Volumen y Número: Nº 1

Sección especial: Los mamíferos como hospedadores de parásitos

Association between bats (Mammalia: Chiroptera) and bat flies (Streblidae, Hippoboscoidea) from urban fragments of Amazon

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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.

Graphical abstract for the article “Association between bats (Mammalia: Chiroptera) and bat flies (Streblidae, Hippoboscoidea) from urban fragments of Amazon” (Bernardi Vieira et al., 2024)

Marsh deer (Blastocerus dichotomus) as a new host for Leptospira borgpetersenii in Argentina

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Leptospirosis is a worldwide re-emerging zoonosis caused by bacteria of the genus Leptospira. All mammals are potentially susceptible to pathogenic Leptospira, while certain species can act as reservoirs of the bacterium, whose main route of transmission is water. The marsh deer (Blastocerus dichotomus) is a wetland-dependent native cervid distributed in the Paraná-Paraguay River and influence areas. During the last decades, its populations have undergone mortality episodes of multifactorial origin. Since wetlands constitute favorable scenarios for the transmission of Leptospira, we investigated the occurrence of this agent in 12 marsh deer from the subpopulation of the Paraná Delta in Argentina, categorized as “Endangered”. DNA was extracted from urine and/or kidney samples, and characterization was performed at the species level by PCR amplification of the 16S rRNA gene. An aliquot of urine and serial dilutions of kidney macerates were seeded in a semisolid EMJH medium spiked with 5-Flurouracil, and isolation was achieved in a kidney sample. Leptospira borgpetersenii was detected in two samples (one from urine and one from kidney), constituting the first report in marsh deer. Our findings add a new species as the host of L. borgpetersenii, whose circulation in wildlife has been little studied in the region. Further studies are needed to determine the transmission patterns of this bacterium in wildlife, evaluate its pathogenicity in marsh deer and other wild species, and explore the existence of reservoirs in natural areas.

El ciervo de los pantanos (Blastocerus dichotomus) como un nuevo hospedador de Leptospira borgpetersenii en Argentina. La leptospirosis es una zoonosis reemergente extendida a nivel mundial causada por bacterias del género Leptospira. Todos los mamíferos son potencialmente susceptibles a las variantes patogénicas de Leptospira, mientras que determinadas especies pueden actuar como reservorios de la bacteria, cuya principal vía de transmisión es el agua. El ciervo de los pantanos (Blastocerus dichotomus) es un cérvido nativo dependiente de humedales que se distribuye en el corredor fluvial Paraná-Paraguay y áreas de influencia. Durante las últimas décadas, sus poblaciones atravesaron episodios de mortalidad de origen multifactorial. Dado que los humedales constituyen escenarios propicios para la transmisión de Leptospira, hemos investigado la ocurrencia de este agente en 12 ciervos de los pantanos de la subpoblación del Delta del Paraná en Argentina, categorizada como «En Peligro». Se extrajo ADN de muestras de orina o riñón, y se realizó la caracterización a nivel de especie mediante amplificación por PCR del gen 16S rARN. Una alícuota de orina y diluciones seriadas de macerados de los riñones se sembraron en un medio semisólido EMJH adicionado con 5-Flurouracilo, y se logró el aislamiento en una muestra de riñón. Se detectó Leptospira borgpetersenii en dos muestras (una de orina y otra de riñón), lo que constituye el primer informe de esta especie en ciervo de los pantanos. Nuestros hallazgos añaden una nueva especie como hospedador de L. borgpetersenii, cuya circulación en la fauna silvestre ha sido poco estudiada en la región. Se necesitan nuevos estudios para determinar los patrones de transmisión de esta bacteria en la fauna silvestre, evaluar su patogenicidad en el ciervo de los pantanos y en otras especies silvestres, y explorar la existencia de reservorios en áreas naturales.

Graphical abstract for the article “Marsh deer (Blastocerus dichotomus) as a new host for Leptospira borgpetersenii in Argentina” (Orozco et al., 2024)

Pattern of bat-ectoparasite interaction in the state of Sergipe, Brazil: an ecological networks approach

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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.

