Onchocerciasis control in Ghana (1974-2016)

Association of haemato-biochemical indices and blood composite ratios with microfilaridermia in Onchocerciasis patients

BACKGROUND

Onchocerciasis causes chronic systemic inflammation. Several studies have used markers such as haemato-biochemical indices to predict the occurrence of systemic inflammation. This study assessed the variability and predictability of haemato-biochemical indices and blood composite ratios (BCRs) in microfilariae positive (MF+) and microfilariae negative (MF-) subgroups of onchocercomata participants.

METHODS

One hundred and five (105) MF + and 34 MF- participants were retrospectively recruited into the study. Screening for the presence of O. volvulus microfilariae was done from skin snips taken from the left and right iliac crests of participants using established and approved protocols. Haematological and biochemical indices were measured using standard laboratory automated analyzers. Blood composite ratios (BCRs) were calculated as ratios of the absolute parameters involved.

RESULTS

A significantly increased total WBC, absolute eosinophil, eosinophil percent and absolute basophil were observed in the MF + participants compared to MF- participants. Reduced gamma-glutamyl transferase (GGT) with increased estimated glomerular filtration rate (eGFR) was significantly associated with MF + participants compared to MF- participants. BCRs were significantly higher for eosinophil-to-neutrophil ratio (ENR), eosinophil-to-monocyte ratio (EMR), eosinophil-to-basophil ratio (EBR) and eosinophil-to-lymphocyte ratio (ELR) in MF + participants compared to MF- participants. After multivariate adjustment, onchocercomata participants with increased eosinophil counts (aOR = 13.86, 95% CI [2.07-92.90], p = 0.007), ENR x10 (aOR = 1.42, 95% CI [1.05-1.93], p = 0.025), EMR (aOR = 2.64, 95% CI [1.25-5.60], p = 0.011), EBR (aOR = 1.07, 95% CI [1.01-1.10], p = 0.020) and ELR x10 (aOR = 1.69, 95% CI [1.14-2.51], p = 0.009) were more likely to have microfilaridermia.

CONCLUSIONS

Elevated eosinophil counts with higher ENR, EMR, EBR and ELR levels are significantly associated with microfilaridermia in onchocercomata participants. Combining BCRs with eosinophil count significantly led to an improvement in the conventional model for predicting microfilaridermia.

Non-adherence to ivermectin in onchocerciasis-endemic communities with persistent infection in the Bono Region of Ghana: a mixed-methods study

BACKGROUND

The World Health Organization has proposed that onchocerciasis elimination (interruption) of transmission be verified in 12 (approximately a third) endemic countries by 2030. The strategy to reach this goal is based on ivermectin Mass Drug Administration (MDA) with high geographical and therapeutic coverage. In addition to coverage, high levels of treatment adherence are paramount. We investigated factors associated with ivermectin intake in an area of Ghana with persistent Onchocerca volvulus infection.

METHODS

In August 2021, a cross-sectional mixed-methods study was conducted in 13 onchocerciasis-endemic communities in the Bono Region of Ghana. Individuals aged ≥ 10 years were invited to participate in a questionnaire survey. A total of 48 focus group discussions and in-depth interviews with 10 community drug distributors and 13 community leaders were conducted.

RESULTS

A total of 510 people participated in the study [median age: 32, interquartile range 30 (20‒50) years]; 274 (53.7%) were females. Of the total, 320 (62.7%) declared that they adhered to each treatment round and 190 (37.3%) admitted they had not taken ivermectin during at least one MDA round, since becoming eligible for treatment. Of 483 participants with complete information, 139 (28.8%) did not take ivermectin during the last round (March 2021), and 24 (5.0%) had never taken ivermectin (systematic non-adherers). Reasons for not taking ivermectin included previous experience/fear of side-effects, being absent during MDA, pregnancy, the desire to drink alcohol, and drug distribution challenges. Being male, having good knowledge and perception of the disease, and not having secondary or higher level of formal education were significantly associated with higher odds of ivermectin intake.

CONCLUSIONS

A relatively high level of non-adherence to ivermectin treatment was documented. There is a need for targeted educational and behavioural change campaigns to reverse these trends and ensure a steady course toward meeting onchocerciasis elimination targets in Ghana.

