Assessment of genetic polymorphisms associated with malaria antifolate resistance among the population of Libreville, Gabon

BACKGROUND

Gabon is a malaria-threatened country with a stable and hyperendemic transmission of Plasmodium falciparum monoinfection. Malaria drug resistance is widely spread in many endemic countries around the world, including Gabon. The molecular surveillance of drug resistance to antifolates and artemisinin-based combination therapy (ACT) is one of the strategies for combating malaria. As Plasmodium parasites continue to develop resistance to currently available anti-malarial drugs, this study evaluated the frequency of the polymorphisms and genetic diversity associated with this phenomenon among the parasites isolates in Gabon.

METHODS

To assess the spread of resistant haplotypes among the malaria-infected population of Libreville, single nucleotide polymorphisms linked to sulfadoxine-pyrimethamine (SP) and artemisinin drugs resistance were screened for P. falciparum dihydrofolate reductase (Pfdhfr), P. falciparum dihydropteroate synthase (Pfdhps), and P. falciparum kelch 13-propeller domain (Pfk13) point mutations.

RESULTS

The analysis of 70 malaria-positive patient samples screened for polymorphism showed 92.65% (n = 63) mutants vs. 7.35% (n = 5) wild parasite population in Pfdhfr, with high prevalence mutations at S₁₀₈N(88.24%, n = 60), N₅₁I(85.29%, n = 58), C₅₉R(79.41%, n = 54); however, I₁₆₄L(2.94%, n = 2) showed low frequency mutation. No wild haplotype existed for Pfdhps, and there were no mutations at the K₅₄₀E, A₅₈₁G, and A₆₁₃T/S positions. However, the mutation rate at A₄₃₇G(93.38%, n = 62) was the highest, followed by S₄₃₆A/F(15.38%, n = 10). A higher frequency of quadruple IRNI-SGKAA (69.84%) than quintuple IRNI-(A/F)GKAA (7.94%) mutations was observed in the Pfdhfr-Pfdhps combination. Furthermore, none of the mutations associated with ACT resistance, especially those commonly found in Africa, were observed in Pfk13.

CONCLUSIONS

High polymorphism frequencies of Pfdhfr and Pfdhps genes were observed, with alternative alanine/phenylalanine mutation at S₄₃₆A/F (7.69%, n = 5) for the first time. Similar to that of other areas of the country, the patterns of multiple polymorphisms were consistent with selection owing to drug pressure. Although there was no evidence of a medication failure haplotype in the studied population, ACT drug efficacy should be regularly monitored in Libreville, Gabon.

Severe COVID-19 in 2 Kidney Transplant Patients in Gabon

BACKGROUND Kidney failure is a public health problem that may require transplantation for patient survival and for those at risk of developing infectious diseases such as COVID-19 due to severe immunosuppression. We report the case of 2 kidney transplant patients who contracted COVID-19. CASE REPORT Patient 1: A 60-year-old Gabonese man presented with 8 days of wet cough, fever, and myalgias associated secondarily with dyspnea, without anosmia or ageusia. His medical history included renal transplant for malignant nephro-angiosclerosis and high blood pressure. The oxygen saturation level subsequently fell to 89-90%. The diagnosis of acute hypoxic respiratory failure secondary to COVID-19 pneumonia with heart and acute renal failure on renal transplant was made based on clinical symptoms, lung imaging results, and a positive SARS-CoV-2 nasal swab PCR test. Patient 2: A 79-year-old Gabonese man presented with 10 days of dry cough associated with intermittent fevers not quantified, anorexia, and fatigue. The patient's medical history was high blood pressure, diabetes mellitus, and renal transplantation. Oxygen saturation level decreased to 85-89% in ambient air. Clinical signs and chest CT scan showed 70% lung lesions with large areas of ground-glass opacity with essentially peripheral distribution of both lungs associated with crazy paving, condensation, bronchiectasis, and arterial dilatation, suggesting severe COVID-19. CONCLUSIONS Those 2 presentations highlight the fact that a severe clinical form of COVID-19 associated with acute renal failure and kidney transplant can be fatal. Kidney transplantation is a risk factor for poor prognosis in patients with severe COVID-19 and greatly worsens the mortality rate of immunocompromised patients.

Evaluation of HIV-1 rapid diagnostic tests in the context of viral genetic diversity in Libreville (Gabon)

Introduction

in order to promote rapid care of HIV-positive people and to reduce the human immunodeficiency virus (HIV) transmission in Gabon, the national screening algorithm is essentially based on rapid diagnostic tests (RDTs). However, most of these RDTs are not evaluated. Their sensitivities and specificities remain unknown locally. The aim of this study was to determine the diagnostic performance of 3 RDTs used for HIV-1> screening in Gabon.

