- Windhoek, Khomas, Namibia
<p>The calculations are shown for two sampling schemes and three hypothetical mean sizes of feeding groups. <i>Q<sub>4</sub></i> is the number of excreted collectable scats per prey individual and cheetah... more
<p>The calculations are shown for two sampling schemes and three hypothetical mean sizes of feeding groups. <i>Q<sub>4</sub></i> is the number of excreted collectable scats per prey individual and cheetah (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0038066#pone-0038066-t002" target="_blank">Table 2</a>) and <i>Q<sub>2</sub></i> is feeding group size. For details see text. <sup>a, b, c</sup> see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0038066#pone-0038066-t002" target="_blank">Table 2</a>.</p
Research Interests: Neuroscience, Physiology, Feeding, Ecology, Cheetah, and 6 moreIndividuals, CF, Prey, Scats, Derived, and hypothetical
Cheetahs have unique social and mating systems, as well as hunting techniques. Males are either territory holders defending small territories or floaters roaming in large, overlapping, undefended home ranges. Both spatial tactics are... more
Cheetahs have unique social and mating systems, as well as hunting techniques. Males are either territory holders defending small territories or floaters roaming in large, overlapping, undefended home ranges. Both spatial tactics are adopted by solitary males or coalitions of males. Females are solitary unless accompanied by offspring. They give birth to two to six cubs, which are hidden in a lair for the first 2 months. In ecosystems with other large predator species, cheetahs adopt several predator avoidance behaviors. Nevertheless, cubs can suffer from high mortality by lions and spotted hyenas, and adult cheetahs may lose kills to kleptoparasites. Cheetahs primarily hunt abundant, small to medium sized prey animals using high-speed chases over short distances. They mainly communicate with vocalization and olfaction, often using prominent landmarks for scent marking. Given the increasing human pressure on carnivores, conservation efforts would benefit from behavioral data in human inhabited areas.
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Current tracking technology such as GPS data loggers allows biologists to remotely collect large amounts of movement data for a large variety of species. Extending, and often replacing interpretation based on observation, the analysis of... more
Current tracking technology such as GPS data loggers allows biologists to remotely collect large amounts of movement data for a large variety of species. Extending, and often replacing interpretation based on observation, the analysis of the collected data supports research on animal behaviour, on impact factors such as climate change and human intervention on the globe, as well as on conservation programs. However, this analysis is difficult, due to the nature of the research questions and the complexity of the data sets. It requires both automated analysis, for example, for the detection of behavioural patterns, and human inspection, for example, for interpretation, inclusion of previous knowledge, and for conclusions on future actions and decision making. For this analysis and inspection, the movement data needs to be put into the context of environmental data, which helps to interpret the behaviour. Thus, a major challenge is to design and develop methods and intuitive interface...
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Additional file 1: Table S1. Data table of ELISA and IB results containing information on all samples (species, suborder, site, ELISA, IB and final results for T. gondii, N. caninum and B. besnoiti, respectively).
Namibia is thought to host the largest population of free-ranging cheetahs Acinonyx jubatus and the majority of this po-pulation inhabits commercial farm-land (Morsbach 1987). Some farmers consider that cheetahs prey on both livestock and... more
Namibia is thought to host the largest population of free-ranging cheetahs Acinonyx jubatus and the majority of this po-pulation inhabits commercial farm-land (Morsbach 1987). Some farmers consider that cheetahs prey on both livestock and wild herbivores that are valuable for trophy hunting, and this perceived offtake has generated conflict leading to the indiscrimina-te elimination of cheetahs from some farms (Marker et al. 1996). To help assess the economic cost of cheetahs on commercial farmland, informati-on on the proportion of different prey species in their diet is required. As it is difficult to directly assess the diet of farmland cheetahs due to their extremely shy behaviour and the small chance of finding fresh prey carcasses (Fig. 1.), we assessed the diet of chee-tahs on Namibian farmland by applying a simple method originally devised for police forensic science. The method is based on the unique imprint of hair from different prey species in cheetah faeces (e.g. Keogh ...
