Mammalian Species Research Articles

Detection of clade 2.3.4.4b highly pathogenic H5N1 influenza virus in New York City.

Highly pathogenic avian influenza viruses of the H5N1 clade 2.3.4.4b were detected in North America in the winter of 2021/2022. These viruses have spread across the Americas, causing morbidity and mortality in both wild and domestic birds as well as some mammalian species, including cattle. Many surveillance programs for wildlife as well as commercial poultry operations have detected these viruses. In this study, we conducted surveillance of avian species in the urban environment in New York City. We detected highly pathogenic H5N1 viruses in six samples from four different bird species and performed whole-genome sequencing. Sequencing analysis showed the presence of multiple different genotypes. Our work highlights that the interface between animals and humans that may give rise to zoonotic infections or even pandemics is not limited to rural environments and commercial poultry operations but extends into the heart of our urban centers.IMPORTANCEWhile surveillance programs for avian influenza viruses are often focused on migratory routes and their associated stop-over locations or commercial poultry operations, many bird species-including migratory birds-frequent or live in urban green spaces and wetlands. This brings them into contact with a highly dense population of humans and pets, providing an extensive urban animal-human interface in which the general public may have little awareness of circulating infectious diseases. This study focuses on virus surveillance of this interface, combined with culturally responsive science education and community outreach.

Steppe lemmings and Chinese hamsters as new potential animal models for the study of the Leishmania subgenus Mundinia (Kinetoplastida: Trypanosomatidae).

Leishmania, the dixenous trypanosomatid parasites, are the causative agents of leishmaniasis currently divided into four subgenera: Leishmania, Viannia, Sauroleishmania, and the recently described Mundinia, consisting of six species distributed sporadically all over the world infecting humans and/or animals. These parasites infect various mammalian species and also cause serious human diseases, but their reservoirs are unknown. Thus, adequate laboratory models are needed to enable proper research of Mundinia parasites. In this complex study, we compared experimental infections of five Mundinia species (L. enriettii, L. macropodum, L. chancei, L. orientalis, and four strains of L. martiniquensis) in three rodent species: BALB/c mouse, Chinese hamster (Cricetulus griseus) and steppe lemming (Lagurus lagurus). Culture-derived parasites were inoculated intradermally into the ear pinnae and progress of infection was monitored for 20 weeks, when the tissues and organs of animals were screened for the presence and quantity of Leishmania. Xenodiagnoses with Phlebotomus duboscqi were performed at weeks 5, 10, 15 and 20 post-infection to test the infectiousness of the animals throughout the experiment. BALB/c mice showed no signs of infection and were not infectious to sand flies, while Chinese hamsters and steppe lemmings proved susceptible to all five species of Mundinia tested, showing a wide spectrum of disease signs ranging from asymptomatic to visceral. Mundinia induced significantly higher infection rates in steppe lemmings compared to Chinese hamsters, and consequently steppe lemmings were more infectious to sand flies: In all groups tested, they were infectious from the 5th to the 20th week post infection. In conclusion, we identified two rodent species, Chinese hamster (Cricetulus griseus) and steppe lemming (Lagurus lagurus), as candidates for laboratory models for Mundinia allowing detailed studies of these enigmatic parasites. Furthermore, the long-term survival of all Mundinia species in steppe lemmings and their infectiousness to vectors support the hypothesis that some rodents have the potential to serve as reservoir hosts for Mundinia.

Coevolution of Non-Homologous End Joining efficiency and encephalization.

Double strand breaks, the most difficult to repair DNA damage, are mainly repaired by Non-Homologous End-Joining (NHEJ) or Homologous Recombination (HR). Previous studies seem to indicate that primates, and particularly humans, have a better NHEJ system. A distinctive feature of the primate lineage (beside longevity) is encephalization, i.e. the expansion of brain relative to body mass. Using existing transcriptome data from 34 mammalian species, we investigated the possible correlations between the expression of genes involved in NHEJ and encephalization, body mass and longevity. The same was done also for genes involved in the HR pathway. We found that, while HR gene expression is better correlated with longevity, NHEJ gene expression is strongly (and better) correlated with encephalization. Since the brain is composed of post-mitotic cells, double-strand breaks repair should be mainly performed by NHEJ in this organ. Therefore, we interpret the correlation we found as an indication that NHEJ efficiency coevolved with encephalization.

