Fertility Control for Grey Squirrels : what do the next 5 years look like? Giovanna Massei National Wildlife Management Centre APHA RSST, UK Squirrel Accord and Royal Forestry Society Sand Hutton, 19 October 2017
Human-wildlife conflicts are increasing Conflitti uomo-fauna selvatica Damage to crops, forestry, property Disease transmission Impact on native species Road traffic accidents Livestock predation
Methods to mitigate human-wildlife conflicts Lethal methods poisoning shooting trapping exclusion Non-lethal methods behaviour modification fertility control translocation diversionary feeding
Novel immuno-contraceptives Vaccines inducing antibodies against proteins or hormones essential for reproduction single-dose injectable vaccines from our US partners GonaCon Gonadotrophin Releasing Hormone vaccine 75-100% animals infertile for 2-8 years Credible practical applications BUT animals must be captured we need an oral contraceptive
Fertility control applications via injectable vaccine Wild boar: 1 dose GonaCon stopped reproduction in 92% sows for 5-8 years Feral goats: 1 dose GonaCon reduced fertility by 83-92% for > 4 years California ground squirrels: 1 dose GonaCon reduced the % of lactating females by 91% (year 1) and 96% (year 2)
The project Developing and delivering oral contraceptives to control populations of grey squirrels 5 years 1 M 4 research groups: UK x2 France USA
The project Test novel contraceptive formulations (lab rats) Design systems to monitor feeding patterns by squirrels (lab + field) Start breeding colony of squirrels Test contraceptive doses, frequency, bait type (lab rats) Optimise bait uptake by squirrels (field) Test effectiveness of contraceptive in squirrels (lab) Optimise bait uptake by squirrels in different contexts (urban,rural) Liaise with regulatory authorities to assemble registration package Refine model on integrated methods to reduce squirrel numbers Pilot trials with contraceptives on squirrel populations Initiate trials for registration package Year 1 Year 2 Year 3+ 4 Year 5 Text in footer 7
The APHA team Field studies Project leader Lab studies coordinator coordinator 4 field ecologists 2 lab ecologists 1 statistician 2 modellers 2 lab technicians
Oral Biology, immuno-contraceptive behaviour, population vaccine targeting dynamics GnRH APHA and collaborators developed novel GnRH-based oral vaccine 60% rats fed the contraceptive did not breed (control rats: 10-30%) Rats fed the contraceptive in a bait showed reduced response to the vaccine: fewer rats responded and had lower antibodies to the vaccine Novel formulation needed for oral vaccine to increase immune response
Novel formulation to deliver an oral immuno-contraceptive Spores and pollen grains Pollen/spores are natural and renewable Commercially available Genetic material removed to obtain sporopollenin exine capsules (SpECs) SpECs withstand stomach conditions Proven effective delivery of drugs such as fats, oils, vitamins, enzymes, hormones, ibuprofen
SpECs for an oral contraceptive vaccine Proven vaccine delivery in SpECs fed to mice increased antibodies in mice antibody response lasted for up to 7 months SpECs move into mouse gut wall, thus offering : a possible mechanism for oral vaccination potential to maintain this response for at least a few months
Developing Proposed an oral work contraceptive Identify SpECs species Trials with laboratory rats to test SpEC-encapsulated oral vaccine Captive trial repeated on grey squirrels Field pilot trials to confirm efficacy, % of the population treated Large-scale trials to monitor effects at population level
Biology, behaviour, population dynamics Target species delivery For contraceptives that are not target specific Specificity through delivery Grey squirrel specific hopper
Target species delivery Grey squirrel-specific hopper to deliver baits containing oral contraceptives Rhodamine B in whiskers of grey squirrels Text in footer 14
Defra study January-March 2017: aims 1. Model the effort required to reduce grey squirrel population size via culling, contraception or culling + contraception 2. Identify data to collect to improve the ability of the model to predict the impact of population control on squirrels number 15
Defra study January-March 2017: results
Defra study January-March 2017: results Culling with different levels of effort Text in footer 17
Defra study January-March 2017: results Fertility control with different levels of efficacy Text in footer 18
Defra study January-March 2017: results Culling in Year 1, followed by fertility control with different levels of efficacy Text in footer 19
Current and future work Proven GnRH-based contraception Candidate oral contraceptive available Delivery method available Model impact of fertility control on population dynamics Confirm effectiveness of contraceptives Test bait uptake by % of grey squirrels Manage public expectations Captive and field trials Registration of drugs Funding Public support Stakeholder engagement Done In progress To do
Scalable applications for oral contraceptives Oral contraceptives scalable to new species and contexts Non-native invasive species, incl. feral animals Over-abundant wildlife Where culling is illegal, unfeasible, undesirable To complement culling to control populations or their economic / environmental impact
In summary Oral contraceptives will be an important tool to manage wildlife Raising public awareness on feasibility, cost, safety, sustainability of different methods will be key to successful management
With thanks to the squirrel team! Questions? giovanna.massei@apha.gsi.gov.uk