The PfRCR complex bridges malaria parasite and erythrocyte during invasion.

The symptoms of malaria occur during the blood stage of infection, when parasites invade and replicate within human erythrocytes. The PfPCRCR complex1, containing PfRH5 (refs. 2,3), PfCyRPA, PfRIPR, PfCSS and PfPTRAMP, is essential for erythrocyte invasion by the deadliest human malaria parasite, Plasmodium falciparum. Invasion can be prevented by antibodies3-6 or nanobodies1 against each of these conserved proteins, making them the leading blood-stage malaria vaccine candidates. However, little is known about how PfPCRCR functions during invasion. Here we present the structure of the PfRCR complex7,8, containing PfRH5, PfCyRPA and PfRIPR, determined by cryogenic-electron microscopy. We test the hypothesis that PfRH5 opens to insert into the membrane9, instead showing that a rigid, disulfide-locked PfRH5 can mediate efficient erythrocyte invasion. We show, through modelling and an erythrocyte-binding assay, that PfCyRPA-binding antibodies5 neutralize invasion through a steric mechanism. We determine the structure of PfRIPR, showing that it consists of an ordered, multidomain core flexibly linked to an elongated tail. We also show that the elongated tail of PfRIPR, which is the target of growth-neutralizing antibodies6, binds to the PfCSS-PfPTRAMP complex on the parasite membrane. A modular PfRIPR is therefore linked to the merozoite membrane through an elongated tail, and its structured core presents PfCyRPA and PfRH5 to interact with erythrocyte receptors. This provides fresh insight into the molecular mechanism of erythrocyte invasion and opens the way to new approaches in rational vaccine design.

The gut parasite Nosema ceranae impairs olfactory learning in bumblebees.

Pollinators are exposed to numerous parasites and pathogens when foraging on flowers. These biological stressors may affect critical cognitive abilities required for foraging. Here, we tested whether exposure to Nosema ceranae, one of the most widespread parasites of honey bees also found in wild pollinators, impacts cognition in bumblebees. We investigated different forms of olfactory learning and memory using conditioning of the proboscis extension reflex. Seven days after being exposed to parasite spores, bumblebees showed lower performance in absolute, differential and reversal learning than controls. The consistent observations across different types of olfactory learning indicate a general negative effect of N. ceranae exposure that did not specifically target particular brain areas or neural processes. We discuss the potential mechanisms by which N. ceranae impairs bumblebee cognition and the broader consequences for populations of pollinators.

Perfil epidemiológico das enteroparasitoses em pré-escolares e escolares da rede municipal de ensino de Sinop - MT / Epidemiological profile of endoparasitoses in preschoolers and school children of the school district of Sinop - state of Mato Grosso

ntrodução: As enteroparasitoses são causadas por protozoários e helmintos e representam um importante proble-ma de saúde pública. As crianças em idade pré-escolar e escolar apresentam maior vulnerabilidade à contaminação por enteroparasitas pelo fato de estarem mais expostas a fatores de risco, tais como hábitos precários de higiene e aglomeração em locais fechados, e por não apresentarem o sistema imunológico totalmente desenvolvido. Os para-sitas mais comumente encontrados nessa faixa etária compreendem Giardia lamblia, Ascaris lumbricoides, Trichuris trichiura e ancilostomídeos. Objetivos: Avaliar a prevalência de enteroparasitos em crianças pré-escolares e escola-res e em caixas de areia de instituições públicas de ensino no município de Sinop-MT. Métodos: O estudo realizado foi transversal, quantitativo com delineamento experimental. Foi realizado no período de julho de 2015 a setembro de 2016. Foram avaliadas crianças pré-escolares e escolares de 3 a 12 anos escolhidas por amostragem de conveniência de quatro instituições da rede municipal de ensino localizadas na região central de Sinop ­ MT e sete afastadas do centro da cidade e que atendem novos bairros e a zona rural. As amostras de fezes foram coletadas pelos responsá-veis das crianças que encaminharam para as instituições de ensino e, posteriormente, foram transportadas ao labo-ratório para realização do exame parasitológico. As amostras de areia foram coletadas a partir de caixas das áreas de recreações de todas as instituições de ensino, sendo coletada 100 gramas de areia da raspagem superficial e pro-funda dos quatro quadrantes e do centro, totalizando 10 amostras/caixa. Os métodos parasitológicos utilizados para análises das amostras de fezes e areia foram Hoffmann, migração ativa, centrífugo-flutuação espontânea por Faust e flutuação espontânea por Willis. Resultados: Foram avaliadas 646 amostras de fezes de crianças pré-escolares e escolares de 3 a 12 anos, apresentando 21,05% de positividade para parasitos intestinais. Giardia lamblia apresentou maior prevalência, seguida de Entamoeba coli, Endolimax nana,Ascaris lumbricoides, Enterobius vermicularis, Hy-menolepis nana, ancilostomídeo e Entamoeba hartmanni. As 80 amostras de areia das caixas das áreas de recreação infantil avaliadas, apresentaram 100% de positividade para G. lamblia, seguida de 66,66% para Toxocara sp. nas areias das áreas centrais e 100% nas periféricas, 66,66% para Toxoplasma gondii nas centrais e 80% nas periféricas, 33,33% para A. lumbricoides nas centrais e 60% nas periféricas e 33,33% de Strongyloides stercoralis somente nas areias das áreas centrais. Conclusão: A faixa etária mais acometida foi verificada entre as crianças de 6 a 12 anos e pode estar relacionada aos precários hábitos de higiene e assim, maior risco de contaminação. Pode-se concluir que os resultados estão de acordo com a maioria dos estudos epidemiológicos realizados no Brasil, demonstrando elevada prevalência de enteroparasitoses em crianças em idade escolar (AU)

