Host Sex Research Articles

Factors Influencing Tissue Cyst Yield in a Murine Model of Chronic Toxoplasmosis.

Recent advances into the unique biology of Toxoplasma tissue cysts and the bradyzoites they house necessitate optimization of tissue cyst recovery from infected mouse brains. Here, we present data from 83 tissue cyst purifications of Type II ME49 tissue cysts in CBA/J mice performed over a period of 3 years. The effects of infection with both tissue culture tachyzoites as well as ex vivo tissue cysts were assessed. Significant mortality was restricted to tachyzoite infections with female mice being more susceptible. Infection with tissue cysts was associated with both lower overall symptomology and mortality, exhibiting no sex bias. Cumulatively, host sex did not impact overall tissue cyst yields, although tachyzoite-initiated infections generated significantly higher yields compared to tissue cyst-initiated infections. Notably, serial passage of tissue cysts was accompanied with a decreasing trend for subsequent cyst recovery. The time of tissue cyst harvest, a potential reflection of bradyzoite physiological state, had no significant impact on subsequent cyst yield at the selected time points. In aggregate, these data reveal the considerable heterogeneity associated with tissue cyst yield, making the design of adequately powered experiments critical. This is particularly the case for drug studies where overall tissue cyst burden is currently the primary and often sole metric of efficacy, as the data presented here demonstrate that cyst recovery between preparations of untreated animals can mirror and even exceed the reported effects of drug treatment.

Co-infection patterns in the ectoparasitic community affecting the Iberian ibex Capra pyrenaica

BackgroundSarcoptic mange is one of the main parasitic diseases affecting the Iberian ibex Capra pyrenaica. Scabietic animals suffer a decline in body condition and reproductive fitness and in severe cases may die. Although several previous studies of the pathology of this disease and the physiological changes it produces in ibex have been carried out in recent years, our knowledge of the relationship between Sarcoptes scabiei and other ectoparasites of this host is still limited.MethodsWe analysed 430 Iberian ibex skin samples. Ectoparasites were removed, counted and identified. Mite (S. scabiei) numbers were obtained after digesting the skin samples in a 5% KOH solution. We modelled mite numbers in terms of host sex and age, site, year, season and the presence of other ectoparasites such as ticks and lice using generalized linear mixed models (GLMMs) and ectoparasite co-occurrence patterns using two different models: the probabilistic model species co-occurrence and the generalized linear latent variable model (GLLVM).ResultsThe ectoparasite community was mainly composed of S. scabiei, six ticks (Haemaphysalis sulcata, Haemaphysalis punctata, Rhipicephalus bursa, Rhipicephalus turanicus, Dermacentor marginatus and Ixodes ricinus) and two lice (Bovicola crassipes and Linognathus stenopsis). Adult male ibex harboured more mites than females. Mite numbers varied greatly spatially and seasonally and increased with the presence of other parasites. Some positive co-occurrence relationships between pairs of different ectoparasites were observed, particularly between ticks. The presence of S. scabiei negatively affected lice and H. sulcata numbers.ConclusionsSarcoptic mange has spread above all in ibex populations in and around the Mediterranean Basin, where it is now found in almost a third of its host’s range. Mite numbers varied seasonally and spatially and were higher in male hosts. The presence of S. scabiei had a negative effect on lice numbers but favoured the presence of ticks.Graphical

Digenetic Parasite Diversity of the Coastal Trevally Fish, Carangoides caeruleopinnatus: Factors Influencing Parasitism

Background: Carangidae is a family of ray-finned fish within the order Carangiformes which are invaded by different parasite species and the rate of parasitism changed regarding different factors. This study aimed to provide information about the relationship between fish size and sex on the parasites that infect fish within the family Carangidae in Saudi Arabia. Methods: A total of 90 Carangoides caeruleopinnatus specimens were collected from the Red Sea. The size of the fish was taken in grams (for weights) and centimeters (for lengths), respectively, as well as fish sex was determined. Fish organs were examined for parasitic infection. Result: There is a relationship between the length, weight and sex of fish hosts on the incidence of parasitic infection in the examined fish. Larger fish size is heavily parasitized than smaller ones which provide a greater surface for infection. In addition, the mean weight of uninfected samples was considerably higher than infected which suggested a weight loss because of parasitic infection. Parasitism in fish has been reported to be sex-biased, with males suffering greater susceptibility than female fish. This study reflects the rate of parasitism in the coastal trevally, Carangoides caeruleopinnatus, concerning fish length as well as their sex.

