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

Hantaviruses in the Americas: a growing problem

Hantaviruses (genus Hantavirus , family Bunyaviridae ) are associated with specific rodent hosts, in which they cause a chronic, asymptomatic infection, involving the shedding of infectious virus into the environment in urine, feces, and saliva. Hantaviruses are associated with three subfamilies of murid rodents: (1) The Murinae (old world rats and mice) host viruses that cause hemorrhagic fever with renal syndrome (HFRS) in Asia and Europe; (2) the Sigmodontinae (New World rats and mice) host viruses that cause hantavirus pulmonary syndrome (HPS) in the Americas; (3) the Arvicolinae (pan-arctic voles and lemmings) host viruses causing mild HFRS in Europe and Asia, but no disease in the Americas

El Clima, los Roedores y la Enfermedad: ¿Es Posible el Pronóstico?

La epidemiología del síndrome pulmonar por hantavirus está estrechamente ligada a la ecología de las poblaciones de roedores portadores de los hantavirus. Nuestros estudios a corto y largo plazo en el oeste de los Estados Unidos han ofrecido un nivel de comprensión más profundo de la dinámica de la infección por el virus Sin Nombre en su huésped natural, el ratón silvestre ( Peromyscus maniculatus ). El riesgo a los humanos está relacionado a la densidad poblacional de los roedores

Ecologic and geographic distribution of filovirus disease

Centers for Disease Control and Prevention http://www.cdc.gov/ncidod/EID/vol10no1/03-0125.htmWe used ecologic niche modeling of outbreaks and sporadic cases of filovirus-associated hemorrhagic fever (HF) to provide a large-scale perspective on the geographic and ecologic distributions of Ebola and Marburg viruses. We predicted that filovirus would occur across the Afrotropics: Ebola HF in the humid rain forests of central and western Africa, and Marburg HF in the drier and more open areas of central and eastern Africa. Most of the predicted geographic extent of Ebola HF appear to have been observed; Marburg HF has the potential to occur farther south and east. Ecologic conditions appropriate for Ebola HF are also present in Southeast Asia and the Philippines, where Ebola Reston is hypothesized to be distributed. This first large-scale ecologic analysis provides a framework for a more informed search for taxa that could constitute the natural reservoir for this virus family

Long-term studies of hantavirus reservoir populations in the southwestern United States: a synthesis.

A series of intensive, longitudinal, mark-recapture studies of hantavirus infection dynamics in reservoir populations in the southwestern United States indicates consistent patterns as well as important differences among sites and host-virus associations. All studies found a higher prevalence of infection in older (particularly male) mice; one study associated wounds with seropositivity. These findings are consistent with horizontal transmission and transmission through fighting between adult male rodents. Despite very low rodent densities at some sites, low-level hantavirus infection continued, perhaps because of persistent infection in a few long-lived rodents or periodic reintroduction of virus from neighboring populations. Prevalence of hantavirus antibody showed seasonal and multiyear patterns that suggested a delayed density-dependent relationship between prevalence and population density. Clear differences in population dynamics and patterns of infection among sites, sampling periods, and host species underscore the importance of replication and continuity of long-term reservoir studies. Nevertheless, the measurable associations between environmental variables, reservoir population density, rates of virus transmission, and prevalence of infection in host populations may improve our capacity to model processes influencing infection and predict increased risk for hantavirus transmission to humans

Emerging Roles of Glycogen Synthase Kinase 3 in the Treatment of Brain Tumors

The constitutively active protein glycogen synthase kinase 3 (GSK3), a serine/threonine kinase, acts paradoxically as a tumor suppressor in some cancers while potentiates growth in others. Deciphering what governs its actions is vital for understanding many pathological conditions, including brain cancer. What are seemingly disparate roles of GSK3 stems from the complex regulation of many cellular functions by GSK3. This review focuses on the regulation of GSK3, its role in survival, apoptosis and DNA damage, and finally its potential therapeutic impact in brain cancer. A thorough understanding of this versatile protein is critical for improving the outcome of various diseases, especially cancer

Long-term studies of hantavirus reservoir populations in the southwestern United States: rationale, potential, and methods.

Hantaviruses are rodent-borne zoonotic agents that cause hemorrhagic fever with renal syndrome in Asia and Europe and hantavirus pulmonary syndrome (HPS) in North and South America. The epidemiology of human diseases caused by these viruses is tied to the ecology of the rodent hosts, and effective control and prevention relies on a through understanding of host ecology. After the 1993 HPS outbreak in the southwestern United States, the Centers for Disease Control and Prevention initiated long-term studies of the temporal dynamics of hantavirus infection in host populations. These studies, which used mark-recapture techniques on 24 trapping webs at nine sites in the southwestern United States, were designed to monitor changes in reservoir population densities and in the prevalence and incidence of infection; quantify environmental factors associated with these changes; and when linked to surveillance databases for HPS, lead to predictive models of human risk to be used in the design and implementation of control and prevention measures for human hantavirus disease

Oliveros Virus: A Novel Arenavirus from Argentina

AbstractDuring the past few decades several newly recognized rodent-borne arenaviruses have been shown to be associated with severe hemorrhagic fever cases in South America. Changes in ecology and farming practices throughout the region have increased the concern over the potential public health threat posed by such emerging virus diseases. Oliveros (OLV) virus is a recently discovered arenavirus of the rodentBolomys obscurusin Argentina. Genetic analysis of the small genomic RNA segment, which encodes the nucleocapsid protein and the envelope glycoproteins, shows that Oliveros is a novel, phylogenetically distinct member of theArenaviridaefamily which differs in nucleotide sequence from the previously characterized members by approximately 35% or more. Despite this level of diversity, OLV virus possesses the same ambisense genome structure and many overall RNA and protein features in common with other arenaviruses. These data represent an important first step in the development of specific immunological and PCR diagnostic reagents to allow assessment of the prevalence and disease potential of this virus

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