![]() Outbreaks were reported more recently in Poland, Lithuania, Latvia and Estonia. ASF was accidentally introduced into the Caucasus in 2007 from where it spread rapidly and widely within the Russian Federation. It was eradicated in all these countries except Sardinia where it remains endemic and poses a continuous risk of re-introduction and spread in Europe. The prevalent genotype in Gulu district is genotype IX. From 1968–1995, ASFV in the p72 genotype I was present in European countries including Malta, Sardinia, Italy, France, Belgium and the Netherlands. The disease first spread outside the African continent to Portugal in 1957. Initially it was reported from countries in East and Southern Africa but has now spread through Central and West Africa, and Indian Ocean islands with Chad becoming the most recent country to be affected. ĪSF has spread and is now established in many sub-Saharan countries since its discovery in Kenya in 1921. Pigs that apparently recover from the disease become virus carriers. The disease is characterised by high fever, loss of appetite, haemorrhages in the skin and internal organs, and death. ASF produces clinical signs that range from peracute, acute, sub-acute and chronic forms depending on the virulence of the strain, intensity of exposure and pig breed. ASFV isolates vary in their virulence, from highly virulent isolates that kill up to 100% of the pigs to moderately or low virulence viruses with mortalities ranging between 30–70%. The disease is caused by African Swine Fever virus (ASFV), a large double-stranded DNA-virus and sole member of the family Asfarviridae. The disease is of high economic importance both globally and in sub-Saharan Africa where demand for animal protein including pork has greatly increased in the last two decades. This is the first estimate of R 0 for ASFV in a free range smallholder pig keeping system in sub-Saharan Africa and highlights the requirement for more efficient application of available disease control measures.Īfrican Swine Fever (ASF) is a highly contagious, lethal and economically devastating haemorrhagic fever of domestic pigs. Higher resolution and temporally better defined data would likely reduce this variation. We hypothesize that the observed variation in the estimates is a consequence of the data used. Since all these values were above one, they predict the observed persistence of the virus in the population. Estimates from the SI-based method were 1.58 for the CF approach, 1.90 for the LRM, and 1.77 for the SI/N proportion. The R 0 estimates from the nearest infectious neighbour and epidemic doubling time methods were 3.24 and 1.63 respectively. For implementation of the SI model, three approaches were used namely curve fitting (CF), a linear regression model (LRM) and the SI/N proportion. Three methods were used, specifically (i) GIS- based identification of the nearest infectious neighbour based on the Euclidean distance between outbreaks, (ii) epidemic doubling time, and (iii) a compartmental susceptible-infectious (SI) model. A total of 211 outbreaks met the criteria for inclusion in the study. The estimation was based on data collected from outbreaks that affected 43 villages (out of the 289 villages with an overall pig population of 26,570) between April 2010 and November 2011. We estimate R 0 for ASF virus in small holder, free-range pig production system in Gulu, Uganda. Insights into the dynamics and scale of virus transmission can be obtained from estimates of the basic reproduction number ( R 0). African swine fever (ASF) is a highly contagious, lethal and economically devastating haemorrhagic disease of domestic pigs.
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