Isolation and Characterization of Escherichia coli from Brazilian Broilers.

Avian pathogenic Escherichia coli (APEC) causes colibacillosis, one of the main diseases leading to economic losses in industrial poultry farming due to high morbidity and mortality and its role in the condemnation of chicken carcasses. This study aimed to isolate and characterize APEC obtained from necropsied chickens on Brazilian poultry farms. Samples from birds already necropsied by routine inspection were collected from 100 batches of broiler chickens from six Brazilian states between August and November 2021. Three femurs were collected per batch, and characteristic E. coli colonies were isolated on MacConkey agar and characterized by qualitative PCR for minimal predictive APEC genes, antimicrobial susceptibility testing, and whole genome sequencing to identify species, serogroups, virulence genes, and resistance genes. Phenotypic resistance indices revealed significant resistance to several antibiotics from different antimicrobial classes. The isolates harbored virulence genes linked to APEC pathogenicity, including adhesion, iron acquisition, serum resistance, and toxins. Aminoglycoside resistance genes were detected in 79.36% of isolates, 74.6% had sulfonamide resistance genes, 63.49% showed ß-lactam resistance genes, and 49.2% possessed at least one tetracycline resistance gene. This study found a 58% prevalence of avian pathogenic E. coli in Brazilian poultry, with strains showing notable antimicrobial resistance to commonly used antibiotics.

Highly pathogenic avian influenza A (H5N1) virus outbreak in Peru in 2022-2023.

Background: An epizootic of highly pathogenic avian influenza A (H5N1) has spread worldwide since 2022. Even though this virus has been extensively studied for many decades, little is known about its evolution in South America. Methods: Here, we describe the sequencing and characterization of 13 H5N1 genomes collected from wild birds, poultry, and wild mammals in Peru during the genomic surveillance of this outbreak. Results: The samples belonged to the highly pathogenic avian influenza (H5N1) 2.3.4.4b clade. Chilean and Peruvian samples clustered in the same group and therefore share a common ancestor. An analysis of the hemagglutinin and neuraminidase genes detected new mutations, some dependent upon the host type. Conclusions: The genomic surveillance of highly pathogenic avian influenza is necessary to promote the One Health policy and to overcome the new problems entailed by climate change, which may alter the habitats of resident and migratory birds.

Mortality in sea lions is associated with the introduction of the H5N1 clade 2.3.4.4b virus in Brazil October 2023: whole genome sequencing and phylogenetic analysis.

Clade 2.3.4.4b highly pathogenic avian influenza (HPAI) H5N1 virus was detected in the South American sea lions found dead in Santa Catarina, Brazil, in October 2023. Whole genome sequencing and comparative phylogenetic analysis were conducted to investigate the origin, genetic diversity, and zoonotic potentials of the H5N1 viruses. The H5N1 viruses belonged to the genotype B3.2 of clade 2.3.4.4b H5N1 virus, which was identified in North America and disseminated to South America. They have acquired new amino acid substitutions related to mammalian host affinity. Our study provides insights into the genetic landscape of HPAI H5N1 viruses in Brazil, highlighting the continuous evolutionary processes contributing to their possible adaptation to mammalian hosts.

Prevalence and composition of haemosporidians in an avian community from a World Heritage area: Associations with host foraging strata and forest regeneration.