Introduction: Protozoa and helminths cause enteroparasitoses, which constitute an important public health issue. Preschoolers and school children, who do not have a fully developed immune system, are more vulnerable to con-tamination by intestinal parasites because they are more exposed to risk factors, such as poor hygiene habits and crowding in closed places. The most common parasites affecting this age group include Giardia lamblia, Ascaris lumbricoides, Trichuris trichiura, and hookworms. Objectives: To evaluate the prevalence of intestinal parasites in preschoolers, school children, and sandboxes of government schools in the city of Sinop ­ state of Mato Gros-so (MT). Methods: This cross-sectional, quantitative study with an experimental design was carried out from July 2015 to September 2016 and included preschoolers and school children aged 3 to 12 years, chosen by convenience sampling from government schools in the school district of the city of Sinop ­ MT; four schools were in the central region of Sinop, whereas seven schools, attended by children living in the suburban and rural areas, were far from the city center. Fecal samples were collected by the children's family and sent to the schools, from where they were transported to the laboratory for parasitological examination. Sand samples were collected from sandboxes in the play areas of the schools. More specifically,100 g of sand was collected by scraping one of the four quadrants or the center of the sandbox surface or deeper into the sandbox, totaling 10 samples/box. The parasitological methods spontaneous sedimentation described by Hoffmann, active migration described by Rugai, centrifugal-spontaneous flotation described by Faust, and spontaneous flotation described by Willis were used to analyze the fecal and sand samples. Results: A total of 646 fecal samples obtained from preschoolers and school children aged 3 to 12 years were evaluated; 21.05% of the samples tested positive for intestinal parasites. As for the sand samples, 100% tested positive for intestinal parasites. In all the fecal and sand samples that tested positive for intestinal parasites, G. lamblia predominated, followed by Toxacara sp, Toxoplasma gondii, A. lumbricoides, Enterobius vermicularis, Hymenolepis nana, Strongyloides stercoralis, hookworm, Entamoeba coli, Endolimax nana, and Entamoeba hart-manni, commensal amoebae of the large intestine, were also identified. Conclusion: Children aged 6 to 12 years were the most affected by enteroparasitoses. This may be related to poor hygiene habits, which puts these children at greater risk of contamination. The results agree with most epidemiological studies conducted in Brazil and show a high prevalence of enteroparasitoses in children (AU)

Pantothenate biosynthesis is critical for chronic infection by the neurotropic parasite Toxoplasma gondii.

