Are Rattus rattus fleas invasive? Evaluation of flea communities in invasive and native rodents in Chile.

Co-invasion, characterized by the simultaneous introduction of hosts and parasites with the latter establishing themselves in native hosts, is a phenomenon of ecological concern. Rattus rattus, a notorious invasive species, has driven the extinction and displacement of numerous avian and mammalian species and serves as a key vector for diseases affecting both humans and wildlife. Among the parasites hosted by R. rattus are fleas, which exhibit obligate parasitic behaviour, a generalist nature and high prevalence, increasing the likelihood of flea invasion. Simultaneously, invasive species can serve as hosts for native parasites, leading to potential amplification or dilution of parasite populations in the environment. In Chile, R. rattus has been present since the 17th century because of the arrival of the Spanish colonizers through the ports and has spread throughout urban, rural and wild Chilean territories. This study aims to evaluate whether co-invasion of native fleas of invasive rats occurs on native rodents in Chile and to determine whether black rats have acquired flea native to Chile during their invasion. For this, we captured 1132 rodents from 26 localities (20° S-53° S). Rattus rattus was found coexisting with 11 native rodent species and two species of introduced rodents. Among the native rodents, Abrothrix olivacea and Oligoryzomys longicaudatus exhibited more extensive sympatry with R. rattus. We identified 14 flea species associated with R. rattus, of which only three were native to rats: Xenopsylla cheopis, Leptopsylla segnis and Nosopsyllus fasciatus. These three species presented a higher parasite load in black rats compared to native fleas. Leptopsylla segnis and N. fasciatus were also found associated with native rodent species that cohabit with R. rattus. The remaining species associated with R. rattus were fleas of native rodents, although they were less abundant compared to those associated with native rodents, except for Neotyphloceras pardinasi and Sphinctopsylla ares. Although there has been evidence of flea transmission from rats to native species, the prevalence and abundance were relatively low. Therefore, it cannot be definitively concluded that these fleas have established themselves in native rodent populations, and hence, they cannot be classified as invasive fleas. This study underscores R. rattus' adaptability to diverse environmental and geographical conditions in Chile, including its capacity to acquire fleas from native rodents. This aspect has critical implications for public health, potentially facilitating the spread of pathogens across various habitats where these rats are found.

Parásitos en un venado de cola blanca silvestre en Cajamarca, Perú

En el presente estudio se informa sobre los parásitos encontrados en un venado de cola blanca, Odocoileus virginianus peruvianus, capturado en el bosque seco del distrito de Paccha, provincia de Chota, departamento de Cajamarca. El Servicio Nacional Forestal y de Fauna Silvestre recuperó los parásitos de un espécimen macho adulto y las remitió al Centro de Investigación en Medicina Tropical de la Universidad Nacional de Cajamarca para la identificación taxonómica de helmintos y artrópodos, y análisis coproparasitológico. Se identificaron dos metacéstodos correspondientes a Cysticercus tenuicollis. En los análisis coproparasitológicos cualitativos se hallaron huevos de Nematodirus spp. en una carga de 10 por gramo de heces (h.p.g.) y 40 h.p.g. tipo Strongílidos que no pudieron diferenciarse por la baja carga en el coprocultivo. No se detectaron huevos de trematodos en la sedimentación. De ectoparásitos, se identificaron ocho garrapatas duras Rhipicephalus (Boophilus) microplus y cinco piojos chupadores Solenopotes binipilosus. Varios de los ejemplares fueron depositados en el Museo de Historia Natural de la Universidad Nacional Mayor de San Marcos, Lima. Los hallazgos representan el primer reporte formal de la garrapata común del ganado en esta subespecie de cérvido. Además, se registra por primera vez la presencia del piojo Solenopotes binipilosus en territorio peruano.

