From:
Sukie Crandall
Date: 2007-10-25 20:05:10 UTC
Subject: [ferrethealth] New work on how CDV jumps across species
To: ferrethealth@yahoogroups.com, ferret-l@LISTSERV.FERRETMAILINGLIST.ORG
http://www.sciencedaily.com/releases/2007/10/071025094914.htm
is a Science Daily (RECOMMENDED RESOURCE!) article on new work about how =
Canine Distemper=20
jumps across species.
Below are a few short segments. Please, see the URL for the full=20
article which contains more than these bare bones of info.
> ScienceDaily (Oct. 25, 2007) =97 Researchers at the University of=20
> Leeds have made a breakthrough in understanding a virus which poses=20
> one of the greatest global disease threats
...
> The discovery of how canine distemper Virus (CDV)1 jumps across and=20
> infects different species of carnivores could lead to a more=20
> effective monitoring and control of the virus.
> Whilst these =91pathogen jumps=92 across species are quite common, very =
> little is known about the process of how viruses takes hold and=20
> become established in new host species.
...
> =93The virus needs to bind to a specific receptor on cells in the=20
> host in order to infect it,=94 explains lead researcher, PhD student=20
> Alex McCarthy, from the University=92s Faculty of Biological=20
> Sciences. =93But the sequences of receptors vary between species, so=20
> a virus from one species shouldn=92t be able recognise and infect the =
> cells of other species.=94
...
> By analysing the virus=92 genetic sequence in both dog and wild=20
> carnivore species, the research team were able to prove that two=20
> key parts of a CDV protein specifically involved in receptor=20
> recognition had evolved during the host jumps, where as the rest of=20
> the protein showed very few changes among viruses from different=20
> species.
...
> The spread and incidences of CDV epidemics are increasing, due to=20
> globalisation and the rise in the domestic and feral dog=20
> populations associated with growing human populations, especially=20
> where these impinge on previously undisturbed habitats.
> =93CDV in wild carnivore populations is usually fatal=94 says McCarthy. =
> =93So as well as the possibility of developing new therapies, the=20
> techniques used in this research offer a way of predicting when=20
> local virus isolates may become capable of causing a full blown=20
> epidemic in species of conservation concern.=94
Related abstract:
> Proc Biol Sci. 2007 Oct 23; [Epub ahead of print]
> Pathogen evolution and disease emergence in carnivores.
>
> McCarthy AJ, Shaw MA, Goodman SJ.
> Institute of Integrative and Comparative Biology, Faculty of=20
> Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
> Emerging infectious diseases constitute some of the most pressing=20
> problems for both human and domestic animal health, and=20
> biodiversity conservation. Currently it is not clear whether the=20
> removal of past constraints on geographical distribution and=20
> transmission possibilities for pathogens alone are sufficient to=20
> give rise to novel host-pathogen combinations, or whether pathogen=20
> evolution is also generally required for establishment in novel=20
> hosts. Canine distemper virus (CDV) is a morbillivirus that is=20
> prevalent in the world dog population and poses an important=20
> conservation threat to a diverse range of carnivores. We performed=20
> an extensive phylogenetic and molecular evolution analysis on=20
> complete sequences of all CDV genes to assess the role of selection=20
> and recombination in shaping viral genetic diversity and driving=20
> the emergence of CDV in non-dog hosts. We tested the specific=20
> hypothesis that molecular adaptation at known receptor-binding=20
> sites of the haemagglutinin gene is associated with independent=20
> instances of the spread of CDV to novel non-dog hosts in the wild.=20
> This hypothesis was upheld, providing compelling evidence that=20
> repeated evolution at known functional sites (in this case residues=20
> 530 and 549 of the haemagglutinin molecule) is associated with=20
> multiple independent occurrences of disease emergence in a range of=20
> novel host species.
> PMID: 17956850 [PubMed - as supplied by publisher]
More on CDV ahead of print (Shelters and vets will love these.):
> J Virol Methods. 2007 Oct 19; [Epub ahead of print]
> An immunochromatography assay for rapid antemortem diagnosis of=20
> dogs suspected to have canine distemper.
>
> An DJ, Kim TY, Song DS, Kang BK, Park BK.
> National Veterinary Research and Quarantine Service, Anyang,=20
> Kyunggi-do 430-824, Republic of Korea.
