Wild rodent fleas carrying Bartonella and Rickettsia in an area endemic for vector-borne diseases from Argentina.

Vector-borne diseases account for nearly 20% of all globally recognised infectious diseases. Within the spectrum of flea-borne pathogens, Bartonella and Rickettsia bacteria are prominent, contributing to the emergence and resurgence of diseases on a global scale. This study investigates the presence of species of Bartonella and Rickettsia harboured by fleas collected from wild rodents in northwestern Argentina (NWA). A total of 28 fleas from three genera and seven species were assessed. DNA of Bartonella and Rickettsia spp. was found in 12 fleas (42.8%). Phylogenetic analysis of concatenated sequences of gltA and rpoB genes showed the presence of Bartonella quintana in eight fleas of two species, Craneopsylla minerva minerva and Polygenis acodontis. Phylogenetic analysis of concatenated sequences of gltA, ompA and ompB genes identified Rickettsia felis in ten fleas of five species, C. m. minerva, P. acodontis, Polygenis bohlsi bohlsi, Polygenis byturus and Tiamastus palpalis. These bacterial species mark the first report in all flea species studied. This study represents the first survey of flea-borne bacteria for NWA. The results provide information to address strategies for the control and prevention of bartonellosis and rickettsiosis that could have an impact on public health in one of the geographical areas of Argentina with the highest incidence of infections transmitted to humans by ectoparasites.

Congruence between co-occurrence and trait-based networks is scale-dependent: a case study with flea parasites of small mammalian hosts.

We applied a novel framework based on network theory and a concept of modularity that estimates congruence between trait-based ( = functional) co-occurrence networks, thus allowing the inference of co-occurrence patterns and the determination of the predominant mechanism of community assembly. The aim was to investigate the relationships between species co-occurrence and trait similarity in flea communities at various scales (compound communities: across regions within a biogeographic realm or across sampling sites within a geographic region; component communities: across sampling sites within a geographic region; and infracommunities: within a sampling site). We found that compound communities within biogeographic realms were assembled via environmental or host-associated filtering. In contrast, functional and spatial/host-associated co-occurrence networks, at the scale of regional compound communities, mostly indicated either stochastic processes or the lack of dominance of any deterministic process. Analyses of congruence between functional and either spatial (for component communities) or host-associated (for infracommunities) co-occurrence networks demonstrated that assembly rules in these communities varied among host species. In component communities, stochastic processes prevailed, whereas environmental filtering was indicated in 4 and limiting similarity/competition in 9 of 31 communities. Limiting similarity/competition processes dominated in infracommunities, followed by stochastic mechanisms. We conclude that assembly processes in parasite communities are scale-dependent, with different mechanisms acting at different scales.

Relationships between functional alpha and beta diversities of flea parasites and their small mammalian hosts.

We studied the relationships between functional alpha and beta diversities of fleas and their small mammalian hosts in 4 biogeographic realms (the Afrotropics, the Nearctic, the Neotropics and the Palearctic), considering 3 components of alpha diversity (functional richness, divergence and regularity). We asked whether (a) flea alpha and beta diversities are driven by host alpha and beta diversities; (b) the variation in the off-host environment affects variation in flea alpha and beta diversities; and (c) the pattern of the relationship between flea and host alpha or beta diversities differs between geographic realms. We analysed alpha diversity using modified phylogenetic generalized least squares and beta diversity using modified phylogenetic generalized dissimilarity modelling. In all realms, flea functional richness and regularity increased with an increase in host functional richness and regularity, respectively, whereas flea functional divergence correlated positively with host functional divergence in the Nearctic only. Environmental effects on the components of flea alpha diversity were found only in the Holarctic realms. Host functional beta diversity was invariantly the best predictor of flea functional beta diversity in all realms, whereas the effects of environmental variables on flea functional beta diversity were much weaker and differed between realms. We conclude that flea functional diversity is mostly driven by host functional diversity, whereas the environmental effects on flea functional diversity vary (a) geographically and (b) between components of functional alpha diversity.

Environment and traits affect parasite and host species positions but not roles in flea-mammal networks.

We studied spatial variation in the effects of environment and network size on species positions and roles in multiple flea-mammal networks from four biogeographic realms. We asked whether species positions (measured as species strength [SS], the degree of interaction specialization [d'], and the eigenvector centrality [C]) or the roles of fleas and their hosts in the interaction networks: (a) are repeatable/conserved within a flea or a host species; (b) vary in dependence on environmental variables and/or network size; and (c) the effects of environment and network size on species positions or roles in the networks depend on species traits. The repeatability analysis of species position indices for 441 flea and 429 host species, occurring in at least two networks, demonstrated that the repeatability of SS, d', and C within a species was significant, although not especially high, suggesting that the indices' values were affected by local factors. The majority of flea and host species in the majority of networks demonstrated a peripheral role. A value of at least one index of species position was significantly affected by environmental variables or network size in 41 and 36, respectively, of the 52 flea and 52 host species that occurred in multiple networks. In both fleas and hosts, the occurrence of the significant effect of environment or network size on at least one index of species position, but not on a species' role in a network, was associated with some species traits.

New record of Alectopsylla unisetosa (Siphonaptera: Ischnopsyllidae) from Patagonia.

Alectopsylla unisetosa (Ischnopsyllidae) from Santa Cruz province represents the second report of the species after 45 years. This new distributional record extends this species distribution 1350 km further south than previously documented. Moreover, Alectopsylla unisetosa infesting Myotis chiloensis constitutes a new flea-host association. This finding provides new insights into the biogeography and host associations within the family Ischnopsyllidae.

