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25 Apr 2023
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The distribution, phenology, host range and pathogen prevalence of Ixodes ricinus in France: a systematic map and narrative review

An extensive review of Ixodes ricinus in European France

Recommended by based on reviews by Ana Palomar and 1 anonymous reviewer

Ticks are obligate, bloodsucking, nonpermanent ectoparasitic arthropods. Among them, Ixodes ricinus is a classic example of an extreme generalist tick, presenting a highly permissive feeding behavior using different groups of vertebrates as hosts, such as mammalian (including humans), avian and reptilian species (Hoogstraal & Aeschlimann, 1982; Dantas-Torresa & Otranto, 2013). This ecological adaptation can account for the broad geographical distribution of I. ricinus populations, which extends from the western end of the European continent to the Ural Mountains in Russia, and from northern Norway to the Mediterranean basin, including the North African countries - Morocco, Algeria and Tunisia (https://ecdc.europa.eu/en/disease-vectors/surveillance-and-disease-data/tick-maps). The contact with different hosts also promotes the exposure/acquisition and transmission of various pathogenic agents (viruses, bacteriae, protists and nematodes) of veterinary and medical relevance (Aeschlimann et al., 1979). As one of the prime ticks found on humans, this species is implicated in diseases such as Lyme borreliosis, Spotted Fever Group rickettsiosis, Human Anaplasmosis, Human Babesiosis and Tick-borne Encephalitis (Velez et al., 2023). 

The climate change projections drawn for I. ricinus, in the scenario of global warming, point for the expansion/increase activity in both latitude and altitude (Medlock et al., 2013). The adequacy of vector modeling is relaying in the proper characterization of complex biological systems. Thus, it is essential to increase knowledge on I. ricinus, focusing on aspects such as genetic background, ecology and eco-epidemiology on a microscale but also at a country and region level, due to possible local adaptations of tick populations and genetic drift. 

In the present systematic revision, Perez et al. (2023) combine old and recently published data (mostly up to 2020) regarding I. ricinus distribution, phenology, host range and pathogen association in continental France and Corsica Island. Based on a keyword search of peer-reviewed papers on seven databases, as well as other sources of grey literature (mostly, thesis), the authors have synthesized information on: 1) Host parasitism to detect potential differences in host use comparing to other areas in Europe; 2) The spatiotemporal distribution of I. ricinus, to identify possible geographic trends in tick density, variation in activity patterns and the influence of environmental factors; 3) Tick-borne pathogens detected in this species, to better assess their spatial distribution and variation in exposure risk. 

As pointed out by both reviewers, this work clearly summarizes the information regarding I. ricinus and associated microorganisms from European France. This review also identifies remaining knowledge gaps, providing a comparable basis to orient future research. This is why I chose to recommend Perez et al (2023)'s preprint for Peer Community Infections. 

REFERENCES

Aeschlimann, A., Burgdorfer, W., Matile, H., Peter, O., Wyler, R. (1979) Aspects nouveaux du rôle de vecteur joué par Ixodes ricinus L. en Suisse. Acta Tropica, 36, 181-191.

Dantas-Torresa, F., Otranto, D. (2013) Seasonal dynamics of Ixodes ricinus on ground level and higher vegetation in a preserved wooded area in southern Europe. Veterinary Parasitology, 192, 253- 258.
https://doi.org/10.1016/j.vetpar.2012.09.034

Hoogstraal, H., Aeschlimann, A. (1982) Tick-host specificity. Mitteilungen der Schweizerischen Entomologischen Gesellschaft, 55, 5-32.

Medlock, J.M., Hansford, K.M., Bormane, A., Derdakova, M., Estrada-Peña, A., George, J.C., Golovljova, I., Jaenson, T.G.T., Jensen, J.K., Jensen, P.M., Kazimirova, M., Oteo, J.A., Papa, A., Pfister, K., Plantard, O., Randolph, S.E., Rizzoli, A., Santos-Silva, M.M., Sprong, H., Vial, L., Hendrickx, G., Zeller, H., Van Bortel, W. (2013) Driving forces for changes in geographical distribution of Ixodes ricinus ticks in Europe. Parasites and Vectors, 6. https://doi.org/10.1186/1756-3305-6-1

Perez, G., Bournez, L., Boulanger, N., Fite, J., Livoreil, B., McCoy, K., Quillery, E., René-Martellet, M., Bonnet, S. (2023) The distribution, phenology, host range and pathogen prevalence of Ixodes ricinus in France: a systematic map and narrative review. bioRxiv, ver. 1 peer-reviewed and recommended by Peer Community in Infections. https://doi.org/10.1101/2023.04.18.537315

Velez, R., De Meeûs, T., Beati, L., Younsi, H., Zhioua, E., Antunes, S., Domingos, A., Ataíde Sampaio, D., Carpinteiro, D., Moerbeck, L., Estrada-Peña, A., Santos-Silva, M.M., Santos, A.S. (2023) Development and testing of microsatellite loci for the study of population genetics of Ixodes ricinus Linnaeus, 1758 and Ixodes inopinatus Estrada-Peña, Nava & Petney, 2014 (Acari: Ixodidae) in the western Mediterranean region. Acarologia, 63, 356-372. https://doi.org/10.24349/bvem-4h49

The distribution, phenology, host range and pathogen prevalence of *Ixodes ricinus* in France: a systematic map and narrative reviewGrégoire Perez, Laure Bournez, Nathalie Boulanger, Johanna Fite, Barbara Livoreil, Karen D. McCoy, Elsa Quillery, Magalie René-Martellet, and Sarah I. Bonnet<p style="text-align: justify;">The tick <em>Ixodes ricinus</em> is the most important vector species of infectious diseases in European France. Understanding its distribution, phenology, and host species use, along with the distribution and preva...Animal diseases, Behaviour of hosts, infectious agents, or vectors, Disease Ecology/Evolution, Ecohealth, Ecology of hosts, infectious agents, or vectors, Epidemiology, Geography of infectious diseases, Interactions between hosts and infectious ag...Ana Sofia Santos2022-12-06 14:52:44 View
28 Sep 2023
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Influence of endosymbionts on the reproductive fitness of the tick Ornithodoros moubata

The cost of endosymbionts on the reproductive fitness of the soft tick Ornithodoros moubata

Recommended by ORCID_LOGO based on reviews by Luciana Raggi Hoyos and Tuomas Aivelo ?

