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Background: Up to now, five cestode species have been reported infecting five hummingbird species. To date, there have been no reports of cestode infections in hummingbirds in Mexico. Methods: A Berylline hummingbird (Saucerottia beryllina) was found dead in a backyard at Toluca City, Mexico, and a window collision was assumed as the cause of death. The bird was preserved in 10% neutral buffered formalin for routine histological examination. Results: At the histological study, liver parenchymal disruption was observed. This lesion could be the result of the assume collision. No lesions were observed in other tissues examined. Conspicuous cestode structures were observed in the lumen of the small intestine. Structure of cestodes, as revealed from histological sections, suggests their position in the genus Anonchotaenia Cohn, 1900 (family Paruterinidae). Conclusion: This is the first report of intestinal cestodosis in a Berylline hummingbird (S. beryllina) in Mexico. [ABSTRACT FROM AUTHOR]

Eight specimens of Urobatis jamaicensis were collected from four localities of the Yucatan Peninsula, Mexico, of which four specimens were infected with cestodes of two new species of Acanthobothrium. Acanthobothrium garciaprietoi sp. nov. differs from congeners by a combination of characters including the size of the scolex and bothridia, length of the cephalic peduncle, length of the axial and abaxial prongs and total length of the abaxial prongs of the hooks, size of the cirrus sac and testes in mature proglottids, and the total number of proglottids. The most prominent characteristic distinguishing A. pulidofloresae sp. nov. from other species of the Atlantic Ocean/Caribbean Sea/Gulf of Mexico is the form of the scolex, which has the "clover leaf" configuration. In addition, it can be distinguished by the total length of the worm, total number of proglottids, small accessory suckers, the form of the bothridia, length of the axial and abaxial prongs and total abaxial prong length of hooks, and the number of testes. According to the current category scheme, A. garciaprietoi sp. nov. and A. pulidofloresae sp. nov., belong to categories 1 and 5, respectively. [ABSTRACT FROM AUTHOR]

Metazoan parasite communities can experience temporal structural changes related to seasonal and/or local variations in several biotic and abiotic environmental factors. However, few studies have addressed this issue in tropical regions, where changes in water temperature are less extreme than in temperate regions, so the factors or processes that can generate variations in these parasite communities are as yet unclear. We quantified and analysed the parasite communities of 421 Lutjanus peru (Nichols & Murphy, 1922) collected from Acapulco Bay in Guerrero, Mexico, over a four-year period (August 2018 to April 2021), to identify any interannual variation due to local biotic and abiotic factors influenced by natural oceanographic phenomena, such as El Niño–Southern Oscillation, or La Niña. Twenty-five metazoan parasite taxa were recovered and identified: seven Digenea species; two Monogenea; one Cestoda; one Acanthocephala; four Nematoda; and ten of Crustacea (seven Copepoda and three Isopoda). The digeneans and copepods were the best represented parasite groups. The parasite communities were characterized by a high numerical dominance of helminth larvae. Species richness at the component community level (13 to 19 species) was similar to reported richness in other Lutjanus spp. The parasite communities of L. peru had a high variability in species composition, but low aggregate variability (e.g. species diversity), suggesting that structure of these communities may be quite stable over time. A clear interannual variation pattern was not observed, suggesting that parasite species of this host may respond differently to variations in environmental factors. Interannual variations were possibly caused by a combination of biotic (i.e. host feeding behaviour and body size) and local abiotic factors (influenced by climatic anomalies) which generated notable changes in the infection levels of several component species. [ABSTRACT FROM AUTHOR]

Sixty-eight lizards representing 4 species (Aspidoscelis mexicanus, Sceloporus horridus, Sceloporus ochoterenae, and Urosaurus bicarinatus) collected from the locality of Santiago Tamazola in the Mixteca Region of Oaxaca, Mexico were examined for gastrointestinal helminths. One species of Cestoda, Mesocestoides sp. (tetrathyridium larvae), and 2 species of Nematoda, Physaloptera retusa and Spauligodon garciaprietoi were found. Physaloptera retusa had the highest prevalence (85%) in S. horridus and was found parasitizing all 4 lizard species, and S. garciaprietoi had the most numerous helminth (n = 626) in A. mexicanus. The helminths are generalist and have indirect life cycles with the exception of S. garciaprietoi. We provided new host and distribution records for the 3 helminth species (Mesocestoides sp., P. retusa, and S. garciaprietoi) and present the first helminth reports for S. horridus, S. ochoterenae, and U. bicarinatus. Further, Mesocestoides sp. tetrathyridia is reported for the first time in Oaxaca State. This work contributes to the helminth fauna associated with lizards from Mexico. [ABSTRACT FROM AUTHOR]

