Vol. 31 Nº 1

In Argentina, parasitological studies on Cricetidae rodents have been carried out mainly on nematodes. However, some research has shown that cestodes are also common components of their parasitic assemblages. In this study, Sigmodontinae rodents (Cricetidae–Muroidea) from the Cuenca del Plata, Argentina, are studied as hosts of cestodes. New host species, geographical areas, and parasitic infection parameters are provided. A total of 1675 specimens from 28 species of rodents from 67 localities were sampled for cestodes. Five taxa of cestodes belonging to three families were identified, including 20 new geographical records. In addition, nine new host-parasite associations are reported. These records help us to increase our understanding of the richness of cestodes in the region by providing a database to evaluate the effect of intrinsic and extrinsic factors on ecological indicators such as prevalence, abundance, and host specificity, among others.

Roedores Sigmodontinae (Muroidea: Cricetidae) como hospedadores de Cestoda de Argentina. En Argentina, los estudios parasitológicos en roedores Cricetidae han sido principalmente de nematodes. Sin embargo, algunas investigaciones han demostrado que los cestodes son componentes comunes de sus ensambles parasitarios. Los roedores Sigmodontinae (Cricetidae–Muroidea) de la región de la Cuenca del Plata, Argentina, son estudiados como hospedadores de cestodes. Se brindan nuevos registros hospedatorios y geográficos, y parámetros de infección parasitaria. Se examinaron 1675 especímenes pertenecientes a 28 especies de roedores de 67 localidades con el fin de hallar especímenes de cestodes. Se identificaron cinco taxones de cestodes pertenecientes a tres familias, entre los que se incluyen 20 nuevos registros geográficos. Además, se informan nueve nuevas asociaciones parásito-hospedador. Estos registros nos ayudan a aumentar nuestra comprensión de la riqueza de los cestodes en la región, y proporcionan una base de datos para evaluar el efecto de los factores intrínsecos y extrínsecos sobre los indicadores ecológicos, como prevalencia, abundancia, especificidad hospedatoria, entre otros.

The domestic dog (Canis lupus familiaris) plays a vital role in transmitting zoonotic ectoparasites and vector-borne pathogens, often being an important source of pathogens in spillover and spillback processes between domestic and wild animals. The aim of this study was to analyze the diversity and prevalence of ectoparasites and their associated bacteria, Rickettsia, Bartonella, and Mycoplasma, in dogs from urban, peri-urban, and rural environments in central Argentina. A total of 180 dogs were examined, and 308 ectoparasites were collected. Diversity and prevalence (P) for the environment were: Urban (P_total = 78%) [Ctenocephalides felis felis (P = 78.1%); Rickettsia felis (P = 25%); Bartonella sp. (P = 8.3%); Mycoplasma suis (P = 8.3%)]; Peri-urban (P_total = 83%) [C. felis felis (P = 80%); Rhipicephalus sanguineus s.l. (P = 20%); R. felis (P = 19.2%); Bartonella sp. (P = 25%); M. suis (P = 3.8%)]; Rural (P_total = 50%) [Pulex irritans (P = 45.4%); R. sanguineus s.l. (P = 15.1%); R. felis (P = 7.4%); M. suis (P = 8.7%)]. These results present new insights into bacteria distribution across environments, emphasizing the role of dogs in their circulation. Pulex irritans, a flea with the highest prevalence in foxes, exclusively found in the rural environment, supports the hypothesis that wild and domestic sympatric carnivores share ectoparasite species. The detection of M. suis for the first time in all analyzed ectoparasite species and environments raises questions regarding the potential reservoir role of dogs for this pathogen. Furthermore, it suggests that dogs infested with ectoparasites may be exposed to an unknown range of potentially invasive vector-borne pathogens. These findings reinforce the importance of parasitological and epidemiological studies in domestic mammals under the “One Health” paradigm.

