braz j infect dis.2014;18(2):177–180
The
Brazilian
Journal
of
INFECTIOUS
DISEASES
w w w . e l s e v i e r . c o m / l o c a t e / b j i d
Original
article
Pertussis
in
the
central-west
region
of
Brazil:
one
decade
study
Angelita
Fernandes
Druzian
a,∗,
Yvone
Maia
Brustoloni
b,
Sandra
Maria
do
Valle
Leone
Oliveira
b,
Vanessa
Terezinha
Gubert
de
Matos
b,
Adriana
Carla
Garcia
Negri
a,
Clarice
Souza
Pinto
c,
Silvia
Asato
c,
Cirlene
dos
Santos
Gonc¸alves
Urias
a,
Anamaria
Mello
Miranda
Paniago
baHospitalUniversitário,UniversidadeFederaldoMatoGrossodoSul(UFMS),CampoGrande,MS,Brazil bFaculdadedeMedicina,UniversidadeFederaldoMatoGrossodoSul(UFMS),CampoGrande,MS,Brazil cStateDepartmentofHealth,CampoGrande,MS,Brazil
a
r
t
i
c
l
e
i
n
f
o
Articlehistory:
Received17June2013
Accepted15August2013
Availableonline22November2013
Keywords: Whoopingcough Pertussis Epidemiology Bordetellapertussis Outbreakinvestigation
a
b
s
t
r
a
c
t
Inmanypartsoftheworld,numerousoutbreaksofpertussishavebeendescribeddespite
highvaccinationcoverage.Inthisarticlewereporttheepidemiologicalcharacteristicsof
pertussisinBrazilusingaSurveillanceWorksheet.Secondarydataofpertussiscase
inves-tigationsreportedfromJanuary1999toDecember2008recordedintheInformationSystem
forNotifiableDiseases(SINAN)andtheCentralLaboratoryforPublicHealth(LACEN-MS)
wereutilized.Thetotalof561suspectedcaseswerereportedand238(42.4%)ofthesewere
confirmed,mainlyinchildrenundersixmonths(61.8%)andwithincomplete
immuniza-tion(56.3%).Twooutbreaksweredetected.Mortalityraterangedfrom2.56%to11.11%.The
occurrenceofoutbreaksandthepoorperformanceofculturesforconfirmingdiagnosisare
problemswhichneedtobeaddressed.Highvaccinationcoverageiscertainlyagoodstrategy
toreducethenumberofcasesandtoreducetheimpactofthediseaseinchildrenyounger
thansixmonths.
©2013 ElsevierEditoraLtda.Allrightsreserved.
Introduction
Pertussisis anacuteinfection oftherespiratory tract with
agrowing numberofpeople atriskofcontracting the
dis-easeinmanypartsoftheworld.1Evenafterthedecreasein
prevalencefollowingthe adventoftheDiphtheria,Tetanus,
Pertussis (DTP) vaccine, pertussis has remained a
signifi-cant public health problem. Globally, an estimated overall
∗ Correspondingauthorat:RuaManoelLaburu,494,Apto14,BairroSãoLourenc¸o,CEP79041-310CampoGrande,MS,Brazil.
E-mailaddress:angelitadruzian@yahoo.com.br(A.F.Druzian).
annual incidence of 50 million cases, 95% of them in
developing countries,1 and approximately 300,000 deaths
have been causedbythis disease, withamortality rateof
around 1%indevelopingcountriesand 0.04%indeveloped
countries.2
Inmanypartsoftheworld,numerousoutbreaksof
pertus-sishavebeendescribeddespitehighvaccinationcoverage.3–5
Inthisarticle,wereporttheepidemiologicalcharacteristicsof
pertussisinthestateofMatoGrossodoSul,Brazil.
1413-8670/$–seefrontmatter©2013 ElsevierEditoraLtda.Allrightsreserved.
178
braz j infect dis.2014;18(2):177–180Materials
and
methods
This descriptive, cross-sectional and retrospective study
includedallPertussisSurveillanceWorksheetusedfrom
Jan-uary 1999 to December 2008 toreport pertussis suspected
casestotheHealthDepartmentoftheStateofMatoGrosso
doSul,Brazil.Thedatawerecollectedfromworksheetsafter
localinstitutionalreviewboardapproval.
