zika virus infection and zika fever

7/25/2019 Zika Virus Infection and Zika Fever

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Zika virus infection and Zika fever: Frequently asked questions

Updated: 6 January 2016

What is Zika virus infection?

Zika virus infection is caused by the bite of an infected Aedes osquito! usually causin" ild fever! rash! con#unctivitis!

and uscle pain$

%he virus &as isolated for the first tie in 1'() in the Zika forest in U"anda$ *ince then! it has reained ainly in

Africa! &ith sall and sporadic outbreaks in Asia$ +n 200)! a a#or epideic &as reported on the island of ,ap-.icronesia/! &here nearly ) of the population &as infected$

n 3 .arch 201(! 4hile notified 5A78 that it had confired a case of indi"enous transission of Zika virus on

9aster +sland! &here the virus continued to be detected until June 201($

+n .ay 201! the public health authorities of ra;il confired the transission of Zika virus in the northeast of the

country$ *ince ctober 201! other countries and territories of the Aericas have reported the presence of the virus$

*ee updated list at: &&&$paho$or"7;ikavirus$

What are the symptoms?

%he ost coon syptos of Zika virus infection are ild fever and e


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How is Zika diagnosed?

+n ost people! dia"nosis is based on clinical syptos and epideiolo"ical circustances -such as Zika outbreak in the

patient@s area or trips to areas &here the virus is circulatin"/$

lood tests can help to confir the dia"nosis$ *oe -virolo"ical 54? tests/ are useful in the first 3= days after the

onset of syptos! &hile others -serolo"ical tests/ detect the presence of antibodies but are useful only after five

days$

nce it has been deonstrated that the virus is present in a "iven area or territory! confiration of all cases is notnecessary! and laboratory testin" &ill be ad#usted to routine virolo"ical surveillance of the disease$

Which is the difference between Zika, dengue, and chikungunya?

All these diseases present siilar syptos! but certain syptos su""est one disease or another:

en"ue usually presents &ith hi"her fever and ore severe uscle pain$ %here can be coplications &hen the fever

breaks: attention should be paid to &arnin" si"ns such as bleedin"$

4hikun"unya presents &ith hi"her fever and ore intense #oint pain! affectin" the hands! feet! knees! and back$ +t can

disable people! bendin" the over so that they cannot &alk or perfor siple actions such as openin" a &ater bottle$

Zika does not have clearly characteristic features! but ost patients have skin rashes and soe have con#unctivitis$

Is there a relationship between uillain!"arr# syndrome and Zika virus?

An increase in Buillain=arrC syndroe -B*/ has been observed in areas &here a Zika virus epideic has been

docuented -e$"$! in French 5olynesia and ra;il/$

o&ever! a direct causal relationship has not been established bet&een Zika virus infection and B*$ 5rior infection &ith

den"ue or "enetic factors could contribute to or increase cases of B*$ *everal studies are under&ay to better establish

the relationship bet&een Zika and B*$

B* occurs &hen a person@s iune syste attacks itself! in particular affectin" the cells of the nervous syste$ %his

process can be initiated by infection &ith various viruses or bacteria$ %he ain syptos include uscular &eakness andtin"lin" -paresthesia/ in the ars and le"s! and severe coplications can occur if the respiratory uscles are affected$

%he ost seriously ill patients need attention in intensive care units$

CI$C%&'(I)* )+ ZI' -I$%.

Which countries have reported cases of Zika in the 'mericas?

n 3 .arch 201(! 4hile notified 5A78 that it had confired a case of indi"enous transission of Zika virus on

9aster +sland! &here the virus continued to be detected until June 201($

+n .ay 201! the public health authorities of ra;il confired the transission of Zika virus in the northeast of the

country$ *ince ctober 201! other countries and territories of the Aericas have reported the presence of the virus$

-*ee updated list at: &&&$paho$or"7;ikavirus$

What causes rapid transmission in an area?

%here are t&o factors for rapid transission -docuented in other countries/: -1/ *ince this is a ne& virus to the

Aericas! the entire population is susceptible! lackin" defenses to Zika virusD and -2/ %he Aedes osquito is &idespread

in the ?e"ion! "iven the cliatic conditions! teperature! and huidity in tropical countries$

Is it advisable to travel to countries where Zika virus is circulating?

5A78 does not recoend any travel or international trade restrictions related to Zika virus outbreaks$

%ravelers are advised to take the su""ested precautions to prevent osquito bites$

How many Zika cases have been reported in the $egion of the 'mericas?

