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"Debrah, Alexander"
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Wuchereria bancrofti-infected individuals harbor distinct IL-10-producing regulatory B and T cell subsets which are affected by anti-filarial treatment
2019
Despite worldwide mass drug administration, it is estimated that 68 million individuals are still infected with lymphatic filariasis with 19 million hydrocele and 17 million lymphedema reported cases. Despite the staggering number of pathology cases, the majority of LF-infected individuals do not develop clinical symptoms and present a tightly regulated immune system characterized by higher frequencies of regulatory T cells (Treg), suppressed proliferation and Th2 cytokine responses accompanied with increased secretion of IL-10, TGF-β and infection-specific IgG4. Nevertheless, the filarial-induced modulation of the host`s immune system and especially the role of regulatory immune cells like regulatory B (Breg) and Treg during an ongoing LF infection remains unknown. Thus, we analysed Breg and Treg frequencies in peripheral blood from Ghanaian uninfected endemic normals (EN), lymphedema (LE), asymptomatic patent (CFA+MF+) and latent (CFA+MF-) W. bancrofti-infected individuals as well as individuals who were previously infected with W. bancrofti (PI) but had cleared the infection due to the administration of ivermectin (IVM) and albendazole (ALB). In summary, we observed that IL-10-producing CD19+CD24highCD38dhigh Breg were specifically increased in patently infected (CFA+MF+) individuals. In addition, CD19+CD24highCD5+CD1dhigh and CD19+CD5+CD1dhighIL-10+ Breg as well as CD4+CD127-FOXP3+ Treg frequencies were significantly increased in both W. bancrofti-infected cohorts (CFA+MF+ and CFA+MF-). Interestingly, the PI cohort presented frequency levels of all studied regulatory immune cell populations comparable with the EN group. In conclusion, the results from this study show that an ongoing W. bancrofti infection induces distinct Breg and Treg populations in peripheral blood from Ghanaian volunteers. Those regulatory immune cell populations might contribute to the regulated state of the host immune system and are probably important for the survival and fertility (microfilaria release) of the helminth.
Journal Article
Changes in circulating filarial antigen status in previously positive individuals: Lessons for treatment monitoring and pre-transmission assessment surveys
2025
The Global Programme to Eliminate Lymphatic Filariasis has made significant gains through mass drug administration (MDA) of Ivermectin/Albendazole. Periodic evaluation of the MDA programme in lymphatic filariasis elimination is particularly useful in determining end points for stopping the programme. This is a follow-up study that sought to examine the effects of additional time and MDA intake on antigenemia seroreversion in persons who had previously tested positive for LF using the Filarial Test Strip (FTS) and the TropBio ELISA over a period of 1-5 years.
A total of 542 individuals, from the Kassena Nankana East Municipal (N = 340) and Nabdam districts (N = 202) in the Upper East Region of Ghana, who had previously tested either positive (N = 446) or negative (N = 96) for FTS-CFA, participated in the study. Two follow-up visits were conducted; 1-4 years (follow-up-1) and 2-5 years (follow-up-2) after the baseline visit. Of the 446 FTS-CFA positives, 175 (39.2%) did not receive additional MDA (ivermectin/Albendazole) after the baseline visit. Overall, from the two follow-up visits, 159/175 (90.9%) FTS-CFA+ participants who did not receive any additional Ivermectin/Albendazole and 226 out of the 271 (83.4%) with additional MDA treatment became CFA negative. A total of 120 randomly selected baseline FTS-CFA+ samples were tested with Og4C3 TropBio ELISA and only 44/120 (36.7%) were found positive. Of these 44 participants, 12 (27.3%) completely became CFA negative and an additional 18 (40.9%) had reduced antigen levels during the follow-up. Likewise, all three previously/baseline microfilariae positive persons had become amicrofilaremic.
In the present work, it has been shown that >90% of the previous CFA positive individuals seroreverted in 1 to 5 years post-baseline without additional MDA. The FTS is a more sensitive diagnostic tool that plausibly detects residual CFA in blood. The impact and influence of time as compared to additional ivermectin/Albendazole intake, on CFA seroreversion in this study was significant (p < 0.001).
