Tracheal post-vaccinal reaction to different strains of Newcastle disease vírus / Reação traqueal pós-vacinal à diferentes cepas do vírus da doença de Newcastle

The aim of the present study was to evaluate the post-vaccinal reaction to two lentogenic vaccine strains of Newcatle disease virus (NDV) and a recombinant turkey herpesvirus (rHVT) vaccine expressing the fusion glycoprotein of NDV in broiler chickens through histomorphometric and histopathologic analyses of the trachea. The experiment involved 245 chicks housed in randomized blocks with three different enclosures under controlled conditions of temperature, light and ventilation. Each enclosure represented a vaccine strain and was divided into groups according to the administration route. Each block also had its own control group composed of unvaccinated birds. The vaccine strains PHY.LMV.42 (PL42) and La Sota (LS) were selected according to the Intracerebral Pathogenicity Index (ICPI) and the rHVT-NDV Serotype 3 strain (ST3) was selected for representing non-NDV infection. At two, four, seven, 14 and 21 days post vaccination, fragments from the middle third of the trachea were collected and submitted to routine histological processing. For the histomorphometric analysis, the slides were photographed, and the thickness of the tracheal mucosa was measured. Statistical analysis involved two-way ANOVA and Tukey's post-hoc test with a 5% significance level. For the histopathological evaluation, lesions were described as to the degree of intensity and distribution. At four and 14 days post vaccination with the LS strain administered by the ocular route, the means of thickening of the tracheal mucosa (20.85±7.31µm and 26.97±5.50µm, respectively) were significantly higher (p<0.05) than for all other strains, which was related to the severe histopathological lesions found in this group, characterized by hyperemia, hyperplasia of the mucous glands, moderate deciliation and multifocal lymphohistiocytic inflammatory infiltrate. At 21 days, broiler chickens vaccinated with the ST3 strain showed more discrete lesions and less thickening of the tracheal mucosa (23.23±7.62µm; p<0.05) in comparison with other studied strains. The lesions found in this group were only hemorrhage, deciliation and mild focal lymphocytic inflammatory infiltrate. The results of the histomorphometry and histopathology of the trachea indicated that vaccination with rHVT-NDV Serotype 3 strain induced lower degree post-vaccine tracheal lesions compared to other vaccine strains analyzed in this study.

Objetivou-se avaliar a reação pós-vacinal de duas estirpes lentogênicas do vírus da doença de Newcastle (VDN) e uma vacina recombinante de herpesvirus de perus (rHVT) que expressa a glicoproteína de fusão de VDN em frangos de corte por meio da histomorfometria e histopatologia da traqueia. Foram utilizados 245 pintos alojados em blocos ao acaso, sendo três galpões distintos em condições controladas de temperatura, luz e ventilação. Cada galpão representou uma cepa vacinal, onde foram divididos por grupos de acordo com a via de administração. Todos os blocos possuíam um grupo controle composto por aves não vacinadas. As cepas vacinais PHY.LMV.42 (PL42) e La Sota (LS) utilizadas foram selecionadas de acordo com o Índice de Patogenicidade Intracerebral (IPIC) e a cepa Sorotipo 3 (ST3), da vacina rHVT-VDN foi selecionada por não representar infecção do VDN. Aos dois, quarto, sete, 14 e 21 dias pós-vacinação, fragmentos do terço médio da traqueia foram coletados e posteriormente processados conforme rotina histológica. Para análise histomorfométrica da mucosa traqueal, as lâminas foram fotografadas e realizadas as mensurações da espessura da mucosa traqueal sendo aplicado teste de análise de variância a dois critérios (ANOVA) e utilizando o post-hoc de Tukey com nível de significância de 5%. Para a avaliação histopatológica foram observadas a presença de lesões microscópicas e estas foram descritas quanto ao grau de intensidade e distribuição. Aos quatro e quatorze dias pós-vacinação com a cepa LS administrada por via ocular, as médias do espessamento da mucosa traqueal (20,85±7,31µm e 26,97±5,50µm, respectivamente) foram significativamente maiores (p<0,05) quando comparada a todas as demais cepas utilizadas, isto se deve às severas lesões histopatológicas encontrados neste grupo, caracterizadas por hiperemia, hiperplasia das glândulas mucosas, deciliação moderada e infiltrado inflamatório linfohistiocitário multifocal moderado. Já aos 21 dias as aves vacinadas com a cepa ST3 apresentaram lesões mais discretas e menor espessamento da mucosa da traqueia (23,23±7,62µm; p<0,05) em comparação às demais cepas estudadas. As lesões encontradas neste grupo foram apenas hemorragia, deciliação e infiltrado inflamatório linfocitário focal discreto. Os resultados da histomorfometria e da histopatologia da traqueia indicou que a vacinação com a rHVT-NDV, cepa Sorotipo 3 induziu menor grau de lesões pós-vacinais na traqueia comparada a outras cepas vacinais analisadas nesse estudo.