Forest regeneration is becoming a powerful tool to combat land conversion which covers 30 % of the Neotropical territory. However, little is known about the effect of forest regeneration on vector-borne diseases. Here, we describe the haemosporidian lineage composition across a successional gradient within an Atlantic Forest bird community. We test whether forest successional stages, in addition to host life history traits affect haemosporidian infection probability. We sampled birds at 16 sampling units with different successional stages between 2017 and 2018 within a forest remnant located in Antonina, Paraná, Brazil. We captured bird individuals using mist-nets, identified them to the species level, and collected blood samples to detect and identify Plasmodium and Haemoproteus lineages based on molecular analysis. We used a Bayesian phylogenetic linear model with a Bernoulli distribution to test whether the haemosporidian infection probability is affected by nest type, foraging stratum, and forest successional stage. We captured 322 bird individuals belonging to 52 species and 21 families. We found 31 parasite lineages and an overall haemosporidian prevalence of 23.9 %, with most infections being caused by Plasmodium (21.7 % of prevalence). The Plasmodium probability of infection was associated with forest successional stage and bird foraging stratum. Birds from the secondary forest in an intermediate stage of succession are more likely to be infected by the parasites than birds from the primary forests (ß = 1.21, 95 % CI = 0.11 - 2.43), birds from upper strata exhibit a lower probability of infection than birds from lower foraging strata (ß = -1.81, 95 % CI = -3.80 - -0.08). Nest type did not affect the Plasmodium probability of infection. Our results highlight the relevance of forest succession on haemosporidian infection dynamics, which is particularly relevant in a world where natural regeneration is the main tool used in forest restoration.

Phylodynamics of avian influenza A(H5N1) viruses from outbreaks in Brazil.

Our study identified strains of the A/H5N1 virus in analyzed samples of subsistence poultry, wild birds, and mammals, belonging to clade 2.3.4.4b, genotype B3.2, with very high genetic similarity to strains from Chile, Uruguay, and Argentina. This suggests a migratory route for wild birds across the Pacific, explaining the phylogenetic relatedness. The Brazilian samples displayed similarity to strains that had already been previously detected in South America. Phylogeographic analysis suggests transmission of US viruses from Europe and Asia, co-circulating with other lineages in the American continent. As mutations can influence virulence and host specificity, genomic surveillance is essential to detect those changes, especially in critical regions, such as hot spots in the HA, NA, and PB2 sequences. Mutations in the PB2 gene (D701N and Q591K) associated with adaptation and transmission in mammals were detected suggesting a potential zoonotic risk. Nonetheless, resistance to neuraminidase inhibitors (NAIs) was not identified, however, continued surveillance is crucial to detect potential resistance. Our study also mapped the spread of the virus in the Southern hemisphere, identifying possible entry routes and highlighting the importance of surveillance to prevent outbreaks and protect both human and animal populations.

Highly pathogenic avian influenza A(H5N1) in animals: A systematic review and meta-analysis.

Introduction: Avian influenza A H5N1 is a significant global public health threat. Although relevant, systematic reviews about its prevalence in animals are lacking. Methods: We performed a systematic literature review in bibliographic databases to assess the prevalence of H5N1 in animals. A meta-analysis with a random-effects model was performed to calculate the pooled prevalence and 95 % confidence intervals (95%CI). In addition, measures of heterogeneity (Cochran's Q statistic and I2 test) were reported. Results: The literature search yielded 1359 articles, of which 33 studies were fully valid for analysis, including 96,909 animals. The pooled prevalence for H5N1 in birds (n = 90,045, 24 studies) was 5.0 % (95%CI: 4.0-6.0 %; I2 = 99.21); in pigs (n = 3,178, 4 studies) was 1.0 % (95%CI: 0.0-1.0 %); in cats (n = 2,911, 4 studies) was 0.0 % (95%CI: 0.0-1.0 %); and in dogs (n = 479, 3 studies) was 0.0 % (95%CI: 0.0-2.0 %). Conclusions: While the occurrence of H5N1 in animals might be comparatively limited compared to other influenza viruses, its impact on public health can be substantial when it transmits to humans. This virus can potentially induce severe illness and has been linked to previous outbreaks. Therefore, it is essential to closely monitor and comprehend the factors influencing the prevalence of H5N1 in both avian and human populations to develop effective disease control and prevention strategies.

Ocular diagnostics, ophthalmic findings, and conjunctival microbiome in the Chilean flamingo (Phoenicopterus chilensis).