Ticks are amongst the most important pathogen vectors in medical and veterinary clinical settings worldwide (Dantas-Torres et al., 2012). Like other holobionts, ticks live in association with a diverse microbiota. It includes tick-borne pathogens (TBP) and other microorganisms that have a beneficial or detrimental effect on the physiology of the host and can also affect the transmission of TBP to animals or humans. In this microbiota, primary endosymbionts, which are obligatory and inheritable, play a role in tick reproduction, the host defense and adaptation to varying environmental conditions (Duron et al., 2018). However, the effect of the microbiota structure and of the endosymbionts on tick fitness and reproduction is not well known. The soft tick Ornithodoros moubata, a parasite known to transmit African swine fever virus (Vial, 2009), is known to host Francisella-like and Rickettsia endosymbionts (Duron et al., 2018). These endosymbionts carry genes involved in B vitamin synthesis which may be supplemented to the host (Bonnet & Pollet, 2021). 

Here, the authors investigated the role of endosymbionts on the reproductive fitness of Ornithodoros moubata by conducting two experiments (Taraveau et al., 2023). First, they tested the effect of antibiotic treatment of 366 first-stage nymphs on the main endosymbionts Francisella-like and Rickettsia, and measured the endosymbionts presence overtime by qPCR. Second, they surveyed the effect of antibiotic treatment with or without the addition of B vitamins on the survival and reproductive fitness of 132 females over 50 days. This second experiment intended to identify whether the endosymbionts have an effect on the host reproduction or on its nutrition. The supplementation of B vitamin did not have a drastic effect on tick fitness or reproductive traits. However, antibiotic treatments reduced the presence of endosymbionts while increasing tick survival, suggesting a potential cost of hosting endosymbionts on the tick fitness.

The authors did a lot of work to thoroughly follow the propositions from Dr Raggi, Dr Aivelo and myself to reconstruct and to revise the manuscript. I believe that the manuscript now reads very well and the answers to the reviews also add some value to the manuscript. As Dr Aivelo pointed out, “this study follows the traditional path of so-called population perturbation studies, where ecologists have administered antibiotics or antihelminths to different animals and seen how the community changes and what effects this has on the host fitness and survival”. As both reviewers stated, results from this study are valuable and provide important basic knowledge that will likely help conduct future experiments on tick microbiota. This recommendation is the result of the thorough reviewing work of Dr Aivelo and Dr Raggi which I warmly thank.
 
References

Bonnet, S. I., & Pollet, T. (2021). Update on the intricate tango between tick microbiomes and tick‐borne pathogens. Parasite Immunology, 43(5), e12813. https://doi.org/10.1111/pim.12813

Dantas-Torres, F., Chomel, B. B., & Otranto, D. (2012). Ticks and tick-borne diseases: A One Health perspective. Trends in Parasitology, 28(10), 437–446. https://doi.org/10.1016/j.pt.2012.07.003

Duron, O., Morel, O., Noël, V., Buysse, M., Binetruy, F., Lancelot, R., Loire, E., Ménard, C., Bouchez, O., Vavre, F., & Vial, L. (2018). Tick-Bacteria Mutualism Depends on B Vitamin Synthesis Pathways. Current Biology, 28(12), 1896-1902.e5. https://doi.org/10.1016/j.cub.2018.04.038

Taraveau, F., Pollet, T., Duhayon, M., Gardès, L., & Jourdan-Pineau, H. (2023). Influence of endosymbionts on the reproductive fitness of the tick Ornithodoros moubata. bioRxiv, ver.3, peer-reviewed and recommended by Peer Community in Infections. https://doi.org/10.1101/2023.05.09.539061

Vial, L. (2009). Biological and ecological characteristics of soft ticks (Ixodida: Argasidae) and their impact for predicting tick and associated disease distribution. Parasite, 16(3), 191–202. https://doi.org/10.1051/parasite/2009163191

Influence of endosymbionts on the reproductive fitness of the tick *Ornithodoros moubata*Taraveau Florian, Pollet Thomas, Duhayon Maxime, Gardès Laëtitia, Jourdan-Pineau Hélène<p style="text-align: justify;">Over the past decade, many studies have demonstrated the crucial role of the tick microbiome in tick biology. The soft tick <em>Ornithodoros moubata</em> is a hematophagous ectoparasite of <em>Suidae</em>, best know...Mutualistic symbionts, Parasites, Pathogenic/Symbiotic Bacteria, Physiology of hosts, infectious agents, or vectors, VectorsAngélique Gobet2023-05-25 19:00:33 View
28 Oct 2022
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Development of nine microsatellite loci for Trypanosoma lewisi, a potential human pathogen in Western Africa and South-East Asia, and preliminary population genetics analyses

Preliminary population genetic analysis of Trypanosoma lewisi

Recommended by based on reviews by Gabriele Schönian and 1 anonymous reviewer

Trypanosoma lewisi is an atypical trypanosome species. Transmitted by fleas, it has a high prevalence and worldwide distribution in small mammals, especially rats [1]. Although not typically thought to infect humans, there has been a number of reports of human infections by T. lewisi in Asia including a case of a fatal infection in an infant [2]. The fact that the parasite is resistant to lysis by normal human serum [3] suggests that many people, especially immunocompromised individuals, may be at risk from zoonotic infections by this pathogen, particularly in regions where there is close contact with T. lewisi-infected rat fleas. Indeed, it is also possible that cryptic T. lewisi infections exist but have hitherto gone undetected. Such asymptomatic infections have been detected for a number of parasitic infections including the related parasite T. b. gambiense [4]. 
 