Coenzyme A (CoA) is an essential molecule acting in metabolism, post-translational modification, and regulation of gene expression. While all organisms synthesize CoA, many, including humans, are unable to produce its precursor, pantothenate. Intriguingly, like most plants, fungi and bacteria, parasites of the coccidian subgroup of Apicomplexa, including the human pathogen Toxoplasma gondii, possess all the enzymes required for de novo synthesis of pantothenate. Here, the importance of CoA and pantothenate biosynthesis for the acute and chronic stages of T. gondii infection is dissected through genetic, biochemical and metabolomic approaches, revealing that CoA synthesis is essential for T. gondii tachyzoites, due to the parasite's inability to salvage CoA or intermediates of the pathway. In contrast, pantothenate synthesis is only partially active in T. gondii tachyzoites, making the parasite reliant on its uptake. However, pantothenate synthesis is crucial for the establishment of chronic infection, offering a promising target for intervention against the persistent stage of T. gondii.

Presence and significance of intestinal unicellular parasites in a morbidly obese population.

BACKGROUND: Obesity is a chronic disease whose pathogenesis has been related to changes in the intestinal microbiota. Yet, the role of protozoa and other unicellular eukaryotic parasites in this microenvironment is still largely unknown. Their presence within the gut ecosystem in obese subjects warrants further study, as well as their influence on the host metabolism and comorbidities. METHODS: Herein, a single center, cross-sectional study of 104 obese individuals was performed to assess the presence of six intestinal unicellular parasites in stool using a commercially available kit, and to evaluate its relationship with the presence of abdominal symptoms, metabolic comorbidities, variations in body composition and nutritional deficiencies. RESULTS: The overall parasitic colonization rate was 51%, with Blastocystis sp., identified as the most frequent (44.2%), followed by Dientamoeba fragilis (11.5%) and Giardia intestinalis (8.7%), and significantly related to the consumption of ecological fruits and vegetables. Contrary to what previous studies pointed out, colonization with parasites species was significantly associated with fewer abdominal symptoms and depositions per day. The presence of parasites did not correlate with any nutritional deficiencies nor differences in body composition, while it did with significant lower HOMA-IR levels and a lower trend towards metabolic syndrome. CONCLUSION: Obese subjects frequently harbor unicellular enteric parasites, apparently without clinical nor nutritional harm. This evidence suggests that carrying these microorganisms, from an endocrinological perspective, has a beneficial effect, especially on insulin resistance and possibly on the development of related comorbidities.

Prevalence of intestinal parasitic diseases in school children of rural areas of district Lower Dir, Pakistan / Prevalência de doenças parasitárias intestinais em escolares de áreas rurais do distrito de Lower Dir, Paquistão

Present study was conducted among school children to recognize the prevalence of IPIs in rural communities of district Dir Lower, Pakistan. A sum of 324 samples of stool were collected (210 boys and 114 girls). Used direct smear method and formol ether sedimentation concentration technique for processing the samples. The result shows that 82% (n=266) were found infected comprised 64.8% male and 35.1% females. Children of the age group 10 to 12 years were found extremely infected 94.2% while 4-6 year age group were having minimum ratio of infection 72%. Current study shows mono parasitism in 50.6% of the students while 22.2% were infected with 2 species and 7.40% were infected with three species of parasites. Seven species of intestinal parasites were reported include Ascaris lumbricoid in male (n=122) 58.0% and in female (n=65) 57.0% followed by Hook worm (n=88) 41.9% and (n=44) 38.5%; Tania saginata (n=44) 20.9% and (n=24) 21.0%; Entrobius vermicularis (n=32) 15.2% and (n=16) 14.0%; Trichuris trichura (n=25) 11.9% and (n=22) 19.2%; Hymenolepis nana (n=24) 11.4% and (n=18) 15.7% and Entameoba histolytica (n=16) 7.61% and (n=14) 12.2% in male and females respectively. The study indicates that most occurring intestinal parasite in the current study were Ascaris lumbricoides 58.0% (n=122) followed by hookworms 41.9% (n=88). Male students were more infected than females in the present study.