In the present study, findings regarding parasites discovered in a white-tailed deer, Odocoileus virginianus peruvianus, captured in the dry forest of the Paccha district, Chota province, Cajamarca department, are reported. The Servicio Nacional Forestal y de Fauna Silvestre recovered parasites from an adult male specimen and forwarded them to the Tropical Medicine Research Center at the Universidad Nacional de Cajamarca for taxonomic identification of helminths and arthropods, as well as coproparasitological analysis. Two metacestodes corresponding to Cysticercus tenuicollis were identified. Qualitative coproparasitological analyses revealed Nematodirus spp. eggs at a concentration of 10 eggs per gram of feces (EPG) and 40 EPG of Strongylid type that could not be differentiated due to low counts in the coproculture. No trematode eggs were detected in the sedimentation. Among ectoparasites, eight hard ticks Rhipicephalus (Boophilus) microplus and five sucking lice Solenopotes binipilosus were identified. Several specimens were deposited in the Museo de Historia Natural de la Universidad Nacional Mayor de San Marcos, Lima. These findings represent the first formal report of the common cattle tick in this subspecies of cervid. Additionally, the presence of the Solenopotes binipilosus louse in Peruvian territory is reported for the first time.

Specificity of fleas associated with opossums in a landscape gradient in the Paranaense Rainforest Ecoregion.

The degree of host specificity of fleas varies from highly specific (monoxenous) to opportunistic (polyxenous). Specific parasite-host associations can be observed among some flea families and tribes and mammalian orders, such as fleas of the tribe Tritopsyllini (Ctenophthalmidae, Doratopsyllinae) and opossums (Didelphimorphia). Specimens of the family Didelphidae are common hosts of fleas of the genus Adoratopsylla (Ewing, 1925). In northern Argentina, Adoratopsylla (Adoratopsylla) antiquorum antiquorum (Rothschild, 1904) and Adoratopsylla (Tritopsylla) intermedia intermedia (Wagner, 1901) were recorded preferentially parasitizing opossums. In order to study parasite/host relationships, fleas were collected from opossums captured in different environments in the Paranaense Rainforest ecoregion, northern Misiones province between 2016 and 2018. A total of 287 fleas were collected from 110 opossums. The fleas were identified as Pulicidae: Ctenocephalides felis felis (Bouché, 1835); Rhopalopsyllidae: Polygenis (Polygenis) rimatus (Jordan, 1932), Polygenis (Polygenis) roberti roberti (Rothschild, 1905); Ctenophthalmidae: A. (T.) i. intermedia, A. (A.) a. antiquorum, Adoratopsylla (Adoratopsylla) antiquorum ronnai (Guimarães, 1954). We report for the first time in Argentina a male specimen of A. (A.) a. ronnai collected on Didelphis albiventris (Lund, 1840) (Didelphidae), and male and female specimens of P. (P.) r. roberti collected on Didelphis aurita (Wied-Neuwied, 1826), and we describe the expansion of the geographic and host distribution of fleas to the Paranaense Rainforest ecoregion. Our records reinforce the specific association between Adoratopsylla and Polygenis fleas and didelphid opossums, mentioned in the literature for the Atlantic Forest ecoregion in Brazil. Furthermore, we observed that flea communities in opossums change in a landscape gradient, with invasive cat fleas and euryxenous fleas common in anthropized areas, and endemic fleas common in natural areas. Our results underline the importance for public health and veterinary medicine the analysis of flea circulation between wild and urban environments due to the risk of pathogen transmission.

Ecological factors shaping the ectoparasite community assembly of the Azara's Grass Mouse, Akodon azarae (Rodentia: Cricetidae).

Parasites are integral members of the global biodiversity. They are useful indicators of environmental stress, food web structure and diversity. Ectoparasites have the potential to transmit vector-borne diseases of public health and veterinary importance and to play an important role in the regulation and evolution of host populations. The interlinkages between hosts, parasites and the environment are complex and challenging to study, leading to controversial results. Most previous studies have been focused on one or two parasite groups, while hosts are often co-infected by different taxa. The present study aims to assess the influence of environmental and host traits on the entire ectoparasite community composition of the rodent Akodon azarae. A total of 278 rodents were examined and mites (Mesostigmata), lice (Phthiraptera), ticks (Ixodida) and fleas (Siphonaptera) were determined. A multi-correspondence analysis was performed in order to analyze interactions within the ectoparasite community and the influence of environmental and host variables on this assembly. We found that environmental variables have a stronger influence on the composition of the ectoparasite community of A. azarae than the host variables analyzed. Minimum temperature was the most influential variable among the studied. In addition, we found evidence of agonistic and antagonistic interactions between ticks and mites, lice and fleas. The present study supports the hypothesis that minimum temperature plays a major role in the dynamics that shape the ectoparasite community of A. azarae, probably through both direct and indirect processes. This finding becomes particularly relevant in a climate change scenario.