OBJECTIVE: To establish normative data for selected ocular diagnostic tests and commensal conjunctival microflora and describe the incidence of ocular pathology in Chilean flamingos. ANIMALS STUDIED: A total of 41 Chilean flamingos were examined at the Blank Park Zoo in Des Moines, Iowa. PROCEDURES: In 20 flamingos, blink rate was assessed undisturbed in their exhibit, then gentle manual restraint was used to assess palpebral fissure length (PFL), aqueous tear production (phenol red thread test [PRTT] in one eye, endodontic absorbent paper point tear test [EAPPTT] in the other), intraocular pressure (IOP; rebound tonometry), and fluorescein staining. Twenty-one other flamingos were brought to a darkened area for neuro-ophthalmic examination, slit lamp biomicroscopy, and indirect ophthalmoscopy. Swabs from seven flamingos were used for ocular microbiome evaluation. RESULTS: Results are presented as mean ± standard deviation (range). Flamingos comprised 23 females/18 males, aged 11 ± 9.1 (0.7-40) years. Test results: blink rate, 3.7 ± 2 (1-9) blinks/min; PFL, 11.2 ± 1.2 (9-14) mm; IOP, 14 ± 3.2 (10-22) mmHg; EAPPT, 10.2 ± 2.8 (9-14) mm/min; PRTT, 6.8 ± 2.5 (3-13) mm/15 s. Dazzle reflex was positive in four birds examined. Pathologies included cataracts (n = 7 birds), corneal fibrosis (n = 3), endothelial pigment (n = 2), uveal cysts (n = 1), lens luxation (n = 1), and uveitis (n = 1). Ocular microbiome showed high diversity of taxa. CONCLUSIONS: Baseline ocular parameters and incidence of ophthalmic pathology assist veterinarians with disease screening for Chilean flamingos, while the ocular microbiome showed high diversity.

Avian haemosporidians of the genera Plasmodium and Haemoproteus from resident and Neotropical migrant birds in Colombia.

Avian haemosporidians of the genera Plasmodium and Haemoproteus are a group of widely distributed blood parasites that can negatively affect the fitness of their hosts. Colombia contains the greatest diversity of birds on the planet, but knowledge about the associations between haemosporidian and its avifauna is scarce and fragmented. We collected blood samples from 255 birds (203 residents and 52 neotropical migrants) belonging to 27 families and 108 species. The study was conducted in six localities in the inter-Andean valleys of the Cauca and Magdalena rivers. Parasites of the genera Plasmodium and Haemoproteus were identified in the samples by morphological and molecular analysis of a fragment of the mitochondrial gene cyt b. Among the samples, 9.3% (n = 24) were positive for Plasmodium or Haemoproteus. Co-infection with Plasmodium and Haemoproteus was found in Red-eyed Vireo. Seventeen haemosporidian lineages were identified, five of which were reported for the first time in resident birds (Common Ground Dove, Checker-throated Stipplethroat, Tropical Kingbird, Pale-breasted Thrush, and Ruddy-breasted Seedeater) and one in the Summer Tanager (neotropical migrant). The research results confirm the wide diversity of haemosporidian present in tropical lowlands and the possible role of neotropical migratory birds in dissemination on haemosporidian along their migratory routes.

Detection of avian reovirus (ARV) by ELISA based on recombinant σB, σC and σNS full-length proteins and protein fragments.