4ountries be"in reportin" &hen they detect the circulation of the virus in their territories$ o&ever! aintainin" a case

count is difficult because syptos of the disease tend to be ild and not everyone affected is seen by health services$

8hat is ost iportant is to detect the circulation of the virus! stren"then the response of health services! and step up

surveillance of serious cases and coplications$
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What measures should be taken to prevent Zika virus infection?

5revention involves reducin" osquito populations and avoidin" bites! &hich occur ainly durin" the day$ 9liinatin" and

controllin" Aedes ae"ypti osquito breedin" sites reduces the chances that Zika! chikun"unya! and den"ue &ill be

transitted$ An inte"rated response is required! involvin" action in several areas! includin" health! education! and the

environent$

%o eliinate and control the osquito! it is recoended to:

Avoid allo&in" standin" &ater in outdoor containers -flo&er pots! bottles! and containers that collect &ater/ so

that they do not becoe osquito breedin" sites$

4over doestic &ater tanks so that osquitoes cannot "et in$

Avoid accuulatin" "arba"e: 5ut it in closed plastic ba"s and keep it in closed containers$

Unblock drains that could accuulate standin" &ater$

Use screens and osquito nets in &indo&s and doors to reduce contact bet&een osquitoes and people$

%o prevent osquito bites! it is recoended that people &ho live in areas &here there are cases of the disease! as &ell

as travelers and! especially! pre"nant &oen should:

4over e


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Zika virus

January 2016

ey +acts

Zika virus is transitted to huans by infected osquitoes$ +t causes ild fever and rash$ ther syptos include

uscle pain! #oint pain! headache! pain behind the eyes and con#unctivitis$

Zika virus disease is usually ild! &ith syptos lastin" only a fe& days$

%he disease has siilar clinical si"ns to den"ue! and ay be isdia"nosed in areas &here den"ue is coon$ %here is no cure for Zika virus disease$ %reatent is focused on relievin" the syptos$

5revention and control relies on reducin" the breedin" of Aedesosquitoes and inii;in" contact bet&een osquito

vectors and people by usin" barriers -such as repellents! insect screens/! reducin" &ater=filled habitats supportin"

osquito larvae in and close to d&ellin"s! and reducin" the adult osquito populations around at=risk counities$

"ackground

Zika virus is a osquito=borne flavivirus closely related to den"ue virus$ +t &as first isolated fro a rhesus onkey inZika forest! U"anda in 1'()! in osquitoes -Aedes africanus/ in the sae forest in 1'( and in huans in >i"eria in 1'($

Zika virus is endeic in parts of Africa and Asia and &as first identified in the *outh 5acific after an outbreak on ,ap

+sland in the Federated *tates of .icronesia in 200)$-1/

(ransmission

Zika virus is priarily transitted to huans throu"h bites fro Aedesosquitos! &hich often live around buildin"s inurban areas and are usually active durin" dayli"ht hours -peak bitin" activity occurs in early ornin"s and late

afternoons/$

*oe evidence su""ests Zika virus can also be transitted to huans throu"h blood transfusion! perinatal transission

and seile virus$ .ost people fully recover &ithout severe coplications! and hospitali;ation rates are lo&$ %o date! there

have been no reported deaths associated &ith Zika virus$

3iagnosis

*everal ethods can be used for dia"nosis! such as viral nucleic acid detection! virus isolation and serolo"ical testin"$

>ucleic acid detection by reverse transcriptase=polyerase chain reaction tar"etin" the non=structural protein "enoic re"ion is the priary eans of dia"nosis! &hile virus isolation is lar"ely for research purposes$ *aliva or urine

saples collected durin" the first 3 to days after sypto onset! or seru collected in the first 1 to 3 days! are

suitable for detection of Zika virus by these ethods$ *erolo"ical tests! includin" iunofluorescence assays anden;ye=linked iunosorbent assays ay indicate the presence of anti=Zika virus +". and +"B antibodies$ 4aution should

be taken &ith serolo"ical results as +". cross reactivity &ith other flaviviruses has been reported in both priary

infected patients and those &ith a probable history of prior flavivirus infection$

(reatment

%here is no coercial vaccine or specific antiviral dru" treatent for Zika virus infection$ %reatent is directed

priarily at relievin" syptos usin" anti=pyretics and anal"esics$

/revention and control

%he pro


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asic precautions for protection fro osquito bites should be taken by people travelin" to hi"h risk areas$ %hese include

use of repellents! &earin" li"ht colored! lon" sleeved shirts and pants and ensurin" roos are fitted &ith screens to

prevent osquitoes fro enterin"$

3isease outbreaks

%he first docuented outbreak of Zika virus in the *outh 5acific occurred on ,ap +sland in the Federated *tates of

