Vector For Spread Research Articles

Challenges associated with pre-border management of biofouling on oil rigs

The potential for oil rigs to transport diverse, reef-like communities around the globe makes them high risk vectors for the inadvertent spread of non-indigenous species (NIS). This paper describes two case studies where a suite of pre-border management approaches was applied to semi-submersible drilling rigs. In the first case study, a drilling rig was defouled in-water prior to departure from New Zealand to Australia. Risk mitigation measures were successful in reducing biosecurity risks to the recipient region, but they resulted in the unintentional introduction of the non-indigenous brown mussel (Perna perna) to New Zealand when the rig was defouled in-water by divers. In the second case study, lessons learned from this high-profile incursion resulted in a more structured approach to pre-border management, and this serves as a useful template for future rig transfers.

Aerosol influenza transmission risk contours: A study of humid tropics versus winter temperate zone

BackgroundIn recent years, much attention has been given to the spread of influenza around the world. With the continuing human outbreak of H5N1 beginning in 2003 and the H1N1 pandemic in 2009, focus on influenza and other respiratory viruses has been increased. It has been accepted for decades that international travel via jet aircraft is a major vector for global spread of influenza, and epidemiological differences between tropical and temperate regions observed. Thus we wanted to study how indoor environmental conditions (enclosed locations) in the tropics and winter temperate zones contribute to the aerosol spread of influenza by travelers. To this end, a survey consisting of 632 readings of temperature (T) versus relative humidity (RH) in 389 different enclosed locations air travelers are likely to visit in 8 tropical nations were compared to 102 such readings in 2 Australian cities, including ground transport, hotels, shops, offices and other publicly accessible locations, along with 586 time course readings from aircraft.ResultsAn influenza transmission risk contour map was developed for T versus RH. Empirical equations were created for estimating: 1. risk relative to temperature and RH, and 2. time parameterized influenza transmission risk. Using the transmission risk contours and equations, transmission risk for each country's locations was compared with influenza reports from the countries. Higher risk enclosed locations in the tropics included new automobile transport, luxury buses, luxury hotels, and bank branches. Most temperate locations were high risk.ConclusionEnvironmental control is recommended for public health mitigation focused on higher risk enclosed locations. Public health can make use of the methods developed to track potential vulnerability to aerosol influenza. The methods presented can also be used in influenza modeling. Accounting for differential aerosol transmission using T and RH can potentially explain anomalies of influenza epidemiology in addition to seasonality in temperate climates.

Journey to the heart of macrophages: the delicate relationship between HIV-1 and a multifaceted cell type

Cells of the monocyte-macrophage lineage play multiple roles during the infection of primate lentiviruses serving as reservoirs for viral production or as vectors for viral spread to other cells and tissues. The human immunodeficiency type I virus is not only capable of establishing such complex and dynamic relations with this cell type, but is also able to modulate their physiology and behavior, thus shaping ensuing cellular immune responses. In this issue of Retrovirology, a series of reviews explores the multiple manners in which the virus and cells belonging to the monocyte-macrophage lineage interact and affect each other.

Regional connectivity and coastal expansion: differentiating pre‐border and post‐border vectors for the invasive tunicate Styela clava

The dramatic increase in marine bio-invasions, particularly of non-indigenous ascidians, has highlighted the vulnerability of marine ecosystems and the productive sectors that rely on them. A critical issue in managing invasive species is determining the relative roles of ongoing introductions, versus the local movement of propagules from established source populations. Styela clava (Herdman, 1882), the Asian clubbed tunicate, once restricted to the Pacific shores of Asia and Russia, is now abundant throughout the northern and southern hemispheres and has had significant economic impact in at least one site of incursion. In 2005 S. clava was identified in New Zealand. The recent introduction of this species, coupled with its restricted distribution, provided an ideal model to compare and contrast the introduction and expansion process. In this study, the mitochondrial DNA cytochrome oxidase subunit I gene (COI) gene and 11 microsatellite markers were used to test the regional genetic structure and diversity of 318 S. clava individuals from 10 populations within New Zealand. Both markers showed significant differentiation between the northern and southern populations, indicative of minimal pre- or post-border connectivity. Additional statistics further support pre- and post-border differentiation among Port and Harbour populations (i.e. marinas and aquaculture farms). We conclude that New Zealand receives multiple introductions, and that the primary vector for pre-border incursions and post-border spread is most likely the extensive influx of recreational vessels that enter northern marinas independent of the Port. This is a timely reminder of the potential for hull-fouling organisms to expand their range as climates change and open new pathways.

