Diversity, distribution and parasitism rates of fleas (Insecta: Siphonaptera) on sigmodontine rodents (Cricetidae) from Argentinian Patagonia

2018 ◽  
Vol 109 (1) ◽  
pp. 72-83 ◽  
Author(s):  
J. Sanchez ◽  
M. Lareschi
Keyword(s):  
Host Species ◽  
Arid Regions ◽  
Epidemiological Studies ◽  
Surveillance Systems ◽  
Parasitism Rate ◽  
Host Environment ◽  
Ecological Aspects ◽  
Parasitism Rates ◽  
Survival And Development ◽  
Causative Agents

AbstractFleas have great medical relevance as vectors of the causative agents of several diseases in animals and humans and rodents are the principal reservoirs for these pathogens. Argentinian Patagonia has the highest diversity of rodent fleas in South America. However, parasitism rates of rodents by fleas, the factors that influence them and the ecological aspects that modulate geographical distributions of flea–host association remain unknown for this region. This is the first study to record the diversity, prevalence, abundance, geographical distributions and host ranges of fleas in Argentinian Patagonia. It also compares parasitism rates among Patagonian ecoregions and host species. We captured 438 rodents belonging to 13 species, which harboured 624 fleas from 11 species and subspecies (P = 46%; mean abundance = 1.44). The high parasitism rates obtained were consistent with previous records for other arid regions, suggesting that Patagonia favours the survival and development of Siphonaptera. Host geographic range and abundance were related to the parasitological indexes: host species with high-density populations had the highest mean flea abundance and prevalence, whereas widely distributed hosts had the highest richness and diversity of flea species. Our results contribute to the knowledge of the flea–host–environment complex. Our analysis of flea distributions and parasitism rate in Central Patagonia may be useful in epidemiological studies of flea-borne diseases and provide a basis for implementing surveillance systems for better risk assessment of emerging zoonoses in the region.

scholarly journals A New Multiplex Real-Time RT-PCR for Simultaneous Detection and Differentiation of Avian Bornaviruses

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1358
Author(s):  
Brigitte Sigrist ◽  
Jessica Geers ◽  
Sarah Albini ◽  
Dennis Rubbenstroth ◽  
Nina Wolfrum
Keyword(s):  
Real Time ◽  
Simultaneous Detection ◽  
Epidemiological Studies ◽  
Virus Species ◽  
Rt Pcr ◽  
P Gene ◽  
Field Samples ◽  
Causative Agents ◽  
Species Specific ◽  
Proventricular Dilatation Disease

Avian bornaviruses were first described in 2008 as the causative agents of proventricular dilatation disease (PDD) in parrots and their relatives (Psittaciformes). To date, 15 genetically highly diverse avian bornaviruses covering at least five viral species have been discovered in different bird orders. Currently, the primary diagnostic tool is the detection of viral RNA by conventional or real-time RT-PCR (rRT-PCR). One of the drawbacks of this is the usage of either specific assays, allowing the detection of one particular virus, or of assays with a broad detection spectrum, which, however, do not allow for the simultaneous specification of the detected virus. To facilitate the simultaneous detection and specification of avian bornaviruses, a multiplex real-time RT-PCR assay was developed. Whole-genome sequences of various bornaviruses were aligned. Primers were designed to recognize conserved regions within the overlapping X/P gene and probes were selected to detect virus species-specific regions within the target region. The optimization of the assay resulted in the sensitive and specific detection of bornaviruses of Psittaciformes, Passeriformes, and aquatic birds. Finally, the new rRT-PCR was successfully employed to detect avian bornaviruses in field samples from various avian species. This assay will serve as powerful tool in epidemiological studies and will improve avian bornavirus detection.

scholarly journals Host density predicts the probability of parasitism by avian brood parasites

2019 ◽  
Vol 374 (1769) ◽  
pp. 20180204 ◽  
Author(s):  
Iliana Medina ◽  
Naomi E. Langmore
Keyword(s):  
Spatial Distribution ◽  
Reproductive Success ◽  
Host Species ◽  
Field Data ◽  
Host Density ◽  
Brood Parasites ◽  
Parasitism Rates ◽  
Analyse Data ◽  
First Time ◽  
Determining Factor