Molecular Detection and Characterization of Hemotropic Mycoplasma in Assamese Macaques (Macaca assamensis) of Northern Thailand

Hemotropic mycoplasmas, also known as hemoplasmas, are parasitic bacteria that infect red blood cells, potentially leading to varying degrees of anemia across numerous mammalian species, including nonhuman primates. The present study aims to investigate the prevalence of hemoplasma infection and identify the species involved among free-ranging Assamese macaques (Macaca assamensis) inhabiting northern Thailand. A total of 133 blood samples were collected from Assamese macaques in Chiang Rai province, Thailand, and subjected to screening for hemoplasma infection utilizing nested PCR amplification targeting the 16S rRNA gene. Positive samples were subsequently analyzed through nucleotide sequencing and phylogenetic analysis for putative species identification. Current study results revealed that 17.3% (23/133; 95% CI 11.29-24.81) of Assamese macaques tested positive for hemoplasma infection using the nested PCR assay. Partial 16S rRNA sequences derived from hemoplasma isolates in Assamese macaques exhibited 99% homology, forming a cluster within the same phylogenetic clade as “Candidatus Mycoplasma haematomacacae,” previously identified in long-tailed macaques, rhesus macaques, and Japanese macaques. These findings suggest the presence of “Ca. M. haematomacacae” not only in long-tailed macaques and rhesus macaques but also in Assamese macaques in Thailand. To our knowledge, this marks the first molecular detection of “Ca. M. haematomacacae” in Assamese macaques in Thailand. These results hold significance as they enhance our understanding of hemoplasma infection distribution among macaque populations in Thailand.

Extralimital terrestrials: A reassessment of range limits in Alaska's land mammals.

Understanding and mitigating the effects of anthropogenic climate change on species distributions requires the ability to track range shifts over time. This is particularly true for species occupying high-latitude regions, which are experiencing more extreme climate change than the rest of the world. In North America, the geographic ranges of many mammals reach their northernmost extent in Alaska, positioning this region at the leading edge of climate-induced distribution change. Over a decade has elapsed since the publication of the last spatial assessments of terrestrial mammals in the state. We compared public occurrence records against commonly referenced range maps to evaluate potential extralimital records and develop repeatable baseline range maps. We compared occurrence records from the Global Biodiversity Information Facility for 61 terrestrial mammal species native to mainland Alaska against a variety of range estimates (International Union for Conservation of Nature, Alaska Gap Analysis Project, and the published literature). We mapped extralimital records and calculated proportions of occurrences encompassed by range extents, measured mean direction and distance to prior range margins, evaluated predictive accuracy of published species models, and highlighted observations on federal lands in Alaska. Range comparisons identified 6,848 extralimital records for 39 of 61 (63.9%) terrestrial mainland Alaskan species. On average, 95.5% of Alaska Gap Analysis Project occurrence records and ranges were deemed accurate (i.e., > 90.0% correct) for 31 of 37 species, but overestimated extents for 13 species. The International Union for Conservation of Nature range maps encompassed 68.1% of occurrence records and were > 90% accurate for 17 of 39 species. Extralimital records represent either improved sampling and digitization or actual geographic range expansions. Here we provide new data-driven range maps, update standards for the archiving of museum-quality locational records and offer recommendations for mapping range changes for monitoring and conservation.

Explorational analysis of the abundance and prevalence of chigger and gamasid mites parasitic on small mammals in Vietnam.