Sex-typing of ingested human blood meal in Anopheles stephensi mosquito based on the amelogenin gene.

Identifying the sex of human hosts of insect disease vectors, using PCR amplification of the amelogenin gene (AMEL) from the ingested blood meal is an increasingly useful technique for epidemiological studies of vector-borne diseases, as well as within the criminal justice system. Detection of DNA from ingested blood is influenced by the choice of DNA extraction method, genomic target region, type and length of PCR, and rate of degradation in the DNA samples over time. Here, we have tested two types of PCR (i.e. conventional and nested), producing differently-sized PCR products, in time-course assays targeting the human AMEL gene in Anopheles stephensi mosquitoes that were fed on human male and female blood. The fed female mosquitoes were allowed to digest at 28°C for times ranging from 0 to 120h. Three AMEL primer pairs were used to amplify three sequences that were 977, 539, and 106 bp for the X chromosome and 790, 355, and 112 bp for Y. We found that time since feeding had a significant negative effect on the success of PCR amplification. The shortest fragments (106 and 112 bp) were amplified for the longest time after blood feeding (up to 60h), whereas the medium and longest loci were not amplified by conventional PCR even at 0h. However, the nested PCR protocol, targeting the medium sequence, could detect small amounts of human DNA up to 36h (1.5 days) after the blood meal. The shortest PCR assay standardized herein successfully detected small amounts of human DNA in female mosquitoes up to 60h after the blood meal. This assay represents a promising tool for identifying the sex of the human host from the blood meal in field-collected female mosquitoes.

Sex differences in ILC2 function in influenza result from imprinted donor sex intrinsic factors independent of host sex in competitive female-male bone marrow chimeras

Abstract Historical influenza pandemics and the SARS-CoV-2 pandemic revealed gender differences in morbidity of respiratory virus infections. In human or murine influenza A virus (IAV) infection, females of reproductive age generate stronger innate and adaptive antiviral responses leading to immunopathology, while elderly males often experience more severe disease. Sex hormone levels play a role in this disparity, yet little is known about cell intrinsic regulation of immune cells by estrogen or androgen receptors (AR). Lung resident type 2 innate lymphocytes (ILC2s) express high levels of AR, a nuclear hormone receptor that regulates chromatin via epigenetic modifications. While female lungs contain higher ILC2 numbers in homeostasis, we showed that ILC2s in females were preferentially functionally suppressed during IAV infection, whereas ILC2s in males retained robust type 2 function, including IL-5 production. Here, we determined if sex differences in pulmonary ILC2s result from extrinsic factors present in host environments or from imprinted donor-intrinsic factors. We set up competitive bone marrow chimeras by transferring a mix of female and male lineage-depleted bone marrow cells into either male or female hosts. Female hosts harbored more pulmonary ILC2s than male hosts, suggesting the extrinsic sex hormone environment regulates ILC2 numbers. Upon IAV infection, an increased fraction of ILC2s from male donors retained high IL33R expression and produced IL-5, regardless of host sex, suggesting donor sex-intrinsic factors regulate the canonical ILC2 functional response. We are now testing the hypothesis that androgens/AR activity epigenetically imprint genes regulating type 2 function in male ILC2s upon sexual maturity.

Prevalence, Molecular Characterization, and Ecological Associations of Filarioid Helminths in a Wild Population of Blue Tits (Cyanistes caeruleus)

Filarioid nematodes (commonly known as filarial worms) are known to impact human and domestic animal health, but studies examining their ecological relevance and impacts on wildlife are still underrepresented. In the case of birds, microfilariae are typically found at low prevalence, but they may negatively affect some fitness-related traits. Here, we study the prevalence and associations of microfilariae in a wild population of blue tits (Cyanistes caeruleus) inhabiting a woodland comprising different forestry formations. In addition, we characterize the filarioid lineages through the cytochrome c oxidase subunit I (COI) gene sequence. We found a moderate prevalence of microfilariae in the blue tit population (9.4%) and that the presence of such parasites was negatively associated with host body mass. Neither forest type nor host sex influenced microfilariae presence. Phylogenetic analyses revealed the presence of five filarioid lineages clustered in the Onchocercidae family—four out of five lineages clustered in the Splendidofilaria clade, while the remaining lineage could not be clearly assigned to a genus. In addition, this is the first study examining the filarioid lineages infecting the blue tit. Our results suggest that hosts in poorer body condition, in terms of lower body mass, are more susceptible to be parasitized by filarioid nematodes and call for further genetic studies of these parasites.

