Search Results (80)

Background: Onchocerciasis, or river blindness, is one of the neglected tropical diseases (NTDs) that the WHO has set out to eliminate. To reach this elimination target, a number of challenges must be met, and the essential measures set out in the road map for NTDs 2021–2030 must be implemented. More than 99% of infected people live in 31 countries in sub-Saharan Africa. Our objective was to assess the impact of onchocerciasis interventions in Africa. Methodology: A systematic peer review of the existing literature following the PRISMA guidelines was performed between November 2021 and April 2022. We selected studies on onchocerciasis control measures in Africa since the implementation of the first Onchocerciasis Control Programme (OCP) measures in 1974. All scientific articles indexed in the PubMed, Scopus, Embase, and CENTRAL databases written in Spanish, English, French, German, and Portuguese were considered. The study protocol was registered in the PROSPERO database. Results: A total of 63 articles met the inclusion criteria and were finally selected. Publications were found from 19 out of 31 African endemic countries. The main intervention retained in the different published studies was mass distribution of ivermectin (n = 51). According to our results, 11 African countries have managed to interrupt transmission of onchocerciasis in at least one area in the country; 11 countries have not achieved this goal, while 1 country has managed to eliminate the disease, but it has resurged. Conclusions: Control interventions showed a positive impact on the fight against onchocerciasis, demonstrating that these activities are effective. Nevertheless, they were not sufficient to achieve the proposed goals for a variety of reasons. Therefore, different aspects should be considered in order to fulfil the targets proposed by the WHO to be reached in 2030. Full article

Background: Neglected tropical diseases (NTDs) are a diverse group of twenty diseases that occur in tropical and subtropical regions that particularly affect vulnerable and often marginalised populations. Five of these are classified as “preventive chemotherapy” (PC) diseases such as trachoma, onchocerciasis, geo-helminthiasis, lymphatic filariasis, and schistosomiasis. This study aimed to describe the knowledge, attitudes, and practices of healthcare providers in the Forecariah health district with respect to PC-NTDs in Guinea in 2022. Methods: A descriptive cross-sectional study was conducted from 7 to 22 November 2022 among healthcare providers in the health district of Forécariah in Guinea. Data on participants’ socio-demographic characteristics and knowledge of and attitudes and practices regarding PC-NTDs were collected using an electronic (KoboToolbox) semi-structured questionnaire and analysed using descriptive statistics. Results: Among the 86 healthcare providers who participated in this study, nurses (44.2%) and young adults aged between 25 and 49 years (81.4%) were mostly represented. The majority of respondents declared having already heard about onchocerciasis (70.7%) and lymphatic filariasis (60.0%) but only the minority declared having already heard about geo-helminthiasis (30.7%), schistosomiasis (21.3%), and trachoma (9.3%). Only a few respondents knew how to prevent PC-NTDs (onchocerciasis 26.7%, lymphatic filariasis 26.7%, geo-helminthiasis 29.3%, and schistosomiasis 17.3%). Many healthcare providers reported they would refer cases of onchocerciasis (50.6%), lymphatic filariasis (58.7%), and schistosomiasis (46.7%) to a management centre. Conclusions: This study highlights the varying levels of knowledge, attitudes, and practices among healthcare providers in dealing with PC-NTDs, suggesting areas for improvement in training and resource allocation. Full article

This prospective survey determined the prevalence and intensity of infections due to geohelminths and the associated risk factors in five onchocerciasis-endemic communities in Gabon between January and February 2020. Onchocerciasis endemicity was confirmed by Ov16 IgG testing. STHs were detected using the Kato–Katz techniques. Prevalence and parasite density were analyzed according to age, sex, and onchocerciasis endemicity. STHs were found in 64.8% of participants and were more common in hypoendemic (80.9%) and hyperendemic (63.9%) onchocerciasis communities (p < 0.01). Ascaris lumbricoides (65.5%), Trichuris trichiura (57.1%), and hookworms (17.3%) were prevalent in areas hypoendemic for onchocerciasis (p = 0.04). Male participants were more often infected by hookworms. Adults were more frequently infected by STHs (75.9%) than elders, who were the least infected (39.3%) (p < 0.01). Participants living in sporadic onchocerciasis areas frequently but not significantly harbored a moderate ascariasis load (6960.0 (1068.0–9492.0) eggs per gram) (p = 0.4). The highest parasite density was observed among participants aged 20–45 years (15,336.0 (3888.0–35,028.0)). A low T. trichiuria prevalence was found in all communities. STHs are highly prevalent in hypoendemic and hyperendemic areas and adults. An integrated combined approach of STH and onchocerciasis elimination through efficacious mass drug administration targeting all age groups should be considered. Full article