Despite the fact that T. lewisi parasites pose a risk to human health, very little is known about their population structure, reproductive mode, population size or dispersal. In the article [5], Ségard et al. presented the first attempt at examining the population structure of the parasite. They developed microsatellite markers and used them to analyse a small set of samples from West Africa and Southeast Asia. Although the number of microsatellite markers is not very high and they encountered problems of PCR amplification especially of the southeast Asian samples, they did provide preliminary data that hints at a clonal population structure with rare recombination and suggests population subdivisions occurring at a scale that is equal, and probably smaller than a neighborhood of several houses with a short generation time. These are very interesting preliminary findings that will need to be validated using a larger cohort with more markers or by whole genome sequencing.
 

References


[1] Hoare CA (1972) The trypanosomes of mammals. A zoological monograph. The trypanosomes of mammals. A zoological monograph.

[2] Truc P, Büscher P, Cuny G, Gonzatti MI, Jannin J, Joshi P, Juyal P, Lun Z-R, Mattioli R, Pays E, Simarro PP, Teixeira MMG, Touratier L, Vincendeau P, Desquesnes M (2013) Atypical Human Infections by Animal Trypanosomes. PLOS Neglected Tropical Diseases, 7, e2256. https://doi.org/10.1371/journal.pntd.0002256

[3] Lun Z-R, Wen Y-Z, Uzureau P, Lecordier L, Lai D-H, Lan Y-G, Desquesnes M, Geng G-Q, Yang T-B, Zhou W-L, Jannin JG, Simarro PP, Truc P, Vincendeau P, Pays E (2015) Resistance to normal human serum reveals Trypanosoma lewisi as an underestimated human pathogen. Molecular and Biochemical Parasitology, 199, 58–61. https://doi.org/10.1016/j.molbiopara.2015.03.007

[4] Büscher P, Bart J-M, Boelaert M, Bucheton B, Cecchi G, Chitnis N, Courtin D, Figueiredo LM, Franco J-R, Grébaut P, Hasker E, Ilboudo H, Jamonneau V, Koffi M, Lejon V, MacLeod A, Masumu J, Matovu E, Mattioli R, Noyes H, Picado A, Rock KS, Rotureau B, Simo G, Thévenon S, Trindade S, Truc P, Reet NV (2018) Do Cryptic Reservoirs Threaten Gambiense-Sleeping Sickness Elimination? Trends in Parasitology, 34, 197–207. https://doi.org/10.1016/j.pt.2017.11.008

[5] Ségard A, Roméro A, Ravel S, Truc P, Gauthier D, Gauthier P, Dossou H-J, Sylvestre B, Houéménou G, Morand S, Chaisiri K, Noûs C, De Meeûs T (2022) Development of nine microsatellite loci for Trypanosoma lewisi, a potential human pathogen in Western Africa and South-East Asia, and preliminary population genetics analyses. Zenodo, 6460010, ver. 3 peer-reviewed and recommended by Peer Community in Infections. https://doi.org/10.5281/zenodo.6460010

Development of nine microsatellite loci for Trypanosoma lewisi, a potential human pathogen in Western Africa and South-East Asia, and preliminary population genetics analysesAdeline Ségard, Audrey Romero, Sophie Ravel, Philippe Truc, Gauthier Dobigny, Philippe Gauthier, Jonas Etougbetche, Henri-Joel Dossou, Sylvestre Badou, Gualbert Houéménou, Serge Morand, Kittipong Chaisiri, Camille Noûs, Thierry deMeeûs<p><em>Trypanosoma lewisi</em> belongs to the so-called atypical trypanosomes that occasionally affect humans. It shares the same hosts and flea vector of other medically relevant pathogenic agents as Yersinia pestis, the agent of plague. Increasi...Animal diseases, Disease Ecology/Evolution, Ecology of hosts, infectious agents, or vectors, Eukaryotic pathogens/symbionts, Evolution of hosts, infectious agents, or vectors, Microbiology of infections, Parasites, Population genetics of hosts, in...Annette MacLeod2022-04-21 17:04:37 View
14 Feb 2024
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A Bayesian analysis of birth pulse effects on the probability of detecting Ebola virus in fruit bats

Epidemiological modeling to optimize the detection of zoonotic viruses in wild (reservoir) species

Recommended by ORCID_LOGO based on reviews by Hetsron Legrace NYANDJO BAMEN and 1 anonymous reviewer

Various species of Ebolavirus have caused, and are still causing, zoonotic outbreaks and public health crises in Africa. Bats have long been hypothesized to be important reservoir populations for a series of viruses such as Hendra or Marburg viruses, the severe acute respiratory syndrome coronavirus (SARS-CoV, SARS-CoV-2) as well as Ebolaviruses [2, 3]. However the ecology of disease dynamics, disease transmission, and coevolution with their natural hosts of these viruses is still poorly understood, despite their importance for predicting novel outbreaks in human or livestock populations. The evidence that bats function as sylvatic reservoirs for Ebola viruses is yet only partial. Indeed, only few serological studies demonstrated the presence of Ebolavirus antibodies in young bats [4], albeit without providing positive controls of viral detection or identifying the viral species (via PCR). There is thus an unexplained discrepancy between serological data and viral detection [2, 4]. 