Host-related and environmental factors influence long-term ectoparasite infestation dynamics of mouse lemurs in northwestern Madagascar.

Parasite infestations depend on multiple host-related and environmental factors. In the case of ectoparasites, which are exposed to the environment beyond the host, an impact of climate, expressed by seasonal or yearly variations, can be expected. However, long-term dynamics of ectoparasite infestations are rarely studied in nonhuman primates. We investigated the yearly variations in ectoparasite infestations of two small primates, the gray (Microcebus murinus) and the golden-brown (Microcebus ravelobensis) mouse lemur. For a more comprehensive evaluation, we also analyzed the potential effects of yearly and monthly climatic variation (temperature, rainfall) in addition to habitat, host sex, age, species, and body mass, on ectoparasite infestation. Individuals of both host species were sampled in two study sites within the Ankarafantsika National Park in northwestern Madagascar during several months (March-November) and across 4 years (2010, 2011, 2015, 2016). Our results show significant monthly and yearly variations in the infestation rates of three native ectoparasite taxa (Haemaphysalis spp. ticks, Schoutedenichia microcebi chigger mites, Lemurpediculus spp. sucking lice) and in ectoparasite species richness in both mouse lemur species. In addition, significant impacts of several host-related (species, sex, body mass) and environmental factors (habitat, temperature, rainfall) were found, but with differences in relevance for the different parasite taxa and partly deviating in their direction. Although some differences could be attributed to either permanent or temporary presence of the parasites on the host or to ecological differences between the host species, the lack of specific knowledge regarding the life cycle and microhabitat requirements of each parasite taxon precludes a complete understanding of the factors that determine their infestation dynamics. This study demonstrates the presence of yearly and monthly dynamics in lemur-parasite interactions in tropical, seasonal, dry deciduous forests in Madagascar, which call out for broad ecological long-term studies focusing both on primate hosts and their parasites.

Characteristics of phenotypic antibiotic resistance of Helicobacter pylori and its correlation with genotypic antibiotic resistance: A retrospective study in Ningxia

Geographic differences exist in the antibiotic resistance patterns of Helicobacter pylori. Personalized treatment regimens based on local or individual resistance data are essential. We evaluated the current status of H.pylori resistance in Ningxia, analyzed resistance-related factors, and assessed the concordance of phenotypic and genotypic resistance. Strains were isolated from the gastric mucosa of patients infected with H.pylori in Ningxia and relevant clinical information was collected. Phenotypic antibiotic susceptibility assays (Kirby-Bauer disk diffusion) and antibiotic resistance gene detection (Sanger sequencing) were performed. We isolated 1955 H.pylori strains. The resistance rates of H.pylori to amoxicillin, levofloxacin, clarithromycin, and metronidazole were 0.9%, 42.4%, 40.4%, and 94.2%, respectively. Only five tetracycline-resistant and one furazolidone-resistant strain were identified. Overall, 3.3% of the strains were sensitive to all six antibiotics. Multidrug-resistant strains accounted for 22.9%, of which less than 20% were from Wuzhong. Strains isolated from women and patients with nonulcerative disease had higher rates of resistance to levofloxacin and clarithromycin. Higher rates of resistance to metronidazole, levofloxacin, and clarithromycin were observed in the older age group than in the younger age group. The kappa coefficients of phenotypic resistance and genotypic resistance for levofloxacin and clarithromycin were 0.830 and 0.809, respectively, whereas the remaining antibiotics showed poor agreement. H.pylori antibiotic resistance is severe in Ningxia. Therefore, furazolidone, amoxicillin, and tetracycline are better choices for the empirical therapy of H.pylori infection in this region. Host sex, age, and the presence of ulcerative diseases may affect antibiotic resistance of the bacteria. Personalized therapy based on genetic testing for levofloxacin and clarithromycin resistance may be a future direction for the eradication therapy of H.pylori infection in Ningxia.