Neglected tropical diseases (NTDs) with skin manifestations present a significant health and societal problems challenge worldwide. This study aimed to analyzed factors associated with the knowledge, attitudes and practices (KAPs) of primary healthcare workers (HCW) concerning NTDs with skin manifestations in the Dakar region of Senegal. We conducted a cross-sectional study utilizing a semi-structured questionnaire which was administered to eligible HCW (general practitioners, nurses and midwives) working at the 24 health centers located in the Dakar region. Data were collected using the ODK Collect application (version 2022.3.6). KAPs measures were constructed from questionnaire responses, and bivariate analysis was used to identify associated factors. Of the 187 HCW surveyed, 75.9% were female, with a mean age of 35.1 years (SD: 8.56). The majority of HCWs had a bachelor’s degree (40.6%), were nurses (49.2%) and had between 1- and 10-years of professional experience (52.4%). Regarding their knowledge of NTDs with skin manifestations, only 43.3% of HCW had received initial training on NTDs. The most commonly reported NTDs with skin manifestations were leprosy (53.5%), lymphatic filariasis (51.3%), scabies (49.7%), onchocerciasis (45.5%) and schistosomiasis (42.8%). Television was the main source of information about these NTDs (38.5%). In term of practices, only 47.6% of HCW reported being able to diagnose NTDs with skin. Factors associated with good knowledge regarding NTDs with skin manifestations included having received training on NTDs (p = 0.0015) and more years of professional experience (p = 0.004). In summary, there is a need to strengthen and raise awareness about NTDs with skin manifestations among HCWs and promote quality management of patients in Senegal. Full article

Background: Almost the entire country of Burkina Faso was endemic to onchocerciasis. Onchocerciasis control efforts thus brought the prevalence of O. volvulus to a level where the disease was no longer a public health problem in 2002. A resurgence of onchocerciasis cases has been observed in two regions (Cascades and the Southwest) located around several river basins in 2010–2011. In accordance with WHO guidelines for the management of resurgent cases, community-directed treatment with ivermectin (CDTI) was implemented in the affected areas. The aim of this study was to determine the effects of this intervention on parasitological indices of onchocerciasis, depending on the distance between villages and rivers. Methodology: We conducted a paired pre-post study using aggregated village-level data from two cross-sectional surveys conducted in each region. A Wilcoxon signed-rank test was used to compare the standardized microfilarodermia prevalence and community microfilarial load (CMFL). Results: A total of 43 villages in 6 health districts, in the Southwest (18) and Cascades (25) regions were included in the study. The key findings were that standardized microfilaria prevalence and CMFL decreased significantly after the implementation of CDTI in both regions (p < 0.0001). The median standardized microfilaria prevalence was 2.8 [interquartile range (IQR): 0.2–6.6] before CDTI and 0.72 [IQR: 0.0–2.17] after CDTI. The results showed also a decline in standardized microfilaria prevalence and CMFL in all villages, regardless of the distance separating the village from the streams. However, the results were not statistically significant for the villages located 5 km or more from streams (p = 0.0816 and 0.0542 for standardized microfilaria prevalence and CMFL, respectively). Conclusion: Our results thus show that the implementation of effective CDTI could stop the transmission of O. volvulus in these two regions. The main challenge for stopping transmission could be the migration of populations to neighboring countries and migration of the vector from one country to another, as Burkina Faso shares some river basins with neighboring countries. Full article

