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1.
Proc Natl Acad Sci U S A ; 117(52): 33325-33333, 2020 12 29.
Artículo en Inglés | MEDLINE | ID: mdl-33288693

RESUMEN

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 the CHs pose an increased predation risk to young calves for cattle farmers in Namibia. In an experimental approach, farmers shifted cattle herds away from the CHs during the calving season. This drastically reduced their calf losses by cheetahs because cheetahs did not follow the herds but instead preyed on naturally occurring local wildlife prey in the CHs. This implies that in the cheetah system, there are "problem areas," the CHs, rather than "problem individuals." The incorporation of the behavioral ecology of conflict species opens promising areas to search for solutions in other conflict species with nonhomogenous space use.


Asunto(s)
Acinonyx/fisiología , Comunicación Animal , Carnivoría/fisiología , Animales , Femenino , Geografía , Humanos , Masculino , Namibia
2.
Neuroimage ; 257: 119307, 2022 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-35577024

RESUMEN

The combination of signals from different sensory modalities can enhance perception and facilitate behavioral responses. While previous research described crossmodal influences in a wide range of tasks, it remains unclear how such influences drive performance enhancements. In particular, the neural mechanisms underlying performance-relevant crossmodal influences, as well as the latency and spatial profile of such influences are not well understood. Here, we examined data from high-density electroencephalography (N = 30) recordings to characterize the oscillatory signatures of crossmodal facilitation of response speed, as manifested in the speeding of visual responses by concurrent task-irrelevant auditory information. Using a data-driven analysis approach, we found that individual gains in response speed correlated with larger beta power difference (13-25 Hz) between the audiovisual and the visual condition, starting within 80 ms after stimulus onset in the secondary visual cortex and in multisensory association areas in the parietal cortex. In addition, we examined data from electrocorticography (ECoG) recordings in four epileptic patients in a comparable paradigm. These ECoG data revealed reduced beta power in audiovisual compared with visual trials in the superior temporal gyrus (STG). Collectively, our data suggest that the crossmodal facilitation of response speed is associated with reduced early beta power in multisensory association and secondary visual areas. The reduced early beta power may reflect an auditory-driven feedback signal to improve visual processing through attentional gating. These findings improve our understanding of the neural mechanisms underlying crossmodal response speed facilitation and highlight the critical role of beta oscillations in mediating behaviorally relevant multisensory processing.


Asunto(s)
Corteza Visual , Percepción Visual , Estimulación Acústica , Atención/fisiología , Percepción Auditiva/fisiología , Electroencefalografía , Humanos , Estimulación Luminosa , Tiempo de Reacción/fisiología , Corteza Visual/fisiología , Percepción Visual/fisiología
3.
Epilepsia ; 63(5): 1238-1252, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35166379

RESUMEN

OBJECTIVE: 18F-Fluorodeoxyglucose positron emission tomography (FDG-PET) is widely used in presurgical assessment in patients with drug-resistant focal epilepsy (DRE) if magnetic resonance imaging (MRI) and scalp electroencephalography (EEG) do not localize the seizure onset zone or are discordant. METHODS: In this multicenter, retrospective observational cohort study, we included consecutive patients with DRE who had undergone FDG-PET as part of their presurgical workup. We assessed the utility of FDG-PET, which was defined as contributing to the decision-making process to refer for resection or intracranial EEG (iEEG) or to conclude surgery was not feasible. RESULTS: We included 951 patients in this study; 479 had temporal lobe epilepsy (TLE), 219 extratemporal epilepsy (ETLE), and 253 epilepsy of uncertain lobar origin. FDG-PET showed a distinct hypometabolism in 62% and was concordant with ictal EEG in 74% in TLE and in 56% in ETLE (p < .001). FDG-PET was useful in presurgical decision-making in 396 patients (47%) and most beneficial in TLE compared to ETLE (58% vs. 44%, p = .001). Overall, FDG-PET contributed to recommending resection in 78 cases (20%) and iEEG in 187 cases (47%); in 131 patients (33%), FDG-PET resulted in a conclusion that resection was not feasible. In TLE, seizure-freedom 1 year after surgery did not differ significantly (p = .48) between patients with negative MRI and EEG-PET concordance (n = 30, 65%) and those with positive MRI and concordant EEG (n = 46, 68%). In ETLE, half of patients with negative MRI and EEG-PET concordance and three quarters with positive MRI and concordant EEG were seizure-free postsurgery (n = 5 vs. n = 6, p = .28). SIGNIFICANCE: This is the largest reported cohort of patients with DRE who received presurgical FDG-PET, showing that FDG-PET is a useful diagnostic tool. MRI-negative and MRI-positive cases with concordant FDG-PET results (with either EEG or MRI) had a comparable outcome after surgery. These findings confirm the significance of FDG-PET in presurgical epilepsy diagnostics.


