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. 2015 May 4;10(5):e0125842.
doi: 10.1371/journal.pone.0125842. eCollection 2015.

Estimating the Basic Reproductive Number (R0) for African Swine Fever Virus (ASFV) Transmission between Pig Herds in Uganda

Mike B Barongo  1 , Karl Ståhl  2 , Bernard Bett  3 , Richard P Bishop  3 , Eric M Fèvre  3 , Tony Aliro  4 , Edward Okoth  3 , Charles Masembe  5 , Darryn Knobel  6 , Amos Ssematimba  7
Affiliations

Estimating the Basic Reproductive Number (R0) for African Swine Fever Virus (ASFV) Transmission between Pig Herds in Uganda

Mike B Barongo et al. PLoS One. .

Abstract

African swine fever (ASF) is a highly contagious, lethal and economically devastating haemorrhagic disease of domestic pigs. Insights into the dynamics and scale of virus transmission can be obtained from estimates of the basic reproduction number (R0). We estimate R0 for ASF virus in small holder, free-range pig production system in Gulu, Uganda. 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. A total of 211 outbreaks met the criteria for inclusion in the study. 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. For implementation of the SI model, three approaches were used namely; curve fitting (CF), a linear regression model (LRM) and the SI/N proportion. The R0 estimates from the nearest infectious neighbour and epidemic doubling time methods were 3.24 and 1.63 respectively. 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. Since all these values were above one, they predict the observed persistence of the virus in the population. We hypothesize that the observed variation in the estimates is a consequence of the data used. Higher resolution and temporally better defined data would likely reduce this variation. This is the first estimate of R0 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.

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Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Number of African swine fever infected herds per month in Gulu District, Uganda, April 2010—November 2011.
Fig 2
Fig 2. Distribution of secondary cases of African swine fever per infection source, Gulu District, April 2010—November 2011.
Fig 3
Fig 3. Distribution of bootstrapped number of secondary outbreaks per infection source.
Fig 4
Fig 4. Exponential curve fitted to the data from the first phase (April—November 2010) of the African swine fever outbreaks in Gulu District, Uganda.
See this image and copyright information in PMC

References

    1. FAO (2011) A value chain approach to animal diseases risk management: Technical foundations and practical framework for field application. Available: http://www.fao.org/docrep/014/i2198e/i2198e00.htm.
    1. Thomas LF, de Glanville WA, Cook EA, Fevre EM (2013) The spatial ecology of free-ranging domestic pigs (Sus scrofa) in western Kenya. BMC Vet Res 9. - PMC - PubMed
    1. Dixon L, Costa J V, Escribano JM, Vinuela E, Wilkinson PJ (2000) Family Asfarviridae. In: Van Regenmortel M, Fauquel C, Bishop D, editors. Virus taxonomy, 7th Report of the ICTV. San Diego: Academic Press. pp. 159–165.
    1. OIE (2010) African Swine Fever: 1–4. Available: http://www.levendehave.nl/sites/default/files/bestanden/African_swine_fe....
    1. Sánchez-Vizcaíno JM, Mur L, Gomez-Villamandos JC, Carrasco L (2015) An Update on the Epidemiology and Pathology of African Swine Fever. J Comp Pathol 152: 9–21. 10.1016/j.jcpa.2014.09.003 - DOI - PubMed

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