Introduction. Avian reovirus (ARV) is associated with arthritis/tenosynovitis and malabsorption syndrome in chickens. The σC and σB proteins, both exposed to the virus capsid, are highly immunogenic and could form the basis for diagnostic devices designed to assess the immunological status of the flock.Gap Statement. Commercial ARV ELISAs cannot distinguish between vaccinated and infected animals and might not detect circulating ARV strains.Aim. We aimed to develop a customized test to detect the circulating field ARV strains as well as distinguish between vaccinated and unvaccinated animals.Methodology. We developed ELISA assays based on recombinant (r) σB, σC and the nonstructural protein σNS and tested them using antisera of vaccinated and unvaccinated chickens as well as negative controls. Fragments of σB and σC proteins were also used to study regions that could be further exploited in diagnostic tests.Results. Vaccinated and unvaccinated birds were positive by commercial ELISA, with no difference in optical density values. In contrast, samples of unvaccinated animals showed lower absorbance in the rσB and rσC ELISA tests and higher absorbance in the rσNS ELISA test than the vaccinated animals. Negative control samples were negative in all tests. Fragmentation of σB and σC proteins showed that some regions can differentiate between vaccinated and unvaccinated animals. For example, σB amino acids 128-179 (σB-F4) and σC amino acids 121-165 (σC-F4) exhibited 85 and 95% positivity among samples of vaccinated animals but only 5% and zero positivity among samples of unvaccinated animals, respectively.Conclusion. These data suggest that unvaccinated birds might have been exposed to field strains of ARV. The reduction in absorbance in the recombinant tests possibly reflects an increased specificity of our test since unvaccinated samples showed less cross-reactivity with the vaccine proteins immobilized on ELISAs. The discrepant results obtained with the protein fragment tests between vaccinated and unvaccinated animals are discussed in light of the diversity between ARV strains.

Whole genome sequencing of low pathogenicity avian influenza virus (H6N2) detected from a Brazilian teal (Amazonnetta brasiliensis) in Brazil, 2023.

The whole genome sequence of a low pathogenicity avian influenza virus (H6N2) was sequenced from a Brazilian teal (Amazonetta brasiliensis) in Brazil, 2023. Phylogenetic analysis of the whole genome revealed a distinct genome pertaining to South American LPAIV from 2014 to 2016, indicating extensive circulation among South American wild birds.

Systematics and life cycles of four avian schistosomatids from Southern Cone of South America.

Relative to the numerous studies focused on mammalian schistosomes, fewer include avian schistosomatids particularly in the southern hemisphere. This is changing and current research emerging from the Neotropics shows a remarkable diversity of endemic taxa. To contribute to this effort, nine ducks (Spatula cyanoptera, S.versicolor, Netta peposaca), 12 swans (Cygnus melancoryphus) and 1,400 Physa spp. snails from Chile and Argentina were collected for adults and larval schistosomatids, respectively. Isolated schistosomatids were preserved for morphological and molecular analyses (28S and COI genes). Four different schistosomatid taxa were retrieved from birds: Trichobilharzia sp. in N. peposaca and S. cyanoptera that formed a clade; S.cyanoptera and S. versicolor hosted Trichobilharzia querquedulae; Cygnus melancoryphus hosted the nasal schistosomatid, Nasusbilharzia melancorhypha; and one visceral, Schistosomatidae gen. sp., which formed a clade with furcocercariae from Argentina and Chile from previous work. Of the physid snails, only one from Argentina had schistosomatid furcocercariae that based on molecular analyses grouped with T. querquedulae. This study represents the first description of adult schistosomatids from Chile as well as the elucidation of the life cycles of N.melancorhypha and T. querquedulae in Chile and Neotropics, respectively. Without well-preserved adults, the putative new genus Schistosomatidae gen. sp. could not be described, but its life cycle involves Chilina spp. and C. melancoryphus. Scanning electron microscopy of T. querquedulae revealed additional, undescribed morphological traits, highlighting its diagnostic importance. Authors stress the need for additional surveys of avian schistosomatids from the Neotropics to better understand their evolutionary history.

Unveiling the traits of antibiotic resistance and virulence in Escherichia coli obtained from poultry waste.