Perros domésticos como hospedadores de ectoparásitos portadores de bacterias Rickettsia, Bartonella y Mycoplasma en áreas urbanas, peri-urbanas y rurales del centro de Argentina. El perro doméstico (Canis lupus familiaris) desempeña un papel fundamental en la transmisión de ectoparásitos y patógenos transmitidos por vectores, y muchas veces es una fuente importante en el proceso de traspaso de patógenos entre animales silvestres y domésticos. El objetivo de este trabajo fue analizar la diversidad y prevalencia de ectoparásitos y bacterias de los géneros Rickettsia, Bartonella y Mycoplasma en perros provenientes de ambientes urbanos, peri-urbanos y rurales del centro de Argentina. Se examinaron 180 perros, y se recolectaron 308 ectoparásitos. La diversidad y prevalencia (P) por ambiente fue: urbano (P_total = 78%) [Ctenocephalides felis felis (P = 78,1%); Rickettsia felis (P = 25%); Bartonella sp. (P = 8,3%); Mycoplasma suis (P = 8,3%)]; periurbano (P_total = 83%) [C. felis felis (P = 80%); Rhipicephalus sanguineus s. l. (P = 20%); R. felis (P = 19,2%); Bartonella sp. (P = 25%); M. suis (P = 3,8%)], y rural (P_total = 50%) [Pulex irritans (P = 45,4%); R. sanguineus s.l. (P = 15,1%); R. felis (P = 17,4%); M. suis (P = 8,7%)]. Aportamos nueva información sobre la distribución de las bacterias en distintos ambientes, y se destaca el papel del perro para su circulación. La presencia exclusiva de Pulex irritans, pulga con mayor prevalencia en zorros, en el ambiente rural, refuerza la hipótesis de que carnívoros silvestres y domésticos simpátricos comparten especies de ectoparásitos. La detección de M. suis por primera vez, en todos los ambientes y especies ectoparásitas, plantea interrogantes sobre el papel potencial del perro como reservorio de este patógeno. Además, sugiere que los perros infestados con ectoparásitos pueden estar expuestos a una variedad desconocida de patógenos transmitidos por vectores. Estos resultados refuerzan la importancia de los estudios parasitológicos y epidemiológicos en mamíferos domésticos bajo el paradigma de «Una Salud».

Rabies virus (RABV) may infect wildlife, domestic mammals, and humans worldwide, and outbreaks have been associated with population declines of wild carnivores. Although RABV infection has been considered almost invariably fatal, there has been growing evidence of non-lethal RABV exposure in wildlife. The aim of this study is to investigate the occurrence of RABV antibodies, as evidence of non-lethal exposure to the virus in free-living wild canids and felids from the Brazilian Pampa. Animals were live-trapped in three protected and two unprotected areas in Southern Brazil, and the presence of antibodies against RABV was verified by the RFFIT test. A total of 98 specimens without clinical signs of disease were live-trapped: 35 Cerdocyon thous, 23 Lycalopex gymnocercus, 29 Leopardus geoffroyi, 11 Leopardus wiedii. Thirteen out of 98 wild carnivores were considered seropositive to RABV: five C. thous, one L. gymnocercus, five L. geoffroyi, and two L. wiedii. All five localities where animals were sampled had at least one seropositive individual. The results support previous conclusions regarding the possible involvement of C. thous in the rabies ecology and expand the findings of RABV-seropositivity in free-living wildlife, representing the first record for the following species: L. gymnocercus, L. geoffroyi, and L. wiedii. Our findings also suggest that RABV circulation and non-lethal exposure in Neotropical wild carnivores may be more common than previously assumed. Furthermore, rabies and its sylvatic cycle should be taken into account in any conservation effort for wild carnivores.

Evidências de exposição não-letal ao vírus da raiva em carnívoros silvestres de vida livre no Pampa brasileiro. O vírus da Raiva (RABV) pode infectar mamíferos silvestres, domésticos e humanos em todo o mundo, e surtos têm sido associados com declínios populacionais em carnívoros silvestres. Apesar da infecção pelo RABV ser considerada invariavelmente fatal, há evidências crescentes de exposição não-letal em animais silvestres. O objetivo deste trabalho é investigar a ocorrência de anticorpos contra RABV, como evidência de exposição não-letal ao vírus em canídeos e felídeos de vida livre no Pampa brasileiro. Os animais foram capturados em três áreas de preservação e duas áreas não-protegidas do Sul do Brasil, e a presença de anticorpos contra RABV foi verificada por RFFIT. Um total de 98 espécimes sem sinais de doença foram capturados: 35 Cerdocyon thous, 23 Lycalopex gymnocercus, 29 Leopardus geoffroyi e 11 Leopardus wiedii. Treze dos 98 carnívoros silvestres foram considerados soropositivos para RABV: cinco C. thous, um L. gymnocercus, cinco L. geoffroyi, e dois L. wiedii. Todas as cinco localidades onde os animais foram amostrados apresentaram ao menos um indivíduo soropositivo. Os resultados corroboram conclusões anteriores sobre o possível envolvimento de C. thous na ecologia da raiva, e expandem os achados de soropositividade para RABV em animais silvestres, representando o primeiro registro para as seguintes espécies: L. gymnocercus, L. geoffroyi e L. wiedii. Nossos resultados também sugerem que a circulação do RABV e a exposição não-letal em carnívoros silvestres neotropicais pode ser mais comum do que previamente assumido. Outrossim, a raiva e seu ciclo silvestre devem ser levados em consideração em qualquer esforço de conservação de carnívoros silvestres.