Asunto(s)
Epilepsia Refractaria , Epilepsias Parciales , Epilepsia del Lóbulo Temporal , Epilepsia , Epilepsia Refractaria/cirugía , Electroencefalografía , Epilepsias Parciales/cirugía , Epilepsia/diagnóstico por imagen , Epilepsia/cirugía , Epilepsia del Lóbulo Temporal/cirugía , Fluorodesoxiglucosa F18 , Humanos , Imagen por Resonancia Magnética , Tomografía de Emisión de Positrones/métodos , Estudios Retrospectivos , Convulsiones
4.
Sensors (Basel) ; 21(16)2021 Aug 11.
Artículo en Inglés | MEDLINE | ID: mdl-34450868

RESUMEN

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, from 74.4% to 81.6% (54.8% and 82.4%) for feeding behaviour and from 0.0% to 97.1% (0.0% and 56.2%) for drinking and grooming behaviour. The model application to the ACC data of the free-ranging cheetahs successfully identified all nine kill sites and 17 of the 18 feeding events of the two brother groups. We demonstrated that our behavioural model reliably detects feeding events of free-ranging cheetahs. This has useful applications for the determination of cheetah kill sites and helping to mitigate human-cheetah conflicts.


Asunto(s)
Acinonyx , Aceleración , Animales , Animales Salvajes , Humanos , Aprendizaje Automático , Masculino , Namibia
5.
Artículo en Inglés | MEDLINE | ID: mdl-30201541

RESUMEN

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.


Asunto(s)
Acinonyx/metabolismo , Felidae/metabolismo , Estrés Oxidativo , Factores Sexuales , Especificidad de la Especie , Animales , Biomarcadores/sangre , Femenino , Masculino
6.
Parasitol Res ; 118(3): 851-859, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30706167

RESUMEN

The cheetah (Acinonyx jubatus Brookes 1828) is classified as "vulnerable" by the International Union for Conservation of Nature (IUCN). Threats to cheetah populations are a decrease of suitable habitats, an increase of conflicts with livestock farmers and potentially pathogens. While there is some information on the viral and bacterial pathogens circulating in cheetah populations, information on gastrointestinal parasites is scarce. Here, we investigate the gastrointestinal parasites in 39 free-ranging cheetahs in east-central Namibia using a coproscopical parasitological method. Most cheetahs (82%) shed eggs from Ancylostoma which comprised the majority of the total eggs in feces. Eggs and oocysts from Toxascaris (21% of cheetahs), Coccidia (13%), Physaloptera (8%), Taeniidae (5%), Dipylidium (3%), and Diphyllobothriidae (3%) were present at a lower prevalence. Parasite richness and Ancylostoma egg load were higher in juveniles and adults compared to cubs, but were not associated with sex. To our knowledge, this is the first study that assessed gastrointestinal parasites in free-ranging cheetahs and is a key starting point for future studies on the effect of parasites in this threatened species.


