S, with sequence differences of 2.06%–2.40% and 1.30%–4.70%, respectively. Phylogenetic relationships showed that all the Haemaphysalis collected from A. m. qinlingensis were grouped with H. flava, further confirmed that the Haemaphysalis sp. is H. flava. This is the first report of ticks in giant panda by combining with morphology and molecular markers. This study also provided evidence that combining morphology and molecular tools provide a valuable and efficient tool for tick identification.

Cestode infection in 2 dogs: cytologic findings in liver and a mesenteric lymph node

Mesocestoides cestode infections in dogs are well known for causing severe peritonitis with larvae or larval fragments (metacestodes, tetrathyridia, or calcareous corpuscles) frequently observed cytologically in peritoneal fluid samples. This case report describes the cytologic and clinical features of 2 dogs infected with cestode larvae, with one case confirmed and the other presumed to be Mesocestoides sp. In these 2 unusual cases, cestode larvae or larval fragments were found in fine-needle aspirates of the liver and a mesenteric lymph node, but no organisms were found in peritoneal fluid samples. The data presented in this report indicate that clinical pathologists should not rule out Mesocestoides sp cestodiasis based on the absence of larvae in peritoneal fluid samples from dogs.

Use of a molecular approach for the definitive diagnosis of proliferative larval mesocestoidiasis in a cat

A 9 year-old male, neutered cat with a history of a sudden onset of lethargy, anorexia and respiratory distress was presented in a veterinary practice in Lucca, Italy. A clinical examination revealed that the cat was severely dehydrated, and had pale mucous membranes and tachypnoea. No pain or discomfort was detected at the time of physical examination. The cat was administered fluids, antibiotics and supportive therapy, but died overnight. The owner of the cat requested for a post mortem examination to be conducted. At necropsy, acephalic structures, consistent with proliferative tapeworm (cestode) larvae, were detected in the thoracic cavity on pleural surfaces. As these larvae could not be identified to genus or species by microscopy, a PCR-based sequencing-phylogenetic approach was used. Part of the cytochrome c oxidase subunit 1 gene was PCR-amplified from genomic DNAs from five individual larvae and sequenced; all five sequences obtained were identical. This consensus sequence was aligned (over 355 nucleotide positions) with homologous sequences representing a range of cestodes (including Echinococcus granulosus, Echinococcus multilocularis, Hymenolepis microstoma, Mesocestoides spp. and Taenia saginata) from previously published studies and then subjected to phylogenetic analysis. The sequence representing the larval cestode from the affected cat grouped, with strong statistical support, with those representing Mesocestoides corti and Mesocestoides lineatus. Therefore, a definitive diagnosis of pleural proliferative larval mesocestoidiasis could be made. This study illustrates the value of using molecular tools to directly assist clinical and pathological investigations of cestodiases of animals.

Molecular identification of Mesocestoides spp. from intermediate hosts (rodents) in central Europe (Poland)

Genus Mesocestoides is a representative of the small cyclophyllidean family Mesocestoididae that is found parasitizing the small intestine of carnivores. The life cycle of cestodes from this genus is complex and requires two intermediate hosts. Cysticercoids are produced in the first intermediate host (oribatid mites), which when eaten by the second intermediate host (mainly rodents, but also other mammalian species, birds, reptiles, or amphibians) form tetrathyridia in the body cavity. Because of the rich history of nomenclatural evaluation of Mesocestoididae, the taxonomic status within the genus Mesocestoides is still unclear. Additional problem constitute the difficulty or even the impossibility in the determination of tetrathyridia based on morphological features. Thus, the aim of our study was to identify a molecular characteristic of the isolates of Mesocestoides from the second intermediate hosts (rodents) based on nuclear and mitochondrial ribosomal DNA data. We choose to analyze metacestodes isolated from two species of rodents (Apodemus agrarius and Myodes glarolus) from different sites. As a result of amplification of 18S rDNA, we obtained partial sequences from four isolates ranging from 1,116 to 1,162 bp. In relation to mitochondrial sequence, 354 bp product of 12S rDNA was obtained from one isolate. The neighbor joining and maximum parsimony trees were constructed in order to examine the phylogenetic relationship within Mesocestoides spp. occurring in rodents from central Europe. The results of our research on the larval stages from rodents, living in a periphery of urban agglomeration as well as in an area of reserve protection, confirm the data of more frequently occurring Mesocestoides litteratus.

