The intrinsic vulnerability of networks to epidemics

Contact networks are convenient models to investigate epidemics, with nodes and links representing potential hosts and infection pathways, respectively. The outcomes of outbreak simulations on networks are driven both by the underlying epidemic model, and by the networks’ structural properties, so that the same pathogen can generate different epidemic dynamics on different networks. Here we ask whether there are general properties that make a contact network intrinsically vulnerable to epidemics (that is, regardless of specific epidemiological parameters). By conducting simulations on a large set of modelled networks, we show that, when a broad range of network topologies is taken into account, the effect of specific network properties on outbreak magnitude is stronger than that of fundamental pathogen features such as transmission rate, infection duration, and immunization ability. Then, by focusing on a large set of real world networks of the same type (potential contacts between field voles, Microtus agrestis), we showed how network structure can be used to accurately assess the relative, intrinsic vulnerability of networks towards a specific pathogen, even when those have limited topological variability. These results have profound implications for how we prevent disease outbreaks; in many real world situations, the topology of host contact networks can be described and used to infer intrinsic vulnerability. Such an approach can increase preparedness and inform preventive measures against emerging diseases for which limited epidemiological information is available, enabling the identification of priority targets before an epidemic event

Monogenoidean parasites of fishes associated with coral reefs in the Ras Mohammed National Park, Egypt: preliminary results

AbstractA parasitological survey of the monogenoids of 14 species of common fishes associated with the local coral reefs of the Ras Mohammed National Park, National Parks of Egypt South Sinai Sector, Egypt, was carried out from May 2003 to May 2005. The monogenoids collected during the survey included 17 species: 8 previously described species, 7 new species in established genera, and 2 new species belonging to new genera

Small room for compromise between oil palm cultivation and primate conservation in Africa

Despite growing awareness about its detrimental effects on tropical biodiversity, land conversion to oil palm continues to increase rapidly as a consequence of global demand, profitability, and the income opportunity it offers to producing countries. Although most industrial oil palm plantations are located in Southeast Asia, it is argued that much of their future expansion will occur in Africa. We assessed how this could affect the continent’s primates by combining information on oil palm suitability and current land use with primate distribution, diversity, and vulnerability. We also quantified the potential impact of large-scale oil palm cultivation on primates in terms of range loss under different expansion scenarios taking into account future demand, oil palm suitability, human accessibility, carbon stock, and primate vulnerability. We found a high overlap between areas of high oil palm suitability and areas of high conservation priority for primates. Overall, we found only a few small areas where oil palm could be cultivated in Africa with a low impact on primates (3.3 Mha, including all areas suitable for oil palm). These results warn that, consistent with the dramatic effects of palm oil cultivation on biodiversity in Southeast Asia, reconciling a large-scale development of oil palm in Africa with primate conservation will be a great challenge

Assessing the potential distribution of insect pests: case studies on large pine weevil (Hylobius abietis L) and horse-chestnut leaf miner (Cameraria ohridella) under present and future climate conditions in European forests†

Forest insect pests represent a serious threat to European forests and their negative effects could be exacerbated by climate change. This paper illustrates how species distribution modelling integrated with host tree species distribution data can be used to assess forest vulnerability to this threat. Two case studies are used: large pine weevil (Hylobius abietis L) and horse-chestnut leaf miner (Cameraria ohridella Deschka & Dimic) both at pan-European level. The proposed approach integrates information from different sources. Occurrence data of insect pests were collected from the Global Biodiversity Information Facility (GBIF), climatic variables for present climate and future scenarios were sourced, respectively, from WorldClim and from the Research Program on Climate Change, Agriculture and Food Security (CCAFS), and distributional data of host tree species were obtained from the European Forest Data Centre (EFDAC), within the Forest Information System for Europe (FISE). The potential habitat of the target pests was calculated using the machine learning algorithm of Maxent model. On the one hand, the results highlight the potential of species distribution modelling as a valuable tool for decision makers. On the other hand, they stress how this approach can be limited by poor pest data availability, emphasizing the need to establish a harmonised open European database of geo-referenced insect pest distribution data. Evaluation de la repartition potentielle des insectes nuisibles: etudes de cas sur le grand charancon du pin (Hylobius abietis L.) et sur la mineuse du marronnier (Cameraria ohridella) dans les conditions climatiques actuelles et futures dans les forets europeennes Les insectes nuisibles des forets representent une menace serieuse pour les forets europeennes et leurs effets negatifs pourraient etre aggraves par le changement climatique. Cet article illustre l'utilisation de la modelisation de la repartition des especes, integree aux donnees de repartition des arbres-hotes, pour evaluer la vulnerabilite des forets a cette menace. Deux etudes de cas sont utilisees, toutes deux au niveau paneuropeen, pour le grand charancon du pin (Hylobius abietis L.) et la mineuse du marronnier (Cameraria ohridella Deschka & Dimic). L'approche proposee utilise des informations de differentes sources. Les donnees sur la presence des insectes nuisibles proviennent du service mondial d'information sur la biodiversite ('Global Biodiversity Information Facility', GBIF), les variables climatiques pour le climat actuel et des scenarios futurs ont ete obtenues, respectivement, a partir de WorldClim et du Programme de recherche sur le changement climatique, l'agriculture et la securite alimentaire (CCAFS), et les donnees sur la repartition des arbres-hotes ont ete obtenues aupres du Centre europeen de donnees sur les forets (EFDAC), qui fait partie du systeme d'information forestiere pour l'Europe ('Forest Information System for Europe', FISE). L'habitat potentiel des ravageurs etudies a ete calcule en utilisant l'algorithme d'apprentissage automatique du modele Maxent. D'une part, les resultats indiquent que la modelisation de la repartition des especes peut devenir un outil precieux pour les decideurs. D'autre part, ils indiquent que cette approche peut etre limitee par le manque de donnees sur les organismes nuisibles, renforcant ainsi la necessite de creer une base de donnees europeenne harmonisee et ouverte pour les donnees geo-referencees sur la repartition des insectes nuisibles. Oцeнкa пoтeнциaльнoгo pacпpocтpaнeния вpeдныx нaceкoмыx нa пpимepe бoльшoгo cocнoвoгo дoлгoнocикa (Hylobius abietis L) и лиcтoвoгo минёpa кoнcкoгo кaштaнa (Cameraria ohridella) пpи cyщecтвyющиx и бyдyщиx климaтичecкиx ycлoвияx в eвpoпeйcкиx лeca

