Human activities link fruit bat presence to Ebola virus disease outbreaks

1. A significant link between forest loss and fragmentation and human outbreaks of Ebola virus disease (EVD) has been documented. Deforestation may alter the natural circulation of viruses as well as change the composition, abundance, behaviour and possibly viral exposure of reservoir species. This in turn might increase contact between infected animals and humans. Fruit bats of the family Pteropodidae have been suspected as reservoirs of the Ebola virus. Though there is no solid proof that fruit bats cause human EVD outbreaks, this group of animals have been intermittently infected with the Ebola virus. 2. Our study investigates whether human activities positively affect African fruit bat species’ ranges and whether their ranges are linked to EVD outbreaks, in turn favoured by deforestation. 3. We use species observation records for the 20 fruit bat species found in Africa to determine factors affecting their distribution in two geographical scenarios: 1) the African continent; and 2) inside the predicted Ebola virus range. We do this by employing a hypothetico-deductive approach based on favourability modelling. 4. Our models point to clear associations between human activities and fruit bat distributions that may help scientists understand the anthropogenic settings that could cause the Ebola virus to jump from animals to humans. 5. We show that fruit bat distributions are linked to human activities throughout Africa and particularly within the region where the Ebola virus occurs. More specifically, the areas where human activities favour the presence of five fruit bat species (four of which had recorded seropositive individuals) overlap with EVD outbreak areas, themselves favoured by deforestation. 6. Our work is a useful first step to further investigate the networks and pathways that may lead to an EVD outbreak. The modelling framework we employ here can be employed for other emerging infectious diseases

Differential food preferences in three co-occurring species of <i>Tisbe</i> (Copepoda, Harpacticoida)

Killed samples of a monoclonal bacterial strain and an axenic alga were offered in different proportions to Tisbe holothuriae, T. battagliai and T. furcata. Incorporation of carbon ranged from 0.05 and 0.39 µg C (adult male)-1 d-1. Using a radiolabelling technique, the ratio in which the two food types were assimilated was compared to the ratio in which they were offered. Neither T. holothuriae nor its sibling species fed selectively under our conditions, but T. furcata showed a clear preference for bacteria. These findings constitute the first evidence for intrageneric dietary differentiation in harpacticoids. The results of the feeding experiments parallel observed differences in mandible structure. They render all the more acute the problem of resource partitioning between T. holothuriae and T. battagliai

Statistical Mechanics of Broadcast Channels Using Low Density Parity Check Codes

We investigate the use of Gallager's low-density parity-check (LDPC) codes in a broadcast channel, one of the fundamental models in network information theory. Combining linear codes is a standard technique in practical network communication schemes and is known to provide better performance than simple timesharing methods when algebraic codes are used. The statistical physics based analysis shows that the practical performance of the suggested method, achieved by employing the belief propagation algorithm, is superior to that of LDPC based timesharing codes while the best performance, when received transmissions are optimally decoded, is bounded by the timesharing limit.Comment: 14 pages, 4 figure

Statistical Mechanics of Broadcast Channels Using Low Density Parity Check Codes

We investigate the use of Gallager's low-density parity-check (LDPC) codes in a broadcast channel, one of the fundamental models in network information theory. Combining linear codes is a standard technique in practical network communication schemes and is known to provide better performance than simple timesharing methods when algebraic codes are used. The statistical physics based analysis shows that the practical performance of the suggested method, achieved by employing the belief propagation algorithm, is superior to that of LDPC based timesharing codes while the best performance, when received transmissions are optimally decoded, is bounded by the timesharing limit.Comment: 14 pages, 4 figure