The spatial distribution of hosts can be a determining factor in the reproductive success of parasites. Highly aggregated hosts may offer more opportunities for reproduction but can have better defences than isolated hosts. Here we connect macro- and micro-evolutionary processes to understand the link between host density and parasitism, using avian brood parasites as a model system. We analyse data across more than 200 host species using phylogenetic comparative analyses and quantify parasitism rate and host reproductive success in relation to spatial distribution using field data collected on one host species over 6 years. Our comparative analysis reveals that hosts occurring at intermediate densities are more likely to be parasitized than colonial or widely dispersed hosts. Correspondingly, our intraspecific field data show that individuals living at moderate densities experience higher parasitism rates than individuals at either low or high densities. Moreover, we show for the first time that the effect of host density on host reproductive success varies according to the intensity of parasitism; hosts have greater reproductive success when living at high densities if parasitism rates are high, but fare better at low densities when parasitism rates are low. We provide the first evidence of the trade-off between host density and parasitism at both macro- and micro-evolutionary scales in brood parasites. This article is part of the theme issue ‘The coevolutionary biology of brood parasitism: from mechanism to pattern’.

Regressive evolution of an effector following a host jump in the Irish Potato Famine Pathogen Lineage

2021 ◽  
Author(s):  
Erin K. Zess ◽  
Yasin F. Dagdas ◽  
Esme Peers ◽  
Abbas Maqbool ◽  
Mark J. Banfield ◽  
...  
Keyword(s):  
Host Species ◽  
Irish Potato ◽  
Sequence Motif ◽  
New Host ◽  
Regressive Evolution ◽  
Host Environment ◽  
Host Jump ◽  
Potato Famine ◽  
Irish Potato Famine ◽  
New Host Species

AbstractIn order to infect a new host species, the pathogen must evolve to enhance infection and transmission in the novel environment. Although we often think of evolution as a process of accumulation, it is also a process of loss. Here, we document an example of regressive evolution in the Irish potato famine pathogen (Phytophthora infestans) lineage, providing evidence that a key sequence motif in the effector PexRD54 has degenerated following a host jump. We began by looking at PexRD54 and PexRD54-like sequences from across Phytophthora species. We found that PexRD54 emerged in the common ancestor of Phytophthora clade 1b and 1c species, and further sequence analysis showed that a key functional motif, the C-terminal ATG8-interacting motif (AIM), was also acquired at this point in the lineage. A closer analysis showed that the P. mirabilis PexRD54 (PmPexRD54) AIM appeared unusual, the otherwise-conserved central residue mutated from a glutamate to a lysine. We aimed to determine whether this PmPexRD54 AIM polymorphism represented an adaptation to the Mirabilis jalapa host environment. We began by characterizing the M. jalapa ATG8 family, finding that they have a unique evolutionary history compared to previously characterized ATG8s. Then, using co-immunoprecipitation and isothermal titration calorimetry assays, we showed that both full-length PmPexRD54 and the PmPexRD54 AIM peptide bind very weakly to the M. jalapa ATG8s. Through a combination of binding assays and structural modelling, we showed that the identity of the residue at the position of the PmPexRD54 AIM polymorphism can underpin high-affinity binding to plant ATG8s. Finally, we conclude that the functionality of the PexRD54 AIM was lost in the P. mirabilis lineage, perhaps owing to as-yet-unknown pressure on this effector in the new host environment.Author SummaryPathogens evolve in concert with their hosts. When a pathogen begins to infect a new host species, known as a “host jump,” the pathogen must evolve to enhance infection and transmission. These evolutionary processes can involve both the gain and loss of genes, as well as dynamic changes in protein function. Here, we describe an example of a pathogen protein that lost a key functional domain following a host jump, a salient example of “regressive evolution.” Specifically, we show that an effector protein from the plant pathogen Phytopthora mirabilis, a host-specific lineage closely related to the Irish potato famine pathogen Phytopthora infestans, has a derived amino acid polymorphism that results in a loss of interaction with certain host machinery.

scholarly journals Development of a Rapid, Efficient, Intelligent and Cost-Saving Tool to Diagnose Pasteurella Multocida by Using Whole Genome Sequence and Genotypes of Pasteurella Multocida From Different Hosts

2020 ◽  
Author(s):  
Zhong Peng ◽  
Junyang Liu ◽  
Wan Liang ◽  
Fei Wang ◽  
Li Wang ◽  
...  
Keyword(s):  
Cost Saving ◽  
Host Species ◽  
Pasteurella Multocida ◽  
Epidemiological Studies ◽  
Whole Genome Sequence ◽  
Clinical Settings ◽  
Whole Genome ◽  
Genome Sequences ◽  
Host Tropism ◽  
Tropism Prediction