.icronesia in 200)$ -1/%his outbreak affected 10 -confired! probable and suspected/ people and &as characteri;ed byrash! con#unctivitis and #oint pain$

+n ctober 2013! French 5olynesia reported its first outbreak! &hich &as estiated to affect around 11 of thepopulation$ -2/%his particular outbreak spread to other 5acific +slands includin" >e& 4aledonia! 4ook +slands! and 9aster

+sland$ As ost cases of Zika virus infection present &ith ild illness siilar to other circulatin" arbovirus infections!

and there &as liited laboratory capacity durin" this outbreak for the detection of Zika virus! it is likely that any cases

of infection &ere not identified$

4ore about disease vectors

oth Ae$ ae"yptiand Ae$ albopictushave been iplicated in lar"e outbreaks of Zika virus$ Ae$ ae"yptiis confined to

tropical and sub=tropical re"ions! &hile Ae$ albopictuscan be found in tropical! sub=tropical and teperate re"ions$ Ae$

albopictushas spread fro Asia and becoe established in areas of the *outh 5acific! Africa! 9urope and the Aericas

in recent decades$ +n the *outh 5acific!Ae$ hensilli&as iplicated in the spread of Zika virus on ,ap +sland in

200)! -1!3/&hile Ae$ polynesiensis&as suspected to spread Zika virus in French 5olynesia in 2013$ -2/>either of these

endeic species had been reco"ni;ed as a Zika virus vector before! indicatin" that as this eer"in" disease spreads topreviously unaffected countries! the potential e


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United ?epublic of %an;ania$ utbreaks of Zika virus disease have been recorded in Africa! the Aericas! Asia and

the 5acific$

Benre: Flavivirus

Lector: Aedes osquitoes -&hich usually bite durin" the ornin" and late afternoon7evenin" hours/

?eservoir: Unkno&n

.igns and .ymptoms

%he incubation period -the tie fro e


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Zika virus disease: Muestions and ans&ers

nline MA20 January 2016

Where does Zika virus occur?

Zika virus occurs in tropical areas &ith lar"e osquito populations! and is kno&n to circulate in Africa! the Aericas!

*outhern Asia and 8estern 5acific$

Zika virus &as discovered in 1'()! but for any years only sporadic huan cases &ere detected in Africa and

*outhern Asia$ +n 200)! the first docuented outbreak of Zika virus disease occurred in the 5acific$ *ince 2013!

cases and outbreaks of the disease have been reported fro the 8estern 5acific! the Aericas and Africa$ Biven the

e


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How is Zika virus disease treated?

%he syptos of Zika virus disease can be treated &ith coon pain and fever edicines! rest and plenty of &ater$

+f syptos &orsen! people should seek edical advice$ %here is currently no cure or vaccine for the disease itself$

How is Zika virus disease diagnosed?

For ost people dia"nosed &ith Zika virus disease! dia"nosis is based on their syptos and recent history -e$"$

osquito bites! or travel to an area &here Zika virus is kno&n to be present/$ A laboratory can confir the dia"nosisby blood tests$

What can I do to protect myself?

%he best protection fro Zika virus is preventin" osquito bites$ 5reventin" osquito bites &ill protect people fro

Zika virus! as &ell as other diseases that are transitted by osquitoes such as den"ue! chikun"unya and yello& fever$

%his can be done by usin" insect repellentD &earin" clothes -preferably li"ht=coloured/ that cover as uch of the body

as possibleD usin" physical barriers such as screens! closed doors and &indo&sD and sleepin" under osquito nets$ +t is

also iportant to epty! clean or cover containers that can hold &ater such as buckets! flo&er pots or tyres! so that

places &here osquitoes can breed are reoved$

.hould I avoid travelling to areas where Zika virus is occurring?

%ravellers should stay infored about Zika virus and other osquito=borne diseases and consult their local health or

travel authorities if they are concerned$

%o protect a"ainst Zika virus and other osquito=borne diseases! everyone should avoid bein" bitten by osquitoes by

takin" the easures described above$ 8oen &ho are pre"nant or plannin" to becoe pre"nant should follo& this

advice! and ay also consult their local health authorities if travellin" to an area &ith an on"oin" Zika virus outbreak$

ased on available evidence! 8 is not recoendin" any travel or trade restrictions related to Zika virus disease$As a precautionary easure! soe national "overnents ay ake public health and travel recoendations to their

o&n populations! based on their assessents of the available evidence and local risk factors$

What is WH) doing?

%o help countries prepare for and respond to Zika! 8 is &orkin" &ith inistries of health to iprove laboratory

capacity to detect the virus! providin" recoendations for clinical care and follo&=up of infected patients -in

collaboration &ith national professional associations and e

zika virus infection and zika fever

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