Following the avian influenza epidemics that occurred in Italy between 1997 and 2003, the Italian Ministry of Health in collaboration with veterinary authorities promoted, funded and implemented a national surveillance programme. The main objectives of the surveillance effort were to identify avian influenza viruses circulating in wild birds and to investigate the role of backyard poultry flocks in the dynamics of infection in a densely populated poultry area. Over 2 years (2004 to 2006), 164 backyard flocks and 4083 wild birds (mainly migratory Anseriformes and Charadriiformes) were sampled in three regions in the North of Italy. Samples collected were screened by means of real-time reverse transcriptase-polymerase chain reaction and the positive samples were processed for attempted virus isolation in embryonated fowl's specific pathogen free eggs. At the end of the study period, 27 low-pathogenic avian influenza viruses had been isolated from backyard flocks and 49 strains obtained from wild birds. Of these, 26 belonged to the H5 or H7 subtype and were closely related to contemporary low-pathogenic strains of Eurasian lineage. The findings confirm that backyard free-range farming is at high risk for avian influenza virus introduction, and confirm the role of wild waterfowl in the introduction and perpetuation of low-pathogenic avian influenza viruses during the winter season in Southern Europe.

A fatal Encephalomyocarditis virus (EMCV) infection epidemic involving fifteen primates occurred between October 2006 and February 2007 at the Natura Viva Zoo. This large open-field zoo park located near Lake Garda in Northern Italy hosts one thousand animals belonging to one hundred and fifty different species, including various lemur species. This lemur collection is the most relevant and rich in Italy. A second outbreak between September and November 2008 involved three lemurs. In all cases, the clinical signs were sudden deaths generally without any evident symptoms or only with mild unspecific clinical signs. Gross pathologic changes were characterized by myocarditis (diffuse or focal pallor of the myocardium), pulmonary congestion, emphysema, oedema and thoracic fluid. The EMCV was isolated and recognized as the causative agent of both outbreaks. The first outbreak in particular was associated with a rodent plague, confirming that rats are an important risk factor for the occurrence of the EMCV infection.

Between 2002 and 2007, more than 1000 chickens from commercial farms, live bird markets and backyard farms in Nigeria and Niger were tested for the presence of the infectious bronchitis virus (IBV) genome. Phylogenetic analysis of full-length sequences of the spike 1 (S1) gene revealed a new genotype of IBV that we refer to as 'IBADAN'. The minimum genetic distance to the closest 'non-IBADAN' strains (UK/7/93 at the nucleotide level; H120 and M41 at the amino acid level) reached 24 and 32 % at the nucleotide and amino acid levels, respectively. The full genome of the IBADAN reference strain (NGA/A116E7/2006) had a genetic distance of 9.7-16.4 % at the nucleotide level with all available fully sequenced strains. As IBV S1 plays a major role in antigenicity, the antigenic relatedness of NGA/A116E7/2006 was compared with strains of other serotypes. NGA/A116E7/2006 did not cross-react with antisera against IT02, M41, D274, Connecticut or 793/B strains in virus neutralization assays. NGA/A116E7/2006 cross-reacted with the QX-like strain ITA/90254/2005 but only to a low level (antigenic relatedness of 33 %), suggesting that IBADAN also represents a new serotype. A comparison of S1 sequences identified several amino acids that may play a role in IBV antigenicity. Despite the absence of obvious clinical signs in poultry infected by IBADAN strains, it is important to test the crossprotection of current vaccine strains.

