how we control viral diseases of man and animals

7/23/2019 How We Control Viral Diseases of Man and Animals

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ow we con ro v radiseases of man and

animals.

by Peter Russell

[email protected]://www.rvc.ac.uk/Staf/prussell.cm


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$iral diseases.%ow viruses are transerred.%ow viruses are controlled &this lectur


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Viral diseases.

$iral diseases cause distress to man andanimals and the most worryin" ones are thosethat are di(cult to control.%uman immunode)ciency virus &%I$' continuesto spread in an uncontrolled manner.

How viruses are transferred.$iruses are carried by inected people oranimals and e*creted in dischar"es such asthose rom the nose+ "ut and reproductive ,uids.#he control o viruses blocks this transer.

How viruses are controlled (this lecture).-ontrol measures or viruses.bstacles to the control o viruses.

ays to improve the control o viruses.


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-ontrol measures or viruses.0' 1uarantine' Import controls!' 2oti)cation

3' Slau"hter4' 5econtamination6' Isolation

7' #reatment8' $accination9' Insect controls


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1) Quarantine.Separate the infected persons or animals withsigns suspicious of an acute viral disease such

as rash, vesicles, vomiting with diarrhoea.) !mport controlsBlocking animal imports from a countr" suchas one infected with foot and mouth diseasevirus (#$%V) or avian in&uen'a.

) oti*cation.oti*a+le diseases of man include H!V,measles, mumps and ru+ella and those ofanimals include #$%V, swine fever and ra+ies.n"one who suspects a noti*a+le disease

must contact the national authorities. See -links for those of man and animal +elow./he authorities inform the 0orld Healthorganisation (0H) or 0orld organisation foranimal health (formerl" the !2).

/hese organisations pu+licise the glo+alspread of diseases.


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-ontrol measures or viruses.0' 1uarantine' Import controls!' 2oti)cation


7' #reatment8' $accination9' Insect controls


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3) Slaughter.-ullin" the inected animal or herd.$iruses reuire livin" cells to multiply and this is halted bythe death or slau"hter o an animal.

4) %econtamination.ashin" and disinectin" hands+ clothin" and euipment.

5isposin" o dead bodies in a sae manner likeincineration or burial in lime.#reatment o waste water and chlorination o mains water.Personal hy"iene e.". not cou"hin" over people andwashin" hands ater toilet and beore ood preparation.

5) !solation.;voidin" multiple close contacts such as in crowdedhousin".; secure arm will also e*clude other animals and visitors

that mi"ht transer the virus.


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-ontrol measures or viruses.0' 1uarantine

' Import controls!' 2oti)cation3' Slau"hter4' 5econtamination6' Isolation7' #reatment8' $accination+ part 09' Insect controls


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7' #reatment.

;ntiviral dru"s are used or only a ew viruses becausethey are e*pensive+ oten have side efects and they

select or resistant viruses.#hey e*ist or %I$+ hepatitis


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-ontrol measures or viruses.

0' 1uarantine' Import controls!' 2oti)cation


7' #reatment8' $accination+ part 9' Insect controls


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-ontrol measures or viruses.0' 1uarantine

' Import controls!' 2oti)cation3' Slau"hter

4' 5econtamination6' Isolation7' #reatment

8' $accination+ part !9' Insect controls


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;lthou"h vaccines only protect a"ainst a particularvirus+ like AB5$+ they can also be speci)c to aparticular serotype+ AB5$ + or even a particularsubdivision o a serotype termed subtype+ AB5$0.

ne unction o viral dia"nostic laboratories is todetermine e*actly which serotypes and subtypes

o viruses are circulatin" so the vaccine industrythen makes vaccines that work a"ainst the viruscausin" an outbreak.

6) !nsect controls.

Individuals use insecticidal creams+ protectiveclothin" and mosuito nets.Covernments can interrupt the liecycle o insectsby chemicals that kill their larvae or by removin"their habitats e.". by drainin" sta"nant water.


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bstacles to the control oviruses.

0' Poor inrastructure

' Clobal transport!' Butation3' $accine desi"n

4' Reservoir hosts and insecthosts6' Rumours about vaccines

7' Dnsatisactory vaccines


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1) 7oor infrastructure.I there is a shorta"e o inrastructure to enorce thecontrols o human and animal viruses.