The black rat Rattus rattus and the house mouse Mus musculus are two commensal rodent species that harbour and shed zoonotic pathogens, including helminths. The aim of this survey was to study the helminth community and the patterns of infections in R. rattus and M. musculus from two Mayan communities in Mexico. Gastrointestinal helminths were isolated from 322 M. musculus and 124 R. rattus , including Gongylonema neoplasticum , Hassalstrongylus aduncus , Hassalstrongylus musculi , Hydatigera taeniaeformis metacestode, Hymenolepis diminuta , Nippostrongylus brasiliensis , Oligacanthorhynchidae gen. sp., Syphacia muris , Syphacia obvelata , Rodentolepis microstoma and Trichuris muris. The overall richness of helminths was seven in R. rattus and six in M. musculus. The results of generalized linear models showed that juvenile rodents had lower probabilities of being infected with G. neoplasticum , H. taeniaeformis and H. musculi than adult rodents. A positive association between the prevalence of S. muris and rat abundance was found. The intensity of infection with S. muris was higher in the rainy season than in the dry season; the opposite result was found for H. musculi infection. Male R. rattus harboured more S. muris specimens. The intensity of infection with T. muris was inversely associated with mouse abundance. The presence of the zoonotic H. diminuta , as well as H. taeniaeformis and R. microstoma in rodent populations indicates that there is risk of transmission, and that their entire life cycle occurs in the study area. [ABSTRACT FROM AUTHOR]

Objetivo: Determinar las diferencias en la duración de la fase preclínica de la neurocisticercosis, en relación con la localización del parásito. Antecedentes: La neurocisticercosis (NC) es una enfermedad heterogénea (síntomas, tratamiento, pronóstico), dependiendo principalmente de la localización de los parásitos (parenquimatoso (PAR), intraventricular (IV), y subaracnoidea (SA)). Este aspecto también parece modular el tiempo entre infección y síntomas que puede ser muy prolongado en ciertas localizaciones. (protocolo número 07/17) Métodos: Se reclutaron 99 pacientes con diagnóstico de neurocisticercosis definitiva en fase vesicular, 56 SA, 19 IV y 24 PAR. Se aplicó un cuestionario estandarizado para determinar los factores de riesgo clásicos que presentaban a diferentes tiempos antes del diagnóstico. Se estableció un sistema de puntuación basado en el número de factores de riesgo a los cuales los pacientes eran expuestos, se evaluó su frecuencia a los diferentes tiempos considerados y se compararon los resultados entre los pacientes afectados por NC PAR, NC IV y NC SA. Los análisis estadísticos se realizaron por medio de regresión lineal, y utilizando las pruebas U de Mann-Whitney, Kruskall Wallis, y Chi-cuadrado. Resultados: 43 mujeres y 56 hombres fueron incluidos. La proporción hombres/mujeres y las edades fueron similares entre los 3 grupos considerados. Hubo una disminución altamente significativa de la exposición a los factores de riesgo con el tiempo cuando todos los pacientes eran incluidos o cuando consideramos solamente los pacientes afectados por NC SA (p<0.0001 en ambos casos). Esta tendencia fue igualmente significativa cuando los pacientes afectados por NC IV y PAR fueron considerados (p=0.011 en ambos casos) aunque menos pronunciado. Particularmente, 5 años antes del diagnóstico, los pacientes con NC PAR y NC IV presentaban una exposición significativamente más alta que los pacientes con NC SA (p=0.043). (Figura 1) Conclusiones: La exposición a los factores de riesgos "clásicos" de la NC ha disminuido de manera significativa durante los últimos 20/30 años en México, lo que conlleva una disminución de la incidencia de la infección, principalmente de la NC PAR e IV. En efecto, en estas formas la fase preclínica es corta. Las características anatómicas de los diferentes compartimentos afectados explican las diferencias de duración de la fase preclínica. [ABSTRACT FROM AUTHOR]