In this article, Pleydell et al. [1] use a modeling approach as well as published serological and age-structure (of the bat population) data to calibrate the model simulations. The study starts with the development of an age-structured epidemiological model which includes seasonal birth pulses and waning immunity, both generating pulses of Ebolavirus transmission within a colony of African straw-coloured fruit bats (Eidolon helvum). The epidemiological dynamics of such system of ordinary differential equations can generate annual outbreaks, skipped years or multi-annual cycles up to chaotic dynamics. Therefore, the calibration of the parameters, and the definition of biologically relevant priors, are key. To this aim, the serological data are obtained from a previous study in Cameroon [5], and the age structured of the bat population (birth and mortality) from a population study in Ghana [6]. These data are integrated into the Bayesian analysis and statistical framework to fit the model and generate predictions. In a nutshell, the authors show an overlap between the data and credibility intervals generated by the calibrated model, which thus explains well the seasonality of age-structure, namely changes in pup presence, number of lactating females, or proportion of juveniles in May. The authors can estimate that 76% of adults and 39% of young bats do survive each year, and infections are expected to last one and a half weeks. The epidemiological model predicts that annual birth pulses likely generate annual disease outbreaks, so that weeks 30 to 31 of each year, are predicted to be the best period to isolate the circulating Ebolavirus in this bat population. From the model predictions, the authors estimate the probability to have missed an infectious bat among all the samples tested by PCR being approximately of one per two thousands. The disease dynamics pattern observed in the serology data, and replicated by the model, is likely driven by seasonal pulses of young susceptible bats entering the population. This seasonal birth event increases the viral transmission, resulting in the observed peak of viral prevalence. With the inclusion of immunity waning and antibody persistence, the model results illuminate therefore why previous studies have detected only few positive cases by PCR tests, in contrast to the evidence from serological data. 

 This study provides a first proof of principle that epidemiological modeling, despite its many simplifying assumptions, can be applied to wild species reservoirs of zoonotic diseases in order to optimize the design of field studies to detect viruses. Furthermore, such models can contribute to assess the probability and timing of zoonotic outbreaks in human or livestock populations. This article illustrates one of the manifold applications of mathematical theory of disease epidemiology to optimize sampling of pathogens/parasites or vaccine development and release [7, 8]. The further coupling of such models with population genetics theory and statistical inference methods (using parasite genome data) increasingly provide insights into the adaptation and evolution of parasites to human, crops and livestock populations [9, 10].

 

References

[1] Pleydell D.R.J., Ndong Bass I., Mba Djondzo F.A., Djomsi D.M., Kouanfack C., Peeters M., and J. Cappelle. 2023. A Bayesian analysis of birth pulse effects on the probability of detecting Ebola virus in fruit bats. bioRxiv, ver. 3 peer reviewed and recommended by Peer Community In Infections. https://doi.org/10.1101/2023.08.10.552777

[2] Caron A., Bourgarel M., Cappelle J., Liégeois F., De Nys H.M., and F. Roger. 2018. Ebola virus maintenance: if not (only) bats, what else? Viruses 10, 549. https://doi.org/10.3390/v10100549

[3] Letko M., Seifert S.N., Olival K.J., Plowright R.K., and V.J. Munster. 2020. Bat-borne virus diversity, spillover and emergence. Nature Reviews Microbiology 18, 461–471. https://doi.org/10.1038/s41579-020-0394-z

[4] Leroy E.M., Kumulungui B., Pourrut X., Rouquet P., Hassanin A., Yaba P., Délicat A., Paweska J.T., Gonzalez J.P., and R. Swanepoel. 2005. Fruit bats as reservoirs of Ebola virus. Nature 438, 575–576. https://doi.org/10.1038/438575a

[5] Djomsi D.M. et al. 2022. Dynamics of antibodies to Ebolaviruses in an Eidolon helvum bat colony in Cameroon. Viruses 14, 560. https://doi.org/10.3390/v14030560

[6] Peel A.J. et al. 2016. Bat trait, genetic and pathogen data from large-scale investigations of African fruit bats Eidolon helvum. Scientific data 3, 1–11. https://doi.org/10.1038/sdata.2016.49

[7] Nyandjo Bamen H.L., Ntaganda J.M., Tellier A. and O. Menoukeu Pamen. 2023. Impact of imperfect vaccine, vaccine trade-off and population turnover on infectious disease dynamics. Mathematics, 11(5), p.1240. https://doi.org/10.3390/math11051240

[8] Saadi N., Chi Y.L., Ghosh S., Eggo R.M., McCarthy C.V., Quaife M., Dawa J., Jit M. and A. Vassall. 2021. Models of COVID-19 vaccine prioritisation: a systematic literature search and narrative review. BMC medicine, 19, pp.1-11. https://doi.org/10.1186/s12916-021-02190-3

[9] Maerkle, H., John S., Metzger, L., STOP-HCV Consortium, Ansari, M.A., Pedergnana, V. and Tellier, A., 2023. Inference of host-pathogen interaction matrices from genome-wide polymorphism data. bioRxiv, https://doi.org/10.1101/2023.07.06.547816.

[10] Gandon S., Day T., Metcalf C.J.E. and B.T. Grenfell. 2016. Forecasting epidemiological and evolutionary dynamics of infectious diseases. Trends in ecology & evolution, 31(10), pp.776-788. https://doi.org/10.1016/j.tree.2016.07.010

A Bayesian analysis of birth pulse effects on the probability of detecting Ebola virus in fruit batsDavid R.J. Pleydell, Innocent Ndong Bass, Flaubert Auguste Mba Djondzo, Dowbiss Meta Djomsi, Charles Kouanfack, Martine Peeters, Julien Cappelle <p>Since 1976 various species of Ebolavirus have caused a series of zoonotic outbreaks and public health crises in Africa. Bats have long been hypothesised to function as important hosts for ebolavirus maintenance, however the transmission ecology...Animal diseases, Disease Ecology/Evolution, Ecohealth, Ecology of hosts, infectious agents, or vectors, Epidemiology, Population dynamics of hosts, infectious agents, or vectors, Reservoirs, Viruses, ZoonosesAurelien Tellier2023-08-16 16:57:05 View
23 Mar 2023
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The helper strategy in vector-transmission of plant viruses

The intriguing success of helper components in vector-transmission of plant viruses.