Methods

of the one hundred and sixteen (116) samples tested, 60 plasmas were HIV-1 positive with known genotypes and viral loads; 51 sera were HIV-1 negative while 5 had an undetermined serological status. All the samples were tested by quantitative RT-PCR (Gold standard) and by the following RDTs: Vikia, Alere Combo and Alere Determine. The sensitivities and specificities of the different RDTs were calculated using Epi Info version 6.04dfr. The level of agreement between tests was determined by Cohen´s Kappa test.

Results

the three RDTs´ sensitivity according to HIV-1/M subtypes was 100% (95% CI: 92.6-100) while their specificities ranged from 94.6% (95% CI: 84.2-98.6) for the Vikia test to 96.4% (95% CI: 86.6-99.4) for the Alere Combo and Alere Determine tests, respectively. The concordances between the three RDTs were excellent with kappa values ranging from 0.931 (95% CI: 0.864-0.977) to 0.948 (95% CI: 0.890-1.00).

Conclusion

the three RDTs showed a maximum sensitivity of 100% and specificities ranging from 94.6% to 96.4%. The specificities obtained with these RDTs are lower than those recommended by the WHO for their inclusion in an HIV-1 screening algorithm.

Demographic and Clinical Characteristics Associated With Severity, Clinical Outcomes, and Mortality of COVID-19 Infection in Gabon

IMPORTANCE

Since the emergence of COVID-19 in central China, sub-Saharan African countries, with the exception of South Africa, have been relatively spared during the COVID-19 pandemic. Consequently, few descriptive studies from this region are available.

OBJECTIVE

To describe the clinical characteristics and outcomes of patients with COVID-19 infection in Gabon, from March to June 2020.

DESIGN, SETTING, AND PARTICIPANTS

A single-center, cross-sectional study of 837 patients with COVID-19 was conducted from March to June 2020 in the Armed Forces Hospital in Libreville, Gabon.

MAIN OUTCOMES AND MEASURES

Demographic and clinical characteristics and imaging findings of hospitalized patients with COVID-19.

RESULTS

Of the 837 patients enrolled, 572 (68.3%) were men, and 264 (31.5%) were women (male to female ratio, 2:1); the median (interquartile range [IQR]) age was 35 (30-45) years (mean [SD] age, 38.0 [12.2] years. The mortality rate associated with COVID-19 was low (1.4%). Of these 837 patients, 524 (62.6%) were categorized as having no symptoms, 282 (33.7%) as having mild symptoms, and 31 (3.7%) as having severe symptoms. Patients with severe symptoms were older (mean [SD] age, 46.1 [14.7] years) than patients with mild symptoms (mean [SD] age, 41.3 [12.5] years) and those with no symptoms (mean [SD] age, 35.7 [11.3] years) (Kruskal-Wallis χ22 = 53.5; P < .001). History of diabetes was the principal risk factor associated with both severe symptoms in 5 of 31 patients (16.1%) and mild symptoms in 11 of 282 (3.9%) compared with no symptoms in 5 of 524 (0.9%) (Pearson χ22 = 30.9; P < .001). Patients with severe symptoms and a fatal outcome were older (mean [SD] age, 53.4 [15.1] years) than survivors (mean [SD] age, 41.5 [12.9] years) (t20.83 = 2.2; P = .03).

CONCLUSIONS AND RELEVANCE

In this single-center, cross-sectional study in Libreville, Gabon, the mortality rate associated with COVID-19 infection from March to June 2020 was low, and patients who died of COVID-19 infection were younger on average than reported elsewhere, possibly reflecting a smaller elderly population in Gabon.

Human African trypanosomiasis in two historical foci of the estuaire province, gabon: A case report

Human African Trypanosomiasis (HAT) is an infectious disease due to a protozoa parasite of the Trypanosoma genus. In West and Central Africa, this disease is caused by the subspecies Trypanosoma brucei gambiense. Several foci of this disease are currently active and causing the death of hundreds of people in endemic areas. In this article, we report two cases of gambiense HAT in one Indonesian and one Gabonese men in two historical foci of Gabon in 2019. Both patients had fever with temperatures above 38°C, an altered state of consciousness, cachexia, and multiple dermabrasions on the abdomen related to scratching lesions. The diagnostic revealed second-stage infection of both patients with T. b. gambiense; this result was confirmed by a polymerase chain reaction assay. Despite treatment with a combination of eflornithine and nifurtimox, as recommended by the World Health Organization for late-stage T. b. gambiense HAT, one of the two patients died. Thus, these cases highlight the importance of early HAT diagnosis and prompt patient care to fight effectively against this disease.

Takayasu Arteritis Associated with Latent Tuberculosis Infection: A 39-Year-Old Woman Is the First Case in Gabon

Patient: Female, 39-year-old

Final Diagnosis: Takayasu arteritis

Symptoms: Fever • arthralgia • asthenia

Medication: —

Clinical Procedure: —

Specialty: Infectious Diseases