Effect of Dietary Inclusion of Sodium Bicarbonate on Digestibility of Nutrients and Immune Response in Caged Layers During the Summer

The aim of this project was to investigate the effect of dietary inclusion of sodium bicarbonate (NaHCO3) on nutrient digestibility and immune response of caged layers during summer when the temperature exceeds 40 C. For immune response trial, White Leghorn layers (n=160; 24 weeks old) were purchased from a poultry farm and were divided into five treatment/diets groups (4 replicate/treatment). Diet A, was without NaHCO3 and served as control whereas, diets B, C, D, and E contained 0.5, 1.0, 1.5 and 2.0% NaHCO3, respectively. All these birds were vaccinated against Newcastle disease (ND) virus at the start of the experiment and thereafter with one-month intervals. Blood samples were collected from two birds/replicate at 10 days post vaccination each time to check antibody titer against ND virus. For digestibility trial, fecal samples were collected (6 layers/treatment group) at the start of the 37th week of age for two days, at 3 hours interval. Results revealed that immune response against ND virus 10 days post vaccination after 1st, 2nd and 3rd month was significantly (p 0.05) higher in layer birds fed diets containing NaHCO3. Digestibility of dry matter (DM), crude protein (CP), crude fiber (CF), ether extract (EE) and absorption of minerals were also found to be significantly (p 0.05) higher in groups treated with NaHCO3 and the birds fed diet containing 1% NaHCO3 showed the best results. In general, results revealed that 1% supplementation of NaHCO3 in layers diet have a beneficial impact in terms of immunity and diet digestibility.(AU)

Effect of Dietary Inclusion of Sodium Bicarbonate on Digestibility of Nutrients and Immune Response in Caged Layers During the Summer

The aim of this project was to investigate the effect of dietary inclusion of sodium bicarbonate (NaHCO3) on nutrient digestibility and immune response of caged layers during summer when the temperature exceeds 40 C. For immune response trial, White Leghorn layers (n=160; 24 weeks old) were purchased from a poultry farm and were divided into five treatment/diets groups (4 replicate/treatment). Diet A, was without NaHCO3 and served as control whereas, diets B, C, D, and E contained 0.5, 1.0, 1.5 and 2.0% NaHCO3, respectively. All these birds were vaccinated against Newcastle disease (ND) virus at the start of the experiment and thereafter with one-month intervals. Blood samples were collected from two birds/replicate at 10 days post vaccination each time to check antibody titer against ND virus. For digestibility trial, fecal samples were collected (6 layers/treatment group) at the start of the 37th week of age for two days, at 3 hours interval. Results revealed that immune response against ND virus 10 days post vaccination after 1st, 2nd and 3rd month was significantly (p 0.05) higher in layer birds fed diets containing NaHCO3. Digestibility of dry matter (DM), crude protein (CP), crude fiber (CF), ether extract (EE) and absorption of minerals were also found to be significantly (p 0.05) higher in groups treated with NaHCO3 and the birds fed diet containing 1% NaHCO3 showed the best results. In general, results revealed that 1% supplementation of NaHCO3 in layers diet have a beneficial impact in terms of immunity and diet digestibility.

