Intestinal parasites in child and youth populations of Argentina: Environmental factors determining geographic distribution.

The transmission of intestinal parasites is generally considered to be "mediated by the environment" which suggests that they are particularly sensitive to the changes that occur in it. The aim of the present study was to evaluate the environmental variables that act as risk factors for intestinal parasitosis in children and youths in Argentina. The association between environmental variables related to temperature, precipitation and soil and parasitosis found in children and youths from different provinces was evaluated, including land use/cover classes obtained from satellite images. Of the total population analyzed, 66.9% of the participants were parasitized. The total number of identified parasite species was 17 and the most prevalent were Blastocystis sp. (42.2%), Enterobius vermicularis (33.6%) and Giardia lamblia (17.0%). Infection by protozoa, and by G. lamblia in particular, was greater when the mean summer temperature was higher (OR=1.2 for both). Blastocystis sp. and geohelminths were greater due to an increase in isothermality (OR=1.1 and 1.2, respectively). The risk of infection with Ascaris lumbricoides was associated with an increase in the temperature in the wettest quarter (OR=1.2). Hookworm infection was associated with an increase in the normalized difference vegetation index (OR=32.5). Most of participants infected with hookworms lived in areas with abundant arboreal-shrubby and agropastoral use vegetation. The heterogeneous distribution of enteric parasites is indicative of the wide environmental variability of Argentina.

Morphological and molecular characterization of Bertiella sp. (Cestoda, Anoplocephalidae) infection in a human and howler monkeys in Argentina.

Bertiella sp. is a typical parasite in non-human primates and only a few cases of bertiellosis have been reported in humans. We present a new case study of bertiellosis in a 42-year-old woman caretaker of howler monkeys in a wild rehabilitation center in Argentina. Bertiella sp. infection was also diagnosed in the monkeys. Proglottids and feces were collected from the caretaker and monkeys; the samples were submitted for parasitological examination by morphological characterization and molecular identification using both nuclear (18S and ITS1-5.8-ITS2 rDNA) and mitochondrial (cox1) markers. Morphological and molecular data were consistent and allowed the classification of the specimen to the genus level. The analyses also showed the presence of cysts of Giardia lamblia and oocysts of Cryptosporidium spp. in howler monkeys, and cysts of Blastocystis sp. in both the caretaker and monkeys. This study recorded the fourth case of bertiellosis in a human host from Argentina and the eighth case in South America. Moreover, this is the first study that compares the morphological and molecular features of Bertiella sp. found in both a human and monkeys from the same geographical region. These results suggest that the cohabitation between humans and monkeys increases the opportunities of infection by Bertiella sp. and other potential zoonotic parasites.

Formalin-ethyl acetate concentration, FLOTAC Pellet and anal swab techniques for the diagnosis of intestinal parasites.

The aim of this study was to compare formalin-ethyl acetate concentration and FLOTAC Pellet techniques for the diagnosis of intestinal parasites in human stool samples. The anal swab method was used for the specific detection of Enterobius vermicularis. The study was performed in children and youth from Puerto Madryn (South Argentina). A total of 174 individuals were examined using the formalin-ethyl acetate concentration technique (FECT), the FLOTAC Pellet technique with saturated sodium chloride and zinc sulphate flotation solutions and anal swabs. The performance of copromicroscopic techniques was evaluated according to sensitivity, negative predictive value and Kappa index. Overall, 39.1% of the individuals were parasitised. The most prevalent species was Blastocystis sp. (19%) followed by E. vermicularis (17.8%), Giardia lamblia (6.3%), Entamoeba coli (5.7%), Hymenolepis nana and Endolimax nana (1.1%). The FECT was the most sensitive technique for Blastocystis sp., G. lamblia and E. coli infections, whereas FLOTAC Pellet techniques were the most sensitive for H. nana diagnosis. Anal swabs detected the highest percentage of E. vermicularis infection. This was the first time that the FLOTAC Pellet technique was used to detect intestinal parasites in humans. The FECT continues to be a reliable method for detecting protozoa and the FLOTAC Pellet technique gains importance in the diagnosis of helminths. Anal swab test remains the method of choice for the detection of E. vermicularis. However, when comparing techniques, key factors as preservation methods, preservation times and flotation solutions should be taken into account.

