Infected Flocks Research Articles

First Seroprevalence Survey of Avian Reovirus in Broiler Breeders Chicken Flocks in Morocco.

Avian reovirus (ARV) is a prevalent infectious agent that has the potential to cause respiratory and gastrointestinal illnesses in poultry, leading to substantial financial losses in the poultry sector. Until now, there have been no investigations conducted to examine the epidemiological status of ARV infections in Morocco. The aim of this study was to investigate the seroprevalence of ARV infections with respect to area, types of chickens (broiler breeder, and broiler), vaccination status, and age of chickens. A total of 826 serum samples were collected from 36 broiler and broiler breeder flocks, with 14 of them being unvaccinated, fromsix different regions of Morocco, namely Casablanca-Settat, Rabat-Salé-Kénitra, Tanger-Tétouan-Al Hoceïma, Oriental, Marrakech-Safi, and Fez-Meknès between 2021 and 2022.These serum samples were screened using a commercial indirect ELISA ARV antibody test kit (IDEXX REO). The study found that all tested flocks were positive for ARV-specific antibodies, indicating that the virus was present in these flocks. Out of the 826 serum samples tested, 782 were positive for ARV-specific antibodies. The overall prevalence of ARV infections in breeder and broiler flocks was calculated to be 94.6% ± 0.78. To summarize, the current study provides evidence of the widespread distribution of ARV infections in Morocco, suggesting that the poultry industry in the country is highly infected with ARV.

An animal-friendly collection of samples from the upper respiratory tract via drinker-swabs for the detection of avian influenza (H5N1) in poultry flocks

To take tracheal swabs from poultry flocks, for detection of avian influenza viruses is time-consuming and involves a high workload for the staff and a lot of stress for the sampled animals. Therefore, an animal-friendly and at the same time reliable method of collected of samples from poultry flocks is needed. A simple method would be a significant improvement in the control of avian influenza, especially in poultry-intensive regions. Swab samples in/on drinkers can easily be taken. When taking water, every animal with a respiratory infection leaves small amounts of its respiratory secretions (mucus) in/on the drinkers. Even before the first clinical signs appear in a flock, the influenza virus is already in small amounts of mucus particle in the drinkers present. By sampling swabs in/on many drinkers in the barn these smallest amounts of respiratory murus from infected birds in the flock can be detected by PCR-technic. In contrast to the faecal samples, the samples from the drinkers contain only a small amount of DNA and RNA from microorganisms
 The PCR results from this field study allow the conclusion that swabs from the drinkers in the barn yield very reliable and very important information about the presence of avian influenza viruses in a poultry population. However, it is important to take swab samples from many drinkers in the barn. An Influenza monitoring with swab samples from drinkers is rapid, sensitive, specific, reliable, inexpensive and can be taken easily by individuals, regardless of the age and the number of birds in the flock. Detecting the avian influenza virus in infected flocks with swab sampling in/on drinkers is an animal-friendly process with an improvement in the statistical significance of the infection status of a flock.

The Prevalence and Molecular Distinguishing of Brucella melitensis Rev1 Strain among Field Isolates the Brucella from Sheep and Goat Milk through PCR-RFLP Analysis of omp2 Gene Polymorphism

The present study was undertaken to characterize the prevalence and molecular distinguishing of Brucella melitensis field and vaccine Rev1 strains isolated from milk among the sheep and goat population. The study was carried out on flocks of sheep and goats suffering from Brucella infection outbreaks. A total of 171 milk samples were collected from different districts of the West Bank, part of Palestine, and isolated on Brucella agar. 86 cultures were confirmed by standard biochemical methods and screened for Brucella melitensis 16M of IS711 element by a conventional PCR technique. All these samples were also amplified for the omp2 gene to identify differences between field and Rev 1 strains in an infected flock. The results obtained from the PstI restriction enzyme pattern revealed that only 2 (4.5%) samples have specific polymorphism accomplished with the Brucella melitensis Rev1 strain. All other samples were restricted according to the Brucella melitensis 16M polymorphism pattern and originated from nonvaccinated flocks. Despite the adverse side effects of the Brucella melitensis vaccine, only a well-organized whole-flock vaccination and awareness campaign may inhibit the virulence of the field strain and, subsequently, reduce the prevalence of brucellosis infection among animals and humans in Palestine.