Avian influenza infections by high and low pathogenicity H7 influenza viruses have caused several outbreaks in European poultry in recent years, also resulting in human infections. Although in some cases the source of H7 strains from domestic poultry was shown to be the viruses circulating in the wild bird reservoir, a thorough characterization of the entire genome of H7 viruses from both wild and domestic Eurasian birds, and their evolutionary relationships, has not been conducted. In our study, we have analysed low pathogenicity H7 influenza strains isolated from wild and domestic ducks in Italy and southern China and compared them with those from reared terrestrial poultry such as chicken and turkey. Phylogenetic analysis demonstrated that the H7 haemagglutinin genes were all closely related to each other, whereas the remaining genes could be divided into two or more phylogenetic groups. Almost each year different H7 reassortant viruses were identified and in at least two different years more than one H7 genotype co-circulated. A recent precursor in wild waterfowl was identified for most of the gene segments of terrestrial poultry viruses. Our data suggest that reassortment allows avian influenza viruses, in their natural reservoir, to increase their genetic diversity. In turn this might help avian influenza viruses colonize a wider range of hosts, including domestic poultry.

Five chicken lines were experimentally infected with a HPAI H7N1 virus, to examine the variation in susceptibility to infection. Three lines showed high susceptibility to the virus, while two showed some resistance, with 7 out of 20, and 11 out of 15 birds, respectively, remaining healthy and surviving the experimental infection. Genotyping for the G/A polymorphism at position 2032 of Mx cDNA showed that one line was fixed for the G allele, and two were segregating for A and G alleles. Birds in the other two lines were selected to be fixed for the A allele. Statistical analyses indicated that the Mx genotype did not affect the clinical status or the time course of infection after viral inoculation.

The isolation of four new variants or serotypes of avian infectious bronchitis virus in Italy is reported. The antigenic characteristics of these strains were investigated by cross-neutralization tests with the new isolates, Fa 6881/97, AZ 27/98, AZ 20/97, and BS 216/01; two of the most common European serotypes, AZ 23/74 and CR 88121 (793B); and the classic Massachusetts M41 serotype in association with a panel of 17 specific antisera. On the basis of the results obtained, the new isolates show relevant serologic differences. In fact, the four isolates were not neutralized by antisera against the most common European and American serotypes; the AZ 20/97 isolate was partially neutralized by FA 6881/97 antiserum but not reciprocally. The closely related Fa 6881/97 and AZ 27/98 isolates can be considered rather diffused in our country because they have been isolated over 20 times in the last 3 yr in different parts of Italy. On the contrary, the AZ 20/97 and BS 216/01 isolates were reported only once so far. The reverse transcription-polymerase chain reaction showed that Fa 6881/97 isolate is related to 793B isolate, whereas AZ 27/98 and BS 216/01 isolates appeared not to be related to the most common European and Massachusetts serotypes.

Porcine epidemic diarrhoea (PED) is a contagious enteric disease of pigs caused by a coronavirus. A double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) based on the use of monoclonal antibodies was developed for the detection of porcine epidemic diarrhoea virus (PEDV). The DAS-ELISA was compared with RT-PCR in the examination of 506 specimens collected during 2006-2007 from pigs originating from different farms located in the Po valley. Both faecal samples obtained directly from the rectum of live animals showing clinical signs and intestinal samples collected from the caecum of deceased pigs were included in the study. The correlation between the two methods was higher when testing faecal samples (K=0.97, 95% CI: 0.94-1.00) than testing intestinal samples (K=0.62, 95% CI: 0.35-0.89). The use of ELISA technology provided an efficient and effective mean of evaluating the presence of coronavirus PED antigen in field samples and indicates that this procedure is a very useful tool in epidemiological studies.

Although wild boar can act as a persistent Aujeszky's disease (AD) reservoir, limited data are available on long-term epidemiology in free-ranging wild boar living in areas where industrial swine herds are limited. Hence, this study provides crucial information, which fills this knowledge gap, on the natural dynamics of AD infection. From 3260 sera sampled during eight hunting seasons, 162 (4.97%) were tested positive. Factors, including the animal's age class, and the sampling year, had significant effects on the probability of the wild boar being seropositive, while wild boar mean abundance per area, yearly abundance and the total number of pig farms, as well as interactions among age, year and sex, were not significant. In particular, a positive trend of seroprevalence was observed over the years, with values ranging from 2.1 to 10.8%. This long-term surveillance showed an increase in seroprevalence with a higher probability of being seropositive in older individuals and the independence of wild boar seropositivity from the likelihood of contact with pigs in the area.