Abstract Background: Different typing systems including capsular genotyping, lipopolysaccharide (LPS) genotyping, multilocus sequence typing (MLST), and virulence genotyping based on the detection of different virulence factor-encoding gene (VFG) profiles have been applied to characterize Pasteurella multocida strains from different host species. However, these methods require much time and effort in laboratories. Particularly, relying on one of these methods is difficult to address the biology of P. multocida from host species. Recently, we found that assigning P. multocida strains according to the combination of their capsular, LPS, and MLST genotypes (marked as capsular genotype: LPS genotype: MLST genotype) could help address the biological characteristics of P. multocida circulation in multiple hosts. However, it is still lack of a rapid, efficient, intelligent and cost-saving tool to diagnose P. multocida according to this system. Results: We have developed an intelligent genotyping and host tropism prediction tool PmGT for P. multocida strains according to their whole genome sequences by using machine learning and web 2.0 technologies. By using this tool, the capsular genotypes, LPS genotypes, and MLST genotypes as well as the main VFGs of P. multocida isolates in different host species were determined based on whole genome sequences. The results revealed a closer association between the genotypes and pasteurellosis rather than between genotypes and host species. Finally, we also used PmGT to predict the host species of P. multocida strains with the same capsular: lipopolysaccharide: MLST genotypes. Conclusions: With the advent of high-quality, inexpensive DNA sequencing, this platform represents a more efficient and cost-saving tool for P. multocida diagnosis in both epidemiological studies and clinical settings.

scholarly journals Diversity of Pectobacteriaceae Species in Potato Growing Regions in Northern Morocco

2020 ◽  
Vol 8 (6) ◽  
pp. 895 ◽  
Author(s):  
Saïd Oulghazi ◽  
Mohieddine Moumni ◽  
Slimane Khayi ◽  
Kévin Robic ◽  
Sohaib Sarfraz ◽  
...  
Keyword(s):  
Species Diversity ◽  
Complete Genome ◽  
Draft Genome ◽  
Epidemiological Studies ◽  
Gene Marker ◽  
Oxford Nanopore ◽  
Causative Agents ◽  
Genome Analyses ◽  
Oxford Nanopore Technologies

Dickeya and Pectobacterium pathogens are causative agents of several diseases that affect many crops worldwide. This work investigated the species diversity of these pathogens in Morocco, where Dickeya pathogens have only been isolated from potato fields recently. To this end, samplings were conducted in three major potato growing areas over a three-year period (2015–2017). Pathogens were characterized by sequence determination of both the gapA gene marker and genomes using Illumina and Oxford Nanopore technologies. We isolated 119 pathogens belonging to P. versatile (19%), P. carotovorum (3%), P. polaris (5%), P. brasiliense (56%) and D. dianthicola (17%). Their taxonomic assignation was confirmed by draft genome analyses of 10 representative strains of the collected species. D. dianthicola were isolated from a unique area where a wide species diversity of pectinolytic pathogens was observed. In tuber rotting assays, D. dianthicola isolates were more aggressive than Pectobacterium isolates. The complete genome sequence of D. dianthicola LAR.16.03.LID was obtained and compared with other D. dianthicola genomes from public databases. Overall, this study highlighted the ecological context from which some Dickeya and Pectobacterium species emerged in Morocco, and reported the first complete genome of a D. dianthicola strain isolated in Morocco that will be suitable for further epidemiological studies.

Description of the helminth communities of sympatric rodents (Muroidea: Cricetidae) from the Atlantic Forest in northeastern Argentina

Zootaxa ◽  
2017 ◽  
Vol 4337 (2) ◽  
pp. 243 ◽  
Author(s):  
GUILLERMO PANISSE ◽  
MARÍA DEL ROSARIO ROBLES ◽  
MARÍA CELINA DIGIANI ◽  
JULIANA NOTARNICOLA ◽  
CARLOS GALLIARI ◽  
...  
Keyword(s):  
Atlantic Forest ◽  
Host Species ◽  
Diversity Index ◽  
New Host ◽  
Mean Intensity ◽  
Helminth Communities ◽  
Ecological Aspects ◽  
Northeastern Argentina

Taxonomic and ecological aspects of the helminths found in the assemblage of sigmodontine rodents (Cricetidae-Muroidea) of the Atlantic Forest in Argentina are studied in this paper. The following species Akodon montensis, Brucepattersonius sp. and Thaptomys nigrita (Tribe Akodontini), as well as, Euryoryzomys russatus, Nectomys squamipes, Oligoryzomys nigripes, and Sooretamys angouya (Tribe Oryzomyini) are analyzed. A complete taxonomic list with a total of 25 species of helminths, including Digenea (Dicrocoeliidae), Cestoda (Hymenolepididae) and Nematoda (Trichuridae, Capillariidae, Cooperidae, Helligmonellidae, Oxyuridae, and Onchocercidae) is provided. Twenty new host and locality records for Misiones, Argentina, are reported and the results of the ecological descriptors of component communities are given. The highest value of richness was observed for A. montensis (S=8) and E. russatus (S=7). The diversity index (H´) reached values between 1.03 and 1.39 in all rodents, with the exception of N. squamipes that reached 0.75. The equitability indeces with highest value were observed for T. nigrita and E. russatus. The Berger-Parker index of dominance was similar for all host species. The highest prevalence, mean abundance and mean intensity values corresponded to Nippostrongylinae, followed by Syphacinii. This survey constitutes the report with the most diverse parasitic assemblage of rodents described for the Atlantic Forest ecoregion and for Argentina. 