A network approach for managing ecosystem services and improving food and nutrition security on smallholder farms

Smallholder farmers are some of the poorest and most food insecure people on Earth. Their high nutritional and economic reliance on home-grown produce makes them particularly vulnerable to environmental stressors such as pollinator loss or climate change which threaten agricultural productivity. Improving smallholder agriculture in a way that is environmentally sustainable and resilient to climate change is a key challenge of the 21st century. Ecological intensification, whereby ecosystem services are managed to increase agricultural productivity, is a promising solution for smallholders. However, smallholder farms are complex socio-ecological systems with a range of social, ecological and environmental factors interacting to influence ecosystem service provisioning. To truly understand the functioning of a smallholder farm and identify the most effective management options to support household food and nutrition security, a holistic, systems-based understanding is required. In this paper, we propose a network approach to understand, visualise and model the complex interactions occurring among wild species, crops and people on smallholder farms. Specifically, we demonstrate how networks may be used to (a) identify wild species with a key role in supporting, delivering or increasing the resilience of an ecosystem service; (b) quantify the value of an ecosystem service in a way that is relevant to the food and nutrition security of smallholders; and (c) understand the social interactions that influence the management of shared ecosystem services. Using a case study based on data from rural Nepal, we demonstrate how this framework can be used to connect wild plants, pollinators and crops to key nutrients consumed by humans. This allows us to quantify the nutritional value of an ecosystem service and identify the wild plants and pollinators involved in its provision, as well as providing a framework to predict the effects of environmental change on human nutrition. Our framework identifies mechanistic links between ecosystem services and the nutrients consumed by smallholder farmers and highlights social factors that may influence the management of these services. Applying this framework to smallholder farms in a range of socio-ecological contexts may provide new, sustainable and equitable solutions to smallholder food and nutrition security. A free Plain Language Summary can be found within the Supporting Information of this article

Toward a Better Understanding of Non-Addicted, Methamphetamine-Using, Men who Have Sex with Men (MSM) in Atlanta

Methamphetamine use has increasingly become linked with sexual risk behaviors among men have sex with men (MSM). Yet, the majority of research has been done with methamphetamine dependent MSM or with samples in which addiction to the substance was not evaluated. Furthermore, research with methamphetamine-using MSM in the Southern U.S. is lacking. In this study, focus groups and in-depth interviews were conducted in order to understand the motives, context, and other facilitators and barriers of methamphetamine use among non-addicted MSM residing in Atlanta. Participants included 30 non-addicted, methamphetamine-using MSM and 16 local mental and public health officials. Findings from the first of this two-phase formative research project will result in the initial development of a community-tested, culturally-specific social marketing campaign and an individual-based intervention based in HIV-testing facilities

Methamphetamine Use, Transmission Risk Behavior and Internet Use Among HIV-Infected Patients in Medical Care, San Francisco, 2008

Methamphetamine use is associated with adverse health outcomes and HIV incidence. Few studies have assessed methamphetamine use, sexual behavior and Internet use among HIV-infected patients. Surveys were administered to a sample of HIV-infected patients seeking medical care in a San Francisco county hospital and university-based clinic. In 2008, 35% of homosexual participants, 26% of heterosexual participants and 11% of female participants reported methamphetamine use in the past year. Of participants, 29% reported using the Internet to find sex partners; Internet-users versus non-Internet-users reported a higher median number of sex partners in 6 months (4 vs. 1), were more likely to report unprotected sex (32 vs. 10%), and higher rates of methamphetamine use in the past 12 months (48 vs. 24%). Given the association among methamphetamine use, increased sex partners and Internet use, the Internet may present a new and effective medium for interventions to reduce methamphetamine-associated sexual risk behavior