Analysis of protein-protein interaction network based on altered genes expressed in lung tissue for avian influenza disease

The spread of bird flu disease with high mortality, reduced egg production and forced killing of infected flocks has a devastating effect on the poultry industry. Based on the central protein, the virus is divided into three subgroups A, B, and C. Influenza type A virus is very common. This virus can infect different species of mammals and birds, and it is more pathogenic than influenza B and C, and it causes epidemics of different severities almost every year. Breeding goals to maintain the health of animals lead to the well-being of animals and prevent economic losses. The purpose of this research was to use biological network analysis method to identify new key markers involved in bird flu disease. In this study, in order to quickly obtain the most important genes involved in this disease, gene expression microarray data related to the lung tissue of chickens infected with the virus was prepared from the GEO site with the accession number GSE53931. The protein-protein interaction network was drawn by Cytoscape software. Protein complexes were analyzed using MCODE. Three protein complexes were extracted. The seed proteins in the complexes include RPL10A, NOB1, and MSH4, which were introduced as key markers, as well as NEB, RPF1, CSRNP1, RNF146, and RPL18A genes with the lowest level of expression and SLC6A20, PLN, SLC17A8 ,NOXO1 and TMEM179 gene with the highest level of expression in the present study. Most of the genes are involved in the transcription, replication, translation of the gene in the influenza virus. Network-based analyzes can detect effective genes and functional modules, which can significantly help in identifying regulatory factors and biological processes involved in the response to avian influenza, and subsequently, better control of the disease.

First detection of FAdV serotype 8b associated with Inclusion Body Hepatitis in broiler flocks in the southern part of Iraq during, 2022-2023

Field observations reported many outbreaks of IBH infection in poultry flocks in different regions of Basra province leading to high economic losses, and the diagnosis of the disease is based on clinical signs and gross pathological lesions. Little information on FAdV recently circulating in the southern part of Iraq; thus, partial sequencing of hexon gene of four FAdV has been detected in the present study during the period between mid-2022 to the beginning of 2023 from various FAdV outbreaks in commercial broiler farms in southern parts of Iraq. The results showed the four Iraqi field strains of FAdV were closely related and shared a high identity of 100% to each other and to previous Iraqi strains from the northern part of Iraq. Phylogenetic analysis indicated that the four viruses obtained from this study and two additional viruses from Ninawa province are classified as serotype 8b of FAdV group E, as a predominant serotype related to inclusion body hepatitis, and clustered along with the same 8b serotype of FAdV circulating in Indonesia, Turkey, and Israel. The results provided useful genetic information on FAdV that recently reemerged in Iraq in 2022 and 2023 and might assist in the production of a local vaccine for FAdV serotype 8b.

Occurrence and phylogenetic analysis of fowl adenovirus E in broiler flocks from Gaza Strip Palestine.

Inclusion-body hepatitis (IBH) and hydropericardium syndrome (HPS) are highly infectious diseases caused by fowl adenoviruses (FAdVs). IBH and HPS cause major economic losses in poultry production. IBH is caused by multiple FAdV serotypes such as FAdV-11, FAdV8a, and FAdV8b; while HPS is mainly caused by the FAdV-4 serotype. In 2018, we detected FAdVs in West Bank - Palestine for the first time. This study aims to monitor the emergence of new FAdVs in broiler farms in Gaza Strip-Palestine in 2022. The clinical signs, necropsy, and histopathological findings associated with IBH in the suspected birds were recorded. Polymerase chain reaction (PCR) was performed using primers matching the virus-encoded L1 loop of the hexon gene. The sequences of the L1 loop were analyzed and a phylogenetic tree was constructed and compared with the related FAdV field isolates and reference strains from different regions of the world available in GenBank. The infected broiler displayed FAdVs-induced clinical symptoms and pathological lesions with mortality rates ranging from 20-46%. The L1 loop sequences from the infected flocks were submitted to GenBank with accession numbers ON638995, ON872150, and ON872151. The identified L1 loop gene has high nucleotide homology (96.7-97.9%) to the highly pathogenic FAdV E serotype 8b strain FAdV_isolate_04-53357-122_Canada_2007 (GenBank: EF685489) and 94.5-94.6% to FAdV_10_Belgium_2010 isolate 11-15941 (GenBank: AF339924.1). Furthermore, the phylogenetic analysis indicated that they belong to FAdV-E serotype 8b. Our study reports the emergence of FAdV-E causing IBH disease in broiler chickens for the first time in Gaza in Palestine.

