Research Group Heussler (Malaria I) - Bernhard-Nocht-Institut für ...

Parasitology Section
Figure 4: Efficacy of paromomycin as compared with diloxanide furoate for the treatment of asymptomatic
E. histolytica infection.
the individuals had anti-E. histolytica serum antibodies.
Interestingly, in contrast to the sex distribution of ALA
patients, protozoan parasites including E. histolytica as
well as anti-amoebic antibodies were significantly more
prevalent in females, suggesting that gender related
factors or habits are important for the outcome of E.
histolytica infection. Analysis of household characteristics
and living conditions identified low level of education,
no access to a toilet or tapwater as well as the use
of river water to be important risk factors for E. histolytica
infection (Fig 3). Longitudinal follow-up of E. histolytica
carriers revealed a considerable period of parasite
persistance with a mean half-life of infection of more
than 1 year, which is in good agreement with clinical
observations indicating long latencies between infection
with E. histolytica and development of ALA.
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Treatment of Amoebiasis
The high number of ALA patients and of E. histolytica
carriers in Hué facilitated comprehensive studies on the
treatment of amoebiasis.
Treatment of ALA. In a prospective and randomized
trial, it was investigated whether ALA can be sufficiently
treated only with metronidazole or whether in addition
to the application of antibiotics, puncture and removal
of abscesses fluid is required, as it is necessary for bacterial
abscesses. Groups of patients with ALA of 6 to 10
cm located in the right liver lobe were included. The results
indicated that both therapeutic regimen are
equally effective. All abscesses were cured within the
observation period and there were no differences in the
time-courses of clinical improvement and abscess resolution,
which strongly support the concept that drug
treatment alone is sufficient to cure uncomplicated
ALAs.
Treatment of Asymptomatic E. histolytica Infection.
Paromomycin and diloxanide furoate are the drugs recommended
for the treatment of asymptomatic E. histolytica
infection. However, the efficacy of these medications
was evaluated before the identification of E.
dispar as a separate nonpathogenic species, which
does not require treatment. To determine the efficacy
of the two drugs for the treatment of E. histolytica
specifically, a randomized, comparative study was performed
in 72 asymptomatic carriers, which were identified
during our surveys in Phu Cat. Thirty-four subjects
were assigned to receive praromomycin and 37 sub-