Empirical exploration of whale optimisation algorithm for heart disease prediction.

Heart Diseases have the highest mortality worldwide, necessitating precise predictive models for early risk assessment. Much existing research has focused on improving model accuracy with single datasets, often neglecting the need for comprehensive evaluation metrics and utilization of different datasets in the same domain (heart disease). This research introduces a heart disease risk prediction approach by harnessing the whale optimization algorithm (WOA) for feature selection and implementing a comprehensive evaluation framework. The study leverages five distinct datasets, including the combined dataset comprising the Cleveland, Long Beach VA, Switzerland, and Hungarian heart disease datasets. The others are the Z-AlizadehSani, Framingham, South African, and Cleveland heart datasets. The WOA-guided feature selection identifies optimal features, subsequently integrated into ten classification models. Comprehensive model evaluation reveals significant improvements across critical performance metrics, including accuracy, precision, recall, F1 score, and the area under the receiver operating characteristic curve. These enhancements consistently outperform state-of-the-art methods using the same dataset, validating the effectiveness of our methodology. The comprehensive evaluation framework provides a robust assessment of the model's adaptability, underscoring the WOA's effectiveness in identifying optimal features in multiple datasets in the same domain.

Platelet-rich plasma for treating dry eye disease - A systematic review and meta-analysis.

PURPOSE: Dry eye disease has public health and economic significance. Platelet-rich plasma is rich in anti-inflammatory agents and growth factors, both beneficial for ocular surface repair. This study aimed to conduct a systematic review and meta-analysis to summarize the benefits of platelet-rich plasma for treating dry eye disease and its adverse effects. METHODS: Prospective comparative studies using platelet-rich plasma as monotherapy for dry eye disease were included for efficacy assessment. Before-after studies were included for adverse events assessment. Data sources included PubMed, Google Scholar, Web of Science, and Scopus. A systematic review and meta-analysis protocol was pre-registered on PROSPERO (CRD42022347982). PRISMA guidelines were followed. The National Health Institute (NIH) quality assessment tool for before-after studies, the Cochrane risk of bias tool (RoB2), and the methodological index for non-randomized studies were used to assess the risk of bias. Heterogeneity was assessed using the I2 statistic. RESULTS: 19 studies (10 comparative and 9 before-after) were included in the systematic review and meta-analysis. The occurrence rate of adverse effects was 2.6 % (95 % CI: 0.5 - 4.7). The pooled standardized mean difference (SMD) for dry eye symptoms was 0.81 (95 % CI: 0.25 - 1.37; I2 = 82 %; p < 0.00001; Z = 2.84, p = 0.004); tear quality was 0.44 (95 % CI: 0.06 - 0.81; I2 = 67 %; p = 0.003; Z = 2.26, p = 0.02); tear quantity was 0.45 (95 % CI: 0.03 - 0.88; I2 = 74 %; p = 0.0003; Z = 2.10, p = 0.04); and corneal staining 0.72 (95 % CI: 0.14 - 1.30; I2 = 85 %; p < 0.00001; Z = 2.43, p = 0.02). CONCLUSION: The current study shows that platelet-rich plasma is efficacious in managing dry eye disease, significantly reducing dry eye signs and symptoms. Such significant improvements could translate to improved quality of life.

Trace metal load of two urban wetlands with varied catchment activities in Ghana.

This study compared Lead (Pb), Chromium (Cr), Copper (Cu), Zinc (Zn), Mercury (Hg), Arsenic (As) and Cadmium (Cd) concentrations in sediment, water, and biota at Vaughan Dam which receives limited sewage effluent discharge from residential areas, and Korle Lagoon which receives industrial effluents, electronic waste, garages-spill oil and a host of others in addition to residential sewage effluent discharge. Samples were analyzed with Atomic Absorption Spectrometer. The results showed that concentrations of trace metals were generally higher in the sediment, water, and plants from the Korle Lagoon but only Cu in the sediment of Korle Lagoon showed a significantly high concentration. The similarities in the rank orders of the metal concentrations together with the dominance of Zn and Pb in most compartments of the wetlands indicated major differences did not exist in the contaminant input to the two wetlands except electronic waste recycling and disposal that resulted in significantly high copper concentrations in the sediment of Korle Lagoon. No evidence of biomagnification was determined along the food chains of the Vaughan Dam and the Korle Lagoon for all the metals studied.The Tilapia zilli from Vaughan Dam, the only biota that is regularly consumed from the wetlands, had Cr, Cu, Pb, Cd, Hg, and As concentrations above FAO/WHO permissible limits and therefore pose a health risk to consumers.