An integrative approach to explore species limits in Laelaps mazzai Fonseca, 1939 (Mesostigmata, Laelapidae), a South American widespread mite parasitizing the cricetid Calomys Waterhouse, 1837.

Laelaps mazzai Fonseca, 1939 (Mesostigmata, Laelapidae) parasitizes several species of the widespread South American rodent genus Calomys Waterhouse, 1837. Morphological variation has been noticed within this laelapid but has yet to be analyzed. Since several other species of laelapids that initially were considered generalists have resulted in host-specific species, after further analyses, herein we explored, through morphology and genetics, the variation of this parasite across six species of Calomys, trying to establish if it constitutes a polymorphic species or a complex of cryptic host specific-species. An integrative approach was applied, including principal component and discriminant analyses of females and males and DNA sequences (nuclear region ITS and the COI gene). The obtained results indicate that female mites tend to differentiate only the sizes of their dorsal shield among host species but with extensive overlapping. At the same time the males lack metrical differentiation, and the genetic evidence failed to resolve specific-species clades. We conclude that L. mazzai is a single widespread mite with little genetic and phenotypic differentiation.

The species composition of local flea assemblages at a small scale in two South American regions is predominantly driven by niche-based mechanisms.

We applied a step-down factor analysis (SDFA) and multi-site generalised dissimilarity modelling (MS-GDM) to local flea communities harboured by small mammals (i.e., collected at small sampling sites over a short time period) in two South American regions (Patagonia and the Northwestern Argentina) with the aim of understanding whether these communities were assembled via niche-based or dispersal-based processes. The SDFA allows us to determine whether clusters of flea assemblages across different types of climates, vegetation and soils can be distinguished (suggesting niche-based assembly). MS-GDM allows us to determine whether a substantial proportion of the variation in flea species turnover is explained by specific climate-associated, vegetation-associated and soil-associated variables (indicating niche-based assembly) or host turnover (indicating dispersal-based assembly). Mapping of assemblages on climate, vegetation and soil maps, according to their loadings on axis 1 or axis 2 of the SDFA, did not provide clear-cut results. Clusters of similar loadings could be recognized within some, but not other, climate, vegetation and soil types. However, MS-GDM demonstrated that the effect of environmental variables (especially air temperature) on flea compositional turnover was much stronger than that of host turnover, indicating the predominance of niche-based processes in local community assembly. A comparison of our results with those on the mechanisms that drive species assembly in regional communities allows us to conclude that local and regional communities result from the joint action of niche-based and dispersal-based processes, with the former more important at a smaller spatial scale and the latter at a larger spatial scale.

Factors associated with prevalence and intensity of the northern fowl mite (Ornithonyssus sylviarum) in commercial poultry farms of Argentina.

The haematophagous mite Ornithonyssus sylviarum may cause important economic losses in commercial poultry farms whilst also potentially affecting the health of farm workers. The dynamics of this ectoparasite has been linked to several factors, including wild birds, fomites, farm workers, management of hen houses, and host traits. Along two consecutive years, we carried out systematic sampling at three laying hen farms located in Santa Fe province, Argentina, with the aim of identifying factors that may influence O. sylviarum prevalence and intensity. We found that the density of feathers around the hen vent area and the presence of Menoponidae lice were negatively associated with mite abundance. We also found that the density of hens in the cages was negatively associated with mite prevalence, suggesting a possible dilution effect, whereas prior reports found a positive association with hen density. In addition, summer was the season with minimum mite prevalences and intensities, contrary to previous studies in northern farms where warm weather appeared to prompt an increase in mite populations. Another factor associated with mite intensity was age, but this effect varied depending on the season, which hints that the association between hen's age and mites is complex. Basic epidemiological knowledge on O. sylviarum in poultry farms from South America may aid in a more efficient and integrative approach to its control.