Fasciola hepatica is a helminth parasite that causes huge economic losses to the livestock industry worldwide. Fasciolosis is an emerging foodborne zoonotic disease that affects both humans and grazing animals. This study investigated the associations between climatic/environmental factors (derived from satellite data) and management factors affecting the spatial distribution of this liver fluke in cattle herds across different climate zones in three Mexican states. A bulk-tank milk (BTM) IgG1 enzyme-linked immunosorbent assay (ELISA) test was used to detect F. hepatica infection levels of 717 cattle herds between January and April 2015. Management data were collected from the farms by questionnaire. The parasite's overall herd prevalence and mean optical density ratio (ODR) were 62.76% and 0.67, respectively. The presence of clustered F. hepatica infections was studied using the spatial scan statistic. Three marked clusters in the spatial distribution of the parasite were observed. Logistic regression was used to test three models of potential statistical association from the ELISA results using climatic, environmental and management variables. The final model based on climatic/environmental and management variables included the following factors: rainfall, elevation, proportion of grazed grass in the diet, contact with other herds, herd size, parasite control use and education level as significant predictors. Geostatistical kriging was applied to generate a risk map for the presence of parasites in dairy herds in Mexico. In conclusion, the spatial distribution of F. hepatica in Mexican cattle herds is influenced by multifactorial effects and should be considered in developing regionally adapted control measures. [ABSTRACT FROM AUTHOR]

Copyright of Therya is the property of Asociacion Mexicana de Mastozoologia, A. C. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Neurocysticercosis, caused by the larval stage of Taenia solium , is a life-threatening condition and the most severe form of the disease. Yet, despite being a required link in the parasite life cycle, tapeworm carriers are rarely reported. This study is aimed to find and evaluate T. solium carriers, describing some characteristics of these patients and the treatment. Taeniasis cases were searched for in various Mexican states from 1983 to 2016. Previous informed consent, tapeworm-carrier patients were administered with niclosamide and a saline purge. Parasite specimens were recovered and identified, both morphologically and by PCR. From 117 treated patients, Taenia sp. specimens were obtained from 46 subjects (47.8%). From these, complete parasites were recovered from 42 (90.5%), and only detached proglottids from 4 patients. Cases were more frequent in Morelos, Chiapas, and Guerrero. More than one adult cestode was recovered from 4 patients (9.5%). To improve treatment efficacy and adherence, the drug was administered in late afternoon, resulting a high recovery yield of complete parasites (90.5%). The success rate of deworming campaigns in areas of Mexico and the world that are endemic for Taenia sp. could be improved by administering the treatment at times that do not interfere with the patients' daily activities, and national health authorities could apply this simple strategy to help eradication efforts in endemic areas. The detection of carriers will only be possible through the coordinated efforts of public and private health services, a better education of the general population to improve self-detection, and adequate, personalized diagnostic procedures for suspect cases. [Display omitted] • Despite being necessary for the parasite life cycle, taenia carriers are rare. • Carriers of adult Taenia sp. specimens were actively sought. • More than one taenia per patient was recovered in four cases. • Drug administration in the late afternoon improved treatment adherence. [ABSTRACT FROM AUTHOR]

Copyright of Therya is the property of Asociacion Mexicana de Mastozoologia, A. C. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: To present a retrospective study from patients with spinal cysticercosis (SC), diagnosed within the last 30 years in Mexican and Indian neurological referral centers.Methods: This is a retrospective and comparative study of the clinical and radiological profile between Mexican and Indian patients with spinal neurocysticercosis during a 30-year period and a review of the literature during the same period.Results: Twenty-seven SC patients were included: 19 from Mexico and 8 from India. SC presented predominantly with motor symptoms (21/27 patients): paraparesis and paraplegia were the most common signs; one-third of patients presented sphincter dysfunction. Imaging studies showed that parasites in vesicular stage were more frequent in patients from Mexico, while degenerative stages predominated in India. Association of subarachnoid cysticerci and hydrocephalus was observed only in Mexican patients.Conclusions: Despite the limitations of this study, the collected information supports the existence of differences in the clinical and radiological traits of SC patients between Asian and Latin-American hospitals. The possible biological factors that may underlie these differences are discussed. [ABSTRACT FROM AUTHOR]