Male-Biased Parasitism of Brandt's Voles (Lasiopodomys brandtii) in Inner Mongolia, China.

The abundance and prevalence of parasitic infection often vary in different host sexes, and this phenomenon has been named sex-biased parasitism. Brandt's voles are the dominant rodent species in typical steppe habitat and are widely distributed in Inner Mongolia, China, but the prevalence of parasites in Brandt's voles are poorly reported. In this study, we investigated the prevalence of six intestinal parasites in Brandt's voles in May, June, July, and August 2022 around the Xilingol Grassland in Inner Mongolia, China. The results showed that Syphacia obvelata, Aspiculuris tetraptera, and Trichostrongylidae family were the dominant intestinal parasites in Brandt's voles that we captured in this study, and the infection rates of the three parasites were significantly higher in males than females, which showed obvious male-biased parasitism. Season and human activities such as grazing had no significant effect on the infection rates for different parasites, while the parasite reproduction level was higher when the ambient temperature was around 18 °C. Sexual size dimorphism was ubiquitous in Brandt's voles, and it was mainly manifested by the differences in body weight and length between males and females. Simple linear regression analysis showed a significant positive correlation between bodyweight and parasite infection rates, so the sex-biased parasitism in Brandt's voles could be explained by the body size hypothesis, as a larger body could provide more ecological niches for parasitic infection.

Abstract 645: Impact of sex differences on cross-talk between the gut microbiome, CEACAMs, and TGF-β signaling in cancers

Abstract Background: Sex differences, microbiome alterations and obesity are prominent factors modulating gastrointestinal (GI) cancers, such as colorectal cancer (CRC) and hepatocellular carcinoma (HCC). However, there is a limited understanding of the interactions between intestinal epithelial and immune cells that participate in the regulation of the microbiome and the prevention or promotion of inflammation and the development of cancer. CEACAM proteins are immune and epithelial cell regulators, and some CEACAMs (CEACAM1, 3, 5, and 6) bind to pathogenic microbes. CEACAMs and mutations of the encoding genes are potential drivers of microbiome changes through altered regulation of host-immune response, through a mechanism that we hypothesize involves TGF-β signaling. We found that genetic alterations in CEACAM-encoding genes correlate with scores of TGF-β pathway activity in GI cancers in The Cancer Genome Atlas (TCGA). Furthermore, nearly 40% of human GI cancers have genetic alterations in components and regulators of the TGF-β pathway. We, therefore, investigated crosstalk between pathogen-binding CEACAM1, the gut microbiome, and the multifunctional intrinsically disordered protein βII-spectrin (SPTBN1), a Smad3 adaptor in driving CRC and liver cancers. Methods: The DNA from fecal samples collected from wild-type mice or TGF-β signaling-deficient mice Smad4+/-Sptbn1+/- were analyzed through shotgun metagenomics sequencing to identify changes in gut microbiota composition. We examined CEACAM expression, changes in the T cell populations, liver inflammation, and cancer in tissues from liver-specific βII-spectrin knockout (LSKO) mice fed a Western diet. Results: Mice heterozygous for the Sptbn1 gene (Sptbn1+/-) combined with heterozygosity of Smad4 (Smad4+/-Sptbn1+/-) spontaneously developed GI cancers, in the C57BL/6J genetic background. These mice exhibit an increased bacterial species associated with CRC in humans (C. septicum) and decreased commensal gut microbes associated with a healthy microbiome (B. vulgatus, P. distasonis). In addition, male Sptbn1+/- mice spontaneously developed HCC and showed reduced regulatory T (Treg) cells, whereas female mice did not, suggesting that βII-spectrin has a role in immune cell homeostasis that may affect tumor suppression. Single cell analyses revealed that Ceacam1 expression decreases in hepatocytes in mice fed a Western diet. CEACAM1 levels are restored to normal in tissues from liver-specific βII-spectrin knockout (LSKO) mice. Furthermore, we observed diet-induced changes in the T cell populations, liver inflammation, and cancer are also blocked in LSKO mice. Conclusion: Our study highlights how two critical pathways, TGF-β signaling and immune mediators CEACAM1 and 5, can drive inflammation and cancer through microbiome alterations with host sex having marked impact on the relevant signaling pathways. Citation Format: Krishanu Bhowmick, Addison Klebanov, Sahara John, Xiaochun Yang, Xiyan Xiang, Anil Vegesna, Kazufumi Ohshiro, James M. Crawford, Nicole Beauchemin, Raja Mazumder, Keith A. Crandall, Lopa Mishra. Impact of sex differences on cross-talk between the gut microbiome, CEACAMs, and TGF-β signaling in cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 645.

