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Arboviruses, i.e., viruses transmitted by blood-sucking arthropods, trigger significant global epidemics. Over the past 20 years, the frequency of the (re-)emergence of these pathogens, particularly those transmitted by Aedes and Culex mosquitoes, has dramatically increased. Therefore, understanding how human behavior is modulating population exposure to these viruses is of particular importance. This synthesis explores human behavioral factors driving human exposure to arboviruses, focusing on household surroundings, socio-economic status, human activities, and demographic factors. Household surroundings, such as the lack of water access, greatly influence the risk of arbovirus exposure by promoting mosquito breeding in stagnant water bodies. Socio-economic status, such as low income or low education, is correlated to an increased incidence of arboviral infections and exposure. Human activities, particularly those practiced outdoors, as well as geographical proximity to livestock rearing or crop cultivation, inadvertently provide favorable breeding environments for mosquito species, escalating the risk of virus exposure. However, the effects of demographic factors like age and gender can vary widely through space and time. While climate and environmental factors crucially impact vector development and viral replication, household surroundings, socio-economic status, human activities, and demographic factors are key drivers of arbovirus exposure. This article highlights that human behavior creates a complex interplay of factors influencing the risk of mosquito-borne virus exposure, operating at different temporal and spatial scales. To increase awareness among human populations, we must improve our understanding of these complex factors. [ABSTRACT FROM AUTHOR]

Introduction: Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, is a major public health problem in the Americas, and existing drugs have severe limitations. In this context, a vaccine would be an attractive alternative for disease control. One of the difficulties in developing an effective vaccine lies in the high genetic diversity of T. cruzi. In this study, we evaluated the level of sequence diversity of the leading vaccine candidate Tc24 in multiple parasite strains. Methods and Results: We quantified its level of polymorphism within and between T. cruzi discrete typing units (DTUs) and how this potential polymorphism is structured by different selective pressures. We observed a low level of polymorphism of Tc24 protein, weakly associated with parasite DTUs, but not with the geographic origin of the strains. In particular, Tc24 was under strong purifying selection pressure and predicted CD8+ T‐cell epitopes were mostly conserved. Tc24 strong conservation may be associated with structural/functional constrains to preserve EF hand domains and their calcium‐binding loops, and Tc24 is likely important for the parasite fitness. Discussion: Together, these results show that a vaccine based on Tc24 is likely to be effective against a wide diversity of parasite strains across the American continent, and further development of this vaccine candidate should be a high priority. [ABSTRACT FROM AUTHOR]

Concerns about the prospect of a global pandemic have been triggered many times during the last two decades. These have been realised through the current COVID‐19 pandemic, due to a new coronavirus SARS‐CoV2, which has impacted almost every country on Earth. Here, we show how considering the pandemic through the lenses of the evolutionary ecology of pathogens can help better understand the root causes and devise solutions to prevent the emergence of future pandemics. We call for better integration of these approaches into transdisciplinary research and invite scientists working on the evolutionary ecology of pathogens to contribute to a more "solution‐oriented" agenda with practical applications, emulating similar movements in the field of economics in recent decades. [ABSTRACT FROM AUTHOR]

Background: In Mexico, estimates of Chagas disease prevalence and burden vary widely. Updating surveillance data is therefore an important priority to ensure that Chagas disease does not remain a barrier to the development of Mexico's most vulnerable populations. Methodology/Principal findings: The aim of this systematic review and meta-analysis was to analyze the literature on epidemiological surveys to estimate Chagas disease prevalence and burden in Mexico, during the period 2006 to 2017. A total of 2,764 articles were screened and 36 were retained for the final analysis. Epidemiological surveys have been performed in most of Mexico, but with variable study scale and geographic coverage. Based on studies reporting confirmed cases (i.e. using at least 2 serological tests), and taking into account the differences of sample sizes, the national estimated seroprevalence of Trypanosoma cruzi infection was 3.38% [95%CI 2.59–4.16], suggesting that there are 4.06 million cases in Mexico. Studies focused on pregnant women, which may transmit the parasite to their newborn during pregnancy, reported an estimated seroprevalence of 2.21% [95%CI 1.46–2.96], suggesting that there are 50,675 births from T. cruzi infected pregnant women per year, and 3,193 cases of congenitally infected newborns per year. Children under 18 years had an estimated seropositivity rate of 1.51% [95%CI 0.77–2.25], which indicate ongoing transmission. Cases of T. cruzi infection in blood donors have also been reported in most states, with a national estimated seroprevalence of 0.55% [95%CI 0.43–0.66]. Conclusions/Significance: Our analysis suggests a disease burden for T. cruzi infection higher than previously recognized, highlighting the urgency of establishing Chagas disease surveillance and control as a key national public health priority in Mexico, to ensure that it does not remain a major barrier to the economic and social development of the country's most vulnerable populations. [ABSTRACT FROM AUTHOR]

