Publications by authors named "Yabo J Honkpehedji"

Background: SARS-CoV-2 has been associated with a higher proportion of asymptomatic infections and lower mortality in sub-Saharan Africa than high-income countries. However, there is currently a lack of data on cellular immune responses to SARS-CoV-2 in people living in Africa compared with people in high-income regions of the world. We aimed to assess geographical variation in peripheral and mucosal immune responses.

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Objectives: Despite evidence of praziquantel's (PZQ) safety for treating schistosomiasis in pregnancy, many countries withhold treatment. Only two randomized controlled trials have investigated PZQ in pregnancy, none involving Schistosoma haematobium.

Methods: Pregnant women during the second trimester in Lambaréné (Gabon) were screened for S.

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Background: Infection with the filarial nematode Loa loa, endemic in Central and Western Africa, has been associated with increased morbidity and mortality. A number of reports described the presence of spleen nodules, originating from degenerating microfilariae, in humans and animals infected with L. loa.

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Poor birth outcomes in low- and middle income countries are associated with maternal vitamin D deficiency and chronic helminth infections. Here, we investigated whether maternal Schistosoma haematobium affects maternal or cord vitamin D status as well as birth outcomes. In a prospective cross-sectional study of pregnant women conducted in Lambaréné, Gabon, we diagnosed maternal parasitic infections in blood, urine and stool.

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Background: Despite dengue virus (DENV) outbreak in Gabon a decade ago, less is known on the potential circulation of DENV serotypes in the country. Previous studies conducted in some areas of the country, are limited to hospital-based surveys which reported the presence of some cases of serotype 2 and 3 seven years ago and more recently the serotype 1. As further investigation, we extend the survey to the community of Moyen Ogooué region with the aim to assess the presence of the dengue virus serotypes, additionally to characterize chikungunya (CHIKV) infection and describe the symptomatology associated with infections.

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Background: A human hookworm vaccine is being developed to protect children against iron deficiency and anaemia associated with chronic infection with hookworms. Necator americanus aspartic protease-1 (Na-APR-1) and N americanus glutathione S-transferase-1 (Na-GST-1) are components of the blood digestion pathway critical to hookworm survival in the host. Recombinant Na-GST-1 and catalytically inactive Na-APR-1 (Na-APR-1[M74]) adsorbed to Alhydrogel were safe and immunogenic when delivered separately or co-administered to adults in phase 1 trials in non-endemic and endemic areas.

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Introduction: Schistosomiasis is a significant public health concern, especially in Sub-Saharan Africa. Conventional microscopy is the standard diagnostic method in resource-limited settings, but with limitations, such as the need for expert microscopists. An automated digital microscope with artificial intelligence (Schistoscope), offers a potential solution.

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Article Synopsis
  • Soil-transmitted helminth (STH) infections pose a significant public health issue in certain regions, prompting the need for careful monitoring of their epidemiology, including prevalence, incidence, and post-treatment reinfection rates in Gabon.
  • A study involving 262 participants aged 6 to 30 was conducted over follow-up periods of six and nine months, utilizing stool sample analysis to measure STH infection rates and identify risk factors.
  • Findings revealed a moderate prevalence of STH infections at 42% and 44% across the follow-up periods, with Trichuris trichiura being the most common, and noted high post-treatment infection rates for various helminths.
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Purpose: Tuberculosis sepsis (TBS) is sepsis due to the Mycobacterium species causing tuberculosis (TB). It seems to be rare in HIV-negative patients and mainly individual case reports have been reported. This systematic review summarizes the epidemiology, clinical features, and treatment outcomes of TBS in HIV-negative patients.

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Controlled human malaria infection (CHMI) using cryopreserved non-attenuated Plasmodium falciparum sporozoites (PfSPZ) offers a unique opportunity to investigate naturally acquired immunity (NAI). By analyzing blood samples from 5 malaria-naïve European and 20 African adults with lifelong exposure to malaria, before, 5, and 11 days after direct venous inoculation (DVI) with Sanaria PfSPZ Challenge, we assessed the immunological patterns associated with control of microscopic and submicroscopic parasitemia. All (5/5) European individuals developed parasitemia as defined by thick blood smear (TBS), but 40% (8/20) of the African individuals controlled their parasitemia, and therefore remained thick blood smear-negative (TBS Africans).