Asunto(s)
Acinonyx/parasitología , Cestodos/aislamiento & purificación , Coccidios/aislamiento & purificación , Gastroenteritis/epidemiología , Gastroenteritis/parasitología , Nematodos/aislamiento & purificación , Animales , Biodiversidad , Ecosistema , Granjas , Heces/parasitología , Femenino , Masculino , Namibia/epidemiología
7.
Mol Ecol ; 26(20): 5515-5527, 2017 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-28782134

RESUMEN

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 (>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.


Asunto(s)
Acinonyx/microbiología , Bacterias/clasificación , Microbioma Gastrointestinal , Animales , Animales Salvajes/microbiología , Gatos , Perros , Femenino , Masculino , Namibia , ARN Ribosómico 16S/genética
8.
Gen Comp Endocrinol ; 228: 40-47, 2016 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-26828820

RESUMEN

In mammals, the sex hormone testosterone is the major endocrine variable to objectify testicular activity and thus reproductive function in males. Testosterone is involved in the development and function of male reproductive physiology and sex-related behaviour. The development of a reliable androgen enzyme-immunoassay (EIA) to monitor faecal testosterone metabolites (fTM) is a powerful tool to non-invasively assess the gonadal status of males. We validated an epiandrosterone EIA for male cheetahs by performing a testosterone radiometabolism study followed by high-performance liquid chromatography (HPLC) analyses and excluding possible cross-reactivities with androgenic metabolites not derived from testosterone metabolism. The physiological and biological relevance of the epiandrosterone EIA was validated by demonstrating (1) a significant increase in fTM concentrations within one day in response to a testosterone injection, (2) a significant increase in fTM concentrations within one day in response to a gonadotropin-releasing hormone (GnRH) injection, which failed following a placebo injection, and (3) significant differences in fTM concentrations between adult male and adult female cheetahs and between adult and juvenile male cheetahs of a free-ranging population. Finally, we demonstrated stability of fTM concentrations measured in faecal samples exposed to ambient temperatures up to 72h. Our results clearly demonstrate that the epiandrosterone EIA is a reliable non-invasive method to monitor testicular activity in male cheetahs.


Asunto(s)
Acinonyx/metabolismo , Androsterona/análisis , Heces/química , Técnicas para Inmunoenzimas/métodos , Monitoreo Fisiológico/métodos , Testosterona/metabolismo , Animales , Femenino , Hormona Liberadora de Gonadotropina/administración & dosificación , Hormona Liberadora de Gonadotropina/farmacología , Masculino
9.
Int J Parasitol Parasites Wildl ; 21: 134-142, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37206437

RESUMEN

An opportunistic survey for Echinococcus spp. in wild mammals was conducted in seven distinct study areas throughout Namibia, representing all major ecosystems, between 2012 and 2021. In total, 184 individually attributable faeces and 40 intestines were collected from eight species of carnivores, and 300 carcasses or organs of thirteen species of ungulates were examined for Echinococcus cysts. Nested PCR and sequencing of the mitochondrial nad1 gene led to the identification of five species of the Echinococcus granulosus sensu lato complex. Echinococcus canadensis G6/7 was found throughout Namibia at low frequency in lions, cheetahs, African wild dogs, black-backed jackals and oryx antelopes. Echinococcus equinus was present only in northern Namibia, locally at high frequency in lions, black-backed jackals and plains zebras. Echinococcus felidis was found only in one small area in the north-east of Namibia, but with high frequency in lions and warthogs. Echinococcus granulosus sensu stricto was identified only in two African wild dogs in the north-east of Namibia, and Echinococcus ortleppi occurred in central and southern Namibia in black-backed jackals and oryx antelopes. The development of fertile cysts indicated active intermediate host roles of oryx antelopes for E. canadensis and E. ortleppi, of warthogs for E. felidis, and of plains zebras for E. equinus. Our data support earlier hypotheses of exclusive or predominant wildlife life-cycles for E. felidis involving lions and warthogs, and - in Namibia - for E. equinus involving lions and/or black-backed jackals and plains zebras. Our data further support an interlink of wild and domestic transmission for E. ortleppi. A possible involvement of livestock and domestic dogs in transmission of E. canadensis G6/7 and E. granulosus s.s., the two parasite species with highest zoonotic potential, is uncertain for Namibia and needs further investigation.

