RESUMO
The objective of this study was to determine how cytokine transcription profiles correlate with patterns of infectious laryngotracheitis virus (ILTV) replication in the trachea, Harderian gland, and trigeminal ganglia during the early and late stages of infection after intratracheal inoculation. Viral genomes and transcripts were detected in the trachea and Harderian gland but not in trigeminal ganglia. The onset of viral replication in the trachea was detected at day one post-infection and peaked by day three post-infection. The peak of pro-inflammatory (CXCLi2, IL-1ß, IFN-γ) and anti-inflammatory (IL-13, IL-10) cytokine gene transcription, 5 days post-infection, coincided with the increased recruitment of inflammatory cells, extensive tissue damage, and limiting of virus replication in the trachea. In contrast, transcription of the IFN-ß gene in the trachea remained unaffected suggesting that ILTV infection blocks type I interferon responses. In the Harderian gland, the most evident transcription change was the early and transient upregulation of the IFN-γ gene at 1 day post-infection, which suggests that the Harderian gland is prepared to rapidly respond to ILTV infection. Overall, results from this study suggest that regulation of Th1 effector cells and macrophage activity by Th1/2 cytokines was pertinent to maintain a balanced immune response capable of providing an adequate Th1-mediated protective immunity, while sustaining some immune homeostasis in preparation for the regeneration of the tracheal mucosa.
Assuntos
Citocinas/metabolismo , Glândula de Harder/metabolismo , Infecções por Herpesviridae/veterinária , Herpesvirus Galináceo 1/patogenicidade , Traqueia/metabolismo , Gânglio Trigeminal/metabolismo , Animais , Galinhas , Citocinas/genética , DNA , Regulação da Expressão Gênica/imunologia , Genoma Viral , Glândula de Harder/virologia , Infecções por Herpesviridae/metabolismo , Infecções por Herpesviridae/virologia , Herpesvirus Galináceo 1/fisiologia , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/metabolismo , Doenças das Aves Domésticas/virologia , RNA , Organismos Livres de Patógenos Específicos , Traqueia/virologia , Transcrição Gênica , Gânglio Trigeminal/virologia , Carga Viral , Virulência , Replicação ViralRESUMO
Infectious laryngotracheitis is a highly contagious disease of chickens responsible for significant economic losses for the poultry industry worldwide. The disease is caused by Gallid herpesvirus-1 (GaHV-1) commonly known as the infectious laryngotracheitis virus. Although characterized by their potential to regain virulence, chicken embryo origin (CEO) vaccines are the most effective vaccines against laryngotracheitis as they significantly reduce the replication of challenge virus in the trachea and conjunctiva. Knowledge on the nature of protective immunity elicited by CEO vaccines is very limited. Therefore, elucidating the origin of the immune responses elicited by CEO vaccination is relevant for development of safer control strategies. In this study the transcription levels of key host immune genes (IFN-γ, IFN-ß, IL-1ß, IL-6, IL-8, IL-18) and viral genes (ICP4, ICP27, UL46, UL49), as well as viral genome loads in trachea were quantified at 6 and 12 hours post-challenge of CEO vaccinated and non-vaccinated chickens. Immediately after challenge a significant increase in IFN-γ gene expression was followed by a significant reduction in viral replication. In contrast to the rapid induction of IFN-γ, expression of the pro-inflammatory cytokines (IL-1ß, IL-6, IL-8) and type I IFN ß was either slightly reduced or remained at basal levels. These suggest that the former cytokines may not play important roles during immediate early responses induced by ILTV challenge in either vaccinated or non-vaccinated chickens. Overall, these results suggest that the rapid expression of IFN-γ may induce pathways of antiviral responses necessary for blocking early virus replication.