Graphical abstract for the article “Pattern of bat-ectoparasite interaction in the state of Sergipe, Brazil: an ecological networks approach” (Bezerra & Bocchiglieri, 2024)

Efecto de la fragmentación sobre la diversidad de murciélagos (Chiroptera) y estréblidos (Diptera: Streblidae) y redes de interacción en Puebla, México

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En el presente estudio se comparó la riqueza, diversidad y especialización de las redes de interacción hospedador-ectoparásito en dos ambientes contrastantes de Puebla, México. Se colocaron redes de niebla para la captura de murciélagos, y los ectoparásitos fueron colectados manualmente con pinzas entomológicas. Se registraron 188 murciélagos de 20 especies, de las cuales se colectaron 263 estréblidos de 11 especies. La riqueza y abundancia de murciélagos y estréblidos fue mayor en el bosque continuo, aunque el análisis de diversidad verdadera mostró que no existían diferencias significativas entre el sitio fragmentado y el bosque continuo. En el caso de los estréblidos, aunque la diversidad fue significativamente mayor en el bosque continuo, los valores de la carga parasitaria fueron similares en ambos sitios. Las redes de interacciones de los dos sitios fueron altamente especializadas y presentaron valores similares; no obstante, se observó un mayor número de enlaces en el bosque continuo. Estos resultados sugieren que la fragmentación aparentemente puede influir más sobre la diversidad de estréblidos que en la de sus hospedadores; esto puede deberse a que en ambos sitios los murciélagos Phyllostomidae tuvieron una mayor presencia. En los estréblidos, aunque no hay un efecto sobre la especialización producto de la especificidad de las interacciones murciélago-estréblido, sí existe una disminución en la riqueza de especies que da como resultado una disminución en el número de interacciones.

The effect of fragmentation on the diversity of bats (Chiroptera) and bat’s flies (Diptera: Streblidae) and interaction networks in Puebla, Mexico. The present study compares the richness, diversity, and specialization of host-ectoparasite interaction networks in two contrasting environments in Puebla, Mexico. Mist nets were placed to capture bats, while ectoparasites were collected manually with entomological tweezers. A total of 188 bats of 20 species were recorded, of which 263 bat Streblidae bat flies of 11 species were collected. The richness and abundance of bats and bat flies were higher in continuous forest, even though the analysis of true bat diversity showed no significant difference between the fragmented site and the continuous forest. Moreover, while there was a significant difference between sites for bat flies, there was no significant difference between sites for their parasitic loads. The interaction networks of both sites were highly specialized with similar values. However, a higher number of links were observed at the continuous forest. These results suggest that fragmentation may have a greater influence on the diversity of Streblidae flies than on the diversity of their hosts. This result may be due to the fact that Phyllostomidae bats were more common at both sites. Although there is no effect on the specialization of the bat flies due to the specificity of the bat-Streblidae interactions formed over evolutionary time, there is a decrease in species richness and, as a result, a decrease in the number of interactions.

Graphical abstract for the article “Efecto de la fragmentación sobre la diversidad de murciélagos (Chiroptera) y estréblidos (Diptera: Streblidae) y redes de interacción en Puebla, México” (Tlapaya-Romero et al., 2024)

Síndrome pulmonar por hantavirus asociado al Orthohantavirus Alto Paraguay en Argentina. Estudio del caso humano y potencial roedor reservorio

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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.

Graphical abstract for the article “Síndrome pulmonar por hantavirus asociado al Orthohantavirus Alto Paraguay en Argentina. Estudio del caso humano y potencial roedor reservorio” (Martin et al., 2024)

Native and exotic small mammals as hosts of Hydatigera taeniaeformis sensu stricto larvae on pig farms of central Argentina: a study of prevalence and phylogenetic relationships

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Small mammals, including those inhabiting human-modified habitats, transmit zoonotic diseases such as cysticercosis. This disease is caused by Cysticercus fasciolaris, the larval form of species within the Hydatigera taeniaeformis s.l. group. While the life cycle of these flatworms is well understood, certain aspects of their phylogeny remain unknown. Studies in Europe, Asia, and Africa suggest that the species Hydatigera taeniaeformis s.s. exclusively infects small mammals of the family Muridae. However, no studies have been conducted in the Americas until now. In this study, small mammals were captured on 18 pig farms in the province of Buenos Aires throughout a year. Necropsies of captured individuals were performed, and the presence of cysts was recorded. The prevalence of cysticercosis was analyzed for the entire assemblage, with species as the explanatory variables. Species-specific prevalence was also modeled, considering season and type of farm as the explanatory variables. Cysts were collected from Akodon azarae, Oligoryzomys flavescens, Rattus norvegicus, and Rattus rattus, and identified through molecular techniques, comparing their DNA sequences with those stored in GenBank for phylogenetic hypothesis. A total of 460 small mammals were analyzed, including the introduced species R. norvegicus, R. rattus and M. musculus, and the native species A. azarae, O. flavescens, Oxymycterus rufus, Didelphis albiventris, and Lutreolina crassicaudata. The prevalence of cysticercosis was similar between species, and it showed a seasonal association in R. norvegicus and A. azarae. Phylogenetic analysis confirmed the presence of Hydatigera taeniaeformis s.s. in cricetids, suggesting a recent spillover event associated with European colonization in the Americas.