10.
Mol Biol Evol ; 28(4): 1455-68, 2011 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-21183613

RESUMEN

For more than two decades, the cheetah (Acinonyx jubatus) has been considered a paradigm of disease vulnerability associated with low genetic diversity, particularly at the immune genes of the major histocompatibility complex (MHC). Cheetahs have been used as a classic example in numerous conservation genetics textbooks as well as in many related scientific publications. However, earlier studies used methods with low resolution to quantify MHC diversity and/or small sample sizes. Furthermore, high disease susceptibility was reported only for captive cheetahs, whereas free-ranging cheetahs show no signs of infectious diseases and a good general health status. We examined whether the diversity at MHC class I and class II-DRB loci in 149 Namibian cheetahs was higher than previously reported using single-strand conformation polymorphism analysis, cloning, and sequencing. MHC genes were examined at the genomic and transcriptomic levels. We detected ten MHC class I and four class II-DRB alleles, of which nine MHC class I and all class II-DRB alleles were expressed. Phylogenetic analyses and individual genotypes suggested that the alleles belong to four MHC class I and three class II-DRB putative loci. Evidence of positive selection was detected in both MHC loci. Our study indicated that the low number of MHC class I alleles previously observed in cheetahs was due to a smaller sample size examined. On the other hand, the low number of MHC class II-DRB alleles previously observed in cheetahs was further confirmed. Compared with other mammalian species including felids, cheetahs showed low levels of MHC diversity, but this does not seem to influence the immunocompetence of free-ranging cheetahs in Namibia and contradicts the previous conclusion that the cheetah is a paradigm species of disease vulnerability.


Asunto(s)
Acinonyx/genética , Variación Genética , Genética de Población , Complejo Mayor de Histocompatibilidad/genética , Acinonyx/inmunología , Secuencia de Aminoácidos , Animales , Susceptibilidad a Enfermedades/inmunología , Genes MHC Clase II , Genotipo , Datos de Secuencia Molecular , Alineación de Secuencia
11.
J Anim Ecol ; 81(1): 36-46, 2012 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21631499

RESUMEN

1. The long-term ecological impact of pathogens on group-living, large mammal populations is largely unknown. We evaluated the impact of a pathogenic bacterium, Streptococcus equi ruminatorum, and other key ecological factors on the dynamics of the spotted hyena Crocuta crocuta population in the Ngorongoro Crater, Tanzania. 2. We compared key demographic parameters during two years when external signs of bacterial infection were prevalent ('outbreak') and periods of five years before and after the outbreak when such signs were absent or rare. We also tested for density dependence and calculated the basic reproductive rate R(0) of the bacterium. 3. During the five pre-outbreak years, the mean annual hyena mortality rate was 0.088, and annual population growth was relatively high (13.6%). During the outbreak, mortality increased by 78% to a rate of 0.156, resulting in an annual population decline of 4.3%. After the outbreak, population size increased moderately (5.1%) during the first three post-outbreak years before resuming a growth similar to pre-outbreak levels (13.9%). We found no evidence that these demographic changes were driven by density dependence or other ecological factors. 4. Most hyenas showed signs of infection when prey abundance in their territory was low. During the outbreak, mortality increased among adult males and yearlings, but not among adult females - the socially dominant group members. These results suggest that infection and mortality were modulated by factors linked to low social status and poor nutrition. During the outbreak, we estimated R(0) for the bacterium to be 2.7, indicating relatively fast transmission. 5. Our results suggest that the short-term 'top-down' impact of S. equi ruminatorum during the outbreak was driven by 'bottom-up' effects on nutritionally disadvantaged age-sex classes, whereas the longer-term post-outbreak reduction in population growth was caused by poor survival of juveniles during the outbreak and subsequent poor recruitment of breeding females. These results suggest synergistic effects of 'bottom-up' and 'top-down' processes on host population dynamics.


