Epidemiology work on rabies

8/10/2019 Epidemiology work on rabies

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Epidemiology &Prevention:

RABIES


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Rabies, present on all continents and endemic in most African

and Asian countries, is a fatal zoonotic viral disease, transmittedto umans troug contact !mainly bites and scratces" #it

infected animals, bot domestic and #ild$

Rabies is estimated to cause at least %% deats per year#orld#ide, about %'( of #ic occur in Asia and ))( in Africa,particularly in rural areas on bot continents$ In Africa and Asia,tese deats are responsible for *$+) million disabilityad-usted

life years !.A/0s" lost eac year$ 1e estimated annual cost ofrabies is 2S3 %45$% million, most of tis cost being borne byAsian countries #ere large amounts of post e6posurepropyla6is are administered$ 7ost post e6posure propyla6isneeds are borne by patients #o can least a8ord to pay$ Anestimated * million people #orld#ide receive poste6posure

treatment after being e6posed to animals suspected of rabies$

Introduction


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1ere is no speci9c treatment for rabies, #ic is afatal disease$ !Supportive treatment alone as beensuccessful in one recentlyreported con9rmed case

of uman rabies in te 2nited States of America$";< promotes:

uman rabies prevention troug: #elltargeted post e6posure treatment using modern

vaccine types and, #en appropriate, antirabies

immunoglobulin=

pree6posure propyla6is using modern vaccine typesfor certain professional groups at iger ris> and alsoif

vaccines are easily accessible, of cildren aged under*% in areas #ere rabies is yperendemic=

increased access of safe and e8ective rabies vaccines$

dog rabies elimination troug mass vaccination ofdogs and dogpopulation management$


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?ausal agent: /yssaviruses of te Rabdoviridae

family$

7ain modes of transmission: ;osts are usually?anidae, including dogs !responsible for more tan@@( of all uman deats from rabies", fo6es, coyotes,#olves and -ac>als= also cats, s>un>s, raccoons,

mongooses, bats and oter biting animals$ A bite or ascratc introduces virusladen saliva from a rabidanimal$ 1e incubation period ranges from a fe# daysto several years !most commonly 54 #ee>s"$

?ausal agent andmain modes oftransmission


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?linical description

Paresis or paralysis, delirium, convulsions$

itout medical attention, deat in about ' days, usuallycaused by respiratory paralysis$

?linical case de9nition:

A person presenting #it an acute neurological

syndrome !encepalitis" dominated by forms ofyperactivity !furious rabies" or paralytic syndromes !dumbrabies" progressing to#ards coma and deat, usually byrespiratory failure, #itin +* days after te 9rst symptomif no intensive care is instituted$

?linical descriptionand recommended

case de9nition


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/aboratory criteria

in biopsy !ante mortem"$

A1 positive after inoculation of brain tissue,saliva or ?S in cell culture, or after intracerebralinoculation in mice or in suc>ling mice$

.etectable rabiesneutralizing antibody titer inte serum or te ?S of an unvaccinated person$

.etection of viral nucleic acids by P?R on tissuecollected post mortem or intra vitamin in a clinicalspecimen !brain tissue or s>in, cornea, urine orsaliva"$


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Human rabies

Suspected: A case tat is compatible #it te clinical case de9nition$

Probable: A suspected case plus istory of contact #it a suspected rabid

animal$ ?on9rmed: A suspected case tat is laboratorycon9rmed$

Human exposure to rabies

Possible e6posure: A person #o ad close contact !usually a bite orscratc" #it a rabiessusceptible animal in !or originating from" a

rabiesinfected area$ Probable e6posure: A person #o ad close contact !usually a bite or

scratc" #it an animal displaying clinical signs consistent #it rabies attime of te e6posure, or #itin * days follo#ing e6posure in a rabiesinfected area$

E6posed: A person #o as ad close contact !usually a bite or scratc"#it a laboratorycon9rmed rabid animal$

?ase classi9cation

!umans"


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Rationale for surveillance

Surveillance of bot uman and animal rabies isessential to detect igris> areas andoutbrea>s Cuic>ly and to monitor te use ofvaccine$

Surveillance


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Surveillance in uman populations

Surveillance of uman e6posure to rabies$ Reports of patients#it a istory of animal contact !usually a biteDscratc",

especially in rabiesinfected areas, to be investigated at once$?asebased and aggregated data must be sent regularly fromte local level to te intermediate and central levels$

Surveillance of cases of uman rabies$ Immediate reporting ofsuspected and con9rmed cases from te local level !bydiagnosing pysician and laboratory" to te intermediate and

central levels$ Rapid e6cange of information #it services in carge of animal

rabies surveillance and control is reCuired$

Epidemiological investigation of outbrea>s: investigation of allrabies foci, identifying sources of infection as #ell as umansand animals e6posed or possibly e6posed$