Rickettsia includes pathogenic bacteria that commonly use mammals as reservoirs and amplifying hosts. In Colombia, the knowledge about mammals as reservoirs of these bacteria is limited, even in areas considered endemic regions for spotted fever group (SFG) rickettsiae. To identify wild mammals acting as potential reservoirs of Rickettsia spp., we collected blood from 573 individuals captured in the Orinoquia of Colombia and processed it to obtain serum (n = 351) and DNA (n = 250). The serum was evaluated using indirect immunofluorescence assays (IFA) for the detection of IgG antibodies to four SFG rickettsiae antigens (Rickettsia rickettsii, R. parkeri, R. amblyommatis, R. rhipicephali), and R. bellii of the Ancestral group (AG). We amplified a fragment of the rickettsial citrate synthase gene (gltA) to detect Rickettsia from blood samples. The IFA showed seropositivity in 122 individuals of 20 mammalian species. IgG antibodies titers to Rickettsia spp., at a cutoff of ≥ 1:64, were 70.49% in bats (n = 86), 21.31% in rodents (n = 26), 7.38% in marsupials (n = 9), and 0.82% in carnivores (n = 1). The potential antigens involved in a homologous reaction (PAIHR) were R. bellii (18.85%), R. amblyommatis (9.01%), R. rhipicephali (4.91%), R. rickettsii (4.91%), and R. parkeri (4.09%), respectively. Bats were the most seropositive hosts, with antibodies to different Rickettsia antigens. We detected Rickettsia in 2.8% of the DNA samples (n = 5) from rodents, bats, and marsupials, but we could not confirm the molecular identity of Rickettsia. The presence of antibodies indicated a possible exposure of the evaluated mammals to SFG and AG rickettsiae and supported that the Orinoco Region must be considered endemic for SFG rickettsiae.

Seroprevalencia de Rickettsia spp. en mamíferos silvestres de Arauca, región de la Orinoquia de Colombia. Rickettsia incluye bacterias patógenas que comúnmente utilizan a los mamíferos como reservorios y hospedadores amplificadores. En Colombia, el conocimiento sobre mamíferos reservorios de estas bacterias es limitado, incluso en áreas consideradas endémicas para rickettsias del grupo de las fiebres manchadas (GFM). Para identificar aquellos mamíferos silvestres que actúan como reservorios potenciales de Rickettsia spp., recolectamos muestras de sangre de 573 individuos capturados en la Orinoquia de Colombia y las procesamos para obtener suero (n = 351) y ADN (n = 250). El suero se evaluó mediante ensayos de inmunofluorescencia indirecta (IFA) para la detección de anticuerpos IgG contra cuatro antígenos de rickettsias del GFM (Rickettsia rickettsii, R. parkeri, R. amblyommatis, R. rhipicephali) y R. bellii del grupo Ancestral (GA). Además, amplificamos un fragmento del gen rickettsial citrato sintasa (gltA) para detectar Rickettsia spp. a partir de muestras de sangre total. Los resultados de IFA mostraron seropositividad en 122 individuos de 20 especies de mamíferos. Los títulos de anticuerpos IgG contra Rickettsia spp., en un punto de corte de ≥ 1:64, fueron 70,49% en murciélagos (n = 86), 21,31% en roedores (n = 26), 7,38% en marsupiales (n = 9), y 0,82% en carnívoros (n = 1). Los posibles antígenos implicados en una reacción homóloga (PAIHR) fueron R. bellii (18,85%), R. amblyommatis (9,01%), R. rhipicephali (4,91%), R. rickettsii (4,91%) y R. parkeri (4,09%), respectivamente. Los murciélagos fueron los hospedadores más seropositivos, con presencia de anticuerpos contra diferentes antígenos de Rickettsia. Detectamos Rickettsia en el 2,8% de las muestras de ADN (n = 5) de roedores, murciélagos y marsupiales, pero no fue posible confirmar la identidad molecular de estas. La presencia de anticuerpos indica una posible exposición de los mamíferos evaluados a las rickettsias del GFM y GA, y dan un soporte a que la Orinoquia debe ser considerada endémica para rickettsias del GFM.

La biota antártica está expuesta a factores estresantes que pueden afectar a la salud y el estado físico de los individuos. El análisis del sistema inmunitario permite evaluar la respuesta de los organismos ante factores del ambiente, como la presencia de patógenos, contaminantes, cambios en las condiciones ambientales y el efecto de la actividad antropogénica. El objetivo del presente estudio fue analizar el perfil leucocitario de los elefantes marinos del sur Mirounga leonina en Caleta Potter, Antártida, en dos momentos del ciclo anual, primavera y verano, y en relación con la carga parasitaria. Los muestreos se realizaron durante las campañas antárticas de 2017/2018 y se analizaron individuos juveniles, de los cuales se obtuvo sangre, se recolectaron piojos y se realizaron lavados estomacales. A partir de estas muestras se describió el perfil leucocitario, i.e. recuento total (RTL) y diferencial de leucocitos, y se determinó la presencia y ausencia del piojo Lepidophthirus macrorhini (Anoplura: Echinophthiriidae), además de la abundancia de nematodos gastrointestinales (Ascaridida: Anasakiidae). Según los resultados, ni los ectoparásitos ni los endoparásitos afectaron significativamente los valores observados de RTL. Sin embargo, este varió en función del momento del año, y fue mayor en primavera que en verano. La descripción del perfil leucocitario representa uno de los primeros aportes referidos de la colonia de elefantes marinos de Caleta Potter. Dado que los fócidos antárticos son predadores tope y centinelas del ecosistema, este estudio resulta un aporte al conocimiento del estado sanitario del elefante marino del sur en un contexto de cambios ambientales, climáticos y antropogénicos de la Antártida.

