RESUMO

Infectious laryngotracheitis (ILT) is a severe respiratory disease, which causes high morbidity and mortality in affected birds. In our study, ILT were reported in 42 farms from nine governates over two years (2018–2020) that showed clinical signs of ILT including dyspnea, blood expectoration of, excessive lacrimation, rattling, conjunctivitis. The disease affected different chicken breeds and age groups despite vaccination with licensed and commonly used vaccines. Samples of larynx, trachea, lungs and air sacs were examined and collected for histopathological, ultrastructural, immunohistochemical examination and molecular detection. Gross examination of laryngeal and tracheal lumen revealed different types of exudate varied from catarrhal to fibrinonecotric, also pneumonia and airsacculitis were detected. Histopathological examination showed different alternation in larynx, trachea, lung and air sac as characteristic syncytial cells containing intranuclear inclusion body hanged in fibrinoheterphilic exudate that precent in laryngeal, tracheal, bronchial and parabronchial lumen and air sacs. Tracheal lesion scoring system was used to categorize the severity of lesion in different governates. Tracheal lesion score showed that 6.02%, 26.5%, 43.3% of the birds exhibited mild, moderate, and severe changes, respectively, while 24.18% of the birds exhibited very severe changes. Furthermore, severe cases were related to the Qalyubia , Fayoum then Sharkia Governorate. Moreover, immunohistochemistry was used to detect viral particles in syncytial cells, inflammatory cells beside epithelium of trachea and lung. Transmission electron microscopy enabled the detection of virus particles and demonstrated that heterophils could be infected. PCR targeting a region in the thymidine kinase gene and glycoprotein gJ gene confirmed the presence of infectious laryngotracheitis ILT virus-specific DNA. In conclusion, anatomopathological, immunohistochemical, molecular and ultrastructural findings showed increased of ILTV severity in Egypt. Larynx, trachea, lungs and air sac should be collected and examined that aid in diagnosis. Importance of good biosecurity level to be considered.

Assuntos

RESUMO

Infectious laryngotracheitis (ILT) is a severe respiratory disease, which causes high morbidity and mortality in affected birds. In our study, ILT were reported in 42 farms from nine governates over two years (2018–2020) that showed clinical signs of ILT including dyspnea, blood expectoration of, excessive lacrimation, rattling, conjunctivitis. The disease affected different chicken breeds and age groups despite vaccination with licensed and commonly used vaccines. Samples of larynx, trachea, lungs and air sacs were examined and collected for histopathological, ultrastructural, immunohistochemical examination and molecular detection. Gross examination of laryngeal and tracheal lumen revealed different types of exudate varied from catarrhal to fibrinonecotric, also pneumonia and airsacculitis were detected. Histopathological examination showed different alternation in larynx, trachea, lung and air sac as characteristic syncytial cells containing intranuclear inclusion body hanged in fibrinoheterphilic exudate that precent in laryngeal, tracheal, bronchial and parabronchial lumen and air sacs. Tracheal lesion scoring system was used to categorize the severity of lesion in different governates. Tracheal lesion score showed that 6.02%, 26.5%, 43.3% of the birds exhibited mild, moderate, and severe changes, respectively, while 24.18% of the birds exhibited very severe changes. Furthermore, severe cases were related to the Qalyubia , Fayoum then Sharkia Governorate. Moreover, immunohistochemistry was used to detect viral particles in syncytial cells, inflammatory cells beside epithelium of trachea and lung. Transmission electron microscopy enabled the detection of virus particles and demonstrated that heterophils could be infected. PCR targeting a region in the thymidine kinase gene and glycoprotein gJ gene confirmed the presence of infectious laryngotracheitis ILT virus-specific DNA. In conclusion, anatomopathological, immunohistochemical, molecular and ultrastructural findings showed increased of ILTV severity in Egypt. Larynx, trachea, lungs and air sac should be collected and examined that aid in diagnosis. Importance of good biosecurity level to be considered.(AU)

Assuntos

RESUMO

Infectious laryngotracheitis virus (ILTV) is the causative agent of an acute respiratory avian disease known as infectious laryngotracheitis (ILT), which has been associated with economic losses in poultry. The presence of ILTV has been widely reported in South American countries; however, only one full genomic sequence (VFAR-043 strain) has been recently published, from an outbreak in Peru. The aim of this study was to determine the genetic relationship of the Peruvian strain with other ILTV strains from different geographic regions. The phylogenetic analyses revealed a close relationship between VFAR-043 and two U.S. origin strains (1874C5 and J2) using only the whole genome, Unique Long (UL), and Unique Short (US) genomic regions. Then these three genomic sequences were compared to evaluate their genetic variations using the USDAref as a reference strain. Genetic variations such as synonymous and nonsynonymous single-nucleotide polymorphisms, insertions, deletions, and nucleotide-codon variations were identified among these three strains. Moreover, the phylogenetic tree analysis using gene sequences of the US5 and ICP4 coding regions from South American isolates showed that VFAR-043 does not have a close relationship with either the Argentinian (US5) or Brazilian (ICP4) reported sequences. However, a close relationship was observed between VFAR-043 and another Peruvian isolate (USP-81) when the ICP4 gene sequence was analyzed. All these results suggest that VFAR-043 together with 1874C5 and J2 are closely related. These findings contribute to our understanding of the epidemiology of ILTV in South America.

