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

Parasitology Section
Studies on the Epidemiology and Treatment
of Amoebiasis in Hué, Vietnam
Zusammenfassung
Hué, eine Stadt mit etwa 300 000 Einwohnern in
Zentralvietnam, gilt als ein “hot spot” für Erkrankungen
durch Entamoeba histolytica und insbesondere
von Amöbenleberabszessen (ALA). Daher eignet
sich dieser Ort in hervorragender Weise für Studien
zur Epidemiologie und Behandlung von E. histolytica-Infektionen.
Entsprechend wurden in den vergangenen
Jahren in enger Zusammenarbeit mit dem
Hué Medical College, dem Hué Central Hospital und
dem Bernhard-Nocht-institut für Tropenmedizin verschiedene
Studien zu diesem Thema in Hué durchgeführt.
Diese umfassten (i) die ausführliche Analyse
einer Vielzahl von Fällen mit ALA, (ii) parasitologische
und seroepidemiologische Feldstudien zur
Prävalenz von E. histolytica-Infektionen, sowie (iii)
vergleichende randomisierte Behandlungsstudien
zur Optimierung des therapeutischen Vorgehens bei
ALA und bei asymptomatischen E. histolytica-Infektionen.
Summary
Hué, a city of about 300,000 inhabitants in Central Vietnam,
is known as a ”hot spot” for diseases caused by
Entamoeba histolytica and in particular for amoebic
liver abscess (ALA), thus representing an excellent site
for studies on the epidemiology and treatment of E. histolytica
infections. Accordingly, during the last few
years, various studies on this topic have been performed
in Hué in close collaboration between the Hué
Medical College, the Hué Central Hospital and the
Bernhard Nocht Institute for Tropical Medicine. These
comprised (i) a comprehensive retrospective analysis of
large numbers of ALA cases, (ii) parasitological and
seroepidemiological surveys on the prevalence of E.
histolytica infection as well as (iii) comperative randomized
treatment trials to optimize the therapeutic regimen
for ALA and for asymptomatic E. histolytica infection.
Introduction
Entamoeba histolytica, the causative agent of human
amoebiasis, is endemic in most tropical and subtropical
countries and is considered responsible for millions of
cases of dysentery and liver abscess each year. Despite
its medical importance there is a considerable lack of
knowledge about the epidemiology of the parasite. The
recent identification of Entamoeba dispar as a separate
but nonpathogenic species, which is morphologically
indistinguishable from E. histolytica has called into
question most of the earlier data on the worldwide
prevalence of E. histolytica and its importance as a hu-
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man pathogen. Accordingly, the World Health Organization
has recommended reinforced efforts for reassessment
of the epidemiology and treatment of amoebiasis.
In this regard we have performed a series of studies in
Hué in Central Vietnam. Hué is the third largest city of
Vietnam and the capital of the province Thua Thien Hué
(TT Hué) (Fig. 1). In recent years, the region around
Hué City has been identified as an area of extraordinary
high incidence for amoebic liver abscess (ALA). Several
hundred cases of ALA are treated in the Central Hospital
of Hué every year, and a large proportion of the population
is considered infected with E. histolytica. Thus,
Hué represents an excellent site for studies on the epidemiology
and treatment of amoebaisis.
Figure 1: The province of Thua Thien Hué in Vietnam and its
nine districs. This province is located between the border to
Laos and the South China Sea and is flanked by the provinces
Quang Tri and Quang Nam.
Project Description and Results
Epidemiology of Amoebic Liver Abscess
To obtain more precise data on the epidemiology of
amoebic liver abscess (ALA) the hospital charts of all
ALA patients admitted to the Central Hospital of Hué
between 1900 and 1998 were analysed. This 8 years
period was chosen as it represents the time span when
the Central Hospital of Hué was the only medical care
unit within the whole province of TT Hué where ultrasound
was available. As ALA treatment in Central Vietnam
is generally performed by a combination of abscess
puncture and metronidazole therapy, the vast
majority of suspected ALA cases from the various parts
of the province were usually sent to the Central Hospital
of Hué. Only less severe cases of ALA may have been
treated with metronidazole alone and were not sent to
the hospital. According to the hospital charts, a total of
2031 cases of ALA were identified, indicating an overall
ALA incidence of at least 21 per 100,000 inhabitants
per year, which to our knowledge represents the highest
incidence of ALA on a regional level ever reported.