The prevalence of
hepatitis E virus (HEV) infection is strongly associated with HIV status,
results of a study conducted in Zambia and published in the online edition of
the Journal of Infectious Diseases
show. There was a 71% prevalence of HEV infection among HIV-positive adults,
compared to a prevalence of 24% in HIV-negative adults.
“HIV was strongly
associated with HEV status in adults,” comment the authors. “We suspect that
increased susceptibility is the likeliest explanation.”
There was also a
strong association between HEV infection and damage to gut mucosa.
HEV is one of the
leading causes of hepatitis globally and is associated with a high mortality
rate in pregnant women. The main mode of HEV transmission in resource-limited
setting is via faeco-oral contact, often due to use of contaminated water.
Individuals in settings with a high prevalence of HEV are also at risk of acquiring a number of other gut infections via contaminated water or poor
hygiene. This can cause damage to gut tissue, a condition often called
infection has been observed in people with HIV. Areas of high HIV and HEV
prevalence overlap, meaning that there is a risk of co-infection. However,
little is known about the prevalence of HEV infection in communities with a
high burden of HIV.
team of investigators therefore designed a study to determine HEV prevalence
among adults and children in the Misisi township, Zambia.
sample sets were used. Prevalence in
adults was analysed using blood samples collected in 1999. To assess prevalence
in children (aged one to 15 years), blood samples were collected in a prospective
study conducted in 2011.
All samples were
tested for antibodies to HEV (IgG, with positive samples also tested for IgM).
Gut tissue samples
were obtained from adults via biopsy to see if HEV infection was associated
with muscosal damage. Villous height, crypt depth and epithelial surface area
A total of 106
adults and 194 children were included in the study. None of the participants
Prevalence of HEV
antibodies in children increased with age, from 8% in those aged between one and four years to 36% in children aged ten to 14 years.
The prevalence of
HEV antibodies was higher in boys than girls (20 vs 13%). This difference was
not significant, but the authors note this finding is “consistent with the
higher attack rate in men in most epidemics”.
prevalence of HEV antibodies in adults was 42%. However, this differed
significantly according to HIV infection status, and was significantly higher
among HIV-positive individuals than HIV-negative individuals (71 vs 28%).
Analysis of risk
factors for HEV infection in children showed that storage of drinking water in
a closed container was associated with a non-significant reduction in the risk
of carrying HEV antibodies. The investigators believe this finding “suggests
that poor quality drinking water does increase HEV transmission in children”.
In adults, being
HIV positive was strongly associated with infection with HEV (OR = 8.4; 95% CI,
3.0-23.0; p = 0.0001).
between HEV infection and damage to gut mucosa was then explored. Villous
height was lower and crypt depth higher in adults positive for HEV antibodies.
There was evidence
of an interaction with HIV. Villous depth was significantly lower among
HIV-positive adults than HIV-negative adults (p = 0.04). Crypt depth was also
significantly higher in those with HIV (p = 0.0001).
“HEV and HIV are
both associated with similar changes in villous height and crypt depth, and
both are associated with non-significant reductions in epithelial surface
area,” write the authors.
analysis to people with HIV showed that HEV infection was associated with
greater crypt depth but not villous height. “It is likely that larger studies
may be required to resolve the relative ‘contributions’ of these two viruses,”
suggest the investigators.