top of page

Field report: The "Zoonosis Hunters" - How you can work with wild animals for One Health

Updated: Nov 30, 2022

„Sumatra est mort!“ (Sumatra is dead.) When this news reaches me on 01 August 2021, I am a member of a field mission of the Project Group P3 - Epidemiology of Highly Pathogenic Pathogens of the Robert Koch Institute to sample rodents, shrews and bats in Taï National Park, Ivory Coast. Sumatra was a habituated chimpanzee, which means tolerating observation by researchers, of the Taï Chimpanzee Project (TCP), for which I am also responsible as a leave replacement of the supervising veterinarian. Since my supervisor, Prof. Dr. Fabian Leendertz, discovered the deadly zoonotic bacterium Bacillus cereues biovar anthracis (an anthrax pathogen) in the course of his doctoral thesis more than 20 years ago, his research group has been working regularly there and in other countries of West and Central Africa and is dedicated to the study of zoonotic pathogens. Chimpases in particular are good "filters" for pathogens that are also relevant to humans because of their close relationship to humans.


Sampling of a flying fox of the species Epomops franqueti (©Kamilla Pléh)

When I learn of Sumatra's death, I know that I have to get to her as soon as possible to perform an autopsy. Before, in the morning we have tried to reach our rodent traps. However, the entire forest was flooded meters high after heavy rain. The bridge leading over a river nearby has disappeared in the floods. Nevertheless, we have to set off: Together with an Ivorian assistant and my experienced colleague Kamilla, who will assist me in the correct biosafety and autopsy techniques, we are lucky: The water is only waist-high anymore, so we can start the several-hour hike through the jungle without major difficulties. After an hour we arrive at the southern camp of TCP, where we pick up not only autopsy equipment but also material for a brain extraction. Sumatra's samples will be examined for several kinds of pathogens, whereas the brain serves as an important sample for the Evolution of Brain Connectivity (EBC) project of the Max Planck Institute for Evolutionary Anthropology in Leipzig.

Another two hours later we arrive at Sumatra's body and are sadly touched. It is covered with carnivorous army ants. The assistants on site tell us that the chimpanzee, who was 52 years old and weakened from a leopard attack, has fallen out of her nest that morning due to weakness and landed in the ants' burrow. From there she did not manage to move until her death.

It is important here to have the right understanding of animal welfare when working with habituated chimpanzees: humans should not have any interaction with the animals and only intervene in case of human-induced diseases. Hence, when working with wildlife, it is important to remember that any intervention in such a complex and finely adjusted ecosystem, may lead to unpredictable and sometimes drastic damage of the ecological balance. Thus, it is critical see animal welfare issues in the context of their linkages to the environment and the chimpanzee population as a whole. Natural disease and death are a part of chimpanzee life. Artificially prolonging their lives could, for example, further spread disease or artificially deplete resources for healthy and growing animals. Thus, a rescue attempt in this situation should be rejected due to unpredictable but potentially harmful effects for the chimpanzee population, even if our compassion and conscience tells us something else. For more, see the "Best practice guidelines for health monitoring and diesease control in great ape populations" from the IUCN (International Union for Conservation of Nature), which develops international standards for environmental and conservation issues.


Prepararion of brain extraction of chimp Sumatra (© Kamilla Pléh)


With help of Rambo, the all-purpose insecticide in the jungle, we can finally prepare the autopsy without becoming victims of the ants ourselves. Wearing BSL3-compliant personal protective equipment (PPE, consisting of a Tyvek overall, FFP3 mask and face shield, triple layer of protective gloves with arm sleeves and protective boots), we set up a hygiene barrier more than ten meters away. No one is allowed to get any closer without protective clothing. Five strenuous hours with PPE in 27 degrees, with 100% humidity and incipient darkness begin. The skull is opened with a bone saw, the brain is carefully extracted and transferred to a preservation medium (3 hours).

Then, I open the body and take samples of all internal organs, Sumatra's wounds and her skin. An Extensive pathological-anatomical examination and diagnosis is impossible due to the circumstances, but the absence of acute pathological changes, her highly emaciated nutritional state, and the chronically inflamed bite wounds from the leopard attack indicate a chronic disease process. Finally, Sumatra's body is buried in a previously excavated pit to prevent contact to other animals. After the work is done, we begin the three-hour return journey and arrive at the research station, which we had left at noon, at 2:00 a.m.. Then, we spend the next hours sorting the samples and storing them in liquid nitrogen for later cultivation and molecular biological analyses, finally falling dead tired into our musty mattresses at 5:00 am.

Besides working with chimpanzees, as mentioned above, an important scientific focus of my research group is working with wild small mammals, which play a key role as hosts of many zoonotic pathogens. During my work, which focuses on the interface of these small mammals with the environment and humans, I was twice part of an international team investigating the relationship between biodiversity and infectious disease incidence as part of the BiodivAfreid project, sampling bats, rodents, and shrews in Côte d'Ivoire. At the same time, my research group has grown from a part of the Robert Koch Institute in Berlin to the Helmholtz-Institute for One Health (HIOH) Greifswald, a branch of the Helmholtz-Centre for Infection Research (HZI). At the HIOH, in addition to opportunities for doctoral theses, there are also opportunities to work with wildlife through internships and to learn about the highly relevant field of One Health.


Jonas Steiner


99 views0 comments

Recent Posts

See All
bottom of page