Cancer is a common diagnosis in many mammalian species, yet they vary in their vulnerability to cancer. The factors driving this variation are unknown, but life history theory offers potential explanations to why cancer defense mechanisms are not equal across species. Here we report the prevalence of neoplasia and malignancy in 37 mammalian species, representing 11 mammalian orders, using 42 years of well curated necropsy data from the San Diego Zoo and San Diego Zoo Safari Park. We collected data on life history components of these species and tested for associations between life history traits and both neoplasia and malignancy, while controlling for phylogenetic history. These results support Peto’s paradox, in that we find no association between lifespan and/or body mass and the prevalence of neoplasia or malignancy. However, a positive relationship exists between litter size and prevalence of malignancy (p=0.005, Adj. R2=0.212), suggesting that a species’ life history strategy may influence cancer vulnerabilities. Lastly, we tested for the relationship between placental invasiveness and malignancy. We find no evidence for an association between placental depth and malignancy prevalence (p=0.618, Adj. R2=0.068). These findings provide insight into the relationship between life history traits and cancer vulnerabilities, which suggest a trade-off between reproduction and cancer defenses. Lay Summary Comparative oncology

ABSTRACT:Mycoplasmas are an important cause of upper respiratory tract disease (URTD) in desert tortoises (Gopherus agassizii) and have been a main focus in attempts to mitigate diseasebased population declines. Infection risk can vary with an animal's population of origin, making screening tests popular tools for determining infection status in individuals and populations. To provide additional methods for investigating URTD we developed quantitative PCR (qPCR) assays specific for agents causing clinical signs of URTD: Mycoplasma agassizii, Mycoplasma testudineum, and Testudinid herpesvirus 2 (TeHV2) and tested necropsied desert tortoises housed at the Desert Tortoise Conservation Center in Las Vegas, Nevada, USA, as well as wild desert tortoises (n53), during 2010. Findings were compared with M. agassizii enzyme-linked immunosorbent assay (ELISA) data. Based on qPCR, the prevalence of M. agassizii was 75% (33/44) and the prevalence of TeHV2 was 48% (20/42) in the evaluated population. Both agents were also present in the wild tortoises. Mycoplasma testudineum was not detected. The M. agassizii ELISA and qPCR results did not always agree. More tortoises were positive for M. agassizii by nasal mucosa testing than by nasal flush. Our findings suggest that mycoplasmas are not the only agents of concern and that a single M. agassizii ELISA or nasal flush qPCR alone failed to identify all potentially infected animals in a population. Caution should be exercised in using these tests for disposition decisions.

Abstract. The objective of the current study was to identify factors associated with avian mycobacteriosis in zoo birds. Inventory data, population health records, and necropsy data from eligible birds in the Zoological Society of San Diego's (ZSSD) collection from 1991-2005 (n 5 13,976) were used to describe disease incidence, prevalence, and postmortem findings. A matched case-control study was then conducted to identify factors describing demographic, temporal, and enclosure characteristics, along with move and exposure histories. Cases (disease-positive birds; n 5 167) were matched in a 1:7 ratio with controls (diseasenegative birds; n 5 1169) of similar age and taxonomic grouping. Potential risk factors were evaluated using univariate and multivariable conditional logistic regression. Disease prevalence and incidence were estimated for the study period at 1.2% and 3 cases/(1,000 bird-years at risk), respectively. Lesion characteristics and order prevalence are described. In the multivariable model, case birds were more likely to have been previously housed with a bird with mycobacterial disease involving the intestinal tract (odds ratio [OR] 5 5.6, P , 0.01) or involving only nonintestinal sites (OR 5 2.0, P , 0.01). Cases were more likely to have been imported into the collection than hatched at the ZSSD (OR 5 4.2, P , 0.01). Cases were moved among ZSSD enclosures more than controls (OR 5 1.1 for each additional move, P , 0.01). Findings will help guide future management of this disease for zoo bird populations.

MethodsMycobacteria isolated from more than 100 birds diagnosed with avian mycobacteriosis at the San Diego Zoo and its Safari Park were cultured postmortem and had their whole genomes sequenced. Computational workflows were developed and applied to identify the mycobacterial species in each DNA sample, to find single-nucleotide polymorphisms (SNPs) between samples of the same species, to further differentiate SNPs between as many as three different genotypes within a single sample, and to identify which samples are closely clustered genomically.ResultsNine species of mycobacteria were found in 123 samples from 105 birds. The most common species were Mycobacterium avium and Mycobacterium genavense, which were in 49 and 48 birds, respectively. Most birds contained only a single mycobacterial species, but two birds contained a mixture of two species. The M. avium samples represent diverse strains of M. avium avium and M. avium hominissuis, with many pairs of samples differing by hundreds or thousands of SNPs across their common genome. By contrast, the M. genavense samples are much closer genomically; samples from 46 of 48 birds differ from each other by less than 110 SNPs. Some birds contained two, three, or even four genotypes of the same bacterial species. Such infections were found in 4 of 49 birds (8%) with M. avium and in 11 of 48 birds (23%) with M. genavense. Most were mixed infections, in which the bird was infected by multiple mycobacterial strains, but three infections with two genotypes differing by ≤ 10 SNPs were likely the result of within-host evolution. The samples from 31 birds with M. avium can be grouped into nine clusters within which any sample is ≤ 12 SNPs from at least one other sample in the cluster. Similarly, the samples from 40 birds with M. genavense can be grouped into ten such clusters. Information about these genomic clusters is being used in an ongoing, companion study of mycobacterial transmission to help inform management of bird collections.