Association between Dyslipidemia and Meibomian Gland Dysfunction: A Systematic Review and Meta-Analysis.

PURPOSE: This study aimed to use meta-analysis to estimate the association between dyslipidemia and meibomian gland dysfunction. METHODS: The following databases were searched: PubMed, Google Scholar, and Scopus. Case-control and cohort studies assessing the association between dyslipidemia and meibomian gland dysfunction were included. The association was assessed using odds ratios. Heterogeneity between studies was assessed with the χ2 statistic and degree of inconsistency. The quality of studies was assessed using the Newcastle-Ottawa Scale. The systematic review was registered on PROSPERO (ID: CRD42022347982). RESULTS: The systematic review included three case-control and two cohort studies. The odds of hypercholesterolemia and hypertriglyceridemia in meibomian gland dysfunction were 5.45 (95% confidence interval [CI], 1.65 to 17.95) and 3.28 (95% CI, 1.25 to 8.62), respectively. The odds of elevated serum low-density lipoprotein and reduced high-density lipoprotein in meibomian gland dysfunction were 2.72 (95% CI, 1.24 to 5.98) and 1.15 (95% CI, 0.74 to 1.79), respectively. The current study's limitation is that the effects of sex, age, and meibomian gland dysfunction severity on the association between dyslipidemia and meibomian gland dysfunction were not assessed. CONCLUSIONS: The current study suggests a significant association between dyslipidemia and meibomian gland dysfunction. This finding suggests that meibomian gland dysfunction diagnosis may call for dyslipidemia screening.

Strabismus and amblyopia in Africa - a systematic review and meta-analysis.

The objective of this review was to estimate the prevalence of strabismus and amblyopia in Africa. A systematic online literature search was conducted for articles on strabismus and amblyopia in Africa. Meta-analysis was performed, using the Freeman-Tukey double arcsine transformation, to estimate the prevalence of strabismus and amblyopia in Africa. Subgroup analyses were conducted according to age, gender, study year, and type of amblyopia. Meta-regression was used to evaluate the influence of predetermined factors on the prevalence of amblyopia. 8 (1 population-based & 7 school-based) and 21 (3 population-based & 18 school-based) studies on strabismus and amblyopia with sample sizes of 22,355 and 46,841, respectively, were included in the review. Overall prevalence of strabismus in Africa was estimated to be 0.8% (95% CI: 0.4% - 1.4%); exotropia was 0.2% (95% CI: 0.1% - 0.5%) and esotropia was 0.5% (95% CI: 0.1% - 1.2%). Overall prevalence of amblyopia was estimated to be 0.6% (95% CI: 0.3% - 0.9%); refractive and strabismic amblyopia were 1.1% (95% CI: 0.2% - 2.5%) and 0.4% (95% CI: 0.2% - 0.6%), respectively. Prevalence estimate of amblyopia in males was 1.8% (95% CI: 0.7% - 3.3%) and in females was 1.3% (95% CI: 0.4% - 2.6%). There was a significant association between the prevalence of amblyopia and the type of amblyopia (p = .007) and the study year (p = .006). Although there appears to be a relatively low prevalence of strabismus and amblyopia in Africa, there is a dearth of well-designed population-based studies on strabismus and amblyopia in Africa, resulting in the lack of epidemiological information on strabismus and amblyopia within the general African population. Information about the prevalence of strabismus and amblyopia across Africa can inform policy making and design and implementation of public health intervention program.

Evaluation of organizational climate factors on tax administration enterprise resource planning (ERP) system.

