I have been addressing the interplay between pathogens and host health and behaviour from different angles: 

In my Ph.D., I capitalized on routine anthelmintic treatment of my study population of Barbary macaques, allowing me to use an experimental study design. Working completely non-invasively, I used a range of physiological markers and detailed behavioural observation to investigate both directions of the host-pathogen relationship between the macaques and their gastrointestinal parasites: I investigated the effect of parasite infections on individual social behaviour, immune function and physiology to assess the costs of infections. I also assessed the behavioural and physiological host characteristics contributing to individual reinfection risk, simultaneously measuring parasite exposure and susceptibility.

Currently, I am privileged to be part of a collaboration with the Kalahari Meerkat Project and benefit from the wealth of long-term data available. I am working on tuberculosis infections reported in the study population since the late 1990s, aiming at quantifying and explaining variation in tuberculosis infection courses. I am focussing on the role of host immune genes for susceptibility and resistance to infections, assessing major histocompatibility complex (MHC) gene composition and functional diversity. Beyond the level of individual susceptibility and resistance, I am investigating the possibility of TB-mediated selection and the corresponding effect of the pathogen on population dynamics. Another research trajectory are the Trace-amine-associated receptors, which are implicated to play a role in olfactory communication and mate choice, to test whether they are involved in meerkats migration and mate choice decisions, in concert with MHC constitution.

Müller-Klein N, Risely A, Schmid D W, Manser M, Clutton-Brock T, Sommer S (2022). Two decades of tuberculosis surveillance reveal disease spread, high levels of exposure and mortality, and marked variation in disease progression in wild meerkats. Transboundary and Emerging Diseases.

Sadoughi B, Anzà S, Defolie C, Manin V, Müller-Klein N, Murillo T, Ulrich M, Wu D (accepted) Parasites in a social world: Lessons from primates. In: Animal Behavior and Parasitism. Edited by Vanessa Ezenwa, Sonia Altizer, and Richard Hall, Oxford University Press.

Risely A, Schmid D, Müller-Klein N, Wilhelm K, Clutton-Brock T, Sommer S (2022) Gut microbiota individuality is contingent on temporal scale and age in wild meerkats. Proceedings of the Royal Society B.

Donadio J, Risely A, Müller-Klein N, Wilhelm K, Clutton-Brock T, Manser M B, & Sommer S (2022). Characterizing tuberculosis progression in wild meerkats (Suricata suricatta) from fecal samples and clinical signs. The Journal of Wildlife Diseases, 58(2), 309-321.

Schülke O, Anzà S, Crockford C, De Moor D, Deschner T, Fichtel C, Gogarten J, Kappeler P, Manin V, Müller-Klein N, Prox L, Sadoughi B, Touitou S, Wittig R, Ostner, J. (2022). Quantifying within-group variation in sociality—covariation among metrics and patterns across primate groups and species. Behavioral Ecology and Sociobiology, 76(4), 1-18.

Behringer V, Müller-Klein N, Strube C, Schülke O, Heistermann M, Ostner J (2021). Responsiveness of fecal immunoglobulin A to HPA-axis activation limits its use for mucosal immunity assessment. American Journal of Primatology, 83(12), e23329.

Gogarten J, Calvignac-Spencer S, Nunn C, Ulrich M, Saiepour N, Nielsen H, Deschner T, Fichtel C, Kappeler P, Knauf S, Müller-Klein N, Ostner J, Robbins M, Sangmaneedet S, Schülke O, Surbeck M, Wittig R, Sliwa A, Strube C, Leendertz F, Roos C, Noll A (accepted) Metabarcoding of eukaryotic parasite communities describes diverse parasite assemblages spanning the primate phylogeny. Molecular Ecology Resources.

Müller-Klein N, Heistermann M, Strube C, Schülke O, Ostner J (2019) Exposure and susceptibility drive reinfection with gastrointestinal parasites in a social primate.
Functional Ecology, 33, 1088 – 1098.

Müller-Klein N, Heistermann M, Strube C, Morbach Z, Lilie N, Franz M, Schülke O, Ostner J (2019) Physiological and social consequences of gastrointestinal nematode infection in a nonhuman primate. Behavioural Ecology, 30 (2), 322–335.

Paschek N, Müller N, Heistermann M, Ostner J, Schülke O (2019) Subtypes of aggression and their relation to anxiety in Barbary macaques. Aggressive Behaviour, 45, 120 – 128.

Müller N, Heistermann M, Strube C, Schülke O, Ostner J (2017) Age, but not anthelmintic treatment, is associated with urinary neopterin levels in semi-free ranging Barbary macaques. Scientific Reports, 7, 41973.

Müller N, Ostner J, Schülke O, Walter L (2014) Towards the non-invasive assessment of MHC genotype in wild primates: Analysis of wild Assamese macaque MHC-DRB from faecal samples. American Journal of Primatology, 3, 230 – 238.