doi: 10.3389/fmicb.2014.00526 Oligotyping reveals differences between gut microbiomes of free-ranging sympatric Namibian carnivores (Acinonyx
Life history theory predicts that mothers should provide their offspring with a privileged upbringing if this enhances their offspring ’ s and their own fitness. In many mammals, highranking mothers provide their offspring with a... more
Life history theory predicts that mothers should provide their offspring with a privileged upbringing if this enhances their offspring ’ s and their own fitness. In many mammals, highranking mothers provide their offspring with a privileged upbringing. Whether dispersing sons gain fitness benefits during adulthood from such privileges (a ‘ silver spoon ’ effect) has rarely been examined. In this paper, we show that in the complex, female-dominated society of spotted hyaenas, high-born sons grew at higher rates, were more likely to disperse to clans offering the best fitness prospects, started reproducing earlier and had a higher reproductive value than did lower-born sons. This illustrates the evolutionary importance of maternal effects even in societies in which male size or fighting ability does not influence fitness. By demonstrating for the first time in a non-human mammal that maternal status influences immigration patterns, the study also advances our understanding of two key ...
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Recent advances in tracking technology allow biologists to collect large amounts of movement data for a variety of species. Analysis of the collected data supports research on animal behaviour, influence of impact factors such as climate... more
Recent advances in tracking technology allow biologists to collect large amounts of movement data for a variety of species. Analysis of the collected data supports research on animal behaviour, influence of impact factors such as climate change and human intervention, as well as conservation programs. Analysis of the movement data is difficult, due to the nature of the research questions and the complexity of the data sets. It requires both automated analysis, e.g. for the detection of behavioural patterns, and human inspection, e.g. for interpretation, inclusion of previous knowledge, and for conclusions on future actions and decision making. We present a concept and implementation for the visual analysis of cheetah movement data in a web-based fashion that allows usage both in the field and in office environments.
corticosteroid concentrations in Serengeti females were significantly higher than in Ngorongoro females. Energy expenditure by lactation is exceptionally high in spotted hyenas and this may be reflected in their corticosteroid levels. The... more
corticosteroid concentrations in Serengeti females were significantly higher than in Ngorongoro females. Energy expenditure by lactation is exceptionally high in spotted hyenas and this may be reflected in their corticosteroid levels. The faecal corticosteroid levels in both populations were higher in lactating than in non-lactating females. During periods of social stability, faecal corticosteroid concentrations increased in non-lactating females but not in lactating females as social status declined. Lactating Serengeti females had significantly higher faecal corticosteroid concentrations during periods with acute severe social stress than during periods without, indicating that the HPA axis is sensitive to social stimuli even in lactating females. So far few studies have used non-invasive monitoring methods for assessing social stress in freeranging animals. This study demonstrates for the first time, to the authors' knowledge, that corticosteroid concentrations may differ be...
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Namibia is thought to host the largest population of freeranging cheetahs Acinonyx jubatus and the majority of this population inhabits commercial farmland (Morsbach 1987). Some farmers consider that cheetahs prey on both livestock and... more
Namibia is thought to host the largest population of freeranging cheetahs Acinonyx jubatus and the majority of this population inhabits commercial farmland (Morsbach 1987). Some farmers consider that cheetahs prey on both livestock and wild herbivores that are valuable for trophy hunting, and this perceived offtake has generated conflict leading to the indiscriminate elimination of cheetahs from some farms (Marker et al. 1996). To help assess the economic cost of cheetahs on commercial farmland, information on the proportion of different prey species in their diet is required.
Background Improved knowledge on vector-borne pathogens in wildlife will help determine their effect on host species at the population and individual level and whether these are affected by anthropogenic factors such as global climate... more
Background Improved knowledge on vector-borne pathogens in wildlife will help determine their effect on host species at the population and individual level and whether these are affected by anthropogenic factors such as global climate change and landscape changes. Here, samples from brown hyenas (Parahyaena brunnea) from Namibia (BHNA) and spotted hyenas (Crocuta crocuta) from Namibia (SHNA) and Tanzania (SHTZ) were screened for vector-borne pathogens to assess the frequency and genetic diversity of pathogens and the effect of ecological conditions and host taxonomy on this diversity. Methods Tissue samples from BHNA (n = 17), SHNA (n = 19) and SHTZ (n = 25) were analysed by PCRs targeting Anaplasmataceae, Rickettsia spp., piroplasms, specifically Babesia lengau-like piroplasms, Hepatozoidae and filarioids. After sequencing, maximum-likelihood phylogenetic analyses were conducted. Results The relative frequency of Anaplasmataceae was significantly higher in BHNA (82.4%) and SHNA (10...