Phylogenetic and pathotypic characterization of a Newcastle disease virus strain isolated from ducks and pigeons in Hubei, China

Newcastle disease is a highly contagious disease responsible for major outbreaks and considerable economic losses in the poultry industry in China. There is still little information available regarding gene characterization of the NDV, especially in ducks and pigeons. Therefore, the aim of this study was to investigate NDV isolated from ducks and pigeons in Hubei, China. In this study, three NDVs from ducks and pigeons were isolated between 2013 and 2015.The fusion protein (F) gene of the NDV isolates was sequenced and phylogenetically analyzed. The clinical signs and gross histopathological lesions were examined. Phylogenetic analysis of these strains indicated that all the sequences are classified as genotype II. The isolates shared a 112 G-R-Q-G-R-L 117motif at the F protein cleavage site, indicating that these three isolates strains are lentogenic. Necropsy and histopathology showed the typical pathological changes. It was concluded that commercial ducks and pigeons in Hubei province carry lentogenic NDV strains with regular genetic divergence, indicating that these species may act as the main reservoirs of NDV in poultry. Therefore, strategies and surveillance should be undertaken to reduce the risk of ND outbreaks.(AU)

Phylogenetic and pathotypic characterization of a Newcastle disease virus strain isolated from ducks and pigeons in Hubei, China

Newcastle disease is a highly contagious disease responsible for major outbreaks and considerable economic losses in the poultry industry in China. There is still little information available regarding gene characterization of the NDV, especially in ducks and pigeons. Therefore, the aim of this study was to investigate NDV isolated from ducks and pigeons in Hubei, China. In this study, three NDVs from ducks and pigeons were isolated between 2013 and 2015.The fusion protein (F) gene of the NDV isolates was sequenced and phylogenetically analyzed. The clinical signs and gross histopathological lesions were examined. Phylogenetic analysis of these strains indicated that all the sequences are classified as genotype II. The isolates shared a 112 G-R-Q-G-R-L 117motif at the F protein cleavage site, indicating that these three isolates strains are lentogenic. Necropsy and histopathology showed the typical pathological changes. It was concluded that commercial ducks and pigeons in Hubei province carry lentogenic NDV strains with regular genetic divergence, indicating that these species may act as the main reservoirs of NDV in poultry. Therefore, strategies and surveillance should be undertaken to reduce the risk of ND outbreaks.

Phylogenetic and pathotypic characterization of newcastle disease virus in Tibetan chickens, China

Chickens are considered to be potential reservoirs of Newcastle disease virus (NDV). In this study, six Newcastle disease virus strains were isolated and characterized in Tibetan chickens. The HN gene was sequenced, and phylogenetic relationship to reference strains was studied. The phylogenetic analysis demonstrated that these six isolated strains were closely related to NDV isolates of the reference strains GQ245823, KT002186, KU527561, KJ563939, AY225110, EU305607, KM056357, Y18898, GQ245832, AF077761 and lasota strain. Among them, EU305607, KJ563939 and KM056357 were isolated from India, while lasota strain came from attenuated vaccine widely used in China. Then, mean death time (MDT) and intracerebral pathogenicity index (ICPI) were used to estimate the pathogenicity of the isolates. Pathogenicity experiment showed HNH1 and HN17 to be virulent. Our results indicated that genetically diverse viruses circulate in Tibetan chickens, and based upon the phlogeographic analysis, we estimated the origin of ancestral viruses of the isolates and its sister strains located in India and China (lasota strain). It indicates the importance of continuous surveillance to enhance current understanding of the genetic evolution of the NDV strains.(AU)

Evaluation of the Viral Interference between Lentogenic Newcastle Disease Virus (Lasota) and Avian Influenza Virus (H9N2) using Real-Time Reverse Transcription Polymerase Chain Reaction in SPF Chicken

ABSTRACT Lentogenic Newcastle disease virus (lNDV) such as Lasota strain and low pathogenicity avian influenza such as H9N2 virus are two of the most economically important viruses affecting poultry worldwide, and little attention in recent years has been paid to simultaneous infections in chickens with these two viruses for the reason that co-infection do occur but are not easily detected. In the present study, chickens were inoculated with lNDV (Lasota) and LPAIV (A/chicken/Tehran/ZMT-173/99(H9N2)) simultaneously or sequentially three days apart. Oropharyngeal and cloacal swabs were collected from chickens from 1 to 14 days after inoculation. RRT-PCR for AIV and NDV detection was performed. The rate of viral shedding was measured within 14 days. No clinical symptoms were observed during the experiment however the pattern of virus shed was different with co-infection, thus comparing the results obtained from viral shedding showed that AIV is a much stronger agent than NDV in the occurrence of viral interference. This is due to the fact that in simultaneous inoculation, AIV replication delayed and reduced NDV replication, while replication of Lasota in simultaneous or pre-inoculated inoculation could not significantly disrupt H9N2 virus replication. These findings indicate that the infection with one virus can interfere with the replication of another, modifying the pathogenesis of the viruses. So, infection of the host with both viral agents simultaneously causes higher shedding of LPAIV than lNDV in OP and CL areas. In conclusion, co-infection with LPAVI in chickens did not impact clinical signs but affected the replication dynamics of these viruses.