Effects of host factors on the dynamics of fleas (Siphonaptera) in Sigmodontinae rodents (Cricetidae) from El Espinal Ecoregion, Argentina.

We investigated the patterns of flea infestation in wild populations of eight Sigmodontinae rodent species: Akodon azarae, Calomys callidus, Calomys venustus, Holochilus chacarius, Necromys lasiurus, Oligoryzomys flavescens, Oligoryzomys nigripes and Oxymycterus rufus. Rodents were captured in systematic trapping sessions carried out along 2 years at two localities from El Espinal Ecoregion, Argentina. Mean flea intensity, occurrence (presence/absence) of flea infestation, richness and diversity were compared for different ages, body condition, sex and rodent tribes (Akodontini, Oryzomyini and Phyllotini). A total of 376 fleas of the following species and subspecies were collected: Craneopsylla minerva wolffhuegeli, Polygenis (Neopolygenis) pradoi, Polygenis (Polygenis) axius axius, and Polygenis (Polygenis) byturus. The most important factor driving flea infestation was the rodent tribe, with Phyllotini showing the highest values of occurrence, abundance and species richness. Only C. m. wolffhuegeli was affected by the sex of the host. Age and body condition of the hosts did not affect flea infestation. Our results contribute to knowledge of the ecology of fleas on rodent hosts in El Espinal Ecoregion. The relevance of host taxonomy as driver of flea dynamics highlight the importance of considering host community structures at the time of studying the ecology of parasites.

Validation of the names of four species of laelapid mites (Mesostigmata: Laelapidae) parasitic on sigmodontine rodents (Rodentia: Cricetidae).

Savchenko Lareschi (2019) and Lareschi (2020) described four new species of mites in the family Laelapidae. However, the papers were published in electronic form only and were not registered in ZooBank. They do not satisfy Article 8.5.3 of the International Code of Zoological Nomenclature (ICZN 2012), so the new names are not available from those papers. Therefore, the aim of the present note is to validate the names Laelaps schatzi, Androlaelaps azarae, Androlaelaps montensis and Androlaelaps cursor. Type specimens of the four new species are deposited in the Coleccin de Entomologa, Museo de la Plata, Argentina.

Three new species of Laelapidae mites (Mesostigmata) parasitic of species of Akodon (Rodentia: Cricetidae: Sigmodontinae) on the basis of female, male and deutonymph specimens.

Three new species of Androlaelaps (Mesostigmata: Laelapidae) are described on the basis of the female and male specimens, and deutonymph for two of them. Each of the new species parasitizes a different species of Akodon (Rodentia: Cricetidae: Sigmodontinae). Diagnostic characteristics support that the three new species are included in the Androlaelaps rotundus species group, and may be differentiated between them because of the length of proximal seta in coxa I; distances j5-j5, j6-j6 and z5-z5 setae in males and females; and length of st3, and st1 setae in females. Out of the seven species included in A. rotundus species-group, only the males of three of them are known, while immature stages are unknown. The new information herein provided contributes to a better knowledge of the laelapid mites and is essential to further investigate the epidemiological role of these mites as vectors of pathogens.

Molecular detection of Rickettsia in fleas from micromammals in Chile.

BACKGROUND: Rickettsial diseases are considered important in public health due to their dispersal capacity determined by the particular characteristics of their reservoirs and/or vectors. Among the latter, fleas play an important role, since the vast majority of species parasitize wild and invasive rodents, so their detection is relevant to be able to monitor potential emerging diseases. The aim of this study was to detect, characterize, and compare Rickettsia spp. from the fleas of micromammals in areas with different human population densities in Chile. METHODS: The presence of Rickettsia spp. was evaluated by standard polymerase chain reaction (PCR) and sequencing in 1315 fleas collected from 1512 micromammals in 29 locations, with different human population densities in Chile. A generalized linear model (GLM) was used to identify the variables that may explain Rickettsia prevalence in fleas. RESULTS: DNA of Rickettsia spp. was identified in 13.2% (174 of 1315) of fleas tested. Fifteen flea species were found to be Rickettsia-positive. The prevalence of Rickettsia spp. was higher in winter, semi-arid region and natural areas, and the infection levels in fleas varied between species of flea. The prevalence of Rickettsia among flea species ranged between 0-35.1%. Areas of lower human density showed the highest prevalence of Rickettsia. The phylogenetic tree showed two well-differentiated clades with Rickettsia bellii positioned as basal in one clade. The second clade was subdivided into two subclades of species related to Rickettsia of the spotted fever group. CONCLUSIONS: To our knowledge, this is the first report of the occurrence and molecular characterization of Rickettsia spp. in 15 flea species of micromammals in Chile. In this study, fleas were detected carrying Rickettsia DNA with zoonotic potential, mainly in villages and natural areas of Chile. Considering that there are differences in the prevalence of Rickettsia in fleas associated with different factors, more investigations are needed to further understand the ecology of Rickettsia in fleas and their implications for human health.

