1,720,973 research outputs found
Epidemiology of Avian Metapneumovirus Infection in Italy
No full textAt the beginning of 2000 little information was available on circulation and molecular epidemiology of AMPV Italian poultry except for the data regarding the first Italian isolates made in the late 80s, which were shown to be B subtypes (Juhasz and Easton, 1994; Sperati Ruffoni L., personal communication). Moreover even though the vaccination was widely applied, disease still occurs occasionally in young as well older turkeys. This paper reports some studies performed in Italy since 2001 in order to understand better the epidemiology of AMPV and prophylactic problems encountered in the field
Impiego della tecnica ELISA per l'indagine epidemiologica della Enterite emorragica del tacchino.
No full text
Impiego della tecnica ELISA per l'indagine epidemiologica della Enterite emorragica del tacchino.
No full textSerological evaluation of a vaccination protocol for swine influenza virus in fattening pigs
No full textSwine Influenza Virus (SIV) a type A Orthomyxovirus is responsible for Swine Influenza, an acute infectious disease responsible for severe economic losses for pig producers. Three antigenically distinct subtypes H1N1, H3N2 and H1N2 can be found in the pig. The aim of this study was to evaluate the efficacy of a third vaccination administered at 6 months of age. Italian pigs are in fact slaughtered at 9 months of age at a weight >150 kg, and classic vaccination schemes do not induce a high immunity level till throughout the growing period
Discriminazione rapida fra ceppi vaccinali e di campo di Metapneumovirus aviare mediante tecnica RFLP
No full textIn Italia l’infezione da Metapneumovirus aviare (AMPV) si è diffusa a partire dal 1987. Successivamente si è endemizzata nelle Regioni a maggior vocazione avicola, con prevalenza del sottotipo B. Per il controllo delle infezioni da AMPV nell'allevamento del tacchino sono utilizzati vaccini vivi attenuati; fra quelli disponibili nel nostro Paese è diffuso l’utilizzo del sottotipo B, somministrato nei tacchini da carne, via spray, in incubatoio. E’ stato dimostrato che ceppi vaccinali possono essere evidenziati tramite RT-PCR fino alla quarta settimana di età, associati o meno a sintomatologia respiratoria. In presenza di forme cliniche risulta necessario poter discriminare tra ceppi di campo e di origine vaccinale.
L'analisi della sequenza del gene G di numerosi ceppi AMPV sottotipo B isolati in varie aree geografiche del mondo, ha rivelato la presenza, nella sola sequenza del vaccino B (ceppo VCO3) maggiormente utilizzato in Italia, di un sito di riconoscimento dall’enzima di restrizione Msel. Tale sito è localizzato nell'amplicone che si ottiene con il protocollo di RT nested-PCR messo a punto da Naylor et al., e comunemente impiegato in Europa per la diagnosi delle infezioni da AMPV e la distinzione fra sottotipi A e B.
Basandosi su queste evidenze, è stato messo a punto e testato su alcuni AMPV isolati in Italia un protocollo di PCR-Restriction Fragment Length Polymorphism (RFLP) in grado di discriminare fra ceppi sottotipo B di campo e vaccinali
Valutazione sierologica dell’efficacia di un protocollo vaccinale per influenza suina in soggetti all’ingrasso
No full textLa risposta anticorpale specifica nei confronti dei sottotipi H1N1 e H3N2 del virus dell’influenza suina (SIV) è stata valutata in due gruppi di soggetti sottoposti a piani vaccinali diversi. In particolare, è stata valutata la sieroconversione dei soggetti a cui è stato praticato un 3° intervento vaccinale in coincidenza con quello previsto a 6 mesi di vita contro il virus della Malattia di Aujeszky. Il terzo intervento vaccinale determina un incremento significativo (P<0,05) dei titoli anticorpali specifici anti H1N1 e anti SIV inducendo così un più elevato grado di protezione nelle fasi finali del ciclo di produzione
Avian Metapneumovirus, Hemorrhagic Enteritis Virus and Avian Pathogenic Escherichia coli (APEC) interaction in a finishing turkey farm subjected to colibacillosis-associated mortality
No full textThe spectrum of pathogens responsible for colibacillosis-associated mortality is investigated by longitudinal surveys performed in three consecutive production cycles of a finishing toms farm. The surveys mainly focus on the interaction between Avian Metapneumovirus (AMPV), Haemorrhagic Enteritis Virus (HEV) and Avian Pathogenic Escherichia Coli (APEC). Rhino-pharyngeal swabs, cloacal swabs and blood samples were weekly collected for AMPV and HEV PCR detection, and antibody response evaluation, until birds were 14-weeks-old. Mortality was reported and dead birds were examined post mortem. When colibacillosis was suspected, microbiological tests were performed from selected organs. All detected E. coli strains were serotyped and assessed for the presence of virulence-associated genes. In the first cycle, colisepticaemia associated mortality was recorded at week 4, due to AMPV and APEC O78. Late high O78 or O2 APEC associated mortality was observed respectively in the second and third cycle; these outbreaks were correlated to both HEV and AMPV infections
Epidemiology of Avian pathogenic Escherichia coli (APEC) in a finisching male turkey farm: longitudinal survey of three consecutive production cycles.
