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Reproductive tumors can impact conception, pregnancy, and birth in mammals. These impacts are well documented in humans, while data in other mammals are limited. An urgent need exists to understand the reproductive impact of these lesions in endangered species, because some endangered species have a documented high prevalence of reproductive tumors. This article documents that the prevalence of both benign and malignant neoplasia differs between African and Asian elephants, with Asian elephants more frequently diagnosed and negatively affected by both. The prevalence of these tumors across mammalian species is compared, and impact plus treatment options in human medicine are reviewed to inform decision making in elephants. Evidence suggests that reproductive tumors can negatively impact elephant conservation. Future studies that document reproductive outcomes, including the success of various treatment approaches in elephants with tumors will benefit conservation efforts.
This multi-institutional collaborative study of neoplasia in snakes reviewed medical records of snakes at each facility to determine species prevalence, survival, and methods of treatment. Complete species numbers of snakes were also collected at each facility. In total, 65 species, 133 snakes, and 149 unique neoplasias were included in this study. Affected species, age, sex, and their tumor prevalence, tumor type and location, metastasis, treatment, and survival data are reported. The highest species-specific tumor prevalence was in Common or Northern Watersnakes (Nerodia sipedon) (30.8%, n = 4 of 13), Eastern Diamond-Backed Rattlesnakes (Crotalus adamanteus) (26.3%, n = 5 of 19), and Timber rattlesnakes (Crotalus horridus) (22.7%, n = 5 of 22). Malignant tumors predominated (86.6%, n = 129 of 149) with soft tissue sarcomas being the most common (30.2%, n = 45 of 149). Snakes with malignant neoplasia, metastases, or indeterminate presence of metastases were statistically more likely to die from their neoplasms than snakes having either benign neoplasia or no diagnosed metastases (p < 0.05). Gender, taxonomic family, and species of those evaluated did not significantly affect the outcome of snakes with neoplasia. Only 27.1% (n = 36 of 133) of snakes received a reported form of treatment and, for those treated, surgical excision was the most common treatment modality. There was not a significant difference in outcome based on treatment; however, surgery and chemotherapy were associated with death from a cause other than their tumor.
The Exotic Species Cancer Research Alliance (ESCRA) has been in existence for 5 y. It is an archive of data from zoological, aquarium and academic institutions into one central location. Through partnerships with over 90 zoos and aquariums we have accumulated over 1,300 cases of cancer across non-domestic species. Although the accumulation of data is important and aids in determining prevalence of cancer across a variety of species, ESCRA is also consulting on active medical cases. ESCRA provides prevalence and prognosis (as available), as well as suggestions for therapy and contacts with oncologists. Within the last 6 mo ESCRA was able to aid veterinarians in making clinical treatment decisions on 22 non-domestic species cancer cases including six exotic small mammals, six carnivores, four reptiles, three primates, one fish, one megavertebrate, and one marine mammal. ESCRA has also participated in five collaborative projects that are either in preparation for publication or have been published. These consults and partnerships are key support for clinical veterinarians of non-domestic animals under human care. By using archived data in every consult, ESCRA implements a model of real-time research and clinical medicine directly impacting the health and welfare of our non-domestic patients.