Evaluation of the Viral Interference between Lentogenic Newcastle Disease Virus (Lasota) and Avian Influenza Virus (H9N2) using Real-Time Reverse Transcription Polymerase Chain Reaction in SPF Chicken

Lentogenic Newcastle disease virus (lNDV) such as Lasota strain and low pathogenicity avian influenza such as H9N2 virus are two of the most economically important viruses affecting poultry worldwide, and little attention in recent years has been paid to simultaneous infections in chickens with these two viruses for the reason that co-infection do occur but are not easily detected. In the present study, chickens were inoculated with lNDV (Lasota) and LPAIV (A/chicken/Tehran/ZMT-173/99(H9N2)) simultaneously or sequentially three days apart. Oropharyngeal and cloacal swabs were collected from chickens from 1 to 14 days after inoculation. RRT-PCR for AIV and NDV detection was performed. The rate of viral shedding was measured within 14 days. No clinical symptoms were observed during the experiment however the pattern of virus shed was different with co-infection, thus comparing the results obtained from viral shedding showed that AIV is a much stronger agent than NDV in the occurrence of viral interference. This is due to the fact that in simultaneous inoculation, AIV replication delayed and reduced NDV replication, while replication of Lasota in simultaneous or pre-inoculated inoculation could not significantly disrupt H9N2 virus replication. These findings indicate that the infection with one virus can interfere with the replication of another, modifying the pathogenesis of the viruses. So, infection of the host with both viral agents simultaneously causes higher shedding of LPAIV than lNDV in OP and CL areas. In conclusion, co-infection with LPAVI in chickens did not impact clinical signs but affected the replication dynamics of these viruses.(AU)

Phylogenetic and pathotypic characterization of newcastle disease virus in Tibetan chickens, China

Chickens are considered to be potential reservoirs of Newcastle disease virus (NDV). In this study, six Newcastle disease virus strains were isolated and characterized in Tibetan chickens. The HN gene was sequenced, and phylogenetic relationship to reference strains was studied. The phylogenetic analysis demonstrated that these six isolated strains were closely related to NDV isolates of the reference strains GQ245823, KT002186, KU527561, KJ563939, AY225110, EU305607, KM056357, Y18898, GQ245832, AF077761 and lasota strain. Among them, EU305607, KJ563939 and KM056357 were isolated from India, while lasota strain came from attenuated vaccine widely used in China. Then, mean death time (MDT) and intracerebral pathogenicity index (ICPI) were used to estimate the pathogenicity of the isolates. Pathogenicity experiment showed HNH1 and HN17 to be virulent. Our results indicated that genetically diverse viruses circulate in Tibetan chickens, and based upon the phlogeographic analysis, we estimated the origin of ancestral viruses of the isolates and its sister strains located in India and China (lasota strain). It indicates the importance of continuous surveillance to enhance current understanding of the genetic evolution of the NDV strains.(AU)

Phylogenetic and pathotypic characterization of newcastle disease virus in Tibetan chickens, China

ABSTRACT: Chickens are considered to be potential reservoirs of Newcastle disease virus (NDV). In this study, six Newcastle disease virus strains were isolated and characterized in Tibetan chickens. The HN gene was sequenced, and phylogenetic relationship to reference strains was studied. The phylogenetic analysis demonstrated that these six isolated strains were closely related to NDV isolates of the reference strains GQ245823, KT002186, KU527561, KJ563939, AY225110, EU305607, KM056357, Y18898, GQ245832, AF077761 and lasota strain. Among them, EU305607, KJ563939 and KM056357 were isolated from India, while lasota strain came from attenuated vaccine widely used in China. Then, mean death time (MDT) and intracerebral pathogenicity index (ICPI) were used to estimate the pathogenicity of the isolates. Pathogenicity experiment showed HNH1 and HN17 to be virulent. Our results indicated that genetically diverse viruses circulate in Tibetan chickens, and based upon the phlogeographic analysis, we estimated the origin of ancestral viruses of the isolates and its sister strains located in India and China (lasota strain). It indicates the importance of continuous surveillance to enhance current understanding of the genetic evolution of the NDV strains.

