Cucumber mosaic virus (CMV; Cucumovirus genus; Bromoviridae family) is one of the early model plant viruses for which knowledge has accumulated for over a hundred years (Roossinck, 2001). Features such as its ability to be mechanically transmitted; its strong accumulation in infected hosts, which facilitates purification; and the availability of several distinct infectious cDNAs make CMV particularly suitable for experimental manipulation and have probably contributed to its status of model organism, which it still retains (Roossinck, 2001; Jacquemond, 2012). Besides its importance in research, CMV is also of great agricultural and economic importance. Indeed, CMV infects more than 100 plant families, is a major economic threat to multiple plant crops, and is distributed worldwide (Lepage et al., 2025). As plant viruses often primarily rely on insect vectors for transmission, virus disease epidemiology in natural settings is complex and involves interactions between plants, the virus, its vector(s) and to some extent the environment. Vector-mediated transmission is an important aspect of these interactions, not only because it drives both the specificity and the diffusion dynamics of the disease but also because most plant virus control strategies target the vector rather than the virus itself (Whitfield et al., 2015). As a consequence, vector-mediated transmission is often qualitatively and quantitatively evaluated in experimental settings involving greenhouses or climatic chambers. Experimental settings are designed according to the question addressed and the biological characteristics of the host plant, the virus, and the vector. For example, knowing whether a virus can be transmitted through plant-to-plant contact is crucial for study design, as non-vector-mediated transmission could compromise the results.

This study by Chateau et al. aimed to assess whether CMV can be transmitted through plant-to-plant contact, a means of transmission never reported before for this virus. The authors used an experimental design mimicking a plausible scenario of an experimental setting where plants are positioned in direct contact with one another to enable the movement of apterous aphids between plants. They clearly show that CMV can be transmitted through plant-to-plant contact both within and between species for pepper and several weed species. This result is valuable to the scientific community as it calls for the implementation of new measures in some experimental protocols in order to decrease the risk of unwanted contact-based CMV transmission, thereby improving the reliability of experimental designs. It is also a reminder to both private and public actors in phytopathology research that including proper controls in study design is crucial to avoid relying too strongly on commonly admitted assumptions.

I agreed to serve as recommender for this paper because of the originality of the scientific approach that led to this experiment and its results. As a recommender, I particularly appreciated that the authors, rather than assuming CMV cannot be transmitted through contact, directly tested this and obtained unexpected results. As the authors note in their response to the reviewers, this study is part of a larger project measuring aphid-mediated CMV transmission among six plant species. I therefore infer that this contact-based experiment was originally performed as a negative control to confirm that the transmission observed in their main assay was indeed aphid-mediated. This paper, a by-product of their main study, is a fitting return on the substantial effort required to implement high-quality protocols.

During the review process, the reviewers highlighted the value of these results for the scientific community studying CMV transmission and noted that the study is clear and easy to follow, requiring very few changes from the initial submission. The review process nevertheless improved the manuscript in several ways. First, it helped explain more precisely the context and the methods of the study to the reader, with aspects such as the choice of tested plant species and the description of the protocol organization in experiments, combinations, and replicates. It also led to the manuscript now clearly stating recommendations for future experimental work on plant virus transmission, including the use of negative controls.

References

Chateau L, Szadkowski M, Théodore J, Rimbaud L (2025) CMV can spread through plant to plant contact: implications for experimental practices. bioRxiv, ver.3 peer-reviewed and recommended by PCI Infections 2025.07.30.667662. https://doi.org/10.1101/2025.07.30.667662

Jacquemond M (2012) Chapter 13 - Cucumber Mosaic Virus. In: Advances in Virus Research (eds Loebenstein G, Lecoq H), pp. 439–504. Academic Press. https://doi.org/10.1016/B978-0-12-394314-9.00013-0

Lepage E, Szadkowski M, Girardot G, Pascal M, Dumeaux P, Papaïx J, Moury B, Rimbaud L (2025) Cucumber Mosaic Virus Degrades Pepper Fruit Production, Marketability and Organoleptic Quality, With Isolate-Specific Effects. Plant Pathology, 74, 1244–1255. https://doi.org/10.1111/ppa.14086

