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Can African swine fever be controlled through wild boar management?
• Despite the high mortality rates observed in naïve populations, not all infected animals die after short time. Indeed, both virus and antibodies are detected in affected animals, revealing the survival to infection of some individuals (Kurinov et al. 2012; Diagnosis of Lithuanian wild boar, 2014).
African swine fever
Remember the facts
Expanding; high reproductive rate; low mortality
Contact with pigs through
sex & food
Movements up to 250 km, increased by hunting
Fences, rivers & highways are no barriers
Remember the facts
Aims of this presentation
• Review wild boar management tools • Hunting • Capturing • Counting
• Discuss intervention options regarding ASF • Biosafety • Population control • Other options
5
Aims of this presentation
• Review wild boar management tools • Hunting • Capturing • Counting
• Discuss intervention options regarding ASF • Biosafety • Population control • Other options
6
Hunting wild boar
Picture source: boarmasters.com
Several hunters
With or without dogs
Hunting site might be pre-baited
One hunter
Without dogs
Hunting site must be pre-baited
One hunter
With or without dogs
Key sites might be pre-baited
REMEMBER: •Hunting success (& fun) depends on wild boar abundance (i.e.
hunters will not happily reduce their game) •Baiting improves hunting success, but increases wild boar survival
and reproduction
Driven hunt Stand hunt Stalking
Trapping wild boar
Capture specificity (wild boar) was 96.3% Capture effort was 16.5 days per wild boar Low pre-release mortality during capture and handling (6.5%) associated with trauma in corral traps Post-release monitoring by GPS-devices revealed no mortality due to anaesthesia
Trapping wild boar
ASFORCE: Wild boar life-trapping in Sardinia, last week
Trapping wild boar
REMEMBER: • Trapping depends on baiting and can be counter-productive • However, trapping is needed for tagging and research1
• Few cases of real success in reducing a wild boar population by trapping2
1.- Barasona et al. BMCVM; 2.- Boadella et al. 2012 PREVET
Estimating wild boar abundance
Hunting data as relative abundance indicator
Acevedo et al. 2006 Acta Theriologica
Estimating wild boar abundance
Presencia
P
Ausencia A
A
A A
A A A
Acevedo et al. 2007 Epid & Infect
Wildlife monitoring: populations & diseases
EU FP7 EMIDA ERA-NET
Aims of this presentation
• Review wild boar management tools • Hunting • Capturing • Counting
• Discuss intervention options regarding ASF • Biosafety • Population control • Other options
14
Barriers-biosafety
Culling
Habitat management
Boadella et al. 2011 EJWR
From disease discovery to disease control
+ +
Closed (biosafe) farm
Open air farm Free-range
V V
V
+ + Control de traslados
Barreras
Acceso a agua y comederos
Eliminación no selectiva
Eliminación selectiva
V V
V
Vacunación del ganado
V V V V V
Vacunación del reservorio
Higiene
+
+
+
Integrated control options for shared diseases
Biosecurity 2: Fences and barriers
Owens & Owens 1980 Afr. Wildlife, Sutmoller 2002 Ann. NY Acad. Sci., Jori 2011 PreVet, Schneider 2012 J.S. Afr. Vet. Assoc.
Vulnerable to elephants, suids…
Interfere with natural movements and migration
Biosecurity 2: Fences and barriers
Biosecurity 3: Carcasses and hunting remains
Good! Wrong! Source: J. Vicente, IREC.
Wildlife population control
Population control 1: Random culling EXAMPLES WHERE RANDOM CULLING FAILED •Red fox culling – rabies •Wild boar culling – Aujeszky’s disease •Wild boar culling – CSF
Artois et al. 2011 Rev. Sci. Tech. OIE; Boadella et al. 2012 PreVet
“Culling reservoir populations to control the transmission of pathogens has proven disappointingly inefficient”
M. Artois
“Culling could become a part of integrated
control strategies (…) contributing to increase their success likelihood,
or reducing the total expenses”
M. Boadella
Guidelines for ASF prevention through the control of wild boar populations
MONITORING WILD BOAR & ASF 1.Current wild boar population monitoring in Europe is not enough. Efforts are needed towards the establishment of
appropriate population monitoring tools. These tools cannot rely only on hunting results, since some populations are not hunted.
2.The surveillance of infectious agents including ASF should also be improved. Disease monitoring should consider both hunter-harvest sampling and non-invasive techniques such as oral fluid collection.
BIOSAFETY 3.Contacts of wild boar with domestic pigs should be avoided enhancing the biosecurity and infrastructures of the pig
holdings from the infected area (small scale fencing). Larger barriers to wild boar movements are unlikely to succeed and have undesirable consequences (large scale fencing).
4.Wild boar access to domestic pig/wild boar carcasses should be avoided. National carcass management schemes should be considered within the risk factors and as intervention options.
5.Wild boar translocations should be thoroughly monitored to avoid introduction at long distances. Illegal short- and long-distance wild boar translocations are known, but not their frequency.
POPULATION CONTROL 6.Intense hunting (>50% of the estimated population) can reduce wild boar numbers locally, particularly in closed
populations, but such an intense hunting pressure is difficult to maintain. In evenly distributed populations, reduction can be achieved in the long term if feeding is banned and the hunting pressure increased.
7.Hunting is a useful population management tool. However, two aspects need urgent European regulation from the animal health point of view: (1) the proper disposal of hunting offal/remains and (2) game baiting and feeding.
8.Future wild boar population control should consider control professionals and new methods, possibly including contraception.
22
Research needs
23
1. Basic parameters of ASFV maintenance within and between
wild boar groups should be studied in selected ASF-affected wild boar populations to estimate basic parameters for transmission rate modelling.
2. Tools to control wild boar without hunting, for instance in protected areas and urban areas, are needed. Options to consider include refinements of trapping and contraception.
3. Ongoing control efforts (e.g. increased hunting pressure) offer an extraordinary opportunity to critically assess the success of current intervention.
Management & Research Needs • Monitor POPULATIONS and DISEASES (remember:
“nothing permanent, except change”) • Set limits to OVERABUNDANCE and AGGREGATION
– Regulate feeding – Increase hunting pressure
• Proper disposal of HUNTING REMAINS • Set up and test innovative CONTROL tools
