Download Acquired Immune Deficiency Syndrome (AIDS)

AcquiredImmuneDeficiencySyndrome(AIDS)
ByJenniferOsita
Disease
ThediseaseIamstudyingisAIDS(AcquiredImmuneDeficiencySyndrome)whichiswhentheimmune
systemistooweaktofightoffmanyinfections. (1)
Etiologicagent
TheetiologicagentforAIDSisHIV(Humanimmunodeficiencyvirus)whichiswhenthevirusdestroysa
typeofwhitebloodcellcalledaT-helpercellandmakescopiesofitselfinsidethem.T-helpercellsare
alsoreferredtoasCD4cells.(1)
Transmission
HIVisspreaddirectlyfrompersontopersonthroughcertainbodyfluids-blood,semen(cum),preseminalfluid(pre-cum),rectalfluids,vaginalfluids,andbreastmilk.Thesefluidsmustcomeincontact
withamucousmembraneordamagedtissueorbedirectlyinjectedintothebloodstream(fromaneedle
orsyringe)fortransmissiontooccur.Mucousmembranesarefoundinsidetherectum,vagina,penis,
andmouth.HIVcanalsobespreadfrommothertochildduringpregnancy,birth,orbreastfeedingwhich
islesscommon.Lastlyreceivingbloodtransfusions,bloodproducts,ororgan/tissuetransplantsthatare
contaminatedwithHIV.ThiswasmorecommonintheearlyyearsofHIV,butnowtheriskisextremely
smallbecauseofrigoroustestingoftheUSbloodsupplyanddonatedorgansandtissues.(2)
Reservoirs
HIVisabletoremainachronic,life-longinfectionduetoitsabilitytostayhiddenwithininfectedblood
cells.LatentreservoirsofHIVarelocatedthroughoutthebody,includingthebrain,lymphoidtissue,
bonemarrow,andthegenitaltract.(3)
GeneralcharacteristicsofMicroorganism
HIVisaretroviruswithagenomeconsistingoftwoidenticalRNAmoleculeslinkedinadimericstructure.
RetrovirusesuseanenzymecalledreversetranscriptasetosynthesizeDNAthatisthenincorporated
intothegenomeofthehostcell,formingaprovirus.HIVbelongstoasubgroupknownaslentiviruses
(“slow”viruses)thathavealongperiodoftimebetweentheinitialinfectionandtheonsetofserious
symptoms.HIVisasphericalviruswithanenvelopecomprisedofalipidbilayerandsurface
glycoproteins,gp120andgp41,thatattachtohostcellreceptors,CD4andCCR5.(4)
Keytestsforidentification
HIVisdiagnosedbybloodtestsinvolvingtwoormorepositiveELISA(enzymelinkedimmunosorbent
assay)teststhathavebeenconfirmedbyaWesternblotassay.ThelevelofCD4+helperTcellsis
countedaswell.AnormalCD4+countis800-1200cells/mm3,butforpeoplewithHIVthecountis
usuallyunder350cells/mm3inHIVpatients.AIDSisgenerallyconsideredthestateatwhichtheCD4+
countdropsbelow200cells/mm3.(4)
Signsandsymptomsofdisease
DuringtheearlystagesofHIVsignsandsymptomsincludefever,chill,nightsweats,rash,muscleaches,
sorethroat,fatigue,swollenlymphnodes,andmouthulcers.Thenthevirusundergoesalatentphase
untilitbeginsitsprogressiontoAIDSwhomsignsandsymptomsincluderapidweightloss,pneumonia,
soresofthemouth,analandgenitals,memoryloss,depression,andotherneurologicdisorders,red,
brown,pink,orpurplishblotchesonorundertheskinorinsidethemouth,nose,oreyelids,recurring
feverorprofusenightsweats,extremeandunexplainedtiredness,prolongedswellingofthelymph
glandsinthearmpits,groin,orneck,anddiarrheathatlastsformorethanaweek.(5)
Historicalinformation
In1999,astrainofSIV(calledSIVcpz)wasfoundinachimpanzeethatwasalmostidenticaltoHIVin
humans.Themostcommonlyacceptedtheoryisthatofthe'hunter'.Inthisscenario,SIVcpzwas
transferredtohumansasaresultofchimpsbeingkilledandeaten,ortheirbloodgettingintocutsor
woundsonthehumanhunter.TheirstudiesconcludedthatthefirsttransmissionofSIVtoHIVin
humanstookplacearound1920inKinshasaintheDemocraticRepublicofCongo(DRCongo).Thearea
aroundKinshasaisfulloftransportlinks,suchasroads,railwaysandrivers.Italsohadagrowingsex
tradearoundthistime.ThehighpopulationofmigrantsandsextrademightexplainhowHIVspread
alongtheseinfrastructureroutes,firstlytoBrazzavilleby1937.(6)
Virulencefactors
HIVprimarilyattacksCD4+helperTcellsbyrecognizingandbindingtheCD4receptoronthesurfaceof
theTcells.ItcansometimesinvademonocytesandmacrophagesaswellsincetheyalsohavesomeCD4
receptorsontheirsurfaces.Tumornecrosisfactoralpha(TNF-a)andinterleukin-6(IL-6)aresecretedat
higherlevelsininfectedindividuals,andthismayhelpactivatetheHIVproviruses(latentviruses).HIV
hasahighmutationrateduringreplicationwiththereversetranscriptase,whichiswhyitisableto
readilyevadeourimmuneresponse.(4)
Control/Treatment
Oneproposederadicationstrategyistoactivatetheselatentlyinfectedcellsinthecontinuedpresence
ofHAART.Therationaleforthestrategyistwo-fold.Bystimulatinglatentlyinfectedcellstoreplicate
andexpressthevirus,suchcellswilldiemorerapidly[HIV-inducedcelldeath].Oncethecellular
reservoirsbeginproducingHIV,theinfectedcellswillberecognizedbytheimmunesystem.Thekeyto
thisstrategyisthesimultaneousadministrationofanactivatingagentconcurrentlywithHAART,and
perhapsothertherapiestopreventneworspreadinginfection.(3)
Prevention/Vaccineinformation,newtrials?