Pathology and Epidemiology of Fungal Infections in Layer Chicken Flocks

Fungal infections have a key effect on the commercial poultry production and welfare. Infections caused by fungi and their food contaminants are zoonotic and influence food safety. Eggs and cooked meats remain major public health concerns. Therefore, this research is aimed at examining the pathology and understanding the epidemiology of fungal infection in layer chicken flocks. The study was carried out on twenty-layer flocks from Kafrelsheikh Governorate, Egypt, from January 2019 to December 2020. In total, 600 samples were collected from 100 healthy and diseased layer chickens from different organs (skin, liver, lung, kidney, spleen, and ovary). In this work, we present the clinical and pathological characteristics of some fungal pathogens (Aspergillus spp. and Fusarium spp.) in layer chicken flocks, as they are responsible for reducing the egg production. In total, 19 fungal strains were isolated from individual chickens, and these were analysed to determine the fungal species. The total proportion of fungal infections at the farm level was (3/20) 15%. The main clinical signs were emaciation and mortalities that reached 4.34 % ± 0.84 . We report the first isolation of Aspergillus piperis and Fusarium species from the ovary of poultry, which is the main reason for egg retention and multiple numerous nodules of occasional caseating centers in layer ovaries. The histopathological findings of Aspergillus infection are indicated by the presence of branched hyphae that tend to be numerous and progressive. Furthermore, we found spherules with multiple endospores of Fusarium spp. in the ovaries. Morphological and molecular identification and analysis were performed to confirm the etiological agents.

Relationship between Vaccine Application and Climate Factors in Sheep and Goat Farms in Greece.

The objectives of the present study were (a) to evaluate the importance of climate-related variables in the vaccination patterns applied in sheep and goat farms in Greece and (b) to assess potential interactions between these factors and previously established important health management- and human resources-related factors applied in the farms. Vaccination patterns against chlamydial abortion, clostridial infections, contagious agalactia, contagious ecthyma, foot-rot, paratuberculosis, pneumonia or staphylococcal mastitis were assessed. Climatic variables (2010-2019 and 2018-2019) were obtained for 444 locations with small ruminant farms throughout Greece. Patterns of vaccine administration in the farms were obtained through interviews with farmers. The following nine outcomes were considered: 'vaccination against chlamydial abortion', 'vaccination against clostridial infections', 'vaccination against contagious agalactia', 'vaccination against contagious ecthyma', 'vaccination against foot-rot', 'vaccination against paratuberculosis', 'vaccination against bacterial pneumonia', 'vaccination against staphylococcal mastitis' and 'total number of optional vaccines administered'. Univariable and multivariable analyses were first performed to establish associations of each of the above outcomes with climatic variables. Then, the same approach was employed to assess the importance of climatic variables against health management- and human resources-related factors in the administration of vaccines in the farms of the study. Climatic variables had a higher association with vaccinations against infections in sheep flocks (26 associations) than in goat herds (9 associations) (p = 0.002) and in farms with semi-extensive or extensive management (32 associations) than in farms with intensive or semi-intensive management (8 associations) (p < 0.0001). In 26 cases (38.8% of all analyses evaluated), the climatic variables overshadowed the management- and human resources-related variables assessed as significant predictors for vaccination. In most cases, these referred to sheep flocks (nine cases) and farms with semi-extensive or extensive management (eight cases). For all eight infections, there were changes in the climatic variables found to be significant predictors from the 10-year dataset to the 2-year dataset. The results indicated that, in some cases, climate factors overshadowed factors traditionally considered for the formulation of vaccination programs. This points out the significance of taking into account climate conditions in the health management of small ruminant farms. Future studies can be focused on formulating vaccination programs in accordance with climate factors and also on setting the optimum season(s) for vaccination of animals based on the circulation of the pathogens, the risks for the development of diseases and the stage within the annual production cycle of the animals.