> A new assay was developed for rapid and antemortem diagnosis of=20
> canine distemper (CD). This immunochromatography (IC)-based assay,=20
> which employs two monoclonal anti-CDV antibodies, was compared with=20
> nested PCR. When serial dilutions of purified CDV were tested, the=20
> CDV detection limits of the nested PCR and IC assays were 2x10(2)
> TCID(50)/ml and 5x10(2)TCID(50)/ml, respectively. Nasal irrigation=20
> fluid, conjunctival swabs, and blood lymphocytes from 66 dogs=20
> suspected to have CD were tested. Preliminary IC experiments=20
> revealed that the optimal sample volume and reaction time were=20
> 100mul and 5min, respectively. Relative to nested PCR, the=20
> sensitivity and specificity of the IC assay was maximal (100% and=20
> 100%, respectively) when conjunctival swabs were tested. This is=20
> significant because conjunctival swab specimens are easy to obtain=20
> in the early phase of CD infection. However, with blood lymphocytes=20
> and nasal samples, the IC assay was slightly less sensitive (89.7%=20
> and 85.7%, respectively) and specific (94.6% and 100%,=20
> respectively) than nested PCR. Since this novel IC assay does not=20
> require special instruments, it is a simple enough for dog owners=20
> to use. Since early detection of CD would allow appropriate=20
> treatment and quarantine to be instituted quickly, such a test=20
> would help reduce the morbidity and mortality associated with CD=20
> help to prevent its spread to other animals.
> PMID: 17950910 [PubMed - as supplied by publisher]
> Antiviral Res. 2007 Oct 8; [Epub ahead of print]
> In vitro efficacy of ribavirin against canine distemper virus.
>
> Elia G, Belloli C, Cirone F, Lucente MS, Caruso M, Martella V,=20
> Decaro N, Buonavoglia C, Ormas P.
> Department of Animal Health and Well-being, Faculty of Veterinary=20
> Medicine of Bari, S.p. per Casamassima km 3, 70010 Valenzano, Bari,=20
> Italy.
> Despite vaccination, canine distemper virus (CDV) remains one of=20
> the important pathogen of dogs with worldwide distribution.=20
> Ribavirin (RIB) inhibits replication of measles virus (MV), a=20
> morbillivirus closely related to CDV, both in vitro and in vivo. In=20
> this report the antiviral activity of RIB against CDV in cell=20
> cultures was assessed. Quantitative real-time RT-PCR was used to=20
> measure viral RNA in VERO cells infected by CDV and to evaluate the=20
> inhibitory effects of RIB. RIB caused a dose- and time-dependent=20
> decrease in accumulation of CDV RNA when added after virus=20
> adsorption. RIB was highly effective in preventing CDV replication=20
> at low concentrations with 50% virus-inhibitory concentrations=20
> ranging from 0.02 to 0.05mM. Such low values were comparable to=20
> values displayed by highly susceptible strains of MV. In addition,=20
> CDV was passaged sequentially in VERO cell monolayers in the=20
> presence of RIB to trigger viral extinction. The virus was no=20
> longer detected after three passages, suggesting that error=20
> catastrophe is one of the modes of action of RIB against CDV. These=20
> findings suggest RIB as a promising tool for the therapy of CD in=20
> dogs.
> PMID: 17949825 [PubMed - as supplied by publisher]
In addition, the first ever documented case of Canine Distemper in a=20
Siberian Tiger has occurred which may lead to questions if a strain=20
of the virus has altered there. It was found in a wild Siberian=20
Tiger in the Russian Far East. In recent decades there have been=20
devastating cases involving the Black Footed Ferret, lions, and=20
leopards in some regions, usually with it thought that the disease=20
spreading because of unvaccinated domestic dogs outside.
BTW, skunk people here might want to see:
J Zoo Wildl Med. 2007 Sep;38(3):388-99.
Suppurative polyarthritis in striped skunks (Mephitis mephitis) from=20
Cape Cod, Massachusetts: detection of mycoplasma DNA.
Ganley-Leal LM, Brown C, Tulman ER, Bergman L, Hinckley L, Johnson=20
KH, Liu X, Van Kruiningen HJ, Frasca S Jr.
Sukie (not a vet)
Recommended ferret health links:
http://pets.groups.yahoo.com/group/ferrethealth/
http://ferrethealth.org/archive/
http://www.afip.org/ferrets/index.html
http://www.miamiferret.org/fhc/
http://www.ferretcongress.org/
http://www.trifl.org/index.shtml
http://homepage.mac.com/sukie/sukiesferretlinks.html
[Non-text portions of this message have been removed]
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