Pequeños mamíferos nativos y exóticos como hospedadores de larvas de Hydatigera taeniaeformis sensu stricto en granjas porcinas del centro de Argentina: estudio de su prevalencia y relaciones filogenéticas. Los pequeños mamíferos, incluidos aquellos que habitan en hábitats modificados por la especie humana, transmiten enfermedades zoonóticas como la cisticercosis. Esta enfermedad es causada por Cysticercus fasciolaris, la forma larvaria de especies pertenecientes al complejo Hydatigera taeniaeformis s.l. Aunque se conoce bien el ciclo biológico de estos platelmintos, algunos aspectos de su filogenia aún son desconocidos. Algunos estudios realizados en Europa, Asia y África sugieren que la especie Hydatigera taeniaeformis s.s. infecta exclusivamente a pequeños mamíferos de la familia Muridae. Sin embargo, hasta ahora no se habían realizado estudios en el Continente Americano. En este estudio se capturaron pequeños mamíferos en 18 granjas porcinas de la provincia de Buenos Aires a lo largo de un año. Se realizaron necropsias de los individuos capturados y se registró la presencia de cisticercos. Se calculó y modeló la prevalencia de cisticercosis para todo el ensamble, con las especies como variables explicativas. También se modeló la prevalencia especie-específica, considerando la estación y el tipo de granja como variables explicativas. Se colectaron cisticercos de Akodon azarae, Oligoryzomys flavescens, Rattus norvegicus y Rattus rattus para su análisis filogenético, y se identificaron mediante técnicas moleculares, que compararon sus secuencias de ADN con las almacenadas en GenBank. Se analizó un total de 460 pequeños mamíferos, incluidas las especies introducidas R. norvegicus, R. rattus y M. musculus, y las especies autóctonas A. azarae, O. flavescens, Oxymycterus rufus, Didelphis albiventris y Lutreolina crassicaudata. La prevalencia de cisticercosis fue similar entre especies y mostró una asociación estacional en R. norvegicus y A. azarae. El análisis filogenético confirmó la presencia de Hydatigera taeniaeformis s.s. en cricétidos, lo que sugiere un evento de spillover reciente asociado a la colonización europea de las Américas.

Graphical abstract for the article “Native and exotic small mammals as hosts of Hydatigera taeniaeformis sensu stricto larvae on pig farms of central Argentina: a study of prevalence and phylogenetic relationships” (Alonso et al., 2024)

Conteo leucocitario del elefante marino del sur Mirounga leonina en Caleta Potter, Península Antártica. ¿Influye la presencia de parásitos?

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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.

Graphical abstract for the article “Conteo leucocitario del elefante marino del sur Mirounga leonina en Caleta Potter, Península Antártica. ¿Influye la presencia de parásitos?” (Ricca et al., 2024)

Intestinal helminth community structure of white-eared opossum (Didelphis albiventris) that inhabit rural areas of Buenos Aires, Argentina

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The white-eared opossum (Didelphis albiventris) is a neotropical marsupial that inhabits various ecoregions and highly modified environments. However, there is limited research on host-parasite interactions and the structure of helminth communities in D. albiventris. Therefore, the aim of this study is to investigate the intestinal helminths of D. albiventris inhabiting a rural area in Buenos Aires, Argentina, and assess the relationship between host age and sex, and helminth community structure. Opposums were captured in 2004 and intestines were examined to detect helminths. By analyzing 22 intestines, we identified a total of 8 978 helminths, including Cruzia tentaculata, Turgida turgida, Rhopalias coronatus, Brachylaima sp., individuals of the family Diplostomidae, and a single specimen of a cestode. Among these, C. tentaculata and R. coronatus were the most prevalent species, with C. tentaculata exhibiting the highest levels of abundance, mean intensity, and aggregation index. To assess the influence of host sex and age on parasite abundance and probability of occurrence, we conducted Generalized Linear Models. The results revealed that host juveniles had lower helminth prevalence and abundance compared to other age categories. Host sex was only significant in interaction with host age for parasite abundance in C. tentaculata and R. coronatus. Most captured juveniles relied on maternal feeding, potentially reducing exposure to consuming infected intermediate hosts with indirect life cycles. Understanding the parasite ecology of this opossum species in modified environments provides valuable information about their role at the wildlife-human interface in anthropogenic areas.