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Noninvasive techniques hold many potential advantages including limiting capture and handling stress in wild animals. Scat (feces) samples provide a geophysical landmark and are a biological source for a range of biomedical and ecological... more
Noninvasive techniques hold many potential advantages including limiting capture and handling stress in wild animals. Scat (feces) samples provide a geophysical landmark and are a biological source for a range of biomedical and ecological questions. The cheetah’s low densities lead to difficulties to study them in the wild, including challenges to find scat samples. Use of professionally trained scat-detection dogs can substantially increase the effectiveness of scat searches. Species, individual identity, and sex of the individual can be determined from scat samples using molecular genetic techniques. Once the information about the individual has been obtained, follow-up questions can be asked. For instance diet composition can be determined using prey species hair found in the scat, and endocrine analyses can provide information about the health and physiology at an individual or population level. Because of their noninvasiveness, these techniques can also be used for long-term mo...
Considerable research has been conducted on cheetah ecology. Cheetahs can exist in a wide variety of habitats from thick scrub to open grassland, and habitat selection is based on a variety of factors, including visibility, prey density,... more
Considerable research has been conducted on cheetah ecology. Cheetahs can exist in a wide variety of habitats from thick scrub to open grassland, and habitat selection is based on a variety of factors, including visibility, prey density, and avoidance of competitively superior predators. Cheetahs naturally occur at low densities and require a prey base of small to medium-sized ungulates that can be consumed rapidly, minimizing the risks for cheetahs of being detected by larger carnivores that can usurp their kills. Cheetahs exhibit wide ranging movements and large home ranges—over 2000 km 2 in some areas. Reported densities generally range from 0.3 to 3.0 adult cheetahs per 100 km 2 . The species distribution, density, and activity patterns are impacted by human activities and the presence of larger carnivores. Understanding cheetah habitat requirements and movement ecology, especially pertaining to long-distance movements, will become progressively more important as the cheetah’s range becomes increasingly fragmented.
Human–wildlife conflicts occur worldwide. Although many nonlethal mitigation solutions are available, they rarely use the behavioral ecology of the conflict species to derive effective and long-lasting solutions. Here, we use a long-term... more
Human–wildlife conflicts occur worldwide. Although many nonlethal mitigation solutions are available, they rarely use the behavioral ecology of the conflict species to derive effective and long-lasting solutions. Here, we use a long-term study with 106 GPS-collared free-ranging cheetahs (Acinonyx jubatus) to demonstrate how new insights into the socio-spatial organization of this species provide the key for such a solution. GPS-collared territory holders marked and defended communication hubs (CHs) in the core area of their territories. The CHs/territories were distributed in a regular pattern across the landscape such that they were not contiguous with each other but separated by a surrounding matrix. They were kept in this way by successive territory holders, thus maintaining this overdispersed distribution. The CHs were also visited by nonterritorial cheetah males and females for information exchange, thus forming hotspots of cheetah activity and presence. We hypothesized that th...
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Behavioural studies of elusive wildlife species are challenging but important when they are threatened and involved in human-wildlife conflicts. Accelerometers (ACCs) and supervised machine learning algorithms (MLAs) are valuable tools to... more
Behavioural studies of elusive wildlife species are challenging but important when they are threatened and involved in human-wildlife conflicts. Accelerometers (ACCs) and supervised machine learning algorithms (MLAs) are valuable tools to remotely determine behaviours. Here we used five captive cheetahs in Namibia to test the applicability of ACC data in identifying six behaviours by using six MLAs on data we ground-truthed by direct observations. We included two ensemble learning approaches and a probability threshold to improve prediction accuracy. We used the model to then identify the behaviours in four free-ranging cheetah males. Feeding behaviours identified by the model and matched with corresponding GPS clusters were verified with previously identified kill sites in the field. The MLAs and the two ensemble learning approaches in the captive cheetahs achieved precision (recall) ranging from 80.1% to 100.0% (87.3% to 99.2%) for resting, walking and trotting/running behaviour, ...
