Pathogenicity of GI-23 Avian Infectious Bronchitis Virus Strain Isolated in Brazil.

IBV variants belonging to the GI-23 lineage have circulated since 1998 in the Middle East and have spread to several countries over time. In Brazil, the first report of GI-23 occurred in 2022. The study aimed to evaluate the in vivo pathogenicity of exotic variant GI-23 isolates. Biological samples were screening by real-time RT-PCR and classified in to GI-1 or G1-11 lineages. Interestingly, 47.77% were not classified in these lineages. Nine of the unclassified strains were sequenced and showed a high similarity to the GI-23 strain. All nine were isolated and three, were studied for pathogenicity. At necropsy, the main observations were the presence of mucus in the trachea and congestion in the tracheal mucosa. In addition, lesions on the tracheas showed marked ciliostasis, and the ciliary activity confirmed the high pathogenicity of isolates. This variant is highly pathogenic to the upper respiratory tract and can cause severe kidney lesions. This study confirm a circulation of GI-23 strain in the country and report, to first time, the isolation of an exotic variant of IBV in Brazil.

Health profile of free-range wild boar (Sus scrofa) subpopulations hunted in Santa Catarina State, Brazil.

Wild boars represent a potential dissemination source of important pathogens to public and animal health, since they can host several pathogens. This study aimed to evaluate the health profile of wild boars hunted for population control in the state of Santa Catarina (SC), south of Brazil. For this study, tissue and blood samples were collected from 61 wild boars hunted from October 2017 to November 2018. All 61 serum samples were screened for antibodies by different assays, presenting the following seroprevalence: 52.4% for porcine circovirus type 2 (PCV2); 21.3% for Leptospira spp.; 19.7% for Mycoplasma hyopneumoniae; 13.1% for hepatitis E virus (HEV); and 9.8% for influenza A virus (IAV). No seroreaction was observed for Brucella spp. and classical swine fever virus (CSFV). At necropsy, the main lesions observed were evidence of pulmonary metastrongylid parasites, haemorrhagic lymph nodes and white-spotted liver. Histopathological analyses mainly showed interstitial pneumonia, bronchopneumonia and bronchi-associated lymphoid tissue (BALT) hyperplasia. There was a significant association between metastrongylid parasitism and BALT hyperplasia in lungs. Pathological findings of wild boars indicate that the assessed individuals were not exposed to notifiable diseases, such as CSFV, African swine fever virus and foot-and-mouth disease, which cause economic damage by non-tariff trade barriers. However, the detection of antibodies against PCV2 and M. hyopneumoniae, pathogens that impact commercial production, indicates the circulation of these agents, with frequency variation in wild populations. This shows the potential risk of pathogen transmission among domestic swine populations and free-living ones. The detection of antibodies against zoonotic agents such as HEV, IAV and Leptospira spp., other than characterizing the pathogens' circulation in these populations, suggests a potential risk to public health and pig farming, depending on the interactions established with the environment, humans and domestic swine.

Simple, Low-Cost and Long-Lasting Film for Virus Inactivation Using Avian Coronavirus Model as Challenge.

The COVID-19 infection, caused by SARS-CoV-2, is inequitably distributed and more lethal among populations with lower socioeconomic status. Direct contact with contaminated surfaces has been among the virus sources, as it remains infective up to days. Several disinfectants have been shown to inactivate SARS-CoV-2, but they rapidly evaporate, are flammable or toxic and may be scarce or inexistent for vulnerable populations. Therefore, we are proposing simple, easy to prepare, low-cost and efficient antiviral films, made with a widely available dishwashing detergent, which can be spread on hands and inanimate surfaces and is expected to maintain virucidal activity for longer periods than the current sanitizers. Avian coronavirus (ACoV) was used as model of the challenge to test the antivirus efficacy of the proposed films. Polystyrene petri dishes were covered with a thin layer of detergent formula. After drying, the films were exposed to different virus doses for 10 min and virus infectivity was determined using embryonated chicken eggs, and RNA virus quantification in allantoic fluids by RT-qPCR. The films inactivated the ACoV (ranging from 103.7 to 106.7 EID50), which is chemically and morphologically similar to SARS-CoV-2, and may constitute an excellent alternative to minimize the spread of COVID-19.