Asunto(s)
Brotes de Enfermedades/veterinaria , Hyaenidae/microbiología , Infecciones Estreptocócicas/veterinaria , Streptococcus equi/fisiología , Animales , Demografía , Femenino , Hyaenidae/fisiología , Masculino , Estado Nutricional , Densidad de Población , Dinámica Poblacional , Predominio Social , Infecciones Estreptocócicas/epidemiología , Infecciones Estreptocócicas/transmisión , Tanzanía/epidemiología
12.
Life (Basel) ; 12(6)2022 Jun 20.
Artículo en Inglés | MEDLINE | ID: mdl-35743950

RESUMEN

Free-ranging cheetahs (Acinonyx jubatus) are generally healthy, whereas cheetahs under human care, such as those in zoological gardens, suffer from ill-defined infectious and degenerative pathologies. These differences are only partially explained by husbandry management programs because both groups share low genetic diversity. However, mounting evidence suggests that physiological differences between populations in different environments can be tracked down to differences in epigenetic signatures. Here, we identified differentially methylated regions (DMRs) between free-ranging cheetahs and conspecifics in zoological gardens and prospect putative links to pathways relevant to immunity, energy balance and homeostasis. Comparing epigenomic DNA methylation profiles obtained from peripheral blood mononuclear cells (PBMCs) from eight free-ranging female cheetahs from Namibia and seven female cheetahs living in zoological gardens within Europe, we identified DMRs of which 22 were hypermethylated and 23 hypomethylated. Hypermethylated regions in cheetahs under human care were located in the promoter region of a gene involved in host-pathogen interactions (KLC1) and in an intron of a transcription factor relevant for the development of pancreatic ß-cells, liver, and kidney (GLIS3). The most canonical mechanism of DNA methylation in promoter regions is assumed to repress gene transcription. Taken together, this could indicate that hypermethylation at the promoter region of KLC1 is involved in the reduced immunity in cheetahs under human care. This approach can be generalized to characterize DNA methylation profiles in larger cheetah populations under human care with a more granular longitudinal data collection, which, in the future, could be used to monitor the early onset of pathologies, and ultimately translate into the development of biomarkers with prophylactic and/or therapeutic potential.

13.
Science ; 376(6596): 1012-1016, 2022 05 27.
Artículo en Inglés | MEDLINE | ID: mdl-35617403

RESUMEN

The rate of adaptive evolution, the contribution of selection to genetic changes that increase mean fitness, is determined by the additive genetic variance in individual relative fitness. To date, there are few robust estimates of this parameter for natural populations, and it is therefore unclear whether adaptive evolution can play a meaningful role in short-term population dynamics. We developed and applied quantitative genetic methods to long-term datasets from 19 wild bird and mammal populations and found that, while estimates vary between populations, additive genetic variance in relative fitness is often substantial and, on average, twice that of previous estimates. We show that these rates of contemporary adaptive evolution can affect population dynamics and hence that natural selection has the potential to partly mitigate effects of current environmental change.


Asunto(s)
Adaptación Biológica , Animales Salvajes , Evolución Biológica , Aptitud Genética , Adaptación Biológica/genética , Animales , Animales Salvajes/genética , Aves/genética , Conjuntos de Datos como Asunto , Variación Genética , Mamíferos/genética , Dinámica Poblacional , Selección Genética
14.
J Hered ; 102(6): 653-65, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21914667

RESUMEN

The genes of the major histocompatibility complex (MHC) are a key component of the mammalian immune system and have become important molecular markers for fitness-related genetic variation in wildlife populations. Currently, no information about the MHC sequence variation and constitution in African leopards exists. In this study, we isolated and characterized genetic variation at the adaptively most important region of MHC class I and MHC class II-DRB genes in 25 free-ranging African leopards from Namibia and investigated the mechanisms that generate and maintain MHC polymorphism in the species. Using single-stranded conformation polymorphism analysis and direct sequencing, we detected 6 MHC class I and 6 MHC class II-DRB sequences, which likely correspond to at least 3 MHC class I and 3 MHC class II-DRB loci. Amino acid sequence variation in both MHC classes was higher or similar in comparison to other reported felids. We found signatures of positive selection shaping the diversity of MHC class I and MHC class II-DRB loci during the evolutionary history of the species. A comparison of MHC class I and MHC class II-DRB sequences of the leopard to those of other felids revealed a trans-species mode of evolution. In addition, the evolutionary relationships of MHC class II-DRB sequences between African and Asian leopard subspecies are discussed.