A new species of Moniliformis from a Sigmodontinae rodent in Patagonia (Argentina).

The majority of species of Acanthocephala known thus far from South America have been recorded mostly in fish and wild birds. In particular, rodents in Argentina have been poorly studied for acanthocephalans. The genus Abrothrix (Sigmodontinae-Cricetidae) ranges from the Altiplano of southern Peru through the highlands of Bolivia, northern Chile, and Argentina south through Tierra del Fuego. The purpose of this paper was to study Acanthocephala species parasitizing different populations of Abrothrix from Santa Cruz province (Patagonia Argentina). Specimens of Acanthocephala were found in the small intestine of Abrothrix olivaceus, showing values of P 14.7%, IM = 2.8, and AM = 0.41. All the rodents parasitized were collected in Punta Quilla, Santa Cruz, Argentina. The specimens of Abrothrix longipilis were not parasitized. Moniliformis amini n. sp. is described with features such as the long, cylindrical, and pseudo-segmented body; proboscis receptacle double walled, outer wall with muscle fibers usually arranged spirally, and a combination of several morphometric characters, mainly the very small size of the proboscis receptacle and length of the testes and lemnisci. A marked proportion of arthropods was found in the diet of A. olivaceus, characterizing it as arthropodivorous. Possibly, a larger sampling effort and specific projects dealing with the study of acanthocephalans will shed light on several questions of the rodent-Moniliformis relationship.

[Cross-sectional study of intestinal parasitosis in child populations in Argentina]. / Estudio transversal de las parasitosis intestinales en poblaciones infantiles de Argentina.

OBJECTIVE: Determine the distribution of intestinal parasitosis in children in nine provinces representative of Argentina's mosaic of contrasting environments. METHODS: Descriptive, observational, cross-sectional study of preschool children (5 years old or under) and school-age children (6-14 years) in the provinces of Buenos Aires (sample taken between 2005 and 2013), Chubut (2010-2013), Corrientes (2012), Entre Ríos (2010-2012), Formosa (2014), La Pampa (2006), Mendoza (2008-2011), Misiones (2005-2008 and 2013), and Salta (2012-2013). Serial samples, fecal samples, and anal swabs were processed using concentration techniques. The results were analyzed by sex, age interval, and province. Frequency of parasitosis (monoparasitosis and multiple parasitoses), wealth of species, and Sørensen similarity coefficient were calculated. RESULTS: Misiones presented the highest frequency of parasitized children and Chubut the lowest (82.0% vs 38.4%; p < 0.01). The number of species was greatest in Misiones and Buenos Aires and lowest in Chubut and La Pampa. Men were parasitized more than women only in Buenos Aires. The highest frequencies were found in preschool children in Buenos Aires and schoolchildren in Mendoza and Misiones (p < 0.05). Monoparasitosis was most frequent in Chubut (67.9%) and multiple parasitosis in Formosa (69.2%). The most frequent species in the majority of provinces were Blastocystis sp. and Enterobius vermicularis. Misiones presented the highest frequency of soil-transmitted helminthes (23.3%) and Mendoza the lowest (0.6%); none were found in Chubut, La Pampa, or Salta. Buenos Aires, Formosa, and Misiones presented a similar species composition, as did Chubut and La Pampa. CONCLUSIONS: The frequency of parasitosis in Argentina corresponds to the country's complex mosaic of climatic and socioeconomic variability and shows a declining trend from north to south and from east to west.

Agricultural practices and intestinal parasites: A study of socio-environmental risk factors associated with leafy vegetable production in La Plata horticultural area, Argentina.

Foodborne diseases now represent one of the most important public health problems. The objectives were to analyze the leafy vegetables and crop soil to detect parasitic species and evaluate the factors that increase the risk of parasitic contamination in the productive units in La Plata horticultural area. The study included 261 leafy vegetable and 87 crop soil samples that were processed using washing, sedimentation, and flotation techniques. Socio-environmental characteristics and agricultural practices were surveyed, and a generalized linear model was used to assess the change in parasitic prevalence with different predictor variable. The 58.6% of leafy vegetable and 31.0% of crop soil samples contained parasitic species, the most prevalent being Blastocystis sp. and oocysts of Cryptosporidium spp. Risk factors were the limited access to health, dirt roads, children and dogs circulating in crops, field cultivation, furrow irrigation and lettuce cultivation. The high prevalence of intestinal parasites in the vegetable crops was mainly associated with the conditions of structural precariousness in the production units. These results elaborated with the participation of the population, provide valuable knowledge for the planning of epidemiological programs that include environmental health as a fundamental nexus in health campaigns.