Effect of time of therapy with wild-type lytic bacteriophages on the reduction of Salmonella Enteritidis in broiler chickens.

Salmonella Enteritidis remains a leading cause of human foodborne disease, mostly associated with the consumption of contaminated poultry products. To more strategically implement a phage therapy scheme for S. Enteritidis control in broilers, a cocktail containing three wild-type lytic bacteriophages (LBs) previously isolated from chickens was evaluated shortly and later after a challenge. Genomic characterization, lytic spectrum and in vitro efficacy were determined for each studied LB. In independent trials, broilers challenged with S. Enteritidis on day of hatch received phage therapy from 6 to 10 days of age (early treatment), and from 31 to 35 days of age (later treatment). S. Enteritidis analyses were performed before treatment and at 1, 4, 7 and 10 days post-treatment (dpt) in both trials. Partial DNA sequence analysis of each LB revealed close similarity to the Ackermannviridae family. LBs lysed different Salmonella enterica serovars, while other tested bacteria were refractory. An in-vitro reduction of 1.49, 0.65 and 0.58 log10 CFU/mL in S. Enteritidis number was obtained after co-incubation for 3 h with each LB. Both in vivo trials showed a significant reduction in the average number of intestinal S. Enteritidis calculated after phage therapy compared with controls. However, the highest efficiency was found in the later therapy, which resulted in a reduction of 1.08 log10 CFU/g in the average from 4 to 10 dpt, showing potential for future use as a pre-harvest strategy to reduce the S. Enteritidis intestinal colonization in broilers on farms.

Detection of Toxoplasma gondii infection in feral wild boars (Sus scrofa) through indirect hemagglutination and PCR / Detecção de infecção por Toxoplasma gondii através da hemaglutinação indireta e PCR em javalis (Sus scrofa) de vida livre

ABSTRACT: Wild boars (Sus scrofa) have become an important invasive species in all Brazilian regions. Increase in their population causes damage to rural properties, as they invade and destroy crops. To protect their crops and farm animals, producers hunt wild boars and often consume the product without any sanitary control, becoming exposed to various types of pathogens, including Toxoplasma gondii. Sanitary evaluations of these animals are scarce, especially in relation to the protozoan T. gondii. This study aimed to evaluate the occurrence of this pathogen in wild boars in Brazil. We analyzed 122 blood samples from wild boars (blood clots and serum), collected between 2014 and 2016 in five Brazilian states, using polymerase chain reaction (PCR) and indirect hemagglutination (IH) techniques. In total, 33 (27%) samples were positive by at least one test, 16 (13.1%) were positive by PCR, 19 (15.6%) were positive by IH, and only 2 (1.6%) were positive by both tests. The lack of sanitary management of feral animals increases the incidence of infections, and the consumption of raw or inadequately cooked meat may become a potential source of infection for humans in Brazil.

RESUMO: Os javalis (Sus scrofa) tornaram-se uma importante espécie invasora em todas as regiões do Brasil. Com o aumento de sua população causam danos em propriedades rurais, invadindo e destruindo lavouras. Como alternativa para proteger suas culturas e criações, os produtores os caçam e muitas vezes consomem o produto sem qualquer tipo de controle sanitário, expondo esses consumidores a diversos tipos de patógenos, entre eles o Toxoplasma gondii. Avaliações sanitárias destes animais são escassas, principalmente, em relação ao protozoário T. gondii. Este trabalho teve como objetivo avaliar a ocorrência deste patógeno em javalis de vida livre no Brasil. Foram analisadas 122 amostras de sangue de javalis (coágulos sanguíneos e soro), coletadas entre os anos de 2014 a 2016, de cinco estados do Brasil, através da técnica da Reação em Cadeia da Polimerase (PCR) e da técnica de hemaglutinação indireta (HI). No total, 33 (27%) amostras foram positivas em pelo menos um teste, sendo 16 (13,1%) na PCR e 19 (15,6%) na IH e apenas 2 (1,6%) em ambos os testes. A falta de manejo sanitário dos animais ferais aumenta a incidência de possíveis infecções e o consumo da carne crua ou sem cocção adequada pode vir a ser potencial fonte de infecção para humanos.

