ASF in Africa: pathways to prevention and control


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Presented by Armanda D.S. Bastos at the Closing workshop of the BecA‐ILRI‐CSIRO‐AusAID project on Understanding ASF epidemiology as a basis for control, Nairobi, Kenya, 2‐3 October 2013

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ASF in Africa: pathways to prevention and control

  1. 1. Analysis of African Swine Fever epidemiology and pig value chains to underpin design of an ASF risk management strategy on the Kenya-Uganda border Closing workshop of the BecA-ILRI-CSIRO-AusAID project (2011-13): Understanding ASF epidemiology as a basis for control 2nd-3rd October, 2013. Sarova PanAfric Hotel, Nairobi, Kenya Invited presentation: Armanda D.S. Bastos, University of Pretoria Armanda D S Bastos University of Pretoria ASF in Africa: pathways to prevention & control
  2. 2. ASF IN AFRICA PATHWAYS TO PREVENTION & CONTROL Armanda D.S. Bastos, University of Pretoria
  3. 3. Going back in order to go forward In order to effectively prevent and control ASF, we need to understand maintenance and spread of the virus EPIDEMIOLOGY Past Present Future
  4. 4. Current understanding of ASF epidemiology
  5. 5. History        Pigs (Kenya - Montgomery, 1923)  warthog-domestic pig (SA - Steyn 1928, Pi (K th d ti i 1932) Angola (1933)  indigenous/wild-domestic/exotic pig, recognised as same d disease agent (1943) Ornithodoros tick (European incursion 1957, 1960) Sánchez Botija 1963 African Ornithodoros tick (Plowright et al 1969)  sylvatic cycle al. Large-scale surveys of ticks, warthogs & pigs in Africa  domestic pig-tick cycle (Malawi) West Africa W Af i (1978) 1959, 1982, 1985, 1996  d domestic pig cycle i i l European incursion - pig-pig (eradicated) pig pig - pig-tick (threat of re-emergence)  Boinas et al. 2011 Psuedo / actual sylvatic cycle (eradication unlikely)
  6. 6. The latest incursion      Genotype VIII i t d d t G t introduced to Georgia in 2007 (Rowlands et al. 2008) Spread throughout the S d h h h Caucasus region (2007-10) Introduced to Russia (2011) & poses a threat to Europe & China (pig population exceeds 1 billion) – Callaway 2012 Detected in Iran (Rahimi et al. 2010) Has increased its distributional range in Africa (Msinzo et al. 2012) )
  7. 7. ASF distribution in Africa Genotype I, 1959-present Genotype II Genotype II, 1998-2007 Genotype II, 1998 Genotype II, 2007
  8. 8. Resurgence of ASF outbreaks in Africa Pig populations are increasing in Africa  increase in risk of ASF Outbreaks in Cameroon in 1982 Preceded by doubling of pig population Three-fold increase in pig numbers 1980-2010 (FAOSTAT, 2011) True numbers likely underestimated Local slaughter (not recorded) Contribution of pig production to food security & income generation is underestimated
  9. 9. Pig farming systems vary - associated ASF risks vary g g y y y Traditional (free-range during day, confined at night)  increased ASF risk Semi-intensive (generally confined) & intensive (pigs are confined) with biosecurity  reduced risk of ASF and other diseases (Fasina et al. 2012)
  10. 10. Successful eradication - Mauritius      Biosecurity Modified stamping out  soft loans p g Closure of abattoirs Movement control of pigs and pig products M t t l f i d i d t Compliance & legislation (to confine pigs)
  11. 11. Three discrete virus cycles
  12. 12. 1. Tick-warthog-pig cycle Tick warthog pig   Prevention: S P i Separation of sylvatic ( f (tick and warthog) and domestic hosts  control zones Control: Slaughter out policy Success requires: •Buy-in of all stakeholders Buy in •A structured, intensive pig industry •Accurate demarcation of the zones •Flexibility: continuous monitoring and adjustment of zones ones
  13. 13. ASF distribution in Africa Genotype I, 1959-present Genotype II Genotype II, 1998-2007 Genotype II, 1998 Genotype II, 2007
  14. 14. Lessons from Nigeria      First report of disease in 1973 f 9 3 ‘Re-introduction’ in the mid 1990s Molecular characterisation of viruses collected between 1998 and 2006 recover a monophyletic lineage (single introduction) and six CVR variants, of which one is identical to a virus isolated in 1997 in Benin.  prolonged circulation of the virus  uncontrolled movement of infected pigs (within country and across borders)