Battle of the sexes: analysis of sex bias in host use and reporting practices in parasitological experiments

Experimental approaches are among the most powerful tools available to biologists, yet in many disciplines their results have been questioned due to an underrepresentation of female animal subjects. In parasitology, experiments are crucial to understand host-parasite interactions, parasite development, host immune responses, as well as the efficacy of different control methods. However, distinguishing between species-wide and sex-specific effects requires the balanced inclusion of both male and female hosts in experiments and the reporting of results for each sex separately. Here, using data from over 3600 parasitological experiments on helminth-mammal interactions published in the past four decades, we investigate patterns of male versus female subject use and result reporting practices in experimental parasitology. We uncover multiple effects of the parasite taxon used, the type of host used (rats and mice for which subject selection is fully under researcher control versus farm animals), the research subject area and the year of publication, on whether host sex is even specified, whether one or both host sexes have been used (and if only one then which one), and whether the results are presented separately for each host sex. We discuss possible reasons for biases and unjustifiable selection of host subjects, and for poor experimental design and reporting of results. Finally, we make some simple recommendations for increased rigour in experimental design and to reset experimental approaches as a cornerstone of parasitological research.

Individual variation in the avian gut microbiota: The influence of host state and environmental heterogeneity.

The gut microbiota have important consequences for host biological processes and there is some evidence that they also affect fitness. However, the complex, interactive nature of ecological factors that influence the gut microbiota has scarcely been investigated in natural populations. We sampled the gut microbiota of wild great tits (Parus major) at different life stages allowing us to evaluate how microbiota varied with respect to a diverse range of key ecological factors of two broad types: (1) host state, namely age and sex, and the life history variables, timing of breeding, fecundity and reproductive success; and (2) the environment, including habitat type, the distance of the nest to the woodland edge, and the general nest and woodland site environments. The gut microbiota varied with life history and the environment in many ways that were largely dependent on age. Nestlings were far more sensitive to environmental variation than adults, pointing to a high degree of flexibility at an important time in development. As nestlings developed their microbiota from one to two weeks of life, they retained consistent (i.e., repeatable) among-individual differences. However these apparent individual differences were driven entirely by the effect of sharing the same nest. Our findings point to important early windows during development in which the gut microbiota are most sensitive to a variety of environmental drivers at multiple scales, and suggest reproductive timing, and hence potentially parental quality or food availability, are linked with the microbiota. Identifying and explicating the various ecological sources that shape an individual's gut bacteria is of vital importance for understanding the gut microbiota's role in animal fitness.

A Review of the Host Plant Location and Recognition Mechanisms of Asian Longhorn Beetle.

The Asian longhorn beetle (ALB), Anoplophora glabripennis Motschulsky, is a polyphagous xylophage with dozens of reported host tree species. However, the mechanisms by which individuals locate and recognize host plants are still unknown. We summarize the current knowledge of the host plant list, host kairomones, odorant-binding proteins (OBPs) and microbial symbionts of this beetle and their practical applications, and finally discuss the host localization and recognition mechanisms. A total of 209 species (or cultivars) were reported as ALB host plants, including 101 species of higher sensitivity; host kairomones were preferentially bound to ALB recombinant OBPs, including cis-3-hexen-1-ol, δ-3-carene, nonanal, linalool, and β-caryophyllene. In addition, microbial symbionts may help ALB degrade their host. Complementarity of tree species with different levels of resistance may reduce damage, but trapping effectiveness for adults was limited using a combination of host kairomones and sex pheromones in the field. Therefore, we discuss host location behavior from a new perspective and show that multiple cues are used by ALB to locate and recognize host plants. Further research into host resistance mechanisms and visual signal recognition, and the interaction of sex pheromone synthesis, symbiont microbiota, and host plants may help reveal the host recognition mechanisms of ALBs.

