Contraceptive Vaccines for Wildlife: A Review

Abstract

Citation Kirkpatrick JF, Lyda RO, Frank KM. Contraceptive vaccines for wildlife: a review. Am J Reprod Immunol 2011; 66: 40–50 Wildlife, free‐ranging and captive, poses and causes serious population problems not unlike those encountered with human overpopulation. Traditional lethal control programs, however, are not always legal, wise, safe, or publicly acceptable; thus, alternative approaches are necessary. Immunocontraception of free‐ranging wildlife has reached the management level, with success across a large variety of species. Thus far, the immunocontraceptive research and management applications emphasis have been centered on porcine zona pellucida and gonadotropin‐releasing hormone vaccines. Contraceptive success has been achieved in more than 85 different wildlife species, at the level of both the individual animal and the population. At the population management level with free‐ranging species, the primary focus has been on wild horses, urban deer, bison, and African elephants. The challenges in the development and application of vaccine‐based wildlife contraceptives are diverse and include differences in efficacy across species, safety of vaccines during pregnancy, the development of novel delivery systems for wild and wary free‐ranging animals, and the constraints of certain non‐contraceptive effects, such as effects on behavior. Beyond the constraints imposed by the public and a host of regulatory concerns, there exists a real limitation for funding of well‐designed programs that apply this type of fertility control.

Fertility control to mitigate human–wildlife conflicts: a review

“…These differences are partly responsible for the variable results obtained when using a particular ZP vaccine on different species and have been exploited to make ZP-based vaccines more specific (Kitchener et al 2009;Levy 2011). Porcine ZP (PZP) immunocontraceptive vaccines, derived from ZP isolated from pig ovaries, have been effective in many ungulate species, monkeys, seals, bears and marsupials, but not in rodents, cats, dogs and wild pigs (Eade et al 2009;Kitchener et al 2009;Kirkpatrick et al 2009Kirkpatrick et al , 2011 McLaughlin and Aitken 2011; Table 1). However, recently formulated recombinant PZP3 and PZP4 vaccines, delivered in three injectable doses, caused infertility in up to 89% mice, depending on the formulation type (Gupta et al 2013).…”

“…Initial vaccine formulations also used Freund's complete adjuvant (FCA), which raised safety concerns regarding the occurrence of false-positive tuberculosis skin tests in deer treated with vaccines containing FCA, severe injection-site reactions and potential carcinogenicity for consumers of treated animals (Kirkpatrick et al 2011). The development of a novel, safe and effective adjuvant (AdjuVac, National Wildlife Research Center, Fort Collins, CO, USA) combined with PZP-based vaccine succeeded in rendering animals of several species infertile for several years after a single dose (Table 1).…”

“…Adjuvants, which are inorganic or organic chemicals, macromolecules or entire cells of specific killed bacteria, are typically used to amplify the immune response to an antigen. The factors that affect effectiveness, longevity and side effects of immunocontraceptive vaccines include species, gender, age, individual variation in immunocompetence, as well as the active immunogen, formulation, delivery system and dose and type of adjuvant (Miller et al 2008aHolland et al 2009;Kirkpatrick et al 2011;Ransom et al 2011). The most studied immunocontraceptives in wildlife are zona pellucida (ZP) and GnRH vaccines ( Table 1).…”

“…With the exception of the overview by Fagerstone et al (2010) on issues concerning the use of reproductive inhibitors for wildlife in North America, these reviews have focussed on specific groups such as zoo species and companion animals (Asa and Porton 2005;Munson 2006;Purswell and Kolster 2006;Levy 2011;Massei and Miller 2013), on particular compounds such as immunocontraceptives (Cooper and Larsen 2006;Kirkpatrick et al 2011), on selected species such as brushtail possums (Trichosurus vulpecula) (Ji 2009;Cross et al 2011) or on groups of species such as ungulates (Patton et al 2007). Here, we provide a comprehensive, critical overview of fertility control to mitigate human-wildlife conflicts, with the following aims:…”

“…Conversely, fertility control is increasingly advocated as a safe, humane and effective meansEarly fertility-control agents lacked species-specificity, induced only transitory sterility, thus requiring repeated application, or had a limited window between the dose required to achieve sterility and the toxic or lethal dose. Other obstacles included manufacturing costs, concerns that residues might enter the human food chain and welfare issues regarding side effects Kirkpatrick et al 2011).…”