TheBrazilianvaccinationschemeagainstBordetella
pertus-sisiscomposedbythreedosesattwo,fourandsixmonths
withthefirstboosterat6to12monthsafterthethirddose
andsecondboosteratfourtosixyears.6
Itwasused theterms establishedbythe Brazilian
Min-istryofHealth6forthecasedefinition.Suspectedcase–every
individualpresentingdrycoughfor14daysormore
associ-atedwithoneormoreofthefollowingsymptoms:paroxysmal
cough–sudden uncontrollablecough,with 5–10quickand
shortcoughsinasingleexhalation;inspiratorywhoop,
post-coughvomiting;orhavingahistoryofcontactwithapertussis
caseconfirmedbyclinicalcriteria.
Confirmed case: (a) by laboratorial criteria: isolation of
Bordetella pertussis;(b) byepidemiological criteria: any
sus-pectedcasewhichhashadcontactwithapertussisconfirmed
case by laboratory testing, between the beginning of the
catarrhal period up to three weeks after onset of the
diseaseparoxysmalperiod;(c)byclinicalcriteria:every
sus-pectedcaseofpertussiswhosehemogramshowsleukocytosis
(over 20,000leukocytes/mm3) and absolute lymphocytosis
(over10,000leukocytes/mm3)andnegativeornotperformed
culture;andabsenceofepidemiologicallinkage;andno
con-firmationofanotheretiology.
Excludedcase:anysuspectedcasethatdoesnotconform
toanyofthepreviouslydescribedcriteriaforconfirmedcases.
Theincidenceratewascalculatedbasedonthepopulation
estimatedbytheBrazilianInstituteofGeographyand
Statis-tics(IBGE)duringthestudyperiod.Statisticalanalyseswere
performedusingtheprogramEpiInfo3.5.1.
ThisstudywasapprovedbytheFederalUniversityofMato
GrossodoSulResearchEthicsCommittee,underprotocolno.
1147.
Results
Duringthe10yearsofthestudyperiod,theaverageof
per-tussisincidenceinMatoGrossodoSulwas1.07cases/100,000
populationandtheaverageofvaccinecoveragewas81.48%.
ThevaccineusedinBrazilisthewhole-cellpertussisvaccine
(WCVs).
Ofthe 561pertussis suspectedcasesthatwerereported
to the Health Department of the State ofMato Grosso do
Sul–Brazil,238(42.4%)wereconfirmedand281(50.1%)were
excluded.Noclassificationwasdefinedintheworksheetof42
(7.5%)casesandthesecaseswerenotconsideredasconfirmed
orexcluded.
Consideringtheconfirmedcases,132(55.5%)werefemale
and 106(44.5%)were male. Thehighestincidenceofcases
(61.8%)occurredbetweenzerotosixmonthsofage(Table1).
Amonginfectedchildren,contagionoccurredin134(56.3%)
casesbeforethepatienthadreachedtheagerecommended
0 20 40 60 80 100 120 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 Year
Reported Confirmed Vaccine coverage (%)
Total
ca
ses
Fig.1–Reportedandconfirmedpertussiscasesand percentageofvaccinecoverage,MatoGrossodoSul, 1999–2008.
fortheinitiationofthevaccinationschemeorshowed
incom-pleteimmunization(uptotwodoses).Fig.1demonstratesthe
distributionofreportedandconfirmedpertussiscasesduring
thestudyperiodandthepercentageofvaccinecoverageinthe
state.
Regarding the diagnostic confirmation criteria, 7.6%
(18/238)ofthepertussiscaseswereconfirmedbylaboratory
testing(positiveculture),22.7%(n=54/238)byepidemiologic
linkage(suggestiveclinicalprofileandcontactwithconfirmed
case),68.1%(162/238)byclinicalcriteria (suggestiveclinical
profileassociatedwithleukocytosisandlymphocytosis)and
the confirmation criteriawas notincluded inthe Pertussis
SurveillanceWorksheetof1.7%(n=4/238)cases.
Nasopharyn-geal secretion culture was collected of61 confirmed cases
patientsand18(29.5%)ofthesecultureswerepositive.
Twopertussisoutbreakswereobservedinthestatein2004
and2007.Fiftycaseswerereportedduringthefirstoutbreak
and11(22%)wereconfirmedwhile68caseswerereported
dur-ingthesecondoutbreakand12(17%)caseswereconfirmed.
Nopertussis-relateddeathsoccurredduringtheoutbreaks.