Tax collection is an essential activity to boost the economy of all countries. Larger businesses and governments are increasingly relying on Enterprise Resource Planning (ERP) systems, which are designed to enhance the collection of revenues among other things. However, the implementation of an ERP system often affects the organizational climate by changing the manner businesses are conducted from the past both internally and externally. These changes have the tendency to impact the actions of workers throughout the transition process. Nevertheless, organization climate which is an essential variable to measure the success of ERPs is mostly underutilized. Thus in this study, we proposed an information system (IS) success model that integrates organizational climate variables namely, role clarity, teamwork and support, and, training and learning into the DeLone and McLean model to evaluate the success of a tax ERP system. The proposed model was based on a quantitative and a mixed-method case study (MM-CS). Data was gathered from a top company with many branches in Ghana through interviews, observation, focus groups, and questionnaires. Partial least squares structural equation modeling was used to examine the 555 data collected from the questionnaire. The result of the study shows that the organizational climate variables (training & learning, teamwork & support, and role clarity) were statistically significant in determining the success of a tax ERP system. Training & learning and teamwork & support also had a positive impact on service quality, user satisfaction, and individual impact.

Robust facial expression recognition system in higher poses.

Facial expression recognition (FER) has numerous applications in computer security, neuroscience, psychology, and engineering. Owing to its non-intrusiveness, it is considered a useful technology for combating crime. However, FER is plagued with several challenges, the most serious of which is its poor prediction accuracy in severe head poses. The aim of this study, therefore, is to improve the recognition accuracy in severe head poses by proposing a robust 3D head-tracking algorithm based on an ellipsoidal model, advanced ensemble of AdaBoost, and saturated vector machine (SVM). The FER features are tracked from one frame to the next using the ellipsoidal tracking model, and the visible expressive facial key points are extracted using Gabor filters. The ensemble algorithm (Ada-AdaSVM) is then used for feature selection and classification. The proposed technique is evaluated using the Bosphorus, BU-3DFE, MMI, CK + , and BP4D-Spontaneous facial expression databases. The overall performance is outstanding.

Identification of a fall armyworm (Spodoptera frugiperda)-specific gene and development of a rapid and sensitive loop-mediated isothermal amplification assay.

The fall armyworm [FAW, Spodoptera frugiperda (J E Smith)], a moth native to America, has spread throughout the world since it was first discovered in Africa in 2016. The FAW is a polyphagous migratory pest that can travel over long distances using seasonal winds or typhoons because of its excellent flying ability, causing serious damage to many crops. For effective FAW control, accurate species identification is essential at the beginning of the invasion. In this study, the FAW-specific gene Sf00067 was discovered by performing bioinformatics to develop a fast and accurate tool for the species-specific diagnosis of this pest. An Sf00067 loop-mediated isothermal amplification (LAMP) assay was developed, and optimal conditions were established. The Sf00067 6 primer LAMP (Sf6p-LAMP) assay established in this study was able to diagnose various genotype-based strains of FAW captured in Korea and FAWs collected from Benin, Africa. Our FAW diagnostic protocol can be completed within 30 min, from the process of extracting genomic DNA from an egg or a 1st instar larva to species determination.

PREVALENCE OF MEIBOMIAN GLAND DYSFUNCTION IN AFRICA: A SYSTEMATIC REVIEW AND META-ANALYSIS OF OBSERVATIONAL STUDIES.

PURPOSE: To review and summarize information on meibomian gland dysfunction (MGD) epidemiology in Africa. METHODS: A systematic search of online databases was conducted for literature/studies on MGD in Africa. Meta-analysis was conducted to estimate the prevalence of MGD in Africa. Meta-regression was used to explore sources of heterogeneity. RESULTS: Twelve studies conducted in five countries were included in the review. All studies were hospital-based studies. Nine studies were included in the meta-analysis; the total sample size was 4963 and participants' age range was 17-96 years. The overall prevalence estimate of MGD in Africa was 45.9% (95% CI: 27.6-64.1%). Prevalence of MGD among males and females were each pooled from three studies and in urban and rural setting from 6 and 3 studies, respectively. Prevalence of MGD among males and females were 56.0% (95% CI: 22.4-89.5%) and 58.9% (95% CI: 28.5-89.4%) respectively; in urban and rural settings were 42.8% (95% CI: 21.1-64.5%) and 65.7% (95% CI: 25.7-95.7%), respectively. There was no association of MGD with sex (p = .872) and with study setting (p = .231). CONCLUSION: There is a paucity of evidence on MGD prevalence in Africa, emphasizing the need for epidemiological studies to enhance our understanding of region-specific differences in MGD in Africa. The pooled estimate from hospital-based studies, however, suggests a substantial MGD burden in Africa. Epidemiological studies are needed to assess if this translates to a high disease burden within the general African population.