As evidenced by numerous case reports from zoos, neoplasia in felids is common, but most reports are limited to Panthera species in North America or Europe. In order to obtain a wider epidemiologic understanding of neoplasia distribution, necropsy records at seven facilities (USA, Mexico, Colombia, Peru, and Brazil) were evaluated. In contrast to others, this study population (195 cases, 16 species), included many non-Panthera felids. Overall neoplasia prevalence was 28.2% (55/195). Panthera species had a higher prevalence of neoplasia than non-Panthera species (52.5%; vs. 13.0%). Lions (66.7%), jaguars (55.0%), and tigers (31.3%) had the highest species-specific prevalence of neoplasia. Neoplasms in Panthera species were more frequently malignant than in non-Panthera (86.1% vs. 55.6%). The systems most commonly affected were the reproductive, hematolymphoid, and respiratory. The range of management conditions and more varied genetic backgrounds support a robust taxonomic pattern and suggest that the reported propensity for neoplasia in jaguars may have a genetic basis at a taxonomic level higher than species, as lions and tigers also have high prevalence. Given the high prevalence of neoplasia and high likelihood of malignancy, routine medical exams in all nondomestic felids, but Panthera species in particular, should include thorough assessments of any clinical signs of neoplasia
The factors influencing cancer susceptibility and why it varies across species are major open questions in the field of cancer biology. One underexplored source of variation in cancer susceptibility may arise from trade-offs between reproductive competitiveness (e.g. sexually selected traits, earlier reproduction and higher fertility) and cancer defence. We build a model that contrasts the probabilistic onset of cancer with other, extrinsic causes of mortality and use it to predict that intense reproductive competition will lower cancer defences and increase cancer incidence. We explore the trade-off between cancer defences and intraspecific competition across different extrinsic mortality conditions and different levels of trade-off intensity, and find the largest effect of competition on cancer in species where low extrinsic mortality combines with strong trade-offs. In such species, selection to delay cancer and selection to outcompete conspecifics are both strong, and the latter conflicts with the former. We discuss evidence for the assumed trade-off between reproductive competitiveness and cancer susceptibility. Sexually selected traits such as ornaments or large body size require high levels of cell proliferation and appear to be associated with greater cancer susceptibility. Similar associations exist for female traits such as continuous egg-laying in domestic hens and earlier reproductive maturity. Trade-offs between reproduction and cancer defences may be instantiated by a variety of mechanisms, including higher levels of growth factors and hormones, less efficient cell-cycle control and less DNA repair, or simply a larger number of cell divisions (relevant when reproductive success requires large body size or rapid reproductive cycles). These mechanisms can affect intra- and interspecific variation in cancer susceptibility arising from rapid cell proliferation during reproductive maturation, intrasexual competition and reproduction.
A five-year-old male greater hedgehog tenrec (Setifer setosus) presented with an oral mass and osteolysis of the mandible. Histopathology characterised the mass as a squamous cell carcinoma with extension into the alveolar bone. The patient was treated with intralesional bleomycin, clindamycin, meloxicam and enrofloxacin. After seven weeks of treatment, the animal's condition declined. Radiographs indicated progression of the lesions. Due to its worsening clinical condition and poor response to therapy, the animal was humanely euthanased. This is the first description of squamous cell carcinoma in a greater hedgehog tenrec and the first reported use of intralesional bleomycin in this species.
The bushmeat and pet-trade result in unimaginable numbers of primates needing care at in-country sanctuaries.1 Natural social structure was ranked the most important attribute for welfare in chimpanzees under human care,2 but reproduction control is necessary to manage sanctuary populations.3 This study evaluated the reproductive health of sanctuary chimpanzees managed with long-term contraception. Females > 7 yr and consistent full sexual swellings > 6mo were started on oral contraceptives, followed by implant placement at their next exam, and replaced at recommended intervals (Table 1). Eighty-eight chimpanzees (Pan troglodytes verus; 36 males; 52 females; 1-36 yr) underwent preventive medicine evaluation and contraception updates. Mean duration of contraception in females was 7.8 yr (0-15.3 yr). Five unintended pregnancies occurred: due to a lapse in contraception (n = 2), during active 3-yr implants (Zarin®) use (n = 3); the latter possibly suggesting that these implants have a shorter efficacy in some chimpanzees. Two pregnant females were implanted, parturition was normal. Females on progestin implants experienced folliculogenesis and estrus; 58% (31/53) of females showed: follicles (on ultrasound), sexual swellings, sperm on vaginal cytology, and / or mating. Sexual activity is an important part of chimpanzee social life, and long-term progestin contraception does not appear to interfere with this social interaction. Overall, few reproductive lesions were found via ultrasound examination: uterine leiomyomas (n = 3), testicular mineralization (n = 5), epididymal dilation (n = 1, vasectomy); and peri-testicular fluid (n = 8). Progestin implants in females seem to effectively balance social needs, reproductive control and reproductive health in great apes, thereby maintaining positive social welfare.