Antibiotic resistance and virulence factors in avian pathogenic Escherichia coli (APEC) have become significant concerns, contributing to adverse environmental effects. The extensive use of antibiotics in poultry farming has resulted in the emergence of antibiotic-resistant APEC strains. This study prioritizes the molecular screening of APEC to uncover their antibiotic resistance and virulence attributes, with specific attention to their environmental impact. To address the imperative of understanding APEC pathogenesis, our study analyzed 50 poultry waste samples including 10 poultry litter, 15 fecal matter, 15 wastewater, and 10 anatomical waste samples. For the presence of virulence genes, 35 Escherichia coli isolates were subjected to molecular characterization. Amongst these, 27 were APEC strains demonstrating the presence of at least four virulence genes each. Notably, virulence genes such as fimH, ompA, ybjX, waaL, cvaC, hlyF, iss, ompT, and iroN were observed among all the E. coli isolates. Furthermore, eleven of the APEC strains exhibited resistance to tetracycline, ampicillin, sulphonamides, and fluoroquinolones.These findings highlight the role of APEC as a potential source of environmental pollution serving as a reservoir for virulence and resistance genes. Understanding the dynamics of antibiotic resistance and virulence in APEC is essential due to its potential threat to broiler chickens and the broader population through the food chain, intensifying concerns related to environmental pollution. Recognizing the ecological impact of APEC is essential for developing effective strategies to mitigate environmental pollution and safeguard the health of ecosystems and human populations.

Sequence-based epitope mapping of high pathogenicity avian influenza H5 clade 2.3.4.4b in Latin America.

High Pathogenicity Avian Influenza (HPAI) poses a significant threat to public and animal health. Clade 2.3.4.4b recently emerged from the Eastern hemisphere and disseminated globally, reaching the Latin American (LATAM) region in late 2022 for the first time. HPAI in LATAM has resulted in massive mortalities and culling of poultry and wild birds, causing infection in mammals and humans. Despite its meaningful impact in the region, only occasional evidence about the genetic and epitope characteristics of the introduced HPAI is reported. Hence, this study seeks to phylogenetically characterize the molecular features and the source of HPAI in LATAM by evaluating potential antigenic variations. For such a purpose, we analyzed 302 whole genome sequences. All Latin American viruses are descendants of the 2.3.4.4b clade of the European H5N1 subtype. According to genomic constellations deriving from European and American reassortments, the identification of three major subtypes and eight sub-genotypes was achievable. Based on the variation of antigenic motifs at the HA protein in LATAM, we detected three potential antigenic variants, indicating the HA-C group as the dominant variant. This study decidedly contributes to unraveling the origin of the 2.3.4.4b clade in LATAM, its geographic dissemination, and evolutionary dynamics within Latin American countries. These findings offer useful information for public health interventions and surveillance initiatives planned to prevent and manage the transmission of avian influenza viruses.

Stranding and mass mortality in humboldt penguins (Spheniscus humboldti), associated to HPAIV H5N1 outbreak in Chile.

The highly pathogenic Avian Influenza virus (HPAIV) H5N1 has caused a global outbreak affecting both wild and domestic animals, predominantly avian species. To date, cases of the HPAIV H5 Clade 2.3.4.4b in penguins have exclusively been reported in African Penguins. In Chile, the virus was confirmed in pelicans in December 2022 and subsequently spread across the country, affecting several species, including Humboldt penguins. This study aims to provide an overview of the incidents involving stranded and deceased Humboldt penguins and establish a connection between these events and HPAIV H5N1. Historical data about strandings between 2009 and 2023 was collected, and samples from suspected cases in 2023 were obtained to confirm the presence of HPAIV H5N1. Between January and August 2023, 2,788 cases of stranded and deceased penguins were recorded. Out of these, a total of 2,712 penguins deceased, evidencing a significative increase in mortality starting in early 2023 coinciding with the introduction and spreading of HPAIV H5N1 in the country. Thirty-seven events were categorized as mass mortality events, with the number of deceased penguins varying from 11 to 98. Most cases (97 %) were observed in the North of Chile. One hundred and eighty-one specimens were subjected to HPAIV diagnosis, four of which tested positive for HPAIV H5N1. Spatial analysis validates the correlation between mass mortality events and outbreaks of HPAIV in Chile. However, the limited rate of HPAIV H5N1 detection, which can be attributed to the type and quality of the samples, requiring further exploration.

Highly pathogenic avian influenza H5N1 virus infections in pinnipeds and seabirds in Uruguay: Implications for bird-mammal transmission in South America.