Impact of treatments for recycled broiler litter on the viability and infectivity of microorganisms.

The microbiological risk of recycled litter depends on the efficacy of the management system applied to inactivate residual microorganisms and preserve the health of the successive broiler flock. This study aimed to assess the viability and infectivity of the Newcastle Disease Virus (NDV), Infectious Bursal Disease Virus (IBDV) and Salmonella Heidelberg in recycled litter exposed to different treatments. The litter was contaminated with microorganisms and submitted to the treatments (T): T1: shallow fermentation; T2: quicklime (calcium oxide); T3: shallow fermentation followed by addition of quicklime; T4: no treatment. Sentinel chicks housed on the treated litter showed that T1 and T3 inactivated residual IBDV. Analysis of the litter subjected to T1 also showed reduced levels of total enterobacteria. T2 was not able to reduce the microorganisms assessed and its association with T1 (T3) failed to enhance the effect of the treatment. NDV did not survive in the broiler litter, regardless of the treatment applied, and it was also not detected in the sentinel chicks. S. Heidelberg remained viable in the litter submitted to all studied treatments, being isolated from the sentinel chicks of all the experimental groups. The antimicrobial activity of T1 and T3 was associated to higher ammonia contents in the broiler litter. The results indicate that the shallow fermentation treatment is efficient for controlling residual IBDV and total enterobacteria in the recycled litter.

Early immune responses and development of pathogenesis of avian infectious bronchitis viruses with different virulence profiles.

Avian infectious bronchitis virus (IBV) primarily replicates in epithelial cells of the upper respiratory tract of chickens, inducing both morphological and immune modulatory changes. However, the association between the local immune responses induced by IBV and the mechanisms of pathogenesis has not yet been completely elucidated. This study compared the expression profile of genes related to immune responses in tracheal samples after challenge with two Brazilian field isolates (A and B) of IBV from the same genotype, associating these responses with viral replication and with pathological changes in trachea and kidney. We detected a suppressive effect on the early activation of TLR7 pathway, followed by lower expression levels of inflammatory related genes induced by challenge with the IBV B isolate when compared to the challenge with to the IBV A isolate. Cell-mediated immune (CMI) related genes presented also lower levels of expression in tracheal samples from birds challenged with B isolate at 1dpi. Increased viral load and a higher percentage of birds with relevant lesions were observed in both tracheal and renal samples from chickens exposed to challenge with IBV B isolate. This differential pattern of early immune responses developed after challenge with IBV B isolate, related to the downregulation of TLR7, leading to insufficient pro-inflammatory response and lower CMI responses, seem to have an association with a most severe renal lesion and an enhanced capability of replication of this isolate in chicken.

Anticorpos contra vírus de galinha em cracídeos / Detection of antibodies against commercial poultry viruses in cracids

Os cracídeos são Galliformes silvestres das Américas. Com o objetivo de investigar a presença de anticorpos contra vírus de galinhas em cracídeos, foram coletadas 51 amostras de soro de 10 diferentes espécies dessas aves. Esses animais eram mantidos em criatórios conservacionistas e zoológicos nos Municípios de Santa Maria, Soledade, Passo Fundo, Sapucaia, Gravataí, Viamão e Três Coroas, Estado do Rio Grande do Sul, Brasil. Anticorpos neutralizantes foram detectados em 5,9 por cento (3/51) do total de amostras testadas contra o vírus da bronquite infecciosa das galinhas, 15,7 por cento (8/51) contra o reovírus aviário e 35,3 por cento (18/51) contra o vírus da doença infecciosa da bolsa. Todas as amostras foram negativas para o vírus da bouba aviária no teste de IDGA. A detecção de anticorpos para vírus de aves comerciais sugere que os cracídeos podem ser susceptíveis à infecção por esses vírus.