We collected 21 individuals of the shovel-headed treefrog ( Diaglena spatulata), a Mexican endemic species, from the states of Colima and Jalisco. Within this sample we documented the presence of the following parasites and commensals: a cestode (plerocercoid) of the order Proteocephalidea; adult nematodes of Aplectana, Cosmocercella diaglenae, Parapharyngodon chamelensis, and Physalopteroides bahamensis; and juvenile oligochaetes of Dero ( Allodero). Our results extend the geographical distribution of C. diaglenae and P. chamelensis in Mexico and add four new records of species inhabiting this host. Additionally we recorded P. bahamensis and Dero ( Allodero) for the first time in Mexico. Parapharyngodon chamelensis exhibited the highest infection levels, and levels were significantly higher in Jalisco than in Colima. The composition and abundance of parasites and commensals found in D. spatulata reflect the mainly insectivorous diet of this treefrog and show that aquatic habits exhibited during the breeding season (e.g., in temporary ponds) may play an important role in some of the infections. Recolectamos 21 individuos de la rana pico de pato ( Diaglena spatulata), una especie endémica de México, en los estados de Colima y Jalisco. Dentro de la muestra detectamos la presencia de los siguientes parásitos y comensales: un céstodo (plerocercoide) del orden Proteocephalidea; nemátodos adultos de Aplectana, Cosmocercella diaglenae, Parapharyngodon chamelensis y Physalopteroides bahamensis; y oligoquetos juveniles de Dero ( Allodero). Nuestros resultados amplían la distribución geográfica de C. diaglenae y P. chamelensis en México y añaden cuatro nuevos registros de especies que habitan en el hospedero. Adicionalmente reportamos por primera vez la presencia de P. bahamensis y Dero ( Allodero) en México. Parapharyngodon chamelensis exhibió los niveles de infección más altos y éstos fueron significativamente mayores en Jalisco que en Colima. La composición y abundancia de los parásitos y comensales encontrados en D. spatulata reflejan la dieta principalmente insectívora de esta rana y muestran que los hábitos acuáticos exhibidos durante la época reproductiva (e.g., en cuerpos de agua temporales) pueden jugar un papel importante en algunas de las infecciones. [ABSTRACT FROM AUTHOR]

A total of 802 individuals of Lutjanus guttatus (Steindachner, 1869) specimens were collected over a 10-year period (August 2012 to February 2021) from four locations on the south-central Pacific coast of Mexico. Their parasite communities were quantified and analyzed to determine if they experience significant spatial and inter-annual variations. Thirty-two taxa of metazoan parasite were recovered and identified: four species of Digenea, four Monogenea, one Cestoda, two Acanthocephala, seven Nematoda, one Hirudinea, and nine of Crustacea (six Copepoda, and three Isopoda). Species richness was greatest among the digenean group, which represented 25% of the total species recovered, followed by the nematodes (22% of total species). Species richness at the component community level (10 to 20 species) was similar to reported richness in other Lutjanus spp. The component communities and infracommunities exhibited a similar pattern: low species richness and diversity, and dominance by a single species, mainly the monogenean Haliotrematoides guttati. Parasite community structure and species composition varied through the years, as well as between sampling locations. Variations were possibly caused by a combination of biotic and abiotic factors which generated notable changes in the infection levels of several component species. However, the similarity in the parasite species composition was high locally for short-term periods (one or two years). This result, therefore, suggests that parasite communities of L. guttatus may be more predictable locally, but only for short-term periods. [Display omitted] [ABSTRACT FROM AUTHOR]

Copyright of Revista Mexicana de Biodiversidad is the property of Universidad Nacional Autonoma de Mexico, Instituto de Biologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Neurocysticercosis results from the infestation of the central nervous system with invading tapeworm larvae. Though uncommon in the US prior to 1965, new cases are currently being diagnosed at an unprecedented rate. Drawing on environmental health, intervention and risk data retrieved from standard/alternative databases and in-country sources, we present an update and summary of modifiable risk factors and field-tested primary prevention measures. While points of intervention, subpopulations at risk and overall magnitude of the problem are addressed, particular attention is paid to defining risk reduction measures that can be adopted by individuals and high risk groups in the near-term to interrupt or eliminate pathways of exposure leading to disease transmission. Though global eradication is not attainable in the near future, effective preventative measures exist and should be taken now by international travellers and workers, US/foreign government agencies, and individuals living in endemic regions to reduce human suffering. [ABSTRACT FROM AUTHOR]

The article presents a study which examined helminth parasites found in 78 spotted ground squirrels, Xerospermophilus spilosoma in central Mexico. From 60 hosts helminth parasites including Acanthocephala, Nematoda and Cestoda, 18 hosts were negative for parasites. The parasites found included Dermatoxys veligera, Heteromyoxyuris deserti, Mastophorus dipodomis, Moniliforms clarki, Protospira ascaroidea and S. peromysci.