Prevalence and associated risk factors of symptomatic dry eye in Ghana: A cross-sectional population-based study.

PURPOSE: This study sought to estimate the prevalence and associated risk factors of symptomatic dry eye in the general non-clinical Ghanaian population. METHODS: This was a cross-sectional population-based study conducted from November 2019 to February 2020. A stratified, multistage, random sampling technique was used to select participants aged 18 years and above from the capital cities of eight administrative regions in Ghana. Symptomatic dry eye was assessed using the Ocular Surface Disease Index questionnaire (OSDI). A study specific structured questionnaire was administered to collect information on participants' demographics and self-reported risk factors of dry eye disease such as smoking, diabetes, hypertension, arthritis, ocular allergies, pregnancy, contact lens wear, use of topical glaucoma medication and multivitamin supplement. Multiple linear regression analysis was used to explore associations between symptomatic dry eye and participant characteristics. A p-value of 0.05 was considered statistically significant. RESULTS: A total of 1316 individuals participated in the study [mean (SD) age 37.0 (15.72) years; range 18-90 years; 50.2 % males]. The prevalence of symptomatic dry eye was 69.3 % [95 % CI: 66.7 % - 71.7 %; mean (SD) OSDI score of 26.97 (21.52)]: 19.8 %, 16.6 % and 32.9 % mild, moderate and severe symptoms respectively. The most common ocular symptom was sensitivity to light (experienced at least some of the time), reported by 67.1 % of participants; most affected vision-related activity was reading (49.3 %); most common environmental trigger of dry eye symptoms was windy conditions (61.3 %). There was a significant positive association between symptomatic dry eye and age (p < .0001), female sex (p = .026), arthritis (p = .031), ocular surface allergy (p = .036) and regional zone (p = .043). CONCLUSION: There is a high prevalence of dry eye symptoms in Ghana. This represents a high dry eye disease burden and a significant public health problem that needs immediate attention.

Computer-Aided Diagnostics of Heart Disease Risk Prediction Using Boosting Support Vector Machine.

Heart diseases are a leading cause of death worldwide, and they have sparked a lot of interest in the scientific community. Because of the high number of impulsive deaths associated with it, early detection is critical. This study proposes a boosting Support Vector Machine (SVM) technique as the backbone of computer-aided diagnostic tools for more accurately forecasting heart disease risk levels. The datasets which contain 13 attributes such as gender, age, blood pressure, and chest pain are taken from the Cleveland clinic. In total, there were 303 records with 6 tuples having missing values. To clean the data, we deleted the 6 missing records through the listwise technique. The size of data, and the fact that it is a purely random subset, made this approach have no significant effect for the experiment because there were no biases. Salient features are selected using the boosting technique to speed up and improve accuracies. Using the train/test split approach, the data is then partitioned into training and testing. SVM is then used to train and test the data. The C parameter is set at 0.05 and the linear kernel function is used. Logistic regression, Nave Bayes, decision trees, Multilayer Perceptron, and random forest were used to compare the results. The proposed boosting SVM performed exceptionally well, making it a better tool than the existing techniques.

The effect of vinegar and drying (Solar and Open Sun) on the microbiological quality of ginger (ZINGIBER OFFICINALE ROSCOE) rhizomes.

This study evaluated the influence of 10% vinegar and solar drying using two solar dryers and open-sun drying on the microbiological quality of ginger (Zingiber officinale Roscoe) rhizome. The rhizomes were analyzed for bacterial, mold, and Salmonella populations in the raw state, which were water-washed and soaked in 10% vinegar, and in dried form. The fungal population was isolated and identified. Fresh and dried ginger rhizome contained both bacterial and fungal population in the range of 3.0 x 102 ± 1.14 x 102 to 2,180 x 109 ± 70.7 x 109 CFU/g. The stainless steel solar dryer had fewer fungal loads among the drying methods. Aspergillus and Penicillium species of mycotoxin-producing potential were identified. The 10% vinegar as pretreatment showed no significant difference (p ≤ .05) in the bacterial population reduction but in the fungal population reduction. Growth of fungi in fresh and dried ginger extracts was lower compared with growth in Potato Dextrose Broth.

Career aspirations and factors influencing career choices of optometry students in Ghana.

