54 research outputs found
External Quality Assessment on CD4+ T-Cell Count Using in-House Proficiency Testing Panels for CD4 Count Laboratories in Addis Ababa, Ethiopia
BACKGROUND: CD4+ T-cell count External Quality Assessment program is important for the evaluation of performance of CD4 count laboratories. The aim of this study was to assess the quality of CD4count laboratory performance using in-house Proficiency testing panels that perform routineCD4 counts in Addis Ababa, Ethiopia, 2013/14.METHODS: Participating laboratories were 20, 23 and 25 in trials 1, 2 and 3, respectively. In-house prepared fresh whole blood samples both with ānormalā and ālowā CD4 values were sent to participating laboratories. Percentage and absolute counts of CD4+ T-lymphocytes were done using their routine procedures. Data were analyzed for each trial including trimmed mean, standard deviation (SD), percent coefficient of variation (%CV), residual, and standard deviation index (SDI) values for both absolute counts and percentages of CD4+ lymphocytes (%CD4).RESULTS: Most participating laboratories produced results that were within 2SD of the mean. Average inter-laboratory precision (trimmed %CV) was 10.87% and 5.14% for CD4 absolute counts and %CD4, respectively. For normal material, the trimmed mean %CV was 9.59% and3.23% for CD4 absolute counts and %CD4, respectively. For low material, the trimmed mean % CV was 12.15% and 7.05% for CD4 absolute counts and %CD4 respectively. BDFACSCountā¢ users showed the best accuracy and precision as evidenced by longitudinal analysis.CONCLUSION: This study was found to help facilities in early identifying their gaps with regard to their CD4 count performance and in avoiding the challenges encountered during participation in external EQA providers like the high cost, transportation problem, feedback delay and CD4laboratory coverage.
Parasito-haematological features of acute Plasmodium falciparum and P. vivax malaria patients with and without HIV co-infection at Wonji Sugar Estate, Ethiopia
No Abstract.Ethiopian Journal of Health Development Vol. 19 (2) 2005: 132-13
Interrogating the Impact of Intestinal Parasite-Microbiome on Pathogenesis of COVID-19 in Sub-Saharan Africa
Intestinal parasitic infections affect more than 2 billion people throughout the world with disproportionately high prevalence rates in Low- and Middle-Income Countries (LMICs) (Herricks et al., 2017). Multicellular and highly complex parasites such as Ascaris, hook worm, Trichuris, Enterobius and Schistosoma, as well as unicellular organisms including Entamoeba, Giardia, Toxoplasma, Cyclospora, and Cryptosporidium are among major pathogens that contribute to the global intestinal parasitic disease burden.
Parasites can cause persistent infection due to their ability to resist immune-mediated expulsion by modulating the host's immune response (McSorley and Maizels, 2012; Wammes et al., 2014; ChabƩ et al., 2017; Burrows et al., 2019; Ryan et al., 2020). There is a complex interaction between parasites and human microbiota which can triangulate with host's immune homeostasis and host responses to bystander antigens, vaccines or other unrelated diseases, both infectious and non-communicable diseases (McSorley and Maizels, 2012; Wammes et al., 2014). Recently, the world has grappled with an unprecedented pandemic due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection that causes coronavirus disease 2019 (COVID-19) (WHO, 2020). The pathogenesis of severe disease in COVID-19 has been linked to the phenomenon of immune hyperactivation (Sinha et al., 2020; Tay et al., 2020). Here, we propose that the interplay between intestinal parasites and microbiome may have a potential direct or indirect effects on the pathogenesis of SARS-CoV-2 infection, in particular in the context of LMICs
African AIDS Vaccine Programme for a Coordinated and Collaborative Vaccine Development Effort on the Continent
The African AIDS Vaccine Programme, formed in 2000, is a network of African HIV vaccine stakeholders, led by Africans across the continent, with a vision of an African continent without AIDS
Low-cost liquid medium for in vitro cultivation of Leishmania parasites in low-income countries
Background: Cutaneous Leishmaniasis (CL) induced by Leishmania aethiopica
has two clinical manifestations: ulcerating, self-healing CL and
non-ulcerating, non-healing CL. The grossly disfiguring multiple nodules
on the face and exterior surface of limbs during non-ulcerative CL are
sometimes misdiagnosed as other skin infections. Thus the need for
definitive and prompt laboratory diagnosis will be required. Identifying
Leishmania parasite by culture method is considered as a definitive
method for initiation of treatment and as an effective component of
leishmaniasis control methods. Recently the involvement of Fas (CD95)
and Tumor Necrosis Factor (TNF) Related Apoptosis Inducing Ligand (TRAIL)
induced apoptotic pathways were proposed to be involved in tissue
destruction and ulceration during L. major induced CL.
Aims: 1) to develop an alternative culture media that could minimize the
cost for culturing Leishmania from patient lesions.
2) to investigate if the expression of FasL and TRAIL differs in
ulcerating and non- ulcerative CL.
Methods: GALF-1 media was formulated in our lab and compared to RPMI 1640
medium and conventional Locke s semi solid media (LSSM) which is one of
the modifications of Novy-MacNeal-Nicolle (NNN) culture media.
Amastigotes transformation, cryopreservation, recovery of parasites, cost
and mass cultivation were analysed. Expression of Fas ligand (FasL),
TRAIL and apoptosis were assessed by immunohistology in human skin
biopsies from L. aethiopica induced ulcerative or non-ulcerative CL. FasL
and TRAIL blocking experiments were performed in a murine model of CL.