Roossinck MJ (2001) Cucumber mosaic virus, a model for RNA virus evolution. Molecular Plant Pathology, 2, 59–63. https://doi.org/10.1046/j.1364-3703.2001.00058.x

Whitfield AE, Falk BW, Rotenberg D (2015) Insect vector-mediated transmission of plant viruses. 60th Anniversary Issue, 479–480, 278–289. https://doi.org/10.1016/j.virol.2015.03.026

In the context of climate change and rapid urbanization, re-naturing cities is essential for sustainability and human well-being. However, this process can also heighten the risk of vector-borne diseases (VBDs) that affect both humans and animals, underscoring the need to integrate health considerations into urban policy. Mercat et al (2025) carried out a meta-analysis on the relationships between urban green infrastructures (UGIs), vectors and the pathogens transmitted by these vectors, and attempt to propose courses of action to improve animal and human health, and recommendations to plan urban actions to reduce the risk of emergence of VBDs. 

This review is very interesting because it provides an insight into the complexity of studies on the impact of UGIs on several vectors and pathogens. The review work is extensive and acts as a statement on the topics. The article showed that the effects may vary depending on the vector-pathogen system, mainly due to the ecology of vectors but also their hosts. According to this article, Aedes aegypti was generally negatively associated with UGIs, while Ae. albopictus showed positive associations. Concerning the main Aedes-borne transmitted pathogen Dengue virus (DENV), results were less consistent as DENV is transmitted by both species, which responded differently to UGIs. For Culex mosquitoes and the transmission of the West Nile Virus (WNV), the authors showed that both mosquito abundance and host seroprevalence tended to be higher in residential areas with moderate vegetation cover compared to urban forests or areas with dense vegetation. Observed variations of response may be due to the complexity of WNV transmission dynamics, which is influenced by various factors, including plasticity in the feeding behavior of the several mosquito species, host availability, and diversity in the ability of bird host species to amplify and further transmit the virus to the vector mosquitoes. Although the authors noticed that the influence of UGIs on Anopheles mosquito populations and associated diseases was context-specific, the abundance of mosquitoes transmitting pathogens causing malaria, were positively associated with UGIs, especially urban agriculture. Concerning ticks, particularly Ixodes ricinus, the authors demonstrated that this species was location-specific and depended on the time of year, but was mainly positively associated with UGIs that include wooded areas. Borrelia infection rates in ticks were strongly linked to the presence and movement of competent hosts, particularly in woodlands or connected urban green spaces, reflecting the influence of UGIs on tick vector populations. For other tick-borne pathogens, which were less studied, the meta-analysis did not find any consistent pattern between infection rates in ticks and UGIs.

The authors produced a hard work to answer any reviewers’ comments and questions, which allowed to precise and synthetize information provided by the article. I highly recommend this preprint as a reference for stakeholders’ involvement in the planning of UGIs in urban areas through integrative approaches.

References

Mathilde Mercat, Colombine Bartholomee, Florence Fournet, Magdalena Alcover Amengual, Maria Bourquia, Emilie Bouhsira, Anthony Cornel, Xavier Fernandez-Cassi, Didier Fontenille, Adolfo Ibanez-Justicia, Renaud Marti, Nicolas Moiroux, El Hadji Niang, Woutrina Smith, Jeroen Spitzen, Tessa Visser, Constantianus J. Koenraadt, Frederic Simard (2025) Green cities and the risk for vector-borne disease transmission for humans and animals: a scoping review. bioRxiv, ver.4 peer-reviewed and recommended by PCI Infections https://doi.org/10.1101/2025.04.01.646559

The battle against malaria has had many victories in recent decades but remains far from over. Insecticide-treated mosquito nets (ITNs) have been largely responsible for massive drops in incidence and remain a key public health tool even as more recent strategies such as vaccination have become available (Bhatt et al., 2015). However, there is debate about the most effective type of ITNs to use — those that deter vectors, those that attract vectors, or those that simply provide an inert barrier. While attractive ITNs work to more effectively kill mosquitoes by increasing their contact with the insecticide, they raise concerns of unintended consequences for community transmission and malaria control if they also increase the risk of bites, particularly when the nets are not in full use protecting the human hosts in their proximity. Furthermore, some empirical studies have found that ITNs intended to be repellent may actually act as attractors, either after frequent washing (Moiroux et al., 2017) or when faced with mosquitos resistant to the insecticide (Porciani et al., 2017), so it is important to understand the implications for this phenomenon for control operations currently in progress.

