Basic Research in Infection Biology

Infectious diseases are caused by pathogens - viruses, bacteria, fungi or parasites - that enter and multiply within our bodies or colonize our skin or mucosal surfaces. Pathogens infect their hosts via distinct routes of transmission, for example through inhalation of aerosol droplets, intimate contact with infected hosts, consumption of contaminated food or the bites of disease-transmitting vectors such as mosquitoes or ticks.

Some pathogens invade multiple or particular types of cells in our body and propagate within them, whereas others remain extracellular and thrive for instance in the intestinal tract or in the bloodstream. Equally diverse are the symptoms associated with different kinds of infectious diseases – some elicit acute disease while others cause chronic infections, some take an asymptomatic or mild course yet others have severe or fatal consequences.

Elucidating Pathogen-Specific Biology

Independent of the type or kind of infectious agent, all pathogens evolved remarkable molecular strategies allowing them to successfully infect their hosts, to inhabit specific parts of our bodies, to tolerate or evade our immune defense mechanisms or to secure their transmission from one host to the next. Infection biologists employ a large number of different experimental approaches to elucidate the functional and mechanistic basis of such pathogen- and host-specific biology, and open up new avenues for the development of new diagnostics, drugs and vaccines.

We strive towards acquiring new scientific knowledge in the fields of

  1. pathogen virulence, survival and transmission;
  2. infection dynamics and pathogenesis;
  3. innate and adaptive immunity;
  4. mechanisms and evolution of drug resistance; and
  5. pathogen diversity, evolution and population structure.

Our researchers and students employ state-of-the-art methodology nested in the fields of molecular biology, cell biology, biochemistry, in vitro cell culture, immunology, microbiology, genetics, population biology and bioinformatics.

Our Research Units in the Department of Medical Parasitology and Infection Biology conduct cutting-edge basic research on infectious diseases of poverty including

  • Malaria (caused by Plasmodium spp.),
  • Tuberculosis (caused by Mycobacterium tuberculosis),
  • Buruli ulcer (caused by Mycobacterium ulcerans) and
  • Sleeping sickness, African trypanosomiasis (caused by Trypanosoma brucei).

Malaria and tuberculosis are two of the most devastating infectious diseases worldwide causing hundreds of millions of clinical cases each year. Buruli ulcer and African trypanosmiasis are so-called neglected tropical diseases that affect the poorest communities.

Malaria

A gametocyte - the sexual form of Plasmodium

Malaria is caused by unicellular parasites of the genus Plasmodium that are transmitted from human to human by mosquitoes. P. falciparum is accountable for the majority of severe and fatal malaria cases. P. falciparum blood stage parasites are our main study objects. We explore various crucial aspects of the biology of these intracellular parasites such as red blood cell invasion and remodeling pathways, antigenic variation or sexual differentiation. We are furthermore interested in understanding anti-parasite immunity in malaria pre-exposed populations and the mode-of-action of select anti-malarial drugs. 

Sleeping Sickness

Blue tsetse fly trap

Human African Trypanosomiasis (also known as sleeping sickness) is caused by the flagellated unicellular parasites of the species Trypanosoma brucei, which are transmitted via tsetse flies in several countries in sub-Saharan Africa. In humans, T. brucei multiplies extracellularly in the blood stream and lymphatic system, known as the first stage of the infection. The second stage of the infection, initiated by parasites crossing the blood-brain barrier, causes severe neurological complications and is fatal if untreated. We investigate the molecular mechanisms of drug resistance in T. brucei combining genetic and bioinformatic approaches.

Tuberculosis

M. tuberculosis bacteria

Human tuberculosis is caused by the bacterium Mycobacterium tuberculosis. M. tuberculosis infects and multiplies most commonly within lung macrophages and spreads between humans via air droplets released for instance through coughing or sneezing. One of the key problems in controlling tuberculosis is the widespread occurrence of multidrug-resistant M. tuberculosis bacteria. We combine several experimental approaches to study the evolution, distribution and ecology of M. tuberculosis drug resistance, to carry out in-depth analyses of global M. tuberculosis genome diversity and to investigate aspects of co-evolution of M. tuberculosis and human populations. We also ask how co-occuring diseases (co-morbidities), for instance diabetes mellitus or helminth infections, impact on tuberculosis-specific immunity.  

Buruli Ulcer

Young man with buruli ulcer

Buruli ulcer is a necrotizing skin disease that is caused by Mycobacterium ulcerans and primarily affects people living in Western Africa. The exact mode of transmission of M. ulcerans is still unknown but aquatic ecosystems are believed to play a central role. Unlike other mycobacterial pathogens (such as M. tuberculosis) M. ulcerans thrives mainly in the extracellular environment and causes its devastating pathology through secretion of a toxin known as mycolactone. We explore the molecular and cellular mechanisms linked to Buruli ulcer pathogenesis, immunology and transmission and try to decipher the pathway responsible for mycolactone-induced tissue destruction.