Domestic ballast operations on the Great Lakes: potential importance of Lakers as a vector for introduction and spread of nonindigenous species

Ballast water is recognized globally as a major vector of aquatic nonindigenous species (NIS) introductions; domestic ballast water transfers, however, have generally been considered low risk in North America. We characterize ballast operations of domestic ships in the Great Lakes – St. Lawrence River system (Lakers) during 2005–2007 to examine the risk of primary and secondary introductions associated with ballast water transfers over short distances. Results indicate that Lakers transported at least 68 million tonnes of ballast water annually. Approximately 71% of ballast water transfers were interregional, with net movement being from lower to upper lakes. A small proportion of ballast water discharged in the Great Lakes (<1%) originated from ports in the St. Lawrence River that may serve as sources for new NIS. These results indicate that domestic ballast water transfers may contribute to NIS introductions and are likely the most important ballast-mediated pathway of secondary spread within the Great Lakes. Future efforts to reduce invasion impacts should consider both primary and secondary introduction mechanisms.

Influenza Vaccine: Protecting Children Protects Everyone

Some data suggest that children are important vectors in the spread of seasonal influenza. In a cluster-randomized double-blind study, investigators examined whether immunizing children (age range, 3–15 years) against influenza protects the whole community. This study was conducted in Hutterite …

First confirmed records of the non-native amphipod Caprella mutica (Schurin 1935) along the coast of British Columbia, Canada, and the potential for secondary spread via hull fouling

Here, we report the first records of the non-native amphipod Caprella mutica along the coast of British Columbia, Canada. Between 2006 and 2009, we surveyed marine fouling communities across 81 subtidal sites, and sampled hulls and sea-chests from 18 domestically operated commercial vessels. Caprella mutica was present at 33% of the sites and on 22% of the vessels, sometimes at remarkably high densities (>10,000 individuals m -2 ). Our findings confirm an extensive distribution of C. mutica along the coast of the northeast Pacific, and offer additional evidence in support of hull fouling as an important vector for secondary spread.

A Succesful Treatment of Avian Influenza Infection in Turkey

Avian influenza is a disease characterized with severe pneumonia caused by virus influenza A. Birds and poultry are vectors for spread of this disease. It is diagnosed by clinical evidence and reverse transcription-polymerase chain reaction. Here, we discuss the treatment procedures of a child diagnosed as avian influenza.

Wetlands as barriers: effects of vegetated waterways on downstream dispersal of zebra mussels

Summary1. Stream flow is a major vector for zebra mussel spread among inland lakes. Veligers have been found tens to hundreds of km from upstream source lakes in unvegetated stream and river systems. It has been suggested, however, that the downstream transport of zebra mussels is restricted by wetland ecosystems. We hypothesized that vegetated waterways, (i.e. wetland streams) would hinder the downstream dispersal of zebra mussels in connected inland lake systems.2. Veliger abundance, recruitment and adult mussels were surveyed in four lake‐wetland systems in southeastern Michigan, U.S.A. from May to August 2006. Sampling was conducted downstream of the lakes invaded by zebra mussels, beginning at the upstream edge of aquatic vegetation and continuing downstream through the wetland streams.3. Veliger abundance decreased rapidly in vegetated waterways compared to previously reported rates of decrease in non‐vegetated streams. Veligers were rarely found more than 1 km downstream from where vegetation began. Newly recruited individuals and adults were extremely rare beyond open water in the wetland systems.4. Densely vegetated aquatic ecosystems limit the dispersal of zebra mussels downstream from invaded sources. Natural, remediated and constructed wetlands may therefore serve as a protective barrier to help prevent the spread of zebra mussels and other aquatic invasive species to other lakes and ecosystems.

Acute Respiratory Infections in a Recently Arrived Traveler to Your Part of the World*

Many acute infectious pulmonary diseases have incubation periods that are long enough for travelers to have symptoms after returning home to a health-care system that is not familiar with “foreign” infections. Respiratory infections have a relatively limited repertoire of clinical manifestations, so that there is often nothing characteristic enough about a specific infection to make the diagnosis obvious. Thus, the pathway to the diagnosis of infections that are not endemic in a region relies heavily on taking a thorough history of both itinerary and of specific exposures. One important caveat is that on occasion, the history of a recent trip creates an element of “tunnel vision” in the evaluating health-care provider. It is tempting to relate a person's problem to that recent trip; however, when evaluating recent returnees, it is always important to remember that the travel may have nothing to do with the patient's presentation. Recent travel may add diagnostic considerations to the list of possibilities, but an astute clinician must not disregard the possibility that the patient's illness has nothing to do with the recent trip.