Acquired carbapenemases currently pose one of the most worrying public health threats related to antimicrobial resistance. A NDM-1-producing Salmonella Corvallis was reported in 2013 in a wild raptor. Further research was needed to understand the role of wild birds in the transmission of bacteria resistant to carbapenems. Our aim was to investigate the presence of carbapenem-resistant Escherichia coli in gulls from southern France. In 2012, we collected 158 cloacal swabs samples from two gull species: yellow-legged gulls ( Larus michahellis) that live in close contact with humans and slender-billed gulls ( Chroicocephalus genei) that feed at sea. We molecularly compared the carbapenem-resistant bacteria we isolated through culture on selective media with the carbapenem-susceptible strains sampled from both gull species and from stool samples of humans hospitalized in the study area. The genes coding for carbapenemases were tested by multiplex PCR. We isolated 22 carbapenem-resistant E. coli strains from yellow-legged gulls while none were isolated from slender-billed gulls. All carbapenem-resistant isolates were positive for bla VIM-1 gene. VIM-1-producing E. coli were closely related to carbapenem-susceptible strains isolated from the two gull species but also to human strains. Our results are alarming enough to make it urgently necessary to determine the contamination source of the bacteria we identified. More generally, our work highlights the need to develop more bridges between studies focusing on wildlife and humans in order to improve our knowledge of resistant bacteria transmission routes. [ABSTRACT FROM AUTHOR]

Hosts often accelerate their reproductive effort in response to a parasitic infection, especially when their chances of future reproduction decrease with time from the onset of the infection. Because malignancies usually reduce survival, and hence potentially the fitness, it is expected that hosts with early cancer could have evolved to adjust their life-history traits to maximize their immediate reproductive effort. Despite the potential importance of these plastic responses, little attention has been devoted to explore how cancers influence animal reproduction. Here, we use an experimental setup, a colony of genetically modified flies Drosophila melanogaster which develop colorectal cancer in the anterior gut, to show the role of cancer in altering life-history traits. Specifically, we tested whether females adapt their reproductive strategy in response to harboring cancer. We found that flies with cancer reached the peak period of oviposition significantly earlier (i.e., 2 days) than healthy ones, while no difference in the length and extent of the fecundity peak was observed between the two groups of flies. Such compensatory responses to overcome the fitness-limiting effect of cancer could explain the persistence of inherited cancer-causing mutant alleles in the wild. [ABSTRACT FROM AUTHOR]

The spread of antimicrobial resistance is of major concern for human health and leads to growing economic costs. While it is increasingly hypothesized that wildlife could play an important role in antimicrobial-resistant bacteria dynamics, empirical data remain scarce., The present work builds on a systematic review of the available data in order to highlight the main information we have and to suggest research pathways that should be followed if we aim to fill the gaps in our current knowledge., To achieve this goal, we address four questions: (i) Which resistant bacteria are the most frequently observed in wildlife? (ii) How are resistant bacteria exchanged between wildlife and the other hosts involved? (iii) In which habitats are those resistant bacteria found? (iv) Are resistances associated with certain ecological traits of the host?, Synthesis and applications. We highlight the strong link existing between the impact of human activities on natural habitats and the carriage of antimicrobial-resistant bacteria by wildlife. Furthermore, we underline that omnivorous, anthropophilic and carnivorous species are at high risk of being carriers and potentially spreaders of antimicrobial-resistant bacteria. Identifying among those groups key sentinel species may be of particular interest to implement ecosystem contamination surveillance. Finally, we discuss possible exchange routes for antimicrobial-resistant bacteria between humans and wildlife. Considering that water is of major importance in those exchanges, a critical way to control antimicrobial resistance spread may be to limit aquatic environment contamination by antimicrobial-resistant bacteria and antibiotics. [ABSTRACT FROM AUTHOR]

