Short Term Safety, Immunogenicity, and Reproductive Effects of Combined Vaccination With Anti-GnRH (Gonacon) and Rabies Vaccines in Female Feral Cats

Abstract

Overpopulation of free-roaming cats is a major problem leading to negative impacts on animal health and welfare, public nuisance, transmission of zoonotic diseases, and well-documented harm to wildlife. Surgical sterilization had failed to provide a practical solution to free-roaming cats' overpopulation under field conditions; therefore, efficient and safe non-surgical immunocontraception methods are aspired. Rabies is a deadly virus that may infect people and animals. However, the safety and efficacy of combined vaccination with anti-GnRH and rabies vaccines in feral cats, which often suffer from disrupted health conditions and experienced high stress level, has never been studied. Therefore, our objective was to examine the short-term safety and efficacy of anti-GnRH vaccine (Gonacon), in combination with rabies vaccine in female feral cats. Mature feral female cats were captured and divided into the following groups: (I) GonaconX1-Rabies: queens vaccinated with both Gonacon and rabies (n = 5); (II) GonaconX2-Rabies: queens vaccinated twice with Gonacon (3 weeks apart) and with Rabies (n = 4); (III) OVx-Rabies: queens ovariohysterectomized and vaccinated with rabies (n = 4); (IV) Intact-Rabies: queens vaccinated against rabies and remained intact (n = 3). Comprehensive veterinary examinations and blood tests were performed every 2 weeks for 14 weeks. Data were analyzed by Repeated-Measures-ANOVA or Fisher-Exact-Test. There were neither systemic nor local adverse reactions at the vaccination sites. Blood count (PCV, TS, RBC, HGB, HCT, WBC) and chemistry (Total protein, Total globulin, Albumin, Urea, Creatinine, Creatine kinase, Bilirubin, GGT, ALT, AST) analyses revealed no differences among groups. There were no differences in serum rabies antibodies titers among groups, and queens kept a protective titer (>0.5 IU/mL) starting at 2–4 weeks after vaccination. Anti-GnRH antibodies were detected in all Gonacon-vaccinated queens, excluding one queen (GonaconX2-Rabies group). Anti-müllerian hormone serum concentrations reduced significantly after ovariohysterectomy, as well as gradually following vaccination with Gonacon, but it remained high in intact queens. Evaluation of vaginal cytology and ovarian histology suggested that reproductive cyclicity was suppressed in Gonacon-vaccinated queens. Our results support the conclusion that in the short term, the combined vaccination with Gonacon and rabies is safe and effective in female feral cats. However, further long-term studies are warranted to test this immunologic regimen in feral cats.

WSAVAguidelines for the control of reproduction in dogs and cats

“…Behavioural conditions have multiple causes, and they are rarely, if ever, caused by gonadectomy only. The decision by owners to gonadectomise male dogs in particular is strongly influenced by the erroneous perceived expectation of improvement or prevention of unwanted aggression (offending biting towards dogs and defensive bites towards humans) after surgery (Da Costa et al, 2022;Downes et al, 2015;Notari et al, 2020). Also, despite evidence to the contrary, there is a commonly held erroneous notion that there is a consistent association between levels of serum testosterone concentrations and aggressive behaviour of all types in dogs (Garde et al, 2016).…”

“…All female cats vaccinated with a GnRH vaccine in combination with a rabies vaccine (n=5) had a significant reduction in anti‐Müllerian hormone serum concentrations and evaluation of vaginal cytology and ovarian histology suggested that reproductive cyclicity was suppressed (Novak et al., 2021). Female cats immunised with a GnRH vaccine (n=15; 0.5 mL IM once) were introduced to fertile male cats 4 months after vaccination (Levy et al., 2011).…”

The Role of Veterinarians in Managing Community Cats: A Contextualized, Comprehensive Approach for Biodiversity, Public Health, and Animal Welfare

“…However, community cats may be at risk of contracting the disease if they come into contact with infected animals and are not vaccinated. Hence, it is crucial to implement community cat management programs in developed countries that include rabies vaccination for these animals [43,44].…”

Métodos contraceptivos en gatas: pasado, presente y futuro

“…Como efectos colaterales pudieron advertir la formación de masas en el lugar de la aplicación; no obstante, estas no fueron dolorosas ni ocasionaron dificultad para deambular. Además, la administración de GonaCon™ junto con la vacuna antirrábica resulta efectiva y segura a corto plazo (Novak et al, 2021).…”