The epidemiology of pig diseases and the emergence of porcine circovirus type 2 in Papua Province, Indonesia

Abstract

Pigs are an important livestock species for the rural community in South East Asia and Pacific, as well as in Papuan community, Indonesia. Despite that importance, the productivity of Papuan piggeries has been very low. Disease and mortality are recognised major constraints for pig production in Papua. The aim of the thesis was to understand the demographics of pig populations, study the epidemiology of pig diseases in Papuan pigs, including the underdiagnosed PCV2 and to propose locally adapted control approaches to reduce the incidence of selected pathogens. Jayawijaya was chosen as the area of the study because almost one fourth of the pig population in the province can be found in that region. The study was conducted in four stages: the first was a survey of the demography of the traditional pig farming to gain insights into details of daily husbandry, disease management and the productivity of Papuan pig farms. The second was two case studies that established the prevalence of the selected pig pathogens in dead and healthy pigs. The selected pathogens were Classical Swine Fever (CSF), Porcine circovirus type 2 (PCV2), Streptococcus suis, Streptococcus zooepidemicus, and five internal parasites i.e. Trichuris suis, strongyle parasites, Strongyloides ransomi, Ascaris suum, and coccidia. The third study was to confirm the presence or absence of PCV2 virus in Jayawijaya using molecular techniques. The final study was aimed at further characterisation of the complete genome of Papuan PCV2 isolates. Finally, a review was conducted to gather information about the ecology and epidemiology of major pig diseases from Papuan studies and other places, in order to excerpt available control measures that may be applicable under current Papuan context. The survey indicated that pig farms in Jayawijaya were of small size. The productivity was low, indicated by small litter size, low annual farrowing frequency and high mortality. Husbandry was of minimal input demonstrated by low housing quality, low feeding input, minimal use of veterinary services and limited awareness of pig diseases and their consequences. CSFV, strongyle parasites, Trichuris suis and PCV2 were among the main pig pathogens identified in Papua. An association of the presence of these pathogens with pig mortality might have occured but the sample selection bias may have confounded the results. PCV2 was identified for the first time in Papua in the current study. Analyses of the PCV2 genomes of some of the isolates showed that two different PCV2 genotypes have been circulating in Papuan pigs. In order to control pig diseases in Papua, the role of local government is vital, as many Papuan farmers have very little understanding of the relevant pig diseases and their controls. We propose that confining pigs should be prerequisite before any other control methods are to be introduced. In confined pigs, vaccination against CSFV and regular administration of anthelminthics may be two important and practical control measures that should be introduced in broader areas across Papua, especially in regions with available veterinary offices.