Salmonella infects poultry, and it is also a human foodborne pathogen. This bacterial genus is classified into several serovars/lineages, some of them showing high antimicrobial resistance (AMR). The ease of Salmonella transmission in farms, slaughterhouses, and eggs industries has made controlling it a real challenge in the poultry-production chains. This review describes the emergence, dissemination, and AMR of the main Salmonella serovars and lineages detected in Brazilian poultry. It is reported that few serovars emerged and have been more widely disseminated in breeders, broilers, and layers in the last 70 years. Salmonella Gallinarum was the first to spread on the farms, remaining as a concerning poultry pathogen. Salmonella Typhimurium and Enteritidis were also largely detected in poultry and foods (eggs, chicken, turkey), being associated with several human foodborne outbreaks. Salmonella Heidelberg and Minnesota have been more widely spread in recent years, resulting in frequent chicken/turkey meat contamination. A few more serovars (Infantis, Newport, Hadar, Senftenberg, Schwarzengrund, and Mbandaka, among others) were also detected, but less frequently and usually in specific poultry-production regions. AMR has been identified in most isolates, highlighting multi-drug resistance in specific poultry lineages from the serovars Typhimurium, Heidelberg, and Minnesota. Epidemiological studies are necessary to trace and control this pathogen in Brazilian commercial poultry production chains.

Salmonella serotype Minnesota has been increasingly detected in Brazilian poultry farms and food products (chicken meat, eggs) in recent years. In addition, S. Minnesota isolates from poultry are generally resistant to several antibiotics and persistent in farm environments. The present study aimed to assess phylogenomic diversity of S. Minnesota isolates from the poultry production chain in Brazil. In total, 107 worldwide S. Minnesota whole genomes (including 12 from Brazil) were analyzed using a comparative approach. Phylogenetic analysis demonstrated two clades more related to poultry production in Brazil: S. Minnesota poultry lineages I and II (SM-PLI and SM-PLII). Phylodynamic analysis demonstrated that SM-PLI had a common ancestor in 1915, while SM–PLII originated circa 1971. SM-PLII encompassed a higher number of isolates and presented a recent increase in effective population size (mainly from 2009 to 2012). Plasmids IncA/C2 and ColRNA, antimicrobial resistance genes (aph(3′)-Ia, blaCMY-2, qnrB19, sul2, and tet(A)) and mainly a virulence genetic cluster (including the yersiniabactin operon) were detected in isolates from SM-PLI and/or SM-PLII. This study demonstrates the dissemination of two distinct S. Minnesota lineages with high resistance to antibiotics and important virulence genetic clusters in Brazilian poultry farms.

Feline leukemia virus (FeLV) is a retrovirus distributed worldwide in domestic cats and with different outcomes (progressive, regressive, abortive, focal). The present study reports an epidemiological survey of FeLV frequency and the evaluation of some risk factors and the two main disease outcomes (progressive and regressive) in an urban cat population from Brazil. A total of 366 cats with sociodemographic information and p27 FeLV antigen test performed were included in the study. FeLV DNA (provirus) in the blood samples of all cats was detected via real-time polymerase chain reaction (qPCR). Plasma samples from 109 FeLV-positive and FeLV-negative cats were also submitted to reverse transcription (RT-qPCR) to determine the FeLV viral load. The results demonstrated that 112 (30.6%) cats were positive through the p27 antigen and/or qPCR. A risk factor analysis demonstrated that cats without vaccination against FeLV (OR 9.9, p < 0.001), clinically ill (OR 2.9, p < 0.001), with outdoors access (OR 2.7, p < 0.001), and exhibiting apathetic behavior (OR 3.1, p < 0.001) were more likely to be infected with FeLV. FeLV-infected cats were also more likely to present with anemia (OR 13, p < 0.001) and lymphoma (OR 13.7, p = 0.001). A comparative analysis of the different detection methods in a subset of 109 animals confirmed FeLV infection in 58 cats, including 38 (65.5%) with progressive, 16 (27.6%) with regressive, and 4 (6.9%) with probably focal outcome diseases. In conclusion, this study demonstrates a high prevalence of FeLV in this urban cat population from Brazil and highlights the need to establish more effective prevention strategies (such as viral testing, vaccination programs, specific care for FeLV-positive cats) to reduce diseases associated with this virus in Brazil.

