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1.
Comp Immunol Microbiol Infect Dis ; 68: 101378, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31812120

RESUMO

The objective of this study was to evaluate the efficacy of Herba Cox®, a commercial herbal compound containing extracts from Bombax malabaricum, Aegle marmelos, Anethum foeniculum, Resina salvia, Ferula asafoetida and Papaver somniferum, for the treatment of rabbit hepatic coccidiosis. Thirty rabbits were allocated into three groups (10 × 3), the G1 group served as a negative control group, G2 group (positive control group) was infected with 5 × 104 sporulated E. stiedaeoocysts and served as infected-untreated group, and G3 group was infected with 5 × 104 sporulated E. stiedaeoocysts and treated with Herba Cox®, 1 ml/liter of drinking water, starting 7 days before infection and continuing for 4 weeks post-infection. When compared to the infected group (G2), body weight and weight gain were significantly (P ≤ 0.05) increased, the feed conversion rate was improved and no mortality was detected in infected treated group (G3) and similar to negative control group (G1). In addition, faecal oocyst output and liver enzymes were significantly decreased. Malondialdehyde, nitric oxide, and glutathione concentrations observed in G3 were similar to those in G1. In infected-untreated rabbits (G2), the haemoglobin, lymphocytes, and CD4+/ CD8+ ratio were significantly decreased, while the total leukocyte count, percentage of heterophils, and heterophil/lymphocyte ratio were increased. Significantly more severe histopathological hepatic lesions were observed in G2 when compared to G1 and G3. In conclusion, the obtained results showed that Herba Cox® should be considered a safe and novel effective compound for the treatment of E. stiedae infection in rabbits.

2.
Artigo em Inglês | MEDLINE | ID: mdl-31712184

RESUMO

This study was performed to evaluate the effects of omega-3 supplementation on growth performance, clinical signs, post-mortem lesions, haemagglutination inhibition (HI) antibody titres, gene expression and histopathology in quails (Coturnix coturnix japonica) infected with Newcastle disease virus (NDV) and avian influenza virus (AIV) H9N2. One hundred, 40-day-old male quails were divided into 5 groups: G1, fed a control basal diet; G2A, infected with NDV; G2B, infected with H9N2; G3A, infected with NDV and given omega-3, and G3B, infected with H9N2 and given omega-3. The dietary omega-3 supplementation was continued for 4 weeks: two weeks before infection and two weeks after intranasal infection with virulent NDV and AIV H9N2. Our results revealed significant differences (P < 0.05) in growth performance, HI antibody titres, clinical signs, post-mortem lesions, mortality, viral shedding rates, immunological parameters, and histopathological lesions between the treated (G3A and G3B) and untreated (G2A and G2B) groups. In conclusion, dietary omega-3 supplementation for 4 weeks can improve growth performance and alleviate the deleterious immunological and pathological effects of NDV and AIV H9N2 infection in quails.

5.
Vet Microbiol ; 238: 108429, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31648721

RESUMO

Viral haemorrhagic disease (VHD) and colibacillosis are common diseases in rabbits that cause economic losses worldwide. The effect of colibacillosis on the immune response of vaccinated rabbits against rabbit haemorrhagic disease virus (RHDV) was studied. Four groups (G1-G4) were included. G1 was the negative control group; G2 was the RHDV vaccine group; G3 was the E. coli-infected group; and G4 was the E. coli-infected + RHDV vaccine group. The E. coli infection and RHDV vaccination were simultaneously performed, with another previous infection, 3 days before vaccination. At 28 days post-vaccination (PV), the rabbits (G2-G4) were challenged intramuscularly with 0.5 ml of RHDV at a dose of 103 50% median lethal dose (LD50)/rabbit. The rabbits were observed for clinical signs, body weight gain and mortality rates. Tissue, blood, serum, and faecal samples and rectal swabs were collected at 3, 5, 7, 14, 21 and 28 days PV. Significant clinical signs and mortality and a decrease in BW were observed in the infected + RHDV vaccine group. On the 3rd day post-infection (PI), compared with all the other groups, the vaccinated group (G2) had significantly upregulated hepatic tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels; however, the infected + RHDV vaccine group had significantly higher intestinal levels of TNF-α and IL-6 than the other groups. Furthermore, E. coli infection in vaccinated rabbits led to immunosuppression, as shown by significant decreases (P < 0.05) in heterophil phagocytic activity, the CD4+/CD8+ ratio, and HI antibody responses to RHDV and a significant increase in the heterophil to lymphocyte (H/L) ratio. In conclusion, colibacillosis leads to immunosuppression involving a shift in the equilibrium of cytokines and reduced weight gain and mortality in vaccinated rabbits and could be a contributing factor in RHDV vaccination failure in rabbit farming.