Recommended by based on reviews by Jamie Bojko and Olivier Schumpp

Most plant-infecting viruses rely on an animal vector to be transmitted from one sessile host plant to another. A fascinating aspect of virus-vector interactions is the fact that viruses from different clades produce different proteins to bind vector receptors (1). Two major processes are described. In the “capsid strategy”, a motif of the capsid protein is directly binding to the vector receptor. In the “helper strategy”, a non-structural component, the helper component (HC), establishes a bridge between the virus particle and the vector’s receptor.   

In this exhaustive review focusing on hemipteran insect vectors, Di Mattia et al. (2) are revisiting the helper strategy in light of recent results. The authors first place the discoveries of the HC strategy in a historical context, suggesting that HC are exclusively found in non-circulative viruses (viruses that only attach to the vector). They present an overview of the nature and modes of action of helper components in the major virus clades of non-circulative viruses (Potyviruses and Caulimoviruses). Authors then detail recent advances, to which they have significantly contributed, showing that the helper strategy also appears widespread in circulative transmission categories (Tenuiviruses, Nanoviruses). 

In an extensive perspective section, they raise the question of the evolutionary significance of the existence of HC in numerous unrelated viruses, transmitted by unrelated vectors through different mechanisms. They explore the hypothesis that the helper strategy evolved several times independently in distinct viral clades and for different reasons. In particular, they present several potential benefits of plant virus HC related to virus cooperation, collective transmission and effector-driven infectivity.

As pointed out by both reviewers, this is a very clear and synthetic review. Di Mattia et al. present an exhaustive overview of virus HC-vector molecular interactions and address functionally and evolutionarily important questions. This review should benefit a large audience interested in host-virus interactions and transmission processes.

REFERENCES

(1) Ng JCK, Falk BW (2006) Virus-Vector Interactions Mediating Nonpersistent and Semipersistent Transmission of Plant Viruses. Annual Review of Phytopathology, 44, 183–212. https://doi.org/10.1146/annurev.phyto.44.070505.143325

(2) Di Mattia J, Zeddam J-L, Uzest M, Blanc S (2023) The helper strategy in vector-transmission of plant viruses. Zenodo, ver. 2 peer-reviewed and recommended by Peer Community In Infections. https://doi.org/10.5281/zenodo.7709290

The helper strategy in vector-transmission of plant virusesDi Mattia Jérémy, Zeddam Jean Louis, Uzest Marilyne and Stéphane Blanc<p>An intriguing aspect of vector-transmission of plant viruses is the frequent involvement of a helper component (HC). HCs are virus-encoded non-structural proteins produced in infected plant cells that are mandatory for the transmission success....Evolution of hosts, infectious agents, or vectors, Interactions between hosts and infectious agents/vectors, Molecular biology of infections, Molecular genetics of hosts, infectious agents, or vectors, Plant diseases, Vectors, VirusesChristine Coustau2022-10-28 17:32:39 View
29 Jan 2024
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Spring reproductive success influences autumnal malarial load in a passerine bird

Avian Plasmodium parasitaemia as an indicator of reproduction investment

Recommended by ORCID_LOGO based on reviews by Luz García-Longoria and 2 anonymous reviewers

Effects of the seasonal variations on within-host parasitaemia are still not well understood and potentially due to numerous factors, e.g. host and parasite species, host sex or age, or geographical regions. In this study, over three years in Switzerland, Pigeault et al. (2024) collected data on great tits reproductive outputs – laying date, clutch size, fledging success – to determine whether they were associated with avian Plasmodium parasitaemia before (winter), during (spring) and after (autumn) the breeding season. They focused on two lineages from two species: a highly generalist lineage Plasmodium relictum (lineage SGS1; Bensch et al. 2009) and a more specialized lineage Plasmodium homonucleophilum (lineage SW2). As previously found, they showed that parasitaemia level is low during the winter and then increase in spring (Applegate, 1970; Applegate 1971). Spring recurrences have been intensively studied but are still not well understood since many non-exclusive factors can provoke them, i.e environmental stressors, reproductive hormones, co-infections or bites of mosquitoes (Cornet et al. 2014).

Interestingly, the parasitaemia level during the winter before and during the breeding season were not associated to the reproductive success, meaning that birds in their populations with low parasitaemia during the winter had not more fledglings than the ones with a higher parasitaemia. However, the individuals who invested the most in the reproduction with a higher number of fledglings had also a higher parasitaemia in the following autumn. The number of laid eggs was not associated with the parasitaemia during the following autumn, showing that the initial investment in the reproduction is less important than the parental care (e.g. chicks feeding) in terms of mid/long term cost. The originality here is that authors followed populations during three periods of the year, which is not an easy task and rarely done in natural populations. Their results highlight the mid/long-term effect of higher resource allocation into reproduction on individuals’ immune system and ability to control parasite replication. Further analyses on various lineages and bird populations from other geographical regions (i.e. different latitudes) would be the next relevant step.

References

Applegate JE (1971) Spring relapse of Plasmodium relictum infections in an experimental field population of English sparrows (Passer domesticus). Journal of Wildlife Diseases, 7, 37–42. https://doi.org/10.7589/0090-3558-7.1.37

Applegate JE, Beaudoin RL (1970) Mechanism of spring relapse in avian malaria: Effect of gonadotropin and corticosterone. Journal of Wildlife Diseases, 6, 443–447. https://doi.org/10.7589/0090-3558-6.4.443

Bensch S, Hellgren O, Pérez‐Tris J (2009) MalAvi: a public database of malaria parasites and related haemosporidians in avian hosts based on mitochondrial cytochrome b lineages. Molecular Ecology Resources, 9, 1353-1358. https://doi.org/10.1111/j.1755-0998.2009.02692.x

Cornet S, Nicot A, Rivero A, Gandon S (2014) Evolution of plastic transmission strategies in avian malaria. PLoS Pathogens, 10, e1004308. https://doi.org/10.1371/journal.ppat.1004308

