Poultry Respiratory Syndrome. Etiology, Diagnostics, Measures of Control and Prevention

2023

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Studies carried out in many countries of the world demonstrate considerable variability in the virulence properties of pasteurellosis. The variety of antigenicity and toxicity serovars of the pathogen determines a number of specific features of display of poultry pasteurellosis, especially in associated infections when several causative agents of infectious diseases of bacterial and/or viral etiology circulate in one farm. In mixed infections, birds show a variety of clinical signs, most notably a respiratory syndrome characterized by respiratory involvement (sinusitis, conjunctivitis, laryngitis, tracheitis, bronchitis, pneumonia, and aerosacculitis) and tissue swelling in the suborbital sinuses, intermandibular spaces, and ear flaps.This situation makes it difficult to timely and promptly conduct effective therapeutic and anti-epizootic measures. However, it is necessary to identify the etiology of the disease as soon as possible, methodically and comprehensively, taking into account epizootic data, clinical signs, pathological anatomical changes and with obligatory confirmation by laboratory tests.At present time laboratory methods for diagnostics of avian pasteurellosis are regulated by Methodical instructions (MI) on laboratory diagnostics of pasteurellosis of animals and birds approved by the Chief Veterinary Department on August 20, 1992 № 22-7/82.According to the approved MI, the laboratory diagnosis of avian pasteurellosis includes microscopy of smears and fingerprints, isolation of pasteurella cultures and their identification, and, if necessary, bioassaying.It should be noted that the laboratory diagnosis of pasteurellosis according to the MI is a laborious and time-consuming process.Apart from the methods described in the MI, the serological method - enzyme immunoassay (ELISA) and molecular biological method - polymerase chain reaction (PCR) are currently widely and successfully used in laboratory practice for diagnosis of avian pasteurellosis, which are not reflected in the approved MI, but allow relatively simple and rapid reliable results.

Section: рефератunclassified

Modern approaches in the diagnosis of avian Pasteurellosis

2023

jour

“…При патологоанатомическом вскрытии обнаруживают отёчность соединительной ткани головы, серозно-гнойные воспаления носовых ходов и инфраорбитальных синусов, а при осложнении вторичной микрофлорой -аэросаккулиты, перикардиты, энтериты и поражения репродуктивных органов [1,4,6].…”

Section: рефератunclassified

“…Метапневмовирусная инфекция птиц (МПВИ) -заболевание кур, фазанов, уток и индеек, характеризующаяся воспалительными процессами дыхательных органов. Экономический ущерб, причиняемый МПВИ, складывается из ухудшения конверсии корма, снижения среднесуточных привесов, потери яичной продуктивности, затрат на проведение общих и специфических ветеринарно-санитарных мероприятий [1,4].…”

Section: Introductionunclassified

“…

Основные риски в искусственном воспроизводстве водных биоресурсов обусловлены болезнями выращиваемых объектов. К значительным биологическим и экономическим потерям приводят заразные-инфекционные и инвазионные заболевания [4]. В данной статье представлены материалы лабораторных исследований на паразитарную безопасность рыбоводных хозяйств Псковской области за 2020-2021 годы.Своевременная диагностика позволяет быстро остановить эпизоотический процесс.

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unclassified

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Metapneumovirus infection in poultry

2022

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Today's high performance in the industrial poultry industry would not have been possible without the focused specialization of production and the use of highly productive poultry crosses. Therefore, the organization of modern poultry farming used simultaneously with high productivity indicators leads to a decrease in natural resistance and an increase in the susceptibility of birds to various pathogens of infectious diseases transmitted aerogenically, which is accompanied by the manifestation of respiratory syndrome in birds. One of the key reasons for the development of respiratory syndrome is the circulation of pneumovirus in the herd, which is especially dangerous for meat farms, since in broiler chickens the disease proceeds in a more severe form compared to poultry crosses.Avian metapneumovirus infection causes significant economic damage to poultry farming, which consists of losses from a decrease in safety and productivity, as well as the cost of health and preventive measures.4 subtypes of MPV are officially known, although recent publications have reported of two new pneumoviruses, GuMPV and AMPV PAR-05 isolated from the seagull in North America.The diversity of pathogen subtypes and differences in virulence properties of metapneumovirus create difficulties both in the prevention of this disease and in its diagnosis.Difficulty of metapneumovirus isolation from the examined material is caused by the short period of virus persistence in the organs of birds.The most effective method of controlling avian MPVI is vaccination.

“…Экономический ущерб от МПВИ складывается из потерь, связанных со снижением Key words: mathematical theor y of epidemics/epizootics, deter ministic and stochastic models, infectious diseases, risks, forecasting Ключевые слова: Метапневмовирус птиц, МПВ подтипы А и В, ПЦР, мультиплексная диагностика. сохранности и продуктивности птицы, а также из материальных затрат на проведение лечебнооздоровительных и профилактических мероприятий [1,2,5,6].…”

Section: Introductionunclassified

Diagnosis of avian metapneumovirus infection using multiplex PCR

Semina

2023

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Avian metapneumovirus infection causes significant economic damage to poultry farming, which consists of losses from a decrease in safety and productivity, as well as the cost of health and preventive measures.The causative agent of the disease is avian metapneumovirus family Paramyxoviridae subfamily Pneumovirinae genus Metapneumovirus. The viral genome consists of 8 genes encoding 9 proteins: N-nucleoprotein, P-phosphoprotein, Mmatrix protein, F-fusion protein, M2 (M2-1,M2-2) - elongation/transcription factor, SH-(small) hydrophobic protein, Gglycoprotein, L-(large) polymerase. The virus lacks non-structural NS1 and NS2 proteins that counteract interferon.Based on the nucleotide seguence of the variable glycoprotein G gene, avian metapneumovirus was classified into four 4 subtypes of MPV are officially known, although recent publications have reported of two new pneumoviruses, GuMPV and AMPV PAR-05 isolated from the seagull and parrot in North America.The diversity of pathogen subtypes and differences in virulence properties of metapneumovirus create difficulties both in the prevention of this disease and in its diagnosis.The complexity of isolating the metapneumovirus from the test material is due to the short period of persistence of the virus in the organs of birds. It is possible to isolate the RNA of the causative agent of MPVI by the molecular biological method within 17-19 days after infection. The aim of our work was development and testing of primers and probes for the simultaneous detection and differentiation of avian metapneumovirus subtypes A and B by PCR with real-time fluorescence detection, with high specificity.Using vaccine strains 8544 and VC-03, the conditions for PCR were selected according to the composition of the PCR mixture and the annealing temperature of primers and probes. During PCR, we recorded the fluorescence signal through the FAM channel for cDNA obtained from the 8544 vaccine strain, and through the HEX channel for the VC-03 vaccine strain. The specificity of the developed primers and probes was also tested in studies with heterogeneous viruses such as Newcastle disease, classical and variant strains of chicken infectious bronchitis virus, and with bird DNA.The studies conducted to determine the specificity of the primers selected by us for multiplex PCR diagnostics make it possible to simultaneously specifically detect subtypes A and B of the causative agent of MPVI in birds in real time using different fluorescence channels, while other non-target respiratory pathogens were not observed.