Assuntos
Infecções por Caliciviridae/veterinária , Infecções por Escherichia coli/veterinária , Coelhos/imunologia , Vacinação/veterinária , Vacinas Virais/imunologia , Animais , Infecções por Caliciviridae/imunologia , Infecções por Caliciviridae/mortalidade , Citocinas/genética , Infecções por Escherichia coli/imunologia , Infecções por Escherichia coli/mortalidade , Infecções por Escherichia coli/fisiopatologia , Regulação da Expressão Gênica/imunologia , Vírus da Doença Hemorrágica de Coelhos/imunologia , Coelhos/microbiologia , Coelhos/virologia , Vacinação/normas
6.
Comp Immunol Microbiol Infect Dis ; 65: 165-175, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31300109

RESUMO

Avian influenza vaccines are commonly used in the poultry industry, and some medicinal plants can increase the efficacy of such vaccines. The objective of this study was to evaluate the effect of Immulant® (IMU) (a commercial product based on Echinacea and Nigella sativa) on stress induced by dexamethasone (DEX) in chickens vaccinated (VAC) against the H9N2 avian influenza virus (AIV-H9N2). Seven experimental groups were included: the negative control, VAC, DEX, VAC + DEX, VAC + DEX + IMU, VAC + IMU and IMU groups. The vaccinated chickens (at 10 days of age) were injected daily with DEX for three days pre-vaccination and for three days pre-challenge and orally administered 1% IMU for 6 weeks post-vaccination (PV). The chickens were then challenged intranasally with AIV-H9N2 at 28 days PV. Serum, blood, tracheal and cloacal swabs and tissue samples were collected in the 1st and 4th weeks PV and at different time points post-challenge. The results showed significant changes (P ≤ 0.05) in oxidative stress and antioxidant biomarkers (malondialdehyde, nitric oxide and reduced glutathione), haematological and immunological parameters, final live weights, relative organ weights and histopathological lesions between the VAC+DEX group and the VAC group. Moreover, IMU significantly increased protection rates post-challenge, HI antibody titers and heterophil phagocytic activity and decreased DEX-induced stress and virus shedding titers. In conclusion, oral administration of 1% IMU for six weeks can enhance the immune response after AI-H9N2 vaccination and reduce the pathogenicity of infection in stressed chickens.


Assuntos
Adjuvantes Imunológicos/administração & dosagem , Galinhas/imunologia , Echinacea/química , Vírus da Influenza A Subtipo H9N2/patogenicidade , Vacinas contra Influenza/imunologia , Nigella sativa/química , Adjuvantes Imunológicos/química , Animais , Anticorpos Antivirais/sangue , Dexametasona/administração & dosagem , Imunossupressão , Influenza Aviária/prevenção & controle , Influenza Aviária/virologia , Aves Domésticas , Estresse Fisiológico , Virulência , Eliminação de Partículas Virais
7.
Artigo em Inglês | MEDLINE | ID: mdl-31174705

RESUMO

This study was conducted to perform the comparative molecular characterization of avian influenza virus (AIV) H9N2, pathogenicity and seroprevalence in commercial and backyard poultry flocks. Fifty commercial poultry flocks were investigated between 2012 and 2015. Eighteen flocks (36%) out of 50 were positive HA. Seven (38.9%) out of 18 were positive by chromatographic strip test for AI common antigen. By Real-time RT-PCR, only two flocks were positive H9. The molecular characterization of two different AI-H9N2 viruses, one isolated from a broiler flock (A/chicken/Egypt/Mansoura-18/2013) and the other from a layer flock (A/chicken/Egypt/Mansoura-36/2015) was conducted on HA gene. Moreover, a higher seroprevalence, using the broiler strain as a known antigen, was shown in backyard chicken flocks 15/26 (57.7%) than duck flocks 9/74 (12.2%). Interestingly, the pathogenicity index (PI) of the H9N2 broiler strain in inoculated experimental chickens ranged from 1.2 (oculonasal route) to 1.9 (Intravenous route). The PI indicated a highly pathogenic effect, with high mortality (up to 100%) in the inoculated chickens correlated with the high mortality (80%) in the flock where the virus was isolated. The firstly recorded clinical signs, including cyanosis in the combs and wattles and subcutaneous haemorrhages in the leg shanks and lesions, as well as histopathology and immunohistochemistry, revealed a systemic infection of the high pathogenicity with the H9N2 virus. Conversely, the H9N2 layer strain showed a low pathogenicity. In conclusion, as a first report, the molecular analysis and pathogenicity of the tested strains confirmed the presence of a high pathogenicity AIV-H9N2 with systemic infections.


