The Ecology of New World Rodent Borne Hemorrhagic Fevers

Few, if any, human settlements are free of peridomestic rodent populations. The threat of rodent borne zoonotic diseases has been widely recognized since the bubonic plague outbreaks of the Middle Ages. In the last decades, outbreaks of human disease caused by the rodent borne hemorrhagic fever viruses, the arenaviruses (family Arenaviridae), and the hantaviruses (family Bunyaviridae, genus Hantavirus) have again generated interest in the general public and scientific community regarding the biology of these types of diseases. Recent studies have identified more than 30 new members of these two groups of viruses. Most are associated with rodents in the family Muridae and many are known to be pathogenic. Ongoing studies are investigating aspects of the ecology and systematics of these viruses and their reservoirs. Ecological studies are currently examining modes of transmission between members of the host species, and environmental factors associated with increased frequency of infection. Systematic research is identifying patterns of co-evolution between the viruses and their hosts. The overall goal of these research efforts is develop predictive models that will identify times and places of increased risk and therefore provide an opportunity for risk reduction in these areas. The information resulting from these efforts will benefit individuals who live or work in close proximity to known wild rodent reservoirs and are at risk of contracting rodent borne diseases

Potential mammalian filovirus reservoirs

Centers for Disease Control and Prevention http://www.cdc.gov/ncidod/EID/vol10no12/04-0346.htmEbola and Marburg viruses are maintained in unknown reservoir species; spillover into human populations results in occasional human cases or epidemics. We attempted to narrow the list of possibilities regarding the identity of those reservoir species. We made a series of explicit assumptions about the reservoir: it is a mammal; it supports persistent, largely asymptomatic filovirus infections; its range subsumes that of its associated filovirus; it has coevolved with the virus; it is of small body size; and it is not a species that is commensal with humans. Under these assumptions, we developed priority lists of mammal clades that coincide distributionally with filovirus outbreak distributions and compared these lists with those mammal taxa that have been tested for filovirus infection in previous epidemiologic studies. Studying the remainder of these taxa may be a fruitful avenue for pursuing the identity of natural reservoirs of filoviruses

Geographic potential for outbreaks of Marburg hemorrhagic fever

Am. J. Trop. Med. Hyg., 75(1), 2006, pp. 9–15 Copyright © 2006 by The American Society of Tropical Medicine and Hygiene 9 http://www.ajtmh.org/cgi/content/abstract/75/1/9Marburg virus represents one of the least well-known of the hemorrhagic fever-causing viruses worldwide; in particular, its geographic potential in Africa remains quite mysterious. Ecologic niche modeling was used to explore the geographic and ecologic potential of Marburg virus in Africa. Model results permitted a reinterpretation of the geographic point of infection in the initiation of the 1975 cases in Zimbabwe, and also anticipated the potential for cases in Angola, where a large outbreak recently (2004–2005) occurred. The geographic potential for additional outbreaks is outlined, including in several countries in which the virus is not known. Overall, results demonstrate that ecologic niche modeling can be a powerful tool in understanding geographic distributions of species and other biologic phenomena such as zoonotic disease transmission from natural reservoir populations

The Importance of Mammalogy, Infectious Disease Research, and Biosafety in the Field

Large amounts of data and multitudes of publications have been independently generated by researchers in mammalogy and infectious diseases. The frequent confluence of these fields in epidemiological research as well as the facility of the data generated to be used in applied methods (e.g., conservation, public outreach, public health interventions) suggests that the intersection of these fields is important not only to their committed scientists but also to other areas of investigation, including public health. Given the increased frequency with which researchers in these fields interact with potentially infected humans, animals, and tissues, their occupations present a higher risk of exposure to a variety of pathogens than those in other fields of biology or among most jobs of the general public. However, a variety of methods are available for minimizing this risk, including increasing awareness of potential risks, using medical prophylaxes (when available), properly employing personal protective equipment, and using adequate disinfectants. Although instances of serious illness from zoonotic diseases among field researchers may be uncommon, they do occur; the purpose of this document is to increase awareness of risks that researchers—principal investigators and students alike—face and highlight steps and resources that can mitigate those risks

The Importance of Mammalogy, Infectious Disease Research, and Biosafety in the Field