Evidencia filogenética de una relación genética cercana entre la cepa peruana del virus de la laringotraqueítis infecciosa aviar VFAR-043 y dos cepas de campo con origen en los Estados Unidos. El virus de laringotraqueítis infecciosa aviar es el agente causal de una enfermedad aviar respiratoria aguda conocida como laringotraqueítis infecciosa que está asociada con pérdidas económicas en la industria avícola. La presencia del virus de la laringotraqueítis infecciosa ha sido ampliamente reportada en países de América del Sur; sin embargo, solamente una secuencia genómica completa (cepa VFAR-043) ha sido publicada recientemente y obtenida a partir de un brote en Perú. El objetivo de este estudio fue determinar la relación genética de la cepa peruana con otras cepas de diferentes regiones geográficas. El análisis filogenético reveló una cercana relación entre el virus VFAR-043 y dos cepas de los Estados Unidos (18746C5 y J2) usando el genoma completo y las regiones genómicas única larga (UL) y la región genómica única corta (UC). Posteriormente, estas tres secuencias genómicas fueron comparadas con la cepa de referencia del Departamento de Agricultura de los Estados Unidos (USDAref) para evaluar sus variaciones genéticas. Variaciones genéticas como polimorfismo de nucleótido único (con las siglas en inglés SNP) tanto de tipo sinónimo y no-sinónimo, inserciones, deleciones y variación de nucleótido en un codón fueron identificadas entre estas tres cepas (VFAR-043, 18746C5 y J2). Además, el análisis de los árboles filogenéticos usando secuencias genéticas de la región codificadora de US5 e ICP4 de aislamiento sudamericanos reveló que el virus VFAR-043 no mostró relación genética cercana con secuencias argentinas (US5) ni secuencias brasileras (ICP4) que están reportadas. No obstante, se observó una relación cercana entre el virus VFAR-043 y otro aislamiento peruano (USP-81) cuando se analizó la secuencia genética del gen ICP4. Todos estos resultados sugieren que los virus VFAR-043, 1874C5 y J2 están genéticamente relacionados. Estos hallazgos contribuyen al conocimiento de la epidemiologia del virus de la laringotraqueítis infecciosa aviar en América del Sur.

Assuntos

RESUMO

Infectious laryngotracheitis is a very important respiratory disease because it causes significant economic losses in the poultry industry. The target of ILTV infections is the respiratory system, and the main organ in which the virus remains latent is the trigeminal ganglia. However, the virus has demonstrated tropism for other organs as well. The present study was conducted to determine the presence of Infectious Laryngotracheitis Virus (ILTV) in the state of São Paulo. Samples submitted to LABOR- USP during the last four years (2009-2013) analyzed by a nested/PCR technique. Out of the 682 samples from layers tested for LTIV, 12.46 % were positive, and derived from in both traditional (trachea and trigeminal ganglion) and untraditional (cecal tonsils, digestive tract and kidneys) organs utilized for ILTV diagnosis. The present work showed that ILTV is circulating in commercial layer flocks in São Paulo State, and that the LTIV is present in other organs in addition to the respiratory tract and trigeminal ganglion; however, it was not determined if the circulating virus is a vaccinal or field strain.

Assuntos

RESUMO

Infectious laryngotracheitis is a very important respiratory disease because it causes significant economic losses in the poultry industry. The target of ILTV infections is the respiratory system, and the main organ in which the virus remains latent is the trigeminal ganglia. However, the virus has demonstrated tropism for other organs as well. The present study was conducted to determine the presence of Infectious Laryngotracheitis Virus (ILTV) in the state of São Paulo. Samples submitted to LABOR- USP during the last four years (2009-2013) analyzed by a nested/PCR technique. Out of the 682 samples from layers tested for LTIV, 12.46 % were positive, and derived from in both traditional (trachea and trigeminal ganglion) and untraditional (cecal tonsils, digestive tract and kidneys) organs utilized for ILTV diagnosis. The present work showed that ILTV is circulating in commercial layer flocks in São Paulo State, and that the LTIV is present in other organs in addition to the respiratory tract and trigeminal ganglion; however, it was not determined if the circulating virus is a vaccinal or field strain.(AU)

Assuntos

RESUMO

Two different regions of the infected cell protein 4 (ICP4) gene of infectious laryngotracheitis virus (ILTV) were amplified and sequenced for characterization of field isolates and tissue culture-origin (TCO) and chicken embryo-origin (CEO) vaccine strains. Phylogenetic analysis of the two regions showed differences in nucleotide and amino acid sequences between field isolates and attenuated vaccines. The PCR-RFLP results were identical to those obtained by DNA sequencing and validated their use to differentiate ILTV strains. The approach using the sequencing of the two fragments of the ICP4 gene showed to be an efficient and practical procedure to differentiate between field isolates and vaccine strains of ILTV.

Assuntos