Assuntos
Vírus da Influenza A Subtipo H9N2/genética , Vírus da Influenza A Subtipo H9N2/patogenicidade , Influenza Aviária/virologia , Doenças das Aves Domésticas/virologia , Aves Domésticas/virologia , Animais , Galinhas/virologia , Cianose/virologia , Patos/virologia , Egito/epidemiologia , Influenza Aviária/mortalidade , Doenças das Aves Domésticas/mortalidade , Reação em Cadeia da Polimerase em Tempo Real , Estudos Soroepidemiológicos , Perus/virologia , Virulência
8.
Vet Microbiol ; 231: 24-32, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30955817

RESUMO

Avian influenza virus (AIV) H9N2 infection causes economic losses on poultry farms, and immunostimulants are essential for improving chicken immunity. This study evaluated the immunological and pathological effects of vitamin E with Fetomune Plus® (a commercial product based on a yeast extract and vitamins) on chickens experimentally infected with AIV H9N2. Three groups of white Hy-Line chicks were included. The G1 group was kept as an uninfected untreated control, the G2 group was intranasally infected with the AIV H9N2 strain (0.5 ml of 106 50% egg infectious dose (EID50)), and the G3 group was infected and treated with vitamin E (200 mg/kg of diet) and Fetomune Plus® (1 ml/liter of drinking water) for four weeks. The gene expression of interferon-gamma (IFN-γ), interleukin (IL)-6, and IL-2 was determined at 3, 5 and 7 days post-infection (PI). Virus shedding titers and rates and haemagglutination inhibition (HI) antibody titers were detected. Clinical signs, mortalities and post-mortem lesions were recorded. The birds were weighed, and relative organ weights were calculated. Tissue specimens were taken for histopathological examination and immunohistochemistry (IHC). The expression of IFN-γ in the duodenum revealed a significant increase in G2 compared to G3 at 3 days PI, while the duodenal and splenic expression of IL-6 was significantly increased in G2 compared to G3 at 5 days PI. IL-2 was overexpressed in the duodenum in G3 compared to G2 at 3 and 5 days PI. A significant decrease (P ≤ 0.05) in the virus shedding titer and an increase in the HI titers were detected in G3 compared to G2. The clinical signs and the mortality rate were clearly appeared in G2 than in G3. By IHC, lower H9N2 staining intensity was observed in the examined organs from G3 than in those from G2. In conclusion, as a first report, vitamin E with Fetomune Plus® supplementation for four weeks could improve the immunological and pathological effects of H9N2 infection on chickens.


Assuntos
Suplementos Nutricionais , Influenza Aviária/terapia , Doenças das Aves Domésticas/terapia , Vitamina E/imunologia , Ração Animal , Animais , Anticorpos Antivirais/sangue , Galinhas , Citocinas/imunologia , Testes de Inibição da Hemaglutinação , Imuno-Histoquímica , Vírus da Influenza A Subtipo H9N2 , Influenza Aviária/imunologia , Interferon gama/imunologia , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/virologia , Eliminação de Partículas Virais/efeitos dos fármacos , Vitamina E/administração & dosagem
9.
Vet Microbiol ; 219: 8-16, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29778208