Two male desert shrews, Notiosorex c. crawfordi (Coues), representing two localities from the Central Desert, Valle de los Cirios, of Baja California, México, were studied by light microscopic techniques to delineate baseline morphological criteria. The specimens were made into study skins in the field which eliminated the skulls and skins for possible study by microscopic techniques. A general survey was made of the major organ systems: muscular, skeletal and body wall; hematopoetic; central nervous; gastrointestinal; genito-urinary; endocrine; cardiovascular and respiratory. The presence of shoulder glands is described although their function is not known. The animals were parasitized by tapeworms (Cestoda: Hymenolepididae) and nematodes (Nemata). [ABSTRACT FROM AUTHOR]

Objetivo: generar una nueva estrategia proteómica y bioinformática para identificar y caracterizar proteínas de secreción de cisticercos de Taenia solium. Antecedentes: la neurocisticercosis es causada por el establecimiento del cisticerco de T. solium en el sistema nervioso central. El cisticerco secreta proteínas en su metabolismo, para favorecer su establecimiento y para evadir la respuesta inmune. Por ello, la caracterización de las proteínas de secreción es vital para diagnosticar la enfermedad y para identificar blancos vacunales y terapéuticos. Sin embargo, las proteínas de secreción se obtienen en bajas concentraciones, lo que impide conocer su secuencia por espectrometría de masas. En este trabajo se propone una nueva estrategia para identificar y caracterizar proteínas del cisticerco de T. solium. Métodos: Se combinaron dos estrategias, una proteómica y una bioinformática. En la primera, se obtuvieron proteínas de secreción de cultivos cisticercos provenientes de cinco cerdos infectados naturalmente. Las proteínas de cada cultivo se separaron con geles 2D y se analizaron con el programa ImageMaster para determinar su punto isoeléctrico y peso molecular. Por otro lado, en la segunda estrategia se usó el genoma publicado de T. solium para predecir la secuencia proteica de cada spot identificado en los geles 2D según su punto isoeléctrico y su peso molecular. Las secuencias permitieron identificar proteínas conservadas y diferenciales entre cultivos. La funcionalidad de las proteínas se determinó con los programas BlastKOALA y KOBrite. Resultados: en total se identificaron 108 proteínas conservadas y 186 diferenciales en los cinco cultivos analizados. Entre las proteínas predichas con nuestra estrategia identificamos 14 que son comunes en cuatro de cada cinco cultivos de cisticercos, y podrían usarse para diseñar vacunas o métodos de diagnóstico para la neurocisticercosis. El análisis bioinformático de las secuencias predichas mostró que el parásito libera proteínas mediante un mecanismo exosome-like, lo que podría ser de interés biológico. Conclusiones: la combinación de estrategias proteómicas y bioinformáticas permitió analizar proteínas de secreción del cisticerco sin necesidad de secuenciación por espectrometría de masas. La caracterización funcional de las proteínas conservadas mejora nuestro conocimiento sobre el rol de las proteínas de secreción en la cisticercosis. [ABSTRACT FROM AUTHOR]

Taenia solium and T. saginata are zoonotic tapeworms of substantial medical and economic importance. Although human taeniasis is widely recognised as an endemic problem in Mexico, its presence in the United States is poorly understood. The first population-based study to estimate the prevalence of human infection with Taenia tapeworms along the Texas–Mexico border has recently been conducted. Households were interviewed in the Texan city of El Paso and in the neighbouring Ciudad Juárez, in Mexico. Faecal samples from household members were then checked for Taenia eggs by flotation and/or for Taenia copro-antigens in an ELISA. The overall prevalence of taeniasis in this border region was found to be 3% but, compared with the residents of Juárez, El Paso residents were 8.6-fold more likely to be tapeworm carriers. The interviews revealed some important differences between the two study sites, particularly the more frequent use of anthelminthic drugs on the Mexican side of the border. These findings have implications in terms of the planning of effective health-education campaigns to decrease the prevalence of taeniasis in the human populations along the Texas–Mexico border. [ABSTRACT FROM AUTHOR]

Distribution records of 152 adult helminth taxa parasites of freshwater fishes in Mexico were analysed to determine areas of high richness and endemism. Distribution maps were prepared for each taxon and overlaid onto a map of Mexico divided into 1 × 1 degree grid-cells. Richness was determined by counting recorded helminth species in each grid-cell. A corrected weighted endemism index was calculated for each grid-cell, and the relationship between richness and endemicity was analysed with an Olmstead–Tukey corner test of association. Five areas of high richness and endemism were identified: (1) Los Tuxtlas and the Papaloapan river basin, on the Gulf of Mexico; (2) the Grijalva-Usumacinta basin near the Gulf of Mexico coastal plain; (3) the Yucatan Peninsula; (4) the Sierra de Manantlán Biosphere Reserve in western Mexico; and (5) the Pátzcuaro lake, in central Mexico. The distribution of richness and endemism of helminth parasites of freshwater fishes in Mexico is congruent with distributional patterns described for other freshwater taxa in Mexico. Patterns of richness and/or endemism in the studied areas can be explained by the ichthyological composition of their bodies of water. The present study establishes an objective way of analysing the relationship between richness and endemicity, and suggests that helminths can make valuable contributions to regionalization of geographical areas and for identification of rich and biologically complex areas with potential for conservation of aquatic systems. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 94, 435–444. [ABSTRACT FROM AUTHOR]

