Multi-Scale Predictors of Parasite Risk in Wild Male Savanna Baboons (Papio Cynocephalus)

Several factors are thought to shape male parasite risk in polygynous and polygynandrous mammals, including male-male competition, investment in potentially immunosuppressive hormones, and dispersal. Parasitism is also driven by processes occurring at larger scales, including host social groups and populations. To date, studies that test parasite-related costs of male behavior at all three scales—individual hosts, social groups, and the host population—remain rare. To fill this gap, we investigated multi-scale predictors of helminth parasitism in 97 male savanna baboons (Papio cynocephalus) living in the Amboseli ecosystem in Kenya over a 5-year span. Controlling for multi-scale processes, we found that many of the classic indicators of male mating effort—high dominance rank, testosterone, and glucocorticoids—did not predict helminth infection risk. However, we identified two parasite-related costs associated with male behavior: (i) socially connected males exhibited higher Trichuris trichiura egg counts and greater parasite species richness than socially isolated males and (ii) males with stable group residency exhibited higher parasite species richness than males who frequently dispersed to new social groups. At the population level, males harbored more parasites following periods of drought than rainfall. Lastly, parasites exhibited positive covariance suggesting that infection risk increases if a host already harbors one or more parasite taxa. These results indicate that multi-scale processes are important in driving male parasite risk and that some aspects of male behavior are costly. Together, our results provide an unusually holistic perspective on the drivers of parasite risk in the context of male behaviors and life histories

Distinct transcriptomic signatures define febrile malaria depending on initial infective states, asymptomatic or uninfected

Background: Cumulative malaria parasite exposure in endemic regions often results in the acquisition of partial immunity and asymptomatic infections. There is limited information on how host-parasite interactions mediate the maintenance of chronic symptomless infections that sustain malaria transmission. Methods: Here, we determined the gene expression profiles of the parasite population and the corresponding host peripheral blood mononuclear cells (PBMCs) from 21 children ( Results: Children with asymptomatic infections had a parasite transcriptional profile characterized by a bias toward trophozoite stage (~ 12 h-post invasion) parasites and low parasite levels, while early ring stage parasites were characteristic of febrile malaria. The host response of asymptomatic children was characterized by downregulated transcription of genes associated with inflammatory responses, compared with children with febrile malaria,. Interestingly, the host responses during febrile infections that followed an asymptomatic infection featured stronger inflammatory responses, whereas the febrile host responses from previously uninfected children featured increased humoral immune responses. Conclusions: The priming effect of prior asymptomatic infection may explain the blunted acquisition of antibody responses seen to malaria antigens following natural exposure or vaccination in malaria endemic areas

Ancient Pathogens Provide a Window Into Health and Well-Being

This perspective draws on the record of ancient pathogen genomes and microbiomes illuminating patterns of infectious disease over the course of the Holocene in order to address the following question. How did major changes in living circumstances involving the transition to and intensification of farming alter pathogens and their distributions? Answers to this question via ancient DNA research provide a rapidly expanding picture of pathogen evolution and in concert with archaeological and historical data, give a temporal and behavioral context for heath in the past that is relevant for challenges facing the world today, including the rise of novel pathogens

Data from: Role of grooming in reducing tick load in wild baboons (Papio cynocephalus)

Nonhuman primate species spend a conspicuous amount of time grooming during social interactions, a behaviour that probably serves both social and health-related functions. While the social implications of grooming have been relatively well studied, less attention has been paid to the health benefits, especially the removal of ectoparasites, which may act as vectors in disease transmission. In this study, we examined whether grooming behaviour reduced tick load (number of ticks) and haemoprotozoan infection status in a population of wild adult baboons (Papio cynocephalus). We found that younger and higher-ranking adults were groomed more often than older, low-ranking adults, and females were groomed more often than males. Animals that received more grooming, in turn, had lower tick loads. Baboons with lower tick loads had higher packed red cell volume (PCV or haematocrit), one general measure of health status. We detected a tick-borne haemoprotozoan, Babesia microti, but its low prevalence in the population precluded identifying sources of variance in infection