RESUMO

Avian influenza and infectious laryngeotracheitis viruses are common causes of respiratory diseases in chickens with economical importance worldwide. In this study, we investigated the effect of experimental co-infection of avian influenza virus-H9N2 (AIV-H9N2) with infectious laryngeotracheitis virus (ILTV) live-attenuated vaccine (LAR-VAC®) on chickens. Four experimental groups were included in this study: negative control group, AIV-H9N2 group, AIV-H9N2+LAR-VAC® group, and LAR-VAC® group. AIV-H9N2 was inoculated intranasally to challenged groups at 35 days of age. On the same day, LAR-VAC® was ocularly administered to vaccinated groups. Chickens were observed for clinical signs, changes in body weight and mortality rates. Tissue samples, sera, tracheal and cloacal swabs, and blood were also collected at 3, 6, 9 and 12 days post-infection (PI). A significant increase in clinical signs and mortality rates were observed in the AIV-H9N2 + LAR-VAC® group. Moreover, chickens coinfected with AIV-H9N2 and LAR-VAC® showed a significant decrease in body weight and lymphoid organs indices. The tracheal gross and histopathological lesions and the shedding titer and period of AIV-H9N2 were significantly higher in AIV-H9N2 + LAR-VAC® group when compared to other groups. Furthermore, AIV-H9N2 infection leads to humoral and cellular immunosuppression as shown by a significant decrease in the CD4+/CD8+ ratio and antibody responses to ILTV and a significant increase in H/L ratio. In conclusion, this is the first report of co-infection of AIV-H9N2 and ILTV vaccine in chickens, which leads to increased pathogenicity, pathological lesions, and AIV-H9N2 shedding titer and period, which can lead to severe economic losses due to poor weight gain and mortality.


Assuntos
Coinfecção/veterinária , Influenza Aviária/virologia , Laringite/veterinária , Traqueíte/veterinária , Vacinação/efeitos adversos , Vacinas Atenuadas/efeitos adversos , Animais , Anticorpos Antivirais/sangue , Galinhas/imunologia , Galinhas/virologia , Coinfecção/imunologia , Coinfecção/virologia , Imunidade Celular , Imunidade Humoral , Imunossupressão , Vírus da Influenza A Subtipo H9N2/isolamento & purificação , Vírus da Influenza A Subtipo H9N2/patogenicidade , Vacinas contra Influenza/administração & dosagem , Influenza Aviária/etiologia , Influenza Aviária/imunologia , Influenza Aviária/mortalidade , Laringite/prevenção & controle , Laringite/virologia , Doenças das Aves Domésticas/virologia , Traqueíte/prevenção & controle , Traqueíte/virologia , Vacinas Atenuadas/administração & dosagem , Eliminação de Partículas Virais
10.
J Glob Antimicrob Resist ; 14: 202-208, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29684574

RESUMO

OBJECTIVES: Antimicrobial resistance in Salmonella serotypes has been reported. Integrons play an important role in the dissemination of antimicrobial resistance genes in bacteria. Scarce literature is available on the identification of integrons in Salmonella isolated from broiler chickens. In this study, antimicrobial susceptibility testing and characterisation of class 1 integrons among multidrug-resistant (MDR) Salmonella enterica serotypes in broiler chicken farms in Egypt were performed. METHODS: Antimicrobial susceptibility was determined by the disk diffusion method. PCR was performed to detect antimicrobial resistance genes and class 1 integrons in the tested Salmonella serotypes. Gene sequencing of the variable region of a class 1 integron was performed. RESULTS: Salmonella spp. were detected in 26 (13.5%) of 192 broiler samples, with Salmonella Enteritidis being the most frequently detected serotype, followed by Salmonella Kentucky and Salmonella Typhimurium and other serotypes. A very high resistance rate was observed to trimethoprim/sulfamethoxazole (100%), whilst a low resistance rate was observed to cefuroxime (57.7%). MDR S. enterica isolates displayed resistance to ciprofloxacin and azithromycin. Class 1 integrons were detected in 20 (76.9%) of the 26 Salmonella isolates. A high prevalence of class 1 integrons, as the first recorded percentage in the literature, associated with MDR Salmonella isolates was observed. CONCLUSIONS: Antimicrobial resistance rates in Salmonella serotypes from broiler chicken farms were alarming, especially for ciprofloxacin and azithromycin. Thus, another therapeutic strategy other than antimicrobials is recommended to prevent outbreaks of MDR Salmonella.