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Background: Vector control is considered to be the most successful component of malaria prevention programs and a major contributor to the reduction of malaria incidence over the last two decades. However, the success of this strategy is threatened by the development of resistance to insecticides and behavioural adaptations of vectors. The aim of this study was to monitor malaria transmission and the distribution of insecticide resistance genes in Anopheles populations from three rural areas of the Moyen Ogooué Province of Gabon.

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The objective of this pilot malacological survey was to identify the snail intermediate hosts for   in endemic rural and semi-urban areas of Gabon. Snails were collected, morphologically identified, and tested for infection by cercarial shedding. Released cercariae were morphologically identified using low-power light microscopy.

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Background: Biomedical research plays an important role in improving health. There seems to exist a negative correlation between the amount of biomedical research funding and disease burden from all Sub-Saharan African countries. In this study, we describe funding patterns for biomedical research, explore the correlation between funding and burden of diseases, and quantify inequalities in funds distribution across diseases in Gabon over the period 2005-2015.

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Article Synopsis
  • Two hookworm vaccine candidates, Na-GST-1 and Na-APR-1, were tested in Gabon and found to be safe and able to induce overall immune responses during a Phase 1 trial.
  • Blood samples from 24 volunteers showed that Na-GST-1 specifically increased CD4+ T cells producing immune-stimulating cytokines after the third vaccination, while Na-APR-1 did not induce similar responses.
  • The study noted that blocking an inhibitory molecule called CTLA-4 led to a stronger immune response in cells responding to Na-GST-1, suggesting this pathway may help improve vaccine effectiveness.
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Article Synopsis
  • The study focused on assessing knowledge, attitudes, and practices related to schistosomiasis in Lambaréné, Gabon, to create a tailored control program for the disease.
  • It involved interviewing 602 participants using standardized questionnaires, revealing that many had contact with freshwater and a significant portion had a history of schistosomiasis diagnosis or praziquantel treatment.
  • Results showed that while the knowledge and attitudes towards the disease were reasonably high (68% and 73% respectively), 60% of participants still engaged in practices that increased their risk of infection.
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Background: Helminths can modulate the host immune response to Plasmodium falciparum and can therefore affect the risk of clinical malaria. We assessed here the effect of helminth infections on both the immunogenicity and efficacy of the GMZ2 malaria vaccine candidate, a recombinant protein consisting of conserved domains of GLURP and MSP3, two asexual blood-stage antigens of P. falciparum.

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Objective: To report the prevalence of polyparasitism during pregnancy in the Lambaréné region of Gabon and its association with newborn birth weight.

Method: Pregnant women in their third trimester were recruited in a prospective study between November 2011 and March 2015. Parasite infection status was assessed microscopically in stool, urine and blood samples.

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Background: Schistosoma antigen detection in urine is a valuable diagnostic approach for schistosomiasis control programmes because of the higher sensitivity compared to parasitological methods and preferred sampling of urine over stool. Highly accurate diagnostics are important in low Schistosoma transmission areas. Pregnant women and young children could particularly benefit from antigen testing as praziquantel (PZQ) can be given to only confirmed Schistosoma cases.

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Gabon carries a high burden of both tuberculosis (TB) and smoking. This study examines the disease characteristics of smoking pulmonary TB patients in Lambaréné. We interviewed adult pulmonary TB patients in Lambaréné, between March 2016 and April 2019.

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Helminth infections are common in sub-Saharan Africa. Besides direct clinical effects, a bias towards a T helper type 2 (Th2) cell immune response is observed. The consequences of parasite infection during pregnancy for the mother and particularly for the fetus and the newborn can be severe and may include impaired immune response during acute infection and vaccination.

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Schistosomiasis is a parasitic infection highly prevalent in Central Africa where it is co-endemic with many other parasitic infections, including soil-transmitted helminths (STHs). For its optimal control, there is a need of descriptive epidemiological data for each endemic region. The objective of the present study was to determine the epidemiological situation around schistosomiasis in Lambaréné, Gabon.

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Background: Malaria remains a major public health problem, affecting mainly low-and middle-income countries. The management of this parasitic disease is challenged by ever increasing drug resistance. This study, investigated the therapeutic efficacy, tolerability and safety of artemether-lumefantrine (AL) and artesunate-amodiaquine (AS-AQ), used as first-line drugs to treat uncomplicated malaria in Lambaréné, Gabon.

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