The highly pathogenic avian influenza viruses of clade 2.3.4.4b have caused unprecedented deaths in South American wild birds, poultry, and marine mammals. In September 2023, pinnipeds and seabirds appeared dead on the Uruguayan Atlantic coast. Sixteen influenza virus strains were characterized by real-time reverse transcription PCR and genome sequencing in samples from sea lions (Otaria flavescens), fur seals (Arctocephalus australis), and terns (Sterna hirundinacea). Phylogenetic and ancestral reconstruction analysis showed that these strains have pinnipeds most likely as the ancestral host, representing a recent introduction of clade 2.3.4.4b in Uruguay. The Uruguayan and closely related strains from Peru (sea lions) and Chile (sea lions and a human case) carry mammalian adaptative residues 591K and 701N in the viral polymerase basic protein 2 (PB2). Our findings suggest that clade 2.3.4.4b strains in South America may have spread from mammals to mammals and seabirds, revealing a new transmission route.

Novel Tick-Borne Anaplasmataceae Genotypes in Tropical Birds from the Brazilian Pantanal Wetland.

Despite numerous reports of Anaplasmataceae agents in mammals worldwide, few studies have investigated their occurrence in birds. The present study aimed to investigate the occurrence and molecular identity of Anaplasmataceae agents in birds from the Pantanal wetland, Brazil. Blood samples were collected from 93 different species. After DNA extraction, samples positive for the avian ß-actin gene were subjected to both a multiplex quantitative real-time (q)PCR for Anaplasma and Ehrlichia targeting the groEL gene and to a conventional PCR for Anaplasmataceae agents targeting the 16S rRNA gene. As a result, 37 (7.4%) birds were positive for Anaplasma spp. and 4 (0.8%) for Ehrlichia spp. in the qPCR assay; additionally, 13 (2.6%) were positive for Anaplasmataceae agents in the PCR targeting the 16S rRNA gene. The Ehrlichia 16S rRNA sequences detected in Arundinicola leucocephala, Ramphocelus carbo, and Elaenia albiceps were positioned closely to Ehrlichia sp. Magellanica. Ehrlichia dsb sequences detected in Agelasticus cyanopus and Basileuterus flaveolus grouped with Ehrlichia minasensis. The 16S rRNA genotypes detected in Crax fasciolata, Pitangus sulphuratus and Furnarius leucopus grouped with Candidatus Allocryptoplasma. The 23S-5S genotypes detected in C. fasciolata, Basileuterus flaveolus, and Saltator coerulescens were related to Anaplasma phagocytophilum. In conclusion, novel genotypes of Anaplasma, Ehrlichia, and Candidatus Allocryptoplasma were detected in birds from the Pantanal wetland.

Lymphomas in seabirds: case reports in a black skimmer (Rynchops niger) and a brown booby (Sula leucogaster).

A black skimmer (Rynchops niger) and a brown booby (Sula leucogaster) were rescued and gross, histopathological, immunohistochemical and polymerase chain reaction evaluations were conducted to investigate the cause of death. There were neoplastic infiltrations of CD3+ PAX5- lymphocytes in the black skimmer and CD3- PAX5+ lymphocytes in the brown booby. Molecular assays for viral agents were negative in both cases. This is the first report of disseminated lymphoma as the cause of stranding and death in these species in Brazil.

Antimicrobial Sensitivity Profile in Psittacine Birds at an Avian Teaching Hospital: A Retrospective Study, 2015-2022.

