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

For purposes of quality assurance parallel testing of
PCR specimens with the standard reference method is
carried out at BNITM, accordance rates of results are
>95 %, therefore the “field PCR” can be considered a
reliable method under tropical conditions. Preliminary
results also suggest an excellent diagnostic sensitivity
(>90 %) for early lesions.
In the context of the study more than 100 village health
workers have been trained in active case finding, diagnostic
specimens have been taken in the field and after
surgery, and tested at KCCR and BNITM with conventional
and molecular methods. Based on the results
and experiences from the ongoing study the framework
for diagnostic networks comprising peripheral and reference
level laboratories in endemic areas is being
elaborated. In order to establish correlations between
living environment (especially exposure to water bodies)
and the occurrence of BU the study patients are interviewed
by means of an epidemiological questionnaire.
Recently M.ulcerans has been detected by PCR
in various insects collected from water bodies in different
villages in the Agogo region, one of the major endemic
areas in Ghana.
A related study, designed to asses the effectiveness of
surgical treatment, is currently being carried out by
BNITM in collaboration with MSF, the Health District of
Akonolinga and Akonolinga Hospital, Cameroon, and
Agogo Hospital, Ghana. Presently the extent of the surgical
excision beyond necrotic tissue is merely determined
by the clinical experience of the operating surgeon
(Figure 2).
Figure 2: Excision tissue
As spread of infection beyond necrotic tissue can not
be excluded visually, the danger of relapses in the area
of the excised lesion due to insufficient excision margins
is high. Post-surgical assessment of excision margins
for the presence of M.ulcerans could help preventing
relapse cases, if patients with positive excision
margins were subsequently re-operated. Excised tissue
is subjected to PCR, culture and histopathological ana-
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Medical Microbiology Section
lysis in order to assess if the excision margins are free
of M.ulcerans and to determine up to which distance of
the edge of the ulcer bacilli and immunopathological
changes indicating progression of infection at the time
of surgical intervention can be detected (Figure 3).
Figure 3: Excision margins
Complete excision margins of 10 patients have been
tested, M.ulcerans was detected in 9 of those. Only the
excision margin of one nodule was completely free of
M.ulcerans. Long-term follow-up of the patients concerned
will establish the correlation between our findings
and the occurrence of recurrencies.
Funding
• Volkswagen Foundation
Cooperating Partners
• Ohene Adjei, Christof Berberich, Thomas Kruppa,
Kumasi Centre for Collaborative Research in
Tropical Medicine, Ghana
• William Thompson, Agogo Presbyterian Hospital,
Ghana
• Erasmus Klutse, Dunkwa Government Hospital, Ghana
• Kimball Crofts, Humanitarian Aid Relief Organisation,
Provo, Utah, USA, Goaso Hospital, Ghana
• François Ngos, District de Santé d’Akonolinga,
Hôpital d’Akonolinga, Cameroon
• Jörg Nitschke, Patrick Biasson, Elisabeth Le Saout,
Médecines Sans Frontieres (MSF) Swiss and
Cameroon
Investigators
• Gisela Bretzel
• Paul Racz
• Vera Siegmund
• Felicitas van Vloten
• Christian Drosten
• Kwame Opare-Asamoah
• Ruth Thompson