Recommended types

of surveillance


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Surveillance in animal populations

ere te disease is endemic or could be reintroduced,underta>e surveillance of animal rabies and similar

conditions in #ild and domestic species most li>ely to bereservoirs of disease$ Surveillance is laboratorybased$

1ere sould be immediate submission of a brainspecimen of te suspected animal for laboratorydiagnosis #en uman e6posure occurs$ Suspecteddomestic animals at te origin of uman e6posure tatcannot be >illed must be >ept under observation for *days$ Rapid e6cange of information bet#een servicesin carge of uman and animal rabies surveillance andcontrol is reCuired$ In circumstances #ere samplescannot be collected from te suspected rabidanimal or

a laboratory diagnosis cannot be made, cases to berecorded as suspected animal rabies cases on te basisof clinical signs= and tese data sould also be collectedand e6canged #it public ealt autorities$

R d d


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Human rabies exposure

?asebased data$ 2niCue identi9er, name, age,geograpical information, date of onset of symptoms,date!s" of biteDscratc, geograpical information,!location" of biting episode!s", category of e6posure, local#ound treatment, vaccination istory, previous serumtreatment, current treatment, outcome= details of bitinganimal, vaccination istory, samples ta>en, samples

outcome, outcome$ Aggregated data reporting

E6posures by geograpical information on biting episode,biting animal, outcome in animal and uman populations$

Surveillance of deats from uman rabies$

Recommendedminimum data

elements


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Recommended data analyses, presentation,

reports

umber of uman rabies deats and rabiescases in animals !by species", by date of

presentation$ ;uman e6posures by location and dates of

bitingDscratc episode, animal species at originof e6posure and by outcome in uman and inanimal populations$

?ases by geograpical area !e$g$ district", datesof bitingDscratc episode, type of animal,occupation and outcome$


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?ase management of bitten patients

Immediate and toroug cleaning of te #ound #it

soap, follo#ed by etanol or aCueous iodine$ Post e6posure propyla6is !PEP" if reCuired:

administration of rabies immunoglobulin in case ofsevere e6posure !;< category 5"$

PEP to be applied as soon as possible F vaccines

#it a potency at least G$% I2 per single immunizingintramuscular dose according to one of te follo#ingscedules: !Holume of * intramuscular dose afterreconstitution may vary according to vaccine brand$"

?ontrol activities


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?oncentrated and puri9ed cellculture and embryonated

eggbased rabies vaccines !ere -ointly referred to as??Hs" ave proven to be safe and e8ective inpreventing rabies$

1ese vaccines are intended for pree6posurepropyla6is as #ell as poste6posure propyla6is, andave been administered to millions of people #orld#ide$

Rabies di8ers from many oter infections in tat tedevelopment of clinical disease can be preventedtroug timely immunization even after e6posure to teinfecting agent$

Haccinations and

immunization


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Essen regimen: * dose on days , 5, +, *) and G4$ All

intramuscular in-ections to be given into deltoid regionor anterolateral area of tig muscle in small cildren$ever in-ect te vaccine in te gluteal region$

G** regimen: G doses on day !one in te deltoidregion of te rigt arm and te oter in te deltoidregion of te left arm"$ * dose in te deltoid region onday + and * on day G*$ 1is regimen is particularlyrecommended #en no immunoglobulin is reCuired, i$e$#en contact consists in nibbling of uncovered s>in,minor scratces or abrasions #itout bleeding, or lic>son bro>en s>in$

Intramuscular

scedules


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1e follo#ing intradermal regimens ave been so#n to be

immunogenic: Gsite intradermal metod !GGG** and GGGG" for use #it

puri9ed vero cell vaccine !PHRH", puri9ed primary cic> embryo cellvaccine !P?E?H" and uman diploid cell !;?.H" at $* ml perintradermal in-ection site F days , 5 and +: $* ml at eac of G sites,

intradermally on upper arm, over eac deltoid$ .ays G4 and @: $* mlat * site, on upper arm$ 1e single dose of vaccine given on day @ ofte original 1ai Red ?ross regimen !GFGFGFF*F* regimen" can bereplaced if t#o doses of vaccine are given on day G4 !GFGFGFFGregimen"$

4site intradermal metod !4)**" for use #it uman diploid cellvaccine ;.?H, and P?E?H$ Regimen: day : $* ml at eac of 4 sites$

In-ect intradermally over deltoid, lateral tig, suprascapular regionand lo#er Cuadrant of te abdomen$ .ay +: $* ml of vaccine at eacof ) sites over deltoids and tigs$ .ays G4 and @: $* ml of vaccineat * site, over deltoid$