Avian influenza viruses (AIVs) are of great concern worldwide due to their economic impact and the threat they represent to human health. As wild birds are the natural reservoirs of AIVs, understanding AIV dynamics in different avian taxa is essential for deciphering the epidemiological links between wildlife, poultry and humans. To date, only the Anatidae (ducks, geese and swans) have been widely studied. Here, we aim to shed light on the current state of knowledge on AIVs in Laridae (gulls, terns and kittiwakes) versus that in Anatidae by setting forth four fundamental questions: how, when, where and to which host species are AIVs transmitted? First, we describe ecological differences between Laridae and Anatidae and discuss how they may explain observed contrasts in preferential transmission routes and the evolution of specific AIV subtypes. Second, we highlight the dissimilarities in the temporal patterns of AIV shedding between Laridae and Anatidae and address the role that immunity likely plays in shaping these patterns. Third, we underscore that Laridae may be key in promoting intercontinental exchanges of AIVs. Finally, we emphasize the crucial epidemiological position that Laridae occupy between wildlife, domestic birds and humans. [ABSTRACT FROM AUTHOR]

Background: Carcinogenesis affects not only humans but almost all metazoan species. Understanding the rules driving the occurrence of cancers in the wild is currently expected to provide crucial insights into identifying how some species may have evolved efficient cancer resistance mechanisms. Recently the absence of correlation across species between cancer prevalence and body size (coined as Peto's paradox) has attracted a lot of attention. Indeed, the disparity between this null hypothesis, where every cell is assumed to have an identical probability to undergo malignant transformation, and empirical observations is particularly important to understand, due to the fact that it could facilitate the identification of animal species that are more resistant to carcinogenesis than expected. Moreover it would open up ways to identify the selective pressures that may be involved in cancer resistance. However, Peto's paradox relies on several questionable assumptions, complicating the interpretation of the divergence between expected and observed cancer incidences.Discussions: Here we review and challenge the different hypotheses on which this paradox relies on with the aim of identifying how this null hypothesis could be better estimated in order to provide a standard protocol to study the deviation between theoretical/theoretically predicted and observed cancer incidence. We show that due to the disproportion and restricted nature of available data on animal cancers, applying Peto's hypotheses at species level could result in erroneous conclusions, and actually assume the existence of a paradox. Instead of using species level comparisons, we propose an organ level approach to be a more accurate test of Peto's assumptions.Summary: The accuracy of Peto's paradox assumptions are rarely valid and/or quantifiable, suggesting the need to reconsider the use of Peto's paradox as a null hypothesis in identifying the influence of natural selection on cancer resistance mechanisms. [ABSTRACT FROM AUTHOR]

For an increasing number of biologists, cancer is viewed as a dynamic system governed by evolutionary and ecological principles. Throughout most of human history, cancer was an uncommon cause of death and it is generally accepted that common components of modern culture, including increased physiological stresses and caloric intake, favor cancer development. However, the precise mechanisms for this linkage are not well understood. Here, we examine the roles of ecological and physiological disturbances and resource availability on the emergence of cancer in multicellular organisms. We argue that proliferation of 'profiteering phenotypes' is often an emergent property of disturbed, resource-rich environments at all scales of biological organization. We review the evidence for this phenomenon, explore it within the context of malignancy, and discuss how this ecological framework may offer a theoretical background for novel strategies of cancer prevention. This work provides a compelling argument that the traditional separation between medicine and evolutionary ecology remains a fundamental limitation that needs to be overcome if complex processes, such as oncogenesis, are to be completely understood. [ABSTRACT FROM AUTHOR]