Potential spread of the invasive plant Hydrilla verticillata in South Africa based on anthropogenic spread and climate suitability

Hydrilla verticillata (L.f.) Royle is a submerged aquatic plant native to Asia and Australia that is highly invasive in the USA and was first recorded in South Africa in 2006. It is only known from one locality, Pongolapoort Dam in KwaZulu-Natal Province, but there are fears that it might spread to other sites. The primary vector of spread in the USA is recreational boaters and anglers. A survey at a fishing competition on Pongolapoort Dam showed that anglers travel considerable distances around South Africa (73% of water bodies were >200 km, visited by 68% of the respondents). A Threat Index for freshwater bodies throughout South Africa visited by participants of the competition was calculated showing that dams in the vicinity of the infestation were more at risk from invasion. Further, the potential distribution of the weed based on climatic matching with the region of origin showed that most of the country was suitable for establishment, with the exception of the high-lying interior of the country. Recommendations for reducing the potential spread of hydrilla in South Africa are presented.

Retropharyngeal Lymph Node Metastasis From Esthesioneuroblastoma: A Review of the Therapeutic and Prognostic Implications

Esthesioneuroblastoma (ENB) is a malignant neoplasm of the olfactory epithelium. Metastasis of ENBs to retropharyngeal lymph nodes is an important finding on imaging examinations that alters staging and treatment. A total of 17 cases of ENB from 3 institutions were evaluated. The CT and MR imaging findings from the cases of 4 patients with ENB with retropharyngeal metastatic disease are reviewed. The vector of spread, staging, and treatment implications are discussed.

Evidence for human‐mediated dispersal of exotic earthworms: support for exploring strategies to limit further spread

As potent ecosystem engineers, non-native earthworms are altering the fundamental structure and function of previously earthworm-free cold-temperate hardwood forests in North America. Discarded earthworms used for fishing bait has been presumed to be an important vector for the continued spread of non-native earthworms because epicentres of invasion often include boat landings, lakeshores and roads. However, controversy has remained about the overall importance of human-mediated spread vs. natural expansion of established earthworm populations. In this issue of Molecular Ecology, Cameron et al. explore the continued role of humans in dispersing non-native earthworms.

Activation of human monocytes after infection by human coronavirus 229E

Human coronaviruses (HCoV) are recognized respiratory pathogens that may be involved in other pathologies such as central nervous system (CNS) diseases. To investigate whether leukocytes could participate in respiratory pathologies and serve as vector for viral spread towards other tissues, the susceptibility of human leukocytic cell lines and peripheral blood mononuclear cells (PBMC) to HCoV-229E and HCoV-OC43 infection was investigated. Human primary monocytes/macrophages were susceptible to HCoV-229E infection, but strongly restricted HCoV-OC43 replication. Moreover, productive HCoV-229E infection of primary monocytes and of the THP-1 monocytic cell line led to their activation, as indicated by the production of pro-inflammatory mediators, including TNF-α, CCL5, CXCL10 and CXCL11 and MMP-9. Moreover, an in vitro chemotaxis assay showed that motility towards chemokines of THP-1 cells and primary monocytes was increased following an acute or persistent HCoV-229E infection. Taken together, these results suggest that infected monocytes could serve as a reservoir for HCoV-229E, become activated, participate in the exacerbation of pulmonary pathologies, as well as serve as potential vectors for viral dissemination to host tissues, where it could be associated with other pathologies.

Modeling the spread of the Emerald Ash Borer

Recently, an invasive Asian beetle known as the Emerald Ash Borer (EAB) ( Agrilus planipennis Coleoptera: Buprestidae) has emerged as a threat to ash trees in the Midwestern United States and Canada [McCullough, D.G., Katovich, S.A., 2004. Pest Alert: Emerald Ash Borer. United States Forest Service, Northeastern Area. NA-PR-02-04]. Significant infestations in Michigan and nearby areas have all but doomed nearly 1 billion native ash trees. However, surrounding regions may still be able to prevent tree damage from occurring at the scale once inflicted by Dutch elm disease in the 1970s. This paper presents an argument for the establishment of a widely accessible knowledgebase of information on the EABs spread capabilities. We argue that spatial dynamic modeling stands as a flexible and powerful decision support system platform. We present initial simulations of EAB spread scenarios constructed using tree information and land use data collected for DuPage County, IL, an uninfected suburban county in the Chicago metropolitan area. These simulations test policies focused on impeding the costly spread of the beetle. This analysis also presents a framework for further studies assessing the economic impacts on municipalities and counties due to tree removal costs and aesthetic damage. Our work points to human driven movement as the major vector for EAB spread throughout our study area. Here, the focus falls on the ability of state and county implemented firewood quarantines to act as effective policies for slowing EAB spread.

Differential shuffling of native genetic diversity across introduced regions in a brown alga: aquaculture vs. maritime traffic effects.