Leukocyte counts in southern elephant seals Mirounga leonina at Potter Cove, Antarctic Peninsula: does the presence of parasites have an effect? The Antarctic biota is exposed to stressful factors that can affect the health and physical condition of individuals. Analysis of the immune system allows evaluation of the response of organisms to environmental factors such as the presence of pathogens, contaminants, changes in environmental conditions, and the effects of anthropogenic activities. The aim of this study was to analyze the leukocyte profile of southern elephant seals, Mirounga leonina, in Potter Cove, Antarctica, at different times of the year, i.e., spring and summer, and its relationship with parasite burden. Juveniles were analyzed during the 2017/2018 field season. Blood samples were taken, lice were collected, and stomach washes were performed. These samples were used to describe the leukocyte profile (total and differential leukocyte counts) and to determine the presence or absence of the louse Lepidophthirus macrorhini (Anoplura: Echinophthiriidae), and the abundance of gastrointestinal nematodes (Ascaridida: Anasakiidae). The results showed that both ecto- and endoparasites did not significantly affect the observed leukocyte levels. However, these values varied according to the season, with higher values in spring than in summer. The description of the leukocyte profile is one of the first contributions to the elephant seal breeding colony at Potter Cove. Because Antarctic seals are top predators and sentinels of the ecosystem, this study may be useful for research on the health status of southern elephant seals in the current context of environmental, climatic, and anthropogenic changes in Antarctica.

El síndrome pulmonar por hantavirus (SPH) es una enfermedad viral aguda causada por miembros del género Orthohantavirus, familia Hantaviridae. En Argentina, se evidenció la circulación de diversos genotipos patógenos en diferentes roedores reservorios. Asimismo, se han identificado al menos cuatro genotipos no patógenos para humanos. En 2020 se confirmó el diagnóstico de un paciente con SPH, residente en la localidad de Colonia Montefiore (provincia de Santa Fe), sin antecedentes de viaje. El genotipo de orthohantavirus detectado en este paciente fue Alto Paraguay. Este genotipo había sido detectado anteriormente solo en Paraguay en roedores identificados como Holochilus chacarius, pero no en pacientes con SPH. Dado que en Argentina no existían registros sobre la circulación de este genotipo, se realizaron muestreos de la comunidad de roedores en los potenciales sitios de contagio del caso humano. Se capturaron 59 roedores, de los cuales se detectó un individuo de H. chacarius infectado con el genotipo Alto Paraguay. La comparación de las secuencias nucleotídicas de un fragmento de los segmentos genómicos S y M correspondientes al caso humano de SPH y al roedor H. chacarius presentaron un 100% de identidad. Estos resultados confirman la circulación de un nuevo genotipo de orthohantavirus patógeno en Argentina, y aportan evidencias de su potencial asociación con roedores de la especie H. chacarius, información de importancia para la toma de medidas de prevención.

Hantavirus pulmonary syndrome associated with the Orthohantavirus Alto Paraguay in Argentina. Human case study and potential rodent reservoir. Hantavirus pulmonary syndrome (HPS) is an acute viral illness caused by members of the genus Orthohantavirus, family Hantaviridae. In Argentina, there is evidence of the circulation of several pathogenic genotypes in diferent rodent reservoirs. In addition, at least four non-pathogenic genotypes for humans have been identified. In 2020, a patient inhabiting Colonia Montefiore (province of Santa Fe) without any travel history was diagnosed with HPS. The orthohantavirus genotype detected in the patient was Alto Paraguay. This genotype had previously been detected only in Paraguay in rodents identified as Holochilus chacarius, but not in patients with HPS. Since the circulation of this genotype was unknown in Argentina, we studied the rodent communities in rural areas near the site of the human infection case. Fifty-nine rodents were captured, and one specimen of H. chacarius proved to be infected with the Alto Paraguay genotype. The viral sequences of the rodent were compared with those of the patient, finding 100% nucleotide identity for the fragments of the S and M genomic segments. These results confirm the circulation of a new pathogenic genotype of orthohantavirus in Argentina, and provide evidence of its potential association with rodents of the species H. chacarius, important information for prevention measures.