The detection of fowl adenovirus in chickens with hydropericardium syndrome in Isfahan and Charmahal-Va-Bakhtiyari provinces, Iran

The hydropericardium in chickens is most common in Isfahan and Chcharmahal-va-Bakhtiyari, Iran. For this, the study was achieved for investigation of adenovirus role in induction of hydropericardium in these regions. In this study, 20 broiler flocks suspected to hydropericardium were sampled from hydropericardium fluid. Then, DNA was extracted and amplified by specific primers. The amplified fragment for detection of AV was 896 bp. The results showed that 10 in 20 flocks, and 47 in 200 samples were positive to AV. The results revealed that most of infected flocks were more than 30 days old. In this study, the correlation between infectivity to adenovirus and husbandry system were not significant. The infectivity rate in Isfahan and Chaharmahal-va-Bakhtiyari was not significant. Therefore, in addition to high altitude, adenovirus infection can play a role in increasing the prevalence of hydropericardium in these areas.

Chicken Astro virus (CAstV): Isolation and characterization of new strains in broiler flocks with poor performance

Chicken astroviruses (CAstV) were associated with retarded growth, enteritis, kidney diseases, and white chick syndrome. In the current study, we aimed to evaluate the effect of CAstV infection on growth, performance, and gross and histopathological picture of commercial chicken flocks suffering increased culling rate and decreased performance. Samples were collected for virus isolation, identification, and sequencing on day one, 15 days, and 30 days of age. Body weight, feed conversion rate, and mortality rates were determined. A gross examination was performed, and tissue samples from the liver, intestine, kidneys, heart, and lungs were kept in formalin for histopathological evaluation. Embryos inoculated with CAstV revealed dwarfism, and edema. The cytopathic effect on CAstV inoculated cells included aggregation,, and sloughing. The isolated Egyptian isolates shared the highest nucleotide homology (93%) with the Korean isolate Kr/ADL102655-1/2010 and showed the most distant relation to the Indian isolate Indovax/APF/1319 with 82–83% homology. Body weight exhibited significant reduction with a decrease in feed conversion rate in CAstV infected flocks. Gross examination of CAstV-infected chickens revealed white feathered chicks on day one, and poor body condition in older chickens as well as swollen kidneys. Histopathological examination of CAstV-infected birds showed mild proventriculitis, shortening of intestinal villi, enteritis, focal hepatocellular necrosis, pericarditis, myocarditis, and proliferative response in lung tissue. Kidneys showed interstitial nephritis, urate deposition, and glomerular hypercellularity. CAstV is a chicken pathogen that could be related to decreased performance, and screening of flocks for CAstV might be an essential step for breeders.

Oral Inoculation of Point-of-Lay Hens with the New South Wales Outbreak Strain of Salmonella Enteritidis Phage Type 12 Causes Infection, but Minimal Histopathology.

An outbreak of food poisoning in New South Wales (NSW) Australia in 2018, caused by Salmonella enterica serovar Enteritidis phage type 12 (PT12), was traced to eggs consumed from a NSW layer flock. This was the first report of Salmonella Enteritidis infection in NSW layer flocks, despite ongoing environmental monitoring. Clinical signs and mortalities were minimal in most flocks, although seroconversion and infection were demonstrated in some flocks. An oral dose-response challenge study with Salmonella Enteritidis PT12 was undertaken in commercial point-of-lay hens. Cloacal swabs collected at 3, 7, 10, and 14 days postinoculation and caeca, liver, spleen, ovary, magnum, and isthmus tissues collected at necropsy at either 7 or 14 days were processed for Salmonella isolation (AS 5013.10-2009 from ISO6579:2002). Histopathology was performed on the above tissues, as well as lung, pancreas, kidney, heart, and additional intestinal and reproductive tract tissues. Salmonella Enteritidis was consistently detected in cloacal swabs between 7 and 14 days postchallenge. The Salmonella Enteritidis PT12 isolate successfully colonized the gastrointestinal tract, liver, and spleen of all hens orally challenged with 107, 108, and 109 Salmonella Enteritidis, and less consistently colonized their reproductive tracts. On histopathology, mild lymphoid hyperplasia in the liver and spleen, along with hepatitis, typhlitis, serositis, and salpingitis, was observed at 7 and 14 days postchallenge, with a greater proportion of affected birds in the two higher dose groups. Diarrhea and culture of Salmonella Enteritidis from heart blood were not detected in challenged layers. The NSW isolate of Salmonella Enteritidis PT12 was able to invade and colonize the birds' reproductive tracts as well as a wide range of other tissues, indicating the potential for these naive commercial hens to contaminate their eggs.

Prevalence and Characterization of Salmonella Isolated from Chickens in Anhui, China.