Results and discussion: GALF-1 is cheap and its ingredients available in
a low income country such as Ethiopia. GALF-1 was able to transform
amastigotes from Ethiopian patients samples and could be used to
cultivate promastigotes in large quantities. Cost analysis showed 80% to
95 % decreased costs as compared to conventional media. Promastigotes
cultured with GALF-1 could be cryopreserved in liquid nitrogen with
comparable re-culture potential to conventional media. Affordability of
diagnostic assays is a key issue for resource poor countries and the
possibility to cut the cost of the efficient culture method for diagnosis
through the use of inexpensive local formulated reagents could improve
the diagnosis of leishmaniasis in low income endemic countries.
More FasL expressing cells were detected in dermis of ulcerative CL as
compared to non-ulcerative CL and controls. TRAIL expression was higher
in ulcerative CL as compared to non-ulcerative CL and controls in both
epidermis and dermis. Increased dermal expression of FasL and TRAIL was
associated with ulcer formation during CL. This correlated with an
inhibition of the ulcerative process in a murine CL model during FasL and
TRAIL neutralisation.The mechanisms of the involvement of FasL and TRAIL
in ulceration was not elucidated and putative reason(s) for the
difference in dysregulation of apoptosis are discussed
Effect of co-infection with intestinal parasites on COVID-19 severity: A prospective observational cohort study
Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection results in a spectrum of clinical presentations. Evidence from Africa indicates that significantly less COVID-19 patients suffer from serious symptoms than in the industrialized world. We and others previously postulated a partial explanation for this phenomenon, being a different, more activated immune system due to parasite infections. Here, we aimed to test this hypothesis by investigating a potential correlation of co-infection with parasites with COVID-19 severity in an endemic area in Africa.
Methods: Ethiopian COVID-19 patients were enrolled and screened for intestinal parasites, between July 2020 and March 2021. The primary outcome was the proportion of patients with severe COVID-19. Ordinal logistic regression models were used to estimate the association between parasite infection, and COVID-19 severity. Models were adjusted for sex, age, residence, education level, occupation, body mass index, and comorbidities.
Findings: 751 SARS-CoV-2 infected patients were enrolled, of whom 284 (37.8%) had intestinal parasitic infection. Only 27/255 (10.6%) severe COVID-19 patients were co-infected with intestinal parasites, while 257/496 (51.8%) non-severe COVID-19 patients were parasite positive (p<0.0001). Patients co-infected with parasites had lower odds of developing severe COVID-19, with an adjusted odds ratio (aOR) of 0.23 (95% CI 0.17ā0.30; p<0.0001) for all parasites, aOR 0.37 ([95% CI 0.26ā0.51]; p<0.0001) for protozoa, and aOR 0.26 ([95% CI 0.19ā0.35]; p<0.0001) for helminths. When stratified by species, co-infection with Entamoeba spp., Hymenolepis nana, Schistosoma mansoni, and Trichuris trichiura implied lower probability of developing severe COVID-19. There were 11 deaths (1.5%), and all were among patients without parasites (p = 0.009).
Interpretation: Parasite co-infection is associated with a reduced risk of severe COVID-19 in African patients. Parasite-driven immunomodulatory responses may mute hyper-inflammation associated with severe COVID-19.
Funding: European and Developing Countries Clinical Trials Partnership (EDCTP) ā European Union, and Joep Lange Institute (JLI), The Netherlands
Leishmania and HIV-1 interaction : immunopathogenic mechanisms
Both Leishmania and HIV can infect and multiply in macrophages, and both
can dysregulate the T-helper (Th) immune system. This thesis was,
therefore, undertaken to unravel some of the underlying immunopathogenic
mechanisms of the interaction of the two pathogens.
Clinical findings at presentation in some of our visceral leishmaniasis
(VL)-HIV co-infected patients were atypical (i.e. absence of
organomegaly) with high parasite load, severe immunosuppression (low
CD4/CD8 ratio) and frequent relapse following successful initial
response. Heat-inactivated (HI)-HIV-1 inhibited Leishmania-induced cell
proliferation, but not IL-6 and TNF-[alpha] secretion, suggesting that
the parasite can activate HIV. In addition, both HI and live HIV led to
the uncontrolled growth of Leishmania in monocytes.
Stimulation of CD8-depleted peripheral blood mononuclear cells (PBMCs)
from asymptomatic HIV-1 infected persons with Leishmania or
lipophosphoglycan (LPG), a major membrane constituent of Leishmania,
resulted in HIV-1 replication, cellular immune activation CD4+T cell
apoptosis. Interestingly, the immunomodulatory compound thalidomide
inhibited Leishmania antigen-induced secretion of TNF-[alpha] and virus
replication, with no effect on IL-2 or IL-6 production, cellular
activation and apoptosis. They suggest that TNF-[alpha] secretion is
pivotal in the process of induction of HIV replication. Thalidomide may
be of potential use to reduce HIV disease progression in VL co-infected
patients. The in vitro findings were supported by the observations we
made in vivo; persistence of parasite and hence active VL in patients who
failed antileishmanial chemotherapy was associated with high HIV load
than in those who had good response to therapy. Moreover, proliferative
responses to PHA or Leishmania were lower in VL and/or HIV-infected
persons compared to healthy controls. PBMC from healthy donors produced
high levels of Th1 cytokine (IFN-[gamma]), Th1-inducing cyokines (IL-12 &
IL-18), and low Th2 cytokines (IL-4 & IL-10); HI-HIV abrogated the
production of IFN-[gamma] induced by Leishmania and augmented IL-4 and
IL- 10. In contrast, VL and/or HIV-infected produced low levels of Th I
or Th I -inducing cyokines, but high levels of IL-10. data suggest that
the inhibitory effect of HIV and VL on the proliferative and IFN-[gamma]
production was not only due to IL- 10, but also that the defect induced
by HIV and VL probably operate at the level of regulation of
IFN-[gamma]-inducing factors
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