Persistence of onchocerciasis and associated dermatologic and ophthalmic pathologies after 27 years of ivermectin mass drug administration in the middle belt of Ghana

OBJECTIVES

There is a pressing need to regularly evaluate the progress of onchocerciasis elimination programmes to timely identify and mitigate potential risks hindering the reaching of the 2030 targets proposed by the World Health Organization (WHO) in its roadmap on neglected tropical diseases (NTDs). We determined the prevalence of onchocerciasis and associated dermatological and ophthalmological manifestations in six endemic communities in the Bono Region of Ghana after 27 years of ivermectin mass treatment.

METHODS

In a cross-sectional study, 564 participants aged ≥5 years were enrolled (49.1% females), with a median age of 26 (range: 5-89) years. In 54% and 47%, skin-snip microscopy and Ov16 rapid diagnostic tests were performed, respectively. Skin disease was determined using the WHO Skin NTD App. Visual function assessments included tests of visual acuity.

RESULTS

The overall microfilarial prevalence was 12.5% (38/305) and Ov16 seroprevalence was 24.2% (64/265). Severe itching was recorded in 24.3%, acute papular onchodermatitis in 52.8%, chronic papular onchodermatitis in 12.5%, lichenified onchodermatitis in 0.7%, skin atrophy in 11.3%, depigmentation in 1.7% and palpable nodules in 5.3%. Of the 301 persons in which visual acuity was examined, 17% were visually impaired and 5.3% were blind and 47.3% presented with cataract. Chronic papular onchodermatitis, lichenified onchodermatitis, depigmentation and visual impairment were significantly associated with the presence of skin microfilariae and Ov16 seropositivity.

CONCLUSIONS

The persistence of Onchocerca volvulus infection and onchocerciasis-associated dermatological and ophthalmological pathologies after prolonged treatment is of concern. There is a need to include morbidity management in onchocerciasis elimination programmes and understand better patterns of treatment coverage, adherence and actual intake of ivermectin.

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

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.

Prevalence of epilepsy in the onchocerciasis endemic middle belt of Ghana after 27 years of mass drug administration with ivermectin

BACKGROUND

In onchocerciasis-endemic areas with high ongoing Onchocerca volvulus transmission, a high prevalence of epilepsy has been reported. This study aimed to determine the prevalence and clinical characteristics of epilepsy in the Bono Region of Ghana following 27 years of implementation of ivermectin mass drug administration (MDA).

METHODS

Between October 2020 and August 2021, cross-sectional surveys were conducted in nine communities in the Tain District and Wenchi Municipality of the Bono Region of Ghana. In the first stage, a random door-to-door approach was used to screen the population for epilepsy using a pre-tested questionnaire. Persons suspected of having epilepsy were invited for a second-stage neurological examination for case verification. Community O. volvulus microfilarial infection status and Ov16 seropositivity were also determined. Ninety-five confidence intervals (95% CI) for prevalence values were calculated using the Wilson Score Interval.

RESULTS

Of the 971 participants, 500 (51.5%) were females, and the median age (interquartile range) was 26 (15‒43) years. Fourteen participants (1.4%, 95% CI: 1.0‒2.0) were diagnosed as having epilepsy with generalized seizures being the most frequent seizure type (85.7%, 12/14). The overall microfilarial prevalence of O. volvulus was 10.3% (November 2020) and 9.9% (August 2021); the Ov16 seroprevalence was 22.2% (June 2021). Only 63.2% took ivermectin in the last round of MDA distribution in March 2021.

CONCLUSIONS

The 1.4% prevalence of epilepsy in the Bono region is similar to the median epilepsy prevalence in sub-Saharan Africa. However, the persistent microfilarial prevalence and low ivermectin study coverage call for the Ghana Onchocerciasis Elimination Programme to step up its efforts to ensure that the gains achieved are consolidated and improved to achieve the elimination of onchocerciasis by 2030.

Management of onchocerciasis among adolescents in nkwanta north district of Ghana: Qualitative study of adolescents' perception, community and health system support

BACKGROUND

Onchocerciasis affects the quality of life to a greater extent among affected individuals. The World Health Organization (WHO)'s Onchocerciasis Control Program (OCP) has effectively reduced the prevalence of onchocerciasis by interrupting the transmission of the parasite and by mass population treatment in the regions at risk of the disease. Despite the successful reduction of the prevalence of onchocerciasis by WHO, the socioeconomic burden resulting from the disabilities caused by onchocerciasis are still immense. This study sought to explore the adolescents' perception regarding the management of onchocerciasis, community and health system support in Nkwanta North District of Ghana.