  15. 15. Molecular epidemiology of ASF in Nigeria Mozambique/60 Nigeria (Tet-36) 99/93 Nigeria (Tet-27) Nigeria (Tet-20) Nigeria (Tet-21) Portugal/60 (Tet-25a) 95/97 Portugal/88 (Tet-25c) Nigeria (Tet-27) 73/-- Nigeria (Tet-32) Nigeria (Tet-29) Nigeria (Tet-32) Angola ( g (Tet-14a) ) 77/82 Nigeria (Tet-36) Nigeria (Tet-21) 99/99 Spain/M61 (Tet-25b) Cameroon/82 (Tet-23b) Dominican Republic/79 (Tet-22) Brazil/78 (Tet-19) Spain/Co68 (Tet-26) Malta/78 (Tet-31) --/60 DRC/Kat67 (Tet-23a) Spain/M61 (Tet-25b) Malta/78 (Tet-31) 53/55 --/50 /50 Cape Verde (Tet-17) Spain/Co61 (Tet-28a) (Tet 28a) Portugal/63 (Tet-28b) Nigeria (Tet-29) Spain/Co68 (Tet-26) Brazil/78 (Tet-19) 57/-- Nigeria (Tet-20) Portugal/60 (Tet-25a) Spain Val76 (Tet-25a) Spain/Co61 (Tet-28a) Portugal/88 (Tet-25c) Dominican Republic/79 (Tet-22) Benin97/1 (Tet-36) 58/-- Cameroon/82 (Tet-23b) Cape Verde (Tet-17) Angola (Tet-14a) Belgium/85 (Tet-18) Benin97/3 (Tet-8) Sardinia/90 (Tet-12) Vict/90 (Tet-14b) Spain/Val76 (Tet-25a) Sardinia/90 (Tet-12) Vict/90 (Tet-14b) Belgium/85 (Tet-18) Dominican Republic/79 (22) Mozambique/60 (a) (b) 0.05 0.002 p72 gene phylogeny ( l tid d t t) 72 h l (nucleotide dataset) CVR phylogeny ( i acid d t t) h l (amino id dataset) Benin97/1 (Tet-36)
  16. 16. CVR: Central Variable Region (Tetrameric repeat coding & alignment) g ( p g g ) Nigeria (Tet-20) Nigeria (Tet-21) Nigeria (Tet-27) Nigeria (Tet 29) (Tet-29) Nigeria (Tet-32) Nigeria (Tet-36) Benin97/1(Tet-36) DRC/67 (Tet-23a) (Tet 23a) Cam/82 (Tet-23b) CapeVerde (Tet-17) Angola/70 (Tet-14a) Vict/90 (Tet-14b) (Tet 14b) Benin97/6 (Tet-8) Malta/78 (Tet-31) Spain/Co61 (Tet-28a) Portugal/63 (Tet-28b) Spain/68 (Tet-26) Portugal/60 (Tet-25a) Spain/M61 (Tet-25b) Spain/Val76 (Tet-25a) Portugal/88 (Tet-25c) DomRep/79 (Tet-22) Brazil/78 (Tet-19) Belgium/85 (Tet-18) Sardinia/90 (Tet-12) Mozambique/60 YC---DNCCCC----GDNCCCC--GDN---------------------CKCW YC---DNCCCC----GDNCCCCC-GDN---------------------CKCW YC---DNCCCC----GDNCCCC--GDNCCCC----------GDN----CKCW YC---DNCCCCC---GDNCCCC--GDNCCCCC---------GDN----CKCZ YCCCGDNCCCCCC--GDNCCCCCCGDNCCCC----------GD?------CZ YC---DNCCCC----GDNCCCCC-GDNCCCCCGDNCCCC--GDN----CKCZ YC---DNCCCC----GDNCCCCC-GDNCCCCCGDNCCCC--GDN----CKCZ Y------CCCCCCCC---------------------DNCDVMDNCCCCCCCZ YC---DNCCCC----GDNC--------------------DVMDNCCCCCNCZ YCC--DNC----------------------------DNCDVMDNC---CCCZ YCC--DNC-------------------------------DVMDNC---CCCZ Y----DNCC---------------------------KN-DVMDJ----CKKZ YCCC-DNC-----------------------------------------DCZ YC---DNCCCC----GDNC------DNC--DNCDNCDNCDVMDN----CKCZ YCCC-DNCCCCCCCCGDNC--------------DNCDNCDVM-------KCZ YC YC---DNCCCCCCC-GDNC--------------DNCDNCDVMDN----CKCZ DNCCCCCCC GDNC DNCDNCDVMDN CKCZ YC---DNCCCCC---GDNC--------------DNCDNCDVMDN----CKCZ YC---DNCCCC----GDNC--------------DNCDNCDVMDN----CKCZ YC---DNCCCCCC------------D-C--DNCDNCDNCDVM-------KCZ YC YC---DNCCCC----GDNC--------------DNCDNCDVMDN----CKCZ DNCCCC GDNC DNCDNCDVMDN CKCZ YC---DNCCCC----GDNC--------------DVCDNCDVMDN----CKCZ YC---DNCCCC----GDNC-----------------DNCDNMDN----CKCZ YC---DNCCCC----GDNC--------------------DVMDN----CKCZ YC YC---DNC-------------------------DNCDNCDVMDN----CKCZ DNC DNCDNCDVMDN CKCZ YC---DNCCC-------------------------------MDN----CKCZ YC---DNCCCC----LDN------------------DNDC--DNDCD-HCLZ
  17. 17. Restrict ASF to the sylvatic cycle      Ongoing O i surveillance: di t d at adult O ith d ill directed t d lt Ornithodoros ticks (Arnot et al. 2010). Mkuze Game Reserve, northern KZN  no evidence of Reserve ASF-infected Ornithodoros ticks. Continued inclusion in the ASF control area needs to be re-evaluated. Currently all Ornithodoros infested areas are being sampled in order to redefine the control zone. l di d t d fi th t l Policies and zoning need to be as flexible and adaptable as the virus  adjust control zones AHEAD of adjustments in range.
  18. 18. Challenges & the Future     Different cycles  different viruses? Monitor & predict emergence of “domestic pig p g pg adapted viral lineages” Monitoring Tools: Molecular Biology GIS Risk Biology, GIS, assessment Prevention: P li i & C P ti Policies Compliance li
  19. 19. References Based primarily on Penrith et al. 2013, Virus Research  Arnot et al. 2009, Onderstepoort J Vet Res  Boinas et al. 2011 Pl O B i l 2011, Plos One  Callaway, 2012, Nature  Fasina et al. 2012 al  Jori & Bastos 2009, Eco Health  Misinzo et al. 2012, Emerging Infectious Diseases  Owolodun et al. 2010, Virus Genes