O presente estudo foi conduzido entre crianças em idade escolar para reconhecer a prevalência de IPIs em comunidades rurais do distrito de Dir Lower, Paquistão. Foram coletadas 324 amostras de fezes (210 meninos e 114 meninas). Método de esfregaço direto usado e técnica de concentração de sedimentação de formol éter para processar as amostras. O resultado mostra que 82% (n = 266) dos infectados eram 64,8% do sexo masculino e 35,1% do feminino. Crianças da faixa etária de 10 a 12 anos foram encontradas extremamente infectadas 94,2%, enquanto a faixa etária de 4 a 6 anos apresentava proporção mínima de infecção de 72%. O estudo atual mostra monoparasitismo em 50,6% dos alunos, enquanto 22,2% estavam infectados com 2 espécies e 7,40% estavam infectados com três espécies de parasitas. Sete espécies de parasitas intestinais foram relatadas incluindo Ascaris lumbricoid em machos (n = 122) 58,0% e em fêmeas (n = 65) 57,0% seguido por anzol (n = 88) 41,9% e (n = 44) 38,5%; Tania saginata (n = 44) 20,9% e (n = 24) 21,0%; Entrobius vermicularis (n = 32) 15,2% e (n = 16) 14,0%; Trichuris trichura (n = 25) 11,9% e (n = 22) 19,2%; Hymenolepis nana (n = 24) 11,4% e (n = 18) 15,7% e Entameoba histolytica (n = 16) 7,61% e (n = 14) 12,2% em homens e mulheres, respectivamente. O estudo indica que os parasitas intestinais que mais ocorreram no presente estudo foram Ascaris lumbricoides 58,0% (n = 122), seguidos por ancilóstomos 41,9% (n = 88). Estudantes do sexo masculino foram mais infectados do que do sexo feminino no presente estudo.

Prevalence of Intestinal Parasites and Schistosoma mansoni and Associated Factors among Fishermen at Lake Tana, Northwest Ethiopia.

BACKGROUND: Intestinal parasites and Schistosoma mansoni infections adversely affect the health of humans in the world especially in sub-Saharan African countries including Ethiopia. Fishermen who spend most of their time in water bodies are supposed to be at high risk of schistosomiasis and other water-born parasites. However, the magnitude of these parasitic infections and their determinant factors are not well addressed. METHODS: A cross-sectional study was conducted at Lake Tana among 388 fishermen from March to May 2021. Questionnaire data was collected through face to face interview. Stool sample from each participant was processed by the Kato-Katz and spontaneous tube sedimentation techniques. Data were analyzed using SPSS version 26. RESULTS: One hundred sixty four (42.3%) and 88 (22.7%) participants were infected by intestinal parasites and Schistosoma mansoni, respectively. One hundred twenty two (31.4%) and 42 (10.8%) participants were infected by soil-transmitted helminths and intestinal protozoa, respectively. Attending only primary school (AOR = 2.02, p = 0.014) or being illiterate (AOR = 2.54, p = 0.004) and not washing hands before meal (AOR = 2.23, p = 0.007) were significantly associated with intestinal parasitic infections. Illiterate educational status (AOR = 2.37, p = 0.022), fishing by bargee (AOR = 2.43, p = 0.005), fishing ≥4 days per week (AOR = 2.27, p = 0.029), swimming habit (AOR = 3.03, p = 0.030), and participation in irrigation (AOR = 3.09, p ≤ 0.001) predispose fishermen to S. mansoni infection. CONCLUSION: Intestinal parasites and S. mansoni infections are highly prevalent among fishermen at Lake Tana basin. Low education level and frequent water contact predispose fishermen for intestinal parasites and S. mansoni. Therefore, health education to fishermen on intestinal parasites and S. mansoni infection and regular deworming should be advocated.

Optimal immune specificity at the intersection of host life history and parasite epidemiology.

Hosts diverge widely in how, and how well, they defend themselves against infection and immunopathology. Why are hosts so heterogeneous? Both epidemiology and life history are commonly hypothesized to influence host immune strategy, but the relationship between immune strategy and each factor has commonly been investigated in isolation. Here, we show that interactions between life history and epidemiology are crucial for determining optimal immune specificity and sensitivity. We propose a demographically-structured population dynamics model, in which we explore sensitivity and specificity of immune responses when epidemiological risks vary with age. We find that variation in life history traits associated with both reproduction and longevity alters optimal immune strategies-but the magnitude and sometimes even direction of these effects depends on how epidemiological risks vary across life. An especially compelling example that explains previously-puzzling empirical observations is that depending on whether infection risk declines or rises at reproductive maturity, later reproductive maturity can select for either greater or lower immune specificity, potentially illustrating why studies of lifespan and immune variation across taxa have been inconclusive. Thus, the sign of selection on the life history-immune specificity relationship can be reversed in different epidemiological contexts. Drawing on published life history data from a variety of chordate taxa, we generate testable predictions for this facet of the optimal immune strategy. Our results shed light on the causes of the heterogeneity found in immune defenses both within and among species and the ultimate variability of the relationship between life history and immune specificity.