We studied chigger and gamasid mite loads on small mammals during the dry season in Vietnam and used both our field data and museum collections to estimate the influence of environmental factors on mite abundance and prevalence. Generalized linear (mixed effect) models were used to analyze the data. We examined 1,239 small mammal individuals, which were obtained from field expeditions and museum collections belonging to 59 species. In different localities, Rattus Fischer(Rodentia: Muridae), Niviventer Marshall(Rodentia: Muridae), and Maxomys Sody (Rodentia: Muridae) were the most common animals captured. The prevalence of chigger and gamasid mites in our expedition data was high: 72% and 62%, respectively. We found differences in the abundance of chigger mites between different populations of the same species of small mammals. Season and locality were the main factors that influenced chigger mite abundance and prevalence. The best model that predicted the abundance and prevalence of chigger mites included geography (province) as a predictor and host species and season as random effects. For the first time, we analyzed factors connected with climate and weather affecting chigger mites of small mammals in Vietnam.

Ultrasonic vocalisation rate tracks the diurnal pattern of activity in winter phenotype Djungarian hamsters (Phodopus sungorus).

Vocalisations are increasingly being recognised as an important aspect of normal rodent behaviour yet little is known of how they interact with other spontaneous behaviours such as sleep and torpor, particularly in a social setting. We obtained chronic recordings of the vocal behaviour of adult male and female Djungarian hamsters (Phodopus sungorus) housed under short photoperiod (8h light, 16h dark, square wave transitions), in different social contexts. The animals were kept in isolation or in same-sex sibling pairs, separated by a grid which allowed non-physical social interaction. On approximately 20% of days hamsters spontaneously entered torpor, a state of metabolic depression that coincides with the rest phase of many small mammal species in response to actual or predicted energy shortages. Animals produced ultrasonic vocalisations (USVs) with a peak frequency of 57kHz in both social and asocial conditions and there was a high degree of variability in vocalisation rate between subjects. Vocalisation rate was correlated with locomotor activity across the 24-h light cycle, occurring more frequently during the dark period when the hamsters were more active and peaking around light transitions. Solitary-housed animals did not vocalise whilst torpid and animals remained in torpor despite overlapping with vocalisations in social-housing. Besides a minor decrease in peak USV frequency when isolated hamsters were re-paired with their siblings, changing social contexts did not influence vocalisation behaviour or structure. In rare instances, temporally overlapping USVs occurred when animals were socially-housed and were grouped in such a way that could indicate coordination. We did not observe broadband calls (BBCs) contemporaneous with USVs in this paradigm, corroborating their correlation with physical aggression which was absent from our experiment. Overall, we find little evidence to suggest a direct social function of hamster USVs. We conclude that understanding the effects of vocalisations on spontaneous behaviours, such as sleep and torpor, will inform experimental design of future studies, especially where the role of social interactions is investigated.

Mammalian and avian species quantification in homogenized foods: real time PCR and digital PCR as tools for label compliance controls

Currently food fraud and authenticity of products composition are topics of great concern; ingredients quantification could allow to identify small amounts of contaminats or voluntary addition of improper components. Many molecular methods are available for species identification in foodstuffs but, for a better application, they should not be affected by the interference of other ingredients. The main purpose of this work was to verify the Real Time PCR and the Digital PCR (dPCR) quantification performances on baby food samples, specifically selected for their high miscibility to limit variability; chicken was selected as target to verify the performance of quantification of methods after having spiked the same quantity in different baby foods. The other aims were: (1) to verify a constant genome copies ratio existence between mammalian and avian species (2) to verify the dPCR performance, set up on housekeeping, to quantify mammalian and avian species in commercial products. Digital PCR showed fewer differences respect to Real Time PCR, at the same 15% w/w chicken spiking level. Despite the constant difference between mammalian and avian genome copies, in samples with the same spiking weight, the confidence intervals increasing towards the extreme values, made impossible to use genome copies ratio as a sort of correction factor between species. Finally, the dPCR system using the myostatin housekeeping gene to determine the chicken content seemed reliable to verify the labelling compliance in meat-based commercial products.

