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.

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.

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.