Monoecocestus (Cestoda: Anoplocephalidae) diversity in Sigmodontinae rodents characterized by morphology and molecular methods.

This paper provides new morphological and molecular data for identifying Monoecocestus species from rodents: a) morphological update of Monoecocestus spp., b) morphological data on Anoplocephalidae taxa from Sigmodontinae rodents, c) analyses of the genetic distances between the specimens studied and other Anoplocephalidae from rodents available in GenBank, and phylogenetic inferences. A total of 25 specimens of Holochilus spp. were examined from four provinces of Argentina. Cestodes specimens were removed from the rodents small intestines. Conventional studies were used for the morphological and molecular analysis. Four taxa of Monoecocestus were identified. Monoecocestus threlkeldi was identified as first record in Holochilus chacarius and from Argentina. Molecular and morphological aspects of Monoecocestus sp.1, Monoecocestus sp.2 and Monoecocestus sp.3 were described. Specimens belonging to the genus Monoecocestus may represent closely related species, demonstrating the importance of using integrative taxonomic approaches to understand biological diversity. The continuity of the studies on Anoplocephalidae will allows to advance in investigation of molecular analyses and ecological aspects that determine parasite-host-environment relationship.

Hymenolepidid cestodes: Diversity, morphological and molecular characterization of a new species, and phylogeny of parasitic species of rodents from North and South America.

Rodents are hosts of a wide diversity of cestodes. Fifteen genera included in the family Hymenolepididae parasitize rodents, and only four of these genera have been recorded from the Neotropical region. The purpose of this paper is to update species of Hymenolepididae from rodents, describe a new species of Hymenolepis based on morphological and molecular characterization (ITS1 rDNA and cox1 mtDNA), comparing the features among the species from North and South American rodents, and provide phylogenetic inferences of Hymenolepididae from rodents based on sequences available in the GenBank. Rodents were collected in the Parque Provincial Ernesto Tornquist, Buenos Aires, Argentina. Hymenolepis ivanovae n. sp. differs from other Hymenolepis species registered from North and South American rodents by body size, scolex, suckers, cirrus sac, cirrus, testes, and eggs, among others. Comparative morphometric data for Hymenolepis species from North and South American rodents is provided. Molecular analyses place H. ivanovae n. sp. within the genus Hymenolepis with strong support, and show it close to species of zoonotic importance. The new species is the first species of Hymenolepis described from Sigmodontinae rodents.

Rodentolepis microstoma isolated from different species of Sigmodontinae rodents (Rodentia: Cricetidae) in the Cuenca del Plata, Argentina: Morphological aspects and molecular characterization.

The purpose of this paper was to study specimens of the genus Rodentolepis isolated from eight species of Sigmodontinae rodents (Rodentia: Cricetidae) from six provinces in the Cuenca del Plata, Argentina, based on morphological, morphometric and molecular characteristics (ITS1 rDNA and cox1 mtDNA). The genetic distances among studied specimens and other Hymenolepididae from rodents available in the GenBank were analyzed and phylogenetic inferences were provided. A total of 955 specimens of Sigmodontinae rodents were examined from seven localities of six provinces in the Cuenca del Plata region in Argentina. Tapeworms were removed from the rodents' small intestines. Conventional studies were used for the morphological and molecular analysis. Specimens of R. microstoma were identified. An amended diagnosis and detailed morphological description of this species is provided. The molecular analyses showed that the specimens studied form the same clade as that of R. microstoma previously studied from other hosts and regions. The genetic polymorphisms of R. microstoma observed corresponded to different groups of species hosts and regions. Moreover, eight species of sigmodontine rodents and 33 localities from the Cuenca del Plata region in Argentina constitute new host and geographical records. This study shows the importance of using integrative taxonomic approaches that combine morphological and molecular characters to understand biological diversity. Moreover, the discovery of R. microstoma in humans suggests the importance of further studies on this zoonotic cestode. This study provides important data on the taxonomy and distribution of R. microstoma to advance knowledge of the transmission dynamics of this parasite.