Pigeault R, Cozzarolo CS, Wassef J, Gremion J, Bastardot M, Glaizot O, Christe P (2024) Spring reproductive success influences autumnal malarial load in a passerine bird. bioRxiv ver 3. Peer reviewed and recommended by Peer Community In Infections. https://doi.org/10.1101/2023.07.28.550923

Spring reproductive success influences autumnal malarial load in a passerine birdRomain Pigeault, Camille-Sophie Cozzarolo, Jérôme Wassef, Jérémy Gremion, Marc Bastardot, Olivier Glaizot, Philippe Christe<p>Although avian haemosporidian parasites are widely used as model organisms to study fundamental questions in evolutionary and behavorial ecology of host-parasite interactions, some of their basic characteristics, such as seasonal variations in ...Interactions between hosts and infectious agents/vectors, ParasitesClaire Loiseau Carolina Chagas, Anonymous, Luz García-Longoria2023-08-11 14:14:56 View
23 Jan 2023
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Whole blood transcriptome profiles of trypanotolerant and trypanosusceptible cattle highlight a differential modulation of metabolism and immune response during infection by Trypanosoma congolense

Whole genome transcriptome reveals metabolic and immune susceptibility factors for Trypanosoma congolense infection in West-African livestock

Recommended by based on reviews by 2 anonymous reviewers

African trypanosomiasis is caused by to the infection of a protozoan parasite of the Trypanosoma genus. It is transmitted by the tsetse fly, and is largely affecting cattle in the sub-humid areas of Africa, causing a high economic impact. However, not all the bovine strains are equally susceptible to the infection (1). 

In order to dissect the mechanisms underlying susceptibility to African trypanosoma infection, Peylhard et al (2) performed blood transcriptional profiles of trypanotolerant, trypanosensitive and mixed cattle breeds, before and after experimental infection with T. congolense

First of all, the authors have characterized the basal transcriptional profiles in the blood of the different breeds under study, which could be classified in a wide array of functional pathways. Of note, after infection some pathways were consistently enriched in all the group tested. Among them, the immune system-related ones were again on the top functions reported. The search for specific canonical pathways pointed to a prominent role of lipid and cholesterol-related pathways, as well as mitochondrial function and B and T lymphocyte activation.

However, the analysis of infected animals demonstrated that trypanosusceptible animals showed a stronger transcriptomic reprogramming, highly enriched in specific metabolic and immunological pathways. It is worthy to highlight striking differences in genes involved in immune signal transduction, cytokines and markers of different leukocyte subpopulations.

This work represents undoubtedly a significant momentum in the field, since the authors explore in deep a wide panel of cattle breeds representing the majority of West-African taurine and zebu in a systematic way. Since the animals were studied at different timepoints after infection, future longitudinal analyses of these datasets will be providing a precious insight on the kinetics of immune and metabolic reprogramming associated with susceptibility and tolerance to African trypanosoma infection, widening the application of this interesting study into new therapeutic interventions.

References

1. Berthier D, Peylhard M, Dayo G-K, Flori L, Sylla S, Bolly S, Sakande H, Chantal I, Thevenon S (2015) A Comparison of Phenotypic Traits Related to Trypanotolerance in Five West African Cattle Breeds Highlights the Value of Shorthorn Taurine Breeds. PLOS ONE, 10, e0126498. https://doi.org/10.1371/journal.pone.0126498

2. Peylhard M, Berthier D, Dayo G-K, Chantal I, Sylla S, Nidelet S, Dubois E, Martin G, Sempéré G, Flori L, Thévenon S (2022) Whole blood transcriptome profiles of trypanotolerant and trypanosusceptible cattle highlight a differential modulation of metabolism and immune response during infection by Trypanosoma congolense. bioRxiv, 2022.06.10.495622, ver. 2 peer-reviewed and recommended by Peer Community Infections. https://doi.org/10.1101/2022.06.10.495622.

Whole blood transcriptome profiles of trypanotolerant and trypanosusceptible cattle highlight a differential modulation of metabolism and immune response during infection by Trypanosoma congolenseMoana Peylhard, David Berthier, Guiguigbaza-Kossigan Dayo, Isabelle Chantal, Souleymane Sylla, Sabine Nidelet, Emeric Dubois, Guillaume Martin, Guilhem Sempéré, Laurence Flori, Sophie Thévenon<p>Animal African trypanosomosis, caused by blood protozoan parasites transmitted mainly by tsetse flies, represents a major constraint for millions of cattle in sub-Saharan Africa. Exposed cattle include trypanosusceptible indicine breeds, severe...Animal diseases, Genomics, functional genomics of hosts, infectious agents, or vectors, Resistance/Virulence/ToleranceConcepción MarañónAnonymous, Anonymous2022-06-14 17:06:57 View
29 Jan 2024
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Celebrating the 20th Anniversary of the First Xanthomonas Genome Sequences – How Genomics Revolutionized Taxonomy, Provided Insight into the Emergence of Pathogenic Bacteria, Enabled New Fundamental Discoveries and Helped Developing Novel Control Measures – A Perspective from the French Network on Xanthomonads

Advancing Pathogen Genomics: A Comprehensive Review of the Xanthomonas(*) Genome's Impact on Bacterial Research and Control Strategies

Recommended by ORCID_LOGO based on reviews by Boris Vinatzer and 3 anonymous reviewers

The paper titled "Celebrating the 20th Anniversary of the First Xanthomonas Genome Sequences – How Genomics Revolutionized Taxonomy Provided Insight into the Emergence of Pathogenic Bacteria Enabled New Fundamental Discoveries and Helped Developing Novel Control Measures – A Perspective from the French Network on Xanthomonads" by Ralf Koebnik et al. (2023) is an insightful contribution to the field of genomics and its application in understanding pathogenic bacteria, particularly Xanthomonas. This comprehensive review offers a unique perspective from the French Network on Xanthomonads, underscoring the significant advancements in taxonomy, pathogen emergence, and development of control strategies due to genomic research.