Journal Article
Morbidity management and surveillance of lymphatic filariasis disease and acute dermatolymphangioadenitis attacks using a mobile phone-based tool by community health volunteers in Ghana
2020
Morbidity burden of lymphatic filariasis (LF) relies on the information from the Mass Drug Administration (MDA) programme where Community Health Volunteers (CHVs) passively report cases identified. Consequently, the exact prevalence of morbidity cases is not always accurate. The use of mobile phone technology to report morbidity cases was piloted in Ghana using a text-based short messaging service (SMS) tool by CHVs. Though successful, illiterate CHVs could not effectively use the SMS tool. The aim of this study was to evaluate the use of a mobile phone-based Interactive Voice Response System (mIVRS) by CHVs in reporting LF morbidity cases and acute dermatolymphangioadenitis (ADLA) attacks in Ghana. The mIVRS was designed as a surveillance tool to capture LF data in Kassena Nankana Districts of Ghana. One hundred CHVs were trained to identify and report lymphedema and hydrocele cases as well as ADLA attacks by calling a hotline linked to the mIVRS. The system asked a series of questions about the disease condition. The ability of the CHV to report accurately was assessed and the data from the mIVRS were compared with the paper records from the CHVs and existing MDA programme records from the same communities and period. Higher numbers of lymphedema and hydrocele cases were recorded by the CHVs using the mIVRS (n = 590 and n = 103) compared to the paper-based reporting (n = 417 and n = 76) and the MDA records (n = 154 and n = 84). Female CHVs, CHVs above 40 years, and CHVs with higher educational levels were better at paper-based reporting ( P = 0.007, P = 0.001, P = 0.049 respectively). The system, when fully developed and linked to national databases, may help to overcome underreporting of morbidity cases and ADLA attacks in endemic communities. The system has the potential to be further expanded to other diseases.
Journal Article
Reference intervals for selected haematological and biochemical parameters among apparently healthy adults in different eco-geographical zones in Ghana
by
Gyasi, Charles
,
Afrifah, David Amoah
,
Adu-Gyamfi, Constance
in
Abuse
,
Biochemistry
,
Biology and Life Sciences
2021
Due to the influence of gender, race/genetics, age, lifestyle habits and geography on the references intervals (RIs), the Clinical and Laboratory Standards Institute (CLSI) recommends the determination of population-specific RIs. Ghana continues to depend on pre-established RIs from other countries which poses the risk of misdiagnoses and wrong treatment. This study presents the haemato-biochemical RIs from four eco-geographical zones in Ghana.
In this population-based cross-sectional study, a total of 1227 randomly selected healthy voluntary blood donors from the four eco-geographic zones (Coastal Savannah, Rain Forest, Savannah and Transitional) were enrolled and screened. Based on the CLSI Guidance Document C28A2992, the data of eligible participants were used to non-parametrically determine the RIs for the haemato-biochemical parameters at the 2.5th and 97.5th percentiles. Comparison of analytes by gender was done by Wilcoxon rank sum test and eco-geographic differences were assessed using the Kruskal-Wallis with the Dunn post hoc multiple comparison tests.
There were statistically significant differences in most of the haematological parameters (RBC, Hb, HCT, MCV, PLT, WBC; p-values <0.0001 and MCH; p-value = 0.007), and biochemical analytes (Urea, Cr, Trig, HDL-C, AST, ALT, ALP, GGT, BID, BIT, Prot-T and Albumin; p-values <0.0001) based on gender. Significant inter eco-geographic (intra-population) variations and substantial differences between the established RI and the RIs accompanying the analyzers used were also observed.
This study reports significant inter-sex and inter-geographical differences in haemato-biochemical RIs in Ghana as well as differences in RIs with both the RIs accompanying the analyzers and those of other countries. Determining RIs representative of populations and including them in the report systems of laboratories to ensure effective and efficient healthcare service delivery is thus recommended.
Journal Article
Plasminogen Activator Inhibitor-1 in poorly controlled vs well controlled Type-2 Diabetes Mellitus patients: A case-control study in a district hospital in Ghana
by
Derigubah, Charles A.
,
Mensah, Kofi
,
Owusu, Michael
in
Antigens
,
Biology and life sciences
,
Blood donors
2021
Hypofibrinolysis resulting from the up-regulation of plasminogen activator inhibitor-1 (PAI-1) usually occurs in patients with type 2 diabetes mellitus (T2DM), rendering them hypercoagulable. This study assessed the plasma antigen and activity levels of the PAI-1 enzyme in T2DM patients in a district hospital in Ghana.