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Background Knowledge about parasitic infections is crucial information for animal health, particularly of free-ranging species that might come into contact with livestock and humans. Methods We investigated the seroprevalence of three... more
Background Knowledge about parasitic infections is crucial information for animal health, particularly of free-ranging species that might come into contact with livestock and humans. Methods We investigated the seroprevalence of three tissue-cyst-forming apicomplexan parasites (Toxoplasma gondii, Neospora caninum and Besnoitia besnoiti) in 506 individuals of 12 wildlife species in Namibia using in-house enzyme linked immunosorbent assays (indirect ELISAs applying purified antigens) for screening and immunoblots as confirmatory tests. We included six species of the suborder Feliformia, four species of the suborder Caniformia and two species of the suborder Ruminantia. For the two species for which we had most samples and life-history information, i.e. cheetahs (Acinonyx jubatus, n = 250) and leopards (Panthera pardus, n = 58), we investigated T. gondii seroprevalence in relation to age class, sex, sociality (solitary, mother-offspring group, independent sibling group, coalition group...
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Population estimates are a fundamental requirement of ecology and conservation. While capture-recapture models are an established method for producing such estimates, their assumption of homogeneous capture probabilities is problematic... more
Population estimates are a fundamental requirement of ecology and conservation. While capture-recapture models are an established method for producing such estimates, their assumption of homogeneous capture probabilities is problematic given that heterogeneity in individual capture probability is inherent to most species. Such variation must be accounted for by abundance models; otherwise, biased estimates are risked.Here, we investigate the performance of four types of heterogeneity models for estimating abundance of male cheetah , a species with two distinct spatial tactics of territorial and nonterritorial (floater) males. The differences in spatial movements of territory holders and floaters are expected to result in intrasexual heterogeneous capture probabilities. Four heterogeneity models were used to model male abundance at five territories in central Namibia; (a) a spatial tactic model, (b) a finite mixture model, both run in program MARK, (c) a floater-only model, and (d) a...
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Physiological stress markers may provide valuable insight for our understanding of costs of given life-history strategies or of wildlife health condition, most importantly in case of threatened species. In the last decade, there has been... more
Physiological stress markers may provide valuable insight for our understanding of costs of given life-history strategies or of wildlife health condition, most importantly in case of threatened species. In the last decade, there has been growing interest in the ecological relevance of cellular oxidative stress, which would provide complimentary information to that obtained by the classic analyses of glucocorticoid hormones. In this study, we analysed the sex and species variation of five blood-based markers of oxidative status, both molecular oxidative damage and antioxidant protection, in sympatric cheetahs (Acinonyx jubatus) and leopards (Panthera pardus) living on Namibian farmlands. Both these terrestrial carnivores are classified as vulnerable by the International Union for Conservation of Nature. We found that female cheetahs had significantly higher serum reactive oxygen metabolites of non-protein origin and lower glutathione peroxidase activity in whole blood than both male and female leopards and male cheetahs. We also found that cheetahs and leopards differed in the association between the two antioxidant enzymes glutathione peroxidase and superoxide dismutase. Correlations among oxidative status markers were stronger in female cheetahs than leopards or male cheetahs. Our results suggest that female cheetahs are more sensitive to local sources of stress. Our work did not corroborate the assumption that two species with different life histories consistently differ in key physiological traits.
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Identifying how dominance within and between the sexes is established is pivotal to understanding sexual selection and sexual conflict. In many species, members of one sex dominate those of the other in one-on-one interactions. Whether... more
Identifying how dominance within and between the sexes is established is pivotal to understanding sexual selection and sexual conflict. In many species, members of one sex dominate those of the other in one-on-one interactions. Whether this results from a disparity in intrinsic attributes, such as strength and aggressiveness, or in extrinsic factors, such as social support, is currently unknown. We assessed the effects of both mechanisms on dominance in the spotted hyaena (Crocuta crocuta), a species where sexual size dimorphism is low and females often dominate males. We found that individuals with greater potential social support dominated one-on-one interactions in all social contexts, irrespective of their body mass and sex. Female dominance emerged from a disparity in social support in favour of females. This disparity was a direct consequence of male-biased dispersal and the disruptive effect of dispersal on social bonds. Accordingly, the degree of female dominance varied with the demographic and kin structure of the social groups, ranging from male and female co-dominance to complete female dominance. Our study shows that social support can drive sex-biased dominance and provides empirical evidence that a sex-role-defining trait can emerge without the direct effect of sex.Females are often dominant in spotted hyaena societies. Here, the authors show that this dominance emerges from male-biased dispersal and its effect on social bonds, which can result in increased social support for females.