Assuntos
Galinhas/microbiologia , Farmacorresistência Bacteriana Múltipla , Integrons , Salmonella/classificação , Animais , Azitromicina/farmacologia , Cefuroxima/farmacologia , Ciprofloxacino , DNA Bacteriano/genética , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão , Egito , Filogenia , Salmonella/efeitos dos fármacos , Salmonella/genética , Salmonella/isolamento & purificação , Salmonella enterica/efeitos dos fármacos , Salmonella enterica/genética , Análise de Sequência de DNA , Sorogrupo , Combinação Trimetoprima e Sulfametoxazol/farmacologia
11.
Avian Pathol ; 47(2): 161-171, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28975807

RESUMO

This study was carried out on six laying hen farms, three mite-infested and three mite-free at Dakahlia and Damietta governorates in Egypt to demonstrate: (i) prevalence of different species of mites on laying hen farms; (ii) effects of mite infestation on chicken health and production; (iii) efficacy of deltamethrin (DMT) on treatment of mite infestation and (iv) residues of DMT in eggs and meat. The results showed that 12 mite species were detected in the mite-infested farms, this is the first record in Egypt, and that Dermanyssus gallinae was the highest identified species from 295 (40.9%) of 720 samples. There was a significant effect (P ≤ 0.05) of mites on the mortality %, feed consumption, egg production % and the tested haematological parameters. DMT had no impact on production performance, while transient respiratory signs post-spraying were recorded. The mites induced severe skin lesions. Egg samples showed the highest residue levels of DMT, followed by muscle and skin at P ≤ 0.05. It can be concluded that the mite species, as a first record, had a deleterious impact on the performance of the Egyptian laying hen farm facilities. Moreover, that DMT (Butox® 50 EC, Intervet Co., France) spraying was ineffective by one-time application, every 1 or 2 months in mite-infested laying hen farms, particularly when heavily infested. Furthermore, DMT residues in laying hen eggs and tissue should be considered to avoid the potential risk for humans.


Assuntos
Galinhas , Resíduos de Drogas , Inseticidas/uso terapêutico , Infestações por Ácaros/veterinária , Nitrilos/uso terapêutico , Doenças das Aves Domésticas/parasitologia , Piretrinas/uso terapêutico , Animais , Ovos/análise , Egito/epidemiologia , Fazendas , Feminino , Inseticidas/farmacocinética , Infestações por Ácaros/epidemiologia , Infestações por Ácaros/parasitologia , Ácaros/classificação , Músculo Esquelético/química , Músculo Esquelético/metabolismo , Nitrilos/farmacocinética , Oviposição , Doenças das Aves Domésticas/tratamento farmacológico , Doenças das Aves Domésticas/epidemiologia , Prevalência , Piretrinas/farmacocinética , Pele/química
12.
Vaccine ; 35(29): 3682-3689, 2017 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-28495316

RESUMO

BACKGROUND: Chickens infected with both infectious bursal disease virus (IBDV) and Salmonella had higher mortality. In this work, we investigated the effect of IBDV vaccine (modified live-virus bursal disease vaccine, Nobilis strain 228E®) on experimentally infected chickens with Salmonella Enteritidis (SE). METHODS: Four experimental groups were included in this study, negative control group, 228E®group, 228E®+SE infected group, and SE infected group. Chickens were ocularly administrated 228E® at 12days of age and orally infected with S. Enteritidis at 13days of age. Sera, intestinal fluid, blood, cloacal swabs and tissue samples were collected at 1, 2 and 3weeks post vaccination (PV). RESULTS: The recorded mortalities were higher in the 228E®+SE infected group, compared to the SE infected group. The anti-S. Enteritidis serum antibody titer and the intestinal mucosal IgA level were higher in the SE infected group at 2 and 3weeks PV, compared to 228E®+SE infected group. S. Enteritidis fecal shedding and organ colonization were significantly higher in the 228E®+SE infected group than the SE infected group at 2 and 3weeks PV. The 228E®+SE group had significantly lower bursa to body weight ratios at 2 and 3weeks PV, as well as had higher bursal lesion scores than the SE infected group. IBDV vaccine depressed the specific-SE systemic and mucosal antibody responses, but did not affect the specific-SE cellular immune responses. CONCLUSION: Chickens administrated IBDV vaccine, followed by S. Enteritidis infection, could cause a significant effect on the bursa of Fabricius, resulting in failure of systemic and mucosal antibody responses to the S. Enteritidis and reduce the elimination and the clearance of S. Enteritidis.


