Alien Pathogens Research Articles

Emerging virus and viroid pathogen species identified for the first time in horticultural plants in Finland in 1997-2010

Expansion and intensification of global trade in horticultural plants has increased the risk of spread of new alien pathogen species in the EU. Alien species of pathogenic viruses and viroids in horticultural plants have been introduced into Finland in infected plant material (plants, seedlings, cuttings, tubers, seeds). By 1997, about 30 virus species of horticultural plants had been detected in Finland. We aimed at compiling emerging new virus and viroid records during 1997-2010. Eight new viruses belonging to tospo-, potex-, poty-, tymo-, ilar- and allexiviruses were detected in horticultural plants: four occurred in greenhouse crops, two in vegetables and two in garden ornamentals outdoors. Five new findings of viroids were made in ornamental and vegetable greenhouse crops during 2008-2009. More rapid and accurate diagnostic methods have contributed to identifying new alien pathogens. Global trade seems to be the main reason for the introduction of the newest virus and viroid pathogens into Finland.;

Examples of alien pathogens in Finnish potato production - their introduction, establishment and consequences

Most pathogens on potato have been imported into Finland via contaminated seed more than hundred years ago. The history of migration and the consequences for potato production of potato wart, blackleg and soft rot, Potato mop-top virus (PMTV) and its vector powdery scab are reviewed as examples of economically important and biologically different potato pathogens. Potato wart spread alarmingly during 1920-1960. Plant quarantine acts and the use of resistant cultivars were successful in eradicating the disease. The pathogens causing blackleg and soft rot increased rapidly in 1960-1970. Development of seed certification schemes after the end of the 1970s decreased disease incidence and made the disease insignificant other than for seed potato production. Introduction of new strains of blackleg bacteria in 2003 caused the disease again to become a considerable threat to potato production. PMTV was imported into Finland in the 1970s where it spread rapidly, especially in starch potato production. Currently it is common in all potato production except that of seed potato. The disease cannot be eradicated but contamination of clean fields can be prevented. New diseases can spread to Finland in future but population changes of existing pathogens have recently caused more problems than species completely new to Finland.;

DNA vaccine protects ornamental koi ( Cyprinus carpio koi) against North American spring viremia of carp virus

The emergence of spring viremia of carp virus (SVCV) in the United States constitutes a potentially serious alien pathogen threat to susceptible fish stocks in North America. A DNA vaccine with an SVCV glycoprotein (G) gene from a North American isolate was constructed. In order to test the vaccine a challenge model utilizing a specific pathogen-free domestic koi stock and a cold water stress treatment was also developed. We have conducted four trial studies demonstrating that the pSGnc DNA vaccine provided protection in vaccinated fish against challenge at low, moderate, and high virus doses of the homologous virus. The protection was significant ( p < 0.05) as compared to fish receiving a mock vaccine construct containing a luciferase reporter gene and to non-vaccinated controls in fish ranging in age from 3 to 14 months. In all trials, the SVCV-G DNA immunized fish were challenged 28-days post-vaccination (546 degree-days) and experienced low mortalities varying from 10 to 50% with relative percent survivals ranging from 50 to 88%. The non-vaccinated controls and mock construct vaccinated fish encountered high cumulative percent mortalities ranging from 70 to 100%. This is the first report of a SVCV DNA vaccine being tested successfully in koi. These experiments prove that the SVCV DNA (pSGnc) vaccine can elicit specific reproducible protection and validates its potential use as a prophylactic vaccine in koi and other vulnerable North American fish stocks.

외래침입 병원체에 의한 작물 병 발생 및 분포

2001년부터 2003년까지 22종의 외래 침입 벼원체들에 의한 작물의 병 발생과 분포를 조사하였다. 조사돈 22종 중 18종은 그들의 기주식물에서 병 발생이 확인되었으나 4종은 병 발생이 확인되지 않았다. 외래 유입 병원체들이 국내로 유입될 당시 학명이 검토되었고, 탄저병균을 포함한 10종의 병원균 학명이 개정되었다. 외래유입병원체들의 기주범위를 조사한 결과, 8종은 유입당시 기술된 기주 뿐만 아니라 다른 작물에서도 병 발생이 확인되었다. Occurrence and distribution of crop diseases caused by invasive alien pathogens were surveyed in Korea from 2001 to 2003. Of 22 species of invasive alien pathogens surveyed, 18 species were found on their host plants but 4 species were not. Scientific names of the alien plant pathogens introduced into Korea in the past were reviewed. Revised scientific names of 10 species including anthracnose pathogens were amended in the list. Host ranges of invasive alien pathogens were investigated. Eight species of the invasive alien pathogens were found on new host plants as well as their host plants recorded in the past.