Estructura de la comunidad helmíntica intestinal de las comadrejas overas (Didelphis albiventris) que habitan áreas rurales de Buenos Aires, Argentina. La comadreja overa Didelphis albiventris es un marsupial neotropical que habita en diversas ecorregiones, y con frecuencia se halla en ambientes peridomésticos. Si bien existen estudios que describen los parásitos de D. albiventris, los que contemplan asociaciones entre estos y las características intrínsecas del hospedador son escasos. El objetivo de este estudio fue describir los helmintos intestinales de Didelphis albiventris en un área rural de Buenos Aires, y evaluar la influencia del sexo y la edad del hospedador sobre la presencia y abundancia de parásitos. Se analizaron 22 intestinos provenientes de la captura de ejemplares de D. albiventris y se realizaron Modelos Lineales Generalizados. Se hallaron 8 978 helmintos: Cruzia tentaculata, Turgida turgida, Rhopalias coronatus, Brachylaima sp.; familia Diplostomidae y un cestode. Cruzia tentaculata y R. coronatus fueron las especies más prevalentes; de ellas, C. tentaculata presentó mayor abundancia, intensidad media e índice de agregación. Los helmintos hallados son heteroxenos y fueron registrados previamente para esta especie. Los resultados indican que los individuos juveniles poseen una menor presencia y abundancia de helmintos, lo cual estaría asociado a su modo de alimentación. El sexo solo fue significativo en interacción con la edad para la abundancia de C. tentaculata y R. coronatus. Estudiar la estructura de la comunidad parasitaria de D. albiventris y los factores que la determinan proporciona información sobre su papel en el ambiente, particularmente en ambientes modificados, donde la interacción fauna silvestre-humanos es mayor. Futuros estudios que contemplen características ambientales y tamaño corporal del hospedador complementarán los resultados hallados en este estudio.

Graphical abstract for the article “Intestinal helminth community structure of white-eared opossum (Didelphis albiventris) that inhabit rural areas of Buenos Aires, Argentina” (Illia et al., 2024)

Rickettsia spp. seroprevalence in wild mammals from Arauca, Orinoquia region of Colombia

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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.

Graphical abstract for the article “Rickettsia spp. seroprevalence in wild mammals from Arauca, Orinoquia region of Colombia” (Velásquez-Guarín et al., 2024)

Review of tick species in two small synanthropic mammals, Didelphis albiventris (Lund, 1840) and Rattus rattus (Linnaeus, 1758)

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The present study aims to make a literature review, for the years between 1960 and 2022, of tick species that affect two species of small synanthropic mammals. A scientific literature review was carried out on the ticks that affect the species Didelphis albiventris (Lund, 1840) and Rattus rattus (Linnaeus, 1758), covering the years 1960 to 2022. The main countries that contributed to studies on the subject were: Brazil (N = 48), corresponding to 84% of the articles found, then Argentina, Angola, Madagascar, Sri Lanka, Australia, Italy, Singapore, the United States, and Taiwan, each contributing with one article (N = 1), representing 2% each of the articles found, totaling 16% remaining. We also observed differences between the percentages of studies on the small mammal species surveyed, with 77% carried out with the species D. albiventris, and 23% referring to R. rattus. Considering only the studies carried out in Brazil, which corresponded to 84%, Atlantic Forest and Cerrado seem to be the biomes with the most published studies, with ticks for both host species (N = 34) 47% and (N = 30) 42%, respectively. 7% (N = 5) of the studies were found for the Caatinga biome and 4% (N = 3) for the Pampa biome.

Espécies de carrapatos em dois pequenos mamíferos sinantrópicos. O presente estudo tem como objetivo fazer uma revisão de literatura, para os anos de 1960 a 2022, das espécies de carrapatos que acometem duas espécies de pequenos mamíferos sinantrópicos. Foi realizada revisão da literatura científica sobre os carrapatos que acometem as espécies Didelphis albiventris (Lund, 1840) e Rattus rattus (Linnaeus, 1758), abrangendo os anos de 1960 a 2022. Os principais países que contribuíram com estudos sobre o tema foram: Brasil (N = 48), correspondendo a 84% dos artigos encontrados; depois por Argentina, Angola, Madagascar, Sri Lanka, Austrália, Itália, Cingapura, Estados Unidos e Taiwan, cada um contribuindo com um artigo (N = 1), representando 2% cada um dos artigos encontrados, totalizando 16% restantes. Também observamos diferenças entre os percentuais de estudos sobre as espécies de pequenos mamíferos pesquisadas, com 77% realizados com a espécie D. albiventris, e 23% referentes a R. rattus. Considerando apenas os estudos realizados no Brasil, que corresponderam a 84%, Mata Atlântica e Cerrado parecem ser os biomas com mais estudos publicados, com carrapatos para ambas as espécies hospedeiras (N = 34) 47% e (N = 30) 42%, respectivamente. 7% (N = 5) dos estudos foram encontrados para o bioma Caatinga e 4% (N = 3) para o bioma Pampa.

Graphical abstract for the article “Review of tick species in two small synanthropic mammals, Didelphis albiventris (Lund, 1840) and Rattus rattus (Linnaeus, 1758)” (Oliveira et al., 2024)