Odorant-Binding Proteins and Chemosensory Proteins in Spodoptera frugiperda: From Genome-Wide Identification and Developmental Stage-Related Expression Analysis to the Perception of Host Plant Odors, Sex Pheromones, and Insecticides.

Spodoptera frugiperda is a worldwide generalist pest with remarkable adaptations to environments and stresses, including developmental stage-related behavioral and physiological adaptations, such as diverse feeding preferences, mate seeking, and pesticide resistance. Insects' odorant-binding proteins (OBPs) and chemosensory proteins (CSPs) are essential for the chemical recognition during behavioral responses or other physiological processes. The genome-wide identification and the gene expression patterns of all these identified OBPs and CSPs across developmental stage-related S. frugiperda have not been reported. Here, we screened for genome-wide SfruOBPs and SfruCSPs, and analyzed the gene expression patterns of SfruOBPs and SfruCSPs repertoires across all developmental stages and sexes. We found 33 OBPs and 22 CSPs in the S. frugiperda genome. The majority of the SfruOBP genes were most highly expressed in the adult male or female stages, while more SfruCSP genes were highly expressed in the larval or egg stages, indicating their function complementation. The gene expression patterns of SfruOBPs and SfruCSPs revealed strong correlations with their respective phylogenic trees, indicating a correlation between function and evolution. In addition, we analyzed the chemical-competitive binding of a widely expressed protein, SfruOBP31, to host plant odorants, sex pheromones, and insecticides. Further ligands binding assay revealed a broad functional related binding spectrum of SfruOBP31 to host plant odorants, sex pheromones, and insecticides, suggesting its potential function in food, mate seeking, and pesticide resistance. These results provide guidance for future research on the development of behavioral regulators of S. frugiperda or other environmentally friendly pest-control strategies.

Helminths of freshwater turtles in Northeastern Brazil: parasite–host–environment relationships

ABSTRACT The parasitic fauna of reptiles is considered understudied compared to that of other vertebrates and is even less well known than the parasitic fauna of chelonians. Yet parasites are considered one of the main controllers of host populations because they can strongly impact population structure and species diversity. The objective of the present study was to identify the helminth fauna infecting freshwater turtles Phrynops geoffroanus and Mesoclemmys tuberculata, to evaluate the effects of host features (body mass and sex) and seasonality (dry and rainy seasons) on the abundance of parasites, and to compare infection rates in each host species between different biomes (Caatinga and Atlantic Forest) in an area of Northeastern Brazil. We found seven species of helminths that belong to Nematoda (Physaloptera sp., Serpinema amazonicus, Serpinema monospiculatus and Spiroxys figueiredoi), Cestoda (unidentified specimen), Digenea (Echinostomatidae) and Monogenea (Polystomoides brasiliensis). For both freshwater turtle species, we did not find a significant difference in the abundance of helminths related to the maximum carapace length, body mass or host sex; however, males had higher prevalence than females, while females presented greater abundance when infected. We observed significant differences in the infection levels between biomes and between seasons (dry and rainy), where the Atlantic Forest specimens showed higher infection rates compared to the Caatinga and the highest rates occurred in the dry season. The main parasitological parameters observed in P. geoffroanus and M. tuberculata showed that the studied biomes directly influenced the levels of parasitic infection. Variations in habitat characteristics can directly influence patterns of helminth diversity and abundance, and interactions between these characteristics can generate differences in parasitism rates of the same host species in different environments.