Molecular detection and identification of Rickettsia felis in Polygenis (Siphonaptera, Rhopalopsyllidae, Rhopalopsyllinae) associated with cricetid rodents in a rural area from central Argentina.

The aim of this study was to detect and identify the presence of Rickettsia in fleas associated with cricetid rodents from northeastern Buenos Aires Province, Argentina. Sixteen fleas belonging to three species of Polygenis were collected from 56 cricetid rodents and analyzed for the presence of Rickettsia performing the conventional polymerase chain reaction (PCR) technique. Only one specimen of Polygenis (Polygenis) axius axius collected from Oxymycterus rufus was positive for Rickettsia felis using the gltA gene, and to ompA gene. This is the first report of R. felis in a Rhopalopsyllidae flea from Argentina, and the first detection of this bacterium in P. (P.) a. axius. Since both, O. rufus and P. (P.) a. axius, are common in areas close to humans, and enzootic cycle of R. felis is not fully understood, the results herein obtained might be of epidemiological importance. Further studies are needed in order to analyze the capacity of the species of Polygenis to transmit R. felis.

Mesostigmatid mites (Acari: Mesostigmata) at the domestic-wildlife interface: Poultry and passerine birds of central Argentina.

Wild birds may be considered a possible source of parasitic mesostigmatid mites for poultry, but only few studies explored this hypothesis. In addition, there is very little information about the parasitic mites present in commercial poultry systems from southern South America. To contribute with data on parasitic mesostigmatid mites at the domestic-wildlife interface, we conducted a study in which samples were systematically collected from laying hens and wild birds (adults and nestlings), for two years at three commercial laying hen farms. The occurrence of mesostigmatid mites were compared among hosts. A proportion of the collected mites were morphologically identified to the species level, finding that host preference varied greatly depending on mite species: laying hens were only parasitized by Ornithonyssus sylviarum, wild bird nestlings were mostly parasitized by Ornithonyssus bursa, and in small proportion, by O. sylviarum, while adult passerines were parasitized by both Ornithonyssus species, and sporadically by Pellonyssus cf. reedi and Dermanyssus cf. triscutatus. In laying hens, there was intra- and inter-annual variability in mite occurrence, but no consistent seasonal pattern, whereas in adult wild birds, mites showed the highest prevalence in spring and the lowest in summer. Not coinciding with this general pattern, the occurrence of O. bursa matched the reproductive activity of wild birds. A phylogenetic analysis based on a fragment of the 16S rRNA gene was carried out for a subsample of the mites collected, showing that the O. sylviarum mites present on adult wild birds and laying hens had the same haplotype (100% identity). Additionally, mites obtained from wild birds morphologically identified as O. bursa presented two distinctive haplotypes (89.8% identity), one phylogenetically related to O. sylviarum and the other to O. monteiroi. These findings show that in central Argentina commercial laying hens are parasitized mainly by O. sylviarum while wild birds are also hosts to other mite species. Adult wild passerines, especially house sparrows, may be a source of O. sylviarum for commercial poultry.

Morphometric variation of Androlaelaps fahrenholzi (Mesostigmata: Laelapidae) associated with three Sigmodontinae (Rodentia: Cricetidae) from the north of Chile.