Salmonella is one of the most important zoonotic pathogens that can cause both acute and chronic illnesses in poultry flocks, and can also be transmitted to humans from infected poultry. The purpose of this study was to investigate the prevalence, antimicrobial resistance, and molecular characteristics of Salmonella isolated from diseased and clinically healthy chickens in Anhui, China. In total, 108 Salmonella isolates (5.66%) were successfully recovered from chicken samples (n = 1908), including pathological tissue (57/408, 13.97%) and cloacal swabs (51/1500, 3.40%), and S. Enteritidis (43.52%), S. Typhimurium (23.15%), and S. Pullorum (10.19%) were the three most prevalent isolates. Salmonella isolates showed high rates of resistance to penicillin (61.11%), tetracyclines (47.22% to tetracycline and 45.37% to doxycycline), and sulfonamides (48.89%), and all isolates were susceptible to imipenem and polymyxin B. In total, 43.52% isolates were multidrug-resistant and had complex antimicrobial resistance patterns. The majority of isolates harbored cat1 (77.78%), blaTEM (61.11%), and blaCMY-2 (63.89%) genes, and the antimicrobial resistance genes in the isolates were significantly positively correlated with their corresponding resistance phenotype. Salmonella isolates carry high rates of virulence genes, with some of these reaching 100% (invA, mgtC, and stn). Fifty-seven isolates (52.78%) were biofilm-producing. The 108 isolates were classified into 12 sequence types (STs), whereby ST11 (43.51%) was the most prevalent, followed by ST19 (20.37%) and ST92 (13.89%). In conclusion, Salmonella infection in chicken flocks is still serious in Anhui Province, and not only causes disease in chickens but might also pose a threat to public health security.

Detection and Characterization of Goose Astrovirus Infections in Hatcheries and Commercial Goose Flocks

Goose astrovirus (GoAstV) has frequently been isolated in China since it was first identified as the etiological agent of visceral gout in goslings in 2017. However, the actual prevalence of GoAstV infection and its economic impact on commercial goose production remain poorly characterized. Here, virus detection and serological testing were conducted to determine the extent of GoAstV infection in commercial goose flocks. We detected GoAstV RNA in 2% (6/300) of dead-in-shell embryos and day-old hatched goslings by RT-PCR, indicating vertical transmission under natural conditions. Using a virus neutralization test, GoAstV antibodies were detected in 41.7%–61.1% of serum samples from four commercial goose flocks, indicating that infections were common. To determine the virus types circulating in the commercial flocks, we isolated 15 GoAstVs from goose tissue samples from farms located in five provinces during 2018–2022. Genomic sequence analysis showed that all sequences were corresponded to GoAstV group 2 (GoAstV-2) but were assigned into three capsid subgroups based on sequence variations in the capsid protein. Representative isolates of capsid subgroups were also antigenically evaluated using cross-neutralization tests in LMH cell cultures. The antigenic relatedness values (R) calculated using the Horsfall formula were between 62% and 86%, indicating that no significant antigenic differences exist between the isolates. Our findings indicate that GoAstV-2 viruses are an important cause of fatal gout in goose flocks, as well as hatchery contamination in China.

Impacts of Schmallenberg virus infection in early lambing sheep flocks following the second wave of virus circulation in South West England in 2012/2013: a mixed-methods descriptive study

Impacts of Schmallenberg virus infection in early lambing sheep flocks following the second wave of virus circulation in South West England in 2012/2013: a mixed-methods descriptive study

Molecular characterization and antimicrobial susceptibility profiles of Thai Mycoplasma synoviae isolates

Mycoplasma synoviae (MS) infection is mainly controlled by pathogen-free flocks’ maintenance, medication in infected flocks, and vaccination in high-risk flocks. The effective control strategy requires convenient approach for detecting and differentiating MS strains and reliable drug susceptible evidence for deciding on reasonable antimicrobial usage. This study aimed to characterize the partial vlhA gene of nine Thai MS isolates circulated in chickens in 2020, to verify the PCR-RFLP assay for strain differentiation, and to determine the eight antimicrobial susceptibility profiles using microbroth dilution method. Based on sequence analysis of the partial vlhA gene, Thai MS isolates in 2020 were classified as types E and L with 19 and 35 amino acid lengths, respectively. The developed PCR-RFLP assay could detect and differentiate vaccine and Thai field strains. Most Thai MS isolates in this study were susceptible to tylosin, tylvalosin, tiamulin, doxycycline, oxytetracycline, tilmicosin, and lincomycin-spectinomycin at MIC50 values of 0.0391, 0.0098, 0.0781, 0.1563, 0.1563, 0.625 and 0.625 μg/mL, respectively; and resistance to enrofloxacin at MIC50 value of 10 μg/mL. In conclusion, this study revealed diagnostic assays for differentiating MS strains and the antimicrobial susceptibility profiles of Thai MS, which are necessary to design suitable MS control procedures for poultry flocks.