No full textThe purpose of this study was to investigate the epidemiology of APEC (Avian Pathogenic Escherichia coli), in a finishing male turkey commercial farm, conducting longitudinal surveys of three consecutive production cycles. The diversity and the distribution of APEC strains during the production cycles were examined using microbiological and molecular techniques. APEC isolates were serotyped, assessed for the presence of virulence-associated genes (pathogenic potential – pathotype) and for resistance to antibiotics (resistotype). Random Amplified Polymorphic DNA (RAPD) was applied to analyse their genetic relationship. Strains of high genetic homology were grouped into the same RAPD cluster (RAPD type).
Sampling included, when colisepticemic or articular lesions were observed, viscera and joints from day one until 14 weeks.
In the first cycle, APEC O78 was the most prevalent serotype with all isolates sharing the same resistotype and pathotype. Seven of them were included in the same RAPD cluster indicating high genetic similarity. In this cycle, APEC O111 was detected and this represents, to our knowledge,
In the second cycle, APEC O2 isolates predominated at the beginning, while O78 strains appeared later until the end of the survey. APEC O2 were classified in two resistotypes, same pathotype and RAPD type. APEC 078 belonged to three resistotypes, same pathotype and three RAPD types. APEC O78 strains, differently from serotype O2, were detected from both colisepticemic viscera (such as brain, pericardium, lungs) and joints. The articular tropism of this serotype is unique as it was observed only in APEC O78 strains of this cycle and of the previous one. Moreover, RAPD molecular studies identified a specific articular O78 cluster, including two strains, which was different from other RAPD clusters including O78 and O2 colisepticemic strains
Phylogenetic analysis of ORF5 and ORF7 sequences of porcine reproductive and respiratory syndrome virus (PRRSV) from PRRS-positive Italian farms: A showcase for PRRSV epidemiology and its consequences on farm management.
No full textWe investigated the dynamics of porcine reproductive and respiratory syndrome virus (PRRSV) variability in a range of swine PRRS-positive farms located in Northern Italy, to provide insights into the epidemiology and diffusion of the virus, particularly throughout the entire swine production chain. In this context, we also examined the effectiveness and the critical points of a recently developed gilts acclimatization program in swine breeder farms. To achieve these aims, we designed new primers and determined 64 complete open reading frame 5 (ORF5) sequences, representing Italian PRRSV field strains and the European vaccine Porcilis strain (Intervet); in addition, the more conserved ORF7 of 11 PRRSV strains were sequenced. The domains' prediction of their putative protein sequences was performed as well. Based on these sequences, phylogenetic trees were inferred which revealed a high degree of variability among the PRRSV Italian strains. The outcomes of the phylogenetic analysis showed that the most frequent source of infection in PRRS-positive farms (sow herds, nursery sites, fattening units) was the introduction of animals carrying a new variant and not the modification of already present variants; moreover, the integration of data from phylogenetic analysis and from the clinical and serological status of the swine herds suggested that the acclimatization program could be a valid tool to stabilize the PRRS clinical picture in farms, only when applied in combination with rigorous bio-security routine management and avoid the incoming of new PRRSV variants
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