Interaction networks can help understand how species are connected and the implications of these interactions for the ecosystem. This study aimed to identify the pattern of interaction between bats and ectoparasites in Sergipe and calculate the metrics of connectance, specialization, nesting, modularity, and centrality. This study was conducted based on host-parasite relationship data recorded in Sergipe and reported in previous studies. Connectance and specialization (H2′) were calculated using the “networklevel” and “specieslevel” functions, respectively. The NODF and QuanBiMo (Q) metrics were used to determine nesting and modularity, respectively. For centrality, relative degree (Kr), closeness centrality (CC), and betweenness centrality (BC) were determined. The connectance value (0.11) was considered high. H2′ was 0, and the complementary specialization (d’) values ranged from 0 to 1. The nesting and modularity values were 15.95 and 0.58, respectively. The highest Kr value was observed for Platyrrhinus lineatus. The highest CC value was observed for Artibeus planirostris. The highest BC values were recorded for A. planirostris and P. lineatus. High modularity, low nesting, and low connectivity have been frequently reported for antagonistic interactions, which may be due to the high specificity indices of these interactions. In this study, although the modularity value was significant, specialization was low, suggesting that the studied network has a composite topology. Thus, this study provides relevant information on the subject, highlighting the need for more studies to help understand the topology of networks.

Padrão de interação morcego-ectoparasito em áreas do nordeste do Brasil: uma abordagem de redes ecológicas. Redes de interação podem auxiliar na compreensão de como as espécies estão conectadas e as implicações dessas interações para o ecossistema. Esse estudo teve como objetivos identificar o padrão de interação entre morcegos e ectoparasitos em Sergipe e calcular as métricas de conectância, especialização, aninhamento, modularidade e centralidade. Esse estudo foi realizado a partir de dados da relação hospedeiro-parasito relatados em artigos científicos para Sergipe. A conectância e especialização (H2′) foram calculadas utilizando a função “networklevel” e “specieslevel”. Para o aninhamento, foi utilizada a métrica NODF. Para a modularidade foi utilizado o QuanBiMo (Q). Para a centralidade foi utilizado o relative degree (Kr), closeness centrality (CC) e betweenness centrality (BC). A conectância (0,11) foi considerada alta. O H2′ foi 0 e os valores de especialização complementar (d’) variaram de 0 a 1. O aninhamento foi 15,95 e a modularidade 0,58. Para a centralidade, o maior valor de Kr correspondeu a Platyrrhinus lineatus. Para a CC, o maior valor foi para Artibeus planirostris. Para a BC os maiores valores foram registrados para A. planirostris e P. lineatus. Alta modularidade, baixo aninhamento e baixa conectância são frequentemente relatadas para interações antagonistas, podendo ocorrer devido ao alto índice de especificidade das interações. Nesse estudo, apesar do valor de modularidade ter sido significativo, a especialização foi baixa. Isso pode sugerir que a rede estudada possua uma topologia composta. Assim, esse trabalho traz informações relevantes a cerca do tema, evidenciando a necessidade da realização de mais estudos que auxiliem na compreensão sobre topologia de redes.

In the Diptera order, there are two families that are obligatory parasites of bats: Streblidae and Nycteribiidae. These flies have a viviparous adenotrophic reproduction cycle and are highly dependent on roost fidelity. Studies investigating parasite-host association patterns for these groups have gained momentum and are important because bats are animals that provide significant ecological services to the environment and are sensitive to habitat alterations, which can influence the parasitism cycle. Despite the great diversity of bat species in the Amazon, little is known about the parasitic association patterns of these groups. Therefore, we aim to expand knowledge about the parasite-host relationships and parasitic indices values between bats and flies, as well as describe the Streblidae and Chiroptera communities in forest remnants within the urban perimeter of the municipality of Altamira, PA. Bats were sampled from three urban fragments within the municipality between August 2018 and July 2019. A total of 465 bat specimens and 629 ectoparasitic flies, all belonging to the Streblidae family, were sampled. Among the found infracommunities, the most frequent was Trichobius dugesioides on Carollia perspicilata, which also had the highest prevalence. There was no difference in infestation intensity values between the collection points, possibly due to similar anthropogenic influences on the environments, resulting in roost infidelity and influencing the specificity results. We found that 65% of the flies were considered nonspecific parasites, while only 25% were considered monoxenous, and Megistopoda proxima was considered oligoxenous for the genus Artibeus.

