Leishmania donovani In Southwest of Sudan: Rapid assessment and Application of Geographic Information System
Leishmania donovani In Southwest of Sudan: Rapid assessment and Application of Geographic Information System
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Date
2006
Authors
M. El Magzoub, Ranyab
Hassan, Abdalla
Journal Title
Journal ISSN
Volume Title
Publisher
University of Khartoum
Abstract
Visceral leishmaniasis (VL) comprises a major health problem in several parts of the
Sudan and it leads to severe morbidity and high mortality if uncontrolled. Western Upper
Nile State and Southern Kordofan State were a scene of a huge outbreak that claimed
hundreds of thousands of lives in the late eighties, which demonstrated the inability, and
inadequacy of the health authorities, at that time, in dealing with such disasters that are
more likely to occur from time to time.
Control of VL is obstructing by the elusive nature of the vector and failure to identify a
reservoir host. Case detection and treatment with antimonial drugs contribute to disease
control. In this study we introduced the concept of rapid epidemiological assessment of
patterns of L. donovani infection and visualized the data in a geographic information
system (GIS) hoping to open new avenues into the question of VL control. Coupling this
map with the map of vector distribution and climatic changes will provide valuable
information that will help in disease control, despite our meagre health resources.
This survey was based on simple in vivo and in vitro immunological techniques
(leishmanin skin reactivity and the Direct Agglutination Tests), combined with clinical
history to obtain data about the spectrum of L donovani infection in communities at risk of
developing VL. The data was represented in map format to give an enhanced visual
impact. Treatment and future control strategies can easily be formulated from such data.
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In this study clinical history and immunological tests were conducted on 1781 volunteers
randomly selected from the mesairiya tribe who areliving in western Kordofan State. The
mean age of the selected volunteers was 20.7 years with an equal male:female ratio.
The overall leishmanin skin reactivity of ≥5 was 24.5%, where children below 15 years
had higher (13.2%) leishmanin reactivity compared to 11.3% among adults above that
age.
The DAT results showed that 88% (1567/1781) of the study volunteers had DAT titres below
the cut-off point of 3200, whereas 6% (112/1781) had a DAT titers = 3200, while the rest
5.7% (238/1781) had titres > 6400. DAT results were shown in Table (3.5) and Figure (3.7).
Six L donvani and one L. major strains were in vitro tested in their amastigote forms against
Pentostam and Amphotericin B using J774 murine macrophage-like cell line. The number
of parasite in the infected cells decreased steadily at drug concentration 7.8μg/ml to
250μg/ml for Pentostam and 0.22μg/ml to 0.75μg/ml for Amphotericin B and the capacity of
parasites to replicate inside the cells was also affected. In this system the parasite survival
index (PSI) was similar for both tested drugs. L major showed the same response as other
tested strains. Geographic information system (GIS) was applied in this study and the
ArcGIS software was used to draw a map of the Sudan with different layers and themes.
The maps included all the obtained information with coordinates of the studied area.
In conclusion: the use of clinical interview combined with simple immunological tests can
give valuable information about the pattern of L. donovani infection and predict future
prevalence of VL in a short time. Leishmanin non-reactive individuals are a useful piece of
data to plan for future vaccine efficacy studies. It is also clear that in vivo drug
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unresponsiveness does not correlate well with in vitro sensitivity for the same drugs. The
interactive dynamic map that was produced in the ArcGIS can act as a nucleus for
development of a Leishmania network in Sudan and the nearby countries that have the
same belt of visceral leishmaniasis.
Description
Keywords
Visceral leishmanisis in Sudan,Leishmanin skin test (LST),Direct Agglutination Test (DAT),Enzyme-linked immunosorbent assay (ELISA),Geographical Information System(GIS)