No abstract

As the human population continues to grow, habitat for wildlife shrinks, driving fauna either into extinction or into new habitats, which can create new problems.  In Brazil, the Capybara Hydrochoerus hydrochaeris has become a pest by invading urban and agricultural areas.  These mammals quickly multiply owing to abundant food supply and a lack of natural predators, and they can serve as amplifying hosts for Rickettsia rickettsii, the pathogen of potentially life-threatening Brazilian spotted fever.  Species-specific population management strategies that respect public opinion and consider animal welfare are required for the effective mitigation of this tick-borne zoonotic disease.  In order to control Capybara populations it is necessary to take into account their social dynamics, which are centered on polygynous dominant males with hormone-driven secondary sexual characteristics.  To be a viable management tool, a contraceptive strategy targeting these males must preserve their social status to prevent other males from replacing them.  As part of a larger research project on the efficiency of anti-Gonadotropin-releasing hormone (GnRH) vaccine treatment in free-ranging Capybaras, the aim of this study was to observe the impact of this treatment on alpha male and overall social group behavior.  At the end of the 18-month-study, there were no recorded births involving the immunized animals, and alpha male sexual characteristics and group integrity were preserved.  These results encourage the use of this anti-GnRH vaccine as an alternative population control tool in male Capybara.

The occurrence of acute tympany, probable cause and treatment are being discussed for the first time in Hydrochoerus hydrochaeris, commonly known as the capybara. As part of a capybara population control study, adult male and female (n=18), prior to intervention, were physically confined and subsequently chemically immobilized with a ketamine dexmedetomidine (KD) association. Procedures included health exams, biomaterial collection, and ID markings. For surgical events, the animals were maintained under volatile anesthesia with Isoflurane. One animal, during anesthetic recovery, developed tachycardia and tachypnea, with cyanotic mucosa, and a low SPO2. During auscultation and percussion/palpation a taut abdominal wall was recognized. Shortly thereafter, the animal suffered a cardiorespiratory arrest and failed resuscitation. Immediately performed necropsy suggested death by acute respiratory and circulatory failure due to exerted pressure against the diaphragm and compression of major blood vessels, leading to hypoxia and hypovolemic shock, secondary to cecal dilation. Three animals under general anesthesia demonstrated moderate bloating and were treated by trans-abdominal catheterization for cecal decompression, successfully preventing any potential development of severe tympany. Conclusion: During chemical restraint all animals demonstrated bloat of varies degrees, suggesting iatrogenic cause brought about by adverse effects of anesthetic agents. Acute cecal tympany in sedated capybaras must be anticipated and closely monitored to prevent fatal outcome. Trans-abdominal catheterization into the cecum proved effective in treating bloat.

Introduction: Brazilian spotted fever (BSF), a lethal tick-borne Rickettsioses (2000-2018 >600 human deaths) involving synanthropic capybara as host. Methods: We introduced an alternative to mitigate human-capybara conflicts and epidemiologic concerns of BSF. Complex aspects like transmission dynamics, risk areas, host mobility, and birth rate control, were considered to develop a prevention strategy using an anti-GnRH vaccine. Results: The propositioned immunocontraceptive potentially remove and prevent the spread of BSF from endemic areas. Conclusions: We propose the anti-GnRH vaccine as a BSF prevention strategy based on these favorable results.

Os conflitos Humanos-Animais Selvagens são uma realidade crescente e triste no mundo inteiro, tornando o controle populacional da fauna silvestre e animais ferais o maior desafio, principalmente diante do crescimento da população humana e, consequentemente, da diminuição dos habitats naturais dos animais. As atividades humanas e a destruição da natureza, forçam os animais de vida livre a se dirigirem para áreas urbanas e agrícolas, inevitavelmente, causando conflitos, como o risco de zoonoses, acidentes de trânsito, bem como danos às plantações, quando em busca de alimentos, cujo prejuízo chega a milhões de dólares. Durante décadas, a ciência esteve empenhada em esforços extensivos para desenvolver métodos de controle populacional “humano”; e muitas técnicas foram utilizadas, a fim de se realizar um controle populacional destes animais silvestres. Neste artigo será apresentada uma visão geral dos métodos anticoncepcionais aplicados, com demonstrações gráficas simplificadas de suas interações com a fisiologia reprodutiva, bem como relacionando os prós e os contras dos agentes antifertilidade empregados; também serão comparados com um conjunto de características desejadas para as aplicações em fauna a campo, com ênfase em imunocontracepção reversível, concluindo assim, com as razões do porque este conceito torna-se o mais apropriado e promissor para animais silvestres de vida livre.