This was a hospital-based case-control study conducted from December 2018 to May 2019 at Nkenkaasu District Hospital. Sixty subjects with T2DM (30 T2DM subjects with good glycemic control and 30 with poor glycemic control), and 30 apparently healthy blood donors were recruited into the study. Blood specimens were collected for complete blood count, lipid profile, PAI-1 Ag and PAI-1 activity levels. A pre-tested questionnaire was used to obtain demographic and clinical information. The data was analyzed using SPSS version 22.0.
Elevated PAI-1 Ag and activity levels were observed in the T2DM subjects compared to the healthy controls, with the levels and activity significantly higher (PAI-1 Ag; p< 0.001, PAI-1 activity level; p = 0.004) in the T2DM subjects with poor glycemic control in comparison to those with good glycemic control. A significant positive correlation was observed between HbA1c and PAI-1 enzymes. PAI-1 Ag levels significantly increased along with increased total cholesterol (Β = 0.262, p = 0.033), triglyceride (Β = -0.273, p = 0.034) and HbA1c (Β = 0.419, p = 0.001). Similarly, PAI-1 activity level was associated with total cholesterol (Β = 0.325, p = 0.009), triglyceride (Β = -0.262, p = 0.042), HbA1c (Β = 0.389, p = 0.003) and VLDL-c (Β = -0.227, p = 0.029).
PAI-1 antigen/activity is enhanced in poorly controlled Ghanaian T2DM subjects. The hypercoagulable state of the affected individuals put them at higher risk of developing cardiovascular diseases. Good glycemic control to regulate plasma PAI-1 levels is essential during T2DM lifelong management. Markers of fibrinolysis should be assessed in these individuals and appropriate anticoagulants given to prevent thrombosis and adverse cardiovascular diseases.
Journal Article
Diversity of Culicoides in the middle belt of Ghana with Implications on the transmission of Mansonella perstans; a molecular approach
2024
Background
Culicoides
, also known as biting midges, carry pathogens which include
Mansonella perstans
.
Mansonella perstans
is a nematode parasite implicated in a number of disease outcomes. Even though a high prevalence of about 75%
M. perstans
infection has been recorded in some communities in the middle belt of Ghana, and a wide diversity of
Culicoides
species has been identified, the exact
Culicoides
species transmitting
M. perstans
in Ghana has not yet been deciphered. This study therefore aimed at assessing the species diversity of
Culicoides
and their role in the transmission of
M. perstans
in the middle belt of Ghana.
Methods
Culicoides
species were sampled from 11 communities in the Asante-Akim North and Sene West districts in the middle belt of Ghana. Centre for Disease Control (CDC) UV light traps, as well as human bait (i.e. human landing catch and engorged catch) methods were used to assess the species abundance and diversity of
Culicoides
in the study communities in the wet and dry season. A colorimetric Loop-Mediated Isothermal Amplification (LAMP) assay was performed to assess the vector competence of the various
Culicoides
species.
Results
A total of 4810
Culicoides
from 6 species were sampled. These included
Culicoides inornatipennis, C. milnei, C. schultzei, C. grahamii, C. neavei
, and
C. imicola. Culicoides imicola
was the most abundant species (56%) followed by
C. grahamii
(16%). Light traps sampled the most diverse species (6 species). Human landing catch and engorged catch methods identified three anthropophilic species,
C. grahamii, C. milnei
, and
C. inornatipennis
, with
C. grahamii
being the most anthropophilic with a peak biting time between the hours of 5 p.m. to 6 p.m. Generally, there was relatively higher species abundance in the wet than dry season. LAMP assay identified
C. grahamii
as the potential vector for
M. perstans
transmission in the middle belt of Ghana.
Conclusions
For the first time, we have demonstrated that
C. grahamii
is the potential competent vector for
M. perstans
transmission in the middle belt of Ghana. It is more abundant in the rainy season and has a peak biting time between the hours of 5 and 6 p.m.
