Fertility Control for Grey Squirrels. Giovanna Massei National Wildlife Management Centre Animal & Plant Health Agency

Transcription

1 Fertility Control for Grey Squirrels Giovanna Massei National Wildlife Management Centre Animal & Plant Health Agency UK Squirrel Accord Annual Meeting, 31 January 2017

2 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

3 Methods to mitigate human-wildlife conflicts Lethal methods poisoning shooting trapping exclusion Non-lethal methods behaviour modification fertility control translocation diversionary feeding

4 Contraception targets in reproduction Hypothalamus Brain GnRH Gonadotrophin Releasing Hormone Anterior Pituitary FSH LH Testis testosterone Ovary Spermatozoa Eggs estrogen progesterone

5 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 % animals infertile for 2-8 years Credible practical applications BUT animals must be captured we need an oral contraceptive

6 Oral contraceptive

7 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)

8 An ideal oral contraceptive No side effects on welfare, physiology and behaviour Long-term effectiveness with single/few doses Effective on/deliverable only to target species No effects on food chain (predators, risks to humans) Inexpensive to produce and administer ALSO: deliverable to a large proportion of the population

9 Adult females Grey squirrel population model % infertility and predicted population size Year 10% 30% 50% 60% 70% 90% > 70% infertility in females to eradicate a population in a few years

10 Biology, behaviour, population dynamics Target species delivery For contraceptives that are not target specific Specificity through delivery Grey squirrel specific hopper

11 Oral Biology, immuno-contraceptive behaviour, population vaccine targetting dynamics GnRH National Wildlife Management Centre and US 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 required for oral vaccine to increase immune response

12 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

13 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

14 Fertility Proposed control applications work Identify SpECs species Captive trial on 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

15 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

16 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 target % of grey squirrels Manage public expectations Captive and field trials Registration of drugs Funding Public support Stakeholder engagement Done In progress To do

17 Thank you for listening Questions?