An important goal of research in immunology is to understand the flaws in the human immune system, such that their impacts can be effectively mitigated. Previous work documented flaws in the mechanisms by which the immune system tempers its responses to pathogens in order to avoid harming the host. As explained here, these tempering mechanisms also govern the phenomenon of the original antigenic sin, whereby an encounter with a new pathogen strain preferentially recalls less potent immune responses directed against an older, moderately different strain.
Other infectious diseases
As a PhD student in Ecology and Evolutionary Biology, I have spent more than half of the past four years of my dissertation work in Madagascar, where I study the transmission dynamics of zoonotic viruses which jump the species barrier from bat reservoirs to human hosts. I combine field, laboratory, and modeling methods, with each technique offering unique insights into the larger truth.
We conducted surveys of travellers and their movement patterns in Mali, Burkina Faso, Zambia and Tanzania. We found that women travelling with children are a consistent group of relevance to malaria transmission. Our study also highlighted youth workers as a key traveller group of relevance to parasite dispersal in Mali.
The objective of my thesis was to develop a novel, parameterised mechanistic mathematical model which describes the dynamics of parasite invasion during the initial stages of malarial infection.
Soil transmitted helminths infections can have a negative impact on the health of children affecting nutritional status and development. Therefore, most endemic countries have started implementing mass chemotherapy programmes through school infrastructures. The success of a national deworming programme may be influenced by environmental conditions or the access to water, sanitation and hygiene. The question is which of these factors lead to success or failure of a programme. We therefore tried to get a better understanding of the determinants of geographical variations in programme impact in Kenya.
Schistosomiasis (bilharzia) is a parasitic disease which mainly affects under-resourced communities, especially in rural areas and is often not prioritized in national budgets in sub-Saharan African countries. The spatial and temporal distribution of schistosomiasis is mainly determined by the distribution of the intermediate host freshwater snail species. This is well-known, but the distribution is difficult to predict. The development of geospatial technology including GIS and remote sensing or earth observation has facilitated the progress made in predicting or modelling schistosomiasis in Africa.
Leprosy is caused by infection with Mycobacterium leprae and is characterized by peripheral nerve damage and skin lesions. Globally, new case detection rates for leprosy have remained fairly stable in the past decade, with India responsible for more than half of cases reported annually. We took a statistical look at recent annual new case detection trends reported by the government of India’s National Leprosy Eradication Programme. We found evidence of a very slow declining trend, but with substantial differences between districts. Enhancements in current public health policy must be undertaken to hasten the decline of leprosy.
Tsetse flies (genus Glossina) can threaten health and agriculture by transmitting the parasites that cause the potentially fatal diseases of sleeping sickness in humans and nagana in livestock. The fact that only parts of sub-Saharan Africa are infested is attributable to many causes, including the temperature in the area. This raises the possibility that climate change will affect the abundance and distribution of tsetse – the leading questions being how great and how rapid the effects will be. SACEMA is addressing these questions by a combination of field work and simulation modelling.
Africa and Asia have the highest prevalence of Hepatitis B virus (HBV) worldwide. Mother-to-child transmission (MTCT) is the most common route of transmission in high prevalence areas. There are three different prevention strategies available to prevent HBV MTCT: Vaccine, Hepatitis B Immunoglobulin and Antiviral therapy during pregnancy. Strategic investment now could see the eradication of HBV MTCT in Africa and ultimately potentially the elimination of this major public health problem.
The evolutionary origin of Ebolaviruses is not very clear. The simple notion that these viruses have been circulating for many millennia in wildlife in tropical parts of Africa, occasionally spilling over into human populations, often brought on by human activities, may not be correct or at least incomplete. Over time a number of Ebola disease outbreaks reported and a pattern in the outbreak response seemed to have been established. A lot was also learnt about Ebola viruses, their epidemiology and ecology.
However, the 2014 Ebola outbreak challenges our understanding in many respects.