Veterinary hospitals house patient populations with diverse infectious statuses, microbiota, and histories of prior antibiotic therapy. Choanal swabs are commonly used for assessing the upper respiratory tract of birds for bacterial disease, with the samples submitted for cytologic testing and/or culture and antimicrobial sensitivity testing. The aim of this retrospective study was to identify and quantify bacteria isolated from choanal swabs collected from psittacine patients at a veterinary teaching hospital in Mexico City, Mexico. Data regarding bacterial isolates from choanal swabs were obtained from the medical records of companion psittacines suspected of upper respiratory bacterial disease that presented between November 2015 and December 2022. A total of 47.8% (175 of 366) of the bacterial isolates were from specimens obtained from red-lored Amazons (Amazona autumnalis). Gram-negative bacteria predominated, with 27 different genera identified. Klebsiella, Staphylococcus, and Escherichia were the most frequently isolated genera. A total of 90.4% (331 of 366) of the isolates were resistant to at least 1 antibiotic tested in the sensitivity panel, and a single Klebsiella isolate was resistant to 13 different antibiotics. Gentamicin had a high percentage of efficacy (79.5%; 182 of 229) against the bacterial isolates, whereas isolates tested against sulfonamide-trimethoprim (46.7%, 98 of 210), streptomycin (43.8%; 88 of 201), and clindamycin (12.9%; 15 of 116) had susceptibilities <50%. This is the first study to report common bacterial isolates and their antimicrobial susceptibility patterns from choanal swab samples collected from companion psittacines suspected of upper respiratory disease in Mexico. Clinicians can use the information presented in this study as a guide for therapeutic decision-making when managing upper respiratory bacterial infections in companion psittacine patients.

Lack of Highly Pathogenic Avian Influenza H5N1 in the South Shetland Islands in Antarctica, Early 2023.

In January 2023, an active surveillance initiative was undertaken in the South Shetland Islands, Antarctica, with the specific objective of ascertaining evidence for the presence of avian influenza, and specifically the highly pathogenic avian influenza virus subtype H5N1 (HPAIV H5N1). The investigation encompassed diverse locations, including Hanna Point (Livingston Island), Lions Rump (King George Island), and Base Escudero (King George Island), with targeted observations on marine mammals (southern elephant seals), flying birds (the kelp gull, snowy sheathbill and brown skua), and penguins (the chinstrap penguin and gentoo penguin). The study encompassed the examination of these sites for signs of mass mortality events possibly attributable to HPAIV H5N1, as well as sampling for influenza detection by means of real-time RT-PCR. Two hundred and seven (207) samples were collected, including 73 fecal samples obtained from the environment from marine mammals (predominantly feces of southern elephant seals), and 77 cloacal samples from penguins of the genus Pygoscelis (predominantly from the gentoo penguin). No evidence of mass mortality attributable to HPAIV H5N1 was observed, and all the collected samples tested negative for the presence of the virus, strongly suggesting the absence of the virus in the Antarctic territory during the specified period. This empirical evidence holds significant implications for both the ecological integrity of the region and the potential zoonotic threats, underscoring the importance of continued surveillance and monitoring in the Antarctic ecosystem.

Chlamydia gallinacea in Brazilian backyard chicken farms.

Avian chlamydiosis is a bacterial infectious disease of birds, considered until recently caused only by Chlamydia psittaci, that now includes the newly described species C. buteonis, C. avium, and C. gallinacea, associated with several avian hosts. Since its recognition as a species in 2014 and having chickens as one of its main hosts, C. gallinacea has already been described in backyard poultry on all continents. The present study aimed to survey by molecular techniques the presence and species of Chlamydia spp. in backyard chickens from three states of the southern region of Brazil (Paraná-PR, Santa Catarina-SC, and Rio Grande do Sul-RS). DNA extracted from cloacal swab samples were tested by polymerase chain reaction (PCR) for different species of Chlamydia, namely Chlamydiaceae (23 S rRNA gene), C. psittaci (ompA gene), C. avium (enoA gene) and C. gallinacea (gidA and enoA genes). The 16 S rRNA gene was used for sequencing and phylogenetic analysis. A total of 582 backyard chicken samples were collected and grouped in 238 pools, from 134 properties in 59 municipalities. Chlamydiaceae was detected in 25.2% (60/238) of the samples, in 38.8% (52/134) of the properties and in 66.1% (39/59) of the municipalities. None of the samples yielded positive PCR results for C. psittaci or C. avium. For C. gallinacea, the overall percentage was 16.3% (39/238) according to the results of gidA and enoA genes. Sequence analysis confirmed that the samples corresponded to C. gallinacea. This is the first report of C. gallinacea in Brazil.