The evolutionary perspective of cancer (which origins and dynamics result from evolutionary processes) has gained significant international recognition over the past decade and generated a wave of enthusiasm among researchers. In this context, several authors proposed that insights into evolutionary and adaptation dynamics of cancers can be gained by studying the evolutionary strategies of organisms. Although this reasoning is fundamentally correct, in our opinion, it contains a potential risk of excessive adaptationism, potentially leading to the suggestion of complex adaptations that are unlikely to evolve among cancerous cells. For example, the ability of recognizing related conspecifics and adjusting accordingly behaviors as in certain free-living species appears unlikely in cancer. Indeed, despite their rapid evolutionary rate, malignant cells are under selective pressures for their altered lifestyle for only few decades. In addition, even though cancer cells can theoretically display highly sophisticated adaptive responses, it would be crucial to determine the frequency of their occurrence in patients with cancer, before therapeutic applications can be considered. Scientists who try to explain oncogenesis will need in the future to critically evaluate the metaphorical comparison of selective processes affecting cancerous cells with those affecting organisms. This approach seems essential for the applications of evolutionary biology to understand the origin of cancers, with prophylactic and therapeutic applications. [ABSTRACT FROM AUTHOR]

Background Olfaction plays a significant role in insect behavior during critical steps of their life-cycle, such as host-seeking during foraging or the search for a mate. Here, we explored genetic polymorphism within and divergence between sibling species of the African malaria mosquito, Anopheles gambiae sensu lato in the gene sequence and encoded peptides of an odorant receptor, Or39. This study included sympatric specimens of An. gambiae sensu stricto, An. coluzzii and An. arabiensis sampled together in the village of Dielmo, Senegal. Results A 1,601 bp genomic sequence composed of 6 exons and 5 introns was obtained for Or39 from 6-8 mosquitoes in each of the 3 species. DNA sequence analysis revealed a high level of molecular polymorphism (p = 0.0154; Haplotype diversity = 0.867) and high overall genetic differentiation between taxa (Fst > 0.92, P < 0.01). In total, 50 parsimony informative sites were recorded. Throughout the whole dataset, there were 13 non-synonymous mutations resulting in aminoacid changes in the encoded protein. Each of the 6 different identified peptides was species-specific and none was shared across species. Most aminoacid changes were located on the intracellular domains of the protein. However, intraspecific polymorphisms in An. gambiae and An. arabiensis as well as species-specific mutations also occurred in the first extracellular domain. Conclusions Although obtained from a limited number of specimens, our results point towards genetic differences between cryptic species within the An. gambiae complex in a gene of biological relevance that might be of evolutionary significance when exposed to disruptive selective forces. [ABSTRACT FROM AUTHOR]

In recent years, a number of zoonotic flaviviruses have emerged worldwide, and wild birds serve as their major reservoirs. Epidemiological surveys of bird populations at various geographical scales can clarify key aspects of the eco-epidemiology of these viruses. In this study, we aimed at exploring the presence of flaviviruses in the western Mediterranean by sampling breeding populations of the yellow-legged gull (Larus michahellis), a widely distributed, anthropophilic, and abundant seabird species. For 3 years, we sampled eggs from 19 breeding colonies in Spain, France, Algeria, and Tunisia. First, ELISAs were used to determine if the eggs contained antibodies against flaviviruses. Second, neutralization assays were used to identify the specific flaviviruses present. Finally, for colonies in which ELISA-positive eggs had been found, chick serum samples and potential vectors, culicid mosquitoes and soft ticks (Ornithodoros maritimus), were collected and analyzed using serology and PCR, respectively. The prevalence of flavivirus-specific antibodies in eggs was highly spatially heterogeneous. In northeastern Spain, on the Medes Islands and in the nearby village of L'Escala, 56% of eggs had antibodies against the flavivirus envelope protein, but were negative for neutralizing antibodies against three common flaviviruses: West Nile, Usutu, and tick-borne encephalitis viruses. Furthermore, little evidence of past flavivirus exposure was obtained for the other colonies. A subset of the Ornithodoros ticks from Medes screened for flaviviral RNA tested positive for a virus whose NS5 gene was 95% similar to that of Meaban virus, a flavivirus previously isolated from ticks of Larus argentatus in western France. All ELISA-positive samples subsequently tested positive for Meaban virus neutralizing antibodies. This study shows that gulls in the western Mediterranean Basin are exposed to a tick-borne Meaban-like virus, which underscores the need of exploring the spatial and temporal distribution of this flavivirus as well as its potential pathogenicity for animals and humans. [ABSTRACT FROM AUTHOR]

