Talk:Bluetongue disease

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I renamed the page to conform with standard terminology. Myron 10:50, 27 July 2005 (UTC)

Contents

[edit] Virus taxonomy

By my knowledge, bluetongue is a dsRNA-virus instead of a ds-DNA virus. Could somebody change this, because I find it hard to alter the Taxonomy boxes.

Gill De Deken Institute for Tropical Medicine (ITM) Antwerp Belgium —The preceding unsigned comment was added by 193.191.6.53 (talk) 15:39, 24 January 2007 (UTC).

[edit] Removed "current" tag

I have removed the "This article is related to a current event." tag because I don't believe the content will change significantly as a result of the emergence of bluetongue in the UK. This article is about a disease, not about specific outbreaks. If the emergence in the UK proves to be a major outbreak, then a separate article might be necessary. However, in this article it would only really merit an extra sentence or two.--86.146.242.16 10:05, 23 September 2007 (UTC)

No problem easily enough changed if events turn out otherwise, however my suspicion is that a lot of the traffic and interest in the next couple of days will be due to the UK outbreak, I'm certain that the current spate of vandals has been because of the UK coverage. KTo288 11:41, 23 September 2007 (UTC)

[edit] Life cycle

Could do with a section on life cycle and transmission. The midge vector is mentioned, and replication in both hosts, but that's about it. For example, how long can it maintain itself in either host? Can it persist through cold periods in temperate regions, and if so, how? Why is it generally associated with warm climates, if Culicoides species and suitable mammalian hosts are also widespread in temperate ones?--Richard New Forest 07:47, 26 September 2007 (UTC)

Apparently there is some evidence that certain equids (particularly zebras, and possibly donkeys, but not E. callabus) act as maintenance hosts allowing viral replication without clinical disease. However, this data is from a lecture delivered at a conference, and I have no published sources for it - does anyone else? Dlh-stablelights 09:23, 11 October 2007 (UTC)

Is this referring to bluetongue itself, or the equine equivalent, African horse sickness?.
I found a paper about possible mechanisms for over-wintering of the ruminant disease in sheep. They found that virus may persist without symptoms in skin tissues long after it has cleared from the blood; they also cultured virus in other tissues in vitro. The reference is:
Takamatsu, H., Mellor, P. S., et al (2003). A possible overwintering mechanism for bluetongue virus in the absence of the insect vector. Journal of General Virology 84: 227-235. (Available online at http://www.sgm.ac.uk/jgvdirect/18705/18705ft.pdf).
I'm not competent to extract the relevant parts of this paper, but it would be very useful if someone who is, could. I've put the link in External Links for the moment.--Richard New Forest 10:27, 11 October 2007 (UTC)

[edit] Symptoms

A recent UK TV programme (Countryfile, BBC1, 23 Sept) had an item on bluetongue, and showed further symptoms to those described here. Were those correct? They included, as I recall, infection of joints, leading to abcesses which then burst -- there was a particularly gruesome shot of a sheep's exploded knee-joint.--Richard New Forest 07:56, 26 September 2007 (UTC)

Actually I believe it was the Countryfile edition of 16 September -- I'm behind with watching the recordings!--Richard New Forest 16:04, 28 September 2007 (UTC)

[edit] Vaccine section

This section appears to be text taken wholesale from a scientific paper (is it copyright?). The style and content are also inappropriate: it's partly in the first person, it's very over-technical, and in fact I don't think much of it is relevant (apparently it's just a report of certain experiments, with no clear indication of whether the results will lead to a practical vaccine nor what other approaches might work). Finally, the reference from this section does not seem to be correct.

I think what is needed here instead is a much more general discussion of whether a vaccine is available, and if not, what progress is being made ("within a year" is what an NFU rep on the telly said, perhaps over-optimistically).--Richard New Forest 08:23, 26 September 2007 (UTC)

I think the technical nature of the vaccine section is justified and will be of interest to many people of a technical inclination. However I also agree that it should be expanded to include a more general discussion of a non-technical nature and I would welcome a contribution of this nature. The current information is taken from the source referenced (it is the correct reference) with the permission of the copyright owner. The material on the page is therefore available under a GFDL license. Touchstone42 14:29, 2 October 2007 (UTC)