Androlaelaps fahrenholzi is a mite with a large distribution and associated with a wide range of hosts. To assess morphometric variation of A. fahrenholzi associated with different host species (Phyllotis xanthopygus and Akodon albiventer, both from Putre, Chile) and localities (Las Chinchillas National Reserve, Fray Jorge National Park, and Llanos de Challe National Park, all in Chile and all from the host Phyllotis darwini), 41 morphological characters of each specimen were measured, and principal component analysis and discriminant analysis were used. Both analyses showed two groups separated for species of rodents. Mites associated with P. xanthopygus are smaller than those of A. albiventer. The analysis by location indicates two groups: group 1 comprises all mites collected from Fray Jorge National Park and Las Chinchillas National Reserve, and group 2 comprises only mites from Llanos de Challe National Park. These results indicate that A. fahrenholzi population can vary between hosts and geographical areas. Molecular analysis would be necessary to validate these results and determine whether they are subspecies or different species.

Molecular detection and identification of Bartonella in the cat flea Ctenocephalides felis felis collected from companion animals in a border area in northeastern Argentina.

Molecular methods were used to detect and identify Bartonella species in the cat fleas Ctenocephalides felis felis from Puerto Iguazú, a border area in northeastern Argentina. The fleas were collected from 12 household animals, 9 dogs (Canis lupus familiaris) and 3 cats (Felis silvestris catus) during July 2016. Out of 15C. f. felis analyzed for PCR, only one flea collected from a cat was positive (6.66%) in screened for Bartonella spp. based on the gltA gene. Bartonella clarridgeiae was identified in the genetic analyses, this specimen clustered monophyletically with others B. clarridgeiae isolated from different geographical origins (1.0 PP), even, all shared the same haplotype. The results obtained provide evidence of the presence of B. clarridgeiae in cat fleas from Argentina suggesting the probable presence of related flea-borne diseases in the region and the role of cat fleas in the transmission of Bartonella among mammals including humans.

Fleas of black rats (Rattus rattus) as reservoir host of Bartonella spp. in Chile.

BACKGROUND: Rattus rattus is a widely distributed, invasive species that presents an important role in disease transmission, either directly or through vector arthropods such as fleas. These black rats can transmit a wide variety of pathogens, including bacteria of the genus Bartonella, which can cause diseases in humans and animals. In Chile, no data are available identifying fleas from synanthropic rodents as Bartonella vectors. The aim of this study was to investigate the prevalence of Bartonella spp. in the fleas of R. rattus in areas with different climate conditions and featuring different human population densities. METHODS: In all, 174 fleas collected from 261 R. rattus captured from 30 localities with different human densities (cities, villages, and wild areas) across five hydrographic zones of Chile (hyper-arid, arid, semi-arid, sub-humid, and hyper-humid) were examined. Bartonella spp. presence was determined through polymerase chain reaction, using gltA and rpoB genes, which were concatenated to perform a similarity analysis with BLAST and phylogenetic analysis. RESULTS: Overall, 15 fleas species were identified; Bartonella gltA and rpoB fragments were detected in 21.2% (37/174) and 19.5% (34/174) of fleas, respectively. A total of 10 of the 15 fleas species found were positive for Bartonella DNA. Leptopsylla segnis was the most commonly collected flea species (n = 55), and it also presented a high prevalence of Bartonella DNA (P% = 34.5%). The highest numbers of fleas of this species were collected in villages of the arid zone. There were no seasonal differences in the prevalence of Bartonella DNA. The presence of Bartonella DNA in fleas was recorded in all hydrographic areas, and the arid zone presented the highest prevalence of this species. Regarding areas with different human densities, the highest prevalence was noted in the villages (34.8% gltA and 31.8% rpoB), followed by cities (14.8% gltA and 11.1% rpoB) and wild areas (7.4% gltA and 14.8% rpoB). The BLAST analysis showed a high similitude (>96%) with four uncharacterized Bartonella genotypes and with two species with zoonotic potential: B. mastomydis and B. tribocorum. The phylogenetic analysis showed a close relationship with B. elizabethae and B. tribocorum. This is the first study to provide evidence of the presence of Bartonella in fleas of R. rattus in Chile, indicating that the villages and arid zone correspond to areas with higher infection risk.

Fleas associated with sigmodontine rodents and marsupials from the Paranaense Forest in Northeastern Argentina.