Associação entre morcegos (Mammalia: Chiroptera) e moscas de morcegos (Streblidae, Hippoboscoidea) de fragmentos urbanos na Amazônia. Na ordem Diptera, existem duas famílias que são parasitas obrigatórios de morcegos: Streblidae e Nycteribiidae. Estas moscas têm um ciclo de reprodução adenotrófico vivíparo e são altamente dependentes da fidelidade ao poleiro. Estudos investigando padrões de associação parasita-hospedeiro para esses grupos ganharam força e são importantes porque os morcegos são animais que prestam serviços ecológicos significativos ao meio ambiente e são sensíveis às alterações do habitat, que podem influenciar o ciclo do parasitismo. Apesar da grande diversidade de espécies de morcegos na Amazônia, pouco se sabe sobre os padrões de associação parasitária desses grupos. Portanto, objetivamos ampliar o conhecimento sobre as relações parasito-hospedeiro e os valores dos índices parasitários entre morcegos e moscas, bem como descrever a comunidade de Streblidae e Chiroptera em remanescentes florestais no perímetro urbano do município de Altamira-PA. Morcegos foram amostrados em três fragmentos urbanos do município, entre agosto de 2018 e julho de 2019. Foram amostrados 465 espécimes de morcegos e 629 moscas ectoparasitas, todas pertencentes à família Streblidae. Dentre as infracomunidades encontradas, a mais frequente foi Trichobius dugesioides em Carollia perspicilata, que também apresentou a maior prevalência. Não houve diferença nos valores de intensidade de infestação entre os pontos de coleta, possivelmente devido a influências antrópicas semelhantes nos ambientes, resultando em infidelidade do poleiro e influenciando nos resultados de especificidade. Constatamos que 65% das moscas foram consideradas parasitos inespecíficos, enquanto apenas 25% foram consideradas monoxenos, e Megistopoda proxima foi considerada oligoxenous para o gênero Artibeus.

Los parásitos pueden relacionarse y utilizar, con diferente intensidad, a más de una especie hospedadora. Los niveles de infección, como prevalencia e intensidad parasitaria, son más altos en el hospedador principal y más bajos en las especies hospedadoras auxiliares, y pueden representar su especialización parasitaria. Cuterebra Clark, 1815 (Insecta, Oestridae) comprende especies de moscas parásitas, cuyas larvas se alojan en el subcutáneo de roedores y otras especies de mamíferos americanos. Aunque son escasos, los estudios de parasitismo por Cuterebra bonaerensis en roedores abarcan un amplio rango geográfico en la zona central de Argentina. El presente estudio tiene como objetivos: a) estudiar la estacionalidad parasitaria de C. bonaerensis en el pedemonte de Mendoza; b) identificar las especies de pequeños mamíferos que cumplen el rol de hospedador principal y auxiliar/es; c) determinar la especificidad hospedatoria de C. bonaerensis en el ensamble de pequeños mamíferos de esa región, y d) analizar la distancia taxonómica promedio de C. bonaerensis, considerando a las especies de roedores que parasita en Argentina. Las especies parasitadas por C. bonaerensis en esta zona de la ecorregión del monte fueron Akodon oenos, A. dolores y Phyllotis vaccarum. Otoño y primavera fueron las estaciones más relevantes para la etapa parasitaria. Akodon oenos sería el hospedador principal, y A. dolores y Phyllotis vaccarum se comportarían como hospedadores auxiliares de C. bonaerensis. La especificidad hospedatoria de C. bonaerensis analizada desde las perspectivas taxonómica y ecológica sugieren una asociación con roedores de la subfamilia Sigmodontinae, en general, y una estrecha asociación con el género Akodon, en particular.

Host specificity of Cuterebra Clark, 1815 in sigmodontine rodents in central Monte Desert, Argentina. Parasites can interact and use more than one host species with different intensities. Infection levels such as parasite prevalence and intensity are highest in the main host and lowest in auxiliary host species, and may represent parasite specialization. Cuterebra Clark, 1815 (Insecta, Oestridae) includes species of flies whose larvae parasitize in the subcutaneous tissue of rodents and other species of American mammals. Although scarce, studies of parasitism by Cuterebra bonaerensis in rodents cover a wide geographic range in central Argentina. This research aimed to a) study the parasitic seasonality of C. bonaerensis in the foothills of Mendoza; b) identify the species of small mammals that play the role of main and auxiliary host(s); c) determine the host specificity of C. bonaerensis in the assemblage of small mammals from that region, and d) analyze the average taxonomic distance of C. bonaerensis considering the rodent species that it parasitizes in Argentina. The species parasitized by C. bonaerensis in this area of the Monte ecoregion were Akodon oenos, A. dolores and Phyllotis vaccarum. Autumn and spring were most relevant seasons for the parasitic stage. Akodon oenos would be the main host, while A. dolores and Phyllotis vaccarum would behave as auxiliary hosts for C. bonaerensis. The host specificity of C. bonaerensis, analyzed from the taxonomic and ecological perspectives, suggests an association with rodents of the Sigmodontinae subfamily in general and a particular association with the genus Akodon.

