مجال
التميز
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تميز دراسي وبحثي
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البحوث المنشورة
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البحث (1):
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عنوان البحث:
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A
centenary of Robert T. Leiper’s lasting legacy on schistosomiasis and a
COUNTDOWN on control of neglected tropical diseases
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تاريخ النشر:
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01 July
2016
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موجز عن البحث:
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Part
of Robert T. Leiper’s (1881–1969) lasting legacy in medical helminthology is
grounded on his pioneering work on schistosomiasis (Bilharzia). Having
undertaken many expeditions to the tropics, his fascination with parasite
life cycles typically allowed him to devise simple preventive measures that
curtailed transmission. Building on his formative work with others in Africa
and Asia, and again in Egypt in 1915, he elucidated the life cycles of
African schistosomes. His mandate, then commissioned by the British War
Office, was to prevent and break transmission of this disease in British
troops. This he did by raising standing orders based on simple water hygiene
measures. Whilst feasible in military camp settings, today their routine
implementation is sadly out of reach for millions of Africans living in
poverty. Whilst we celebrate the centenary of Leiper’s research we draw
attention to some of his lesser known colleagues, then focus on
schistosomiasis in Uganda discussing why expanded access to treatment with
praziquantel is needed now. Looking to WHO 2020 targets for neglected
tropical diseases, we introduce COUNTDOWN, an implementation research
consortium funded by DFID, UK, which fosters the scale-up of interventions
and confirm the current relevance of Leiper’s original research.
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البحث (2):
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عنوان البحث:
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An extensive burden of giardiasis associated with
intestinal schistosomiasis and anaemia in school children on the shoreline of
Lake Albert, Uganda
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تاريخ النشر:
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09 December
2016
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موجز عن البحث:
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Background: Water-borne parasitic diseases
associated with poverty still blight the lives of African school children. In
Uganda, intestinal schistosomiasis is still common along the shoreline of
Lake Albert, despite ongoing control, and co-infection with giardiasis and
malaria is poorly described. To shed light on putative interactions between
diseases, a prospective cross-sectional parasitological survey was undertaken
in five primary schools.
Methods: Stool samples from 254 school children,
aged 5–10 years, were examined by microscopy and rapid diagnostic tests
(RDTs), with additional real-time PCR assays for detection of Giardia DNA. A
finger-prick blood sample was also taken from each child and tested for
malaria, and haemoblobin levels measured. Assocations between diseases and
anaemia were assessed.
Results: Intestinal schistosomiasis (46.5%),
giardiasis (41.6%) and malaria (56.2%) were common, and a quarter of children
were anaemic (<115 g/L). Up to 87.0% of children were excreting Giardia
DNA and the prevalence of heavy infection by real-time PCR (Ct≤19) was 19.5%, being positively associated with
light, moderate and heavy egg-patent schistosomiasis, as well as with
anaemia.
Conclusions: In this setting, an extensive burden of
giardiasis was revealed with heavy intensity infections associated with
egg-patent intestinal schistosomiasis and anaemia. To improve child health,
greater attention on giardiasis is needed along with exploring joined-up
actions across diseases that promote better water hygiene and sanitation
measures.
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البحث (3):
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عنوان البحث:
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Surveillance of intestinal schistosomiasis during
control: a comparison of four diagnostic tests across five Ugandan primary
schools in the Lake Albert region
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تاريخ النشر:
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21 March
2018
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موجز عن البحث:
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Programmatic surveillance of intestinal
schistosomiasis during control can typically use four diagnostic tests,
either singularly or in combination, but these have yet to be cross-compared
directly. Our study assembled a complete diagnostic dataset, inclusive of
infection intensities, from 258 children from five Ugandan primary schools.
