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8. Viral diseases
HIV infection and AIDS
– A I D S ( acq uired im m un e d eficien cy syn d rom e) is th e m ost severe form of H I V
in fection (hum an im m un od eficien cy virus).
– T w o subtyp es of H I V have been id en tified . H I V -1 is m ore w id esp read than H I V -
2,
w hich is m ain ly foun d in W est A frica. H IV -2 is less virulen t an d less tran sm issible
than H IV -1 .
– H IV affects the im m un e system by causin g a d eficit in C D 4 T lym p hocytes.
Evolution of the disease
– Primary infection or acute retroviral syndrome: 5 0 to 7 0 % of n ew ly in fected in d ivid uals
d evelop a viral syn d rom e (fever, m alaise, lym p had en op athy) d urin g serocon version
(from 1 5 d ays to 3 m on ths p ost exp osure).
– Asymptomatic HIV infection (after serocon version ): a p eriod of clin ical laten cy, but n ot
viral laten cy. T he tim e p eriod for p rogression from H IV in fection to the d evelop m en t
of severe im m un e d eficien cy in w estern coun tries is 1 0 years. T his p eriod ap p ears to
be shorter in d evelop in g coun tries.
– Symptomatic HIV infection: w ith p rogressive d estruction of th e im m un e system ,
com m on an d m ore severe d iseases occur m ore freq uen tly, an d w ith higher m ortality,
in serop ositive in d ivid uals.
– AIDS: this stage corresp on d s to the d evelop m en t of severe op p ortun istic in fection s an d
cneellso/pmlasmm .sW. F riothmoutatrbeioaltomgiecanl tpthoeindt iosfevaiseewp, rAogIrDessSesisradpeifdinlyetdowasaradCs dDea4th.coun t
below 2 0 0
3
WHO clinical staging of HIV/AIDS for ad ults an d ad olescen ts w ith 8
con firm ed H I V in fection .
T h e W H O h as p rop osed a clin ical classification of H I V in fection w ith 4 stages of
severity:
Clinical stage 1
A sym p tom atic
P ersisten t gen eraliz ed lym p had en op athy
Clinical stage 2
U n exp lain ed m od erate w eight loss (< 1 0 % of p resum ed or m easured bod y w eight)
R ecurren t resp iratory tract in fection s (sin usitis, ton sillitis, otitis m ed ia, p haryn gitis)
H erp es z oster
A n gular cheilitis
R ecurren t oral ulceration
P ap ular p ruritic erup tion s
S eborrhoeic d erm atitis
F un gal n ail in fection s
207
HIV infection and AIDS
– A I D S ( acq uired im m un e d eficien cy syn d rom e) is th e m ost severe form of H I V
in fection (hum an im m un od eficien cy virus).
– T w o subtyp es of H I V have been id en tified . H I V -1 is m ore w id esp read than H I V -
2,
w hich is m ain ly foun d in W est A frica. H IV -2 is less virulen t an d less tran sm issible
than H IV -1 .
– H IV affects the im m un e system by causin g a d eficit in C D 4 T lym p hocytes.
Evolution of the disease
– Primary infection or acute retroviral syndrome: 5 0 to 7 0 % of n ew ly in fected in d ivid uals
d evelop a viral syn d rom e (fever, m alaise, lym p had en op athy) d urin g serocon version
(from 1 5 d ays to 3 m on ths p ost exp osure).
– Asymptomatic HIV infection (after serocon version ): a p eriod of clin ical laten cy, but n ot
viral laten cy. T he tim e p eriod for p rogression from H IV in fection to the d evelop m en t
of severe im m un e d eficien cy in w estern coun tries is 1 0 years. T his p eriod ap p ears to
be shorter in d evelop in g coun tries.
– Symptomatic HIV infection: w ith p rogressive d estruction of th e im m un e system ,
com m on an d m ore severe d iseases occur m ore freq uen tly, an d w ith higher m ortality,
in serop ositive in d ivid uals.
– AIDS: this stage corresp on d s to the d evelop m en t of severe op p ortun istic in fection s an d
cneellso/pmlasmm .sW. F riothmoutatrbeioaltomgiecanl tpthoeindt iosfevaiseewp, rAogIrDessSesisradpeifdinlyetdowasaradCs dDea4th.coun t
below 2 0 0
3
WHO clinical staging of HIV/AIDS for ad ults an d ad olescen ts w ith 8
con firm ed H I V in fection .
T h e W H O h as p rop osed a clin ical classification of H I V in fection w ith 4 stages of
severity:
Clinical stage 1
A sym p tom atic
P ersisten t gen eraliz ed lym p had en op athy
Clinical stage 2
U n exp lain ed m od erate w eight loss (< 1 0 % of p resum ed or m easured bod y w eight)
R ecurren t resp iratory tract in fection s (sin usitis, ton sillitis, otitis m ed ia, p haryn gitis)
H erp es z oster
A n gular cheilitis
R ecurren t oral ulceration
P ap ular p ruritic erup tion s
S eborrhoeic d erm atitis
F un gal n ail in fection s
207