ThebestwaytopreventHIVistopracticesafesexandmakesureyouandyourpartner(s)aretested
annually.Also,donotshareneedles.ThereiscurrentlynovaccinethatwillpreventHIVinfectionortreat
thosewhohaveit.AstheleadNationalInstitutesofHealth(NIH)InstituteforHIVvaccineresearch,
NIAIDconductsand/orsupportsvaccineclinicalresearchprimarilythroughtheVaccineResearchCenter
andtheNIAID-sponsoredHIVVaccineTrialsNetwork.Todate,NIAIDhassupported143vaccinetrials
involving98differentproductsand27adjuvants.(7)
Localcasesoroutbreaks(withincidencefigures)
Anestimatednumberof73,959arelivingwithHIV/AIDSinTexasasof2016.Anestimatednumberof
931,526arelivingwithHIV/AIDSintheUnitedStates.(8).InTravisCountyalone,itissaidthatsomeone
ininfectedwithHIV/AIDSevery35hoursalone,andasofnowthetotalcountofpeoplelivingwiththis
diseaseisat4,138.(9)
Globalcasesoroutbreaks(withincidencefigures)
AccordingtoWorldHealthOrganizationtherewereapproximately36.9millionpeopleworldwideliving
withHIV/AIDSattheendof2015.Ofthese,2.6millionwerechildren(<15yearsold).Sub-SaharanAfrica
accountsforalmost70percentoftheglobaltotalofnewHIVinfections.(10)
References
1. "What Are HIV and AIDS? | AVERT." What Are HIV and AIDS? | AVERT. Web. 30
Apr. 2016.
2. "HIV Transmission." Centers for Disease Control and Prevention. Centers for
Disease Control and Prevention, 2015. Web. 30 Apr. 2016.
3. "Join the Alliance." AIDS Research Alliance: Eradicating HIV Reservoirs. Web. 30
Apr. 2016.
4. "HIV." HIV. Web. 30 Apr. 2016.
5. "Symptoms of HIV." Symptoms of HIV. Web. 30 Apr. 2016.
6. "Origin of HIV & AIDS | AVERT." Origin of HIV & AIDS | AVERT. Web. 30 Apr. 2016.
7. "Clinical HIV Vaccine Research." Clinical HIV Vaccine Research. Web. 30 Apr.
2016.
8. "AIDS." AIDS. Web. 30 Apr. 2016.
9. "Austin/ Travis County Health and Human Service Department." Health and
Human Service Department, 22 Apr. 2015. Web. 30 Apr. 2016.
10. "Global Statistics." Global Statistics. Web. 30 Apr. 2016.
Hyperlinks
1. http://www.avert.org/about-hiv-aids/what-hiv-aids
2. http://www.cdc.gov/hiv/basics/transmission.html
3. http://aidsresearch.org/cure-research/eradicating-hiv-reservoirs
4. http://web.uconn.edu/mcbstaff/graf/Student%20presentations/HIV/HIV.html
5. https://www.aids.gov/hiv-aids-basics/hiv-aids-101/signs-and-symptoms/
6. http://www.avert.org/professionals/history-hiv-aids/origin
7. http://www.niaid.nih.gov/topics/HIVAIDS/Research/vaccines/Pages/clinical.aspx
8. http://www.austincc.edu/microbio/2704y/hiv.htm
9. http://www.austintexas.gov/sites/default/files/files/Health/Info_to_Post/Critical_Health_In
dicators_2015.pdf
10. https://www.aids.gov/hiv-aids-basics/hiv-aids-101/global-statistics/