The schools were purposely selected as typical of the endemic landscape near
Lake Albert and reflective of high- and low-transmission settings. Overall
prevalence was: 44.1% (95% CI 38.0–50.2) by microscopy of duplicate Kato-Katz
smears from two consecutive stools, 56.9% (95% CI 50.8–63.0) by
urine-circulating cathodic antigen (CCA) dipstick, 67.4% (95% CI 61.6–73.1)
by DNA-TaqMan® and 75.1% (95% CI 69.8–80.4) by soluble egg antigen
enzyme-linked immunosorbent assay (SEA-ELISA). A cross-comparison of
diagnostic sensitivities, specificities, positive and negative predictive
values was undertaken, inclusive of a latent class analysis (LCA) with a
LCA-model estimate of prevalence by each school. The latter ranged from 9.6%
to 100.0%, and prevalence by school for each diagnostic test followed a
static ascending order or monotonic series of Kato-Katz, urine-CCA dipstick,
DNA-TaqMan® and SEA-ELISA. We confirm that Kato-Katz remains a satisfactory
diagnostic standalone in high-transmission settings but in low-transmission
settings should be augmented or replaced by urine-CCA dipsticks. DNA-TaqMan®
appears suitable in both endemic settings though is only implementable if
resources permit. In low-transmission settings, SEA-ELISA remains the method
of choice to evidence an absence infection. We discuss the pros and cons of
each method concluding that future surveillance of intestinal schistosomiasis
would benefit from a flexible, context-specific approach both in choice and
application of each diagnostic method, rather than a single one-size fits all
approach.
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البحث (4):
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عنوان البحث:
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Molecular detection of equine trypanosomiasis in the
Riyadh Province of Saudi Arabia
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تاريخ النشر:
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11 September 2018
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موجز عن البحث:
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We conducted a cross-sectional study to detect
trypanosome infections of horses and donkeys in the Riyadh Province of Saudi
Arabia. DNA was extracted from blood samples collected from 368 horses and
142 donkeys, and subjected to universal first ribosomal internal transcribed
spacer region (ITS1)-PCR followed by Trypanosoma evansi species–specific
RoTat1.2-PCR. The universal ITS1-PCR revealed T. evansi infection in horses
(n = 12; 3.3%) and donkeys (n = 4; 2.8%). There was no significant effect of
sex or age on the prevalence of trypanosomiasis in horses or donkeys.
Application of the RoTat1.2-PCR revealed that the RoTat1.2 VSG gene was
absent from the positive ITS1-PCR samples of 3 horses and 1 donkey. This
discrepancy could be explained by the circulation of T. evansi type B in
Saudi Arabia; however, this suspicion requires confirmation.
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المؤتمرات العلمية:
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المؤتمر (1):
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عنوان المؤتمر:
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American
Society of Tropical Medicine and Hygiene (ASTMH) 66th Annual Meeting
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تاريخ الإنعقاد:
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5-9 November
2017
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مكان
الإنعقاد:
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Baltimore, Maryland, USA
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طبيعة المشاركة:
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Poster Presentation
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عنوان المشاركة:
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An
Evolution of Parasitological- and Serological-Based Methods for Diagnosis
ofIntestinal Schistosomiasis in High-Low Endemic Settings
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ملخص المشاركة:
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Infection
with intestinal schistosomiasis is typically common in children, particularly
within regions of sub-Saharan Africa where environmental water contact is
high and access to adequate sanitation is poor. Traditional parasitological
methods of diagnosis that visualise parasite ova underestimate true prevalence
and as control programmes progress, infection egg-tallies may also decline.
Consequently, there is a need to develop better methods for detection of
schistosomiasis, especially in countries such as Uganda where ongoing
school-based control has taken place for over a decade. Against this country-backdrop,
we investigate the application of novel diagnostics to shed light on current
levels of infection across 5 primary schools within Buliisa District, Lake
Albert. We evaluated parasitological- and serological-based methods alongside
real-time PCR and focused upon examination of children of school-age (i.e.
5-10 years). PCR-based methods explored the use of Taqman® assays on faecal samples.
We assessed the diagnostic congruence between methods and report that
intestinal schistosomiasis is still pervasive within this lakeshore
environment.
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