Blackfly members of the Simulium damnosum complex are major vectors of the parasite that causes onchocerciasis in Africa and Yemen, with other vector species involved in a few localized areas of Africa and in the Neotropics. Although the life cycle of these blackflies is linked to fast-flowing rivers, they can travel long distances (up to at least 500 km), calling into question how transmission zones are defined. Knowledge of the short- and long-range dispersal of these vectors could inform where control interventions and monitoring are necessary if targets for onchocerciasis elimination are to be met. Yet, research on blackfly dispersal has been limited and fragmented over the last 70 years. Here, we review the literature on the dispersal of onchocerciasis vectors, and we show the need for further research to establish how far larvae can travel downstream; the extent to which adults invade transmission zones; and whether adults migrate in a series of successive short movements or in single long-distance shifts, or use both methods. Full article

Onchocerciasis causes severe morbidity in sub-Saharan Africa. Abia, Anambra, Enugu, and Imo states of Nigeria were historically classified meso- or hyperendemic and eligible for ivermectin mass drug administration (MDA). After ≥25 years of annual and biannual MDA, serological and entomological assessments were conducted to determine if Onchocerca volvulus transmission was interrupted. Dried blood spots collected in October 2020 from ≥3167 children 5–9 years old in each state were screened for O. volvulus-specific Ov16 antibody by enzyme-linked immunosorbent assay. Additionally, 52,187 Simulium damnosum heads (≥8845 per state) collected over 12 months between 2021 and 2022 were tested by pooled polymerase chain reaction (PCR) for O-150 DNA. Among seven seropositive children, four were found for follow-up skin snip PCR to confirm active infection. Three were negative and the fourth was excluded as he was visiting from an endemic state. The final seroprevalence estimates of each state had 95% upper confidence limits (UCL) < 0.1%. All fly pools were negative by O-150 PCR, giving a 95% UCL infective fly prevalence < 0.05% in each state. Each state therefore met the World Health Organization epidemiological and entomological criteria for stopping MDA effective January 2023. With 18.9 million residents eligible for MDA, this marked the largest global onchocerciasis stop-treatment decision to date. Full article

Recent research suggests that infection with Onchocerca volvulus induces neurocognitive decline. This study sought to compare the cognitive outcomes of elderly persons based on onchocerciasis infection status and report the overall prevalence of dementia in the rural Ntui Health District in Cameroon. A community-based approach was used to recruit 103 participants aged ≥60 years. Dementia screening was done using the Community Screening Interview for Dementia (CSID) tool with a cut-off value of ≤29.5. O. volvulus infection was determined via microscopic examination of skin snips and serological testing of Ov16 antibodies using rapid diagnostic tests. Overall, the prevalence of dementia was 10.7%. Among the tested individuals, 17.9% (15/84) and 62.1% (41/66) were positive for O. volvulus and Ov16 antibodies, respectively. A multivariable linear regression model of CSID scores found a significant positive association with education level (8.654; 95% CI: 2.0870 to 15.222). However, having a positive skin snip for O. volvulus (−3.399; 95% CI: −6.805 to 0.007) and inhaling tobacco (−5.441; 95% CI: −9.137 to −1.744) tended to lower the CSID scores. Ongoing onchocerciasis transmission in the Ntui Health District may constitute a risk factor for dementia. Strengthening onchocerciasis elimination and adopting healthier lifestyles would contribute to dementia prevention among the elderly residing in endemic communities. Full article

Besides being vectors of the onchocerciasis parasite, blackflies are a source of nuisance in onchocerciasis-endemic communities. We investigated the experience of residents in the Ntui Health District (Cameroon) regarding blackfly nuisance and assessed their perceptions of a novel “Slash and Clear” (S&C) intervention for blackfly control. Focus group discussions were conducted before and after S&C implementation (respectively, in February 2022 and December 2023). Blackflies were known to emerge from the river areas and cause disease. To prevent blackfly bites, the population often covered their body with protective clothing and applied various substances (kerosene, oil, or lemon) to their skin. Post-intervention data showed reduced blackfly nuisance, and the willingness to sustain blackfly control in the long-term was unanimous among community leaders and members, including the village volunteers who implemented the S&C intervention. In conclusion, blackfly nuisance is evident in the Ntui onchocerciasis focus of Cameroon and led to a panoply of coping practices, some of which could be detrimental to their health. Implementing S&C for blackfly control is well accepted and could sustainably alleviate the nuisance caused by blackflies while simultaneously breaking the onchocerciasis transmission cycle. Full article