To study the theoretical potential for attractive ITNs to reduce community transmission of malaria, Moiroux and Pennetier (2025) developed a compartmental model designed to compare the effects of repellent, inert, and attractive ITNs on malaria transmission. Prior modeling work had found that repellent ITNs were theoretically expected to be less effective than inert ITNs at controlling malaria transmission at the community level but did not consider the effect of attractive ITNs (Killeen et al., 2011). Despite this result, and the clear importance of ITNs as a public health tool for risk mitigation, it is puzzling that such a study had not yet been conducted.

Moiroux and Pennetier (2025) indeed found that attractive ITNs are expected to outperform inert and repellent ITNs in reducing malaria transmission, with only quantitative differences in this effect across the full range of parameter combinations that they tested. They also showed that the attractive ITNs are expected to remain more effective even in the face of vector resistance mechanisms. While the influence of assumptions made remain to be explored, such as a lack of spatial or temporal heterogeneity in population structure or parameter values, these findings present an intriguing hypothesis to test.

Importantly, there is currently no registered cluster-randomized trial evaluating attractive ITNs in the field. The closest empirical analogues are experimental-hut studies that combine nets with attractants (Wagman et al., 2018; Furnival-Adams et al., 2020), as well as trials looking into adding attractive targeted sugar baits (ATSBs) to control operations (discussed in Zembere, 2024). Structural interventions such as insecticide-treated eave nets and window screens are also being trialed (Asale et al., 2022), but these differ conceptually from ITNs designed to draw in host-seeking mosquitoes. This underscores that the modeling study by Moiroux and Pennetier (2025) is breaking new ground and provides a timely call for empirical evaluation.

In conclusion, the results of Moiroux and Pennetier (2025) are a call to both public health and industry alike to investigate this shift to attractive ITNs as a potential innovation in the fight against malaria. While the theory requires field validation, the results could have impacts well beyond malaria, as the concept of vector attraction or repulsion for control is common across a wide array of infectious diseases that threaten global health.

References

Asale, A., Kassie, M., Abro, Z. et al. (2022). The combined impact of LLINs, house screening, and pull-push technology for improved malaria control and livelihoods in rural Ethiopia: study protocol for household randomised controlled trial. BMC Public Health, 22(930). https://doi.org/10.1186/s12889-022-12919-1

Bhatt, S., Weiss, D. J., Cameron, E., Bisanzio, D., Mappin, B., Dalrymple, U., … & Gething, P. W. (2015). The effect of malaria control on Plasmodium falciparum in Africa between 2000 and 2015. Nature, 526(7572), 207–211. https://doi.org/10.1038/nature15535

Furnival-Adams, J. E., Camara, S., Rowland, M., Koffi, A. A., Ahoua Alou, Oumbouke, W. A., & N’Guessan, R. (2020). Indoor use of attractive toxic sugar bait in combination with long-lasting insecticidal nets against pyrethroid-resistant Anopheles gambiae: An experimental hut trial in Mbé, central Côte d’Ivoire. Malaria Journal, 19(11). https://doi.org/10.1186/s12936-019-3095-1

Killeen, G. F., Chitnis, N., Moore, S. J., Okumu, F. O., & Kiware, S. S. (2011). Target product profile choices for intra-domiciliary malaria vector control pesticide products: Repel or kill? Malaria Journal, 10(207). https://doi.org/10.1186/1475-2875-10-207

Moiroux, N., Chandre, F., Hougard, J. M., Corbel, V., & Pennetier, C. (2017). Remote Effect of Insecticide-Treated Nets and the Personal Protection against Malaria Mosquito Bites. PLOS ONE, 12(1), e0170732. https://doi.org/10.1371/journal.pone.0170732