One of the paper's main strengths is its thorough exploration of how genomics has revolutionized our understanding of Xanthomonas and other pathogenic bacteria. It sheds light on the evolution and emergence of these pathogens, contributing significantly to the development of novel and effective control measures. The authors' detailed account of the historical progress and current state of genomics in this field highlights its pivotal role in guiding future research and practical applications in managing bacterial diseases.

Moreover, the paper emphasizes the importance of collaborative efforts and the sharing of knowledge within scientific networks, as exemplified by the French Network on Xanthomonas. This approach not only enriches the study but also serves as a model for future collaborative research endeavors.

In conclusion, the work of Koebnik et al. is a valuable resource for researchers, policymakers, and practitioners in the field of plant pathology and genomics. It not only provides a comprehensive overview of the advances in genomics related to Xanthomonas but also illustrates the broader impact of genomic studies in understanding and managing pathogenic bacteria.

References

Ralf Koebnik, Sophie Cesbron, Nicolas W. G. Chen, Marion Fischer-Le Saux, Mathilde Hutin, Marie-Agnès Jacques, Laurent D. Noël, Alvaro Perez-Quintero, Perrine Portier, Olivier Pruvost, Adrien Rieux, And Boris Szurek (2024) Celebrating the 20th anniversary of the first Xanthomonas genome gequences – How genomics revolutionized taxonomy, provided insight into the emergence of pathogenic bacteria, enabled new fundamental discoveries and helped developing novel control measures – A perspective from the French network on Xanthomonads. Zenodo ver. 3, peer-reviewed and recommended by Peer Community in Infections. https://doi.org/10.5281/zenodo.8223857

Celebrating the 20th Anniversary of the First Xanthomonas Genome Sequences – How Genomics Revolutionized Taxonomy, Provided Insight into the Emergence of Pathogenic Bacteria, Enabled New Fundamental Discoveries and Helped Developing Novel Control ...Ralf Koebnik, Sophie Cesbron, Nicolas W. G. Chen, Marion Fischer-Le Saux, Mathilde Hutin, Marie-Agnès Jacques, Laurent D. Noël, Alvaro Perez-Quintero, Perrine Portier, Olivier Pruvost, Adrien Rieux, And Boris Szurek<p>In this Opinion paper, members of the French Network on Xanthomonads give their personal view on what they consider to be some of the groundbreaking discoveries in the field of molecular plant pathology over the past 20 years. By celebrating th...Epidemiology, Evolution of hosts, infectious agents, or vectors, Genomics, functional genomics of hosts, infectious agents, or vectors, Interactions between hosts and infectious agents/vectors, Molecular biology of infections, Molecular genetics o...Damien François Meyer2023-08-09 10:37:15 View
24 Jun 2024
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Differences in specificity, development time and virulence between two acanthocephalan parasites, infecting two cryptic species of Gammarus fossarum

Gammarid is not equal gammarid for acanthocephalan parasites

Recommended by based on reviews by 2 anonymous reviewers

The question on the role of different alternative hosts in the life cycle of acanthocephalan parasites has not been fully resolved to date. There is some information on the use of fish hosts in the genus Pomphorhynchus (Perrot-Minnot et al. 2019). It is known that acanthocephalans of the genus Pomphorhynchus can infect a number of different amphipod species (e.g. Bauer et al. 2000; Cornet et al. 2010; Dezfuli et al. 1999) but it is not clear if some host species might be more “advantageous” for the parasite, or if the parasite is more virulent to some host species than to others. Bauer et al. (2024) investigated different well characterized cryptic lineages of Gammarus fossarum (Weiss et al. 2013) for their susceptibility for two Pomphorhynchus sp. The results show that there is a difference in susceptibility to acanthocephalans between different linages of G. fossarum. Additionally, a parasite species specific difference was detected: the difference in susceptibility was more pronounced for P. tereticollis than for P. laevis. P. tereticollis was less virulent and developed slower than P. laevis (in G. fossarum).

Besides the improved understanding of the biology of acanthocephalan parasites, this study clearly points out that we have to be careful with putting the “generalist” label on parasites simply due to the number of alternative host species we find them in. Instead, we should always have in mind that some of these hosts might be less suitable for the parasite than others when comparing quantitative data on the infection success.

I highly appreciate the experimental approach taken that allows more profound conclusions than evaluations of field data. Experiments and analyses have been conducted well. I think this paper is significantly enhancing our knowledge on the specificity for the intermediate host. I find it highly remarkable that this was even found among different host lineages.

References

Bauer, A., Trouve, S., Gregoire, A., Bollache, L., Cezilly, F. (2000) Differential influence of Pomphorhynchus laevis (Acanthocephala) on the behaviour of native and invader gammarid species. International Journal for Parasitology, 30(14), 1453-1457. https://doi.org/10.1016/s0020-7519(00)00138-7

Bauer, A., Develay Nguyen, L., Motreuil, S., Teixeira, M., Debrosse, N., Rigaud, T. (2024) Experimental infections reveal differences in specificity, development time and virulence between the acanthocephalan parasite Pomphorhynchus tereticollis and its sympatric counterpart P. laevis, in two cryptic species of Gammarus fossarum. HAL, Ver. 2, Peer-Reviewed and Recommended by Peer Community in Infections, hal-04455823. https://hal.science/hal-04455823  

Cornet, S., Sorci, G., Moret, Y. (2010) Biological invasion and parasitism: invaders do not suffer from physiological alterations of the acanthocephalan Pomphorhynchus laevis. Parasitology, 137(1), 137-147. https://doi.org/10.1017/S0031182009991077 

Dezfuli, B.S., Rossetti, E., Bellettato, C.M., Maynard, B.J. (1999) Pomphorhynchus laevis in its intermediate host Echinogammarus stammeri in the River Brenta, Italy. Journal of Helminthology, 73(2), 95-102. https://doi.org/10.1017/S0022149X00700277 

