Tapeworms of the Chaco Boreal, Paraguay, with two new species

Prevalence study of Echinococcus granulosus in guanaco (Lama guanicoe) from the Chilean Patagonia unexpectedly reveals the southernmost limit of Taenia omissa

This study presents the first detection of Taenia omissa metacestodes in guanaco (Lama guanicoe) within the Chilean Patagonia, marking the southernmost record of natural infection in an intermediate host on the continent. Taenia omissa was found in the continental part of the Magallanes region where the top predators are pumas (Puma concolor). Conversely, all metacestodes found in guanacos collected from Tierra del Fuego Island, where no pumas exist, were identified solely as Echinococcus granulosus sensu stricto. Additionally, this research highlights a tissue preference of T. omissa for liver, contrasting with E. granulosus, which predominantly affects the lungs in guanacos. We also report the infection of T. pisiformis in 1 guanaco. Our findings emphasize the need for accurate identification of metacestodes during meat inspection in an area where T. omissa and E. granulosus overlap. This research also contributes to increase the knowledge of parasite–host dynamics in wildlife and underscores the importance of considering broader spectrum intermediate hosts in the epidemiology of parasitic infections.

Diversity and biology of Spirometra tapeworms (Cestoda: Diphyllobothriidea), zoonotic parasites of wildlife: A review

Tapeworms of the genus Spirometra Faust, Campbell et Kellogg, 1929 have long been known as intestinal parasites of carnivores and their larvae (spargana) have been found in various vertebrates. Nevertheless, their species diversity, host associations and geographical distribution remain poorly understood. Molecular data clearly confirm the validity of the genus, which has been synonymised by several authors with Diphyllobothrium Cobbold, 1858. Despite morphological similarities between the species of the two genera, they are not closely related and also differ in their life cycle. The present review provides a list of the species recognised as valid and additional genotypes that may represent other species, with a basic characterisation of each taxon and comments on their validity, the probable range of definitive and intermediate hosts, and their distribution. The existing taxonomic problems and the insufficient knowledge of the host specificity and distribution of Spirometra tapeworms can only be solved by combining molecular and morphological data, i.e. by comparing genetically characterised specimens with corresponding morphological vouchers (hologenophores). Further targeted sampling and surveys are required to clarify the distribution and host associations.

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.

The red brocket deer (Mazama americana) as a new intermediate host of Taenia omissa (Taeniidae)

A total of 13 metacestodes were collected from the lung and parietal pleura from a red brocket deer (Mazama americana) from the Peruvian Amazon. All metacestodes were identified as cysticerci of Taenia omissa by morphological and molecular analyzes. Cytochrome c oxidase subunit 1 sequences from the new isolate T. omissa had more than 96.8% identity with other Peruvian isolates of the species previously sequenced. Lower similarities (93.8-95.8%) were verified between Peruvian and Canadian isolates. This finding adds a new intermediate host for T. omissa and also expands its geographical distribution.

Intestinal Parasites of Neotropical Wild Jaguars, Pumas, Ocelots, and Jaguarundis in Colombia: Old Friends Brought Back from Oblivion and New Insights

Neotropical wild felids (NWF) are obligate carnivore species present in Central and South America, and some are considered endangered due to constantly decreasing populations. NWF can become infected by a wide range of protozoan and metazoan parasites, some of them affecting their health conditions and others having anthropozoonotic relevance. Parasitological studies on NWF are still very scarce, and most data originated from dead or captive animals. On this account, the current study aimed to characterize gastrointestinal parasites of free-ranging jaguars (Panthera onca), pumas (Puma concolor), ocelots (Leopardus pardalis), and jaguarundis (Herpailurus yagouaroundi), i.e., four out of six NWF species endemic to Colombia. Fecal samples from jaguars (n = 10) and ocelots (n = 4) were collected between 2012 and 2017 as part of the Jaguar Corridor Initiative from six geographic locations in Colombia. In addition, cestode specimens were obtained during puma and jaguarundi necropsies. Scat samples were processed by standardized sodium acetate-acetic acid-formalin (SAF), sedimentation, and flotation techniques and by carbol fuchsin-stained fecal smears. Morphological evaluation of feces showed the presence of one cestode (Spirometra sp.), a nematode (Toxocara cati), an acanthocephalan (Oncicola sp.), and one cyst-forming coccidian (Cystoisospora-like oocysts). Feces oocysts were submitted to a Toxoplasma gondii-specific PCR for species identification, but no product was amplified. The cestodes isolated from a puma and jaguarundi were molecularly characterized by sequencing cytochrome c oxidase subunit I, identifying them as Taenia omissa and as a T. omissa sister lineage, respectively. These results collectively demonstrate the potential role of NWF as natural reservoir hosts for neglected zoonotic parasites (e.g., Spirometra sp., T. cati) and highlight their possible role in parasite transmission to human communities. Due to public health concerns, the occurrence of these parasites should be monitored in the future for appropriate zoonotic management practices in conservation strategies and wild felid health management programs.