Etio-Epidemiological Studies on Diarrhoea in Cattle and Buffalo Calves

2020 ◽  
Author(s):  
S K Sharma ◽  
Monika Joshi
Keyword(s):  
Winter Season ◽  
Epidemiological Studies ◽  
Economic Losses ◽  
Buffalo Calves ◽  
Salmonella Spp ◽  
E Coli ◽  
Cryptosporidium Spp ◽  
Faecal Samples ◽  
Eimeria Spp ◽  
Causative Agents

Calf diarrhoea is the most commonly encountered disease syndrome and significant cause of economic losses in dairy industry. Present investigation was undertaken to find out the prevalence of causative agents of diarrhoea in the bovine calves for a period of one year. The effect of age, sex, season and parity of dam was also studied. E. coli was the major organism (86.00 %) observed in the faecal samples of the diarrhoeic calves followed by rotavirus, Eimeria spp. and Amphistomes (15.00 % each); Toxocara spp. (12.00 %); Strongyles (9.00 %); Cryptosporidium spp. (6.00 %); Trichuris spp. (5.00 %); and Salmonella spp. and Strongyloides spp. (3.00 % each). The prevalence of rotavirus, Cryptosporidium spp. and Eimeria spp. was found significantly higher in buffalo calves and crossbred calves than cow calves and Gir / local non-descript calves, respectively. The prevalence of Toxocara spp., Amphistomes and Strongyles in diarrhoeic buffalo calves was significantly higher than cow calves. Highest prevalence of E. coli and rotavirus was observed in faecal samples of diarrhoeic calves of 0-15 days age group. Rotavirus was not detected in faecal samples of diarrhoeic calves above 60 days age. The susceptibility of bovine calves for E. coli and rotavirus was found decreased with the advancement of the age. The prevalence of Salmonella spp. in diarrhoeic faecal samples of bovine calves was observed only in 16-60 days age whereas Cryptosporidium spp. was found only in 0-30 days age. The most of the parasitic infestations were observed after 30 days of age in calves. The calves of both sexes were equally susceptible to different causative agents of diarrhoea. The prevalence of E. coli and most of the helminth ova in the faecal samples of diarrhoeic calves was found maximum during rainy season whereas the rotavirus was observed mostly during winter season. The prevalence of E. coli, Salmonella spp., rotavirus and Cryptosporidium spp. was found highest in the faecal samples of the diarrhoeic calves of first or second parity dams.

scholarly journals Prevalence, Severity and Causative Agents of Dieback in Calotropis procera in Semi-Arid Regions of Kenya

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Brexidis Mandila ◽  
Kenneth Odhiambo ◽  
Alice Muchugi ◽  
Daniel Nyamai ◽  
Damaris Musyoka
Keyword(s):  
Arid Regions ◽  
Calotropis Procera ◽  
Causative Agents ◽  
Semi Arid

scholarly journals Hijacking and Use of Host Kinases by Chlamydiae

Pathogens ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1034
Author(s):  
Prakash Sah ◽  
Erika I. Lutter
Keyword(s):  
Host Cell ◽  
Intracellular Pathogen ◽  
Host Proteins ◽  
Sexually Transmitted ◽  
Obligate Intracellular ◽  
Host Cell Apoptosis ◽  
Survival And Development ◽  
Causative Agents ◽  
Cell Processes ◽  
Obligate Intracellular Pathogen

Chlamydia species are causative agents of sexually transmitted infections, blinding trachoma, and animal infections with zoonotic potential. Being an obligate intracellular pathogen, Chlamydia relies on the host cell for its survival and development, subverting various host cell processes throughout the infection cycle. A key subset of host proteins utilized by Chlamydia include an assortment of host kinase signaling networks which are vital for many chlamydial processes including entry, nutrient acquisition, and suppression of host cell apoptosis. In this review, we summarize the recent advancements in our understanding of host kinase subversion by Chlamydia.

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