Assuntos
Infecções por Birnaviridae/veterinária , Coinfecção/veterinária , Vírus da Doença Infecciosa da Bursa/imunologia , Doenças das Aves Domésticas/mortalidade , Doenças das Aves Domésticas/prevenção & controle , Salmonelose Animal/mortalidade , Vacinas Virais/imunologia , Experimentação Animal , Animais , Infecções por Birnaviridae/complicações , Infecções por Birnaviridae/mortalidade , Infecções por Birnaviridae/prevenção & controle , Galinhas , Coinfecção/mortalidade , Coinfecção/prevenção & controle , Salmonelose Animal/complicações , Análise de Sobrevida , Vacinas Virais/administração & dosagem , Vacinas Virais/efeitos adversos
13.
Vet Res Commun ; 38(3): 237-47, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24993748

RESUMO

The consequence of cryptosporidiosis on the immune response of vaccinated chickens against Newcastle disease and/or avian influenza was studied by using 240, 1 day old, male, white Hy-Line chicks and divided into 8 groups and subgroups. Each group or subgroup was consisting of 30 chicks (15 × 2 replicates). The first and second groups were kept as unvaccinated control, G1uninfected and G2 infected. G3, G4 and G5 contained 2 subgroups A&B (G3A, G3B, G4A, G4B, G5A and G5B). Chicks of subgroup A were vaccinated only while chicks of subgroup B were infected and vaccinated. These chicks were orally inoculated with 5 × 10(5) oocysts of Cryptosporidium baileyi (C. baileyi) at 2 days of age. Chickens were vaccinated intraocular with live Newcastle disease (ND) vaccine (Hitchner on day 7th and LaSota on day 17th of chicken life) (G3) or vaccinated by subcutaneous route with Volvac®- H5N2- AI vaccine on day 10 of chicken life (G4). Last group (G5) was infected similarly and vaccinated with ND and AI vaccines with the same day, dose and route of vaccination for each one. Random blood samples were collected for 3 weeks post-vaccination for investigation of humoral immune response against Newcastle and/or avian influenza vaccines by the haemagglutination inhibition (HI) test. The results showed that H5N2 vaccine at day 10 of chicken life is effective in chickens indicated by the geometric mean of HI titer against AI virus. The findings of this study showed that the infection with Cryptosporidia in the broiler chicken has a depressive effect on the immune status of the birds vaccinated against ND and/or AI vaccination. Moreover, the obtained protection rates against challenge with virulent ND virus observed to be parallel to the results of HI- test. Also, by using 2 different antigens (one commercial and field prepared antigen) to avian influenza virus, lower Geometric mean (GM) HI titer were appeared in infected and vaccinated group than vaccinated group only. A study of the relative lymphoid organs weight such as bursa of Fabricius from the experimental chicks indicated that those organs were comparable between the groups infected-vaccinated and vaccinated only. Non significant variations in final live weight between uninfected control and infected groups were indicated. Also, H5N2-AI vaccination at 10 days old did not affect the final live weight. ND and/or AI Vaccination could not be a substitute to application of good hygienic measures and fecal examination of the birds especially for protozoal diseases such as cryptosporidiosis. It could be concluded that cryptosporidiosis could be one cause of ND and/or AI vaccination failure in poultry farms.


Assuntos
Criptosporidiose/imunologia , Vacinas contra Influenza/administração & dosagem , Influenza Aviária/prevenção & controle , Criação de Animais Domésticos , Animais , Anticorpos Antivirais/sangue , Galinhas , Testes de Inibição da Hemaglutinação , Imunidade Humoral/imunologia , Vírus da Influenza A Subtipo H5N2/imunologia , Vacinas contra Influenza/imunologia , Vacinas contra Influenza/normas , Masculino , Doença de Newcastle/prevenção & controle , Vírus da Doença de Newcastle/imunologia
14.
Vet Microbiol ; 167(3-4): 651-61, 2013 12 27.
Artigo em Inglês | MEDLINE | ID: mdl-24139721