Assessing the numbers and distribution of threatened species is a central challenge in conservation, often made difficult because the species of concern are rare and elusive. For some predators, this may be compounded by their being... more
Assessing the numbers and distribution of threatened species is a central challenge in conservation, often made difficult because the species of concern are rare and elusive. For some predators, this may be compounded by their being sparsely distributed over large areas. Such is the case with the cheetah The IUCN Red List process solicits comments, is democratic, transparent, widely-used, and has recently assessed the species. Here, we present additional methods to that process and provide quantitative approaches that may afford greater detail and a benchmark against which to compare future assessments. The cheetah poses challenges, but also affords unique opportunities. It is photogenic, allowing the compilation of thousands of crowd-sourced data. It is also persecuted for killing livestock, enabling estimation of local population densities from the numbers persecuted. Documented instances of persecution in areas with known human and livestock density mean that these data can provi...
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ABSTRACT Carnivore conservationists agree that addressing the socioeconomic needs of people is critical to human-carnivore conflict mitigation. We therefore welcome studies that encompass complex social and cultural factors that affect... more
ABSTRACT Carnivore conservationists agree that addressing the socioeconomic needs of people is critical to human-carnivore conflict mitigation. We therefore welcome studies that encompass complex social and cultural factors that affect the severity of human-carnivore conflict on Namibian farmlands. However, we contend that the recent study by Rust et al. (2016) was poorly designed, used inappropriate sampling methods, lacked quantitative information on their qualitative results, and ultimately produced unsupported conclusions about the role of historic apartheid and current racism in exacerbating human-carnivore conflict in Namibia. We outline our concerns regarding the methods used, and demonstrate that the conclusions drawn by Rust et al. were not supported by their data.
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Although the significance of the gut microbiome for host health is well acknowledged, the impact of host traits and environmental factors on the interindividual variation of gut microbiomes of wildlife species is not well understood. Such... more
Although the significance of the gut microbiome for host health is well acknowledged, the impact of host traits and environmental factors on the interindividual variation of gut microbiomes of wildlife species is not well understood. Such information is essential; however, as changes in the composition of these microbial communities beyond the natural range might cause dysbiosis leading to increased susceptibility to infections. We examined the potential influence of sex, age, genetic relatedness, spatial tactics and the environment on the natural range of the gut microbiome diversity in free-ranging Namibian cheetahs (Acinonyx jubatus). We further explored the impact of an altered diet and frequent contact with roaming dogs and cats on the occurrence of potential bacterial pathogens by comparing free-ranging and captive individuals living under the same climatic conditions. Abundance patterns of particular bacterial genera differed between the sexes, and bacterial diversity and richness were higher in older (&gt;3.5 years) than in younger individuals. In contrast, male spatial tactics, which probably influence host exposure to environmental bacteria, had no discernible effect on the gut microbiome. The profound resemblance of the gut microbiome of kin in contrast to nonkin suggests a predominant role of genetics in shaping bacterial community characteristics and functional similarities. We also detected various Operational Taxonomic Units (OTUs) assigned to potential pathogenic bacteria known to cause diseases in humans and wildlife species, such as Helicobacter spp., and Clostridium perfringens. Captive individuals did not differ in their microbial alpha diversity but exhibited higher abundances of OTUs related to potential pathogenic bacteria and shifts in disease-associated functional pathways. Our study emphasizes the need to integrate ecological, genetic and pathogenic aspects to improve our comprehension of the main drivers of natural variation and shifts in gut microbial communities possibly affecting host health. This knowledge is essential for in situ and ex situ conservation management.
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Cheetahs (Acinonyx jubatus) are highly specialised large felids, currently listed as vulnerable on the IUCN red data list. In captivity, they are known to suffer from a range of chronic non-infectious diseases. Although low heterozygosity... more
Cheetahs (Acinonyx jubatus) are highly specialised large felids, currently listed as vulnerable on the IUCN red data list. In captivity, they are known to suffer from a range of chronic non-infectious diseases. Although low heterozygosity and the stress of captivity have been suggested as possible causal factors, recent studies have started to focus on the contribution of potential dietary factors in the pathogenesis of these diseases. Fatty acids are an important component of the diet, not only providing a source of metabolisable energy, but serving other important functions in hormone production, cellular signalling as well as providing structural components in biological membranes. To develop a better understanding of lipid metabolism in cheetahs, we compared the total serum fatty acid profiles of 35 captive cheetahs to those of 43 free-ranging individuals in Namibia using gas chromatography-mass spectrometry. The unsaturated fatty acid concentrations differed most remarkably bet...