Aor instance viruses spread durin" con,icts whenhy"iene and borders are disrupted and people aredisplaced into camps.Drban poverty is where antisocial behaviour such asdru" use and prostitution become more likely.

) 8lo+al transport.%I$ ori"inated in ;rica and has spread worldwide.AB5$ has re>entered Europe as waste meat in untreatedpi" swill and has then spread rapidly via animal

movements and markets when animals with vesiclesescaped notice.

) $utation.$iruses mi"ht mutate to inect new species or instance

the worry that avian in,uen=a virus mi"ht mutate tobecome a pandemic not only o birds but o man.


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bstacles to the control o viruses.

0' Poor inrastructure' Clobal transport!' Butation

3' $accine desi"n4' Reservoir hosts and insect hosts6' Rumours about vaccines

7' Dnsatisactory vaccines


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3) Vaccine design.Some viruses have a protein structure that meansvaccines work badly or never e.". ;rican swine

ever+ %I$.ther viruses have vaccines that only work to aparticular strain o a subtype e.". in,uen=a virus.#hese strains chan"e each year and so the %advises on which strains to use in vaccines or a

particular country.

4) 9eservoir hosts and insect hosts.#he virus e*ists in reservoirs hosts e.". rabies indo"s that bite man+ or other do"s+ when the

rabies encephalitis makes them become urious.#he virus replicates in insects as well as man andanimals e.". yellow ever virus and est 2ile virusare transerred to man by mosuito bites.


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bstacles to the control o viruses.0' Poor inrastructure' Clobal transport

!' Butation3' $accine desi"n4' Reservoir hosts and insect hosts

6' Rumours about vaccines7' Dnsatisactory vaccines


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6' Rumours about vaccines.

#hese include:

autism rom the combined mumps+ measles

and rubella &BBR' vaccine+

inertility rom polio vaccines+

aborted calves and lambs rom inactivated

blue ton"ue vaccines.

7' Dnsatisactory vaccines.

#hese include:

countereit vaccines+homeopathic vaccine+

little or no viral content+ i.e. poor ualitycontrol .


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ays to improve the control o virus

0' Bore vaccine covera"e' 2ew vaccines!' %y"iene

3' -heaper easier vaccines4'


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1) $ore vaccine coverage.

#o establish more universal vaccination pro"rammesusin" the licensed e*istin" vaccines that work e.".

BBR a"ainst mumps+ measles and rubella and also

those a"ainst rabies o reservoir hosts.

) ew vaccines.

#o develop vaccines a"ainst viruses that have noworkin" vaccine e.". %I$+ 5en"ue ever.

) !mproved h"giene.

#o improve communal hy"iene and well bein" e.".drains+ clean water+ spacious housin"+ nutrition+discoura"in" intravenous dru" use and unprotectedse*.


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ays to improve the control o virus0' Bore vaccine covera"e' 2ew vaccines!' %y"iene3' -heaper easier vaccines4'


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3) $ore useful vaccinescheaper workin" dose+

less loss by heat durin" stora"e

easier administration.

4) Better reporting and feed+ack.#o have dia"nostic and surveillance teams in place to

warn how outbreaks are spreadin" and to inormvaccine manuacturers o how many doses to make othe vaccine a"ainst the correct virus or even subtypeo virus.

#hey also advise the "eneral public+ medics and vetson how to reco"nise si"ns o the disease&s'.

5) $aths.#o develop mathematical models to establish thecheapest and best ways o controllin" diseases o man

and animals e.". by public health measures andvaccination.


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ays to improve the control o viruse




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:) ;heaper antiviral drugs.

#hese also must not "et out o date as result o

viruses mutatin" to escape their efects.


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ays to improve the control o viruse




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6) ;ommunication#o educate the "eneral public about

methods o reducin" virus spread such as:

reportin" disease e.". AB5$ andmeasles+ disinection o hands and suraces e.". inthe kitchen+ hospital and inected arm+ becomin" more aware o how someviruses+ e.". %I$ and hepatitis


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Summary#he control o viral diseases

must block their transerrom inected to uninected =onesby hy"iene and vaccination

schemes..

how we control viral diseases of man and animals

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