Prevalence of Human Intestinal Entamoeba spp. in the Americas: A Systematic Review and Meta-Analysis, 1990-2022.

Among the seven species of Entamoeba known to infect humans, E. histolytica is widely recognized as a pathogen. It is reported that Entamoeba infections are common in the developing world, but rare in developed countries. The best way to diagnose these protozoan parasites is to detect antigens or DNA in the stool. This study aimed to review the prevalence, distribution, and diagnosis methods of Entamoeba spp. infecting humans in the Americas between 1990 and 2022. A systematic review and meta-analysis were performed, including 227 studies on Entamoeba infections from 30 out of 35 American countries. The pooled prevalence of each species of Entamoeba was calculated using the random-effects model. The assignment of Entamoeba species was mainly performed by microscopy. The most widely distributed and prevalent species was E. coli (21.0%). Of the studies, 49% could not differentiate the species of the Entamoeba complex. The pathogenic species E. histolytica was distributed among 22 out of 30 American countries studied, with a pooled prevalence of 9%. Molecular data on Entamoeba species are still scarce. This is the first study that reviewed and summarized data on the prevalence of this protozoan genera among American countries.

Helminths of the kelp gull, Larus dominicanus, from the northern Patagonian coast.

The helminth community of Larus dominicanus (Charadriiformes) is reported from Península Valdés, on the Patagonian coast, Argentina. From March 2000 to April 2004, 29 kelp gulls were collected and dissected. All the birds were parasitized by at least 2 of 18 parasite species: 2 cestodes (1 Tetrabothriidae, 1 Dilepididae), 10 trematodes (2 Echinostomatidae, 3 Microphallidae, 2 Gymnophallidae, 1 Philophthalmidae, 1 Dicrocoeliidae, 1 Diplostomatidae), 4 nematodes (2 Acuariidae, 1 Capillaridae, 1 Anisakidae), and 2 acanthocephalans (Polymorphidae). The mean intensity was 3,204 parasites per host, and all helminths parasitized the gastrointestinal tract or associated glands. The helminth community of L. dominicanus on the Peninsula Valdés coast seems to be richer than those reported by previous authors in other localities in Argentina. This could be due to a greater diversity in prey items available. Nine species are recorded for the first time from the kelp gull and seven species are recorded for the first time from Argentina.

Hassalstrongylus dollfusi (Nematoda, Heligmonellidae): rediscovery in native South American rodents, six decades after its description.

Hassalstrongylus dollfusi (Díaz-Ungría, 1963) Durette-Desset, 1971 was described in a wild house mouse, Mus musculus, from Venezuela and, since then, has never been reported again in the type host or in any other host. In this work, specimens assignable to H. dollfusi were found at 10 localities in Northeast Argentina, in five species of sigmodontine rodents. The nematodes were attributed to H. dollfusi based on diagnostic characters such as: synlophe with 22-31 subequal ridges; in males, hypertrophy of right ray 4 of the male bursa, thickening of the dorsal ray and bases of rays 8, distal tip of the spicules bent and spoon shaped; and, in females, presence of subventral postvulvar alae supported by hypertrophied struts. The new host recorded are: Oligoryzomys fornesi, O. flavescens, O. nigripes, Holochilus chacarius and Akodon azarae. The parasite showed a strong preference for host species of Oligoryzomys, which appear to act as primary hosts. The parasite could be present, parasitizing different species of Oligoryzomys, in a geographic area from the type locality in Venezuela southward to north Corrientes in Argentina. It has not been reported from populations of Oligoryzomys spp. of the Argentinean and Brazilian Atlantic Forest, nor south of 28° S, which may be explained by constraints in the environmental conditions required by the free-living stages of the parasite. This study provides the first identification and redescription of H. dollfusi in southern South America, from autochthonous hosts, six decades after its description.

