Reproduction and nutritional stress are risk factors for Hendra virus infection in little red flying foxes (Pteropus scapulatus).

Hendra virus (HeV) is a lethal paramyxovirus which emerged in humans in 1994. Poor understanding of HeV dynamics in Pteropus spp. (flying fox or fruit bat) reservoir hosts has limited our ability to determine factors driving its emergence.

Henipavirus susceptibility to environmental variables.

The routes of henipavirus transmission between hosts are poorly understood. The purpose of this study was to measure the persistence of henipaviruses under various environmental conditions and thereby gain an insight into likely mechanisms of transmission. Henipaviruses survived for more than 4 days at 22 degrees C in pH-neutral fruit bat urine but were sensitive to higher temperatures and pH changes.

Genetic influences on mosquito feeding behavior and the emergence of zoonotic pathogens.

The feeding behavior of vectors influences the likelihood of pathogen invasion and the exposure of humans to vector-borne zoonotic pathogens. We used multilocus microsatellite genetic typing of an introduced mosquito vector and DNA sequencing of mosquito blood meals to determine the impact of hybrid ancestry on feeding behavior and the emergence of West Nile virus (WNV). The probability of ancestry of Culex pipiens mosquitoes from two bionomically divergent forms, form molestus and form pipiens, influenced the probability that they fed on humans but did not explain a late summer feeding shift from birds to humans.

Collaborative research approaches to the role of wildlife in zoonotic disease emergence.

Emerging infectious diseases are a key threat to public health and the majority are caused by zoonotic pathogens. Here we discuss new collaborative approaches to understanding the process of zoonotic disease emergence that link veterinary medicine, public health, and ecological approaches: conservation medicine and one health. We demonstrate how studies on the underlying drivers of disease emergence (bushmeat hunting, wildlife trade, and deforestation) can provide ways to model, predict, and ultimately prevent zoonotic disease emergence and spread.

Henipaviruses: emerging paramyxoviruses associated with fruit bats.

Two related, novel, zoonotic paramyxoviruses have been described recently. Hendra virus was first reported in horses and thence humans in Australia in 1994; Nipah virus was first reported in pigs and thence humans in Malaysia in 1998. Human cases of Nipah virus infection, apparently unassociated with infection in livestock, have been reported in Bangladesh since 2001.

Review of bats and SARS.

Bats have been identified as a natural reservoir for an increasing number of emerging zoonotic viruses, including henipaviruses and variants of rabies viruses. Recently, we and another group independently identified several horseshoe bat species (genus Rhinolophus) as the reservoir host for a large number of viruses that have a close genetic relationship with the coronavirus associated with severe acute respiratory syndrome (SARS). Our current research focused on the identification of the reservoir species for the progenitor virus of the SARS coronaviruses responsible for outbreaks during 2002-2003 and 2003-2004.

Emerging viruses: coming in on a wrinkled wing and a prayer.

The role that bats have played in the emergence of several new infectious diseases has been under review. Bats have been identified as the reservoir hosts of newly emergent viruses such as Nipah virus, Hendra virus, and severe acute respiratory syndrome-like coronaviruses. This article expands on recent findings about bats and viruses and their relevance to human infections.

Predicting the global spread of H5N1 avian influenza.

The spread of highly pathogenic H5N1 avian influenza into Asia, Europe, and Africa has resulted in enormous impacts on the poultry industry and presents an important threat to human health. The pathways by which the virus has and will spread between countries have been debated extensively, but have yet to be analyzed comprehensively and quantitatively. We integrated data on phylogenetic relationships of virus isolates, migratory bird movements, and trade in poultry and wild birds to determine the pathway for 52 individual introduction events into countries and predict future spread.

Host heterogeneity dominates West Nile virus transmission.

Heterogeneity in host populations and communities can have large effects on the transmission and control of a pathogen. In extreme cases, a few individuals give rise to the majority of secondary infections, which have been termed super spreading events. Here, we show that transmission of West Nile virus (WNV) is dominated by extreme heterogeneity in the host community, resulting in highly inflated reproductive ratios.

Predicting pathogen introduction: West Nile virus spread to Galáipagos.

Emerging infectious diseases are a key threat to conservation and public health, yet predicting and preventing their emergence is notoriously difficult. We devised a predictive model for the introduction of a zoonotic vector-borne pathogen by considering each of the pathways by which it may be introduced to a new area and comparing the relative risk of each pathway. This framework is an adaptation of pest introduction models and estimates the number of infectious individuals arriving in a location and the duration of their infectivity.

Emerging henipaviruses and flying foxes - Conservation and management perspectives.

Wildlife populations are affected by a series of emerging diseases, some of which pose a significant threat to their conservation. They can also be reservoirs of pathogens that threaten domestic animal and human health. In this paper, we review the ecology of two viruses that have caused significant disease in domestic animals and humans and are carried by wild fruit bats in Asia and Australia.

Emerging infectious diseases of plants: pathogen pollution, climate change and agrotechnology drivers.

Emerging infectious diseases (EIDs) pose threats to conservation and public health. Here, we apply the definition of EIDs used in the medical and veterinary fields to botany and highlight a series of emerging plant diseases. We include EIDs of cultivated and wild plants, some of which are of significant conservation concern.

West Nile virus epidemics in North America are driven by shifts in mosquito feeding behavior.

West Nile virus (WNV) has caused repeated large-scale human epidemics in North America since it was first detected in 1999 and is now the dominant vector-borne disease in this continent. Understanding the factors that determine the intensity of the spillover of this zoonotic pathogen from birds to humans (via mosquitoes) is a prerequisite for predicting and preventing human epidemics. We integrated mosquito feeding behavior with data on the population dynamics and WNV epidemiology of mosquitoes, birds, and humans.

Bushmeat hunting, deforestation, and prediction of zoonoses emergence.

Understanding the emergence of new zoonotic agents requires knowledge of pathogen biodiversity in wildlife, human-wildlife interactions, anthropogenic pressures on wildlife populations, and changes in society and human behavior. We discuss an interdisciplinary approach combining virology, wildlife biology, disease ecology, and anthropology that enables better understanding of how deforestation and associated hunting leads to the emergence of novel zoonotic pathogens.

Nipah virus: impact, origins, and causes of emergence.

Nipah virus is an emerging zoonotic pathogen that causes severe febrile encephalitis resulting in death in 40% to 75% of human cases. Nipah virus is considered a biosafety level-4 pathogen and is listed as a select agent with high risk for public health and security due to its high mortality rate in people and the lack of effective vaccines or therapies. The natural reservoir for Nipah virus and related members of the genus Henipavirus are fruit bats of the genus Pteropus.

The ecology of emerging neurotropic viruses.

The authors review common themes in the ecology of emerging viruses that cause neurological disease. Three issues emerge. First, 49% of emerging viruses are characterized by encephalitis or serious neurological clinical symptoms.

Bats are natural reservoirs of SARS-like coronaviruses.

Severe acute respiratory syndrome (SARS) emerged in 2002 to 2003 in southern China. The origin of its etiological agent, the SARS coronavirus (SARS-CoV), remains elusive. Here we report that species of bats are a natural host of coronaviruses closely related to those responsible for the SARS outbreak.