Asunto(s)
Adaptación Biológica , Genética de Población/métodos , Cadenas beta de HLA-DR/genética , Antígenos de Histocompatibilidad Clase I/genética , Panthera/genética , África Austral , Alelos , Secuencia de Aminoácidos , Animales , Asia , Evolución Biológica , Femenino , Aptitud Genética , Variación Genética , Cadenas beta de HLA-DR/inmunología , Antígenos de Histocompatibilidad Clase I/inmunología , Masculino , Datos de Secuencia Molecular , Panthera/inmunología , Filogenia , Filogeografía , Polimorfismo Conformacional Retorcido-Simple , Selección Genética , Homología de Secuencia de Aminoácido
15.
Parasit Vectors ; 14(1): 201, 2021 Apr 14.
Artículo en Inglés | MEDLINE | ID: mdl-33853647

RESUMEN

BACKGROUND: Besnoitia darlingi, B. neotomofelis and B. oryctofelisi are closely related coccidian parasites with felids as definitive hosts. These parasites use a variety of animal species as intermediate hosts. North American opossums (Didelphis virginiana), North American southern plains woodrats (Neotoma micropus) and South American domestic rabbits (Oryctolagus cuniculus) are intermediate hosts of B. darlingi, B. neotomofelis and B. oryctofelisi, respectively. Based on conserved regions in the internal transcribed spacer-1 (ITS1) sequence of the ribosomal DNA (rDNA), a real-time PCR for a sensitive detection of these Besnoitia spp. in tissues of intermediate hosts and faeces of definitive hosts has recently been established. Available sequence data suggest that species such as B. akodoni and B. jellisoni are also covered by this real-time PCR. It has been hypothesised that additional Besnoitia spp. exist worldwide that are closely related to B. darlingi or B. darlingi-like parasites (B. neotomofelis, B. oryctofelisi, B. akodoni or B. jellisoni). Also related, but not as closely, is B. besnoiti, the cause of bovine besnoitiosis. METHODS: Faecal samples from two free-ranging cheetahs (Acinonyx jubatus) from Namibia that had previously tested positive for coccidian parasites by coproscopy were used for this study. A conventional PCR verified the presence of coccidian parasite DNA. To clarify the identity of these coccidia, the faecal DNA samples were further characterised by species-specific PCRs and Sanger sequencing. RESULTS: One of the samples tested positive for B. darlingi or B. darlingi-like parasites by real-time PCR, while no other coccidian parasites, including Toxoplasma gondii, Hammondia hammondi, H. heydorni, B. besnoiti and Neospora caninum, were detected in the two samples. The rDNA of the B. darlingi-like parasite was amplified and partially sequenced. Comparison with existing sequences in GenBank revealed a close relationship to other Besnoitia spp., but also showed clear divergences. CONCLUSIONS: Our results suggest that a so far unknown Besnoitia species exists in Namibian wildlife, which is closely related to B. darlingi, B. neotomofelis, B. oryctofelisi, B. akodoni or B. jellisoni. The cheetah appears to be the definitive host of this newly discovered parasite, while prey species of the cheetah may act as intermediate hosts.