MeCP2 binds to methylated DNA independently of phase separation and heterochromatin organisation

Correlative evidence has suggested that the methyl-CpG-binding protein MeCP2 contributes to the formation of heterochromatin condensates via liquid-liquid phase separation. This interpretation has been reinforced by the observation that heterochromatin, DNA methylation and MeCP2 co-localise within prominent foci in mouse cells. The findings presented here revise this view. MeCP2 localisation is independent of heterochromatin as MeCP2 foci persist even when heterochromatin organisation is disrupted. Additionally, MeCP2 foci fail to show hallmarks of phase separation in live cells. Importantly, we find that mouse cellular models are highly atypical as MeCP2 distribution is diffuse in most mammalian species, including humans. Notably, MeCP2 foci are absent in Mus spretus which is a mouse subspecies lacking methylated satellite DNA repeats. We conclude that MeCP2 has no intrinsic tendency to form condensates and its localisation is independent of heterochromatin. Instead, the distribution of MeCP2 in the nucleus is primarily determined by global DNA methylation patterns.

Pigs are highly susceptible to but do not transmit mink-derived highly pathogenic avian influenza virus H5N1 clade 2.3.4.4b

Rapid evolution of highly pathogenic avian influenza viruses (HPAIVs) is driven by antigenic drift but also by reassortment, which might result in robust replication in and transmission to mammals. Recently, spillover of clade 2.3.4.4b HPAIV to mammals including humans, and their transmission between mammal species has been reported. This study aimed to evaluate the pathogenicity and transmissibility of a mink-derived clade 2.3.4.4b H5N1 HPAIV isolate from Spain in pigs. Experimental infection caused interstitial pneumonia with necrotizing bronchiolitis with high titers of virus present in the lower respiratory tract and 100% seroconversion. Infected pigs shed limited amount of virus, and importantly, there was no transmission to contact pigs. Notably, critical mammalian-like mutations such as PB2-E627K and HA-Q222L emerged at low frequencies in principal-infected pigs. It is concluded that pigs are highly susceptible to infection with the mink-derived clade 2.3.4.4b H5N1 HPAIV and provide a favorable environment for HPAIV to acquire mammalian-like adaptations.

Systemic toxoplasmosis in 2 domestic rabbits in Georgia, United States.

Toxoplasma gondii infections are common in a range of mammalian and avian species, but clinical disease has been reported only rarely in domestic rabbits. Two cases of toxoplasmosis in domestic rabbits from the same premises were submitted to a diagnostic pathology facility in Athens, GA, USA. Both rabbits died after exhibiting clinical signs of gastrointestinal stasis. The gross findings observed in both rabbits comprised miliary, random, white-to-tan, necrotic foci throughout the spleen, liver, and lungs. Histologically, tachyzoites were observed within necrotizing inflammatory foci in the spleens of both rabbits, and in various other organs (tracheobronchial lymph node, lung, heart, and cecal appendix) of one rabbit. In both cases, the tachyzoites were immunoreactive with anti-Toxoplasma gondii antibodies. In addition, T. gondii DNA was detected via PCR and sequencing from a fresh lung sample from one rabbit and formalin-fixed, paraffin-embedded spleen, liver, femoral bone marrow, and haired skin from the second rabbit. Given that T. gondii can cause disease in domestic rabbits and is also a concern for other potential intermediate hosts (e.g., humans, other domestic animals), this parasite warrants consideration in the diagnostic evaluation of lagomorph tissues with compatible lesions.

