Introduction: Chlamydia psittaci is a gram-negative obligate intracellular pathogen of birds. Poultry infections lead to economic losses and can be transmitted to humans. No vaccine is available and the bacterium-host cell interaction is not completely understood. Replicating bacteria cause pneumonia, but C. psittaci can also be non-replicating and persistent inside the cytoplasm of avian cells. RT-qPCR provides insight into the molecular pathogenesis of both active replicating and persistent Chlamydia psittaci in birds, but requires identification of stably expressed reference genes to avoid biases. Material and Methods: We investigated the expression stability of 10 C. psittaci candidate reference genes for gene expression analysis during normal growth and penicillin-induced persistence. C. psittaci Cal10 was cultured in HeLa229 and RNA was extracted. The expression level of each candidate was examined by RT-qPCR and Cq values were analysed using geNorm. Results: The genes tyrS, gidA, radA, and 16S rRNA ranked among the most stably expressed. The final selected reference genes differed according to the bacterial growth status (normal growth versus persistent status), and the time points selected during the duration of the normal chlamydial developmental cycle. Conclusion: The study data show the importance of systematic validation of reference genes to confirm their stability within the strains and under the conditions selected.

Aspergillus species are widely distributed throughout the world and can develop parasitic and saprophytic ways of life, allowing Aspergillus to infect living hosts, including plants, insects, birds and mammals. The most common form of aspergillosis in poultry and other birds is respiratory infection. Clinical manifestations depend on the infective dose, pre-existing diseases, and the immune response of the host. The aim of the present research was to study aspergillosis in domestic and wild birds from Argentina. We carried out morphological and molecular identification, and determination of antifungal susceptibility against seven antifungal drugs. Six birds from different cities of Buenos Aires Province of Argentina were studied. Three of the samples belonged to broiler chicks, while the other three belonged to an eagle, a pheasant, and a kelp gull. Two isolates were identified as Aspergillus fumigatus by morphological characteristics and growth at 50 °C. Morphology and BenA sequencing enabled us to identify three isolates as Aspergillus flavus, and one as Aspergillus sydowii. All antifungal drugs tested showed low MIC values, ranging from 0.008 to 1 mg/L. Aspergillosis in birds causes high economic losses and could be controlled by sanitation, avoidance of moldy food, nest and litter and reducing stress factors.

Knowledge of the enterobacteria present in the roadside hawk can bring about an understanding of infectious diseases that can affect this bird, as well as other animals and/or humans, while also adding information of great ecological importance. Thus, the aim of the study was to determine the enterobacteria present in the cloaca of captive roadside hawks and antimicrobial susceptibility profile. Initially, cloacal samples from nine specimens were collected with the aid of swabs. Samples were placed in petri dishes with MacConkey agar, Hektoen agar, EMB agar and Salmonella-Shigella (SS) agar and incubated for 24 h at 35°C. After incubation, the microorganisms were submitted to biochemical testing to confirm the presence of enterobacteria. Thereafter, the susceptibility profile of bacteria to antimicrobial agents was evaluated by a disk diffusion test according to the Clinical and Laboratory Standards Institute (CLSI). Escherichia coli (77.8%), Klebsiella oxytoca (11.1%), Klebsiella pneumoniae (11.1%) and Salmonella spp. (55.6%) were isolated from the collected samples. Among the isolates, some bacteria showed resistance to up to three antimicrobial agents. This study has brought greater insight about the enterobacteria present in the roadside hawk (Rupornis magnirostris), exhibiting a significant percentage of enterobacteria important to public health; also, it showed the occurrence of strains with resistance profile to antimicrobial agents.

Ticks (Acari: Ixodidae) are obligatory hematophagous ectoparasites of a variety of vertebrate hosts and play an important role in the transmission and ecology of infectious pathogens causing diseases in humans and animals worldwide. Sixty-eight species of ticks exist in Brazil, and at least 23 are found parasitizing wild birds. This number is increasing with the advent of new studies highlighting the underestimated role of birds in the life cycle of these arthropods. In South America, many of these ticks are involved in epidemiology of the life-threatening spotted fever diseases caused by bacteria from the genus Rickettsia (Rickettsiales: Rickettsiaceae). The aim of this paper is to present up-to-date knowledge about the bird-tick fauna of Brazil and their association with rickettsioses. The available literature concerning ticks on birds and tick-borne diseases related to these ticks in Brazil has been revised. It could be concluded that birds play a primary role in life cycles of various tick species, especially during immature stages (larvae and nymphs). The best known is a bird-tick fauna from the Atlantic Forest and from Brazilian savannah called Cerrado in southern and central Brazil, respectively. On the other hand, the knowledge about bird tick parasitism from other Brazilian biomes such as the Amazon, Caatinga, Pantanal and Pampas regions is very scarce and requires further study. Moreover, no studies about the role of birds as mobile hosts for spreading ticks to new areas exist, nor has their role in the natural life cycle of Rickettsia been thoroughly examined.