Asunto(s)
Acinonyx/parasitología , Coccidiosis/veterinaria , Sarcocystidae/clasificación , Sarcocystidae/genética , Animales , Animales Salvajes/parasitología , Coccidiosis/parasitología , Heces/parasitología , Especificidad del Huésped , Namibia , Filogenia , Sarcocystidae/aislamiento & purificación , Sarcocystidae/fisiología
16.
Front Vet Sci ; 8: 714758, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34490403

RESUMEN

Anthrax is a bacterial disease caused by Bacillus anthracis that affects wildlife, livestock and also humans in different parts of the world. It is endemic in some parts of Africa, including Namibia, with species differing in their susceptibility to the disease. Carnivores are typically less susceptible to anthrax than herbivores. Most carnivore species survive infection and have high seroprevalence against anthrax, whereas most herbivore species have low seroprevalence and typically die quickly when infected. Several reports have shown that cheetahs, unlike most other large carnivores, are susceptible to anthrax leading to a sudden death. This finding was suggested to be linked to the low genetic variability of cheetahs which might reduce an adequate immune response and thus explain such a high susceptibility to the disease. Here, we report an incidence of three free-ranging cheetahs that died within 24 h after feeding on a mountain zebra that tested positive for anthrax in the Namib Desert. We were able to reconstruct this incidence with the data recorded in the GPS (Global Positioning System) collar worn by one of the cheetahs and retrieved in the field. It is very likely that the cheetahs died from anthrax, although Bacillus anthracis could not be isolated from tissue and soil samples by bacterial culturing. The mountain zebra is the first described case of a wild animal that tested positive for anthrax in this arid area in southwestern of Namibia. We discuss the negative laboratory results of the cheetahs in the light of new insights of their immune system and its potential to mount a response against this bacteria.

17.
Parasit Vectors ; 14(1): 328, 2021 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-34134753

RESUMEN

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 (100.0%) than in SHTZ (32.0%). Only Anaplasma phagocytophilum/platys-like and Anaplasma bovis-like sequences were detected. Rickettsia raoultii was found in one BHNA and three SHTZ. This is the first report of R. raoultii from sub-Saharan Africa. Babesia lengau-like piroplasms were found in 70.6% of BHNA, 88.9% of SHNA and 32.0% of SHTZ, showing higher sequence diversity than B. lengau from South African cheetahs (Acinonyx jubatus). In one SHTZ, a Babesia vogeli-like sequence was identified. Hepatozoon felis-like parasites were identified in 64.7% of BHNA, 36.8% of SHNA and 44.0% of SHTZ. Phylogenetic analysis placed the sequences outside the major H. felis cluster originating from wild and domestic felids. Filarioids were detected in 47.1% of BHNA, 47.4% of SHNA and 36.0% of SHTZ. Phylogenetic analysis revealed high genetic diversity and suggested the presence of several undescribed species. Co-infections were frequently detected in SHNA and BHNA (BHNA median 3 pathogens, range 1-4; SHNA median 3 pathogens, range 2-4) and significantly rarer in SHTZ (median 1, range 0-4, 9 individuals uninfected). CONCLUSIONS: The frequencies of all pathogens groups were high, and except for Rickettsia, multiple species and genotypes were identified for each pathogen group. Ecological conditions explained pathogen identity and diversity better than host taxonomy.


Asunto(s)
Hyaenidae/microbiología , Hyaenidae/parasitología , Infecciones por Rickettsia/veterinaria , Enfermedades por Picaduras de Garrapatas/veterinaria , Anaplasmataceae/clasificación , Anaplasmataceae/genética , Anaplasmataceae/aislamiento & purificación , Infecciones por Anaplasmataceae/microbiología , Infecciones por Anaplasmataceae/veterinaria , Animales , Animales Salvajes/clasificación , Animales Salvajes/microbiología , Animales Salvajes/parasitología , Babesia/clasificación , Babesia/genética , Babesia/aislamiento & purificación , Babesiosis/parasitología , Coccidios/clasificación , Coccidios/genética , Coccidios/aislamiento & purificación , Coccidiosis/parasitología , Coccidiosis/veterinaria , Variación Genética , Hyaenidae/clasificación , Namibia , Filogenia , Rickettsia/clasificación , Rickettsia/genética , Rickettsia/aislamiento & purificación , Infecciones por Rickettsia/microbiología , Tanzanía , Enfermedades por Picaduras de Garrapatas/epidemiología , Enfermedades por Picaduras de Garrapatas/microbiología , Enfermedades por Picaduras de Garrapatas/parasitología
18.
Curr Biol ; 31(9): 1872-1882.e5, 2021 05 10.
Artículo en Inglés | MEDLINE | ID: mdl-33848458