Five deaths occurred among the confirmed cases and
patients age rangedfrom 18 daysto threeyears.Thecase
fatalityratiooverthewhole10-yearperiodwas4.9%(4/82)in
childrenuptotwomonthsand0.9%(1/108)inchildrenolder
thantwomonths.Onlyonechildwasdiagnosedbypositive
Bordetellapertussisculture;theotherswereconfirmedby
clini-calcriteria.Thehighestmortalityrateof11.11%wasrecorded
in2000.Intheyears1999,2002and2008,mortalityrateswere
5.56%,4.46%and2.56%,respectively.
Discussion
Bordetella pertussis infection remains a serious problem to
childrennotimmunizedor withincompleteimmunization.
InPortoAlegre,54%ofchildrenwithpertussishadincomplete
vaccinationschedulewithonly0–2vaccinedoseshavingbeen
adminstered.7 The infection in these population suggests
that adults who have lost their vaccinal immunitycan be
importantsourcesofinfection.3,6
The higher incidence ofpertussis inchildren up to six
monthshasbeenalsodescribedbyotherBrazilianauthors.7,8
brazj infect dis.2014;18(2):177–180
179
Table1–Numberofvaccinedosesbyagegroupofpertussiscases,MatoGrossodoSul–Brazil,from1999to2008.
Agegroup N/% Numberofdoses
0 1 2 3 4ormore NR Upto2m 82/34.5 54 15 0 0 0 13 3–6m 65/27.3 15 21 14 1 0 14 7–11m 10/4.2 1 1 3 2 0 3 1–4y 33/13.9 2 4 1 9 11 6 5–9y 28/11.8 2 0 0 1 20 5 10–14y 10/4.2 0 1 0 0 6 3 15yormore 10/4.2 0 0 0 0 4 6 Total 238/100 74/31.1 42/17.6 18/7.6 13/5.5 41/17.2 50/21
Note:m,months;y,years;NR,notreported.
childrenyoungerthansixmonthsofageandinPortoAlegre 67.0%ofchildrenwithpertussiswereobservedtobeyounger thanoneyear.7
The USA pertussis incidence is lower than 1.0%. The
highvaccinationcoverageinchildrenbyagetwoyears has
resultedinhistoricallylowlevelsofmostvaccine-preventable
diseasesintheUnitedStates.Theestimatedvaccination
cov-erageamongchildrenaged19–35monthsrangedfrom95.0%
to96.2% accordingtothe NationalImmunizationSurveyof
the United States, 2007–2011.9 In Europe, the vaccination
coveragerangedfrom90.0%inFranceto100.0%inSweden.10
Ontheotherside,since2012UnitedKingdomfacesoutbreak
ofpertussisinunimmunizedyoungchildrenwithhighrates
ofmorbidityandmortality.5
Themajorityofpertussiscaseswereidentifiedbyclinical
criteria.Thesedataaresimilartoanotherstudyinthecountry,
where51%ofthecaseswere confirmedbyclinicalcriteria,
suchasclinicalprofile(26%)andsuggestiveWBC.11
Culture is considered the gold standard for pertussis
diagnosis and the only criteria forlaboratory confirmation
acceptedbytheBrazilianMinistryofHealth.6,12Among
differ-entstudies,positivityofculturesvariedfrom9.4%to78%.4,8
Inourstudy,nasopharyngealsecretionwascollectedinjust
25.6%(61/238).Thecultureofnasopharyngealsecretionwas
positivein29.5%(18/61)ofthesecases,highlightingthe
diffi-cultyinobtainingadefinitivediagnosis.Culturesensitivityis
influencedbyseveralfactors,includingthefastidiousnature
ofB.pertussis,thestageofthediseaseatwhichthecollection
wasmade,thevaccinationstatusoftheindividual,theprior
useofantibioticsandtransportconditionsofthesamples.12
Thegeographicaldistanceandthelogisticsofsending
sam-plesfromthecollectionsitetothelaboratorywherecultures
wereprocessedmayalsohaveinterferedinthelowpercentage
ofpositiveresults,sincetherewasasinglereference
labora-torytoperformall culturesinthestate.Performingculture
onallofthesuspectedcasesandPolymeraseChainReaction
(PCR)techniquePCRwould alsoaddtothe identificationof
cases.Moreover,thestatedoesnothavealaboratoryto
per-formthePCRforB.pertussisdetection.PCRwasadoptedby
manycountries toaidinlaboratory diagnosisand improve
pertusssissurveillance.11,13
The outbreaks observed in 2004 and 2007 occurred in
theperiodinwhichchildrenvaccinationcoverage wasless
than90%intheStatewhileBrazilianrateshaveremainedat
approximately80%forchildrenaged1–12.14Theimprovement
oftheepidemiologicalsurveillancesystemmayalsoexplain
thedetectionoftheoutbreaks.
