Prevalence and associated risk factors of necrotic enteritis on broiler farms in the United Kingdom; a cross-sectional survey

Abstract

In order to determine the prevalence and risk factors for necrotic enteritis in broilers, a cross-sectional survey was conducted among 857 farms, rearing broilers for nine UK poultry companies. The main data collection tool was a postal questionnaire directed at farm managers. Additional information on disease occurrence on the farm was collected from veterinary postmortem reports. The response rate to the questionnaire was 75%, ranging from 54% to 90% within companies. During 2001, 32.8% of the respondents indicated that they had observed a case of necrotic enteritis (95% confidence interval, 29.1 to 36.8) in at least one flock. The disease was most often reported during the months October to February. The point prevalence (necrotic enteritis occurrence in the most recently reared flock) reported by farm managers was 12.3% (95% confidence interval, 9.8 to 15.2). Multilevel logistic regression was performed with the poultry company as the random effect, using the occurrence of necrotic enteritis in the farm's most recently reared flock as the dependent variable. Strong associations were found between the outcome variable and the occurrence of wet litter (odds ratio, 2.39; 95% confidence interval, 1.27 to 4.52; P0/0.007) and coccidiosis (odds ratio, 4.68; 95% confidence interval, 1.74 to 12.55; P0/0.002). In addition, the use of ammonia as a disinfectant for coccidial oocysts appeared to be an independent risk factor (odds ratio, 3.44; 95% confidence interval, 1.53 to 7.71; P0/0.003). Finally, the positive association between the use of plasterboard walls in poultry houses and the occurrence of necrotic enteritis might point to an important role of cleaning and disinfection in the epidemiology of this disease (odds ratio, 3.72; 1.38 to 10.00; P 0/0.009).

Progress and problems in vaccination against necrotic enteritis in broiler chickens

“…Therapeutic antibiotics, such as amoxicillin and tylosin, are often used to prevent and control necrotic enteritis (Hermans & Morgan, 2007). The use of antibiotics is no longer considered an optimal strategy for keeping gut health problems under control because of issues related to antibiotic resistance.…”

The effect of commonly used anticoccidials and antibiotics in a subclinical necrotic enteritis model

“…The onset of NE is, however, a multifactorial event in which (sub)clinical coccidiosis is believed to be one of the major predisposing factors. Several field cases have been reported in which coccidiosis preceded or coincided with necrotic enteritis, although clinical coccidiosis will not always result in the development of necrotic enteritis (Long, 1973;Broussard et al, 1986;Droual et al, 1994;Dhillon et al, 2004;Hermans & Morgan, 2007). Combined experimental infection with species of Eimeria and C. perfringens leads to higher intestinal lesion scores, increased intestinal numbers of C. perfringens, increased mortality and reduced weight gain compared to infection with C. perfringens alone (Al-Sheikhly & Al-Saieg, 1980;Shane et al, 1985;Kageyama et al, 1987;Baba et al, 1992;Baba et al, 1997;Williams et al, 2003;Gholamiandehkordi et al, 2007;Park et al, 2008).…”

“…Until recently, necrotic enteritis was effectively controlled by mixing antimicrobial growth promoters (AGPs) in the broiler feed (Prescott et al, 1978;Elwinger et al, 1992;Elwinger et al, 1998 Since the ban, European farmers rely mostly on curative use of antibiotics like amoxicillin and tylosin, to control necrotic enteritis whenever clinical signs become apparent but no reports exist on the efficiency of these antibiotics to stop the development of necrotic enteritis during an outbreak (Casewell et al, 2003;Hermans & Morgan, 2007). However, when these curative antibiotics are used without precaution for the treatment of foodproducing animals, they may contribute to the development of antimicrobial resistance to important human drugs (Giguère, 2006, Schwarz et al, 2006.…”

Recombinant AttenuatedSalmonella entericaSerovar Typhimurium Expressing the Carboxy-Terminal Domain of Alpha Toxin fromClostridium perfringensInduces Protective Responses against Necrotic Enteritis in Chickens

“…Clostridium perfringens-induced necrotic enteritis (NE) causes high mortality, up to 30% in broiler chickens, and is associated with subclinical chronic intestinal mucosal damage that results in reduced growth and productivity (19,21,29,48). It is a widespread disease in broilers and poses a significant economic impact, with an estimated global loss of more than $2 billion per year (21,29).…”

“…Such use of antibiotics in poultry and livestock has been condemned due to concerns about the increased antibiotic resistance of human pathogens (50). On the other hand, in recent times there has been an increase in sporadic outbreaks and widespread subclinical NE that is linked to the withdrawal of AGP (10,19,48). This had been observed ini-tially in Scandinavian countries following the ban on AGP in the early 1990s (16,51).…”