Preparedness, Prediction and Prevention of Emerging Zoonotic Viruses with Pandemic Potential Using Multidisciplinary Approaches
Institut Pasteur, France, on behalf of the PREDEMICS consortium
Most emerging infectious diseases of humans are zoonotic and represent a persistent global threat. In a One Health approach, the FP7 PREDEMICS project (http://predemics.biomedtrain.eu) aims to unravel the complex interactions between factors involved in the various stages of emergence of zoonotic RNA viruses (lyssaviruses, Ebola disease virus, HEV, arboviruses, influenza A virus and MERS coronavirus) representing key transmission routes. Environmental, ecological and anthropological factors involved in species-barrier crossover, virus detection and/or serological data, were collected for LYSV and HEV from the environment, wild and domestic hosts and compared to data from humans thus shedding light on virus circulation over time, geographic spread and transmission. Molecular phylodynamics studies provided information on the conditions of dispersal and contribution of multiple introductions to epidemiologic waves and establishment of endemic circulation. Phylodynamic investigations applied to the HIN1pdm09 or H7N9 influenza viruses or the recently emerged MERS-CoV.and EBOV, provided real-time estimates of the evolutionary rate, date of emergence and intrinsic growth rate (R0).
Replication efficiency, pathogenesis and transmissibility in natural hosts were studied for the different viruses pointing for instance to molecular determinants involved in IAV cross-species transmission and adaptation from avian to mammalian hosts. Mechanisms of evasion of the host innate immunity by the different viruses (IAV, WNV, LYSV) were uncovered. Mapping methods for animal (reservoir and vector) distribution, behaviour- and models were developed that were used to study the dynamics of lyssavirus, flavivirus, influenza virus and the newly emerging MERS-CoV, CHIKV and EBOV.
Through its cross-disciplinary expertise in veterinary and human medicine, PREDEMICS thus provides a platform for global analysis of the factors involved, causal mechanisms, potential risk, and conditions favoured for emergence, maintenance, epidemic and potentially pandemic expansion of diseases in humans due to zoonotic viruses and also to describe strategies to control and mitigate the burden of those diseases.
The Economic Dimension Of Vector-Borne Disease Ecology: Public Costs Of Aedes Albopictus Control In Europe, A Case Study
University of Bologna, Italy
Aedes albopictus, or Asian tiger mosquito, invaded in the last decades a wide area of the World and is considered one of the most invasive mosquito species, with a very aggressive behaviour and specific aptitudes to infest urban ecosystems. It is also a known vector of important human and animal diseases, especially caused by viruses and nematodes, and has proved capacity for local transmission of Chikungunya and Dengue within Europe. Its global expansion has been facilitated by growth of international trade and movement of people. Prevention of diseases vectored by this Culicidae largely depends on the management of the ecological factors, which boost the spreading and the intensity of infestations. This research evaluated public costs related to the implementation of the Plan for A. albopictus control and Chikungunya and Dengue prevention set up in Emilia-Romagna region (Northern Italy), where a Chikungunya epidemic outbreak occurred in 2007 with 247 people infected. The Plan started in 2008 by involving more than 280 municipalities and 4.3 million inhabitants within the region. The Plan’s activities mainly target the ecological conditions for the multiplication of infestation hotspots in urban areas to reduce the probability of rapid and uncontrolled disease spreading in case of outbreaks: this includes monitoring the infestation intensity, larvicide treatments in public and private areas, adulticide emergency treatments to isolate disease outbreaks, information in schools and to citizens, and compulsory good practices. The study accessed to data on the expenditure supported by all the public institutions involved in the implementation of the Plan. Main results include: evaluation of public costs related to some key indicators (inhabitants, extension of urban areas, type of treatments, etc.), analysis of differences in expenditure among municipalities and correlation between expenditure and socio-economic and environmental factors, as well as recommendations to improve the Plan’s economic efficiency and management.
The Epidemiology of Q Fever in Western Kenya.
1University of Southampton, United Kingdom; 2University of Edinburgh, United Kingdom; 3Kenya Medical Research Institute, Kenya; 4University of Liverpool, United Kingdom
Evidence suggests that the intracellular bacterial pathogen Coxiella burnetii (which causes Q fever) is widespread, with a near global distribution. While there has been increasing attention to Q fever epidemiology in high-income settings, a recent systematic review highlighted significant gaps in our understanding of the prevalence, spatial distribution and risk factors for Q fever infection across Africa. This research aims to provide a One Health assessment of Q fever epidemiology in western Kenya in cattle and humans.
A cross-sectional survey was conducted: serum samples from 2113 humans and 983 cattle in 416 homesteads were analysed for C. burnetii antibodies. Questionnaires covering demographic, socio-economic and husbandry information were also administered. These data were linked to environmental datasets based on geographical locations (e.g. land cover). Multilevel regression analysis was used to assess the relationships between a range of socio-economic, demographic and environmental factors and sero-positivity in both humans and animals.
The overall sero-prevalence of C. burnetii was 2.5% in humans and 10.5% in cattle. Multilevel modelling indicated the importance of several factors for exposure to the organism. Cattle obtained from market (as opposed to those bred in their homestead) and those residing in areas with lower precipitation levels had the highest sero-prevalence. For humans, the youngest age group had the highest odds of seroprevalence, variations were observed between ethnic groups, and frequent livestock contact (specifically grazing and dealing with abortion material) was also a risk factor.
These results illustrate endemnicity of C. burnetii in western Kenya, although prevalence is relatively low. The analysis indicates that while environmental factors may play a role in cattle exposure patterns, human exposure patterns are likely to be driven more strongly by livestock contacts. The implication of livestock markets in cattle exposure risks suggests these may be a suitable target for interventions.