Fleas from the Paranaense Forest in northeastern Argentina are studied. Herein we provided a list of specimens identified, which includes host species and geographical distribution for each taxa, as well as some comments on the morphology, distribution and epidemiological importance when available. The following eight species and subspecies of fleas belonging to four families were identified: Ctenocephalides felis felis (Pulicidae), Craneopsylla minerva minerva (Stephanocircidae), Polygenis (Polygenis) platensis, Polygenis (Polygenis) roberti beebei, Polygenis (Neopolygenis) pradoi, Polygenis (Neopolygenis) pygaerus (Rhopalopsyllidae), Adoratopsylla (Adoratopsylla) antiquorum antiquorum, and Adoratopsylla (Tritopsylla) intermedia intermedia (Ctenophthalmidae). The results obtained increase to eleven the known diversity of fleas in the Argentinean Paranaense Forest area. Seven new flea-host associations are reported for the first time. In addition, all the species and subspecies are mentioned for the first time for the province of Misiones. Besides, the results contribute to the knowledge of mammal ectoparasites and to their biodiversity of the Province, necessary to a better understanding of their role as parasites themselves and vectors of zoonotic importance.

Predicting species richness of ectoparasites of wild rodents from the Río de la Plata coastal wetlands, Argentina.

The richness of ectoparasite species associated with Sigmodontinae rodents (Cricetidae) from different sites located in the coastal wetlands of the Río de la Plata in Argentina was predicted by a model with three components: (1) habitat type, considered analogous to rodent species; (2) average ectoparasite species richness on each rodent species, and (3) average number of rodent species parasitized by each ectoparasite species. The model, based on rodent information (number of species and total number of captured rodents) and the environmental gradient, has a reasonably good fit for the observed data as well as independent data from different localities. The model is predictive and robust, and it could be a useful tool for epidemiological and biodiversity management strategies. Furthermore, the model could be adapted to other habitats if a suitable estimate of an environmental gradient is found, and it could be also possible to adapt it to other host taxa.

Prevalence and intensity of fleas parasitizing an isolated population of screaming hairy armadillo in Buenos Aires province, Argentina: host-related factors and temporal dynamics.

Fleas (Siphonaptera) of an isolated population of Chaetophractus vellerosus (Mammalia: Xenarthra) from Magdalena (Buenos Aires province) were studied, and their presence was associated with host-related factors (age, sex, weight, size, and physical condition) and temporal dynamics (seasonality and year). Three species of fleas were identified: Polygenis (Polygenis) platensis (Rhopalopsyllidae), Tunga penetrans (Tungidae), and Pulex irritans (Pulicidae). Prevalences were significant for year, season, and physical condition. Intensities were significantly different for year, physical condition, and weight. The intensities of fleas were higher in 2009 than in other years, probably because of lower rainfall than the annual average leading to extremely dry climatic conditions in 2008. Intensities decreased in individuals with major body weight and increased in individuals with poor physical condition. In this study, the dynamics of the flea community associated with an armadillo population is analyzed for the first time taking into account host-related factors and temporal dynamics, and also how these factors influence the community.

Borrelia burgdorferi sensu lato in Ixodes cf. neuquenensis and Ixodes sigelos ticks from the Patagonian region of Argentina.

This study was conducted to detect Borrelia burgdorferi sensu lato infection in ixodid ticks from the Patagonia region in the south of Argentina. Therefore, ticks were collected on rodents in the provinces of Chubut, Río Negro and Santa Cruz. These ticks were identified as nymphs of Ixodes cf. neuquenensis and Ixodes sigelos. The B. burgdorferi s.l. infection was tested by a battery of PCR methods targeting the gene flagellin (fla) and the rrfA-rrlB intergenic spacer region (IGS). Three pools of I. sigelos nymphs from Chubut and Santa Cruz provinces as well as one pool of I. cf. neuquenensis nymphs from Río Negro province were tested positive in the fla-PCR. The samples of I. sigelos were also positive for the IGS-PCR. Phylogenetically, the haplotypes found in the positive ticks belong to the B. burgdorferi s.l. complex, and they were closely related to Borrelia chilensis, a genospecies isolated from Ixodes stilesi in Chile. The pathogenic relevance of the Borrelia genospecies detected in both I. neuquenensis and I. sigelos is unknown.