Graphical Abstract
Journal Article
Vector-borne helminthiases: a road map for current and future research to support control and elimination in sub-Saharan Africa
by
Basáñez, María-Gloria
,
Coulibaly, Yaya
,
Kamgno, Joseph
in
Antiparasitic agents
,
Best practice
,
Capacity development
2025
Disease-specific and data initiatives Over the past five decades, several global disease-specific programmes, declarations, development initiatives, and strategic road maps have been initiated to address these diseases in response to varying levels of risk, stakeholders' commitments, and funding opportunities. 1 A needs assessment in all countries endemic for onchocerciasis published in 2023 identified key areas to address, such as cross-border collaboration, advocacy for domestic funding, sharing of best practices for implementation, access to diagnostics and laboratories, capacity building, and community support. 10 Lymphatic filariasis Lymphatic filariasis is caused by three species of filarial parasites, namely, Wuchereria bancrofti, Brugia malayi, and B timori, and is endemic in 72 countries in the world, including 35 countries in the WHO African region (where only W bancrofti is present). In the WHO road map for 2021–30, lymphatic filariasis is targeted for validation of elimination as a public health problem in 58 countries in which the infection is endemic by 2030, with stop-MDA targets for the remaining countries. 1 Currently, African lymphatic filariasis programmes are supported by ESPEN. 9 Loiasis Loiasis, also known as African eye worm, is caused by the filarial parasite Loa loa and transmitted to humans by tabanid Chrysops spp flies. 4,13 Loiasis is present in the equatorial forest regions of central and west Africa and is endemic in ten countries. Because the infection has been largely thought to be subclinical, or to have only mild symptoms (eg, non-tender limb, joint, and occasional orbital swellings, and so-called eye worm movements crossing beneath the conjunctiva), loiasis has not been prioritised as a public health concern. The distribution of loiasis based on eye worm history was mapped between 2002 and 2010 to better inform onchocerciasis and lymphatic filariasis programmes in areas at risk for serious adverse events (SAEs; including fatal encephalopathy) associated with the distribution of ivermectin to people with high L loa microfilarial densities. 4,14,15 For this reason, loiasis is considered a disease of interest by WHO's ESPEN. 9 Mansonellosis In Africa, mansonellosis is caused by two filarial parasites of the genus Mansonella (formerly Dipetalonema), namely , M perstans and M streptocerca, and is transmitted by Culicoides midges . 5–7 Mansonellosis is widespread in many sub-Saharan African regions, infecting millions of people.
Journal Article
Filarial Lymphedema Patients Are Characterized by Exhausted CD4+ T Cells
by
Wiszniewsky, Anna
,
Osei-Mensah, Jubin
,
Chachage, Mkunde
in
Antigens
,
CD4 antigen
,
CD4+ T cell exhaustion
2022
Worldwide, more than 200 million people are infected with filariae which can cause severe symptoms leading to reduced quality of life and contribute to disability-adjusted life years (DALYs). In particular, lymphatic filariasis (LF) caused by Wuchereria bancrofti can lead to lymphedema (LE) and consequently presents a serious health problem. To understand why only a fraction of the infected individuals develop pathology, it is essential to understand how filariae regulate host immunity. The central role of T cells for immunity against filariae has been shown in several studies. However, there is little knowledge about T cell exhaustion, which causes T cell dysfunction and impaired immune responses, in this group of individuals. Recently, we showed that LE patients from Ghana harbor distinct patterns of exhausted effector and memory CD8 + T cell subsets. Based on these findings, we now characterized CD4 + T cell subsets from the same Ghanaian patient cohort by analyzing distinct markers within a 13-colour flow cytometry panel. We revealed that LE patients had increased frequencies of CD4 + T cells expressing exhaustion-associated receptors such as KLRG-1, TIM-3 and PD-1 compared to healthy endemic normal and W. bancrofti -infected individuals. Moreover, CD4 + T cells in LE patients were characterized by distinct co-expression patterns of inhibitory receptors. Collectively with the previous findings on CD8 + T cell exhaustion patterns, the data shown here demonstrates that filarial LE patients harbor distinct subsets of exhausted T cells. Thus, T cell exhaustion patterns in LE patients need attention especially in regards to susceptibility of concomitant infections and should be taken into consideration for LE management measures.