Evaluation of the Viral Interference between Lentogenic Newcastle Disease Virus (Lasota) and Avian Influenza Virus (H9N2) using Real-Time Reverse Transcription Polymerase Chain Reaction in SPF Chicken

Lentogenic Newcastle disease virus (lNDV) such as Lasota strain and low pathogenicity avian influenza such as H9N2 virus are two of the most economically important viruses affecting poultry worldwide, and little attention in recent years has been paid to simultaneous infections in chickens with these two viruses for the reason that co-infection do occur but are not easily detected. In the present study, chickens were inoculated with lNDV (Lasota) and LPAIV (A/chicken/Tehran/ZMT-173/99(H9N2)) simultaneously or sequentially three days apart. Oropharyngeal and cloacal swabs were collected from chickens from 1 to 14 days after inoculation. RRT-PCR for AIV and NDV detection was performed. The rate of viral shedding was measured within 14 days. No clinical symptoms were observed during the experiment however the pattern of virus shed was different with co-infection, thus comparing the results obtained from viral shedding showed that AIV is a much stronger agent than NDV in the occurrence of viral interference. This is due to the fact that in simultaneous inoculation, AIV replication delayed and reduced NDV replication, while replication of Lasota in simultaneous or pre-inoculated inoculation could not significantly disrupt H9N2 virus replication. These findings indicate that the infection with one virus can interfere with the replication of another, modifying the pathogenesis of the viruses. So, infection of the host with both viral agents simultaneously causes higher shedding of LPAIV than lNDV in OP and CL areas. In conclusion, co-infection with LPAVI in chickens did not impact clinical signs but affected the replication dynamics of these viruses.

Pathological and molecular findings of avian avulavirus type 1 outbreak in pigeons (Columba livia) of southern Brazil / Achados patológicos e moleculares da infecção por avulavirus aviário tipo 1 em pombos (Columba livia) do sul do Brasil

The Newcastle disease, caused by avian avulavirus type 1 strains (APMV-1) is an important avian disease involved into high rates of mortality and economic losses. Several outbreaks have been reported over the last 30 years in Columbiformes in different parts of the world, caused by a adapted variant strain of AAvV-1, called pigeon paramyxovirus type 1 (PPMV-1). A high mortality associated with an outbreak was analyzed in free-living pigeons (Columba livia) in a public square in Porto Alegre in Southern Brazil. A total of 24 pigeons moribund or freshly dead, within five weeks interval were submitted to necropsy, histopathological, immunohistochemical (anti-Newcastle), and RT-PCR followed by sequencing of the amplification products analysis. They presented neurological signs, non-suppurative encephalitis and encephalomyelitis, and mononuclear inflammatory infiltrate in different organs. Immunohistochemical analysis in nine pigeons tissue showed that anti-Newcastle was expressed in brain, kidney, liver and pancreas. The RT-PCR test for the M protein of Newcastle disease virus was positive in six pigeons. The differential diagnosis of Influenza, West Nile, Mycoplasma gallisepticum and Mycoplasma synoviae in all pigeons presented negative results. The sequence of amino acids in the cleavage site region of the F protein was 112RRQKRF117 classifying the strain as virulent. The phylogenetic analysis classified this virus strain into Class II and VI genotype.(AU)

A doença de Newcastle, causada por cepas de avulavirus aviário tipo 1 (AAvV-1), é uma doença de aves importante por causar altos índices de mortalidade e perdas econômicas. Vários surtos têm sido relatados ao longo de 30 anos em aves da ordem Columbiformes, em diferentes partes do mundo, causados por uma cepa variante específica de AAvV-1, denominada Pigeon paramyxovirus tipo 1 (PPMV-1). Foi analisado um surto de mortalidade em pombos domésticos (Columba livia), provenientes de uma praça pública em Porto Alegre, no Sul do Brasil. Vinte e quatro aves moribundas ou mortas foram submetidas, no intervalo de cinco semanas, ao exame de necropsia, exame histopatológico, imuno-histoquímico anti-Newcastle, RT-PCR e sequenciamento. Apresentaram sinais neurológicos, encefalite e encefalomielite não supurativas, além de infiltrado inflamatório mononuclear em diversos órgãos. Nove aves demonstraram exame imuno-histoquímico positivo em órgãos como cérebro, rim, fígado e pâncreas. Seis aves foram positivas no exame de RT-PCR para a proteína M do vírus da Doença de Newcastle. Nos exames de diagnósticos diferenciais de Influenza, West Nile, Mycoplasma gallisepticum e Mycoplasma synoviae, todas as aves testadas foram negativas. A sequência dos aminoácidos na região do sítio de clivagem da proteína foi 112RRQKRF117, classificando a cepa como virulenta. De acordo com a análise filogenética o vírus identificado foi classificado como pertencente à classe II e ao genótipo VI.(AU)