Morphological and molecular identification of helminths of the greater bulldog bat Noctilio leporinus (Quiroptera: Noctilionidae) from Campeche, Mexico

Surveys on parasites of bats from the Americas have been conducted, but information on helminths is still scarce, especially in the Neotropical region. In Mexico, there are species of bats that lack of a record for helminth species, such as members of the family Noctilionidae. The present study describes for the first time the helminths of Noctilio leporinus in Campeche, Mexico. In 2017, six specimens of N. leporinus were studied for helminths. The species identification of helminths was based on morphological studies and molecular analysis of fragments of the 28S rDNA. All bat specimens were infected for at least one helminth species. Three helminth taxa were identified: the trematode Pygidiopsis macrostomum, and the nematodes Tricholeiperia cf. proencai, and Heligmonellidae gen. sp. The morphological identification of P. macrostomum was confirmed by sequence analysis of 28S rDNA gene. The phylogeny of P. macrostomum grouped our sequence with other sequences of the same species collected in Brazil. The phylogenetic tree of Heligmonellidae gen. sp. indicated that the helminth belongs to clade formed by the species Odilia bainae, Nippostrongylus magnus and Nippostrongylus brasiliensis of the family Heligmonellidae. The phylogenetic analysis of the 28S sequences of T. cf. proencai did not show any similarity or close affinity with nematodes from which that gene has been sequenced to date. The findings of the present study increase the number of helminth species parasitizing bats in Mexico.

Caracterização da fauna helmintológica de tamanduá-bandeira (Myrmecophaga tridactyla) e tamanduá-mirim (Tamandua tetradactyla) atropelados nas rodovias BR-050 e BR-455 (Minas Gerais, Brasil)

RESUMO O tamanduá-bandeira (Myrmecophaga tridactyla) e o tamanduá-mirim (Tamandua tetradactyla) são mamíferos xenartros amplamente distribuídos no território nacional. Apesar disso, suas populações estão em constante ameaça, principalmente o primeiro, categorizado como vulnerável de acordo com classificação da União Internacional para Conservação da Natureza. Diante disso e da escassez de estudos com endoparasitas nesses animais, objetivou-se descrever a helmintofauna dessas duas espécies de tamanduá, utilizando espécimes atropelados nas rodovias BR-050 e BR-455, região do Triângulo Mineiro, Minas Gerais, Brasil. Os animais foram submetidos à necropsia, tendo seus órgãos e conteúdo intestinal e estomacal examinados para recuperação de helmintos. Os parasitos coletados foram identificados com base em suas características morfológicas e morfométricas. As espécies/os gêneros caracterizados para M. tridactyla e T. tetradactyla, suas respectivas prevalências, bem como órgãos de origem, foram: Gaphidiops dissimilis (33,33% e 0%) no estômago; Gigantorhynchus echinodiscus (25% e 66,66%) no intestino delgado; Physaloptera magnipapilla (50% e 66,6%) no estômago; e Mathevotaenia spp. (25% e 66,66%) no intestino delgado. Physaloptera magnipapilla foi a espécie com os maiores índices de infecção, e novo registro de localização foi registrado para o nematódeo Graphidiops dissimilis. Detectou-se uma provável sobreposição da área de vida dos tamanduás estudados, bem como uma helmintofauna característica da região.

Updated checklist of helminths found in terrestrial mammals of Argentine Patagonia

The aim of the present study was to evaluate the state of knowledge about the helminthology of wild mammals in Argentine Patagonia and its link with the conservation of parasite species and biodiversity. To this end, the information included in the previously reported checklist of the helminths found in terrestrial wild mammals of Argentine Patagonia was completed and updated. The methodology used for the search was the same as that previously used, with slight modifications. Eighty-two species of mammals currently inhabit the region, and an additional six species are considered to have become extinct before the 20th century. The reports used to complete and update the information correspond to research done since 2015 to date. Considering the number of records analysed in the previously reported checklist and those of the current update, a total of 1918 helminthological reports for current Patagonian mammals and 2141 on mammal species that inhabited Patagonia before the 20th century were accounted for. It is important to point out that 41% of the 82 species of wild mammals currently inhabiting Patagonia have not been studied helminthologically; 38% of these without helminthological records are either threatened or do not have categorization, and 79% of mammals without helminthological studies have some degree of endemism. Therefore, in order to evaluate conservation priorities, the information about the parasitic richness in Patagonian wild mammals should be substantially increased, especially in those endangered or endemic.