Journal Article
Distinct Immune Profiles of Exhausted Effector and Memory CD8+ T Cells in Individuals With Filarial Lymphedema
by
Wiszniewsky, Anna
,
Osei-Mensah, Jubin
,
Chachage, Mkunde
in
Antibodies
,
Antigens
,
Asymptomatic
2021
CD8 + T cells are crucial for the clearance of viral infections, and current research begins to highlight their importance in parasitic diseases too. In-depth research about characteristics of CD8 + T-cell subsets and exhaustion remains uncertain, especially during filariasis, a chronic helminth infection. Lymphatic filariasis, elicited by Wuchereria bancrofti , remains a serious health problem in endemic areas in Ghana, especially in those suffering from morbidity due to lymphedema (LE). In this observational study, the characteristics and profiles of CD8 + T cells were compared between asymptomatic Wuchereria bancrofti -infected individuals, uninfected endemic normals, and those with LE (grades 2–6). Focusing on exhausted memory (CD8 + ex mem : CD8 + T-bet dim Eomes hi ) and effector (CD8 + ex eff : CD8 + T-bet hi Eomes dim ) CD8 + T-cell subsets, advanced flow cytometry revealed that LE individuals presented reduced frequencies of IFN-γ + CD8 + ex mem T cells expressing Tim-3 or LAG-3 which negatively correlated to the presence of LE. Moreover, the LE cohort further showed significantly higher frequencies of IL-10 + CD8 + ex eff T cells expressing either Tim-3, LAG-3, CD39, KLRG-1, or PD-1, all associated markers of exhaustion, and that these frequencies positively correlated with the presence of LE. In summary, this study shows that distinct exhausted CD8 + T-cell subsets are prominent in individuals suffering from LE, suggesting that enhanced inflammation and constant immune activation might drive exhaustion of CD8 + T cells. Since T-cell exhaustion is known to be associated with insufficient control of persisting antigen, the data presented here reveals that these CD8 + T-cell exhaustion patterns in filarial LE should be taken into consideration for prevention and control management of LE.
Journal Article
Comparison of Doxycycline, Minocycline, Doxycycline plus Albendazole and Albendazole Alone in Their Efficacy against Onchocerciasis in a Randomized, Open-Label, Pilot Trial
2017
The search for new macrofilaricidal drugs against onchocerciasis that can be administered in shorter regimens than required for doxycycline (DOX, 200mg/d given for 4-6 weeks), identified minocycline (MIN) with superior efficacy to DOX. Further reduction in the treatment regimen may be achieved with co-administration with standard anti-filarial drugs. Therefore a randomized, open-label, pilot trial was carried out in an area in Ghana endemic for onchocerciasis, comprising 5 different regimens: the standard regimen DOX 200mg/d for 4 weeks (DOX 4w, N = 33), the experimental regimens MIN 200mg/d for 3 weeks (MIN 3w; N = 30), DOX 200mg/d for 3 weeks plus albendazole (ALB) 800mg/d for 3 days (DOX 3w + ALB 3d, N = 32), DOX 200mg/d for 3 weeks (DOX 3w, N = 31) and ALB 800mg for 3 days (ALB 3d, N = 30). Out of 158 randomized participants, 116 (74.4%) were present for the follow-up at 6 months of whom 99 participants (63.5%) followed the treatment per protocol and underwent surgery. Histological analysis of the adult worms in the extirpated nodules revealed absence of Wolbachia in 98.8% (DOX 4w), 81.4% (DOX 3w + ALB 3d), 72.7% (MIN 3w), 64.1% (DOX 3w) and 35.2% (ALB 3d) of the female worms. All 4 treatment regimens showed superiority to ALB 3d (p < 0.001, p < 0.001, p = 0.002, p = 0.008, respectively), which was confirmed by real-time PCR. Additionally, DOX 4w showed superiority to all other treatment arms. Furthermore DOX 4w and DOX 3w + ALB 3d showed a higher amount of female worms with degenerated embryogenesis compared to ALB 3d (p = 0.028, p = 0.042, respectively). These results confirm earlier studies that DOX 4w is sufficient for Wolbachia depletion and the desired parasitological effects. The data further suggest that there is an additive effect of ALB (3 days) on top of that of DOX alone, and that MIN shows a trend for stronger potency than DOX. These latter two results are preliminary and need confirmation in a fully randomized controlled phase 2 trial.
ClinicalTrials.gov #06010453.
Journal Article