Health monitoring in birds using bio-loggers and whole blood transcriptomics

Elinor Jax,Inge Müller,Wolfgang Fiedler,Karsten Klein,Falk Schreiber,Hanna Borlinghaus,Bernd Timmermann,Gustaw Eriksson,Evi Fricke,Martin Wikelski,Stefan Börno,Robert H S Kraus,Katharine E Magor,Helene Pendl

doi:10.1038/s41598-021-90212-8

Abstract

Monitoring and early detection of emerging infectious diseases in wild animals is of crucial global importance, yet reliable ways to measure immune status and responses are lacking for animals in the wild. Here we assess the usefulness of bio-loggers for detecting disease outbreaks in free-living birds and confirm detailed responses using leukocyte composition and large-scale transcriptomics. We simulated natural infections by viral and bacterial pathogens in captive mallards (Anas platyrhynchos), an important natural vector for avian influenza virus. We show that body temperature, heart rate and leukocyte composition change reliably during an acute phase immune response. Using genome-wide gene expression profiling of whole blood across time points we confirm that immunostimulants activate pathogen-specific gene regulatory networks. By reporting immune response related changes in physiological and behavioural traits that can be studied in free-ranging populations, we provide baseline information with importance to the global monitoring of zoonotic diseases.

Highlights

Monitoring and early detection of emerging infectious diseases in wild animals is of crucial global importance, yet reliable ways to measure immune status and responses are lacking for animals in the wild
Learning about the acute-phase response (APR) in reservoir species is important for understanding their potential role in the spread of zoonotic diseases, and monitoring their APR in the field could be used as a warning system for disease outbreaks
The maximum mean temperature in the polycytidylic acid (poly I):C group was reached after 4.1 hps (n = 3, mean 42.04 °C, 95% Credible Intervals (CrI) 41.63–42.45 °C) and was elevated until 10.5 hps

Summary

Introduction

Monitoring and early detection of emerging infectious diseases in wild animals is of crucial global importance, yet reliable ways to measure immune status and responses are lacking for animals in the wild. Rapid advances in and decreased costs of generation DNA and RNA sequencing technologies allow researchers to study the underlying mechanisms of the APR in non-model species, and provides disease markers for studying immune status and responses in wild populations[20,21,22] While these technological advances have been used to study changes in behaviour23, physiology[24] and regulation of immune genes in free-living animals[25], they have so far not been studied simultaneously during the APR in reservoir species of zoonotic diseases. Further we wanted to identify k nown[20,26] and novel candidate genes that are upregulated during different stages of the APR and in response to different pathogens, in tissues that can and repeatably be collected in free-living birds For this purpose, we experimentally induced immune responses in an important natural vector for avian influenza virus (AIV), the mallard (Anas platyrhynchos)[27,28]. Our specific aims were to (1) examine the magnitude and timing of changes in the bio-logged parameters, (2) assess whether a correspondent immune response can be detected in global gene expression profiles from whole blood, and (3) determine the specificity of the immune response to different stimulants, using transcriptomics and gene regulatory network analyses

Objectives

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Conclusion