Perhaps I was being a little kind... When I said "technical", perhaps I should have said "impenetrable". I have a good scientific training, but I find the section as written very hard going, and it took three or four readings to get it. What is appropriate here is a much shorter summary for the intelligent lay reader.
If it is appropriate at all... The quoted text does not really discuss vaccines in general, but only describes one promising process in detail. Do existing vaccines use this process, or do they use others? If others, what are the characteristics and advantages of different methods? Is the vaccine approach described unique to bluetongue and similar viruses? If not, it does not belong here but in a general article about vaccines, with a link if necessary.
Either way, the point about the language of the text still stands . It has phrases such as "allowed us to", "a number of experiments were performed", "recombinant viruses were prepared" etc. Such phrases are perfectly appropriate in a paper describing what "we" did, but not in an encyclopedia article. Such an article should not quote wholesale and should summarise in an impersonal tone: "...recent research has shown...", "recombinant viruses have been used" etc. Concepts unfamiliar to a lay reader also need explaining – for example, it is not enough to say "attenuated, live virus vaccines are not desirable" – why not? Are they hard to prepare, do they get out of control in culture, do they mutate in the host, do they smell bad – what? To a virologist this might be obvious, but to a lay person it is not and needs explanation or at least a reference or link.
I'm still not sure the reference (2: Roy, P etc) is right. The link goes to a very long synopsis of a book, and a search for "bluetongue" will eventually lead to the right chapter some way down the page. However, only a synopsis is given for the chapter, and this only mentions research into the virus's structure, not anything about a vaccine preparation method. Is the copied text really from this, or from somewhere else? If indeed from this, a more detailed ref is needed.
I suggest that the first paragraph of the vaccine section should remain, but the whole of the remainder should be removed for the moment and replaced, when written, with much shorter more general information in an appropriate tone. --Richard New Forest 12:20, 11 October 2007 (UTC)

As there have been no further comments for several weeks, I have removed the text in question, which is saved here:

Since it is a vector-borne disease and transmitted to healthy livestock from infected animals by blood feeding Culicoides spp., attenuated, live virus vaccines are not desirable. The flexibility of baculovirus expression vectors and the capacity of the baculovirus genome to accommodate large amounts of foreign DNA allowed us to exploit the system for the simultaneous expression of multiple BTV genes by a single recombinant virus. Based on the 3D structural data, recombinant viruses were prepared to express either VP3 and VP7, the two major core proteins, or VP3 and VP7 together with VP2 and VP5, i.e. all four major structural proteins. Expression of VP3 and VP7 resulted in CLPs that were similar in size and appearance to cores prepared from BT virions. Similarly, the simultaneous expression of four proteins resulted in the assembly of virtually homogeneous doublecapsid particles. When the 3D structure of CLPs and VLPs were analysed by Cryo-EM both types of particles were clearly comparable to authentic cores and virions, and exhibited essentially the same basic features and full complement of the two or four proteins. VLPs synthesized by recombinant baculoviruses were also characterized further at the biological and immunological levels and compared to those of the native virion. VLPs exhibited high levels of haemagglutination activity similar to those of authentic BTV. Further antibodies raised to the expressed particles contained high titres of neutralizing activity against the homologous BTV serotype emphasizing their authenticity at functional level.

Since VLPs elicited strong neutralizing antibodies in guinea pigs, it can be anticipated that VLPs should also elicit protective responses in sheep against BTV infection. Consequently, a number of experiments were performed to examine the protective efficacy of VLPs (10-200 µg per sheep) in 1-year old BTV free sheep divided in groups (4-8 sheep/group). All sheep were challenged by subcutaneous inoculation of 1 ml of infective sheep blood containing virulent virus at day 117 or at 14 months. The challenged sheep developed neither clinical signs nor viraemia, indicating a suppression of BTV replication. The post-challenge blood samples of the sheep that did not receive vaccine and only received saline, contained infectious BTV and these sheep developed high neutralizing antibody titres indicative of a primary infection. Protective immunity to BTV disease was obtained by vaccinating sheep with doses of 10 µg or more of BTV VLPs which resulted in long-lasting protection against homologous BTV challenge. Some preliminary evidence was obtained for crossprotection, depending on the challenge virus and the amounts of antigen used for vaccination.[1]

--Richard New Forest 16:39, 30 October 2007 (UTC)

just a remark to the serotype 8 vaccine: there exists a South African version, but tests showed it caused abortions with the european races. 84.194.181.70 (talk) 17:58, 28 November 2007 (UTC)

[edit] Contagious?

The article was just changed to say bluetongue is "highly contagious" (from "non-contagious").

Is this correct? The Concise Oxford Dictionary defines contagious as

  • "communicating disease by contact; (of disease) so communicable".

The derivation is given as from Latin tangere to touch. My understanding is that this disease is transmitted by a vector, not by contact, and as such it is surely infectious but not contagious?

I have reverted it for the moment, but if anyone has evidence it is indeed spread by contact, please change it back.--Richard New Forest 16:01, 28 September 2007 (UTC)

According to the [BBC] the disease needs midges to spread the disease, however it is possible that using contaminated needles may spread the disease. KTo288 19:18, 28 September 2007 (UTC)

[edit] Copyright

I think there is a problem with copyright. The text about the virus is exactly the same like here. --84.184.82.105 (talk) 16:27, 12 December 2007 (UTC)

Good eye, but if you look at the user page of the person who added that (User:Touchstone42), there is an explanation. The text from the webpage you reference is released under the GFDL license, and apparently this user reuses it with permission. It is referenced back to that page, also. --Joelmills (talk) 04:01, 13 December 2007 (UTC)
Sorry, I didn't saw the license. --79.213.90.70 (talk) 08:28, 13 December 2007 (UTC)