METHOD

This study adopted a qualitative phenomenological design and exploratory, descriptive qualitative approach. An in-depth interview guide was developed to collect data for the study. One-on-one interview was conducted. Data collected from 16 onchocerciasis adolescent patients were analysed thematically using ATLAS.ti v7.5.7. Quotes from the participants were presented verbatim to substantiate the themes realised.

RESULTS

Most of the 12 participants (75.0%) were aged 15-18 years old. It was noted that 6(37.50%) of participants were in Junior High School (JHS), while 4(25.0%) were in Senior High School (SHS). It was noted that community members have diverse understandings and perceptions of onchocerciasis, including beliefs that Onchocerciasis is a serious disease that can cause blindness; it is caused by the consumption of some types of food products or stressful work. Adolescents believed that onchocerciasis was caused by insect bite blood infection, poor environmental hygiene, sun or could have been inherited from parents. Ivermectin treatment was noted by adolescents to have helped relieve the symptoms of ochocerciasis they were experiencing. However, the adolescents indicated that they had experienced some side effects, including fever, headache, body itching, rushes, swollen body and blurred vision from the drug.

CONCLUSION

Inadequate education and communication about onchocerciasis resulted in diverse and erroneous meanings of onchocerciasis among community members. Our research recognises that community and health system supports is very important in the effective management of Onchocerciasis, contributing to the attainment of Sustainable Development Goal (SDG) 3.3, which is targeted at ending the epidemic of NTDs like onchocerciasis by 2030.

Mortality among persons with epilepsy in onchocerciasis-endemic and non-endemic areas of sub-Saharan Africa: A systematic review and meta-analysis

PURPOSE

To document epilepsy-related mortality in sub-Saharan Africa (SSA) and investigate possible associations with onchocerciasis endemicity.

METHODS

Systematic review with meta-analysis. Searches were performed in PubMed and Google Scholar (search terms: 'epilepsy'; 'mortality/death'; 'sub-Saharan Africa'). Included studies were classified as high-risk or low-risk for onchocerciasis based on documented endemicity data. Pooled mortality rates and annual case fatality rates (CFR) were calculated, and risk factors for mortality among persons with epilepsy (PWE) were investigated using meta-regression analysis.

RESULTS

The 28 eligible studies reported 30 epilepsy surveys, of which 9 (30.0%) were conducted in onchocerciasis high-risk sites. The pooled epilepsy mortality rate was 20.9 (95% CI: 5.9-74.4) per 100,000 person-years, and the pooled CFR was 36.2 (95% CI: 23.9-54.4) per 1,000 PWE per year, albeit with substantial between-study heterogeneity. Compared to onchocerciasis low-risk sites, high-risk sites had higher pooled mortality (342.9 versus 10.0 per 100,000 PY; p<0.001) and CFR (57.0 versus 26.6 per 1,000 PWE per year; p = 0.001). Mortality of PWE was almost five-fold that of people without epilepsy (mortality risk ratio: 4.9; 95% CI: 3.5-6.8). Studies in onchocerciasis high-risk sites and the study which recruited only PWE with nodding syndrome were associated with higher CFR (p = 0.044 and p = 0.002, respectively). The leading causes of epilepsy-related death were status epilepticus (58.5%), drowning (15.7%), and sudden unexpected death in epilepsy (10.1%).

CONCLUSION

Epilepsy mortality remains high in SSA. Most reported causes of death among PWE might be averted by improving seizure control. Better epilepsy prevention and care are urgently needed, particularly in onchocerciasis-endemic settings.

Occurrence of Lymphatic Filariasis infection after 15 years of mass drug administration in two hotspot districts in the Upper East Region of Ghana

Background

Lymphatic filariasis (LF) causes chronic morbidity, which usually manifests as lymphedema or hydrocele. Mass drug administration (MDA) began in Kassena Nankana East Municipal (KNEM) and Nabdam, two hotspot districts in the Upper East Region in Ghana, in 2000 and 2005, respectively. This cross-sectional study evaluated the impact of 15 years of MDA on the control of LF as determined by circulating filarial antigen (CFA) and microfilariae assessment in the KNEM and the Nabdam districts.

