Colorado State University, College of Veterinary Medicine and Biomedical Sciences, 11th annual CVMBS research day scientific proceedings

Includes the Pfizer Research Award winner and abstracts only of the oral sessions and posters

The role of visual adaptation in cichlid fish speciation

D. Shane Wright (1) , Ole Seehausen (2), Ton G.G. Groothuis (1), Martine E. Maan (1) (1) University of Groningen; GELIFES; EGDB(2) Department of Fish Ecology & Evolution, EAWAG Centre for Ecology, Evolution and Biogeochemistry, Kastanienbaum AND Institute of Ecology and Evolution, Aquatic Ecology, University of Bern.In less than 15,000 years, Lake Victoria cichlid fishes have radiated into as many as 500 different species. Ecological and sexual sel ection are thought to contribute to this ongoing speciation process, but genetic differentiation remains low. However, recent work in visual pigment genes, opsins, has shown more diversity. Unlike neighboring Lakes Malawi and Tanganyika, Lake Victoria is highly turbid, resulting in a long wavelength shift in the light spectrum with increasing depth, providing an environmental gradient for exploring divergent coevolution in sensory systems and colour signals via sensory drive. Pundamilia pundamila and Pundamilia nyererei are two sympatric species found at rocky islands across southern portions of Lake Victoria, differing in male colouration and the depth they reside. Previous work has shown species differentiation in colour discrimination, corresponding to divergent female preferences for conspecific male colouration. A mechanistic link between colour vision and preference would provide a rapid route to reproductive isolation between divergently adapting populations. This link is tested by experimental manip ulation of colour vision - raising both species and their hybrids under light conditions mimicking shallow and deep habitats. We quantify the expression of retinal opsins and test behaviours important for speciation: mate choice, habitat preference, and fo raging performance

Relation entre comportement spatial et parasitisme chez le chevreuil en milieu anthropisé

Cette thèse étudie les relations entre comportement spatial et parasitisme dans un contexte croissant d'interactions entre faune domestique et sauvage. Nous émettons l'hypothèse que la cohabitation du Chevreuil avec la faune domestique augmente son exposition et son infestation en parasites, ce qui modifie en retour le comportement du Chevreuil. Nos résultats montrent que (i) la cohabitation du Chevreuil avec les activités humaines augmente son exposition à Toxoplasma gondii et son infestation par des nématodes gastro-intestinaux (NGI), mais pas son exposition à Chlamydia abortus, suggérant pour ce parasite un cycle de transmission restreint aux espèces sauvages ; et (ii) que les chevreuils infestés par des NGI se dispersent moins et plus tardivement. Ce travail contribue à une meilleure compréhension de la circulation de parasites entre la faune domestique et sauvage, et souligne l'importance de considérer le comportement spatial des hôtes sauvages dans l'épidémiologie de maladies dont les effets sur la faune sauvage sont encore mal connus.This thesis investigates the relationships between spatial behaviour and parasitism in the context of increasing interactions between wildlife and domestic animals. We hypothesise that the cohabitation of roe deer with domestic fauna increases its exposure and infestation to parasites, which modify in return the behaviour of roe deer. Our results show that (i) the cohabitation of roe deer with human activities increases its exposure to Toxoplasma gondii and its infestation by gastro-intestinal nematodes (GIN), but not its exposures to Chlamydia abortus, which suggest a possible wild cycle of transmission for this last parasite ; and (ii) roe deer infested by GIN disperse less and later. This work contributes to a better understanding of the circulation of parasites between domestic and the wild animals, and highlights the importance of considering the spatial behaviour of wild hosts in the epidemiology of diseases whose effects on wildlife are still poorly understood

National Koala Disease Risk Analysis Report Appendices V1.2

These appendices comprise the methods and literature reviews that underpin the National Koala Disease Risk Analysis Report (KDRA). That document identifies the knowledge base, information gaps, risk assessments and critical control points for koala disease hazards. The national focus of the KDRA provides a clear, evidence-based assessment of koala disease which will be of value in evaluating disease risk at all regional levels and for koalas in all management situations (captive, rehabilitation and free-ranging). The KDRA is a key guiding document for actions to achieve a vision of “sustainable, resilient and healthy populations of koalas, living in positive welfare within healthy ecosystems across their range”

Infections

• Infections with viruses, bacteria, and macroparasites have been identified as strong risk factors for specific cancers. • Overall, about 2 million (16%) of the total of 12.7 million new cancer cases in 2008 are attributable to infections. This fraction varies 10-fold by region; it is lowest in North America, Australia, and New Zealand (≤ 4%) and highest in sub-Saharan Africa (33%). • Helicobacter pylori, hepatitis B and C viruses, and human papillomaviruses are responsible for 1.9 million cancer cases globally, including mainly gastric, liver, and cervical cancer, respectively. • Infection with HIV substantially increases the risk of virusassociated cancers, through immunosuppression. • Application of existing methods for infection prevention, such as vaccination, safe injection practices, and safe sexual behaviour, or antimicrobial and antiparasite treatments could have a major impact on the future burden of cancer worldwide

The ecological context of diseases of public health importance

The prevention and control of infectious disease continues to be a central priority for human public health. Two infectious agents, the bacterium Yersinia pestis and the filarial nematode Onchocerca volvulus have been responsible for significant public health burden in many populations, and challenges remain in the control and prevention of them both. With known environmental and climatic drivers, vector based transmission and in the case of Y. pestis, zoonotic reservoirs, fully characterising the ecological context of both diseases is vital to properly understanding their epidemiology. In the present study, ecological field data is utilised to investigate this, towards improving predictions and designing control strategies. Despite being contrasting infectious agents, the role of spatial scale and resolution are identified to be vital aspects of both investigations. Ultimately, the importance of a holistic approach to infectious disease epidemiology is highlighted across both systems. In humans and some other animals, infection with Yersina pestis causes the disease plague. Although human infections are now limited to the hundreds annually, they disproportionately affect individuals in lower income settings and as such are still of public health concern. A number of wild rodent species tolerant to infection with Y. pestis act as reservoirs for the bacterium, from which it can transmit into less tolerant susceptible populations. To this end, much research has focused on predicting periods of high infection prevalence (epizootic outbreaks) in the reservoir species in order to predict and prevent transmission events into less tolerant populations. One such reservoir species is the great gerbil, Rhombomys opimus, residing across the pre Balkhash desert in Kazakhstan. Y. pestis prevalence in this population is known to be strongly associated with the gerbil population size. The present study aims to resolve current ability to predict the gerbil population. Burrow level environmental properties are identified to be predictors of gerbil presence at, and long term occupancy of burrows. Gerbil occupancy of burrows could not be replicated using standard metapopulation approaches, nor related to the connectivity of the burrow. Atypical strains of Y. pestis lacking the fraction 1 (F1) surface antigen are isolated and found to be common in the gerbil population. This antigen is highly immunogenic and has a role in virulence determinance. However, no significant hetereogeneities in their distribution or associations with epidemiological outputs could be identified. In several African countries with endemic levels of infection with Onchocerca volvulus, an unusually high prevalence of epilepsy has been observed in the population. Here cross sectional data from a population in the Democratic Republic of Congo is used to build a picture of epilepsy prevalence and to explore a possible functional relationship between epilepsy and O. volvulus. The relationship between O. volvulus and epilepsy is strengthened, and spatial and ecological data lead to the suggestion that responsible drivers have local, rather than global relationships with epilepsy