Optometry students in clinical years are usually faced with the challenges of making a career choice in or outside optometry. This cross sectional study was conducted to investigate the career aspirations of optometry students in Ghana. All students in their fourth to sixth year who consented to participate in the study responded to a questionnaire which explored: demographic characteristics, career aspirations, and factors influencing their choices. Descriptive statistics was used to present data as frequencies, proportions and percentages. Chi-square test and logistic regression analysis were used to evaluate relationships between variables. Two hundred and nine students from the two optometry training institutions in Ghana; Kwame Nkrumah University of Science and Technology (49.8%) and University of Cape Coast (51.2%) responded to the questionnaire. The mean (SD) age of students was 23.6 (1.9) years (males = 65.6%). On seeking admission into the university, optometry (65.6%) and human biology/medicine (28.2%) were the leading first choice programmes among participants. Participants largely aspire to be in clinical practice (64.6%) or Academia/Research (28.2%). The major factors which influenced career choices were interest in career field (64.1%) and potential good income (38.3%). Females were twice more likely to practice optometry and pursue an interest in paediatric optometry than males. Institution of study (p = .028) and information on career opportunities (p = .018) were significant predictors of students' decision to pursue a career in academia/research. Optometry students in Ghana largely aspire to be in clinical practice, a finding which is useful for optometry training institutions and relevant stakeholders in developing the optometry programme and projecting its future in Ghana.

Insecticidal activities of cinnamic acid esters isolated from Ocimum gratissimum L. and Vitellaria paradoxa Gaertn leaves against Tribolium castaneum Hebst (Coleoptera: Tenebrionidae).

BACKGROUND: Pest management using botanicals has been widely practiced in sub-Saharan Africa and other parts of the world in recent times. The natural compounds present in these botanicals are known to be responsible for the protection they offer against insect pests. Some of these compounds may act as single compounds to produce an effect or they may be synergistically effective. In the present study using a bioassay guided approach, two cinnamic acid derivatives, methyl cinnamate and sitosterol cinnamate, were isolated from the leaves of Ocimum gratissimum and Vitellaria paradoxa, respectively. RESULTS: The two cinnamic acid derivatives were found to show higher levels of insecticidal, larvicidal and larval growth inhibition activities against Tribolium castaneum. The LC50 of methyl cinnamate was determined to be 26.92 mg mL-1 (95% CL: 1.18.66-38.84 mg mL-1 ; slope ± SE: 2.84 ± 0.81) for the adult 8.31 mg mL-1 (95% CL: 2.39-28.83 mg mL-1 ; slope ± SE: 0.66 ± 0.28) for the larvae while the LC50 of sitosterol cinnamate was determined to be 6.92 mg mL-1 (95% CL: 3.97-12.06 mg mL-1 ; slope ± SE: 1.59 ± 0.12) the adult and 3.91 mg mL-1 (95% CL: 2.21-6.93 mg mL-1 ; slope ± SE: 1.52 ± 0.13) for the larvae. CONCLUSION: Generally, the susceptibility of adult T. castaneum to these cinnamic acid esters can be directly associated with the concentration as well as time of exposure to the compounds. The isolated compounds support the use of O. gratissimum and V. paradoxa as important botanicals for the management of storage pests. © 2019 Society of Chemical Industry.

Native SAG1 in Toxoplasma gondii lysates is superior to recombinant SAG1 for serodiagnosis of T. gondii infections in chickens.

Toxoplasma gondii can infect almost all mammals and birds, including chickens. The aim of this study was to identify an appropriate immunogenic antigen for serodiagnosis of T. gondii infections in chickens. We examined serum samples from chickens that were intravenously or intraperitoneally infected with 106-108 tachyzoites of T. gondii strains PLK, RH, CTG, ME49 or TgCatJpGi1/TaJ using enzyme-linked immunosorbent assays (ELISAs), latex agglutination tests (LATs) and western blotting. Regardless of parasite strain or infection dose and route, the commercial LAT was positive for almost all sera collected 1 week post-infection. However, at 2 weeks post-infection, LATs were negative in the same birds. ELISAs using the Escherichia coli-produced recombinant T. gondii antigens SAG1 and GRA7 showed strong signals at 1-2 weeks post infection, but thereafter diminished for the majority of serum samples. In contrast, western blotting against crude tachyzoite antigens showed a persistent band up to 4 weeks post-infection. Sera from these chickens reacted much more strongly with SAG1 from crude tachyzoite antigens than with recombinant SAG1. Even in experimentally-infected birds whose parasite burdens in tissue were undetectable, sera still reacted with native SAG1. We tested sera from free-range chickens on a small farm in Ghana, Africa, using western blotting and found that the serum of one bird reacted with a single band of approximately 27 kDa, the putative molecular weight of SAG1. Thus we conclude that native SAG1, but not E. coli-produced recombinant SAG1, is suitable for serodiagnosis of T. gondii infections in chickens.