Ofthefivereporteddeaths,similartotheresultofother
study,all ofthem occurred inchildrenand themajorityof
themwereyoungerthantwomonthsofage.Thehigh
mor-bidityaswellasseverity,increasedriskofcomplicationsand
mortalityinchildrenyoungerthansixmonthsarerecognized
factorsinvolvedinpertussis.15Thedetectionofpertussisover
aperiodof10yearsandtheevidenceoftwooutbreaks
demon-stratethatdiseaseisanimportantpublichealthproblemand
there is an evident risk of infection to children under six
months. Itis alsopossibleto havethe suspected casesgo
underreported.
Thedifficultyofdiagnosingpertussisbylaboratory
meth-odsseemstocollaboratetoturnthisintoaneglecteddisease
inthestate.Theimplementationofnewdiagnosticmethods,
suchasmolecularbiology techniques,could improvethese
results.Inthesameway,highvaccinationcoverageiscertainly
agoodstrategytoreducethenumberofcasesandtoreduce
theimpactofthediseaseinchildrenyoungerthansixmonths.
Conflicts
of
interest
Theauthorsdeclarenoconflictsofinterest.
Acknowledgements
TheauthorswouldliketothankStateDepartmentofHealth
(SES-MS)forprovidingthedatafromSystemforNotifiable
Dis-eases (SINAN)and theCentralLaboratoryforPublic Health
(LACEN-MS)forprovidinginformationaboutthecases.
R
e
f
e
r
e
n
c
e
s
1.GabuttiG,RotaMC.Pertussis:areviewofdiseases
epidemiologyworldwideandinItaly.IntJEnvironResPublic
Health.2012;9:4626–38.
2.WorldHealthOrganization(Geneva).Pertussisvaccines:WHO
positionpaper.WklyEpidemiolRec.2004;80:29–40.
3.SousaSG,BarrosH.PertussisemPortugal–Aimportânciade
umanovaestratégiavacinal.RevPortPneumol.
2010;16:573–88.
4.FismanDN,TangP,HauckT,etal.Pertussisresurgencein
180
braz j infect dis.2014;18(2):177–180test-incidencefeedbackmodeling.BMCPublicHealth.
2011;11:694.
5. AmirthalinganG.Strategiestocontrolpertussisininfats.
ArchDisChild.2013;98:552–5.
6. MinistériodaSaúde(BR).SecretariadeVigilânciaem
Saúde.GuiadeVigilânciaEpidemiológica.7thed.Brasília:
SVS;2010.
7. TrevizanS,CoutinhoSED.Perfilepidemiológicoda
coqueluchenoRioGrandedoSulBrasil:estudodacorrelac¸ão
entreincidênciaecoberturavacinal.CadSaudePublica.
2008;24:93–102.
8. BaptistaPN,MagalhaesVS,RodriguesLC.Childrenwith
pertussisinformtheinvestigationofotherpertussiscases
amongcontacts.BMCPediatr.2007;7:21.
9. CentersforDiseaseControl.Preventionnationalstatelocal
areavaccinationcoverageamongchildrenaged19–35
months—UnitedStates2011.MMWRMorbMortalWklyRep.
2012;61:689–712.
10.VanAmersfoorthSCM,SchoulsLM,VanderHeideHGJ,etal.
AnalysisofBordetellapertussispopulationsinEuropean
countrieswithdifferentvaccinationpolicies.JClinMicrobiol.
2005;43:2837–43.
11.MinistériodaSaúde(BR).SecretariadeVigilânciaemSaúde:
Núcleoshospitalaresdeepidemiologia:manualde
implantac¸ão.Brasília:SVS;2005.
12.SabellaC.Pertussis:oldfoe,persistentproblem.CleveClinJ
Med.2005;72:601–8.
13.MoraesJC,CarvalhanasT,BricksLF.Shouldacellular
pertussisvaccineberecommendtohealthcareprofessionals?
CadSaudePublica.2013;29:1277–90.
14.McCormickCM,CzachorJS.Pertussisinfectionsand
vaccinationsonBoliviaBrazilandMexicoform1980to2009.
TravelMedInfectDis.2013;11:146–51.
15.CampbellH,AmirthalingamG,AndrewsN,etal.Accelerating
controlofPertussisinEnglandandWales.EmergInfectDis.