We analyzed 28 digestive tracts of Rio Grande wild turkeys (Meleagris/gallopavo intermedia) of adult males donated by hunters during the game seasons (March - April) from 2000 to 2003, in the Campo Santa Maria municipality of Lampazos de Naranjo, Nuevo Leon, Mexico. There were found 462 cestodes of the species Metroliasthes lucida (Family Dilepididae). The importance of this study is to notify the possible limiting factors, of this host, present in the ecosystem, since it is a bird of hunting relevance. Little is known in Mexico on how this cestode affects his host. Macroscopic lesions were not found in the small intestine, neither some pathogenic signs associated with the presence of the parasite. As a result of the massive infestation presented in a wild turkey, it is suggested that they could cause intestinal occlusion. This is the first report of Metroliasthes lucida for Rio Grande wild turkey of Nuevo Leon, Mexico. [ABSTRACT FROM AUTHOR]

Hymenolepidid cestodes of synanthropic rodents represent a risk for public health. In order to describe the occurrence of hymenolepidids in children and the role of rodents as a potential source of infection, we conducted a morphological and molecular survey on cestodes in two rural villages from Yucatan, Mexico. One hundred and thirty-five stool samples from children (64 from Paraíso and 71 from Xkalakdzonot), 233 Mus musculus (159 from Paraíso and 74 from Xkalakdzonot) and 125 Rattus rattus (7 from Paraíso and 118 from Xkalakdzonot) were analyzed for the presence of cestodes. Three hymenolepidid species were identified morphologically: Hymenolepis nana in 7.8% of children from Paraíso, Hymenolepis microstoma in 4.4% of M. musculus from Paraíso and Hymenolepis diminuta in 15.3% of R. rattus from Xkalakdzonot. The molecular characterization and phylogenetic analysis based on mitochondrial cytochrome c subunit 1 (CO1) gene and ribosomal internal transcribed spacer 1 (ITS1) region, confirmed the identity of the three cestodes isolated from Yucatan. Phylogeny of the CO1 gene identified intraspecific genetic differences within H. nana ranging from 0 to 5%, in H. microstoma from 0 to 0.4%, and in H. diminuta ranged from 0 to 6.5% which suggests, the presence of complex species within H. nana and H. diminuta infecting humans and rodents, as reported by other authors. Based on the morphological and molecular results, and the epidemiological evidence, infections with H. nana suggest a non-zoonotic transmission; however, the presence of H. microstoma and H. diminuta in synanthropic rodents serve as a possible source for human infection. Unlabelled Image • Eggs of H. nana were identified in 7.8% (5/64) of children. • Adult worms of H. microstoma were found in 4.4% (7/159) of M. musculus. • Adult worms of H. diminuta were identified in 15.3% (18/118) of R. rattus. • Intraspecific genetic differences within H. nana and H. diminuta were identified. [ABSTRACT FROM AUTHOR]

Cestodes collected from the spiral valves of the stingray Urotrygon sp. from the Pacific coast of Mexico were identified as Escherbothrium molinae Berman and Brooks, 1994. The first report of the species was from the Gulf of Nicoya and the Guanacaste coast, Costa Rica; this work represents the second report of the species since the original description and extends its distribution north to Acapulco, Guerrero, Mexico. [ABSTRACT FROM AUTHOR]

In order to contribute to the knowledge on helminth parasites of freshwater fishes in Mexico, the helminth fauna of the cyprinid fish Notropis moralesi was studied. The helminth species Bothriocephalus acheilognathi and Rhabdochona canadensis were recovered from 20 examined hosts. Values of prevalence, abundance and mean intensity of each infection are provided. Present work represents the first helminthological study for N. moralesi. Therefore, both helminth species recorded are new host records. This is the second report of B. acheilognathi and the first of R. canadensis for the state of Puebla. [ABSTRACT FROM AUTHOR]