RESUMEN

Leopards are the only big cats still widely distributed across the continents of Africa and Asia. They occur in a wide range of habitats and are often found in close proximity to humans. But despite their ubiquity, leopard phylogeography and population history have not yet been studied with genomic tools. Here, we present population-genomic data from 26 modern and historical samples encompassing the vast geographical distribution of this species. We find that Asian leopards are broadly monophyletic with respect to African leopards across almost their entire nuclear genomes. This profound genetic pattern persists despite the animals' high potential mobility, and despite evidence of transfer of African alleles into Middle Eastern and Central Asian leopard populations within the last 100,000 years. Our results further suggest that Asian leopards originated from a single out-of-Africa dispersal event 500-600 thousand years ago and are characterized by higher population structuring, stronger isolation by distance, and lower heterozygosity than African leopards. Taxonomic categories do not take into account the variability in depth of divergence among subspecies. The deep divergence between the African subspecies and Asian populations contrasts with the much shallower divergence among putative Asian subspecies. Reconciling genomic variation and taxonomy is likely to be a growing challenge in the genomics era.


Asunto(s)
Panthera , Animales , Asia , Gatos , Ecosistema , Genómica , Filogeografía
19.
Parasit Vectors ; 13(1): 7, 2020 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-31915056

RESUMEN

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) and site (natural habitat vs farmland). RESULTS: All but one carnivore species (bat-eared fox Otocyon megalotis, n = 4) were seropositive to T. gondii, with a seroprevalence ranging from 52.4% (131/250) in cheetahs to 93.2% (55/59) in African lions (Panthera leo). We also detected antibodies to T. gondii in 10.0% (2/20) of blue wildebeest (Connochaetes taurinus). Adult cheetahs and leopards were more likely to be seropositive to T. gondii than subadult conspecifics, whereas seroprevalence did not vary with sex, sociality and site. Furthermore, we measured antibodies to N. caninum in 15.4% (2/13) of brown hyenas (Hyaena brunnea) and 2.6% (1/39) of black-backed jackals (Canis mesomelas). Antibodies to B. besnoiti were detected in 3.4% (2/59) of African lions and 20.0% (4/20) of blue wildebeest. CONCLUSIONS: Our results demonstrate that Namibian wildlife species were exposed to apicomplexan parasites at different prevalences, depending on parasite and host species. In addition to serological work, molecular work is also needed to better understand the sylvatic cycle and the clear role of wildlife in the epidemiology of these parasites in southern Africa.


Asunto(s)
Animales Salvajes/parasitología , Anticuerpos Antiprotozoarios/sangre , Coccidiosis/veterinaria , Neospora/inmunología , Sarcocystidae/inmunología , Toxoplasma/inmunología , Animales , Animales Salvajes/sangre , Carnívoros/sangre , Carnívoros/parasitología , Coccidiosis/sangre , Coccidiosis/epidemiología , Coccidiosis/parasitología , Femenino , Masculino , Namibia/epidemiología , Neospora/aislamiento & purificación , Rumiantes/sangre , Rumiantes/parasitología , Sarcocystidae/aislamiento & purificación , Estudios Seroepidemiológicos , Especificidad de la Especie , Toxoplasma/aislamiento & purificación , Toxoplasmosis Animal/sangre , Toxoplasmosis Animal/epidemiología , Toxoplasmosis Animal/parasitología
20.
Nat Ecol Evol ; 3(1): 71-76, 2019 01.
Artículo en Inglés | MEDLINE | ID: mdl-30455441

RESUMEN

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.


Asunto(s)
Conducta Animal , Hyaenidae/fisiología , Conducta Social , Animales , Femenino , Masculino , Caracteres Sexuales
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