Pathological and molecular findings of avian avulavirus type 1 outbreak in pigeons (Columba livia) of southern Brazil / Achados patológicos e moleculares da infecção por avulavirus aviário tipo 1 em pombos (Columba livia) do sul do Brasil

The Newcastle disease, caused by avian avulavirus type 1 strains (APMV-1) is an important avian disease involved into high rates of mortality and economic losses. Several outbreaks have been reported over the last 30 years in Columbiformes in different parts of the world, caused by a adapted variant strain of AAvV-1, called pigeon paramyxovirus type 1 (PPMV-1). A high mortality associated with an outbreak was analyzed in free-living pigeons (Columba livia) in a public square in Porto Alegre in Southern Brazil. A total of 24 pigeons moribund or freshly dead, within five weeks interval were submitted to necropsy, histopathological, immunohistochemical (anti-Newcastle), and RT-PCR followed by sequencing of the amplification products analysis. They presented neurological signs, non-suppurative encephalitis and encephalomyelitis, and mononuclear inflammatory infiltrate in different organs. Immunohistochemical analysis in nine pigeons tissue showed that anti-Newcastle was expressed in brain, kidney, liver and pancreas. The RT-PCR test for the M protein of Newcastle disease virus was positive in six pigeons. The differential diagnosis of Influenza, West Nile, Mycoplasma gallisepticum and Mycoplasma synoviae in all pigeons presented negative results. The sequence of amino acids in the cleavage site region of the F protein was 112RRQKRF117 classifying the strain as virulent. The phylogenetic analysis classified this virus strain into Class II and VI genotype.(AU)

A doença de Newcastle, causada por cepas de avulavirus aviário tipo 1 (AAvV-1), é uma doença de aves importante por causar altos índices de mortalidade e perdas econômicas. Vários surtos têm sido relatados ao longo de 30 anos em aves da ordem Columbiformes, em diferentes partes do mundo, causados por uma cepa variante específica de AAvV-1, denominada Pigeon paramyxovirus tipo 1 (PPMV-1). Foi analisado um surto de mortalidade em pombos domésticos (Columba livia), provenientes de uma praça pública em Porto Alegre, no Sul do Brasil. Vinte e quatro aves moribundas ou mortas foram submetidas, no intervalo de cinco semanas, ao exame de necropsia, exame histopatológico, imuno-histoquímico anti-Newcastle, RT-PCR e sequenciamento. Apresentaram sinais neurológicos, encefalite e encefalomielite não supurativas, além de infiltrado inflamatório mononuclear em diversos órgãos. Nove aves demonstraram exame imuno-histoquímico positivo em órgãos como cérebro, rim, fígado e pâncreas. Seis aves foram positivas no exame de RT-PCR para a proteína M do vírus da Doença de Newcastle. Nos exames de diagnósticos diferenciais de Influenza, West Nile, Mycoplasma gallisepticum e Mycoplasma synoviae, todas as aves testadas foram negativas. A sequência dos aminoácidos na região do sítio de clivagem da proteína foi 112RRQKRF117, classificando a cepa como virulenta. De acordo com a análise filogenética o vírus identificado foi classificado como pertencente à classe II e ao genótipo VI.(AU)

Survey of pathogens in threatened wild red-tailed Amazon parrot (Amazona brasiliensis) nestlings in Rasa Island, Brazil