Methodology/Principal findings

A total of 7,453 participants from eight sub-districts in the two hotspot districts (KNEM: N = 4604; Nabdam: N = 2849) were recruited into the study. The overall CFA prevalence as determined by the FTS was 19.6% and 12.8% in the KNEM and Nabdam districts, respectively. Manyoro, a sub-district on the border with Burkina Faso, recorded the highest CFA prevalence of 26% in the KNEM. Assessment of microfilariae and Og4C3 antigen was done from 1009 (KNEM: N = 799 (79.2%); Nabdam: N = 210 (20.8%)) randomly selected FTS-positive (N = 885) and FTS-negative (N = 124) individuals. The Og4C3 antigen was found in 22.6%/23.0% of the selected individuals (KNEM/Nabdam), whereas the night blood revealed microfilariae in only 0.7%/0.5%.

Conclusions/Significance

Using the WHO endorsed FTS, CFA prevalence exceeded the long-standing <2% threshold—which may need revision and validation. Surprisingly, the Og4C3 ELISA showed positive results in only about one-fifth of the FTS positive samples. However, even this result would not have met the <2% CFA criteria for LF elimination. In contrast, projections from the microfilariae results revealed a halt in LF transmission. The global elimination target was due in 2020 but has been extended to 2030 since this could not be met. Focused MDA intervention intensification on seasonal migrants and non-compliers, and implementation of alternative treatment strategies may suffice for the elimination of the disease.

Lymphatic filariasis (LF) is a major neglected tropical disease (NTD) affecting over 120 million individuals worldwide and identified as one of WHO’s 20 NTDs targeted for elimination. It has strong links with poverty and is associated with significant clinical morbidity, which impose considerable socio-psychological and economic burdens on the affected individuals. One of the main goals of the Global Programme to Eliminate Lymphatic Filariasis (GPELF) is the use of mass drug administration (MDA) to interrupt LF transmission. The initial 2020 elimination target year set by the GPELF could not be met, with 2030 now the new proposed year targeted for global elimination. The study evaluated the impact of 15 years of MDA on the control of LF in two hotspot districts in Ghana. The results from this study are indicative of a halt in LF transmission in the districts, with microfilaria detected in <1% of those sampled. However, the antigenemia prevalence is still above the recommended level. MDA should be intensified especially at the border towns or alternative treatment strategies should be employed to finally eliminate the disease as some people who are still with the active infection can serve as a reservoir for recrudescence and transmission in already “LF-free” areas.

Demographic patterns of human antibody levels to Simulium damnosum s.l. saliva in onchocerciasis-endemic areas: An indicator of exposure to vector bites

BACKGROUND

In onchocerciasis endemic areas in Africa, heterogenous biting rates by blackfly vectors on humans are assumed to partially explain age- and sex-dependent infection patterns with Onchocerca volvulus. To underpin these assumptions and further improve predictions made by onchocerciasis transmission models, demographic patterns in antibody responses to salivary antigens of Simulium damnosum s.l. are evaluated as a measure of blackfly exposure.

METHODOLOGY/PRINCIPAL FINDINGS

Recently developed IgG and IgM anti-saliva immunoassays for S. damnosum s.l. were applied to blood samples collected from residents in four onchocerciasis endemic villages in Ghana. Demographic patterns in antibody levels according to village, sex and age were explored by fitting generalized linear models. Antibody levels varied between villages but showed consistent patterns with age and sex. Both IgG and IgM responses declined with increasing age. IgG responses were generally lower in males than in females and exhibited a steeper decline in adult males than in adult females. No sex-specific difference was observed in IgM responses.

CONCLUSIONS/SIGNIFICANCE

The decline in age-specific antibody patterns suggested development of immunotolerance or desensitization to blackfly saliva antigen in response to persistent exposure. The variation between sexes, and between adults and youngsters may reflect differences in behaviour influencing cumulative exposure. These measures of antibody acquisition and decay could be incorporated into onchocerciasis transmission models towards informing onchocerciasis control, elimination, and surveillance.