TITLE: Hassalstrongylus dollfusi (Nematoda, Heligmonellidae) : redécouverte chez des rongeurs autochtones d'Amérique du Sud, six décennies après sa description. ABSTRACT: Hassalstrongylus dollfusi (Díaz-Ungría, 1963) Durette-Desset, 1971 a été décrit chez une souris grise sauvage, Mus musculus, au Venezuela et, depuis lors, n'a plus jamais été signalé chez l'hôte-type ni chez aucun autre hôte. Dans ce travail, des spécimens attribuables à H. dollfusi ont été trouvés dans dix localités du nord-est de l'Argentine, chez cinq espèces de rongeurs Sigmodontinae. Les nématodes ont été attribués à H. dollfusi sur la base de caractères diagnostiques tels que : synlophe avec 22­31 crêtes subégales; chez le mâle, hypertrophie de la côte 4 droite de la bourse, épaississement de la côte dorsale et des bases des côtes 8, extrémité distale des spicules recourbée et en forme de cuillère; et, chez les femelles, présence d'ailes postvulvaires subventrales à fort support cuticulaire. Les nouveaux hôtes signalés sont : Oligoryzomys fornesi, O. flavescens, O. nigripes, Holochilus chacarius et Akodon azarae. Le parasite a montré une forte préférence pour les espèces hôtes du genre Oligoryzomys, qui semblent agir comme hôtes primaires. Le parasite pourrait être présent, parasitant différentes espèces d'Oligoryzomys, dans une zone géographique allant de la localité-type au Vénézuéla vers le sud jusqu'au nord de Corrientes en Argentine. Il n'a pas été signalé dans les populations d'Oligoryzomys spp. de la Forêt Atlantique argentine et brésilienne, ni au sud de 28° S, ce qui peut s'expliquer par des contraintes dans les conditions environnementales requises par les stades libres du parasite. Cette étude fournit la première identification et redescription d'H. dollfusi dans le sud de l'Amérique du Sud, à partir d'hôtes autochtones, six décennies après sa description.

Redescription of Syphacia venteli Travassos 1937 (Nematoda: Oxyuridae) from Nectomys squamipes in Argentina and Brazil and description of a new species of Syphacia from Melanomys caliginosus in Colombia.

Syphacia venteli Travassos, Mem Inst Oswaldo Cruz 32:607-613, 1937 is redescribed on the basis of specimens recovered from the type host, Nectomys squamipes (Brants 1827), from Brazil and Argentina. Specimens determined by Quentin (Bull Mus Natl Hist Nat 2:909-925, 1969) as S. venteli from Melanomys caliginosus (Tomes 1860) in Colombia were re-studied and assigned to a new species. In both species, structures such as the shape of the cephalic plate, details and distribution of the submedian papillae and amphids, presence and absence of the lateral and cervical alae, and shape and structure of the accessory hook of the gubernaculum were studied with the light microscope and scanning electron microscope. The present survey is the first detailed study of the species S. venteli since the original description, and the first record of this species from Argentina. Moreover, the present study suggests that the validity of some host species of Syphacia should be questioned and that through of the study of deposited specimens, a more exact number of parasitized host species can be confirmed, contributing to a better understanding of host specificity in this genus.

Intestinal parasites in canine feces contaminating urban and recreational areas in Ushuaia (Argentina).

Wild and domestic dogs are important reservoir hosts of numerous intestinal parasites that represent potential infection sources for both humans and wild or other domestic animals. The aim of this study was to determine the presence, diversity, and contamination potential of intestinal parasites in dog feces contaminating urban and recreational areas in Ushuaia (Tierra del Fuego province, Argentina). A total of 80 canine fecal samples were collected from urban (playgrounds, streets, sidewalks, squares and coastal walks) and recreational areas (winter centers for raising and training sled dogs) in 2018. Samples were preserved in 5% formalin and processed using formalin-ethyl acetate sedimentation and FLOTAC dual Pellet techniques. Data were analyzed using the R software. At least one parasite species was recovered in 32.5% of the total samples examined. Of the seven parasite species detected, infection by protozoan species was higher than helminth infections (28.8% versus 8.8%). Sarcocystis sp. (20.0%), Giardia sp. (8.8%) and Cystoisospora spp. (7.5%) were the most frequent species, followed by Toxocara canis (5.0%), Echinococcus spp./Taenia spp. (2.5%), Trichuris vulpis and Uncinaria sp. (1.3% for both). Single infections (69.2%) were more frequent than coinfections with two (19.2%) and three parasite species (11.5%). This study provides the first description of the diversity and frequency of intestinal parasite species in dog feces from Ushuaia, the southernmost city in the world. The unfavorable environment of Ushuaia, characterized by low temperatures and winter snowfall, is likely to reduce parasite survivability, decreasing contamination potential. Some parasite species found are potentially zoonotic and represent an important risk for the human population and a source of infection to free-roaming pets. The results of this study revealed the need to strengthen the prevention, surveillance and control of these infections in pets, as well as to implement programs for public health education, control measures for the free-roaming canine population, and responsible pet ownership in the study area.