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A 3.5-year-old wild born cheetah (Acinonyx jubatus), living in a large enclosure on a private Namibian farm, developed a large exophytic nodular neoplasm in its skin at the height of the left shoulder blade. We describe the clinical... more
A 3.5-year-old wild born cheetah (Acinonyx jubatus), living in a large enclosure on a private Namibian farm, developed a large exophytic nodular neoplasm in its skin at the height of the left shoulder blade. We describe the clinical appearance, the surgical removal, and histological examination of the tumor, which was diagnosed as a moderately pigmented benign basal cell tumor. A three-year follow-up showed no evidence of recurrence after the surgery. Although neoplasia is reported in nondomestic felids, only very few concern cheetahs. So far, no case of basal cell tumor was described in this species.
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Determining the immunological phenotype of endangered and threatened populations is important to identify those vulnerable to novel pathogens. Among mammals, members of the order Carnivora are particularly threatened by diseases. We... more
Determining the immunological phenotype of endangered and threatened populations is important to identify those vulnerable to novel pathogens. Among mammals, members of the order Carnivora are particularly threatened by diseases. We therefore examined the constitutive innate immune system, the first line of protection against invading microbes, of six free-ranging carnivore species; the black-backed jackal (Canis mesomelas), the brown hyena (Hyena brunnea), the caracal (Caracal caracal), the cheetah (Acinonyx jubatus), the leopard (Panthera pardus) and the lion (Panthera leo) using a bacterial killing assay. The differences in immune responses amongst the six species were independent of their foraging behaviour, body mass or social organisation but reflected their phylogenetic relatedness. The bacterial killing capacity of black-backed jackals, a member of the suborder Caniformia, followed the pattern established for a wide variety of vertebrates. In contrast, the five representativ...
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The cheetah population in Namibia is the largest free-ranging population in the world and a key population for research on the health status of this species. We used serological methods and quantitative real-time PCR to test free-ranging... more
The cheetah population in Namibia is the largest free-ranging population in the world and a key population for research on the health status of this species. We used serological methods and quantitative real-time PCR to test free-ranging and captive Namibian cheetahs for the presence of feline leukemia virus (FeLV), a gammaretrovirus that can be highly aggressive in populations with low genetic diversity such as the cheetah. We also assessed the presence of antibodies to other gammaretroviruses, and the response to a FeLV vaccine developed for domestic cats. Up to 19% of the free-ranging cheetahs, 27% of the captive non-vaccinated cheetahs and 86% of the captive vaccinated cheetahs tested positive for FeLV antibodies. FeLV-antibody positive free-ranging cheetahs also tested positive for Rauscher murine leukemia virus antibodies. Nevertheless, FeLV was not detectable by quantitative real-time PCR and no reverse transcriptase activity was detectable by polymerase-enhanced reverse tran...
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Research Interests: Carnivores and Bacteria
Research Interests: Diet, Multidisciplinary, Animal Husbandry, Humans, Carbon Isotopes, and 12 moreFemale, Animals, Male, Namibia, PLoS one, Nitrogen Isotopes, Cattle, Ecosystem, Swine, Antelopes, Hares, and Food Chain
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Cheetah populations are diminishing rapidly in their natural habitat. One reason for their decline is thought to be a high susceptibility to (infectious) diseases because cheetahs in zoos suffer from high disease-induced mortality. Data... more
Cheetah populations are diminishing rapidly in their natural habitat. One reason for their decline is thought to be a high susceptibility to (infectious) diseases because cheetahs in zoos suffer from high disease-induced mortality. Data on the health status of free-ranging cheetahs are scarce, and little is known about their exposure and susceptibility to infectious diseases. We determined seroprevalences to nine key viruses (feline herpesvirus 1, feline calicivirus, feline parvovirus, feline coronavirus, canine distemper virus, feline immunodeficiency virus [FIV], puma lentivirus, feline leukemia virus, and rabies virus) in 68 free-ranging cheetahs on east-central Namibian farmland, 24 nonvaccinated Namibian captive cheetahs, and several other wild carnivore species and conducted necropsies of cheetahs and other wild carnivores. Eight of 11 other wild carnivores were seropositive for at least one of the viruses, including the first record of an FIV-like infection in a wild felid we...
