Insecticide resistance status of Aedes aegypti in Southern and Northern Ghana

Background: Outbreaks of Aedes-borne arboviral diseases are becoming rampant in Africa. In Ghana, there is no organized arboviral control programme with interventions restricted to mitigate outbreaks. Insecticide application is a crucial part of outbreak responses and future preventative control measures. Thus, knowledge of the resistance status and underlying mechanisms of Aedes populations is required to ensure optimal insecticide choices. The present study assessed the insecticide resistance status of Aedes aegypti populations from southern Ghana (Accra, Tema and Ada Foah) and northern Ghana (Navrongo) respectively. Methods: Phenotypic resistance was determined with WHO susceptibility tests using Ae. aegypti collected as larvae and reared into adults. Knockdown resistance (kdr) mutations were detected using allele-specific PCR. Synergist assays were performed with piperonyl butoxide (PBO) to investigate the possible involvement of metabolic mechanisms in resistance phenotypes. Results: Resistance to DDT was moderate to high across sites (11.3% to 75.8%) and for the pyrethroids, deltamethrin and permethrin, moderate resistance was detected (62.5% to 88.8%). The 1534C kdr and 1016I kdr alleles were common in all sites (0.65 to 1) and may be on a trajectory toward fixation. In addition, a third kdr mutant, V410L, was detected at lower frequencies (0.03 to 0.31). Pre-exposure to PBO significantly increased the susceptibility of Ae. aegypti to deltamethrin and permethrin (P<0.001). This indicates that in addition to kdr mutants, metabolic enzymes (monooxygenases) may be involved in the resistance phenotypes observed in the Ae. aegypti populations in these sites. Conclusion: Insecticide resistance underpinned by multiple mechanisms in Ae. aegypti indicates the need for surveillance to assist in developing appropriate vector control strategies for arboviral disease control in Ghana. Keywords: insecticide resistance, target-site mutations, Aedes aegypti, Piperonyl butoxide Synergist, knockdown resistance, Ghana

A diverse spectrum of mycoses histologically diagnosed in Ghana:Insights from a 10-year retrospective study

In Ghana, most laboratory diagnoses of severe mycoses are based on histopathology findings due to inadequate availability of serology, culture, and molecular tests. The aim of this study was to evaluate the spectrum of mycoses diagnosed in Ghana. We retrospectively reviewed reports from 2012 to 2021 from three major pathology laboratories in Ghana to identify reports indicating the presence of fungal elements and diagnosis of a mycosis, then extracted demographic, clinical history, site of infection, stain(s), used and diagnosed mycosis details. Over the 10-year period, 107 cases were found. No apparent increasing and decreasing trend in the number of cases per year or in a period was observed. The age range of affected patients was from 4 to 86 years. Special stains for fungi were only used in 22 of 107 (20.6%) of cases. The most frequently affected site was the sino-nasal area (34%). Mycosis type was determined for 58 (54.2%) cases, comprising aspergillosis (21), candidiasis (14), dermatophytosis (6), mucormycosis (3), two cases each of chromoblastomycosis, histoplasmosis, eumycetoma, entomophthoromycosis, sporotrichosis, and Malassezia infection and a single case each of cryptococcosis and deep onychomycosis. Of the 53 (49.5%) cases with presumptive diagnosis data, only seven (13.2%) had a pre-biopsy suspicion of mycosis. There is a wide spectrum of mycoses in Ghana, including endemic mycoses not previously reported. Improving the use of special fungal stains could increase yield and mycoses identification. Laboratory diagnostic capacity needs enhancement to complement histopathology investigations with serology, culture, and molecular methods.</p

Detection of Invasive Anopheles stephensi Mosquitoes through Molecular Surveillance, Ghana

The invasive Anopheles stephensi mosquito has rapidly expanded in range in Africa over the past decade. Consistent with World Health Organization guidelines, routine entomologic surveillance of malaria vectors in Accra, Ghana, now includes morphologic and molecular surveillance of An. stephensi mosquitoes. We report detection of An. stephensi mosquitoes in Ghana

Insecticide resistance status of Aedes aegypti in southern and northern Ghana

Abstract Background Outbreaks of Aedes-borne arboviral diseases are becoming rampant in Africa. In Ghana, there is no organized arboviral control programme with interventions restricted to mitigate outbreaks. Insecticide application is a crucial part of outbreak responses and future preventative control measures. Thus, knowledge of the resistance status and underlying mechanisms of Aedes populations is required to ensure optimal insecticide choices. The present study assessed the insecticide resistance status of Aedes aegypti populations from southern Ghana (Accra, Tema and Ada Foah) and northern Ghana (Navrongo) respectively. Methods Phenotypic resistance was determined with WHO susceptibility tests using Ae. aegypti collected as larvae and reared into adults. Knockdown resistance (kdr) mutations were detected using allele-specific PCR. Synergist assays were performed with piperonyl butoxide (PBO) to investigate the possible involvement of metabolic mechanisms in resistance phenotypes. Results Resistance to DDT was moderate to high across sites (11.3 to 75.8%) and, for the pyrethroids deltamethrin and permethrin, moderate resistance was detected (62.5 to 88.8%). The 1534C kdr and 1016I kdr alleles were common in all sites (0.65 to 1) and may be on a trajectory toward fixation. In addition, a third kdr mutant, V410L, was detected at lower frequencies (0.03 to 0.31). Pre-exposure to PBO significantly increased the susceptibility of Ae. aegypti to deltamethrin and permethrin (P < 0.001). This indicates that in addition to kdr mutants, metabolic enzymes (monooxygenases) may be involved in the resistance phenotypes observed in the Ae. aegypti populations in these sites. Conclusion Insecticide resistance underpinned by multiple mechanisms in Ae. aegypti indicates the need for surveillance to assist in developing appropriate vector control strategies for arboviral disease control in Ghana. Graphical Abstrac

Coverage of preventive measures and surveillance for neglected tropical diseases in hard-to-reach communities in Ghana

Abstract Background Neglected tropical diseases (NTDs) are a major public health burden which mainly affects poor populations living in tropical environments and hard-to-reach areas. The study sought to examine coverage of preventive efforts, and case surveillance for NTDs in hard-to-reach communities in Ghana. Methods The study investigated treatment efforts for lymphatic filariasis (LF), and onchocerciasis and schistosomiasis/soil transmitted helminths (SCH/STH) at household level, in difficult-to-access communities in Ghana. A total of 621 households were sampled from 6 communities in the Western, Oti and Greater Accra regions. Results Over 95% of the households surveyed were covered under mass drug administration (MDA) campaigns for lymphatic filariasis (LF) and onchocerciasis. More than 80% of households had received at least two visits by community drug distributors under the MDA campaigns in the last two years preceding the study. In addition, over 90% of households in the LF and onchocerciasis endemic communities had at least one member using anthelminthic medications under the MDA campaigns in the 12 months preceding the study. However, households where no member had taken anthelminthic medications in 12 months preceding the study were over 6 times likely to have someone in the household with LF. Conclusions This study determined that SCH/STH, LF and onchocerciasis are of serious public health concern in some communities in Ghana. There is an urgent need for holistic practical disease control plan involving both financial and community support to ensure total control of NTDs in difficult-to-access communities is achieved

Additional file 1 of Coverage of preventive measures and surveillance for neglected tropical diseases in hard-to-reach communities in Ghana

Additional file 1: S1. File Household Questionnaire-2