Parasitic risk factors in migrant horticultural families from Bolivia settled in the rural area of La Plata, Buenos Aires, Argentina.

OBJECTIVE: The aims were to diagnose intestinal parasites in migrant horticultural families in the rural area of La Plata, and assess factors that increase the risk of parasitic infection. MATERIALS AND METHODS: Serial stool samples and anal swabs of 350 individuals were processed using sedimentation and flotation techniques. Socio-sanitary and environmental characteristics were surveyed using a semi-structured questionnaire. A generalized linear model was used to assess the change in parasitic prevalence with different predictor variables. RESULTS: Of all examined individuals, 79.1% were parasitized, and 12 parasites were identified. Blastocystis sp. (58.9%), Entamoeba coli (26.3%), Enterobius vermicularis (26.0%), and Giardia lamblia (24.0%) were the most prevalent species. Risk factors were age group (<12 years), sampling site, and a basic education of parents. CONCLUSION: The high prevalence of intestinal parasites in horticultural families is associated with inadequate environmental sanitation, a limited access to education, and insufficient hygienic habits. An increase in parasitological references in integrated studies (human, animal and environmental health) would result in an understanding of the parasitic etiology, and the development of effective actions for the control of intestinal parasites.

Risk factors for intestinal parasitoses among children and youth of Buenos Aires, Argentina.

INTRODUCTION: Intestinal parasitoses affect millions of people worldwide, especially children of developing countries. In Argentina, the prevalence of these infections varies among areas according to socio-economic and climatic variability. This study aimed to evaluate the prevalence of intestinal parasitoses and risk factors in child and youth populations from neighbourhoods of La Plata (Buenos Aires province, Argentina) affected by occasional floods, including a serious flood in 2013. METHODS: Serial stool samples and anal swabs of 398 individuals were processed using techniques of sedimentation and flotation. Socio-economic variables were surveyed using a semi-structured questionnaire and the land use/cover was determined by classification of a satellite image. RESULTS: Of all examined individuals, 70.9% were parasitized by at least one of the 12 parasites identified. The most prevalent species were Blastocystis sp. (42.7%), Enterobius vermicularis (34.7%) and Giardia lamblia (17.6%). Infection risk factors included houses built with makeshift materials and dirt floors; lack of piped water and public waste collection service, bed-sharing and living in the non-urban area. >70.3% of the participants that lived within <200 m from watercourses or permanent water bodies were parasitized. CONCLUSION: This research shows that parasitic infections are still a serious public health problem and that they are strongly associated with socio-economic conditions and land use/cover. In this context, studies focused on One Health strategy are need to ensure the diagnosis and surveillance of parasitosis and to tackle zoonotic diseases as well as to encourage the development of sanitary and educational programs sustainable over time.

Digenean parasites of Sigmodontinae rodents from Argentina: a list of species, new host, and geographical records.

INTRODUCTION: Among Argentinean rodents, only one species of Muridae and seven of Cricetidae were reported as digenean hosts. Despite the available data, the taxonomic diversity of the Digenea from rodents has been little explored. An update on digeneans of Sigmodontinae rodents (Cricetidae-Muroidea) in Cuenca del Plata is provided. New host and geographical data are recorded and taxonomic and ecological data are summarized. METHODS: Rodents were collected from 11 localities in the region Cuenca del Plata, Argentina. Moreover, other unidentified specimens from four localities, deposited in the Colección de Helmintología del Museo de La Plata, were studied. Prevalence, mean intensity, and mean abundance are provided. RESULTS: Eight species of digeneans belonging to four families were identified. Twelve new geographical records for five provinces of Argentina are presented. In addition, six new host-parasite associations are reported. The information is presented in a taxonomic list for each digenean species: site of infection, host records, locality records, and comments. CONCLUSIONS: It becomes interesting to explore the diets and habits of each rodent species to understand the dispersal and transmission ability of each group of digeneans. This survey constitutes an update on digeneans of Sigmodontinae rodents in Cuenca del Plata, Argentina.