In recent years, the number of West Nile virus (WNV) cases reported in horses and humans has increased dramatically throughout the Mediterranean basin. Furthermore, the emergence of Usutu virus (USUV) in Austria in 2001, and its subsequent expansion to Hungary, Spain, Italy, Switzerland, the United Kingdom, and Germany, has given added cause for concern regarding the impact of the spread of flaviviruses on human and animal health in western Europe. Despite frequent detection of WNV and USUV cases in neighboring countries, no case of WNV has been detected in France since 2006 and USUV has never been reported. However, recent investigations focused on detecting the circulation of flaviviruses in France are lacking. We investigated the circulation of WNV and USUV viruses in wild birds in southern France on the basis of a serological survey conducted on a sentinel species, the magpie (Pica pica), in the Camargue area from November, 2009, to December, 2010. We detected WNV-neutralizing antibodies at a high titer (160) in a second-year bird showing recent exposure to WNV, although no WNV case has been detected in humans or in horses since 2004 in the Camargue. In addition, we observed low titers (10 or 20) of USUV-specific antibodies in six magpies, two of which were also seropositive for WNV. Such low titers do not give grounds for concluding that these birds had been exposed to USUV; cross-reactions at low titers may occur between antigenically closely related flaviviruses. But these results urge for further investigations into the circulation of flaviviruses in southern France. They also emphasize the necessity of undertaking epidemiological studies on a long-term basis, rather than over short periods following public health crises, to gain insight into viral dynamics within natural reservoirs. [ABSTRACT FROM AUTHOR]

Female birds transfer antibodies to their offspring via the egg yolk, thus possibly providing passive immunity against infectious diseases to which hatchlings may be exposed, thereby affecting their fitness. It is nonetheless unclear whether the amount of maternal antibodies transmitted into egg yolks varies with female quality and egg laying order. In this paper, we investigated the transfer of maternal antibodies against type A influenza viruses (anti-AIV antibodies) by a long-lived colonial seabird, the yellow-legged gull (Larus michahellis), in relation to fluctuating asymmetry in females, i.e. the random deviation from perfect symmetry in bilaterally symmetric morphological and anatomical traits. In particular, we tested whether females with greater asymmetry transmitted fewer antibodies to their eggs, and whether within-clutch variation in yolk antibodies varied according to the maternal level of fluctuating asymmetry. We found that asymmetric females were in worse physical condition, produced fewer antibodies, and transmitted lower amounts of antibodies to their eggs. We also found that, within a given clutch, yolk antibody level decreased with egg laying order, but this laying order effect was more pronounced in clutches laid by the more asymmetric females. Overall, our results support the hypothesis that maternal quality interacts with egg laying order in determining the amount of maternal antibodies transmitted to the yolks. They also highlight the usefulness of fluctuating asymmetry as a sensitive indicator of female quality and immunocompetence in birds. [ABSTRACT FROM AUTHOR]

Cancer is a major public health issue and represents a significant burden in countries with different levels of economic wealth. In parallel, mosquito-borne infectious diseases represent a growing problem causing significant morbidity and mortality worldwide. Acknowledging that these two concerns are both globally distributed, it is essential to investigate whether they have a reciprocal connection that can fuel their respective burdens. Unfortunately, very few studies have examined the link between these two threats. This review provides an overview of the possible links between mosquitoes, mosquito-borne infectious diseases and cancer. We first focus on the impact of mosquitoes on carcinogenesis in humans including the transmission of oncogenic pathogens through mosquitoes, the immune reactions following mosquito bites, the presence of non-oncogenic mosquito-borne pathogens, and the direct transmission of cancer cells. The second part of this review deals with the direct or indirect consequences of cancer in humans on mosquito behaviour. Thirdly, we discuss the potential impacts that natural cancers in mosquitoes can have on their life history traits and therefore on their vector capacity. Finally, we discuss the most promising research avenues on this topic and the integrative public health strategies that could be envisioned in this context. Unlabelled Image • Cancer is a major public health issue and a significant burden in countries with different levels of economic wealth. • Mosquito-borne infectious diseases represent a growing problem causing significant morbidity and mortality worldwide. • It is essential to investigate the reciprocal connection between these two concerns that can fuel their respective burdens. • Unfortunately, very few studies have examined the link between these two threats. • It is mandatory to investigate these connections to envision new innovative and integrative strategies against both threats. [ABSTRACT FROM AUTHOR]

