Retrospective Study on Newcastle Disease in Khartoum State, Sudan

Abstract

To evaluate risk factors for infection with Newcastle disease (ND) in poultry in Khartoum state, Sudan, we conducted a matched case-control study in 25 case farms and 25 control farms in the period from May to December 2012. Also a 5 years data records from January 2008 to December 2012 were investigated. A questionnaire to collect farms data was performed. Data were analyzed by the Chi-squire, Mantel Hanszel estimated odds ratio for univariate analysis and multivariate binary logistic regression. Risk factors significantly associated with ND in the univariate analysis were: age (p-value= 0.037), distance to next poultry farm (p-value= 0.001), keeping other birds (p-value = 0.037), cleaning (p-value= 0.001), external employers (p-value = 0.023), previous ND outbreaks (p-value= 0.000 ) , protective clothes (p-value = 0.005), foot disinfection before entry (p-value= 0.000), machinery disinfection (p-value = 0.002), quarantine application (p-value= 0.000), control of affected birds (p-value= 0.010), rodents control (p-value= 0.000), regular vaccination (p-value = 0.000) and number of doses (p-value= 0.002). The multivariate analysis showed that only regular vaccination (ExpB= 20.370, 95%C.I = 1.217-340.850, p-value = 0.036) has significant association with ND. Regarding data collected from the records, from a total of 563 cases ND accounted for 237 (42.1%), from which 170 (50.4%) were layer while 67 (29%) were broiler. In the univariate analysis risk factors that found significantly associated with ND were: month (p-value= .000), production type (p-value = .000) and season (p-value = .0007). However, in the multivariate analysis risk factors found significantly associated with ND were: Month (p-value =.004), July was highly significant (p-value = 0.002, expB = 6.7, 95%C.I = 1.317-34.68). Also production type (layers) was highly significantly associated with ND (p-value= .000, expB = 2.33 , 95% C.I. = 1.597-3426).