Helminth fauna of the screaming hairy armadillo Chaetophractus vellerosus from Argentina: the consequence of host isolation on parasite diversity.

Chaetophractus vellerosus in Argentina has a north-west and central distribution. An isolated population is located in the east of the Buenos Aires province, separated from the population of central Argentina by about 500 km. We compared the component community of C. vellerosus between the main population in central Argentina and the isolated population, evaluating the impact of the host isolation on parasite diversity. Sixteen species of helminths were found, namely Ancylostoma caninum, Aspidodera fasciata, Aspidodera scoleciformis, Mazzia bialata, Pterygodermatites chaetophracti, Pterygodermatites argentinensis, Strongyloides sp., Trichohelix tuberculata, Cruzia tentaculata, Cyclobulura superinae, Delicata ransomi, Macielia jorgei, Moennigia celinae, Orihelia anticlava (Nematoda), Mathevotaenia sp. (Cestoda) and Travassosia sp. (Acanthocephala). Only the first 8 species, however, were present in both populations. Prevalences and intensities of the shared species were similar. The parasite community of the isolated population, however, was less rich and diverse than that of the main population. The poor parasite community in the isolated population could have several causes: the founding population was composed of few specimens that were only infected with the most prevalent parasite species and intermediate hosts for parasites with indirect cycles were absent. In addition, coexistence with another Chlamyphoridae would have contributed to maintaining a group of species that are usual in armadillos along their distribution.

A new species of Syphacia (Nematoda: Oxyuridae) from Akodon azarae (Rodentia: Cricetidae) in Argentina.

Eight species of Syphacia (Nematoda: Oxyuridae) have been reported from South America in rodents of the Sigmodontinae, only 1 of which has been recorded in Argentina. Syphacia (Syphacia) carlitosi n. sp. is described from the ceca of Akodon azarae bibianae and Akodon azarae hunteri (Sigmodontinae: Akodontini) captured in 3 provinces in the northeast region of Argentina. The new species is differentiated principally by the shape of the cephalic plate; distribution of submedian papillae and amphids; presence, extent, and shape of cervical alae in females; absence of lateral alae; absence of deirids; spicular and gubernaculum length; shape and structure of accessory hook of gubernaculum; and distance of mamelons, excretory pore, and vulva from the anterior extremity. This is the second record of Syphacia parasitizing rodents of the tribe Akodontini.

Natural infection of the feline lungworm Aelurostrongylus abstrusus in the invasive snail Achatina fulica from Argentina.

The giant African snail Achatina fulica is an invasive mollusk native to Africa, the first record in Argentina was in Puerto Iguazú, in northeastern Argentina in 2010. Recently it was reported in Corrientes Province. This snail can act as an intermediate host of Metastrongyloidea nematodes of importance in public health as: Angiostrongylus cantonensis, Angiostrongylus costaricensis and Angiostrongylus vasorum. Taking into account the presence of A. fulica in Argentina, the objectives of this study is to assess the presence of Metastrongyloidea nematodes in this mollusk species in Puerto Iguazú, Misiones, close to the international border with Brazil and Paraguay. A total of 451 samples were collected from February 2014 to November 2015. The snails were processed using a digestion technique to recover the parasites. A total of 206 nematodes larvae were founded in the digestion solution of 10 hosts (P=2%; MA=0.5; MI=21). Third larval stage (L3) nematodes identified as Aelurostrongylus abstrusus were founded parasitizing the snails. No other larval stage was observed. This species has veterinary importance because it causes 'aelurostrongilosis', also known as feline strongyloidosis. This study constitutes the first record of a Metastrongyloidea nematode in A. fulica in Argentina and also highlights the susceptibility of this mollusk as intermediate host of other helminthes of health importance. The present study suggests that there is a need to establish an epidemiological monitoring system in order to prevent the possible installation of an infected mollusks focus.