Worldwide marine invaders, such as the brown alga Undaria pinnatifida, offer challenging models for unraveling the apparent paradox of sustainable settlement of exotic species over a large spectrum of environments. Two intergenic noncoding mitochondrial loci were found to be highly informative at the within-species level. Twenty-five haplotypes were found over the whole dataset (333 base pairs, 524 individuals, and 24 populations). The native range showed striking population genetic structure stemming from low diversity within and high differentiation among populations, a pattern not observed in the introduced range of this seaweed. Contrary to classical expectations of founding effects associated with accidental introduction of exotic species, most of the introduced populations showed high genetic diversity. At the regional scale, genetic diversity and sequence divergence showed contrasting patterns in the two main areas of introduction (Europe and Australasia), suggesting different processes of introduction in the two regions. Gene genealogy analyses point to aquaculture as a major vector of introduction and spread in Europe but implicate maritime traffic in promoting recurrent migration events from the native range to Australasia. The multiplicity of processes and genetic signatures associated with the successful invasion confirms that multiple facets of global change, e.g., aquaculture practices, alteration of habitats, and increased traffic, act in synergy at the worldwide level, facilitating successful pandemic introductions.

Airborne Spread of Disease — The Implications for Dentistry

The potential for the airborne spread of disease has been recognized for many years. Recent studies have shown that this mode for disease transmission is capable of spreading a fatal disease such as Severe Acute Respiratory Syndrome over a wide area. Many dental procedures produce extensive aerosols and splatter that are routinely contaminated with bacteria, viruses, and blood. In the past, the potential for these aerosols and splatter to be a vector for disease spread has not been emphasized in dental infection control. Recently published data shows a need to reassess the potential for dental aerosols and splatter to spread disease and the need for their control. Simple and inexpensive methods for the control of dental aerosols and splatter are given. Dental personnel are urged to make the control of aerosols a standard part of their infection control procedures.

The survival of foot-and-mouth disease virus in raw and pasteurized milk and milk products.

The Foot-and-Mouth Disease virus (FMDV) is not a public health threat, but it is highly contagious to cloven-footed animals. The virus is shed into milk up to 33 h before there are apparent signs of the disease in dairy cows, and, in extreme cases, signs of disease may not appear for up to 14 d. During this time, raw milk can serve as a vector for spread of the disease both at the farm and during transport to the processing plant by milk tanker. Raw milk and milk products fed to animals have the potential to cause infection, but the potential for pasteurized milk products to cause infection is largely unknown. Current minimum pasteurization standards may not be adequate to eliminate FMDV in milk completely. The purpose of this paper is to assess the literature on the thermal resistance of FMDV in milk and milk products, to identify the risks associated with ingestion of pasteurized products by animals, and to lay a strategy to prevent the spread of FMDV from contaminated milk.

Fish as vectors in the dispersal of Bythotrephes cederstroemi: diapausing eggs survive passage through the gut

Summary 1 Bythotrephes cederstroemi (Crustacea: Onychopoda: Cercopagidae) is an introduced invertebrate predator currently spreading through the Laurentian Great Lakes region of North America. We examined a previously unsuspected way in which B. cederstroemi may be dispersed by fish by their consumption of diapausing eggs. 2 Ninety-four percentage of the mature B. cederstroemi diapausing eggs consumed by fish were egested apparently intact. This proportion is considerably above previous estimates for the ephippial eggs of Daphnia. The hatching success of diapausing eggs was compared among four categories: (a) eggs released naturally by B. cederstroemi (control, 73% hatched) (b) eggs released during ‘stressful confinement’ (46% hatched) (c) eggs dissected from dead females (13% hatched) and (d) eggs recovered from faecal pellets following consumption by fish (viable gut passage experiment, 41% hatched). 3 Samples of small fish and B. cederstroemi were collected simultaneously. Examination of gut contents revealed that fish contained B. cederstroemi diapausing eggs and that B. cederstroemi bearing resting eggs were consumed selectively over those without eggs. Moreover, fish selected B. cederstroemi bearing mature rather than immature diapausing eggs. 4 The fact that diapausing eggs survive gut passage is important for the dispersal of B. cederstroemi. Fish often move between the pelagic and littoral zones of lakes and may thus disperse diapausing eggs widely. Fish may also move between lakes connected by river systems and can be caught and passively dispersed by anglers or piscivorous birds. Our results demonstrate the potential for fish to act as vectors in the spread of B. cederstroemi.

Comment on D. M. Wilkinson (1997). ‘Plant colonization: are wind dispersed seeds really dispersed by birds at larger spatial and temporal scales?’

(it was probably rightly excluded, owing number of pollen grains counted in each (1997). ‘Plant colonization: are to ‘its water dispersal strategy’ (Wilkinson, spectrum), and so is inherently as inwind dispersed seeds really 1997: 62; but see Chambers & Elliott, 1989)); consistent measure; whereas the ‘rational dispersed by birds at larger spatial whereas had Corylus been excluded (on the limit’ (the rise to higher percentage values) and temporal scales?’ grounds of incomplete separation from Myis still a relative, rather than an absolute,