AIDS Ch5 Epidemiology

8/19/2019 AIDS Ch5 Epidemiology

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CHAPTER 5

The Epidemiology of AIDS


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Epidemiology

WHO definition:

• Epidemiology is the study of the distriution !nd

determin!nts of he!lth"rel!ted st!tes or e#ents $in%luding

dise!se&' !nd the !ppli%!tion of this study to the %ontrol of

dise!ses !nd other he!lth prolems(

•)!rious methods %!n e used to %!rry out epidemiologi%!l

in#estig!tions: sur#eill!n%e !nd des%ripti#e studies %!n e

used to study distriution* !n!lyti%!l studies !re used tostudy determin!nts(


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AIDS !nd Epidemiology

In +une ,-.,' do%tors !t the CDC:

– Described five cases of Pneumocystis pneumonia in homosexual men inLos Angeles. – Received several requests for pentamidine isethionate, which is used to

treat Pneumocystis pneumonia. – Received reports of an unusual number of cases of Kaposi’s sarcoma and

suppressed immune sstems in patients(

/y the end of ,-.0' epidemiologists h!d n!med the dise!se

!%1uired immune defi%ien%y syndrome $AIDS&( – !urmised that there was a common denominator among cases in separate

populations.

– As data on the long incubation period emerged, the guessed a larger

group was infected and would manifest smptoms in the future.

– "sed case control studies to gather additional data.


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A %!se"%ontrol study is !n !n!lyti%!l study 2hi%h %omp!res

indi#idu!ls 2ho h!#e ! spe%ifi% dise!se $3%!ses3& 2ith !

group of indi#idu!ls 2ithout the dise!se $3%ontrols3&( Theproportion of e!%h group h!#ing ! history of ! p!rti%ul!r

e4posure or %h!r!%teristi% of interest is then %omp!red(


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Epidemiologists g!thered enough d!t! to prep!re ! %!se

definition for AIDS in ,-.(

– 6!de re%ommend!tions for !#oiding the dise!se(

– Physi%i!n reporting pointed to lood !nd semen !s

prin%ip!l sour%es of the dise!se !gent(

C!se %ontrol studies en!led epidemiologists to sho2:

– 7umer !nd fre1uen%y of se4u!l p!rtners !mong

homose4u!l men 2ere f!%tors in the in%iden%e of AIDS(

– Se4u!l p!rtners of homose4u!l !nd ise4u!l men 2ere

!t ris8 !nd th!t more th!n 09 of %!ses o%%urred in

men 2ho h!d ! se4u!l rel!tionship 2ith !n infe%ted

person(


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HI) #irus(

– Disintegr!tes outside the ody( – C!nnot resist en#ironment!l pressures(

Tr!nsmission re1uires e4%h!nge of ody fluids to spre!d

– A l!rge numer of #ir!l p!rti%les must e p!ssed during

tr!nsmission(

– P!rti%le %ounts in s!li#!' te!rs' !nd s2e!t !re too lo2 to

!ffe%t HI) tr!nsmission(

Semen !nd lood rem!in the m!;or

tr!nsferring sust!n%es of HI)(

Other %ontriuting ris8 f!%tors: – )olume of fluid introdu%ed into

the re%ipient(

–


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35.3million [32.2 million – 38.8 million]32.1million [29.1 million – 35.3 million]

17.7million [16.4 million – 19.3 million]



2.0 million [1.7 million – 2.4 million]

260000]230000–320000[


1.4 million [1.2 million – 1.7 million]

210000]190000–250000[

Number of people living wit !"#

$eople newl% infe&te' wit !"# in 2012

(")* 'e+t, in 2012

-ot+l('ult,

omen

/il'ren 15 %e+r,

-ot+l

('ult,

/il'ren 15 %e+r,

-ot+l

('ult,

/il'ren 15 %e+r,

Global summary of the AIDS epidemic 2012

WHO, UNAIDS, UNICEF 2014


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Total: 35.3 million [32.2 million – 38.8 million]

Western&Central Europe

860000]800000–930000[

Middle East & Nort !"ri#a260000

]200000–380000[

$u%$aaran !"ri#a25.0million

[23.5million – 26.6 million]