RE: Expert range maps of global mammal distributions harmonised to three taxonomic authorities

Abstract In a recent paper titled Expert range maps of global mammal distributions harmonised to three taxonomic authorities, Marsh et al. (2022) introduced a series of new geographic range maps for all extant species of mammals and made these maps available on the Map of Life (MoL) website (www.mol.org). The title of the paper and inclusion of over 140 prominent mammalogists and biogeographers as coauthors strongly suggested that these new range maps were carefully vetted. However, when examining the maps of Marsh et al. (2022) on the MoL web platform, we found a variety of serious problems, including, but not limited to: range exaggerations (inclusion of substantial geographic areas not represented by specimen records or verified observations); range maps that are geographically shifted so that species are shown as occurring in areas in which they do not, and not occurring in areas in which they do (and in some cases, these new maps do not even encompass the type locality of a species); range maps that simply omit peripheral populations of conservation concern; and range maps for fully marine mammals (i.e., those that do not spend any time on land) that include large swaths of both insular and continental landmasses. Overall, we evaluated the new “expert” mammal range maps on the MoL platform for 78 species (retrieved between 31 March 2022 and 1 April 2023) and show that there are serious, systemic problems with these maps, and that these problems are both geographically and taxonomically widespread. As such, we caution researchers to carefully review and evaluate the range maps of Marsh et al. (2022) on the MoL before using them for any research purpose—including conservation, biogeographical, and macroecological analyses of mammals.

Review of the distribution and biology of the snake mite Ophionyssus natricis (Acari: Macronyssidae)

The mite Ophionyssus natricis (Gervais, 1844) (Macronyssidae) is a widespread ectoparasite of reptiles and a vector of some important veterinary diseases. This paper reviews the geographic distribution and host range of O. natricis and the available information about its clinical significance. Some incorrect identifications and host records are also identified. The snake mite has been collected from 144 species of reptiles, mostly snakes, as well as one amphibian and three species of mammals. It has been recorded in 36 countries in Europe, Asia, Africa, North and South America, and Australia. Its geographic range has undoubtedly been extended by human activities. Our records of O. natricis on the lizards Darevskia brauneri (Méhely, 1909) and Ophisops elegans Ménétries 1832, and on the snake Telescopus fallax Fleischmann, 1831, are new host records.

Energetic cost of biosynthesis is a missing link between growth and longevity in mammals

The comparative studies of aging have established a negative correlation between Gompertz postnatal growth constant and maximum lifespan across mammalian species, but the underlying physiological mechanism remains unclear. This study shows that the Gompertz growth constant can be decomposed into two energetic components, mass-specific metabolic rate and the energetic cost of biosynthesis, and that after controlling the former as a confounder, the negative correlation between growth constant and lifespan still exists due to a 100-fold variation in the latter, revealing that the energetic cost of biosynthesis is a link between growth and longevity in mammals. Previously, the energetic cost of biosynthesis has been thought to be a constant across species and therefore was not considered a contributor to the variation in any life history traits, such as growth and lifespan. This study employs a recently proposed model based on energy conservation to explain the physiological effect of the variation in this energetic cost on the aging process and illustrates its role in linking growth and lifespan. The conventional life history theory suggested a tradeoff between growth and somatic maintenance, but the findings in this study suggest that allocating more energy to biosynthesis may enhance the somatic maintenance and extend lifespan and, hence, reveal a more complex nature of the tradeoff.

Multi-Scale Analysis of Lyme Disease Ecology

Multi-Scale Analysis of Lyme Disease Ecology

Relationships between Anthropogenic Activities and Distribution of Medium to Large Mammal Species Assemblage in Madi Wildlife Corridor: Implication for Biodiversity Conservation in Uganda