A dozen specimens of the oribatid mite Archegozetes magnus (Trhypochthoniidae) were collected from the Chagas disease vector Triatoma dimidiata (Hemiptera: Reduviidae), in Teya, Yucatán, Mexico. This is the first report of phoresy by an oribatid mite on a hemipteran. [ABSTRACT FROM AUTHOR]

Hosts often accelerate their reproductive effort in response to a parasitic infection, especially when their chances of future reproduction decrease with time from the onset of the infection. Because malignancies usually reduce survival, and hence potentially the fitness, it is expected that hosts with early cancer could have evolved to adjust their life-history traits to maximize their immediate reproductive effort. Despite the potential importance of these plastic responses, little attention has been devoted to explore how cancers influence animal reproduction. Here, we use an experimental setup, a colony of genetically modified flies Drosophila melanogaster which develop colorectal cancer in the anterior gut, to show the role of cancer in altering life-history traits. Specifically, we tested whether females adapt their reproductive strategy in response to harboring cancer. We found that flies with cancer reached the peak period of oviposition significantly earlier (i.e., 2 days) than healthy ones, while no difference in the length and extent of the fecundity peak was observed between the two groups of flies. Such compensatory responses to overcome the fitness-limiting effect of cancer could explain the persistence of inherited cancer-causing mutant alleles in the wild.

In recent years, the number of West Nile virus (WNV) cases reported in horses and humans has increased dramatically throughout the Mediterranean basin. Furthermore, the emergence of Usutu virus (USUV) in Austria in 2001, and its subsequent expansion to Hungary, Spain, Italy, Switzerland, the United Kingdom, and Germany, has given added cause for concern regarding the impact of the spread of flaviviruses on human and animal health in western Europe. Despite frequent detection of WNV and USUV cases in neighboring countries, no case of WNV has been detected in France since 2006 and USUV has never been reported. However, recent investigations focused on detecting the circulation of flaviviruses in France are lacking. We investigated the circulation of WNV and USUV viruses in wild birds in southern France on the basis of a serological survey conducted on a sentinel species, the magpie (Pica pica), in the Camargue area from November, 2009, to December, 2010. We detected WNV-neutralizing antibodies at a high titer (160) in a second-year bird showing recent exposure to WNV, although no WNV case has been detected in humans or in horses since 2004 in the Camargue. In addition, we observed low titers (10 or 20) of USUV-specific antibodies in six magpies, two of which were also seropositive for WNV. Such low titers do not give grounds for concluding that these birds had been exposed to USUV; cross-reactions at low titers may occur between antigenically closely related flaviviruses. But these results urge for further investigations into the circulation of flaviviruses in southern France. They also emphasize the necessity of undertaking epidemiological studies on a long-term basis, rather than over short periods following public health crises, to gain insight into viral dynamics within natural reservoirs.

Investigating the prevalence of anti-influenza A viruses (AIV) antibodies in wild birds can provide important information for the understanding of bird exposure to AIV, as well as for prevention purposes. We investigated AIV exposure in nature by measuring the prevalence of anti-AIV antibodies in the nests and adults of an abundant and anthropophilic waterbird species common around the Mediterranean sea, the yellow-legged gull (Larus michahellis). Sampling took place in two colonies located in the gulf of Gabès in southern Tunisia: Sfax and Djerba. Antibodies were detected in the two sites, with higher prevalence in adults, eggs, and nests at Sfax than Djerba. Across both colonies, clutches that were laid later in the season, and, thus, more likely by younger parents, showed lower prevalence. Using patch occupancy modeling applied to egg clutches, we found that it is unnecessary to sample all the eggs in a given nest; nest status (antibody positive or negative) can be reliably estimated from a single egg. Differences in the density of birds, notably Larids, between the two sites may explain the observed differences in prevalence. The higher concentration of Larids in the Sfax colony could favor the transmission of AIV to yellow-legged gulls. This study highlights the importance of further developing ecological-based approaches to the factors determining the circulation of infectious agents in species such as the yellow-legged gull, which exist at the interface between diverse biological communities and human activities.