Forest Matters Most for Hirsutiella zachvatkini (Schluger, 1948): A Survey of Rodent Infestation in Four Localities within the Mazury Lake District, NE Poland

The family Trombiculidae encompasses numerous and widespread mites, the larvae of which are obligatory parasites of vertebrates. Our research objective was to assess how trombiculid burdens on rodents inhabiting three forested and one open area in NE Poland vary in relation to host identity, sex and body size, and how they are influenced by qualities of the habitat. Trapped rodents (n = 240) were measured, weighted and screened for ectoparasites. Apodemus flavicollis (n = 42) and Myodes glareolus (n = 173) harbored a total of 4652 Hirsutiella zachchvatkini larvae. Statistical tests revealed that both prevalence and abundance were significantly higher in voles (93%, 27 larvae/ind.) than in mice (14%, 0.24 larvae/ind.) but there was no effect of host sex. Among the localities, H. zachvatkini was most prevalent (98%) and abundant (41 larvae/ind.) in rodents from the deciduous mixed forest in Tałty compared to fallow land (2.6%, 0.13 larvae/ind.). The highest prevalence and abundance were found in bank voles; in this host species in Tałty, prevalence reached 100% and the mean abundance was >42 larvae/ind. Significant positive correlations were found between the body mass and body length of voles and the number of attached larvae. Our results confirm the sylvan nature of H. zachvatkini and its preference for bank voles inhabiting deciduous forests with rich and humid undergrowth. The lack of a sex bias and the moderate correlation between mite burden and host size are in line with observations already made on other rodent-associated Trombiculidae.

Multicompartmental traumatic injury induces sex-specific alterations in the gut microbiome.

Previous preclinical studies have demonstrated an altered gut microbiome after traumatic injury; however, the impact of sex on dysbiosis remains unknown. We hypothesized that the "pathobiome" phenotype induced by multicompartmental injuries and chronic stress is host sex specific with unique microbiome signatures. Male and proestrus female Sprague-Dawley rats (n = 8/group) aged 9 weeks to 11 weeks were subjected to either multicompartmental injury (PT) (lung contusion, hemorrhagic shock, cecectomy, bifemoral pseudofractures), PT plus 2 hours daily chronic restraint stress (PT/CS) or naive controls. Fecal microbiome was measured on Days 0 and 2 using high-throughput 16S rRNA sequencing and Quantitative Insights Into Microbial Ecology bioinformatics analyses. Microbial alpha-diversity was assessed using Chao1 (number of different unique species) and Shannon (species richness and evenness) indices. Beta-diversity was assessed using principle coordinate analysis. Intestinal permeability was evaluated by plasma occludin and lipopolysaccharide binding protein. Histologic evaluation of ileum and colon tissues was scored for injury by a blinded pathologist. Analyses were performed in GraphPad and R, with significance defined as p < 0.05 between males versus females. At baseline, females had significantly elevated alpha-diversity (Chao1, Shannon indices) compared with males ( p < 0.05) which was no longer present 2 days postinjury in PT and PT/CS. Beta-diversity also differed significantly between males and females after PT ( p = 0.01). At Day 2, the microbial composition in PT/CS females was dominated by Bifidobacterium , whereas PT males demonstrated elevated levels of Roseburia ( p < 0.01). The PT/CS males had significantly elevated ileum injury scores compared with females ( p = 0.0002). Plasma occludin was higher in PT males compared with females ( p = 0.004); plasma lipopolysaccharide binding protein was elevated in PT/CS males ( p = 0.03). Multicompartmental trauma induces significant alterations in microbiome diversity and taxa, but these signatures differ by host sex. These findings suggest that sex is an important biological variable that may influence outcomes after severe trauma and critical illness.

Arthropod Ectoparasites of Two Rodent Species Occurring in Varied Elevations on Tanzania’s Second Highest Mountain

Climate change causes organisms, including species that act as parasite reservoirs and vectors, to shift their distribution to higher altitudes, affecting wildlife infestation patterns. We studied how ectoparasite distributions varied with altitude using two rodent species, Montemys delectorum and Rhabdomys dilectus, at different elevations (1500-3500 m). The ectoparasites infesting the two rodent species were influenced by the host sex, species, and temperature. We expected host density to predict parasite infestation patterns, because hosts in higher densities should have more parasites due to increased contact between individuals. However, temperature, not host density, affected ectoparasite distribution. Since temperatures decrease with elevation, parasite prevalences and abundances were lower at higher elevations, highlighting that the cold conditions at higher elevations limit reproduction and development-this shows that higher elevation zones are ideal for conservation. The rodents and ectoparasite species described in this study have been reported as vectors of diseases of medical and veterinary importance, necessitating precautions. Moreover, Mount Meru is a refuge for a number of endemic and threatened species on the IUCN Red List. Thus, the parasitic infection can also be an additional risk to these critical species as well as biodiversity in general. Therefore, our study lays the groundwork for future wildlife disease surveillance and biodiversity conservation management actions. The study found a previously uncharacterized mite species in the Mesostigmata group that was previously known to be a parasite of honeybees. Further investigations may shed light into the role of this mite species on Mount Meru.

