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A study was carried out by ANSES and the Technical Center for Animal Production (CTPA) in fifty broiler turkey farms in the Great West. In 68% of farms, there were digestive problems in turkeys, most often non-specific enteritis.
Rozen Souillard, epidemiologist (Anses Ploufragan): “TCoV circulates in turkey farms with or without digestive problems. »
“The presence of antibodies against the TCoV virus was noted in seven batchesof which for four of them also viral detection by PCR”, indicates Rozenn Souillard, of ANSES. It is therefore 14% of the batches that have encountered the virus.
TCoV is the main viral agent of multifactorial enteric diseases which mainly affects turkeys less than six weeks old, but potentially all ages. The clinical signs are diarrhoea, lethargy and anorexia resulting in growth retardation.
Paul Brown, virologist (Anses Ploufragan). “This virus is very infectious (transmission time between turkeys of 2.5 hours on average) and is excreted by the infected turkey for at least six weeks. »
“The virus is very infectious (transmission time between turkeys of 2.5 hours on average) and is excreted for at least six weeks”, underlined Paul Brown of ANSES, during a conference at Space. These characteristics, together with the fact that there is no vaccine, make it difficult to control an established infection.
Un virus hypercontagieux
TCoV was more frequent in farms where there were no other poultry species. It was also favored when manure removal took place after washing, which could produce recontaminating dust, when there was only one disinfection and no lime spreading. The absence of a complete cleaning of the water circuit (base sequence, acid, disinfection) and drinkers in an open system (bell, bucket) would also seem more favorable.
Seropositivity would be higher when the flock is placed in spring or summer, or when there are other health problems (colibacillosis, early mortality). This could suggest the role favoring spreadings and immunosuppression.
“TCoV circulates in turkey farms with or without digestive problems”, concludes Rozenn Souillard. Even if the analysis of the risk factors concerns only seven batches out of fifty, it underlines “the importance of hygiene and the cleaning disinfection procedure to control enteritis in turkeys”.
A specific serological test
For this study, the samples were analyzed by a serological test that does not differentiate between the TCoV and IBV viruses., which had to be supplemented by molecular biology. But since then, a new serological test, specific for TCoV, has been developed by ANSES. It will enable more distinctive detection in the future. TCoV belongs to the Igacovirus subgenus of the coronaviridae family. Infecting birds, it also includes infectious hen bronchitis virus (IBV) and guinea fowl coronavirus (GfCoV).
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