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Sera from 38 free-ranging spotted hyenas (Crocuta crocuta) in the Serengeti ecosystem, Tanzania, were screened for exposure to coronavirus of antigenic group 1. An immunofluorescence assay indicated high levels of exposure to coronavirus... more
Sera from 38 free-ranging spotted hyenas (Crocuta crocuta) in the Serengeti ecosystem, Tanzania, were screened for exposure to coronavirus of antigenic group 1. An immunofluorescence assay indicated high levels of exposure to coronavirus among ...
Research Interests: Microbiology, Veterinary Microbiology, Nonparametric Statistics, Carnivora, Tanzania, and 15 moreVeterinary, Phylogeny, Sequence alignment, Animals, Feline Infectious Peritonitis, Ecosystem, Feces, Group, Age Factors, Veterinary Sciences, Lymph Node, Clinical Signs, Coronavirus, reverse transcriptase polymerase chain reaction, and Coronavirus infections
Dispersal is a key driver of ecological and evolutionary processes. Despite substantial efforts to explain the evolution of dispersal, we still do not fully understand why individuals of the same sex of a species vary in their propensity... more
Dispersal is a key driver of ecological and evolutionary processes. Despite substantial efforts to explain the evolution of dispersal, we still do not fully understand why individuals of the same sex of a species vary in their propensity to disperse. The dominant hypothesis emphasizes movements and assumes that leaving home (dispersal) and staying at home (philopatry) are two alternative strategies providing different fitness. It suggests that only individuals of high phenotypic quality can pursue the most beneficial strategy; the others are left to do a "best-of-a-bad" job. An alternative hypothesis emphasizes settlement decisions and suggests that all individuals pursue a single strategy of choosing the breeding habitat or group with the highest fitness prospects; choosing the natal group (philopatry) and choosing a nonnatal group (dispersal) are then outcomes of these decisions. We tested both hypotheses using a long-term study of a free-ranging population of a group-li...
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Host defense peptides act on the forefront of innate immunity, thus playing a central role in the survival of animals and plants. Despite vast morphological changes in species through evolutionary history, all animals examined to date... more
Host defense peptides act on the forefront of innate immunity, thus playing a central role in the survival of animals and plants. Despite vast morphological changes in species through evolutionary history, all animals examined to date share common features in their innate immune defense strategies, hereunder expression of host defense peptides (HDPs). Most studies on HDPs have focused on humans, domestic and laboratory animals. More than a thousand different sequences have been identified, yet data on HDPs in wild-living animals are sparse. The biological functions of HDPs include broad-spectrum antimicrobial activity and immunomodulation. Natural selection and coevolutionary host-pathogen arms race theory suggest that the extent and specificity of the microbial load influences the spectrum and potency of HDPs in different species. Individuals of extant species-that have lived for an extended period in evolutionary history amid populations with intact processes of natural selection-...
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Thirteen strains of Streptococcus equi subsp. ruminatorum from free-ranging spotted hyenas (Crocuta crocuta) and plains zebras (Equus burchelli) in Tanzania were characterized by biochemical and molecular-biological methods. Although the... more
Thirteen strains of Streptococcus equi subsp. ruminatorum from free-ranging spotted hyenas (Crocuta crocuta) and plains zebras (Equus burchelli) in Tanzania were characterized by biochemical and molecular-biological methods. Although the colony appearance of the S.e. ruminatorum wildlife strains differed from that of the S.e. ruminatorum type strain CECT 5772(T), all biochemical reactions of the wildlife strains were similar to those of the type strain. In addition, all wildlife strains produced hyaluronidase and were capable of hydrolysing arginine, three strains (23%) synthesized acetoin, but only eight strains (62%) produced acid from ribose. rep-PCR indicated that different clones of S.e. ruminatorum were distributed among the hyena and zebra populations in the study area. Identical rep-PCR patterns in hyena and zebra strains suggest that a direct transmission of S.e. ruminatorum between these species may occur. The presence of a M-like protein (SrM) gene was demonstrated in all...