Bacillus and related genera are among the most important contaminants in the pharmaceutical production environment, and the identification of these microorganisms at the species level assists in the investigation of sources of contamination and in preventive and corrective decision making. The aim of this study was to evaluate three methodologies for the characterization of endospore-forming aerobic bacterial strains isolated from a pharmaceutical unit in Rio de Janeiro, Brazil. MALDI-TOF MS was performed using MALDI Biotyper^® and VITEK^® MS RUO systems, and complete 16S rRNA gene sequencing was performed using the Sanger methodology. The results showed the prevalence of the genera Bacillus (n = 9; 36.0%), Priestia (n = 5; 20.0%), and Paenibacillus (n = 4; 16.0%). Three (20.0%) strains showed <98.7% of DNA sequencing similarity on the EzBioCloud Database, indicating possible new species. In addition, the reclassification of Bacillus pseudoflexus to the genus Priestia as Priestia pseudoflexus sp. nov. is proposed. In conclusion, 16S rRNA and MALDI TOF/MS were not sufficient to identify all strains at the species level, and complementary analyses were necessary. Full article

Despite several decades of mass drug administration and elimination-related activities, human onchocerciasis still represents a major parasitic threat in endemic regions. Among the challenges encountered by the elimination program is the lack of a suitable diagnostic tool that is accurate and non-invasive. Currently used methods are either invasive or not suitable for monitoring large numbers of patients. Herein, we describe the identification and characterization of Onchocerca volvulus heat shock protein 70 (OvHSP70) as a novel diagnostic biomarker for human onchocerciasis, which can directly be detected in urine samples of infected patients. This nematode-specific antigen was identified through LC-MS after differential SDS-PAGE using urine-derived protein extracts from O. volvulus-infected patients in Cameroon. Polyclonal antibodies generated in rabbits after cloning and expression of OvHSP70 in Escherichia coli reliably differentiated between urine samples from infected- and uninfected patients in a hypoendemic area of human onchocerciasis. These results provide an excellent basis for further development of a non-invasive and scalable diagnostic assay for human onchocerciasis using urine samples. Such a urine-based diagnostic assay will be of major importance for the elimination program of human onchcerciasis in endemic countries. Full article

Onchocerciasis, or river blindness, has historically been one of the most important causes of blindness worldwide, and a major cause of socio-economic disruption, particularly in sub-Saharan Africa. Its importance as a cause of morbidity and an impediment to economic development in some of the poorest countries in the world motivated the international community to implement several programs to control or eliminate this scourge. Initially, these involved reducing transmission of the causative agent Onchocerca volvulus through controlling the vector population. When ivermectin was found to be a very effective drug for treating onchocerciasis, the strategy shifted to mass drug administration (MDA) of endemic communities. In some countries, both vector control and ivermectin MDA have been used together. However, traditional vector control methods involve treating rivers in which the black fly vectors breed with insecticides, a process which is expensive, requires trained personnel to administer, and can be ecologically harmful. In this review, we discuss recent research into alternatives to riverine insecticide treatment, which are inexpensive, ecologically less harmful, and can be implemented by the affected communities themselves. These can dramatically reduce vector densities and, when combined with ivermectin MDA, can accelerate the time to elimination when compared to MDA alone. Full article

This overview initially describes insect immune reactions and then brings together present knowledge of the interactions of vector insects with their invading parasites and pathogens. It is a way of introducing this Special Issue with subsequent papers presenting the latest details of these interactions in each particular group of vectors. Hopefully, this paper will fill a void in the literature since brief descriptions of vector immunity have now been brought together in one publication and could form a starting point for those interested and new to this important area. Descriptions are given on the immune reactions of mosquitoes, blackflies, sandflies, tsetse flies, lice, fleas and triatomine bugs. Cellular and humoral defences are described separately but emphasis is made on the co-operation of these processes in the completed immune response. The paper also emphasises the need for great care in extracting haemocytes for subsequent study as appreciation of their fragile nature is often overlooked with the non-sterile media, smearing techniques and excessive centrifugation sometimes used. The potential vital role of eicosanoids in the instigation of many of the immune reactions described is also discussed. Finally, the priming of the immune system, mainly in mosquitoes, is considered and one possible mechanism is presented. Full article