Molecular and morphological circumscription ofMesocestoidestapeworms from red foxes (Vulpes vulpes) in central Europe

Here we examine 3157 foxes from 6 districts of the Slovak Republic in order to determine for the first time the distribution, prevalence and identity ofMesocestodesspp. endemic to this part of central Europe. During the period 2001–2006, an average of 41·9% of foxes were found to harbourMesocestoidesinfections. Among the samples we confirmed the widespread and common occurrence ofM. litteratus(Batsch, 1786), and report the presence, for the first time, ofM. lineatus(Goeze, 1782) in the Slovak Republic, where it has a more restricted geographical range and low prevalence (7%). Using a combination of 12S rDNA, CO1 and ND1 mitochondrial gene sequences together with analysis of 13 morphometric characters, we show that the two species are genetically distinct and can be differentiated by discrete breaks in the ranges of the male and female reproductive characters, but not by the more commonly examined characters of the scolex and strobila. Estimates of interspecific divergence withinMesocestoidesranged from 9 to 18%, whereas intraspecific variation was less than 2%, and phylogenetic analyses of the data showed that despite overlapping geographical ranges, the two commonly reported European species are not closely related, withM. litteratusmore closely allied to North American isolates ofMesocestoidesthan toM. lineatus. We confirm that morphological analysis of reproductive organs can be used to reliably discriminate between these often sympatric species obtained from red foxes.

First larval record of Mesocestoides in carnivora of Tenerife (Canary Islands)

Larvae of Mesocestoides sp. were recovered in Tenerife (Canary Islands) in 2004 from the peritoneal cavities of 2 domestic dogs and a domestic cat. Morphological and molecular identification were carried out. Mesocestoides litteratus from Vulpes vulpes was sequenced for the first time using the ITS-2 region (18S rDNA), and was included in the phylogenetic analysis to compare the sequence variability among these and other Mesocestoides spp. belonging to different carnivores. Phylogenetic studies were carried out based on maximum parsimony and neighbor-joining analysis. The results showed the relationships between these and other previously published Mesocestoides species. Moreover, it is demonstrated that Mesocestoides sp. from Tenerife comprises a previously unreported sequence. This is the first larval record of Mesocestoides sp. in domestic animals from Tenerife, Canary Islands, Spain.

Genetic characterization of members of the genus Contracaecum (Nematoda: Anisakidae) from fish-eating birds from west-central Florida, USA, with evidence of new species

Specimens of Contracaecum spp. from Phalacrocorax auritus and Pelecanus occidentalis from Florida were characterized by sequencing of the small subunit of the mitochondrial ribosomal RNA gene (rrnS) and by PCR-based RFLP analysis of the same gene and of the internal transcribed spacers (ITS) of nuclear ribosomal DNA. Analyses of the rrnS sequence data using the MP and UPGMA approaches yielded trees with similar topologies, delineating 3 main clusters. Specimens from Ph. auritus, morphologically assigned to C. rudolphii (s.l.), were part of the cluster comprising also the other 2 species of the C. rudolphii complex (A and B), but representing a genetically distinct group, potentially corresponding to a distinct lineage within the complex, provisionally named as C. rudolphii C. The second cluster comprised 5 individuals from P. occidentalis, which formed a genetically relatively homogeneous group. The rrnS data indicate that these specimens (indicated as Contracaecum sp. 1) are clearly genetically different from the morphologically most closely related species, i.e. C. rudolphii (s.l.) and C. microcephalum, and could represent a new species. The third cluster comprised 7 specimens from P. occidentalis morphologically assigned to C. multipapillatum (s.l.). These were shown to be genetically homogeneous and related to but quite distinct from C. multipapillatum from Greece, although additional studies are needed to assess their status. PCR-RFLP based markers for the quick identification of these taxa are provided.