The hump-shaped effect of plant functional diversity on the biological control of a multi-species pest community.

Plant taxonomic and functional diversity promotes interactions at higher trophic levels, but the contribution of functional diversity effects to multitrophic interactions and ecosystem functioning remains unclear. We investigated this relationship in a factorial field experiment comparing the effect of contrasting plant communities on parasitism rates in five herbivore species. We used a mechanistic trait-matching approach between plant and parasitoids to determine the amount of nectar available and accessible to parasitoids. This trait-matching approach best explained the rates of parasitism of each herbivorous species, confirming the predominant role of mass-ratio effects. We found evidence for an effect of functional diversity only in analyses considering the ability of plant communities to support the parasitism of all herbivores simultaneously. Multi-species parasitism was maximal at intermediate levels of functional diversity. Plant specific richness had a negligible influence relative to functional metrics. Plant communities providing large amounts of accessible nectar and with intermediate levels of functional diversity were found to be the most likely to enhance the conservation biological control of diverse crop herbivores.

Parasite Survival and Disease Persistence in Cystic Fibrosis, Schistosomiasis and Pathogenic Bacterial Diseases: A Role for Universal Stress Proteins?

Universal stress proteins (USPs) were originally discovered in Escherichia coli over two decades ago and since then their presence has been detected in various organisms that include plants, archaea, metazoans, and bacteria. As their name suggests, they function in a series of various cellular responses in both abiotic and biotic stressful conditions such as oxidative stress, exposure to DNA damaging agents, nutrient starvation, high temperature and acidic stress, among others. Although a highly conserved group of proteins, the molecular and biochemical aspects of their functions are largely evasive. This is concerning, as it was observed that USPs act as essential contributors to the survival/persistence of various infectious pathogens. Their ubiquitous nature in various organisms, as well as their augmentation during conditions of stress, is a clear indication of their direct or indirect importance in providing resilience against such conditions. This paper seeks to clarify what has already been reported in the literature on the proposed mechanism of action of USPs in pathogenic organisms.

Relationship among bats, parasitic bat flies, and associated pathogens in Korea.

BACKGROUND: Bats are hosts for many ectoparasites and act as reservoirs for several infectious agents, some of which exhibit zoonotic potential. Here, species of bats and bat flies were identified and screened for microorganisms that could be mediated by bat flies. METHODS: Bat species were identified on the basis of their morphological characteristics. Bat flies associated with bat species were initially morphologically identified and further identified at the genus level by analyzing the cytochrome c oxidase subunit I gene. Different vector-borne pathogens and endosymbionts were screened using PCR to assess all possible relationships among bats, parasitic bat flies, and their associated organisms. RESULTS: Seventy-four bat flies were collected from 198 bats; 66 of these belonged to Nycteribiidae and eight to Streblidae families. All Streblidae bat flies were hosted by Rhinolophus ferrumequinum, known as the most common Korean bat. Among the 74 tested bat flies, PCR and nucleotide sequencing data showed that 35 (47.3%) and 20 (27.0%) carried Wolbachia and Bartonella bacteria, respectively, whereas tests for Anaplasma, Borrelia, Hepatozoon, Babesia, Theileria, and Coxiella were negative. Phylogenetic analysis revealed that Wolbachia endosymbionts belonged to two different supergroups, A and F. One sequence of Bartonella was identical to that of Bartonella isolated from Taiwanese bats. CONCLUSIONS: The vectorial role of bat flies should be checked by testing the same pathogen and bacterial organisms by collecting blood from host bats. This study is of great interest in the fields of disease ecology and public health owing to the bats' potential to transmit pathogens to humans and/or livestock.

Evolution of Cellular Immunity Effector Cells; Perspective on Cytotoxic and Phagocytic Cellular Lineages.