The growing use of ophthalmic examination as a screening tool in birds intended for reintroduction into natural environments over the last few years has given renewed significance to avian ophthalmology in the context of free-ranging and captive bird conservation. The eye plays a vital role in prey detection and capture by birds of prey. The remarkable eyesight of such birds makes them interesting subjects for avian visual system anatomical and histological investigation. This study set out to describe histological features of the eyeball of ubiquitous birds of prey in Brazil (Falconiformes, Accipitriformes and Strigiformes). Twenty enucleated cadaveric eyeballs obtained from birds with natural death, Caracara plancus, Falco sparverius, Rupornis magnirostris, Megascops choliba and Athene cunicularia were used. Routinely prepared histological slides stained with hematoxylin and eosin were analyzed under light microscopy. Similarities and variations in ocular structures between the different bird species studied were highlighted in this study, with major differences concerning the lens and retina. This study highlights the importance of determining the ocular histological pattern of the species so they can be better understood. These results may well assign baseline information of the species and assist in eye histopathological diagnostics.

Trafficking in wild animals represents one of the main illicit activities in the world. In Brazil, among the main trafficked species the songbirds of the Passeriform Order stand out. The distress to which these birds are exposed, especially the newly caught ones, and the unhealthy conditions to which they are subjected, cause, in addition to the damage to well-being, an important drop in resistance, which exacerbates infectious and parasitic conditions. Clinical assessments and coproparasitological examinations were carried out using the Willis-Mollay method on 102 passerines from apprehension in western Paraná. Of the total number of animals evaluated, 76% (78/102) had hyperkeratosis in the pelvic limbs, 55% (56/102) were infested with mites on remiges and 54% (52/102) had changes in warping. The results indicated 94% (96/102) of positivity for endoparasites, of which 96% (92/96) were for coccidian oocysts, 1% (1/96) for tenia eggs and 3% (3/96) for mixed infection (coccid oocysts and tenia eggs). These findings corroborate that the poor conditions of hygiene, nutrition and the high stocking density observed in illegal housing can predispose birds to more severe clinical manifestations.

The objective of this study was to detect the presence of anti-Toxoplasma gondii antibodies in serum samples from 100 sparrows (Passer domesticus Linnaeus, 1758) that were caught in an urban area in southern Brazil. The modified agglutination test (MAT) was used to investigate anti-T. gondii antibodies and samples with a cut-off dilution > 5 were considered positive. Among the 100 serum samples analyzed, 80 (80%) were reactive. These results demonstrate that P. domesticus may play an important role in the epidemiological chain of T. gondii, since it is widely distributed throughout Brazil, and it may act as a source of infection to domestic, semi-domestic cats and to free-living wild felids.

Passerines such as canaries or finches are the most unlawfully captured species that are sent to wildlife centers in São Paulo, Brazil. Captured birds may have infection by opportunistic bacteria in stressful situations. This fact becomes relevant when seized passerine are reintroduced. The aim of this study was to evaluate the health state of finches from illegal wildlife trade using microbiological approaches. Microbiological samples were collected by cloacal and tracheal swabs of 100 birds, captured during 2012 and 2013. The results indicate high frequency of gram-negative bacteria in feces and oropharynx, especially from the Enterobacteriaceae family (97.5%). The most frequent genera were Escherichia coli (46.5%) and Klebsiella pneumoniae (10.4%). Enterobacter cloacae, Serratia liquefaciens, Serratia spp. Klebsiella oxytoca and Citrobacter freundii were isolated with lower frequency from asymptomatic birds. The presence of enteropathogenic Escherichia coli (EPEC) and Shiga toxin-producing strain (STEC) confirm the zoonotic risks and public health concern.

Introduction: The genomes of nine H5 subtypes of low pathogenic avian influenza virus (LPAIV) strains identified in wild birds in Poland between 2010 and 2015 were sequenced, and their phylogenetic relationship was determined. Material and Methods: AIV genome segments were amplified by RT-PCR and the PCR products were sequenced using Sanger method. Phylogenetic trees were generated in MEGA6 software and digital genotyping approach was used to visualise the relationship between analysed strains and other AIVs. Results: High genetic diversity was found in the analysed strains as multiple subgroups were identified in phylogenetic trees. In the HA tree, Polish strains clustered in two distinct subclades. High diversity was found for PB2, PB1, PA and NP, since 5-8 sublineages could be distinguished. Each strain had a different gene constellation, although relationship of as much as six out of eight gene segments was observed between two isolates. A relationship with poultry isolates was found for at least one segment of each Polish strain. Conclusion: The genome configuration of tested strains indicates extensive reassortment, although the preference for specific gene constellation could be noticed. A significant relationship with isolates of poultry origin underlines the need for constant monitoring of the AIV gene pool circulating in the natural reservoir.

Introduction: Chlamydia psittaci is a gram-negative obligate intracellular pathogen of birds. Poultry infections lead to economic losses and can be transmitted to humans. No vaccine is available and the bacterium-host cell interaction is not completely understood. Replicating bacteria cause pneumonia, but C. psittaci can also be non-replicating and persistent inside the cytoplasm of avian cells. RT-qPCR provides insight into the molecular pathogenesis of both active replicating and persistent Chlamydia psittaci in birds, but requires identification of stably expressed reference genes to avoid biases. Material and Methods: We investigated the expression stability of 10 C. psittaci candidate reference genes for gene expression analysis during normal growth and penicillin-induced persistence. C. psittaci Cal10 was cultured in HeLa229 and RNA was extracted. The expression level of each candidate was examined by RT-qPCR and Cq values were analysed using geNorm. Results: The genes tyrS, gidA, radA, and 16S rRNA ranked among the most stably expressed. The final selected reference genes differed according to the bacterial growth status (normal growth versus persistent status), and the time points selected during the duration of the normal chlamydial developmental cycle. Conclusion: The study data show the importance of systematic validation of reference genes to confirm their stability within the strains and under the conditions selected.