Viruses of pet fish.

Investigation of a fish kill should begin with water quality analysis and use of standard necropsy techniques to rule out the role of parasites or bacteria. The presence of a virus does not mean necessarily that it is a pathogen. Another point to consider is the potential influence of water temperature on pathogenicity; this may be an important factor in developing disease. A list of laboratories that is approved by the USDA to conduct diagnostic testing of aquaculture species can be found at: http://www.aphis.usda.gov/vs/nvsl/labcertification/aquaapplab.htm.     

Viruses and virus diseases of marine mammals.

Poxvirus and several serotypes of calicivirus cause recognizable disease in marine mammals. Pox lesions in pinnipeds are raised and proliferative and are seen most frequently after confinement in captivity. In cetaceans, a poxvirus is associated with a much more benign and chronic lesion called a "tattoo." Numerous caliciviruses of differing antigenic types have been isolated from vesicular lesions and aborted fetuses of northern fur seals and California sea lions as well as from clinically normal and orphaned northern elephant seal pups. An adenovirus has been isolated from a sei whale and an enterovirus has been isolated from a gray whale.     

Viruses as vectors

Traditional vaccines against diseases caused by viruses are based on live attenuated viruses or killed virus preparations. Through the application of molecular biology it is now possible to consider several new approaches to making vaccines, which may combine increased efficacy with greater safety. One of these approaches is to manipulate genetically a virus so that it carries and expresses a foreign gene (or part of a gene) which codes for a protective antigen for another disease. Adeno-, polio- and herpesviruses have been engineered to act as vectors in this way but vaccinia virus remains the main candidate for a recombinant virus vector for vaccine use. The broad host-range of vaccinia virus has made it an effective vector for the analysis of expression of "foreign" antigens as well as a tool for the dissection of the host animal's immune system. For practical purposes in veterinary vaccines, recombinant viruses based on other poxviruses, with more restricted host-ranges, may have certain advantages. Work on the development of recombinant avipoxviruses and capripoxviruses as prototype vaccines for use in poultry and ruminants, respectively, is discussed and illustrated.     

Viruses of waterfowl

Viral disease can cause substantial mortality in wild populations of ducks as well as domesticated geese and ducks. Migrating and captive waterfowl play a role in the dynamics and epidemiology of some viruses that also infect humans, such as influenza virus and West Nile virus. Crowded farm conditions favor the transmission of infectious disease agents among birds. Disease transmission is further facilitated by the comingling of wild anatids with nonmigratory resident waterfowl flocks in zoological parks or on farms. The following article will emphasize the most important viral diseases of waterfowl and briefly cover the newer diseases of suspected viral etiology in this group of birds. As viral detection and identification techniques become more and more sophisticated, and as the study of wildlife diseases increases, new viruses will be discovered and new diseases will be encountered. More research into the viral diseases of waterfowl is needed; the implementation of the latest techniques in molecular epidemiology in addition to the “gold standard” techniques such as virus isolation and histopathology, will yield insight into how viruses move from species to species and from region to region.     

Viruses in reptiles

ABSTRACT: The etiology of reptilian viral diseases can be attributed to a wide range of viruses occurring across different genera and families. Thirty to forty years ago, studies of viruses in reptiles focused mainly on the zoonotic potential of arboviruses in reptiles and much effort went into surveys and challenge trials of a range of reptiles with eastern and western equine encephalitis as well as Japanese encephalitis viruses. In the past decade, outbreaks of infection with West Nile virus in human populations and in farmed alligators in the USA has seen the research emphasis placed on the issue of reptiles, particularly crocodiles and alligators, being susceptible to, and reservoirs for, this serious zoonotic disease. Although there are many recognised reptilian viruses, the evidence for those being primary pathogens is relatively limited. Transmission studies establishing pathogenicity and cofactors are likewise scarce, possibly due to the relatively low commercial importance of reptiles, difficulties with the availability of animals and permits for statistically sound experiments, difficulties with housing of reptiles in an experimental setting or the inability to propagate some viruses in cell culture to sufficient titres for transmission studies. Viruses as causes of direct loss of threatened species, such as the chelonid fibropapilloma associated herpesvirus and ranaviruses in farmed and wild tortoises and turtles, have re-focused attention back to the characterisation of the viruses as well as diagnosis and pathogenesis in the host itself.1. Introduction2. Methods for working with reptilian viruses3. Reptilian viruses described by virus families3.1. Herpesviridae3.2. Iridoviridae3.2.1 Ranavirus3.2.2 Erythrocytic virus3.2.3 Iridovirus3.3. Poxviridae3.4. Adenoviridae3.5. Papillomaviridae3.6. Parvoviridae3.7. Reoviridae3.8. Retroviridae and inclusion body disease of Boid snakes3.9. Arboviruses3.9.1. Flaviviridae3.9.2. Togaviridae3.10. Caliciviridae3.11. Picornaviridae3.12. Paramyxoviridae4. Summary5. Acknowledgements6. Competing interests7. References.     

Viruses of Lower Vertebrates

Viruses of lower vertebrates recently became a field of interest to the public due to increasing epizootics and economic losses of poikilothermic animals. These were reported worldwide from both wildlife and collections of aquatic poikilothermic animals. Several RNA and DNA viruses infecting fish, amphibians and reptiles have been studied intensively during the last 20 years. Many of these viruses induce diseases resulting in important economic losses of lower vertebrates, especially in fish aquaculture. In addition, some of the DNA viruses seem to be emerging pathogens involved in the worldwide decline in wildlife. Irido‐, herpes‐ and polyomavirus infections may be involved in the reduction in the numbers of endangered amphibian and reptile species. In this context the knowledge of several important RNA viruses such as orthomyxo‐, paramyxo‐, rhabdo‐, retro‐, corona‐, calici‐, toga‐, picorna‐, noda‐, reo‐ and birnaviruses, and DNA viruses such as parvo‐, irido‐, herpes‐, adeno‐, polyoma‐ and poxviruses, is described in this review.     

Viruses of lower vertebrates

Viruses of lower vertebrates recently became a field of interest to the public due to increasing epizootics and economic losses of poikilothermic animals. These were reported worldwide from both wildlife and collections of aquatic poikilothermic animals. Several RNA and DNA viruses infecting fish, amphibians and reptiles have been studied intensively during the last 20 years. Many of these viruses induce diseases resulting in important economic losses of lower vertebrates, especially in fish aquaculture. In addition, some of the DNA viruses seem to be emerging pathogens involved in the worldwide decline in wildlife. Irido-, herpes- and polyomavirus infections may be involved in the reduction in the numbers of endangered amphibian and reptile species. In this context the knowledge of several important RNA viruses such as orthomyxo-, paramyxo-, rhabdo-, retro-, corona-, calici-, toga-, picorna-, noda-, reo- and birnaviruses, and DNA viruses such as parvo-, irido-, herpes-, adeno-, polyoma- and poxviruses, is described in this review.     

负链RNA病毒的反向遗传技术

反向遗传技术是一种新的分子生物学技术,它在深入研究负链RNA病毒基因组结构和功能,探寻其基因组复制、转录和研发新型基因工程疫苗上发挥着重要的作用。文章介绍了分节与不分节负链RNA病毒的复制机理和特征,论述了反向遗传学在研究这些病毒上的策略、最新研究进展及其主要影响拯救效率的因素,进一步涉及了负链RNA病毒载体及其重组病毒的研究动态。因此,通过反向遗传学,人们将更加了解负链RNA病毒,为科学利用和有效控制该病毒奠定基础。