The immune system has evolved to protect organisms from infections caused by bacteria, viruses, and parasitic pathogens. In addition, it provides regenerative capacities, tissue maintenance, and self/non-self recognition of foreign tissues. Phagocytosis and cytotoxicity are two prominent cellular immune activities positioned at the base of immune effector function in mammals. Although these immune mechanisms have diversified into a wide heterogeneous repertoire of effector cells, it appears that they share some common cellular and molecular features in all animals, but also some interesting convergent mechanisms. In this review, we will explore the current knowledge about the evolution of phagocytic and cytotoxic immune lineages against pathogens, in the clearance of damaged cells, for regeneration, for histocompatibility recognition, and in killing virally infected cells. To this end, we give different immune examples of multicellular organism models, ranging from the roots of bilateral organisms to chordate invertebrates, comparing to vertebrates' lineages. In this review, we compare cellular lineage homologies at the cellular and molecular levels. We aim to highlight and discuss the diverse function plasticity within the evolved immune effector cells, and even suggest the costs and benefits that it may imply for organisms with the meaning of greater defense against pathogens but less ability to regenerate damaged tissues and organs.

Seropositivity to canine tick-borne pathogens in a population of sick dogs in Italy.

BACKGROUND: Canine vector-borne diseases (CVBDs) associated to ticks are among the most important health issues affecting dogs. In Italy, Ehrlichia canis, Anaplasma spp., Rickettsia conorii and Borrelia burgdorferi (s.l.) have been studied in both healthy canine populations and those clinically ill with suspected CVBDs. However, little information is currently available on the overall prevalence and distribution of these pathogens in the country. The aim of this study was to assess the prevalence and distribution of tick-borne pathogens (TBPs) in clinically suspect dogs from three Italian macro areas during a 15-year period (2006-2020). METHODS: A large dataset (n = 21,992) of serological test results for selected TBPs in three macro areas in Italy was analysed using a Chi-square test to evaluate the associations between the categorical factors (i.e. macro area, region, year, sex and age) and a standard logistic regression model (significance set at P = 0.05). Serological data were presented as annual and cumulative prevalence, and distribution maps of cumulative positive cases for TBPs were generated. RESULTS: Of the tested serum samples, 86.9% originated from northern (43.9%) and central (43%) Italy. The majority of the tests was requested for the diagnosis of E. canis (47%; n = 10,334), followed by Rickettsia spp. (35.1%; n = 7725), B. burgdorferi (s.l.) (11.6%; n = 2560) and Anaplasma spp. (6.2%; n = 1373). The highest serological exposure was recorded for B. burgdorferi (s.l.) (83.5%), followed by Rickettsia spp. (64.9%), Anaplasma spp. (39.8%) and E. canis (28.7%). The highest number of cumulative cases of Borrelia burgdorferi (s.l.) was recorded in samples from Tuscany, central Italy. Rickettsia spp. was more prevalent in the south and on the islands, particularly in dogs on Sicily older than 6 years, whereas Anaplasma spp. was more prevalent in the north and E. canis more prevalent in the south and on the islands. CONCLUSIONS: The results of this study highlight the high seroprevalence and wide distribution of the four TBPs in dogs with clinically suspected CVBDs from the studied regions of Italy. The very high seroprevalence of B. burgdorferi (s.l.) exemplifies a limitation of this study, given the use of clinically suspect dogs and the possibility of cross-reactions when using serological tests. The present research provides updated and illustrative information on the seroprevalence and distribution of four key TBPs, and advocates for integrative control strategies for their prevention.

Lipid droplets and the host-pathogen dynamic: FATal attraction?

In the ongoing conflict between eukaryotic cells and pathogens, lipid droplets (LDs) emerge as a choke point in the battle for nutrients. While many pathogens seek the lipids stored in LDs to fuel an expensive lifestyle, innate immunity rewires lipid metabolism and weaponizes LDs to defend cells and animals. Viruses, bacteria, and parasites directly and remotely manipulate LDs to obtain substrates for metabolic energy, replication compartments, assembly platforms, membrane blocks, and tools for host colonization and/or evasion such as anti-inflammatory mediators, lipoviroparticles, and even exosomes. Host LDs counterattack such advances by synthesizing bioactive lipids and toxic nucleotides, organizing immune signaling platforms, and recruiting a plethora of antimicrobial proteins to provide a front-line defense against the invader. Here, we review the current state of this conflict. We will discuss why, when, and how LDs efficiently coordinate and precisely execute a plethora of immune defenses. In the age of antimicrobial resistance and viral pandemics, understanding innate immune strategies developed by eukaryotic cells to fight and defeat dangerous microorganisms may inform future anti-infective strategies.

Do blood parasites increase immature erythrocytes and mitosis in amphibians? / ¿Causan los parásitos sanguíneos un aumento en los eritrocitos inmaduros y la mitosis en los anfibios?