Infectious bronchitis virus (IBV) is a pathogen affecting poultry flocks worldwide. GI-23 is an IBV lineage with a rapid spread into different continents of the world, and it was reported for the first time in South American/Brazilian broiler farms last year. This study aimed to investigate the recent introduction and epidemic spread of IBV GI-23 in Brazil. Ninety-four broiler flocks infected with this lineage were evaluated from October 2021 to January 2023. IBV GI-23 was detected using real-time RT-qPCR, and the S1 gene hypervariable regions 1 and 2 (HVR1/2) were sequenced. S1 complete and HVR1/2 nucleotide sequence datasets were used to carry out phylogenetic and phylodynamic analyses. Brazilian IBV GI-23 strains clustered into two specific subclades (SA.1 and SA.2), both in tree branches with IBV GI-23 from Eastern European poultry-producing countries, suggesting two independent and recent introductions (around 2018). Viral phylodynamic analysis showed that the IBV GI-23 population increased from 2020 to 2021, remaining constant for one year and declining in 2022. S1 amino acid sequences from Brazilian IBV GI-23 presented specific and characteristic substitutions in the HVR1/2 for subclades IBV GI-23 SA.1 and SA.2. This study brings new insights into the introduction and recent epidemiology of IBV GI-23 in Brazil.

The avian infectious bronchitis virus is classified into serotypes or genotypes (or both) in different poultry-producing countries of the world. In Brazil, Massachusetts type (Mass), used as a live vaccine, and local field Brazilian variants (genotypes; BR) predominate in the commercial poultry flocks. This study describes the development and validation of two real-time reverse-transcription polymerase chain reactions (RT-qPCR) for the specific detection of Mass and BR genotypes in allantoic fluids and clinical samples. Genotype-specific primers, combined with a generic probe targeted to the S1 gene, originated Mass RT-qPCR and BR RT-qPCR–specific assays. Analytical sensitivity and linearity of these assays were determined in comparison with an IBV generic real-time RT-PCR based on the 5′ untranslated region (5′UTR RT-qPCR). Mass RT-qPCR detected five Mass field isolates, three vaccine samples, and one coinfected sample (BR and Mass) while BR RT-qPCR detected 16 BR field isolates. Both assays were linear (R² > 0.98), reproducible, and as sensitive as the classical 5′UTR RT-qPCR used to detect IBV. In the analysis of 141 IBV clinical samples, 8 were positive for Mass RT-qPCR, 76 for BR RT-qPCR, and 2 for both assays. In the remaining 55 samples, 25 were positive only for 5′UTR RT-qPCR and 30 were negative for the three assays. In conclusion, both assays were able to detect Mass and BR genotypes, allowing rapid and easy IBV molecular typing from allantoic fluids and clinical samples. Un método de transcripción reversa y reacción en cadena de la polimerasa en tiempo real para la diferenciación de vacunas tipo Massachusetts y genotipos de campo brasileros del virus de la bronquitis infecciosa aviar. El virus de la bronquitis infecciosa aviar se clasifica en serotipos o genotipos (o en ambos) en diferentes países productores avícolas en el mundo. En Brasil, el tipo Massachusetts (Mass), utilizado como una vacuna viva, y variantes de campo locales brasileras (genotipos; BR) predominan en la avicultura comercial. Este estudio describe el desarrollo y la validación de dos métodos de transcripción reversa y reacción en cadena de la polimerasa en tiempo real (RT-qPCR) para la detección específica de los genotipos Massachusetts y BR en líquidos alantoideo y en muestras clínicas. Mediante el uso de iniciadores específicos de genotipo en combinación con una sonda genérica dirigida al gene S1 se originaron dos ensayos RT-qPCR específicos para los genotipos Massachusetts y BR. Se determinaron la sensibilidad analítica y la linealidad de estos ensayos en comparación con un método genérico de RT-PCR en tiempo real basado en la región no traducida 5′(5′UTR RT-qPCR). El método RT-qPCR específico para Massachusetts detectó cinco aislamientos de campo tipo Mass, tres muestras de la vacuna, y una muestra coinfectada (BR y Mass), mientras que el método RT-qPCR específico para el genotipo BR detectó 16 aislamientos de campo tipo BR. Ambos ensayos fueron lineales (R² > 0.98), reproducibles, y tan sensible como el método clásico para la región 5′UTR que se utiliza para detectar al virus de bronquitis infecciosa. En el análisis de 141 muestras clínicas, ocho fueron positivas mediante el método RT-qPCR específico para Mass, 76 mediante el método específico para genotipo BR y dos muestras fueron positivas mediante ambos ensayos. En las 55 muestras restantes, 25 fueron positivas sólo mediante el método dirigido a la región 5′UTR y 30 fueron negativos para los 3 ensayos. En conclusión, ambos ensayos fueron capaces de detectar genotipos Mass y BR, lo que permite una tipificación molecular para el virus de la bronquitis infecciosa más rápida y fácil a partir de fluidos alantoideo y de muestras clínicas.