infection is often difficult to diagnose in very young children.
Infected babies, especially in the first few months of life, often
appear normal and may exhibit no telltale signs that would allow
a definitive diagnosis of HIV infection. Moreover, all children
born to infected mothers have antibodies to HIV, made by the mother's
immune system, that cross the placenta to the baby's bloodstream
before birth and persist for up to 18 months. Because these maternal
antibodies reflect the mother's but not the infant's infection status,
the test is not useful in newborns or young infants.
recent years, investigators have demonstrated the utility of highly
accurate blood tests in diagnosing HIV infection in children 6 months
of age and younger. One laboratory technique called polymerase chain
reaction (PCR) can detect minute quantities of the virus in an infant's
blood. Another procedure allows physicians to culture a sample of
an infant's blood and test it for the presence of HIV.
PCR assays or HIV culture techniques can identify at birth about
one-third of infants who are truly HIV-infected. With these techniques,
approximately 90 percent of HIV-infected infants are identifiable
by 2 months of age, and 95 percent by 3 months of age. One innovative
new approach to both RNA and DNA PCR testing uses dried blood spot
specimens, which should make it much simpler to gather and store
specimens in field settings.
of HIV Disease in Children
have observed two general patterns of illness in HIV-infected children.
About 20 percent of children develop serious disease in the first
year of life; most of these children die by age 4 years.
remaining 80 percent of infected children have a slower rate of
disease progression, many not developing the most serious symptoms
of AIDS until school entry or even adolescence. A recent report
from a large European registry of HIV-infected children indicated
that half of the children with perinatally acquired HIV disease
were alive at age 9. Another study, of 42 perinatally HIV-infected
children who survived beyond 9 years of age, found about one-quarter
of the children to be asymptomatic with relatively intact immune
factors responsible for the wide variation observed in the rate
of disease progression in HIV-infected children are a major focus
of the NIAID pediatric AIDS research effort. The Women and Infants
Transmission Study, a multisite perinatal HIV study funded by NIH,
has found that maternal factors including Vitamin A level and CD4
counts during pregnancy, as well as infant viral load and CD4 counts
in the first several months of life, can help identify those infants
at risk for rapid disease progression who may benefit from early
and Symptoms of Pediatric HIV Disease
children with HIV infection do not gain weight or grow normally.
HIV-infected children frequently are slow to reach important milestones
in motor skills and mental development such as crawling, walking
and speaking. As the disease progresses, many children develop neurologic
problems such as difficulty walking, poor school performance, seizures,
and other symptoms of HIV encephalopathy.
adults with HIV infection, children with HIV develop life-threatening
opportunistic infections (OIs), although the incidence of various
OIs differs in adults and children. For example, toxoplasmosis is
seen less frequently in HIV-infected children than in HIV-infected
adults, while serious bacterial infections occur more commonly in
children than in adults. Also, as children with HIV become sicker,
they may suffer from chronic diarrhea due to opportunistic pathogens.
carinii pneumonia (PCP) is the leading cause of death in HIV-infected
children with AIDS. PCP, as well as cytomegalovirus (CMV) disease,
usually are primary infections in children, whereas in adults these
diseases result from the reactivation of latent infections
lung disease called lymphocytic interstitial pneumonitis (LIP),
rarely seen in adults, also occurs frequently in HIV-infected children.
This condition, like PCP, can make breathing progressively more
difficult and often results in hospitalization.
with HIV suffer the usual childhood bacterial infections -- only
more frequently and more severely than uninfected children. These
bacterial infections can cause seizures, fever, pneumonia, recurrent
colds, diarrhea, dehydration and other problems that often result
in extended hospital stays and nutritional problems.
children frequently have severe candidiasis, a yeast infection that
can cause unrelenting diaper rash and infections in the mouth and
throat that make eating difficult.