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We examined factors that may independently or synergistically contribute to amphibian population declines. We used epidemiologic case-control methodology to sample and analyze a large database developed and maintained by the Arizona Game and Fish Department that describes historical and currently known ranid frog localities in Arizona, U.S.A. Sites with historical documentation of target ranid species (n= 324) were evaluated to identify locations where frogs had disappeared during the study period (case sites) and locations where frog populations persisted (control sites). Between 1986 and 2003, 117 (36%) of the 324 sites became case sites, of which 105 were used in the analyses. An equal number of control sites were sampled to control for the effects of time. Risk factors, or predictor variables, were defined from environmental data summarized during site surveys and geographic information system data layers. We evaluated risk factors with univariate and multifactorial logistic-regression analyses to derive odds ratios (OR). Odds for local population disappearance were significantly related to 4 factors in the multifactorial model. Disappearance of frog populations increased with increasing elevation (OR = 2.7 for every 500 m, p < 0.01). Sites where disappearances occurred were 4.3 times more likely to have other nearby sites that also experienced disappearances (OR = 4.3, p < 0.01), whereas the odds of disappearance were 6.7 times less (OR = 0.15, p < 0.01) when there was a source population nearby. Sites with disappearances were 2.6 times more likely to have introduced crayfish than were control sites (OR = 2.6, p= 0.04). The identification of factors associated with frog disappearances increases understanding of declines occurring in natural populations and aids in conservation efforts to reestablish and protect native ranids by identifying and prioritizing implicated threats.

Cases of tuberculosis (TB) resulting from infection with Mycobacterium tuberculosis complex (MTBC) have been recorded in captive white ( Ceratotherium simum ) and black ( Diceros bicornis ) rhinoceros. More recently, cases have been documented in free-ranging populations of both species in bovine tuberculosis (bTB) endemic areas of South Africa. There is limited information on risk factors and transmission patterns for MTBC infections in African rhinoceros, however, extrapolation from literature on MTBC infections in other species and multi-host systems provides a foundation for understanding TB epidemiology in rhinoceros species. Current diagnostic tests include blood-based immunoassays but distinguishing between subclinical and active infections remains challenging due to the lack of diagnostic techniques. In other species, demographic risk factors for MTBC infection include sex and age, where males and adults are generally at higher risk than females and younger individuals. Limited available historical information reflects similar age- and sex-associated patterns for TB in captive black and white rhinoceros, with more reports of MTBC-associated disease in black rhinoceros than in white rhinoceros. The degree of MTBC exposure in susceptible wildlife depends on their level of interaction, either directly with other infected individuals or indirectly through MTBC contaminated environments, which is dependent on the presence and abundance of infected reservoir hosts and the amount of MTBC shed in their excreta. Captive African rhinoceros have shown evidence of MTBC shedding, and although infection levels are low in free-ranging rhinoceros, there is a risk for intraspecies transmission. Free-ranging rhinoceros in bTB endemic areas may be exposed to MTBC from other infected host species, such as the African buffalo ( Syncerus caffer ) and greater kudu ( Tragelaphus strepsiceros ), through shared environmental niches, and resource co-utilization. This review describes current knowledge and information gaps regarding the epidemiology of TB in African rhinoceros.

The identification of feline herpesvirus (FHV) infected cheetahs (Acinonyx jubatus) and characterization of shedding episodes is difficult due to nonspecific clinical signs and limitations of diagnostic tests. The goals of this study were to develop a case definition for clinical FHV and describe the distribution of signs. Medical records from six different zoologic institutions were reviewed to identify cheetahs with diagnostic test results confirming FHV. Published literature, expert opinion, and results of a multiple correspondence analysis (MCA) were used to develop a clinical case definition based on 69 episodes in FHV laboratory confirmed (LC) cheetahs. Four groups of signs were identified in the MCA: general ocular signs, serious ocular lesions, respiratory disease, and cutaneous lesions. Ocular disease occurred with respiratory signs alone, with skin lesions alone, and with both respiratory signs and skin lesions. Groups that did not occur together were respiratory signs and skin lesions. The resulting case definition included 1) LC cheetahs; and 2) clinically compatible (CC) cheetahs that exhibited a minimum of 7 day's duration of the clinical sign groupings identified in the MCA or the presence of corneal ulcers or keratitis that occurred alone or in concert with other ocular signs and skin lesions. Exclusion criteria were applied. Application of the case definition to the study population identified an additional 78 clinical episodes, which represented 58 CC cheetahs. In total, 28.8% (93/322) of the population was identified as LC or CC. The distribution of identified clinical signs was similar across LC and CC cheetahs. Corneal ulcers and/or keratitis, and skin lesions were more frequently reported in severe episodes; in mild episodes, there were significantly more cheetahs with ocular-only or respiratory-only disease. Our results provide a better understanding of the clinical presentation of FHV, while presenting a standardized case definition that can both contribute to earlier diagnoses and be used for population-level studies.