RESUMO

The highly pathogenic avian influenza (HPAI) H5N1 in Egypt circulated continuously after its introduction in February 2006 with substantial economic losses and frequent human infections. Phylogenetic analysis of the available HA sequences revealed the presence of two main sublineages; the classic 2.2.1 and the variant 2.2.1.1. The classic 2.2.1 had subdivided into two clusters of viruses; cluster C1 contained the originally introduced virus and isolates from 2006 to 2009 and cluster C2 emerged in 2007 and continues to circulate. The variant 2.2.1.1 represents the isolates mainly from chickens and subdivided into two clusters; cluster V1 contains isolates from 2007 to 2009 and cluster V2 contains isolates from 2008 to 2011. Sequence analysis revealed 28 amino acid mutations in the previously reported antigenic sites and high evolution rate which may be due to selective pressure from vaccination and/or natural infection. Antigenic analysis of 18 H5N1 isolates from 2006 to 2012 that represent different clusters was conducted using hemagglutination inhibition (HI) and virus neutralization (VN) assays using hyperimmune sera produced by immunizing SPF chickens with inactivated whole-virus. Antigenic relatedness of ancestral Egyptian H5N1 isolate (459-3/06) with other isolates ranged from 30.7% to 79.1% indicating significant antigenic drift of the H5N1 viruses from the ancestral strains. The antigenic relatedness between C2 and V2 clusters ranged from 28.9% to 68% supporting the need for vaccine seed strains from both clusters. Interestingly, A/CK/EG/1709-6/2008 H5N1 strain showed a broad cross reactivity against viruses in different H5N1 clusters (antigenic relatedness ranged from 63.9% to 85.8%) demonstrating a potential candidate as a vaccine strain. Antigenic cartography which facilitates a quantitative interpretation and easy visualization of serological data was constructed based on HI results and further demonstrated the several antigenic groups among Egyptian H5N1 viruses. In conclusion, the cross reactivity between the co-circulating H5N1 strains may not be adequate for protection against each other and it is recommended to test vaccines that contain isolates from different antigenic groups in experimental infection trials for the selection of vaccine seed strain. Furthermore, the continuous monitoring for detecting the emerging variants followed by detailed antigenic analysis for updating vaccines is warranted.


Assuntos
Antígenos Virais/genética , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Virus da Influenza A Subtipo H5N1/genética , Virus da Influenza A Subtipo H5N1/imunologia , Influenza Aviária/virologia , Filogenia , Doenças das Aves Domésticas/virologia , Sequência de Aminoácidos , Animais , Antígenos Virais/imunologia , Egito , Virus da Influenza A Subtipo H5N1/isolamento & purificação , Influenza Aviária/imunologia , Aves Domésticas/virologia , Doenças das Aves Domésticas/imunologia , Alinhamento de Sequência
15.
Vet Microbiol ; 162(2-4): 353-359, 2013 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-23123174

RESUMO

Frequent transmission of swine influenza viruses (SIVs) to turkeys has been reported since 1980s. Experimental studies also showed that SIVs can infect turkeys with varying replication and transmission efficiency depending on the strain. However, host factors involved in infection/replication efficiency remain unclear. To investigate whether the immune status of turkeys might play a role in the susceptibility of turkeys to SIVs, we studied the replication efficiency of two recent SIVs (human-like H1N2 and triple reassortant (TR) H3N2) in dexamethasone-treated turkeys. The viruses were inoculated intranasally in both dexamethasone-treated and untreated control juvenile and layer turkeys. Amount of virus shedding was monitored at 2, 4, and 7 days post inoculation (DPI). Additionally, passage of both viruses was attempted in dexamethasone-treated 4-week-old turkeys. In both juvenile and layer turkeys, we were able to detect human-like H1N2 SIV only from dexamethasone-treated turkeys and no virus was detected in untreated birds. The virus shedding of the TR H3N2 SIV was also consistently higher (≈ 1 Log(10)EID(50)/ml) in dexamethasone-treated birds in both tracheal and cloacal swabs compared to untreated birds. Virus passage in dexamethasone-treated turkeys was successful up to the second passage and no virus was recovered from the third passage. These results show that potential immunosuppression due to dexamethasone treatment may enhance the transmission and adaptation of SIVs in turkeys through enhancement of virus replication, prolonged virus shedding, and possible decrease of infectious dose required to initiate infection.


Assuntos
Dexametasona/farmacologia , Vírus da Influenza A Subtipo H1N2/fisiologia , Vírus da Influenza A Subtipo H3N2/fisiologia , Influenza Aviária/virologia , Doenças das Aves Domésticas/virologia , Replicação Viral/efeitos dos fármacos , Adolescente , Animais , Cães , Humanos , Células Madin Darby de Rim Canino , Sus scrofa , Suínos , Perus , Eliminação de Partículas Virais
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