Large amounts of data and multitudes of publications have been independently generated by researchers in mammalogy and infectious diseases. The frequent confluence of these fields in epidemiological research as well as the facility of the data generated to be used in applied methods (e.g., conservation, public outreach, public health interventions) suggests that the intersection of these fields is important not only to their committed scientists but also to other areas of investigation, including public health. Given the increased frequency with which researchers in these fields interact with potentially infected humans, animals, and tissues, their occupations present a higher risk of exposure to a variety of pathogens than those in other fields of biology or among most jobs of the general public. However, a variety of methods are available for minimizing this risk, including increasing awareness of potential risks, using medical prophylaxes (when available), properly employing personal protective equipment, and using adequate disinfectants. Although instances of serious illness from zoonotic diseases among field researchers may be uncommon, they do occur; the purpose of this document is to increase awareness of risks that researchers—principal investigators and students alike—face and highlight steps and resources that can mitigate those risks

Effects of georeferencing effort on mapping monkeypox case distributions and transmission risk

<p>Abstract</p> <p>Background</p> <p>Maps of disease occurrences and GIS-based models of disease transmission risk are increasingly common, and both rely on georeferenced diseases data. Automated methods for georeferencing disease data have been widely studied for developed countries with rich sources of geographic referenced data. However, the transferability of these methods to countries without comparable geographic reference data, particularly when working with historical disease data, has not been as widely studied. Historically, precise geographic information about where individual cases occur has been collected and stored verbally, identifying specific locations using place names. Georeferencing historic data is challenging however, because it is difficult to find appropriate geographic reference data to match the place names to. Here, we assess the degree of care and research invested in converting textual descriptions of disease occurrence locations to numerical grid coordinates (latitude and longitude). Specifically, we develop three datasets from the same, original monkeypox disease occurrence data, with varying levels of care and effort: the first based on an automated web-service, the second improving on the first by reference to additional maps and digital gazetteers, and the third improving still more based on extensive consultation of legacy surveillance records that provided considerable additional information about each case. To illustrate the implications of these seemingly subtle improvements in data quality, we develop ecological niche models and predictive maps of monkeypox transmission risk based on each of the three occurrence data sets.</p> <p>Results</p> <p>We found macrogeographic variations in ecological niche models depending on the type of georeferencing method used. Less-careful georeferencing identified much smaller areas as having potential for monkeypox transmission in the Sahel region, as well as around the rim of the Congo Basin. These results have implications for mapping efforts, as each higher level of georeferencing precision required considerably greater time investment.</p> <p>Conclusions</p> <p>The importance of careful georeferencing cannot be overlooked, despite it being a time- and labor-intensive process. Investment in archival storage of primary disease-occurrence data is merited, and improved digital gazetteers are needed to support public health mapping activities, particularly in developing countries, where maps and geographic information may be sparse.</p

Ecology and Geography of Human Monkeypox Case Occurences Across Africa

This is the published version. The original is available from http://www.jwildlifedis.org/content/48/2/335.full.pdf+htmlAs ecologic niche modeling (ENM) evolves as a tool in spatial epidemiology and public health, selection of the most appropriate and informative environmental data sets becomes increasingly important. Here, we build on a previous ENM analysis of the potential distribution of human monkeypox in Africa by refining georeferencing criteria and using more-diverse environmental data to identify environmental parameters contributing to monkeypox distributional ecology. Significant environmental variables include annual precipitation, several temperature-related variables, primary productivity, evapotranspiration, soil moisture, and pH. The potential distribution identified with this set of variables was broader than that identified in previous analyses but does not include areas recently found to hold monkeypox in southern Sudan. Our results emphasize the importance of selecting the most appropriate and informative environmental data sets for ENM analyses in pathogen transmission mapping

Mapping Monkeypox Transmission Risk through Time and Space in the Congo Basin

Monkeypox is a major public health concern in the Congo Basin area, with changing patterns of human case occurrences reported in recent years. Whether this trend results from better surveillance and detection methods, reduced proportions of vaccinated vs. non-vaccinated human populations, or changing environmental conditions remains unclear. Our objective is to examine potential correlations between environment and transmission of monkeypox events in the Congo Basin. We created ecological niche models based on human cases reported in the Congo Basin by the World Health Organization at the end of the smallpox eradication campaign, in relation to remotely-sensed Normalized Difference Vegetation Index datasets from the same time period. These models predicted independent spatial subsets of monkeypox occurrences with high confidence; models were then projected onto parallel environmental datasets for the 2000s to create present-day monkeypox suitability maps. Recent trends in human monkeypox infection are associated with broad environmental changes across the Congo Basin. Our results demonstrate that ecological niche models provide useful tools for identification of areas suitable for transmission, even for poorly-known diseases like monkeypox.This research was supported by the National Institutes of Health grant 1R01TW008859-01 ("Sylvatic Reservoirs of Human Monkeypox"). Use of trade, product, or firm names does not imply endorsement by the United States Government. The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention