Circulation dynamics of Salmonella enterica subsp. enterica ser. Gallinarum biovar Gallinarum in a poultry farm infested by Dermanyssus gallinae.

Dermanyssus gallinae (Mesostigmata: Dermanyssidae, De Geer, 1778) is an ectoparasite of poultry, suspected to play a role as a vector of Salmonella enterica subsp. enterica ser. Gallinarum. Despite an association between them being reported, the actual dynamics in field remain unclear. Therefore, the present study aimed to confirm the interactions among mites, pathogen and chickens. The study was carried out in an industrial poultry farm infested by D. gallinae, during an outbreak of fowl typhoid. The presence of S. Gallinarum in mites was assessed and quantified by a semi-nested polymerase chain reaction (PCR) and real-time PCR, respectively, in mites collected during two subsequent productive cycles and the sanitary break. The anti-group D Salmonella antibodies were quantified by an enzyme-linked immunosorbent assay. During the outbreak and the sanitary break, S. Gallinarum was constantly present in mites. In the second cycle, scattered positivity was observed, although hens did not exhibit signs of fowl typhoid, as a result of the vaccination with BIO-VAC SGP695 (Fatro, Ozzano Emilia Bo, Italy). The data strongly suggest that D. gallinae acts as reservoir of S. Gallinarum, thus allowing the pathogen to persist in farms. Furthermore, the present study has highlighted the interactions among D. gallinae, S. Gallinarum and hens with respect to enhancing the mite-mediated circulation of S. Gallinarum in an infested poultry farm.

Efficacy of a novel neem oil formulation (RP03™) to control the poultry red mite Dermanyssus gallinae.

Dermanyssus gallinae (Mesostigmata: Dermanyssidae) is the most harmful ectoparasite of laying hens, represents an occupational hazard for poultry workers, and a growing threat to medical science per se. There is increasing demand for alternative products, including plant-derived acaricides, with which to control the mite. The present study investigated the efficacy of neem oil against D. gallinae on a heavily infested commercial laying hen farm. A novel formulation of 20% neem oil, diluted from a 2400-p.p.m. azadirachtin-concentrated stock (RP03™), was administered by nebulization three times in 1 week. Using corrugated cardboard traps, mite density was monitored before, during and after treatment and results were statistically analysed. Mite populations in the treated block showed 94.65%, 99.64% and 99.80% reductions after the first, second and third product administrations, respectively. The rate of reduction of the mite population was significantly higher in the treated block (P < 0.001) compared with the control and buffer blocks. The results suggest the strong bioactivity of neem, and specifically of the patented neem-based formulation RP03™, against D. gallinae. The treatment was most effective in the 10 days following the first application and its effects persisted for over 2 months. Further studies will aim to overcome observed side effects of treatment represented by an oily layer on equipment and eggs.

Polyomavirus Infection in Gouldian Finches (Erythrura gouldiae) and Other Pet Birds of the Family Estrildidae.

A syndrome characterized by apathy, diarrhoea and high mortality of nestlings was observed in a flock of pet birds of the family Estrildidae. Enlargement of the liver, pulmonary congestion and urate accretions in the kidney were observed. Microscopically, there was glomerular atrophy, oedema and congestion of the lungs and necrosis and fibrosis of the liver. Cowdry type B intranuclear inclusion bodies were detected in the tissues. Polyomavirus was detected by polymerase chain reaction. The entire genome of the virus was amplified and sequenced, revealing 99 % identity to the sequence of finch polyomavirus isolated from the Eurasian bullfinch (family Fringillidae).

Detection of the new emerging rabbit haemorrhagic disease type 2 virus (RHDV2) in Sicily from rabbit (Oryctolagus cuniculus) and Italian hare (Lepus corsicanus).

Rabbit haemorrhagic disease virus (RHDV), a member of the genus Lagovirus, causes rabbit haemorrhagic disease (RHD), a fatal hepatitis of rabbits, not previously reported in hares. Recently, a new RHDV-related virus emerged, called RHDV2. This lagovirus can cause RHD in rabbits and disease and mortality in Lepus capensis (Cape hare). Here we describe a case of RHDV2 infection in another hare species, Lepus corsicanus, during a concurrent RHD outbreak in a group of wild rabbits. The same RHDV2 strain infected rabbits and a hare, also causing a RHD-like syndrome in the latter. Our findings confirmed the capability of RHDV2 to infect hosts other than rabbits and improve the knowledge about the epidemiology and the host range of this new lagovirus.

Virulence-associated genes in avian pathogenic Escherichia coli from laying hens in Apulia, Southern Italy.

1. Escherichia coli isolated from lesions (Avian Pathogenic E. coli - APEC) of layer hens affected by colibacillosis and from intestinal contents of clinically-healthy birds (Avian Faecal E. coli - AFEC) were serotyped. All the isolates were investigated for the presence of virulence genes to determine which genes were more closely related to those from lesions. 2. A number of different serogroups were detected, O78 being predominant among the isolates from colibacillosis. 3. E. coli isolated from lesions were not linked to a specific pathotype (set of common virulence genes). 4. The presence of the virulence genes, with the exception of astA, was associated more generally with APEC strains. 5. Statistically, genes such as cva/cvi, tsh, iss, irp2 and iucD were more related to isolates from colibacillosis. 6. It is suggested that the detection of these genes in a rapid and inexpensive test for field practitioners could provide useful information about the potential virulence of E. coli isolated in commercial layer flocks.

Epidemiology and risk factors for dermatophytoses in rabbit farms.

While dermatophytoses of several animal species have been extensively investigated, information on their occurrence and epidemiology in rabbits is limited. We carried out a study from October 2006 to February 2007 of 23 rabbit farms in Apulia and Basilicata regions (southern Italy) in order to investigate the occurrence and risk factors associated with dermatophytoses in breeding rabbits. Dermatophytes were isolated from 86.9% (20/23) of the farms and from 51.8% (420/810) of the animals sampled. Trichophyton mentagrophytes (47.9%) and Microsporum canis (3.2%) were isolated from diseased (71.7%) and healthy (48.4%) animals as well from the surrounding environment (7.5%). The occurrence of lesions, the age of rabbits, and farm management (e.g., temperature, humidity and methods and frequency of disinfection practices) were identified as the most significant risk factors (P < 0.05) for the occurrence of dermatophytes. Animals in fattening and finishing stages were the most frequently infected (i.e., 58.2 and 61.6% respectively). Dermatophyte prevalence was significantly (P < 0.05) higher in areas with higher temperature (>20°C) and relative humidity ranging from 62-65%. The results of the present investigation suggest that zoonotic dermathophytes are present in rabbit farms and highlight the importance of correct management procedures for the control of the infections.