Eastern Europe& Central !sia

1.3million[1.0million – 1.7 million]

$out & $outEast !sia3.9million


'#eania51000

]43000–59000[

Nort !meri#a1.3million

[980000–1.9million]

(atin !meri#a1.5million


East !sia880000

[650000–1.2million]

Cari%%ean

250000]220000–280000[

Adults and children estimated to be living with HI 2012



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Epidemi% in the =nited St!tes

CDC MMWR +une ,5' 09,0: Estim!ted numer of persons !ged >, ye!rs li#ing

2ith di!gnosed !nd undi!gnosed HI) infe%tion? !nd per%ent!ge 2ith undi!gnosedHI) infe%tion@ 7!tion!l HI) Sur#eill!n%e System' =nited St!tes' ,-.5B099.

# $%& prevalence estimates were based on national $%& surveillance data for persons aged '() ears at diagnosis

reported through *une +( using extended bac-calculation.

/ 0he number of undiagnosed $%& infections was calculated b subtracting the estimated number of diagnosed $%&

infections in living persons from the estimated overall $%& prevalence.


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Epidemi% in the =nited St!tes

• (.) million

Americans had been

diagnosed with

A%D! or found to be

$%&positive in

+1.• Rates of new $%&

infections and deathsfrom A%D! have not

significantl

changed in the ".!.

since (223.

• 4radual shift awa

from sexuall activehomosexual men and

toward blac-s,

$ispanics, and

women.


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!reas )it te i*est estimated rates o" persons

li+in* )it dia*nosed ,- in"e#tion at te end o"

2/0/ )ere the District of Columbi !2,"04#$%, Ne&

'or( !)10#0%, the U#S# *ir+i Isl-s !.."#1%,

/rl- !.$2#%, Flori- !2#"%, 3uerto ico

!)4#$%, Ne& 5erse !4))#2%, 6ouisi !41#"%,- 7eor+i !42)#)%#


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Estim!ted 7e2 HI) Infe%tions in the =nited St!tes' 09,9' for

the 6ost Affe%ted Supopul!tions $CDC&

Estim!ted ne2 AIDS di!gnoses !s of

09,, y geogr!phi% distriution :

• South 5• 7orthe!st 0

• West ,-• 6id2est ,


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Annu!l Pre#!len%e of Adults i#ing 2ith HI) Dise!se'

,--5"09,0' lorid!

As result of -eclii+ -eths, ul HI*8AIDS -i+oses h9e e:cee-e- -eths sice 1,

- the umber of ;ersos re;orte- &ith HI*8AIDS tht re ;resume- to be li9e hs bee

icresi+# Sice the er 1, ;re9let cses h9e icrese- b 4.)


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3o;ultio EstimtesN=1.,10,)42

6i9i+ A-ult HI*8AIDS CsesN=),21

Note> I this s;shot of li9i+ -ult HI*8AIDS cses throu+h 2012, 4< re blc(, &heresol 14< of Flori-?s -ult ;o;ultio re blc(# @his i-ictes -is;rit of HI*8AIDS i the blc(;o;ultio#

Source> 3o;ultio estimtes re ;ro9i-e- b Flori-CHA@SOther iclu-es Asi83cific Isl-ers - Nti9e Als(s8Americ I-is#

Adults i#ing 2ith HI) Dise!se' !nd

St!te Popul!tion?' y R!%eFEthni%ity'

Reported through 09,0' lorid!


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3ersos 6i9i+ &ith HI* Diseseb Selecte- Demo+r;hics - is( Fctors

U#S# !2010% - Flori- !2012%

Note> />F rtio> U#S#, $#0>1# F6, 2#4>1

Source> U#S# -t> HI* Sur9eillce e;ort, 2011 !most recet 9ilble% *ol# 2$, @ble 1 !HI*

-t for ll 0 sttes% htt;>88&&c-c#+o98hi98to;ics8sur9eillce8resources8re;orts8i-e:#htm

Flori- -t> F6 De;rtmet of Helth, HI*8AIDS - He;titis Sectio, li9e - re;orte- throu+h

2012, s of 0.8$081$#

http://www.cdc.gov/hiv/topics/surveillance/resources/reports/index.htmhttp://www.cdc.gov/hiv/topics/surveillance/resources/reports/index.htmhttp://www.cdc.gov/hiv/topics/surveillance/resources/reports/index.htm


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HI) !nd AIDS in 2omen

Women represent 09 of !ll di!gnoses of HI) infe%tion in the

=nited St!tes (!pread of $%& through highris- heterosexual contact is on the rise because

women are more susceptible than men to the spread of $%& through

heterosexual activit, and most sex events in the human population are

heterosexual.

