September 29, 2014
Thailand: Study shows PRRS control should focus on breeding sows
Studying the incidences of porcine reproductive and respiratory syndrome (PRRS) in different districts, scientists concluded that breeding sows should be the focus of targeted surveillance and control.
They were however unable to identify the highly pathogenic form of the virus (HP-PRRS), which is thought to be circulating in the country.
The spatial epidemiology of PRRS in the country was investigated by Weerapong Thanapongtharm of the Department of Livestock Development in Bangkok and other scientists in Thailand and Belgium.
Their study aimed to provide a first description of the spatio-temporal pattern of PRRS in Thailandand to quantify the statistical relationship between the presence of PRRS at the sub-district level and a set of risk factors. This should provide a basis for improving disease surveillance and control of PRRS in Thailand.
Spatial scan statistics were used to detect outbreak clusters and allowed the identification of six spatial clusters covering 15 provinces in Thailand.
Two modelling approaches were used to relate the presence or absence of PRRS outbreaks at the sub-district level to demographic characteristics of swine farming and other epidemiological spatial variables – autologistic multiple regressions and boosted regression trees (BRT). The variables showing a statistically significant association with PRRS presence in the autologistic multiple regression model were the sub-district human population and number of farms with breeding sows.
The predictive capability of the model, as measured by the area under the curve (AUC) of the receiver operating characteristics (ROC) plots was moderate.
Thanapongtharm and co-authors concluded that farms with breeding sows may be an important group for targeted surveillance and control. However, they said that findings obtained at the sub-district level should be complemented by farm-level epidemiological investigations in order to obtain a more comprehensive view of the factors affecting PRRS presence.