Perrot-Minnot, M.J., Guyonnet, E., Bollache, L., Lagrue, C. (2019) Differential patterns of definitive host use by two fish acanthocephalans occurring in sympatry: Pomphorhynchus laevis and Pomphorhynchus tereticollis. International Journal for Parasitology: Parasites and Wildlife, 8, 135-144. https://doi.org/10.1016/j.ijppaw.2019.01.007 

Weiss, M., Macher, J.N., Seefeldt, M.A., Leese, F. (2013) Molecular evidence for further overlooked species within the Gammarus fossarum complex (Crustacea: Amphipoda). Hydrobiologia, 721(1), 165-184. https://doi.org/10.1007/s10750-013-1658-7

 

Differences in specificity, development time and virulence between two acanthocephalan parasites, infecting two cryptic species of *Gammarus fossarum*Alexandre Bauer, Lucie Develay Nguyen, Sébastien Motreuil, Maria Teixeira, Nelly Debrosse, Thierry Rigaud<p style="text-align: justify;">Multi-host parasites can exploit various host species that differ in abundance and susceptibility to infection, which will contribute unequally to their transmission and fitness. Several species of acanthocephalan m...Ecology of hosts, infectious agents, or vectors, Evolution of hosts, infectious agents, or vectors, Interactions between hosts and infectious agents/vectors, Molecular genetics of hosts, infectious agents, or vectors, Parasites, Resistance/Virulen...Daniel Grabner2024-02-14 13:39:19 View
02 Jun 2023
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Multiple hosts, multiple impacts: the role of vertebrate host diversity in shaping mosquito life history and pathogen transmission

What you eat can eliminate you: bloodmeal sources and mosquito fitness

Recommended by based on reviews by Francisco C. Ferreira and 1 anonymous reviewer

​​Diptera-borne pathogens rank among the most serious health threats to vertebrate organisms around the world, particularly in tropical areas undergoing strong human impacts – e.g., urbanization and farming –, where social unrest and poor economies exacerbate the risk (Allen et al. 2017; Robles-Fernández et al. 2022). Although scientists have acquired a detailed knowledge on the life-history of malaria parasites (Pacheco and Escalante 2023), they still do not have enough information about their insect vectors to make informed management and preventive decisions (Santiago-Alarcon 2022).

In this sense, I am pleased to recommend the study of Vantaux et al. (2023), where authors conducted an experimental and theoretical study to analyzed how the diversity of blood sources (i.e., human, cattle, sheep, and chicken) affected the fitness of the human malaria parasite – Plasmodium falciparum – and its mosquito vector – Anopheles gambiae s.l.

The study was conducted in Burkina Faso, West Africa. Interestingly, authors did not find a significant effect of blood meal source on parasite development, and a seemingly low impact on the fitness of mosquitoes that were exposed to parasites. However, mosquitoes’ feeding rate, survival, fecundity, and offspring size were negatively affected by the type of blood meal ingested. In general, chicken blood represented the worst meal source for the different measures of mosquito fitness, and sheep blood seems to be the least harmful. This result was supported by the theoretical model, where vectorial capacity was always better when mosquitoes fed on sheep blood compared to cow and chicken blood. Thus, the knowledge generated by this study provides a pathway to reduce human infection risk by managing the diversity of farm animals. For instance, transmission to humans can decrease when chickens and cows represent most of the available blood sources in a village.

These results along with other interesting details of this study, represent a clear example of the knowledge and understanding of insect vectors that we need to produce in the future, particularly to manage and prevent hazards and risks (sensu Hoseini et al. 2017).

REFERENCES

Allen T., et al., Global hotspots and correlates of emerging zoonotic diseases. Nat. Commun. 8, 1124. (2017). https://doi.org/10.1038/s41467-017-00923-8

Hosseini P.R., et al., Does the impact of biodiversity differ between emerging and endemic pathogens? The need to separate the concepts of hazard and risk. Philos. Trans. R. Soc. Lond. B Biol. Sci. 372, 20160129 (2017). https://doi.org/10.1098/rstb.2016.0129

Pacheco M.A., and Escalante, A.A., Origin and diversity of malaria parasites and other Haemosporida. Trend. Parasitol. (2023) https://doi.org/10.1016/j.pt.2023.04.004

Robles-Fernández A., et al., Wildlife susceptibility to infectious diseases at global scales. PNAS 119: e2122851119. (2022). https://doi.org/10.1073/pnas.2122851119

Santiago-Alarcon D. A meta-analytic approach to investigate mosquitoes’ (Diptera: Culicidae) blood feeding preferences from non-urban to urban environments. In: Ecology and Control of Vector-borne Diseases, vol. 7 (R.G. Gutiérrez-López, J.G. Logan, Martínez-de la Puente J., Eds). Pp. 161-177. Wageningen Academic Publishers. eISBN: 978-90-8686-931-2 | ISBN: 978-90-8686-379-2 (2022).

Vantaux A. et al. Multiple hosts, multiple impacts: the role of vertebrate host diversity in shaping mosquito life history and pathogen transmission. bioRxiv, ver. 3 peer-reviewed and recommended by Peer Community in Infections (2023). https://doi.org/10.1101/2023.02.10.527988

Multiple hosts, multiple impacts: the role of vertebrate host diversity in shaping mosquito life history and pathogen transmissionAmélie Vantaux, Nicolas Moiroux, Kounbobr Roch Dabiré, Anna Cohuet, Thierry Lefèvre<p style="text-align: justify;">The transmission of malaria parasites from mosquito to human is largely determined by the dietary specialization of <em>Anopheles mosquitoes</em> to feed on humans. Few studies have explored the impact of blood meal...Ecology of hosts, infectious agents, or vectors, Parasites, VectorsDiego Santiago-Alarcon2023-02-13 11:02:58 View