Wildlife corridors between protected areas increase connectivity by integrating populations into single demographic units, thereby increasing gene flows within populations and thus probability of survival. This study assessed the relationship between anthropogenic activities and mammal species assemblage within and around Madi wildlife corridor. The study adopted recce walks along a zig-zag line transect and straight line transect methods of game tracking. Global Position System (GPS) was used to map locations of direct mammal sightings, vocalizations, tracks, dung/droppings, diggings, carcasses, and skeletal remains of mammal species. Similarly, anthropogenic activities such as hunting using bow and arrows, rifles, trapping, tree cutting, charcoal burning, bush burning, cultivation, and settlements that seemed to influence assemblage of the mammals in the area of study were mapped. The result showed that the Madi wildlife corridor still contained diverse mammal species including but not limited to; the African Elephants (Loxodonta Africana sp.), Buffaloes (Syncerus caffer) Leopards (Panthera pardus), Spotted Hyena (Crocuta Crocuta), Northern Giraffe (Giraffa Camelopardalis), Uganda kob (Kobus kob thomasi), Hartebeest (Alcelaphus buselaphus) and Reedbuck (Redunca arundinum), which were comparable to that of the adjacent Murchison Falls National Park (MFNP). The relationship between anthropogenic activities and species assemblage showed a negatively skewed distribution of some of the large mammal species specifically Elephants, Giraffes, and Hippopotamus. The study recommends gazettement of a wildlife corridor between MFNP and East Madi Wildlife Reserve to promote wildlife connectivity between two adjacent ecosystem-protected areas in northern Uganda. As a long-term strategy for wildlife conservation, it is crucial to undertake a systematic assessment and prioritization and demarcation of wildlife corridors and development of a comprehensive action plan for securing them. We further recommend development of a national Wildlife Corridor Regulations to provide a framework for the sustainable conservation of biodiversity

PSIII-8 Expression of Toll-Like Receptors in endometrium of gilts during early gestation

Abstract Interactions between the innate immune system and reproductive tissues via Toll-like receptors (TLRs) have a pivotal role in maintaining the health and fertility status of mammalian species. TLRs are pattern recognition receptors used by the innate immune system to regulate inflammation, infections, and to indicate the presence of pathogenic activity within a tissue. Recent studies have identified several TLRs present in pigs that can detect a variety of molecules. Previous data from our group has demonstrated shifts in bacterial communities within the uterus during early gestation in gilts. Therefore, the objective of this study was to quantify and compare expression of TLR1, TLR2, TLR4, TLR5, and TLR6 in endometria of gilts. These TLRs were chosen because they are located on the cell surface and recognize invading microbes. Crossbred gilts (n = 21) free of physical, health or reproductive-related issues were euthanized and hysterectomized during the preimplantation (d 11) and peri-implantation (d 15) stages of pregnancy (Pregnant d 11, n = 10; Pregnant d 15, n = 11). Samples of endometrial mucosa were collected and snap-frozen in sterile 1.5 mL tubes and stored at -80°C until analyzed. The mean relative expression of TLR-1, TLR-2, TLR-4, TLR-5, and TLR-6 mRNAs were quantified by RT-qPCR. Statistical analysis was completed using one-way ANOVA and student’s t-test for pairwise comparison in JMP 17.0 (SAS Institute; Cary, NC). All TLRs were expressed in the endometrium. Expression of TLR-4 was greater on d 11 than d 15 (1.39 ± 0.14 vs. 0.45 ± 0.13, respectively; P < 0.01), and there was a trend for expression of TLR-2 to be greater on d 11 than d 15 (1.89 ± 0.37 vs. 0.90 ± 0.35, respectively; 0.05 < P < 0.1). Expression of TLR2, TLR5, and TLR6 did not differ between d 11 and d 15 (P > 0.05). The results indicate that TLRs are not only expressed in the porcine endometrium, but they differ in expression during early gestation. Conceptus signaling and inflammation during elongation and implantation and/ or shifts in bacterial communities within the uterus may be responsible. Additionally, future work examining bacterial shifts and TLR expression during mid and late gestation may offer further insight.