Intradermal in-ections must be given by sta8 trained in tis tecniCue$Haccine vials to be stored bet#een G ? and 4 ? after reconstitutionand total content to be used as soon as possible, at least #itin 4ours$ Rabies vaccines formulated #it an ad-uvant sould not beadministered intradermall $ 1e standard dose er id in ection site is

Intradermal

scedules


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Elimination of rabies virus at te site of te infection by

cemical or pysical means is an e8ective mecanism ofprotection$ /ocal treatment of #ounds involving possible

e6posure to rabies is recommended in all e6posures$ Recommended 9rstaid procedures include immediate and

toroug using and #asing of te #ound for a minimum of*% minutes #it soap and #ater, detergent, povidone iodineor oter substances of proven letal e8ect on rabies virus$

If soap or an antiviral agent is not available, te #ound souldbe torougly and e6tensively #ased #it #ater$ If suturingafter #ound cleansing cannot be avoided, te #ound sould9rst be in9ltrated #it passive rabies immunization productsand suturing delayed for several ours$

/ocal treatment of

#ounds


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Several vaccine types can de distinguised among te

secondgeneration veterinary vaccines, depending #etertey are live or inactivated, according to te strain of rabies

virus used and te caracteristics of te cell substratecosen for viral replication$

?onsiderable progress as been made in te production ofrabies vaccines #eter live or inactivated for animal useduring te past t#o decades #it te increasing use of

continuous cell lines as a substrate and adoption of tefermentor tecnology for antigen production$ 1esevaccines are produced for administration to domesticanimals or #ild species by parenteral or oral routesaccording to vaccine caracteristics$

Heterinary vaccines


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Immunize all dogs and cats o#ned by an individual or by tecommunity and reduce te size of te o#nerless dog population byreproduction control, reduction of te carrying capacity of teenvironment and la# enforcement #en needed$

Immunize any person #it proven or probable e6posure to rabies

and administer rabies immunoglobulin in case of severe e6posure!;< category 5"$

;umans at ig ris> !e$g$ laboratory personnel, professions at igris>" must receive pree6posure immunization: 5 in-ections of anintramuscular dose on days , +, and G4$

Pree6posure vaccine regimen: * dose of a cell culture or puri9ed

duc> embryo vaccine on days , +, G4$ A variation of a fe# days isacceptable$ 1e dose is * standard intramuscular dose !* ml or $%ml according to vaccine type"$ vaccine may be given intradermally!$* ml on days , +, G4" but intramuscular in-ections are preferableif antimalarial cemopropyla6is !e$g$ cloroCuine" is being usedconcurrently or tere is a possibility of an immunecompromisedstate !antibody response may be impaired if te intradermal

metod is used"$

Prevention


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?onditions under #ic epidemics may occur

Introduction of te virus into a rabiesfree area

#it a fully susceptible animal population$ A8ected areas #ere te dogDuman population

ratio is ig, #it little dog supervision andimmunization$

A8ected areas #it animal outbrea>s #ere nouman rabies vaccinesDimmunoglobulin areavailable$

Epidemics


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If an epidemic arises from a ne# introduction at one site, intensive

vaccination of dogs in combination #it dog population control andmovement restriction to be implemented immediately$ Public ealtautorities, particularly in isolated rabiesfree island communities, sould

ave a contingency plan for suc an event$ In animals

2nderta>e a dog immunization campaign: +%( of te dog population must bevaccinated #itin * mont$

Immunize domestic animals and !troug bait" #ild animals as appropriate$

EnactD enforce legislation on dog movement restriction$

Selective and umane capture and elimination of dogs not in compliance #it

legislation may be conducted in outbrea> situations$

In umans

Ensure availability of vaccine and immunoglobulin in te a8ected area$

1rain medical sta8 in de9ning #en PEP is needed, categories of e6posures and inte use of te intradermal tecniCue$

Investigate animal outbrea>s and identify uman contacts #it suspect animals$

Immunize any person #it proven or probable e6posure to rabies$

7anagement of

epidemics


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Procurement of eCuipment and drugs

A *ml syringe and a needle for eac intramuscular

in-ection !intradermal needles and syringes forintradermal vaccination"$

Haccine amounts: bet#een G and % vials, dependingon te metod used$

en embryo cell vaccine !P?E?H": RabipurK$


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Special considerationsDoter interventions

It is teoretically possible for persontoperson

rabies transmission to occur since secretionsmay contain te virus= tis as not beendescribed$ As a precaution, medical and nursingsta8 must #ear mas>, gloves, and goggles$ Inospitals and oter institutions caring for severalrabid patients, pree6posure vaccination ofmedical and nursing personnel sould beconsidered$ .o not use organs of patients #itrabies or any neurological disease fortransplantation$

Intersectoral cooperation of medical andveterinary services, community involvement andparticipation are reCuired for targeted responseand control in animal reservoirs$

Documents

Epidemiology work on rabies