Use of Virulent Hemorrhagic Enteritis Virus for the Induction of Colibacillosis in Turkeys

Abstract

Three hundred fifty 1-day-old large white turkeys were reared in brooding batteries to 10 days of age, after which they were moved to floor pens on litter. At 7 weeks of age, poults were allotted into four treatment groups as follows: 1) virulent hemorrhagic enteritis virus (HEV) alone (100 turkeys), 2) Escherichia coli alone (100 turkeys), 3) HEV + E. coli (100 turkeys), and 4) negative controls (50 turkeys). HEV was given orally at 7 weeks of age, followed by E. coli challenge in the drinking water 2 days later for 10 consecutive days. All groups were observed daily for mortality, both during and after challenge. Turkeys that died or were moribund were necropsied, and cultures were taken from the liver and bone marrow for bacterial isolation. Total mortality rates were 23% in the HEV + E. coli group, 10% in the HEV-only group, 3% in the E. coli-only group, and 0% in the negative control group. Cumulative mortality values were significantly different from those of the negative controls (P < or = 0.05) for HEV only and the HEV + E. coli group. E. coli was isolated from the liver and bone marrow of almost all turkeys that died.

Effect of infection of turkeys with haemorrhagic enteritis adenovirus isolate on the selected parameters of cellular immunity and the course of colibacillosis

“…These findings are significant because of the low-virulence of the HE virus used in the experiment and that the infections with this virus in the field caused no clinical signs while post-mortem examination revealed only the enlargement and marble-like appearance of the spleen which is typical for the infection with the HE virus. The findings of this study are similar to those of other authors (Sponenberg et al 1985, Newberry et al 1993, van den Hurk et al 1994, Pierson et al 1996.…”

“…This is caused by different virulence factors of APEC, host susceptibility to infection as well as resistance factors (environmental toxins, immunity, nutrition) (Barnes et al 2003). Infections with the haemorrhagic enteritis virus (HEV) are a frequent factor which makes turkeys more susceptible to infections with the APEC and the development of the clinical form of colibacillosis (Newberry et al 1993, van den Hurk et al 1994, Pierson et al 1996. The quoted authors conducted their studies both under laboratory conditions and in the field, on turkeys infected with the HEV of different virulence levels.…”

Caracterização anatomopatológica e bacteriológica em frangos de corte condenados totalmente por colibacilose sob Serviço de Inspeção Federal

“…coli patogênica para aves (APEC), também pode ter origem intestinal, e nessa forma comumente se visualiza hepatite e esplenite fibrinonecróticas, que pode se disseminar para diversos órgãos (Newberry et al 1993. A maioria das aves condenadas por colibacilose apresentaram apenas lesões hepáticas, o que pode sugerir uma origem bacteriana intestinal.…”

The effect of concurrent infections of haemorrhagic enteritis virus or marble spleen disease virus andEimeria meleagrimitisin turkeys

“…This intestinal damage is important because of its involvement with septicaemic colibacillosis. Investigators (Larsen et al, 1985;Newberry et al, 1993) have reported that E. coli septicaemia may be induced by HEV. Previous research has shown that mortality is extremely difficult to induce in turkeys kept in isolators even when using doses of virus that kill birds kept on litter (personal data).…”

“…MSDV is a group II avian adenovirus which is used in turkeys as a vaccine because of its ability to induce immunity to HEV. HEV is also a group II avian adenovirus which can cause a disease characterized by severe enteritis, bloody droppings and death, and can also initiate colibacillosis (Larsen et al, 1985;Newberry et al, 1993). Typically, this disease occurs in poults 4 weeks of age or older (Domermuth and Gross, 1991).…”