The cracids are wild Galliformes native from the Americas. Fifty one serum samples were collected from individuals of 10 different species of cracids in order to obtain information regarding to the antibody status of different viruses. These birds were kept in shelters and zoos localized in Santa Maria, Soledade, Passo Fundo, Sapucaia, Gravataí, Viamão and Três Coroas counties, in the Rio Grande do Sul State, Brazil. Neutralizing antibodies were detected in the individuals serum from different species specific referring to infectious bronchitis virus in 5.9 percent (3/51) of the samples, to avian reovirus in 15.7 percent (8/51) and, to infectious bursal disease virus in 35.3 percent (18/51). All samples were negative for fowlpox virus, as measured by IDGA test. The detection of commercial poultry viruses antibodies suggests that cracids could be susceptible to infection by those viruses.

Anticorpos contra vírus em galinhas de terreiro do Estado do Rio Grande do Sul, Brasil / Antibodies against avian viruses in backyard poultry from the Rio Grande do Sul State, Brazil

No Brasil, a população de aves conhecida como galinhas de terreiro encontra-se fora do sistema de biosseguridade aplicada às criações comerciais. Para investigar a presença de anticorpos contra alguns vírus específicos nesta população, foram coletadas amostras de sangue de 867 aves não-vacinadas em 60 propriedades de 22 municípios do Estado do Rio Grande do Sul, Brasil. O soro foi testado para a presença de anticorpos contra o vírus da bronquite infecciosa das galinhas (IBV), reovírus aviário (ARV) e o vírus da doença infecciosa da bolsa (IBDV) pela técnica de soroneutralização. Anticorpos contra IBV foram detectados em 65 por cento (564/867) das amostras, contra ARV em 21,6 por cento (187/867) e contra IBDV em 80,2 por cento (695/867) das aves. Todas as propriedades avaliadas apresentavam uma ave positiva para anticorpos contra IBV e IBDV e 88,3 por cento delas eram positivas para ARV. Os resultados demonstram que esses vírus estão presentes em galinhas de terreiro nas criações avícolas não-industriais da região central do Estado. Os resultados indicam a necessidade de um programa de vigilância permanente nessa população e ainda indicam a necessidade de avaliar o impacto destas infecções nos próprios plantéis e o risco associado à transmissão destas às criações comerciais.

The backyard poultry are not included in the biosecurity system applied in commercial flocks in Brazil. To investigate the presence of antibodies to specific viral pathogens in this population, blood samples were collected from 867 non-vaccinated birds, from 60 flocks in 22 counties of the Rio Grande do Sul State, Brazil. The samples were tested to detect antibodies against infectious bronchitis virus (IBV), avian reovirus (ARV) and infectious bursal disease virus (IBDV), through the virus neutralization test. Antibodies to IBV were detected in 65 percent (564/867), against ARV in 21.6 percent (187/867), and against IBDV in 80.2 percent (695/867) of the samples. All the flocks had chickens positive to IBV and IBDV antibodies, and 88.3 percent of them harbored antibodies to ARV. The results show the presence of these viruses in backyard poultry from the central region of the State. It also indicates the need for additional studies aimed to evaluate the real importance of these infections for this type of flocks.

Development and standardization of an indirect ELISA for the serological dianosis of classical swine fever

Um ensaio imunoenzimático do tipo ELISA indireto (ELISA-I) foi desenvolvido e padronizado para o diagnóstico sorológico de peste suína clássica. Na comparaçäo foram utilizadas novecentas e trinta e sete amostras de soros suínos, as quais foram testadas pelo teste de soroneutralizaçäo seguido de revelaçäo por imunoperoxidase (NPLA), tomado como padräo, resultando em 223 amostras positivas e 714 negativas. Em relaçäo ao NPLA, o ELISA-I apresentou sensibilidade de 98,21 por cento, especificidade de 92,86 por cento, valor preditivo positivo de 81,11 por cento, valor preditivo negativo de 99,4 por cento e precisäo de 94,1 por cento. A análise estatística dos resultados revelou uma correlaçäo muito forte (r=0,94) entre os dois testes. Quando comparado com um "kit" de ELISA disponível comercialmente, a performance de ambos em relaçäo ao NPLA foi similar. Concluiu-se que o ELISA-I é um teste apropriado para triagem em larga escala de soros para a detecçäo de anticorpos contra o Vírus da Peste Suína Clássica (VPSC), embora näo seja capaz de diferenciar entre anticorpos induzidos pelo VPSC ou outros pestivírus