Pathology and Tissue Distribution of Turkey Coronavirus in Experimentally Infected Chicks and Turkey Poults

Abstract

Twenty 1-day-old specific pathogen free chicks and 20 1-day-old commercially derived turkey poults were inoculated with a Brazilian strain of turkey coronavirus (TCoV) to study the pathogenicity and virus distribution up to 14 days post-inoculation by histopathology, immunohistochemistry, reverse transcriptase polymerase chain reaction and sequencing. At 2-14 dpi, TCoV antigens were detected in the paranasal sinus and lachrymal accessory gland (Harderian gland) of infected chicks and in the ileum, ileocaecal junction and caecum of infected poults. Lymphocytic inflammation was present in these tissues. TCoV was re-isolated from pooled tissue suspensions of nasal concha, Harderian gland and paranasal sinus from chicks, as well as from the ileum, ileocaecal junction and caecum of poults, after three consecutive passages in 28-day-old embryonated turkey eggs. Viral RNA corresponding to the spike gene region (1178-2073 genome position) was amplified from the upper respiratory tract of chickens and from the intestinal tract of poults and phylogenetic analysis confirmed the identity as TCoV. This is the first description of TCoV antigens and mRNA in upper respiratory tissues in experimentally infected chickens.

Visual detection of turkey coronavirus RNA in tissues and feces by reverse-transcription loop-mediated isothermal amplification (RT-LAMP) with hydroxynaphthol blue dye

“…All samples were also tested by conventional RT-PCR, as described previously [9]. Each assay was conducted in triplicate.…”

“…Embryo tissues (ileum and ileumecaecal junction portions) were prepared by infecting 25-day-old embryonated turkey eggs with 0.3 ml 10 2.4 EID 50 TCoV via the amniotic sac, as described previously [9,10]. A control group of 20 turkey embryos at the same age were inoculated with sterile phosphate buffered solution (PBS).…”

Isolation and molecular characterization of Brazilian turkey reovirus from immunosuppressed young poults

“…Additionally, poult enteritis complex (PEC) has been associated with enteritis and growth rate reductions in commercial turkeys worldwide [4-6, 13-15, 19-21, 23, 24]. To date, turkey coronavirus (TCoV), turkey astroviruses 1 and 2 (TAstV-1 and TAstV-2), and turkey rotavirus (TRotV) have been described to be circulating among poult breeders in Brazil [3,7,9,18]. In contrast, turkey reovirus (TReoV) had never been detected so far.…”

“…The latter samples were homogenized with a twofold volume of MEM (Sigma-Aldrich Ò , St. Louis, MO, USA), clarified by centrifugation (2,5009g for 20 min), and filtered twice using 0.45-and 0.22-lm syringe filters [9]. The suspensions were propagated in Vero cells for no more than four passages.…”

Desenvolvimento de uma reação em cadeia pela polimerase para a detecção de coronavírus de perus (TCOV), por meio de um fragmento da região S2 de seu genoma

“…(GUY et al, 1997;GUY, 2003), os resultados encontrados neste estudo poderiam ser atribuídos a uma possível contaminação durante a necropsia, seja por ruptura da mucosa intestinal, que se torna mais delgada devido a destruição dos enterócitos (POMEROY et al, 1978;YU et al, 2000) ou por descuido Pesquisando o gene 3, conservado não só em TCoV, mas também em IBV e coronavírus de faisão (CAVANAGH et al, 2001), as cinco (05) (GOODWIN et al, 1995;HOORFAR;COOK, 2003). Para tanto, seria necessário replicar esse material em ovo embrionado (CAVANAGH et al, 2002, ISMAIL;TANG;GOMES et al, 2010;JACKWOOD et al, 2010), por 3-4 passagens, ou mais, até que os embriões mostrem lesões como aumento de tamanho do intestino (YU et al, 2000), a fim de aumentar a concentração desse vírus, se ele estiver ainda viável na amostra. A reação com esse par de iniciadores funcionou, uma vez que o padrão de bandas apresentadas na eletroforese para algumas amostras de campo são idênticas aquelas originadas do controle positivo, proveniente de um vírus TCoV variante (JACKWOOD et al, 2010) e dessa forma, este resultado sugere que esta estirpe viral esteja presente no Brasil.…”