ABSTRACT The red-tailed Amazon parrot (Amazona brasiliensis) is a threatened species of psittacine bird that inhabit coastal regions of Brazil. In view of the threat of this species, the aim of this study was to perform a health evaluation in wild nestlings in Rasa Island, determining the prevalence of enterobacteria and infectious agents according to type of nest. Blood samples were collected from 64 birds and evaluated for antibodies of Chlamydia psittaci by commercial dot-blot ELISA. Cloacal and oropharyngeal swabs samples were collected from 23 birds from artificial wooden nests, 15 birds from PVC nests and 2 birds from natural nests for microbiological analysis. Swab samples were collected from 58 parrots for C. psittaci detection by PCR and from 50 nestlings for Avian Influenza, Newcastle Disease and West Nile viruses detection analysis by real-time RT-PCR. Ten bacterial genera and 17 species were identified, and the most prevalent were Escherichia coli and Klebsiella oxytoca. There was no influence of the type of nest in the nestlings microbiota. All samples tested by ELISA and PCR were negative. There is currently insufficient information available about the health of A. brasiliensis and data of this study provide a reference point for future evaluations and aid in conservation plans.(AU)

Serological Detection of Newcastle Disease Virus Antibodies in Local Chickens and Guinea Fowls in the Area of Kumasi, Ghana

Newcastle Disease (ND) has been identified as a major constraint to local poultry production with its impact being felt more in rural poultry production which forms about 80% of Ghana poultry population. However documented evidence on ND virus activity in rural poultry in Ghana is still lacking. Hence, this study was conducted to evaluate the level of circulating antibodies against ND using the Haemagglutination Inhibition (HI) technique. Sera collected from unvaccinated 292 chickens and 153 guinea fowls randomly selected from households and a live bird market in Kumasi and its environs were evaluated for Newcastle disease virus antibodies. Results showed 81.8 % (239/292) of local chickens and 24.2 % (37/153) of guinea fowls tested positive for ND antibodies. Comparison was made between the seroprevalence of ND antibodies in household and live bird market as well as between sexes. Significantly higher prevalence rate (p 0.05) was observed with chickens sampled from households compared to those from the live bird market. Higher ranges of titers were also observed in chickens from households than those from live bird markets. The presence of ND antibodies in these unvaccinated local chickens and guinea fowls indicated the presence of the virus amongst the rural poultry population, hence aneed for improvement in vaccine campaignand delivery against ND for rural poultry especially with the use of thermostable and improved oral or feed-based vaccine delivery systems.

Comparative evaluation of the protective efficacy of different vaccination programs against a virulent field strain of the Newcastle disease virus in broilers

Despite the intensive vaccination programs used for controlling Newcastle disease (ND) in the Iranian poultry industry, outbreaks of ND have been reported in poultry farms. This study was conducted to evaluate the effectiveness of vaccines for the protection against ND infection and virus-shedding period of velogenic Newcastle disease virus (vNDV) field strain after different immunization schemes. Eight groups of commercial broiler chickens were used. Six groups were vaccinated with different vaccination programs using commercial live and inactivated ND vaccines. All groups, except for group 8, were challenged with a virulent field isolate (104EID50/bird) at 28 days of age. Clinical signs, mortality rate and gross lesions were investigated. Antibody titers were assayed by hemagglutination inhibition test and fecal virus shedding was determined for 14 days post challenge (dpc) with 3-day intervals by the RT-PCR method. All unvaccinated-challenged control birds died. Vaccination with these ND vaccines protected chickens from clinical disease. The mortality rate in the vaccinated groups was significantly lower than in the positive control group. However, vaccinated chickens shed the challenge virus in fecal samples. Although the different vaccination regimens displayed close degrees of protection against the disease, the best protection was observed in broilers primed with the live B1 vaccine via eye drop simultaneously with inactivated vaccine at 8 days of age and boosted with B1 or LaSota via drinking water on day 18. In conclusion, the currently used vaccines with different vaccination schemes can protect chickens against the disease in areas where ND is endemic, while the spread of the field virus to other flocks cannot be prevented.

Screening of feral pigeons (columba livia) for pathogens of veterinary and medical importance

Pathogens of veterinary and medical importance were investigated in 240 feral pigeons (Columba livia) captured in warehouses in São Paulo State, Brazil for one year. Rapid serum agglutination test (RST) was performed for the detection of antibodies against Mycoplasma synoviae, Mycoplasma gallisepticum and Salmonella Pullorum/Gallinarum. Positive samples were submitted to hemagglutination inhibition (HI) and tube seroagglutination tests, respectively. Molecular techniques (RT-PCR and PCR) were performed for Newcastle Diseases Virus (NDV) and Chlamydia psittaci diagnosis. Additionally, HI test was applied to detect antibodies against NDV. Serological results by RST were 3.3% positive for M. synoviae, 2.5% for M. gallisepticum, and 0.4% for S. Pullorum/Gallinarum, all negative on the confirmatory tests performed. NDV RNA or antibodies were not detected. C. psittaci DNA was detected in 13% of the samples. Further research on pigeon health status should be conducted because this species is highly adaptable and their numbers are rapidly rising around the world, posing risks for animals and human beings.

