356 Introduction to Human Nutrition
forming the basis for the development of antiretrovi-
ral drugs to treat HIV/AIDS. More about this can be
found in the clinical nutrition textbook of this series
or at http://en.wikipedia.org/wiki/HIV.
Transmission of HIV
Because there is still no vaccine against HIV and no
cure available, the emphasis is on prevention of trans-
mission of the virus. It is transmitted from person to
person via certain body fl uids: blood (and blood
products), semen, pre-seminal fl uid, vaginal secre-
tions, and breast milk.
The majority of HIV infections are acquired
through unprotected sexual contact when sexual
secretions of one partner come into contact with
genital, oral, or rectal mucous membranes of another.
The estimated infection risk per 10 000 exposures
(without a condom) to an infected source varies from
0.5 to 50, depending on the type of exposure.
The blood transmission route is responsible for
infections in intravenous drug users when they share
needles with contaminated persons. Although blood
and blood products are these days mostly checked for
HIV, unhygienic practices in some developing coun-
tries, needle prick injuries of nurses and doctors, as
well as procedures such as tattoos, piercings, and
scarifi cation rituals pose some risk for infection.
Transmission of the virus from an infected mother
to her child can occur in utero during pregnancy,
during childbirth (intrapartum), or during breast-
feeding. The transmission rate between untreated
infected mothers and children is approximately 25%.
This risk can be reduced to 1% with combination
antiretroviral treatment of the mother and cesarean
section. The overall risk of a breastfeeding mother to
child is between 20% and 45%. Recent studies have
shown that this risk can be reduced three- to fourfold
by exclusive breastfeeding for up to 6 months. Exclu-
sive breastfeeding for 6 months is therefore the present
recommendation from the WHO for infected mothers
in developing countries “unless replacement feeding
is acceptable, feasible, affordable, sustainable and safe
for them and their infants before that time.”
The clinical course of HIV infection:
progression to AIDS
The different stages of HIV infection dictate different
types of nutritional intervention. Even before infec-
tion, the vicious cycle of undernutrition and poverty
in developing countries may increase vulnerability to
infection: the hopelessness and despair of poverty
could lead to alcohol abuse, violence, rape, and irre-
sponsible sexual behaviors, increasing exposure to the
virus. In addition, malnutrition could compromise
the integrity of the immune system, increasing vul-
nerability to infection. Breaking this cycle by appro-
priate public health nutrition interventions in poverty
alleviation programs may indirectly also impact on
HIV transmission.● Stage 1: Incubation period
There are no symptoms during this stage and its
duration is usually 2–4 weeks.
● Stage 2: Acute infection (seroconversion)
There is rapid viral replication during this stage. It
may last from a week to several months with a mean
duration of 28 days. The symptoms in this stage
include fever, lymphadenopathy, pharyngitis, rash,
myalgia, malaise, headache, and mouth and esoph-
ageal sores.
● Stage 3: Asymptomatic or latency stage
This stage may last from a few weeks up to 10 or 20
years, depending on the nutritional status and drug
treatment of the individual. It is characterized by
none or only a few symptoms, which may include
subclinical weight loss, vitamin B 12 defi ciency,
changes in blood lipids and liver enzymes, and an
increased susceptibility to pathogens in food and
water.
● Stage 4: Symptomatic HIV infection
CD4+^ cell counts (the immune cells containing the
CD4 receptor, which binds the virus and which is
destroyed during viral replication) have decreased
from normal values of 1200, to between 200
and 500 cells/μl. Wasting is a characteristic symptom
and is defi ned as an involuntary loss of more
than 10% of baseline body weight. Other symptoms
include loss of appetite, white plaques in the
mouth, skin lesions, fever, night sweats, TB,
shingles, and other infections. Nutrition interven-
tions may help to preserve lean body mass,
“strengthen” the immune system and slow progres-
sion to stage 5.
● Stage 5: AIDS
The CD4+ counts are now below 200 cells/μL. The
immunosuppression is severe and leads to many
possible opportunistic or secondary infections with
fungi, protozoa, bacteria and/or other viruses.