Better lives through livestock
African swine fever Epidemiology and control
in smallholder pig systems: the value of One
Health
Michel Dione, Senior Scientist
Animal and Human Health Program
International Livestock Research Institute, Dakar, Senegal
Danida Fellowship Center course 2021 Sustainable and Safe Livestock
Production from Farm to Fork, oneline webinar, 19 November 2021

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Outline
 Importance of pig keeping and socio-
economic impact of ASF
 ASF transmission cycles and distribution in
Africa
 Pig value chains and ASF
 Options for ASF control and preventing ASF
 Importance of One Health in the control of
ASF

Importance of pig keeping and impacts of ASF

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Importance of pig keeping

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Socio-economic impact of ASF
– High mortality
– Psychological fear that pigs
would die or have died
– Closure of markets
– Failure to restock
– Pigs sold early and at lower sale
prices
– Suboptimal production –income
foregone

Transmission cycles and distribution of ASF in
Africa

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Etiology of ASF (the virus)
• ASF is caused by a large DNA virus, Asfivirus, only known member of
the family Asfarviridae
• Only known DNA arbovirus
• Stable genetically and in terms of pathogenicity over time
• Tolerates a wide range of temperatures and pH
• Can survive for long periods outside the host in a protein environment
(i.e. not in water or soil)

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Etiology of ASF (the virus)
• Immunologically complicated – no vaccines are available at
this time
• Single serotype with 22 known genotypes
• Only affects members of the family Suidae
• Causes disease of domestic (Sus scrofa domesticus) and feral
(Sus scrofa ferus) swine (wild boar)

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ASF symptoms
 High fever 40-42°C.
 Loss of appetite.
 Depression
 Lethargic- sometimes refusal to stand or move.
 Very unsteady when stood up.
 Vomiting and/or diarrhoea with bloody discharge.
 White skinned pigs: extremities (nose, ears, tail and lower legs) become
cyanotic (blue-purple colour).
 Discrete haemorrhages appear in the skin particularly on the ears and flanks.
 Group will huddle together and are usually shivering.
 Abnormal breathing.
 Heavy discharge from eyes and/or nose.
 Comatose state and death within a few days.

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Clinical signs of ASF
Widespread haemorrhages in the skin.
Huddling pigs/fever
Death
In the peracute form of the disease,
death may occur before any clinical
signs appear.

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Global look at ASF in Africa
SENEGAL 1959
CABO VERDE ?1959
GUINEA BISSAU ?1959
COTE D’IVOIRE 1996-7, 2014
GHANA 1999, 2002
BURKINA FASO 2002
TOGO, BENIN 1997
NIGERIA 1977; 1997
CAMEROON 1982
Zambia 1912
S AFRICA 1928
Mauritius 2007-8
MADAGASCAR 1998
KENYA 1921
ETHIOPIA 2013
CRA. 2011
CHAD 2011
Penrith et al. 2020
Sylvatic cycle Domestic cycle
Namibia 1920s
Namibia 1979
Mozambique 1954
Zimbabwe 1970
Angola 1933
Tanzania 1914
Uganda 1983
 First identification
in Kenya in 1921
 Endemic in Africa

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Cycles in which ASF virus is maintained in Africa
Sylvatic cycle between
common warthogs and tick,
Eastern and Southern
Africa (genotypes I–XXII,
XXIV)
Domestic cycle between domestic
pigs and tick for which they are the
preferred host;
Eastern and Southern Africa
(genotypes VIII, XXIV)
Domestic cycle without arthropod vector that
depends on circulation of the virus in pig populations
with high contact that offer a constant supply of
naïve pigs to infect, (genotypes I–X, XII, XIV–XXIV
in the area with the classic sylvatic cycle; genotypes
I or II elsewhere) – West Africa, Central Africa,
East and Southern Africa
Adapted from Penrith et al. 2020

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Etiology of ASF in Europe and elswhere
 Spread outside Africa, two major excursions, from 1957 to 1994, Italian island of
Sardinia remains infected (Genotype I)
 1970s, emerged in Brazil, Cuba and the Caribbean Islands
 1977, reported in Russia in
 1980 to 1984, outbreaks in the Americas
 2007, Caucasus, Russia and E. Europe, ongoing (Genotype II)
 1990s, eradicated outside of Africa, with the exceptions of an isolated outbreak in
Portugal in 1999 and the island of Sardinia where it has remained endemic
 2008, re-emerged in north-western Europe in Belgium in wild boar
 2018, ASFV was reported for the first time in the People's Republic of Chin
 Sept. 2019, spread in neighboring countries of China

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Cycles in which ASF virus is maintained in Europe
Chenais et al. 2018

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The ASF treat to the global economy
 High morbidity and mortality
 Lack of an efficacious vaccine
 Complex makeup of the ASFV
virion and genome
 Complex lifecycle (sylvatic,
domestic, wildboar)
serious threat
to the global
swine industry
and national
economies

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The increasing importance of the domestic pig cycle
Almost all outbreaks in recent
decades and spread in Africa and
beyond due to movement of
infected pigs and pork

Value chain actors pratices

Pig producers
Pig & pork
traders
Consumers
Input
suppliers
Transporters
Pig value chain actors

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Pig movements and trade
Local trade International trade

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Movement and handling of pork
Informal processing
Pork cuts

Options for ASF control

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Options for ASF control
Control of ASF is hindered by multiple factors
 Lack of an effective vaccine
 The broad geographic distribution of wild and feral swine
 Potential arthropod vectors capable of maintaining the virus
 The increasingly globalized nature of animal agriculture
 The status of smallholder farming

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Options for ASF control
 Early detection
 Restriction on livestock movement
 Culling of herds affected by or potentially exposed to the virus
The development of effective countermeasures for ASF will be
essential in combatting current and future epidemics, and the
associated trade restrictions.

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Options for prevention (Biosecurity)
 Do not feed domestic pigs food waste;
 Do not leave food waste exposed for wild swine species to
access. Dispose of food waste properly.
 Do not take pig meat onto farms, or restrict all food (and
consumption of food) to a canteen.
 All staff on farm should be inducted onto a strict programme
of hand and equipment sanitisation before and after contact
with pigs.

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 Follow rules and regulations on disposal of food waste at ferry
ports and airports.
 Provide the means for staff and visitors to thoroughly sanitise
their hands and equipment.
 Ensure that wild boar, warthogs and wild pigs, and materials
potentially contaminated by such wild species do not come
into contact with domestic pigs.
 Check infected regions before import of goods that could
potentially be contaminated.
 Advise and educate people on the risks of bringing back pork
products from infected regions.
Options for prevention (Biosecurity)

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One Health in the fight of ASF

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Tucker et al. 2021
One Health in the fight of ASF

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