Robert S Desowitz, Federal bodysnatchers and the New Guinea virus: tales of parasites, people and politics, New York and London, W W Norton, 2002, pp. x, 262, £19.95 (hardback 0-393-05185-4).

Robert S Desowitz, Federal bodysnatchers and the New Guinea virus: tales of parasites, people and politics, New York and London, W W Norton, 2002, pp. x, 262, £19.95 (hardback 0-393-05185-4).

Optic nerve crush: protection and regeneration

In neurodegenerative disorders, as well as in acute central nervous system (CNS) injuries, the initial impairment triggers a cascade of destructive events, collectively termed secondary degeneration, which eventually cause much more extensive damage. To investigate the process of secondary degeneration and ways to prevent it, we designed a well-calibrated model of optic nerve crush injury. Until recently, the main purpose of the immune system was thought to be protection of the body against alien pathogens. Since mechanical or biochemical insults do not involve exogenous pathogens, recruitment of the adaptive immune system was not considered relevant in such cases. We recently demonstrated, however, that a T-cell-mediated immune response directed against self-antigens residing in the site of damage can be beneficial for the injured optic nerve or spinal cord. This protective autoimmune response was found to be spontaneously evoked in some individuals, but not strongly enough to significantly affect recovery. Our aim was to boost this protective response in those individuals capable of spontaneously manifesting it, and to induce it in those incapable of manifesting it spontaneously. Optimal functional recovery requires the application of a proper combination of neuroprotection and neuroregeneration.

Amphibians: suitable candidates for breeding-release programmes

Zoological parks are playing an increasingly important role in the management of threatened species through education, the maintenance of captive gene banks and the reintroduction of captive-bred animals into the wild. This paper discusses the suitability of amphibian species for reintroduction. The important features of amphibians for these programmes are highlighted, i.e., their high fecundity to allow rapid build-up of captive populations coupled with few behavioural problems with captive-bred animals, as well as the low cost of maintenance. The potential problems of inbreeding, poor retention of innate behavioural repertoires after multiple generation captive breeding, and the introduction of alien pathogens into wild populations are considered. Release programmes for two species, the Mallorcan midwife toad Alytes muletensis and the Puerto Rican crested toad Peltophryne lemur, are reviewed.

Processing Foreign Turfgrass Germplasm through Federal Quarantine

Foreign germplasm will continue to be an important component of turfgrass breeding programs. Hundreds of alien pathogens overseas are not found in the USA, and some are responsible for major economically devastating losses. Vegetative propagules, but not imported seeds of turfgrass genera, are quarantined on arrival in the USA. They are closely observed for insects and diseases, and are tested for some 50 viruses reported worldwide to infect grasses. Two virus‐indexing tests are conducted in duplicate under quarantine control 6 to 12 mo apart. They are (i) mechanical transmission of viruses in extracted sap to eight genera of monocots (herbaceous test) such as wheat (Triticum aestivum L.) and corn (Zea mays L.), each of which is sensitive to one or more viruses, and (ii) sap examination under the electron microscope (EM) for the presence of virus particles. More than 95% of the accessions are released from quarantine after completion of 12 to 18 mo of virus testing. Status of quarantined germplasm is maintained in the Germplasm Resources Information Network (GRIN), which any U.S. scientist can access via computer. Processing turfgrass germplasm through quarantine will continue to be an important component of the Federal program of safeguarding exotic germplasm introduction and eventual introgression.

The Onslaught of Alien Species, and Other Challenges in the Coming Decades *

Abstract: Among the many environmental challenges faced by conservation scientists and managers in the coming decades, the inexorable invasion of alien species from distant land masses and between heretofore isolated regions within continents may be the most revolutionary. Although these invasions will homogenize and impoverish the world's biota, they will lead to a deeper understanding of ecological communities. One consequence of the current biotic interchange is that the public's use of the outdoors will continue to decline as new and alien pathogens and parasites, their distributions and survival enhanced by climate warming and other anthropogenic factors, reduce the safety and enjoyment of hunting fishing and hiking. The forthcoming and massive ecological disruptions are bound to produce misunderstanding and conflict among environmentalists. Attempts by conservation biologists to manage wild and feral animals, including vector species, will be blocked by animal's rights groups. Even within the conservation biology movement there are many real and potential conflicts, especially over turf and resources. Such conflicts are a serious threat to biological diversity. Tolerance and compromise are essential if conservation biology is to accomplish its mission.