First record of Lagochilascaris minor (Nematoda: Ascarididae) in Leopardus geoffroyi (Carnivora: Felidae) in Brazil

Lagochilascariasis is a parasitic disease caused by nematodes of the genus Lagochilascaris. These parasites occur in the neotropical region and their definitive hosts are wild animals, domestic dogs and felids and, accidentally, humans. Here, infection by Lagochilascaris minor is recorded for the first time in a wild felid, in Brazil.

The alpaca (Vicugna pacos) as a natural intermediate host of Taenia omissa (Cestoda: Taeniidae)

Three metacestodes were collected from the mesentery and the surface of the liver of three adult alpacas (Vicugna pacos) in a slaughterhouse located in Puno, Peru. Various features of the metacestodes were observed for morphological identification. A molecular diagnosis was performed by PCR-based sequencing of mitochondrial genes of cytochrome c oxidase subunit 1 (cox1) and the NADH dehydrogenase subunit 1 (nad1). All metacestodes were identified as Taenia omissa by morphology and molecular methods The isolates from alpacas showed significant sequence similarity with previously reported isolates of T. omissa (95.7-98.1% in cox1 and 94.6-95.1% in nad1). Our report is the first to detect T. omissa metacestodes in alpacas and to reveal that alpacas are natural intermediate hosts for this parasite.

Parasitism by larval tapeworms genus Spirometra in South American amphibians and reptiles: new records from Brazil and Uruguay, and a review of current knowledge in the region

Spargana are plerocercoid larvae of cestode tapeworms of the genus Spirometra, Family Diphyllobothriidae, parasitic to frogs, reptiles, birds and mammals. This parasitic disease in humans can be transmitted through the use and consumption of amphibians and reptiles. The available knowledge about Spirometra in South America is scarce, and there are only a few reports on the occurrence of sparganum in amphibians and reptiles, many of them published in old papers not easily available to researchers. In this work we present a review on this topic, provide new records in two species of amphibians and 7 species of reptiles from Brazil and Uruguay respectively. We also summarize current knowledge of Spirometra in the continent, along with an updated of host taxonomy. We could gather from the literature a total of 15 studies about amphibian and reptile hosts, published between 1850 and 2016, corresponding to 43 case reports, mostly from Brazil (29) and Uruguay (8), Argentina (3), Peru (2), and Venezuela (1); the majority of them related to reptiles (five lizards and 26 snake species), and 14 corresponded to amphibians (9 anurans). Plerocercoid larvae were located in different organs of the hosts, such as subcutaneous tissue, coelomic cavity, peritoneum, and musculature. The importance of amphibians and reptiles in the transmission of the disease to humans in South America is discussed. Relevant issues to be studied in the near future are the taxonomic characterization of Spirometra in the region and the biological risk of reptile meat for aboriginal and other rural communities.

Molecular and morphological evidence of Taenia omissa in pumas (Puma concolor) in the Peruvian Highlands

A total of 41 cestodes were collected during necropsy examination on 2 pumas (Puma concolor) that were found in 2 communities in Canchis province, Cuzco region, Peru, at 4500 meters above sea level (Peruvian Andes). The cestodes were evaluated morphologically and molecularly. A fragment of the mitochondrial cytochrome c oxidase subunit 1 gene (cox1) was used as a genetic marker. All the cestodes were identified as Taenia omissa. In the present report, we give a brief description by molecular and morphological diagnosis of the cestodes and compare nucleotide sequences with previous isolates from GenBank. Upon comparison, the sequences showed a difference in the cox1 gene of 5.1 to 5.3% with other teniids sequences. This finding constitutes the first report of T. omissa in Peru and expands the geographic distribution of this parasite.

New host and distribution expansion for Pterygodermatites (Multipectines) affinis

The present study reports the first case of infection by Pterygodermatites affinis in Lycalopex gymnocercus, and the first report of this nematode in Argentina. Examining 80 foxes from Buenos Aires province, specimens of this species were recovered from 21.25 % of the small intestines and eggs were found in 7.5 % of the fecal samples.

The Pampas fox (Lycalopex gymnocercus) as new definitive host for Spirometra erinacei (Cestoda: Diphyllobothriidae)

Spirometra erinacei, Faust, Campbell and Kellogg, 1929, is a pseudophyllidean cestode of the family Diphyllobothriidae. The genus Spirometra is cosmopolitan and these parasites infect carnivores, specially felids and canids. In Argentina, S. erinacei and S. mansonoides have been reported sporadically only in domestic definitive hosts. The Pampas fox, Lycalopex gymnocercus, is the most abundant native carnivore in southern South America, where it inhabits grasslands and open woodlands and areas highly modified by extensive ranching and agricultural activities. This report describes the first finding of S. erinacei infecting Pampas fox, and provides an estimate prevalence of this cestode in rural areas of southern Buenos Aires province, Argentina based on 78 complete Pampas fox intestine samples analysis. This study found a 15.4% of prevalence of S. erinacei in small intestine (adult stage) and a 21.8% in fecal samples (egg stage). In the present work, the first case of S. erinacei in a wild definitive host from Argentina was reported expanding the list of definitive hosts of S. erinacei in South America.

