The aims of this study were firstly to evaluate the pathogenicity of an Italian isolate of the QX strain of infectious bronchitis (IB) virus using 1-day-old female specific pathogen free chicks (layer type) and 1-dayold female commercial broiler type chickens, and secondly to assess the level of protection induced in these birds by a vaccination programme including the IB Massachusetts and 4/91 serotype live attenuated vaccines. Unvaccinated birds showed clinical signs of varying severity, predominantly affecting the upper respiratory tract. Vaccinated birds appeared healthy, with the exception of a very mild conjunctivitis affecting a limited number of the broilers. Vaccination fully protected specific pathogen free birds, since no histopathological lesions were observed, nor was virus detected following challenge. In broilers, replication of the challenge virus was not prevented but was significantly reduced. This study confirms that vaccination at 1 day old and at 14 days of age using the Ma5 and 4/91 IB vaccines may be instrumental in reducing the economic impact of QX IB virus infections in layer and broiler farms.
The recent outbreaks of avian influenza (AI) worldwide have highlighted the difficulties in controlling this disease both in developed and in developing countries. Biosecurity is considered the most important tool to prevent and control AI. In certain areas of the world, AI has become endemic and the recent outbreaks in Europe and Africa show that the epidemiological situation is evolving in an unprecedented way. The consequences of this situation are economic losses to the poultry industry, food security issues in developing countries and a serious threat to human health, due to the direct consequences of AI infection in humans, and more alarmingly due to the risk of the generation of a new pandemic virus from the animal reservoir. In this paper, the physical and chemical methods of inactivating AI viruses are reviewed, with particular emphasis on the practicalities of using such methods in the poultry industry.
Isolate wigeon/Italy/3920-1/2005 (3920-1) was obtained during surveillance of wild birds in November 2005 in the Rovigo province of Northern Italy and shown to be a paramyxovirus. Analysis of cross-haemagglutination-inhibition tests between 3920-1 and representative avian paramyxoviruses showed only a low-level relationship to APMV-1. Phylogenetic analysis of the whole genome and each of the six genes indicated that while 3920-1 grouped with APMV-1 and APMV-9 viruses, it was quite distinct from these two. In the whole-genome analysis, 3920-1 had 52.1 % nucleotide sequence identity to the closest APMV-1 virus, 50.1 % identity to the APMV-9 genome, and less than 42 % identity to representatives of the other avian paramyxovirus groups. We propose isolate wigeon/Italy/3920-1/2005 as the prototype strain of a further APMV group, APMV-12.
Small ruminant lentivirus infections in goats affect both production and animal welfare. This represents a threat to the qualitative and quantitative growth of goat farming, recently observed in mountainous regions such as the Autonomous Province of Bolzano – South Tyrol (Italy). To monitor and eradicate the caprine arthritis encephalitis virus in this goat population, a compulsory eradication campaign was launched, based on a strict census of small ruminants and yearly serological testing of all animals, followed by the consequent culling of seropositive individuals. The campaign succeeded in completely eliminating cases of clinical disease in goats, while drastically reducing the seroprevalence at the herd as well as individual animal level. The serological outcome of the introduced control measures was determined using commercially available ELISA kits, demonstrating their suitability for use in this type of campaign, aimed at reducing seroprevalence as well as clinical manifestations of these infections. However, this clear success is diminished by the failure to achieve a complete eradication of these viruses. The reasons leading to the observed tailing phenomenon and the occurrence of new infections in already sanitised flocks are discussed and implementation of further measures are proposed.
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