Comparative evaluation of the protective efficacy of different vaccination programs against a virulent field strain of the Newcastle disease virus in broilers

Despite the intensive vaccination programs used for controlling Newcastle disease (ND) in the Iranian poultry industry, outbreaks of ND have been reported in poultry farms. This study was conducted to evaluate the effectiveness of vaccines for the protection against ND infection and virus-shedding period of velogenic Newcastle disease virus (vNDV) field strain after different immunization schemes. Eight groups of commercial broiler chickens were used. Six groups were vaccinated with different vaccination programs using commercial live and inactivated ND vaccines. All groups, except for group 8, were challenged with a virulent field isolate (104EID50/bird) at 28 days of age. Clinical signs, mortality rate and gross lesions were investigated. Antibody titers were assayed by hemagglutination inhibition test and fecal virus shedding was determined for 14 days post challenge (dpc) with 3-day intervals by the RT-PCR method. All unvaccinated-challenged control birds died. Vaccination with these ND vaccines protected chickens from clinical disease. The mortality rate in the vaccinated groups was significantly lower than in the positive control group. However, vaccinated chickens shed the challenge virus in fecal samples. Although the different vaccination regimens displayed close degrees of protection against the disease, the best protection was observed in broilers primed with the live B1 vaccine via eye drop simultaneously with inactivated vaccine at 8 days of age and boosted with B1 or LaSota via drinking water on day 18. In conclusion, the currently used vaccines with different vaccination schemes can protect chickens against the disease in areas where ND is endemic, while the spread of the field virus to other flocks cannot be prevented.(AU)

Screening of feral pigeons (columba livia) for pathogens of veterinary and medical importance

Pathogens of veterinary and medical importance were investigated in 240 feral pigeons (Columba livia) captured in warehouses in São Paulo State, Brazil for one year. Rapid serum agglutination test (RST) was performed for the detection of antibodies against Mycoplasma synoviae, Mycoplasma gallisepticum and Salmonella Pullorum/Gallinarum. Positive samples were submitted to hemagglutination inhibition (HI) and tube seroagglutination tests, respectively. Molecular techniques (RT-PCR and PCR) were performed for Newcastle Diseases Virus (NDV) and Chlamydia psittaci diagnosis. Additionally, HI test was applied to detect antibodies against NDV. Serological results by RST were 3.3% positive for M. synoviae, 2.5% for M. gallisepticum, and 0.4% for S. Pullorum/Gallinarum, all negative on the confirmatory tests performed. NDV RNA or antibodies were not detected. C. psittaci DNA was detected in 13% of the samples. Further research on pigeon health status should be conducted because this species is highly adaptable and their numbers are rapidly rising around the world, posing risks for animals and human beings.(AU)

Serological Detection of Newcastle Disease Virus Antibodies in Local Chickens and Guinea Fowls in the Area of Kumasi, Ghana

Newcastle Disease (ND) has been identified as a major constraint to local poultry production with its impact being felt more in rural poultry production which forms about 80% of Ghana poultry population. However documented evidence on ND virus activity in rural poultry in Ghana is still lacking. Hence, this study was conducted to evaluate the level of circulating antibodies against ND using the Haemagglutination Inhibition (HI) technique. Sera collected from unvaccinated 292 chickens and 153 guinea fowls randomly selected from households and a live bird market in Kumasi and its environs were evaluated for Newcastle disease virus antibodies. Results showed 81.8 % (239/292) of local chickens and 24.2 % (37/153) of guinea fowls tested positive for ND antibodies. Comparison was made between the seroprevalence of ND antibodies in household and live bird market as well as between sexes. Significantly higher prevalence rate (p 0.05) was observed with chickens sampled from households compared to those from the live bird market. Higher ranges of titers were also observed in chickens from households than those from live bird markets. The presence of ND antibodies in these unvaccinated local chickens and guinea fowls indicated the presence of the virus amongst the rural poultry population, hence aneed for improvement in vaccine campaignand delivery against ND for rural poultry especially with the use of thermostable and improved oral or feed-based vaccine delivery systems.(AU)