• !uggests that $%& distribution in the ".!. ma become predominantl heterosexual and female.

Pre#ention %h!llenges for 2omen

• "naware of partner’s ris- factors for $%& infection.• Relationship dnamics 5fear of phsical abuse or abandonment if the

insist on condom use6• $istor of sexual abuse ma lead to the use of drugs as a coping

mechanism.• 7a exchange sex for drugs or engage in highris- sexual activities.


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)!gin!l infe%tions• 8acterial vaginosis increases a woman’s susceptibilit to $%& infection

because it interferes with the normal metabolism of cells lining the vaginal

cavit.

• 9pportunistic diseases are equall prevalent in $%&infected women andmen 5except for cervical cancer and Kaposi’s sarcoma6

• 4necological complications associated with !0Ds require special attention

HI* - AIDS i &ome

HI) infe%tion !nd pregn!n%y

• $AAR0 or even A:0 intervention can interrupt viral passage to the fetus.

• During deliver, an obstetrician will postpone rupture of the amniotic

membranes or other potentiall invasive procedures that might encourage

$%& transmission.


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HI) !nd AIDS in in;e%tion drug users

• !haring of bloodstained needles and sringes• Rinsing the syringe !nd needle in ! le!%h solution %!n elimin!te the

#irus !nd interrupt tr!nsmission(

• !haring needles and sringes that contain a drugblood mixture that is not

entirel removed before use b the next person.• In 09,9' - of HI) infe%tions 2ere !ttriut!le to the use of in;e%tion

drugs(

eg!l needle e4%h!nge progr!ms

• ;ot available in all states.• ;eedles and sringes ma still be hard to come b.• African Americans.

• AIDS epidemi% is gr!du!lly t!8ing on so%iologi%!l' politi%!l' !nd

e%onomi% o#ertones th!t differ from those of the p!st(


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The Spre!ding Epidemi% in the =nited St!tes

? E!rly high pre#!len%e of HI) in the !%ti#e homose4u!l

popul!tion suggests th!t HI) entered the =(S( homose4u!lpopul!tion #ery e!rly in the epidemi% here(

?

HI) in the =(S(

? CDC re%ommends !nnu!l HI) testing for men 2ho h!#e se42ith men(

? Tr!nsgender %ommunities in the =(S( !re !mong the groups !t highest ris8

for HI) infe%tion(

• 0ransgender refers to individuals who do not conform to the traditional

definition of gender based on external genitalia or their sex assigned at

birth.• %dentifing transgender people can be challenging.• $igh levels of $%& ris- behavior have been reported among transgender

people.


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HI) !nd AIDS in g!y !nd ise4u!l men !nd

tr!nsgender indi#idu!ls


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HI) !nd AIDS in heterose4u!ls

@or heterosexuals, the ris- of contracting A%D! can be substantial, depending

on circumstances.

HI) ris8s from heterose4u!l inter%ourse: fem!les

• ounds, lesions, or abrasions along the vaginal lining.• &irus can pass through the lining of the uterus if vaginal intercourse

occurs at the beginning of or during a woman’s menstrual period.

• 7acrophages ma also be able to pass through the tissue of the cervix.HI) ris8s from heterose4u!l inter%ourse: m!les

• Lesions on the outside surface of the penis.• &iruses or infected 0lmphoctes can enter the urethra at the conclusion

of e=aculation.

Abstinence is the most sensible and efficient method of preventing $%&

transmission.

Bondom use and limiting the number of sexual partners are also recommended.


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In the ,-.9s' most di!gnosed older Ameri%!ns %ontr!%ted HI) !s ! result

of ! %ont!min!ted lood tr!nsfusion(

• Burrentl, the vast ma=orit have become infected as a result of

heterosexual contact.