Abstract Introduction: In amphibians, blood may act as a hematopoietic tissue. However, the knowledge concerning hematological features is scarce, there is not much information that allows an analysis about the possible explanations of this physiological feature. Objective: This study aimed to evaluate the relationship between immature red blood cells (RBCs) mitosis and the presence of blood parasites in amphibians. Methods: We sampled 116 amphibians (31 species) in six Colombian localities. Blood was taken by cardiac puncture or maxillary vein puncture. Smears were prepared, fixed, and Giemsa stained for microscopical analysis. The variables analyzed were the percentage of immature RBCs, mitotic cells in peripheral blood, and blood parasite infection. Data were analyzed using Wilcoxon's rank test and exact Fisher statistical tests. Results: Sixty-two individuals showed mitosis in peripheral blood, and these mitotic RBCs shared morphological features with immature RBCs. Overall, parasite prevalence was 30.1 %, distributed as follows: Trypanosoma (24.1 %), Hepatozoon-like (6 %), Dactylosoma (4.3 %), Karyolysus-like (0.9 %), and Filarioidea (2.6 %). A positive association between the percentage of immature RBCs and the presence of mitotic RBCs was found, and also between the blood parasite infection and the percentage of immature RBCs. Conclusions: In this study, we found that the presence of blood parasites, immature RBCs, and RBCs mitosis are frequent events in amphibians' peripheral blood, and our analysis suggests an association between those features. Thus, the release of immature RBCs and the mitosis of those cells in peripheral blood may be a physiological response to blood parasite infection. Further studies characterizing hematology in amphibians and wildlife, in general, are desirable.

Resumen Introducción: En anfibios, la sangre puede actuar como un tejido hematopoyético. Sin embargo, el conocimiento acerca de las características hematológicas es escaso y no hay información que permita un análisis acerca de las posibles explicaciones a este rasgo fisiológico. Objetivo: La intención de este estudio fue evaluar la relación entre la presencia de eritroblastos, mitosis de glóbulos rojos (GRs) y la infección por hemoparásito en sangre periférica de anfibios. Métodos: Se muestrearon 116 anfibios (31 especies) en seis localidades de Colombia. Se tomaron muestras de sangre mediante punción cardiaca o punción a la vena maxilar. Se prepararon extendidos sanguíneos, se fijaron y tiñeron con Giemsa para su posterior análisis por microscopía. Se analizaron variables como porcentaje de GRs inmaduros, células mitóticas en sangre periférica e infección por hemoparásitos. Los datos fueron analizados mediante el test de rango de Willcoxon y el test exacto de Fisher. Resultados: sesenta y dos individuos evidenciaron mitosis en sangre periférica y dichas mitosis compartían características morfológicas con GRs inmaduros. La prevalencia general de parásitos fue del 30.1 %, distribuido de la siguiente forma: Trypanosoma (24.1 %), Hepatozoon-like (6 %), Dactylosoma (4.3 %), Karyolysus-like (0.9 %), y Filarioidea (2. 6 %). Hay una asociación positiva entre el porcentaje de GRs inmaduros y la presencia de células mitóticas, también se encontró una relación entre la infección por hemoparásitos y el porcentaje de GRs inmaduros. Conclusiones: En este estudio encontramos que la presencia de parásitos sanguíneos, GRs inmaduros y mitosis de GRs son eventos frecuentes en sangre periférica de anfibios, y nuestros resultados sugieren una asociación entre dichas características. Por tanto, la liberación de GRs inmaduros y la mitosis de estas células en sangre periférica podría ser una respuesta fisiológica a infecciones parasitarias. Posteriores estudios que caractericen la hematología en anfibios y en vida silvestre en general, son deseables.

Endoparasite prevalence and infection risk factors among cats in an animal shelter in Estonia.