A Multiplex PCR Assay for Differential Identification of Wild-type and Vaccine Strains of Mycoplasma gallisepticum

Mycoplasma gallisepticum (MG) can cause respiratory disease in chickens and result in serious economic losses in the chicken industry. The use of live vaccines has been a favorable option for the control of MG infection in multi-age commercial layers and broiler breeders. There are three live vaccines, including ts-11, 6/85, and F strain, that have been commonly used in various parts of the world, including South Korea. The definitive diagnosis of the infection, therefore, requires the differentiation of wild-type field strains of MG from the vaccine strains used. Thus, we aimed to develop a novel multiplex PCR assay to discriminate between vaccine strains (ts-11, 6/85, and F strain) and wild-type field strains of MG isolated from infected chickens. We designed four novel primer sets that are each specific to MG species, ts-11, 6/85, and F strain. The multiplex PCR assay using the primer sets differentially identified wild-type and vaccine strains of MG but did not detect other avian bacteria. The detection limit of this assay was 250 fg/μL of genomic DNA of each strain tested. In addition, this assay was applied to 36 MG strains isolated from chickens over the past 20 years in South Korea. As a result, the assay identified 22 wild-type strains and 14 vaccine strains. Consequently, the novel multiplex PCR assay can discriminate between vaccine and wild-type field strains of MG and could be a valuable tool for the diagnosis of MG infection in MG-vaccinated chicken flocks.

Study of Salmonella detection in laying hens using a Bayesian model.

As part of the measures to reduce the prevalence of Salmonella in poultry in the UK, National Control Programmes (NCPs) have been implemented. These involve regular statutory testing of poultry holdings to monitor and estimate the prevalence of Salmonella in the national flock population and to control Salmonella on holdings with positive flocks, especially those serovars most identified with human illness: Salmonella Enteritidis (SE) and S.Typhimurium (ST). It is very important to ensure that the level of testing is appropriate so that it is sufficiently effective to identify positive flocks and to monitor prevalence, but also efficient in the use of resources. The aim of this study was to estimate the sensitivity of both the Operator and Competent Authority (CA) Official sampling used to detect infected flocks, and to also estimate the true proportion of infected holdings of commercial laying flocks in GB each year of the NCP, along with the trend of any changes in prevalence for both SE/ST and non-SE/ST. A Bayesian model was developed to estimate the sensitivity of both Operator and CA Official sampling from the NCP data 2009-2018, and to estimate the true prevalence of infected holdings. The model estimate for the prevalence of infected holdings for the first complete year of the NCP was 3.9% (95% Credible Interval (CI) 2.8-6.2%) for non-SE/ST and 0.8% (95% CI: 0.4%-1.5%) for SE/ST. Prevalence had reduced to 1.6% (non-SE/ST) (95% CI 1.0%-2.5%) and 0.2% (SE/ST) (95% CI 0.1%-0.4%) in 2018. Results indicated a very low sensitivity of Operator sampling (~9%), but a much higher sensitivity of CA Official sampling (~44%). The true prevalence of Salmonella infected holdings in the UK had a mean average reduction of 10.6% (95% CI: 6.3%-15.1%) per annum (non-SE/ST) and 15.9% (95% CI: 6.0%-19.8%) annual reduction for SE/ST. This has shown the effectiveness of the NCP for Salmonella in commercial laying flocks, with reductions in Salmonella overall more or less equal to the target reduction for regulated serovars of 10% per annum. The true prevalence of SE/ST was estimated to be below the final target of less than 2% in every year and was below 0.5% at the end of the 10 year period.

The role of the major viral pathogens in a respiratory disease outbreak of broiler flocks in Eastern Iran.