Moiroux, N., & Pennetier, C. (2025) The potential of attractive insecticide-treated nets (ITNs) in reducing malaria transmission: a modeling study. medRxiv, ver.5, peer-reviewed and recommended by PCI Infections https://doi.org/10.1101/2025.04.02.25325102

Porciani, A., Diop, M., Moiroux, N., Kadoke-Lambi, T., Cohuet, A., et al. (2017). Influence of pyrethroïd-treated bed net on host seeking behavior of Anopheles gambiae s.s. carrying the kdr allele. PLOS ONE, 12(7), e0164518. https://doi.org/10.1371/journal.pone.0164518

Wagman, J. M., Grieco, J. P., Bautista, K., Polanco, J., Bricheno, I., King, R., & Achee, N. L. (2015). The field evaluation of a push-pull system to control malaria vectors in northern Belize, Central America. Malaria Journal, 14(184). https://doi.org/10.1186/s12936-015-0692-5

Zembere, K. (2024). The potential for attractive toxic sugar baits to complement core malaria interventions strategies: the need for more evidence. Malaria Journal, 23(356). https://doi.org/10.1186/s12936-024-05161-0

The tomato yellow leaf curl disease (TYLCD) has long plagued tomato crops across the western Mediterranean. The virus landscape has long included both native (TYLCSaV) and introduced (TYLCV) begomoviruses (Lefeuvre et al., 2010), along with a mosaic of recombinants, firstly detected in 1998 for TYLCSaV/TYLCV (Monci et al., 2002).

Despite shared vectors and active trade between Spain, Italy, and Morocco, regional differences in virus populations were evident through 2014 with distinct recombinants between countries (Belabess et al., 2015; Pano et al., 2018). The recommended publication (Garnier et al., 2024) therefore addresses the question of whether these patterns have persisted over time.

To find out, researchers analyzed 105 tomato samples collected between 2015 and 2019, using targeted PCR assays to distinguish between virus species, strains, and recombinants, especially the so-called Srec (short-fragment) and Lrec (long-fragment) recombinants.

The findings reveal two key insights: (1) Geographic signatures persist as Morocco harbors TYLCV-IS76 exclusively and Italy hosts TYLCV-IS141 and a newly identified Srec recombinant, TYLCV-IMS60-2400; (2) A striking population shift across all countries as Srec recombinants now dominate, with no Lrec forms detected, resulting in a marked change from earlier decades.

So, selective pressures independently favored the same recombinant genomic configuration, yet with distinct strains. One hypothesis from the authors is that the selective sweep might have been driven by Ty-1 resistance genes in modern tomato cultivars. As breeders deploy resistance, viruses evolve in turn, highlighting a classic case of adaptive viral evolution under host-imposed pressure.

References

Belabess, Z., Dallot, S., El-Montaser, S., Granier, M., Majde, M., Tahiri, A., Blenzar, A., Urbino, C., Peterschmitt, M., 2015. Monitoring the dynamics of emergence of a non-canonical recombinant of Tomato yellow leaf curl virus and displacement of its parental viruses in tomato. Virology 486, 291-789. https://doi.org/10.1016/j.virol.2015.09.011

Granier, M., Tomassoli, L., Manglli, A., Nannini, M., Peterschmitt, M., Urbino, C., 2019. First Report of TYLCV-IS141, a Tomato Yellow Leaf Curl Virus Recombinant Infecting Tomato Plants Carrying the Ty-I821 Resistance Gene in Sardinia (Italy). Plant Dis 103, 1437-1437. https://doi.org/10.1094/PDIS-09-18-1558-PDN 

Granier, M., Faize, M., Passera, S., Urbino, C.,Peterschmitt, M. (2024) Population shifts in begomoviruses associated with tomato yellow leaf curl disease in western Mediterranean countries. bioRxiv, ver.3 peer-reviewed and recommended by PCI Infections https://doi.org/10.1101/2024.08.09.607290

Lefeuvre P, Martin DP, Harkins G, Lemey P, Gray AJA, et al. (2010) The Spread of Tomato Yellow Leaf Curl Virus from the Middle East to the World. PLOS Pathogens 6(10): e1001164.  https://doi.org/10.1371/journal.ppat.1001164   