Cats are important hosts for different zoonotic parasites that can be hazardous to human health. To date, few studies have attempted to identify the factors affecting parasitic infections in shelter animals. This study aims to analyse the presence of endoparasites in shelter cats in Tartu, Estonia, and identify factors affecting endoparasite prevalence and intensity. The risk factors considered were age, location (urban vs rural cats) and time spent in shelter. In total, 290 faecal samples were collected from cats at an animal shelter in 2015-2016 and investigated for endoparasites using the concentration flotation technique. In total, 138 shelter cats (47.6%) were infected with endoparasites and their overall prevalence was: Toxocara cati (36.6%), Cystoisospora spp. (12.4%), Taeniidae gen. sp. (4.1%), Toxoplasma gondii/Hammondia hammondi (3.4%), Eucoleus aerophilus (2.1%), Cryptosporidium spp. (2.1%), Ancylostoma sp. (0.7%) and Giardia sp. (0.7%). Coinfections occurred in 38 cats (13.1%) most frequently of T. cati and Cystoisospora spp. (4.5%), Cystoisospora spp. and T. gondii/H. hammondi (2.1%). Where species identification of cestode and nematode samples was not possible according to morphology, genetic analysis of the mitochondrial cox1 gene was carried out. DNA was successfully analysed for 6 out of 13 samples that required genetic identification, revealing Ancylostoma tubaeforme in one nematode sample and Hydatigera taeniaeformis in five cestode samples. Cats from rural areas had significantly higher endoparasite prevalence than cats from urban areas. Helminth prevalence decreased to some extent due to anthelmintic treatment in cats available for adoption (held ≥15 days in the shelter), whereas the prevalence of infection with protists increased significantly in these animals. It is important to note that the analysis revealed lower infection intensity for quarantine cats (held 1-14 days in the shelter) compared with cats available for adoption. The relatively high prevalence of endoparasites (including zoonotic) in shelter cats ready for adoption suggests that current anthelminthic procedures require improvements.

Parasites and RNA viruses in wild and laboratory reared bumble bees Bombus pauloensis (Hymenoptera: Apidae) from Uruguay.

Bumble bees (Bombus spp.) are important pollinators insects involved in the maintenance of natural ecosystems and food production. Bombus pauloensis is a widely distributed species in South America, that recently began to be managed and commercialized in this region. The movement of colonies within or between countries may favor the dissemination of parasites and pathogens, putting into risk while populations of B. pauloensis and other native species. In this study, wild B. pauloensis queens and workers, and laboratory reared workers were screened for the presence of phoretic mites, internal parasites (microsporidia, protists, nematodes and parasitoids) and RNA viruses (Black queen cell virus (BQCV), Deformed wing virus (DWV), Acute paralysis virus (ABCV) and Sacbrood virus (SBV)). Bumble bee queens showed the highest number of mite species, and it was the only group where Conopidae and S. bombi were detected. In the case of microsporidia, a higher prevalence of N. ceranae was detected in field workers. Finally, the bumble bees presented the four RNA viruses studied for A. mellifera, in proportions similar to those previously reported in this species. Those results highlight the risks of spillover among the different species of pollinators.

Potential zoonotic pathogens hosted by endangered bonobos.

Few publications, often limited to one specific pathogen, have studied bonobos (Pan paniscus), our closest living relatives, as possible reservoirs of certain human infectious agents. Here, 91 stool samples from semicaptive bonobos and bonobos reintroduced in the wild, in the Democratic Republic of the Congo, were screened for different infectious agents: viruses, bacteria and parasites. We showed the presence of potentially zoonotic viral, bacterial or parasitic agents in stool samples, sometimes coinfecting the same individuals. A high prevalence of Human mastadenoviruses (HAdV-C, HAdV-B, HAdV-E) was observed. Encephalomyocarditis viruses were identified in semicaptive bonobos, although identified genotypes were different from those identified in the previous fatal myocarditis epidemic at the same site in 2009. Non-pallidum Treponema spp. including symbiotic T. succinifaciens, T. berlinense and several potential new species with unknown pathogenicity were identified. We detected DNA of non-tuberculosis Mycobacterium spp., Acinetobacter spp., Salmonella spp. as well as pathogenic Leptospira interrogans. Zoonotic parasites such as Taenia solium and Strongyloides stercoralis were predominantly present in wild bonobos, while Giardia lamblia was found only in bonobos in contact with humans, suggesting a possible exchange. One third of bonobos carried Oesophagostomum spp., particularly zoonotic O. stephanostomum and O. bifurcum-like species, as well as other uncharacterized Nematoda. Trypanosoma theileri has been identified in semicaptive bonobos. Pathogens typically known to be transmitted sexually were not identified. We present here the results of a reasonably-sized screening study detecting DNA/RNA sequence evidence of potentially pathogenic viruses and microorganisms in bonobo based on a noninvasive sampling method (feces) and focused PCR diagnostics.