Infectious bronchitis virus (IBV), Newcastle disease virus (NDV), and avian influenza virus (AIV) H9N2 are major viral pathogens in broiler respiratory disease. Following a respiratory disease outbreak and economic losses in eastern Iran 2020-2021, we investigated the role of major viral pathogens and the implemented vaccination programs. Thirty-six respiratory disease affected broiler flocks in South Khorasan province were sampled, molecularly tested, and coinfections were investigated. The vaccination programs were obtained and the detected IBV were genotyped. IBV, virulent NDV, and AIV H9N2 were detected in twenty-five, seven, and seven flocks, respectively. IBV+AIV, IBV+NDV, and NDV+AIV coinfections were respectively detected in six, five, and one flocks. Most IBV infected flocks (84%) had been immunized with a live IBV-Mass vaccine. All NDV infected flocks and 14.2% of AIV infected flocks had been vaccinated. IBV genotyping showed a high prevalence of variant 2 (83.3%), followed by Mass-type (12.5%), and Q1-type (4.2%). Variant 2 IB viruses were widely distributed in the province and half of them were mostly similar to the ones that had been detected in northern neighboring province, Khorasan Razavi. Single infection with variant 2 IBV was a major cause of the respiratory disease outbreak in which use of the Mass vaccine was probably not effective. The high coverage and multiple doses of vaccination against Newcastle disease possibly had reduced the prevalence of NDV. Considering the regional origin of IBV strains, strong biosecurity measures should be implemented and vaccination programs using appropriate vaccine strains should be used.

Study of the prevalence of Salmonella Arizonae infection in backyard and commercial turkey flocks in Golestan, Mazandaran, Gilan, and Tehran provinces

Arizona infection or avian arizonosis (AA) is an acute or chronic egg-transmitted disease of primarily young turkey poults characterized by septicemia, neurological signs, blindness, and increased mortality, caused by caused by the bacterium Salmonella enterica subsp. Arizonae (S. Arizonae ). This study investigated the infection rate of Salmonella Arizonae in backyard and commercial turkeys of Golestan, Mazandaran, Gilan, and Tehran provinces. Fecal samples taken from industrial and backyard turkeys were transferred to cysteine selenite enrichment medium, incubated at 37° C for 24 hours, and then cultured linearly in selected media of Chromagar, Salmonella-Shigela, XLD, and McConkey agar plates and exposed to 37° C for 24 hours. Suspected Salmonella colonies were cultured in differentiated TSI and urea medium for confirmation and incubated at 37° C for 24 h. In this study, the microbial culture method was used by pre-enrichment, specific, and differential media to determine the level of contamination of backyard and industrial turkey flocks in four provinces of Golestan, Mazandaran, Gilan, and Tehran. All samples were tested for Salmonella infection, but positive samples were not found for Salmonella. Only 22 specimens were infected with Proteus. Our information about the Iranian turkey industry is limited compared to worldwide studies. This may be due to Iran's less widespread use of turkey production. The non-isolation of Salmonella in this study is inconsistent with some of the few studies in the country, which may be due to differences in the type of sampling, geographical location, and materials and methods of work. Due to the growth of the turkey industry in the country, the importance of studying Salmonella and other pathogens is felt more than ever.

EPIDEMIOLOGICAL AND DIAGNOSTIC STATUS OF MYCOPLASMA SYNOVIAE IN PAKISTAN AND INDIA: A REVIEW

Poultry birds are affected with lot of infectious diseases in which Mycoplasma synoviae is one of vital significance. Mycoplasma infection can be diagnosed on several basis including history of disease in chickens, clinical signs of infected chickens, necropsy practices, microscopic lesions, and several diagnostic methods. Once, observing the clinical signs, necropsy practice is considered as the best method to identify the target pathogen as Mycoplasma synoviae, showing the specific type of postmortem lesions. Mycoplasma detection can also be done by several serological and molecular techniques. Early diagnosis of mycoplasma can be done by using serological tests. Status of Mycoplasma was observed time to time in Pakistan and India and presented in this review. Mycoplasma can be controlled by timely vaccination of layer chickens, appropriate and routine screening the breeder flock and culling of infected birds or flocks. Once the chickens are infected with mycoplasma, it remains infected for their entire life, so eradicate the whole flock, to avoid future losses to poultry birds due to this pathogen. This review paper will explain the current status of Mycoplasma synoviae and diagnostic techniques in Pakistan and India.