Wildlife is a potential source for emerging and re-emerging zoonotic diseases. Trichinella spiralis is the major etiological agent that causes Trichinella spp. infection in humans and domestic pigs, but other Trichinella species are also involved. Pigs are the most important source of Trichinella spp. infection worldwide, being their outdoor breeding, waste feeding, their exposure to wildlife and their carcasses, the documented risk factors for pig production, food security, and health. Early Trichinella spp. detection and the study of their reservoir’s competence are needed to prevent and control Trichinella spp. infection. The aims of this study were to analyze the occurrence of Trichinella spp. infection in synanthropic and non-synanthropic wild and domestic animals in rural areas, and compare Trichinella spp. infection in synanthropic and non-synanthropic wild small mammals on intensive and extensive piggeries. This is a two-year study in an endemic area of the disease. To evaluate parasite infection, we included samples from animals captured in 18 intensive and extensive piggeries and from road-killed vertebrates collected lengthwise 882 km within 13 counties along eight consecutive seasons. Trichinella spp. infection association to small mammals’ infestation levels and community composition and structure was analyzed. From a total of 697 wild and domestic animals analyzed, infected Rattus norvegicus and Didelphis albiventris individuals were found in two extensive piggeries. The parasite was not found outside piggeries. Infections were identified as T. spiralis by a Nested-Multiplex PCR. These findings showed some evidence that supports the idea that extensive farming has a higher risk of transmission of T. spiralis than intensive farming.

Infección natural de Trichinella spiralis en vertebrados silvestres y domésticos en un área endémica de triquinosis de Argentina. La fauna silvestre es una potencial fuente de enfermedades zoonóticas emergentes y reemergentes. Trichinella spiralis es el principal agente etiológico que causa la infección de Trichinella spp. en humanos y cerdos, pero también otras especies de Trichinella están involucradas. Los cerdos son la fuente más importante de infección por Trichinella spp. a nivel mundial, mientras que su cría al aire libre, la alimentación con desechos, su exposición a la fauna silvestre y sus cadáveres son los factores de riesgo conocidos para la producción porcina, la seguridad alimentaria y la salud. La detección temprana de Trichinella spp. y el estudio de la competencia de sus reservorios son necesarios para prevenir y controlar la triquinelosis. Los objetivos de este estudio fueron evaluar la ocurrencia de infección de Trichinella spp. en animales silvestres sinantrópicos y no sinantrópicos, y en animales domésticos en un área rural, y comparar la ocurrencia de infección de Trichinella spp. en pequeños mamíferos sinantrópicos y no sinantrópicos en granjas porcinas intensivas y extensivas. Este estudio de dos años se realizó en un área endémica de la enfermedad. Para evaluar la infección parasitaria, incluimos muestras de animales capturados en 18 granjas porcinas intensivas y extensivas y de vertebrados atropellados recolectados a lo largo de 882 km en 13 departamentos durante ocho estaciones consecutivas. Se analizó la asociación de la infección por Trichinella spp. con los niveles de infestación de pequeños mamíferos y la composición y estructura de la comunidad. De un total de 697 animales silvestres y domésticos analizados, se encontraron individuos infectados de Rattus norvegicus y Didelphis albiventris en dos criaderos extensivos. El parásito no se encontró fuera de las granjas porcinas. Mediante una PCR Nested-Multiplex las infecciones se identificaron como T. spiralis. Encontramos alguna evidencia que apoya la idea de que las granjas de cría extensiva de cerdos tienen un mayor riesgo para la transmisión de T. spiralis que la cría intensiva.

La regulación de abajo hacia arriba se refiere a los efectos que producen los cambios en la disponibilidad de recursos sobre los niveles superiores en una red trófica. Estos cambios pueden explicar los patrones de cambio de diversidad de especies, los cuales se han documentado previamente tanto en poblaciones de mamíferos y peces como en sus parásitos. Sin embargo, no hay evidencia previa de que estos efectos ocurran en la interacción de los murciélagos con sus ectoparásitos. El objetivo de este estudio fue evaluar si los cafetales bajo sombra (CBS) reducen la abundancia de murciélagos filostómidos y, de ser así, si esto provoca una reducción de la riqueza y abundancia relativa de sus moscas ectoparásitas (estréblidos). Capturamos murciélagos con redes de niebla en cuatro fragmentos de bosque de niebla (BN) y cuatro CBS. Los estréblidos fueron capturados y preservados en etanol al 96% a partir de la exploración exhaustiva de los murciélagos capturados. Encontramos una relación positiva entre la abundancia de murciélagos y la diversidad de estréblidos, y fue menor la riqueza y abundancia de moscas en los cafetales bajo sombra. Esto se debe a que los CBS reducen el alimento de los murciélagos y esto impacta en las moscas parásitas que dependen de ellos. Estos resultados apoyan la validez del mecanismo de abajo hacia arriba entre murciélagos filostómidos y sus estréblidos ectoparásitos. Además, sugieren que los CBS pueden reducir la diversidad de ectoparásitos de murciélagos, vía efectos de abajo hacia arriba.