Assuntos
Anticorpos Antivirais/imunologia , Galinhas/imunologia , Citocinas/metabolismo , Infecções por Herpesviridae/veterinária , Herpesvirus Galináceo 1/imunologia , Doenças das Aves Domésticas/prevenção & controle , Vacinas Virais/imunologia , Animais , Galinhas/virologia , Infecções por Herpesviridae/prevenção & controle , Infecções por Herpesviridae/virologia , Herpesvirus Galináceo 1/genética , Interferon gama/metabolismo , Interleucina-6/metabolismo , Doenças das Aves Domésticas/virologia , Organismos Livres de Patógenos Específicos , Traqueia/imunologia , Traqueia/virologia , Vacinas Atenuadas , Carga Viral/veterináriaRESUMO
Shade-grown coffee plantations are often promoted as a conservation strategy for wild birds. However, these agro-ecosystems are actively managed for food production, which may alter bird behaviors or interactions that could change bird health, compared to natural forest. To examine whether there is a difference between the health parameters of wild birds inhabiting shade-grown coffee plantations and natural forest, we evaluated birds in Costa Rica for (1) their general body condition, (2) antibodies to pathogens, (paramyxovirus and Mycoplasma spp.), and (3) the prevalence and diversity of endo-, ecto-, and hemoparasites. We measured exposure to Mycoplasma spp. and paramyxovirus because these are pathogens that could have been introduced with domestic poultry, one mechanism by which these landscapes could be detrimental to wild birds. We captured 1,561 birds representing 75 species. Although seasonal factors influenced body condition, we did not find bird general body condition to be different. A total of 556 birds of 31 species were tested for antibodies against paramyxovirus-1. Of these, five birds tested positive, four of which were from shade coffee. Out of 461 other tests for pathogens (for antibodies and nucleotide detection), none were positive. Pterolichus obtusus, the feather mite of chickens, was found on 15 birds representing two species and all were from shade-coffee plantations. Larvated eggs of Syngamus trachea, a nematode typically associated with chickens, were found in four birds captured in shade coffee and one captured in forest. For hemoparasites, a total of 1,121 blood smears from 68 bird species were examined, and only one species showed a higher prevalence of infection in shade coffee. Our results indicate that shade-coffee plantations do not pose a significant health risk to forest birds, but at least two groups of pathogens may deserve further attention: Haemoproteus spp. and the diversity and identity of endoparasites.
Assuntos
Agricultura/métodos , Doenças das Aves/epidemiologia , Aves/microbiologia , Ecossistema , Árvores , Animais , Animais Selvagens/microbiologia , Animais Selvagens/parasitologia , Animais Selvagens/virologia , Avulavirus/isolamento & purificação , Aves/sangue , Aves/parasitologia , Aves/virologia , Coffea/crescimento & desenvolvimento , Conservação dos Recursos Naturais/métodos , Costa Rica , Mycoplasma/isolamento & purificaçãoRESUMO
Pathogens of free-ranging chickens create a risk of disease for wild birds, some of which migrate to the United States, as well as potential economic losses for resource-poor farmers. Free-roaming backyard chickens are commonly kept in shade-grown coffee plantations, habitats that attract large numbers of wild birds. The husbandry and pathogen prevalence of backyard chicken flocks in San Luis, Costa Rica, were investigated. Based on serologic evidence, Newcastle disease virus, infectious laryngotracheitis virus, infectious bronchitis virus, chicken anemia virus, and infectious bursal disease virus, as well as both Mycoplasma gallisepticum and Mycoplasma synoviae, appear to be significant diseases of this population, and thus, we consider these backyard chickens potential reservoirs for these diseases. There was no evidence of avian influenza. Interviews, clinical examinations, and microscopic examination of tissues led us to believe that poxvirus is also a significant cause of morbidity and mortality in these chickens. We found that Escherichia coli isolates were resistant against tilmicosin, tetracycline, ampicillin, amoxicillin with clavulanic acid, ticarcillin, and cephalothin, and contained genes considered responsible for conferring tetracycline resistance. Additionally, although production was not measured, we suspect that husbandry and lack of preventative medicine are directly related to the diseases reported, all of which negatively affect production.