;umber of cases and deaths in this group is expected to increase because of

new treatments that prolong life.

9bstacles include overcoming denial and stigma.

Aul 3re9lece of A-ult /les

6i9i+ &ith HI* Disese, b

Curret A+e, 1B2012, Flori-


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HI) !nd AIDS in %orre%tion!l

f!%ilities

– %ncarcerated men and women are

often first diagnosed with $%& in a

correctional setting.

– BDB recommends $%& screening

upon entr into prison and beforerelease, in addition to voluntar $%&

testing periodicall during

incarceration.

– 0esting hesitanc is common due tothe stigma associated with a positive

diagnosis and concern that

confidentialit will not be

maintained.


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HI) !nd AIDS in s%hools !nd %olleges

%ncidence in schoolage children and teenagers is rel!ti#ely lo2' but the potential

for exposure exists.

• Experimenting with drugs and sexualit is common.9bstacles

• %gnorance and feelings of invincibilit.

BDB is wor-ing on a multifaceted approach to interventions, including the use of

prevention messages on cell phones, gaming sstems, websites, and social media.

'ou+ ;eo;le +e- 1$ to 1 i the

U#S# re t hi+h ris( for HI*

ifectio !CDC 2011%#


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HI) !nd AIDS in ne2orns

Women %!n p!ss HI) to their !ies:

• During pregn!n%y(• During deli#ery(• Through re!st"feeding(

/y 099G' the CDC h!d reports of more th!n -'999 %umul!ti#e

%onfirmed %!ses of pedi!tri% AIDS in =S(

Testing of ne2orns e%!me possile 2ith the de#elopment of

the #ir!l lo!d test(

7e2 HI) infe%tions !mong %hildren h!#e de%lined sin%e 099(6ore th!n -9 of the %hildren 2ho !%1uired HI) in 09,, li#e

in su"S!h!r!n Afri%!(


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Studies sho2 th!t r!pid implement!tion of AT tre!tment

%!n lo%8 tr!nsmission to the fetus(• ed to ! steep de%line of pren!t!lly !%1uired AIDS(

• =n%le!r 2hy these drugs !re more effe%ti#e in lo%8ing

the spre!d to the inf!nt %omp!red 2ith the effe%t on the!dult(

!ome newborns appeared to neutraliFe $%& before it became

entrenched in the tissues ? ;ow attributed to maternal antibodiesthat eventuall cleared the neonnates’ sstem, not genuine $%&

infection.


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Pedi!tri% AIDS

Symptoms

? !ilure to thri#e• Do not demonstrate expected growth patterns after birth.• Do not respond to aggressive nutritional therap.• Experience weight loss that does not reverse itself.• Decreased cognitive s-ills.

? C!ndidi!sis

? ymph!denop!thy

? S2ollen s!li#!ry gl!nds

? Opportunisti% dise!ses

– "suall have a bacterial source.• Salmonella species 5intestinal infections6

• !treptococci 5respirator infections6• !taphlococci 5s-in and blood infections6

? Only %ommon denomin!tor is ! %ompromised immune system(


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1600]1300–2000[


]14000–31000[




19000]16000–24000[

$out & $outEast !sia200000

]170000–270000[

'#eania3100

]2400–4100[

Nort !meri#a4500

]4000–5800[

(atin !meri#a40000

]32000–52000[

East !sia8200

]5800–11000[

Cari%%ean

16000 ]14000–19000[

!hildren "#1$ years% estimated to be living with HI 2012

Total: 3.3 million [3./ million – 3.1 million]


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Elimin!tion efforts

– In 099-' the +oint =nited 7!tions Progr!mme

on HI)FAIDS %!lled for the #irtu!l elimin!tion

of mother"to"%hild tr!nsmission $6TCT& of

HI)(

– In 09,9' the World He!lth Org!ni!tion $WHO&

pulished ! set of guidelines for est s%ientifi%'

progr!mm!ti% tools' !nd ne2 !d#i%e for s!ferinf!nt feed to elimin!te 6TCT(


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HI) !nd AIDS in Afri%!

• Dr!m!ti% in%re!ses in !ntiretro#ir!l ther!py %o#er!ge h!#e

o%%urred in su"S!h!r!n Afri%!(• Afri%! rem!ins the h!rdest"hit %ontinent(

– As mu%h !s G. of the 5 million people 2ith HI)

infe%tion or AIDS !re li#ing in su"S!h!r!n Afri%!