The influence of the host sex on parasitemia of parasite lineages belonging to Haemoproteus majoris in a natural bird community.

Immunological capability shows a sexual dimorphism in diverse animal species. Females are generally more immunocompetent than males, leading to the higher susceptibility of males to infection compared to females and thus greater infection-related pathology in males. These sex-differences in immunity remain understudied in birds. Here, we compared the percentage of parasitemia of three different parasite lineages belonging to the morphological species Haemoproteus majoris (namely, PARUS1, PHSIB1 and WW2) in terms of the sex of birds living in a natural community. We found that parasitemia (percentage of erythrocytes infected with parasites) of WW2 lineage, but not of the other two lineages of H. majoris, is higher in male birds compared to female birds. Similarly, we showed that the total parasitemia of these three H. majoris lineages is higher in male birds compared to female birds. Our study points out that male birds at the community level may be more susceptible to infection by certain parasites than female birds. We propose that sexual dimorphism in parasitemia of certain parasites in host birds might be more common than previously thought, similar to what is observed in other species, influencing host population dynamics in a sex-specific manner. Therefore, it can be speculated that infection by certain parasites might differentially affect male and female birds, possibly resulting in a bias in survival rates between sexes due to infections, in certain contexts.

GIS BASED FREQUENCY DISTRIBUTION OF WINGLESS INSECTS INFESTING DOMESTIC POPULATION OF DOGS IN LAHORE, PUNJAB, PAKISTAN

The intent of the present study was conducted (January, 2020 to December, 2020) to estimate the prevalence of wingless insects in dog population and to identify the potential risks factors in selected areas of Lahore, Punjab, Pakistan. Results of the study revealed an overall prevalence of wingless insects 50.16% (1204/2400) in dogs of study area. Among various insects, fleas were found predominant (28.5%; 684/2400; P&lt;0.05) as compared to lice (21.66%; 520/2400). Among the reported species 4 were wingless insects (Ctenocepahlides (Ct.) felis, Ct, canis, Linognathus setosus and Trichodectes canis). Breed, age and sex of host were not found to be related with risk factors (P&gt;0.05) affecting incidence of wingless insects. These inscets effect different body parts differently as highest prvelance was noted at neck (15%) and back (11.5%) followed by abdomen (10%) and ear (7.4%).Prevelence of the ectoparasites was found to be 6.2% at forelegs and 4% in congenital area, 4% around the shoulder and 6% around the hind legs, however, tail area was minimally affected (1.2%). Prevelance of Ct. felis was noted to be 35.96, Ct. canis 68.43%, Linognathus setosus 21.1% and Trichodectes canis 78.8%. Town wise incidences were found to be highest in Shalimar Town (62.91%) followed by Wagha Town (59.58%), Aziz Bhatti(59.16%), Data Ganj Bakhsh (55.41%), Nishtar Town (46.66%), Samanabad (44.3%), Iqbal Town (43.6%), Ravi Town (42%), Lahore Cantonment (41.6%) and Gulberg (40.4%). Rate of ectoparasites infestation was observed higher (P&lt;0.05) in stray dogs (80.36%) followed by guard dogs (63.7%), hunting dogs (37.5%) and pet dogs (35.66%). Amongst the different seasons, rainy season showed higher lice prevalence (26.1%; 157/600), fleas (37.8%; 227/600), as compared to summer season and spring. Though, summer season was found to be unfavourable for the increase of almost all these insects. Comparative results of blood profile revealed significant difference (P&lt;0.05) between non-infested and infested dogs, in the sort of lower value of infested/infected animals. To control the prevelance and ultimate effect of wingless insects on dog population applicable a well planned and control startegies as well as extension facilities should be arranged. Pet owners should be provided awareness about the significance of controlling the wingless insects to keep the pets and owner healthy.