Monci, F., Sanchez-Campos, S., Navas-Castillo, J., Moriones, E., 2002. A natural recombinant between the geminiviruses Tomato yellow leaf curl Sardinia virus and Tomato yellow leaf curl virus exhibits a novel pathogenic phenotype and is becoming prevalent in Spanish populations. Virology 303, 317-326. https://doi.org/10.1006/viro.2002.1633

Panno, S., Caruso, A.G. & Davino, S. The nucleotide sequence of a recombinant tomato yellow leaf curl virus strain frequently detected in Sicily isolated from tomato plants carrying the Ty-1 resistance gene. Arch Virol 163, 795–797 (2018). https://doi.org/10.1007/s00705-017-3674-9

The rapid rise of high-throughput sequencing (HTS) technologies has profoundly transformed the fields of research and diagnostics, enabling the massive discovery of new viral species throughout the living world. In somewhat counterintuitive ways, the abundance of newly identified species insufficiently characterized for their biological properties may negatively impact biosecurity risk assessment required to prevent the introduction of harmful organisms, protect crops and maintain the smooth flow of agricultural trade (Massart et al., 2017). 

In this context, the paper of Fox et al. (2025) pinpoint several issues and propose avenues for improvement given that the resources required for the characterization of these new species will not increase proportionally. The aim of these considerations is to anticipate and reduce the growing bottleneck associated with the time-consuming risk assessment of these massive discoveries of new species.

Indeed, HTS provides massive amounts of sequencing data that have the potential to accelerate risk management, but on the other hand, the absence of comprehensive metadata such as the description of analytical pipeline or sampling procedures may result in burdensome and misguided regulation that will have negative impact on biosafety.

The article follows on from an initial article published more than 10 years ago (MacDiarmid et al., 2013), which highlighted the new needs associated with the expected emergence of a “deluge of discoveries” of new viral species. The importance of continuing efforts to characterize the biological properties of newly discovered viral species is illustrated through updated examples. These efforts should go hand in hand with strengthened baseline surveillance, particularly in underexplored regions of the world and in wild plant species, which represent a major reservoir of viral diversity. In the present paper, the authors also propose the use of vernacular virus names for risk analyses and the implementation of regulatory measures. Vernacular names are indeed less ambiguous and more stable than species names, which are the preserve of the ICTV and subject to changes in taxonomic rules and the structure of the classification itself. Lastly, the paper stresses that the sharing of data and expertise must take place within a framework of trust and equity. 

Finally, the paper reminds us that in a world of globalized trade, the biosecurity of all depends on the biosecurity of every single region of the world, including those with limited research capabilities. In a context of widespread use of post-genomic technologies associated with risk assessment and regulation, the authors emphasize the need for reflection on how these technologies can be made available to all, in a more inclusive approach within a framework of international cooperation. Beyond its immediate contribution, this article offers a relevant and well-documented framework that can serve as a reference for assessing progress in the years to come.

References

Massart S, Candresse T, Gil J, et al., 2017. A framework for the evaluation of biosecurity, commercial, regulatory, and scientific impacts of plant viruses and viroids identified by NGS technologies. Frontiers in Microbiology 8, 45. https://doi.org/10.3389/fmicb.2017.00045

Macdiarmid R, Rodoni B, Melcher U, Ochoa-Corona F, Roossinck M, 2013. Biosecurity implications of new technology and discovery in plant virus research. PLoS pathogens 9, e1003337. https://doi.org/10.1371/journal.ppat.1003337

Adrian Fox, Marleen Botermans, Heiko Ziebell, Aimee R. Fowkes, Nuria Fontdevila-Pareta, Sebastien Massart, Brendan Rodoni, Kar Mun Chooi, Jan Kreuze, Lava Kumar, Wilmer Cueller, Monica Carvajal-Yepes, RObin M. MacDiarmid (2025) Implications of high throughput sequencing of plant viruses in biosecurity – a decade of progress?. Zenodo, ver.3 peer-reviewed and recommended by PCI Infections https://doi.org/10.5281/zenodo.13881572