– Blaims ( million lives annuall in sub!aharan Africa.

Different p!ttern of spre!d th!n in Western Europe !nd the

=nited St!tes J 6ost tr!nsmissions t!8e pl!%e during

heterose4u!l #!gin!l inter%ourse(

• Attributed in part to lesions and sores from !0Ds.• Refusal to circumcise males also a contributing factor.• Bultural practice of Cdr sex in certain communities.• 0raditional attitudes against condom use.


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Total: 35.3 million [32.2 million – 38.8 million]


860000]800000–930000[


]200000–380000[




1.3million[1.0million – 1.7 million]

$out & $outEast !sia3.9million


'#eania51000

]43000–59000[

Nort !meri#a1.3million

[980000–1.9million]

(atin !meri#a1.5million


East !sia880000

[650000–1.2million]

Cari%%ean

250000 ]220000–280000[

Adults and children estimated to be living with HI 2012


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KSlim dise!seL – !mptoms include r!pid 2eight loss' intr!%t!le di!rrhe!' fe#er' !nd loss

of !ppetite(

– 7an patients are infe%ted 2ith the protoo!l p!r!sites Cryptosporidium and Isospora.

– HI) h!s !lso een lo%!ted in intestin!l m!%roph!ges, which ma reduce the

bod’s natural defenses.

• Other %onditions – Tuer%ulosis is the most pre#!lent opportunisti% dise!se in Afri%!( – Kaposi’s sarcoma is found in both infected and noninfected individuals. – Pneumocystis pneumonia is relativel rare.

• 0he epidemic is largel confined to urban

centers, where malaria is also widespread.


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World He!lth Org!ni!tion $WHO& !nd the =nited

7!tions Progr!m on AIDS $=7AIDS&

– Wor8 to promote physi%!l' ment!l' !nd so%i!l he!lth in

peoples of the 2orld(

– Colle%t !nd distriute d!t! on epidemi%s(

– Est!lish intern!tion!l progr!ms for de!ling 2ith epidemi%s(

St!tisti%s – )G million people worldwide live with $%&. – +12 countries are involved in the pandemic.

– Annual new $%& infections fell +(H between (22I and +(. –


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HI) !nd AIDS in the World

Se#er!l %ountries do not fit the de%lining trend(• Su"S!h!r!n Afri%!• E!stern Europe• Centr!l Asi!

The C!rie!n h!s the se%ond highest HI) pre#!len%e'

ut the epidemi% there h!s slo2ed signifi%!ntly sin%e

the mid",--9s(

In Asi!' pre#!len%e of HI) is !mong popul!tions !t

higher ris8 of infe%tion(


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Three m!;or p!tterns of tr!nsmission

Centr!l Europe

• Simil!r to th!t in the =nited St!tes' 2ith the

m!;ority of %!ses o%%urring in homose4u!l men

!nd in;e%tion drug users(

E!stern Europe' the Russi!n eder!tion' !nd =8r!ine

• In;e%tion drug use is the le!ding %!use(

!tin Ameri%! !nd su"S!h!r!n Afri%!

• Prim!rily tr!nsmitted y heterose4u!l %ont!%t(


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Indi!

– Se%ond to South Afri%! in the tot!l numer of %!ses of

HI) infe%tion !s of 099(

– Dise!se is highly stigm!tied(

Chin! – o2 in%iden%e' prim!rily from in;e%tion drug use(

– Con%erns !re rel!ted to the gro2ing se4 industry !nd

disd!in for %ondoms' !s 2ell !s %ont!min!ted lood

ot!ined !t %ommer%i!l %olle%tion %enters(


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WHO !nd =7AIDS

Committed to pre#enting ne2 HI) infe%tionsthrough:

• Edu%!tion

• /lood s%reening

• Tre!tment for in;e%tion drug users

See8 to ring support !nd %!re to the !ffli%ted 2hile

lin8ing together n!tion!l !nd intern!tion!l efforts tore!8 the %h!ins of tr!nsmission(

Documents

AIDS Ch5 Epidemiology