Bridging Cree knowledge and Western science to understand the decline in hunting success of migratory Canada geese

AbstractCanada goose (Branta canadensis) is one of the main waterfowl species harvested by Cree hunters in James Bay, Canada. Land users who hunt geese along coastal Eeyou Istchee (Eastern James Bay, Quebec) report that they are now much less successful in harvesting sub-arctic breeding geese (B. c. interior) than in the 1980s, especially during the fall hunting season. We followed a mixed-methods triangulation design in which we simultaneously gathered Indigenous and scientific knowledge. For the Indigenous knowledge, we conducted semi-structured interviews with Cree land users who shared their knowledge about how the goose populations that stage in Eeyou Istchee have changed within living memory. They attributed their reduced hunting success to fewer migrating geese and modification of their behavior. They also identified many environmental changes, especially the decline of eelgrass (Zostera marina), that may have affected the number, distribution, and migration patterns of Canada geese along the coastal Eeyou Istchee in the past 50 years. We complemented this information using waterfowl study techniques including aerial surveys, band recovery analyses, and GPS tracking of individually marked geese. Habitat changes both at the local scale in Eeyou Istchee and in other parts of the staging and wintering ranges of Canada geese, natural and human disturbances along the coast, and a gradual increase in molt migrant temperate breeding Canada geese (B. c. maxima) likely resulted in changes in habitat use and migration patterns of sub-arctic breeding Canada geese along the James Bay east coast. By bridging Cree knowledge and Western science, we identified the various factors that affect the harvest success of Eeyou Istchee goose hunters. Such an approach should be encouraged when Indigenous peoples rely upon migratory bird or mammal species that spend only a portion of their annual cycle within the hunting territories of land users.

Male chicks play more than females – sex differences in chicken play ontogeny

Play indicates positive affective states and can therefore potentially be used as an indicator of positive welfare. Sex differences in play has been reported in many mammalian species, but in birds, this is still to be explored. It is known that young chickens perform play behavior during their early ontogeny, but potential sex differences have not previously been addressed. Therefore, we aimed to investigate potential sex effects on play ontogeny in young chickens, by comparing play occurrence in young males and females of a commercial hybrid of White Leghorn. Eighteen chicks of each sex were hatched in the same incubator and then housed in sex-separated groups. Six groups of three chicks each were randomly created for each sex, and the same three chicks were then moved to enriched play arenas twice per week, from day 6 until day 53 post hatch. The frequency of different play behaviors, categorized as locomotor play, social play and object play were recorded during 30 min on each observation day. Each group of three birds constituted the independent statistical replicate. Males played significantly more than females, due to more social and object play, whereas for locomotor play, no difference was found between the sexes. In conclusion, clear sex differences in play in chickens was demonstrated, and this may be linked to the highly sexually dimorphic behavior of adult cockerels and hens. Further research is needed to elucidate the relationships between type and frequency of play in chicks and later behavior as adults.

Highly Pathogenic Avian Influenza (HPAI) H5 Clade 2.3.4.4b Virus Infection in Birds and Mammals.

Avian influenza viruses (AIVs) are highly contagious respiratory viruses of birds, leading to significant morbidity and mortality globally and causing substantial economic losses to the poultry industry and agriculture. Since their first isolation in 2013-2014, the Asian-origin H5 highly pathogenic avian influenza viruses (HPAI) of clade 2.3.4.4b have undergone unprecedented evolution and reassortment of internal gene segments. In just a few years, it supplanted other AIV clades, and now it is widespread in the wild migratory waterfowl, spreading to Asia, Europe, Africa, and the Americas. Wild waterfowl, the natural reservoir of LPAIVs and generally more resistant to the disease, also manifested high morbidity and mortality with HPAIV clade 2.3.4.4b. This clade also caused overt clinical signs and mass mortality in a variety of avian and mammalian species never reported before, such as raptors, seabirds, sealions, foxes, and others. Most notably, the recent outbreaks in dairy cattle were associated with the emergence of a few critical mutations related to mammalian adaptation, raising concerns about the possibility of jumping species and acquisition of sustained human-to-human transmission. The main clinical signs and anatomopathological findings associated with clade 2.3.4.4b virus infection in birds and non-human mammals are hereby summarized.