The decrease in the relative abundance of bats (Phyllostomidae) reduces the diversity of their parasitic flies (Streblidae). Bottom-up regulation refers to the effects that changes in resource availability have on higher trophic levels in a food web. These changes can explain patterns of species diversity change, which have been previously documented in mammal and fish populations, as well as their parasites. However, there is no previous evidence that these effects are occurring in the interaction of bats with their ectoparasites. The objective of this work was to evaluate if shade coffee plantations (SCP) reduce the abundance of phyllostomid bats, and if so, promote a reduction in the diversity of their ectoparasitic flies. We captured bats with mist nets in four cloud forest (CF) fragments and four SCP. Streblids were captured and preserved in 96% ethanol after an exhaustive examination of the captured bats. We found a positive relationship between the abundance of bats and the richness and relative abundance of their ectoparasitic flies. The richness and abundance of streblids were lower in SCP because SCP reduces the food resources of bats. These results support the bottom-up mechanism between phyllostomids bats and ectoparasites. In addition, suggests that SCP may reduce the diversity of bat ectoparasites, via bottom-up effects.

Among South American countries, Paraguay is one of the least studied in terms of its fauna and flora. Although its small mammal fauna, including sigmodontine rodents (Cricetidae), is becoming better known, their ectoparasites are scarcely known. As part of a study on the effects of habitat fragmentation in the Interior Atlantic Forest in eastern Paraguay, multiple dimensions of terrestrial small mammals in three major reserves were surveyed. The aim of this study is to identify the ectoparasites collected on the most abundant rodents and to describe, visualize and quantify the parasite-host relationships. Ectoparasites obtained by brushing the fur of the rodents were preserved in vials with 96% ethanol. Mites were then fixed, cleared with lactophenol, and mounted between slides with Hoyer’s medium for identification with optical microscopes. Mites (Mesostigmata, Laelapidae) were the only ectoparasites collected (n = 189), from rodents (n = 22) identified as Hylaeamys megacephalus, Oligoryzomys nigripes, Akodon montensis, and A. paranaensis. Mites identified on rodent hosts varied from Androlaelaps fahrenholzi and Gigantolaelaps oudemansi on H. megacephalus; A. fahrenholzi, Gigantolaelaps wolffsohni, Mysolaelaps parvispinosus and Laelaps paulistanensis on O. nigripes; A. fahrenholzi and Androlaelaps misionalis on A. montensis; and Androlaelaps sp. and A. fahrenholzi on A. paranaensis. Except for A. fahrenholzi, the remaining laelapid species herein reported constitute the first records for Paraguay. However, these parasite-host relationships have been documented in neighboring countries. Thus, the results obtained herein are valuable as they improve the knowledge of the fauna in Paraguay and contribute to the knowledge of mite-host specificity.

Ácaros laelápidos (Mesostigmata) parásitos de roedores (Cricetidae, Sigmodontinae) del Bosque Atlántico Interior del este del Paraguay. Entre los países sudamericanos, Paraguay es uno de los menos estudiados en cuanto a su fauna y flora. Aunque su fauna de pequeños mamíferos, incluidos los roedores sigmodontinos (Cricetidae), es cada vez más conocida, sus ectoparásitos son poco conocidos. Como parte de un estudio sobre los efectos de la fragmentación del hábitat del Bosque Atlántico Interior en el este de Paraguay, se estudiaron múltiples dimensiones de pequeños mamíferos terrestres en tres reservas principales. El objetivo de este estudio es identificar los ectoparásitos recolectados en los roedores más abundantes y describir, visualizar y cuantificar las relaciones parásito-huésped. Los ectoparásitos obtenidos a partir del cepillado del pelaje de los roedores se conservaron en viales con etanol al 96%. Los ácaros se aclararon con lactofenol y se montaron en medio de Hoyer para su identificación con microscopios ópticos. Los ácaros (Mesostigmata, Laelapidae) fueron los únicos ectoparásitos recolectados (n = 189) de roedores (n = 22) identificados como Hylaeamys megacephalus, Oligoryzomys nigripes, Akodon montensis y A. paranaensis. Los ácaros identificados variaron desde Androlaelaps fahrenholzi y Gigantolaelaps oudemansi en H. megacephalus; A. fahrenholzi, Gigantolaelaps wolffsohni, Mysolaelaps parvispinosus y Laelaps paulistanensis en O. nigripes; A. fahrenholzi y Androlaelaps misionalis en A. montensis; y Androlaelaps sp. y A. fahrenholzi en A. paranaensis. Con la excepción de A. fahrenholzi, las restantes especies de laelápidos constituyen los primeros registros para Paraguay. Estas relaciones parásito-huésped se documentaron en países vecinos. Por lo tanto, los resultados obtenidos son valiosos, mejoran el conocimiento de la fauna en Paraguay y contribuyen al conocimiento de la especificidad ácaro-huésped.