Fleas of mammals and patterns of distributional congruence in northwestern Argentina: A preliminary biogeographic analysis.

In few groups of parasites have the patterns of distribution been studied using quantitative methods, even though, the study of these organisms indirectly provides information on the biogeographic history of their hosts, and in turn, the history of the hosts allows elucidation of speciation events of the parasites. Our objective was to quantitatively identify distributional congruence patterns of native fleas in northwestern Argentina. We analyzed 159 georeferenced distributional records of 47 species and six subspecies of fleas in northwestern Argentina using NDM/VNDM software. We found eight consensus areas, defined by 17 species and two subspecies, included in six patterns of distributional congruence (PDCs) with endemic and non-endemic fleas. The PDCs with the greatest values of endemicity (E) were mainly associated with Monte and Yungas Forests areas. All patterns indicated strong tendency of the Yungas Forests as a possible endemism area. Our results indicate that distributional congruence centers are generally located in Yungas Forests areas and highlight the importance of these areas in conservation and historical biology. This new information will allow delimitation of areas in the region at a more detailed resolution in the future.

Description of two new species of Ectinorus (Ectinorus) (Siphonaptera, Rhopalopsyllidae) from Argentina, including a morphometric approach.

Two new species of fleas of genus Ectinorus (Siphonaptera: Rhopalopsyllidae) are described from sigmodontine rodents (Rodentia: Cricetidae) collected during a survey of small mammals in northwestern Argentina.The new species belong to the subgenus Ectinorus and can be distinguished from all other species of the subgenus by the characteristics of the modified abdominal segments and by the genitalia. Moreover, the male of Ectinorus (Ectinorus) disjugis is described for the first time and the finding of this flea parasitizing the rodent Akodon spegazzinii, constitutes a new flea-host association. A phylogenetic analysis of the genus Ectinorus, using traditional morphological characters and morphogeometric data, is presented to support the erection of the new species of Ectinorus. An identification key for all species of Ectinorus is also provided. Our study increases to 38 the total number of species of the subgenus Ectinorus, and to 20 the number for Argentina. Phylogenetic analyses reveal that Ectinorus is monophyletic but the subgenera are not. This study offers a new interpretation of morphological diversity within the genus as well as an evaluation of hypotheses about their relationships.

Fleas of the genus Tetrapsyllus (Siphonaptera:Rhopalopsyllidae) associated with rodents from Northwestern Argentina.

A new species of flea (Siphonaptera: Rhopalopsyllidae) is described from sigmodontine rodents collected during a survey of small mammals in northwestern Argentina. The new species belongs to the subgenus Tetrapsyllus and can be distinguished from all species of the subgenus by characteristics of the modified abdominal segments and genitalia. A phylogenetic analysis of the genus Tetrapsyllus using morphological characters is presented and the analysis supports the erection of this new Tetrapsyllus species in the subgenus Tetrapsyllus. The unique occurrence of a sinus in the caudal margin of the sixth sternite of females that is present only in the subgenus Tetrapsyllus (also unique across the Order Siphonaptera) is provided with a discussion of how this adaptation is mirrored in the parallel development of a spur on the sclerotized inner tube of males. Additional host and locality data are recorded for Tetrapsyllus (P.) bleptus. A key to the genus Tetrapsyllus is provided. The increased diversity of flea fauna bordering a known plague endemic area in northwestern Argentina may prove useful in implementing sustainable control measures in the future.

A New Flea Species of the Genus Cleopsylla (Siphonaptera: Stephanocircidae) from Northwestern Argentina.

A new species of flea of the genus Cleopsylla Rothschild, 1914 (Siphonaptera: Stephanocircidae) is described from sigmodontine rodents from northwestern Argentina. In Argentina, the genus was cited for the first time in 2008, but the species was erroneously identified. An identification key to species of Cleopsylla is presented.

A new flea of the genus Ctenidiosomus (Siphonaptera, Pygiopsyllidae) from Salta Province, Argentina.

A new species of flea of the genus Ctenidiosomus Jordan, 1931 (Siphonaptera: Pygiopsyllidae) is described from Phyllotisosilae J. A. Allen, 1901, from Salta Province, Argentina. This is the first time that Ctenidiosomus has been recorded in Argentina. A key to species of males of Ctenidiosomus is presented.

ResumenUna nueva especie de pulga del género Ctenidiosomus Jordan, 1931 (Siphonaptera: Pygiopsyllidae) es descripta de Phyllotisosilae J. A. Allen, 1901, de la provincia de Salta, Argentina. Cabe mencionar que es la primera vez que el género Ctenidiosomus ha sido registrado en Argentina. Se ofrece una clave para los machos de las especies de Ctenidiosomus.

Redescription of Neotyphloceras crassispina hemisus Jordan (Siphonaptera: Ctenophthalmidae: Neotyphloceratini).

Neotyphloceras crassispina hemisus Jordan is redescribed from male and female specimens collected at the type locality (Otro Cerro, Catamarca Province, Argentina) and nearby localities. New diagnostic morphological characters for both sexes are provided, which include the shape of the upper lobe of the fixed process of clasper, the crochet of the aedeagus and the shape and chaetotaxy of the distal arm of sternum IX for males, and the contour of the distal margin of sternum VII for females.