Role of Grooming in Reducing Tick Load in Wild Baboons (Papio cynocephalus)

Nonhuman primate species spend a conspicuous amount of time grooming during social interactions, a behavior that probably serves both social and health-related functions. While the social implications of grooming have been relatively well studied, less attention has been paid to the health benefits, especially the removal of ectoparasites, which may act as vectors in disease transmission. In this study, we examined the relationship between grooming behavior, tick load (number of ticks), and haemoprotozoan infection status in a population of wild free-ranging baboons (Papio cynocephalus). We found that the amount of grooming received was influenced by an individual’s age, sex and dominance rank. The amount of grooming received, in turn, affected the tick load of an individual. Baboons with higher tick loads had lower packed red cell volume (PCV or haematocrit), one general measure of health status. We detected a tick-borne haemoprotozoan, Babesia microti, but its low prevalence in the population precluded identifying sources of variance in infection

Hormonal correlates of natal dispersal and rank attainment in wild male baboons

In many mammals, maturational milestones such as dispersal and the attainment of adult dominance rank mark stages in the onset of reproductive activity and depend on a coordinated set of hormonal and socio-behavioral changes. Studies that focus on the link between hormones and maturational milestones are uncommon in wild mammals because of the challenges of obtaining adequate sample sizes of maturing animals and of tracking the movements of dispersing animals. We examined two maturational milestones in wild male baboons—adult dominance rank attainment and natal dispersal—and measured their association with variation in glucocorticoids (fGC) and fecal testosterone (fT). We found that rank attainment is associated with an increase in fGC levels but not fT levels: males that have achieved any adult rank have higher fGC than males that have not yet attained an adult rank. This indicates that once males have attained an adult rank they experience greater energetic and/or psychosocial demands than they did prior to attaining this milestone, most likely because of the resulting participation in both agonistic and sexual behaviors that accompany rank attainment. In contrast, natal dispersal does not produce sustained increases in either fGC or fT levels, suggesting that individuals are either well adapted to face the challenges associated with dispersal or that the effects of dispersal on hormone levels are ephemeral for male baboons

Summary of parasites in a wild baboon population

This data set is a summary of the parasites collected for the study reported in Akinyi et al. 2013, Animal Behaviour, (Role of grooming in reducing tick load in wild baboons (Papio cynocephalus)). The table indicates the types of parasites encountered and their relative abundance in the darted individuals. The ectoparasites data are presented by the species of ticks collected and the number collected in each animal. The blood parasite data indicate the haemoparasites screened for by PCR and whether the individuals screened were positive or negative

Grooming and ectoparasite load in wild baboons.

This data set underlies results presented in Akinyi et al. 2013, Animal Behaviour, (Role of grooming in reducing tick load in wild baboons (Papio cynocephalus)). The study was conducted on adult members of a wild baboon population in Amboseli, southern Kenya. The data set includes demographic data on individual age, sex and group membership, as well as behavioural data on grooming and dominance rank. The dataset also includes tick counts and packed cell volume (PCV) analysis from baboons darted during darting and immobilization projects in 2007–2008. Subject numbers represent each individual data was collected for. Sex describes whether the individual was female (F) or male (M). Year darted indicates the year in which each individual was darted. Age describes each individual’s age (to the nearest year) at darting. Social group at darting categorises the group each individual belonged to at the time of darting and group size indicates the total number of individuals in the group during the six months that grooming data was retrieved. Grooming counts 6 months prior to darting contains the counts of grooming received by each study animal in the 6 months prior to their darting date. Mean PCV at darting is calculated from the average of two to three replicate PCV measurements were obtained per animal during darting. Adult and larvae tick counts are the number of ticks collected and counted from each individual. These data were extracted from the long-term relational database for the Amboseli Baboon Research Project, BABASE