New record of anoplocephalid eggs (Cestoda: Anoplocephalidae) collected from rodent coprolites from archaeological and paleontological sites of Patagonia, Argentina

Results of paleoparasitological examination of rodent coprolites collected from archaeological and paleontological sites from Patagonia, Argentina, are present. Each coprolite was processed, rehydrated, homogenized, spontaneously sedimented and examined using light microscope. Coprolites and eggs were described, measured and photographed, and were compared with current faeces of Lagidium viscacia. Eggs with morphological features, attributed to an anoplocephalid cestode were found in samples collected from Cueva Huenul 1 (36°56'45″S, 69°47'32″W, Neuquén Province, Holocene) and Los Altares Profile (43º53'35″S, 68º23'21″W, Chubut Province, Late Holocene). These are the first findings of this anoplocephalid from faecal material from patagonic rodents.

New species in the genus Monoecocestus (Cestoda: Anoplocephalidae) from neotropical rodents (Caviidae and Sigmodontinae)

Anoplocephalid cestodes have a worldwide distribution, but relatively few species are known from South American rodents. By examining the collections of the Harold W. Manter Laboratory of Parasitology and the United States National Parasite Collection, 6 new species of Monoecocestus Beddard, 1914, are described, along with a redescription of Monoecocestus mackiewiczi Schmidt and Martin, 1978, based on the type specimens. The discussion includes commentary about uterine development, an important taxonomic character of the family, the vaginal dilation in immature segments (a character of potential taxonomic importance), and the implication of host usage to the evolutionary history and biogeography of species in this genus.

Pappen F, Sinkoc AL, Brum JGW. Helmintos do cachorro do campo, Pseudalopex gymnocercus (Fischer, 1814) e do cachorro do mato, Cerdocyon thous (Linnaeus, 1766) no sul do estado do Rio Grande do Sul, Brasil

Quarenta canídeos selvagens foram capturados por "live trap" nos municípios de Pedro Osório e Pelotas, sul do estado do Rio Grande do Sul e transportados para o Laboratório de Parasitologia da Universidade Federal de Pelotas. Após serem necropsiados, segmentos do intestino, respiratório, urinário e fígado foram separados e examinados. Os crânios dos animais foram usados para identificação taxonômica. Dos 40 animais capturados, 22 (55%) foram Pseudalopex gymnocercus e 18 (45%) Cerdocyon thous. Os nematóides mais prevalentes foram: Ancylostoma caninum (45,4 em P. gymnocercus e 22,2% em C. thous), Molineus felineus (9,9 em P. gymnocercus e 5,6% em C. thous), Strongyloides sp. (22,7 em P. gymnocercus e 16,7% em C. thous), Trichuris sp. (13,6 em P. gymnocercus e 11,1% em C. thous), e Capillaria hepatica (13,6 em P. gymnocercus e 5,5 % em C. thous). Os trematódeos observados foram: Alaria alata (50,0% em C. thous e 36,4 em P. gymnocercus), e Asthemia heterolecithodes em 5,6% dos C. thous. Cestóides foram identificados como Spirometra sp. (61,1% em C. thous e 54,5 em P. gymnocercus), Diphyllobothriidae (81,8 em P. gymnocercus e 77,8% em C. thous), e Acantocephala do gênero Centrorhynchus foi observado somente em 5,6% dos C. thous. Estes resultados indicaram a helmintofauna de canídeos selvagens nas áreas estudadas.

Helminths of rabbits (Lagomorpha, Leporidae) deposited in the Helminthological Collection of the Oswaldo Cruz Institute

Helminth samples (n = 35) recovered from Oryctolagus cuniculus (Linnaeus, 1758) Lilljeborg, 1873 (3) and from another rabbit species, Sylvilagus brasiliensis (Linnaeus, 1758) Thomas, 1901 (32), from August 1909 to February 1948 and that are deposited in the Helminthological Collection of the Oswaldo Cruz Institute were analyzed. The studied samples were represented by the cysticercus of the cestode Taenia pisiformis (Bloch, 1780) and by the nematodes Passalurus ambiguus (Rudolphi, 1819), Vianella fariasi (Travassos, 1915), Longistriata perfida Travassos, 1943, Trichostrongylus retortaeformis (Zeder, 1800). The scope of the present investigation is to survey the parasites infecting these hosts, commonly used as laboratory animal models in scientific research and supply figurative data on the helminths in order to provide their easy identification, since the presence of autochthonous parasite burdens, if undetected or misinterpreted, can alter the final results of experimental assays, mainly those related to immunological approaches, when cross-reactions can occur.