Weight loss and mortality risk in patients with different adiposity at diagnosis of type 2 diabetes: a longitudinal cohort study.

BACKGROUND: Undiagnosed comorbid diseases that independently lead to weight loss before type 2 diabetes mellitus (T2DM) diagnosis could explain the observed increased mortality risk in T2DM patients with normal weight. OBJECTIVES: To evaluate the impact of weight change patterns before the diagnosis of T2DM on the association between body mass index (BMI) at diagnosis and mortality risk. METHODS: This was a longitudinal cohort study using 145,058 patients from UK primary care, with newly diagnosed T2DM from January 2000. Patients aged 18-70, without established disease history at diagnosis (defined as the presence of cardiovascular diseases, cancer, and renal diseases on or before diagnosis) were followed up to 2014. Longitudinal 6-monthly measures of bodyweight three years before (used to define groups of patients who lost bodyweight or not before diagnosis) and 2 years after diagnosis were obtained. The main outcome was all-cause mortality. RESULTS: At diagnosis, mean (SD) age was 52 (12) years, 56% were male, 52% were current or ex-smokers, mean BMI was 33 kg/m2, and 66% were obese. Normal weight and overweight patients experienced a small but significant reduction in body weight 6 months before diagnosis. Among all categories of obese patients, consistently increasing body weight was observed within the same time window. Among patients who did not lose body weight pre-diagnosis (n = 117,469), compared with the grade 1 obese, normal weight patients had 35% (95% CI of HR: 1.17, 1.55) significantly higher adjusted mortality risk. However, among patients experiencing weight loss before diagnosis (n = 27,589), BMI at diagnosis was not associated with mortality risk (all p > 0.05). CONCLUSIONS: Weight loss before the diagnosis of T2DM was not associated with the observed increased mortality risk in normal weight patients with T2DM. This emphasises the importance of addressing risk factors post diagnosis for excess mortality in this group.

To coil or not to coil: application practices, perception and efficacy of mosquito coils in a malaria-endemic community in Ghana.

Although evidence of mosquito coils' impact on disease epidemiology is limited, they are popularized as mosquito-borne disease prevention devices. Their usage affects the environment, human and mosquito health. This study investigated the perception, usage pattern and efficacy of coils in a predominantly poor malaria-endemic Ghanaian peri-urban area. Information on protection methods, perception and usage pattern was garnered using questionnaires. The efficacy of commonly used coils in the area was then assessed on the malaria vector, Anopheles gambiae, in a glass chamber. Sole or co-application of mosquito control methods and risky usage practices were reported. Coils were deemed harmful to humans and mosquitoes, and their perceived effectiveness varied, with several factors influencing their purchase. High d-allethrin concentration coils induced quicker mosquito knockdown; however, mortality was less than 85%. The coil usage pattern compromises users' health and can enhance mosquito tolerance to d-allethrin. The coils were ineffective against the vector, outlining a dichotomy between the users' perception of efficacy and the observed efficacy. Hence, the usage of other safer and more effective vector control methods should be encouraged to protect households.

Does Increasing Treatment Frequency Address Suboptimal Responses to Ivermectin for the Control and Elimination of River Blindness?

BACKGROUND: Several African countries have adopted a biannual ivermectin distribution strategy in some foci to control and eliminate onchocerciasis. In 2010, the Ghana Health Service started biannual distribution to combat transmission hotspots and suboptimal responses to treatment. We assessed the epidemiological impact of the first 3 years of this strategy and quantified responses to ivermectin over 2 consecutive rounds of treatment in 10 sentinel communities. METHODS: We evaluated Onchocerca volvulus community microfilarial intensity and prevalence in persons aged ≥20 years before the first, second, and fifth (or sixth) biannual treatment rounds using skin snip data from 956 participants. We used longitudinal regression modeling to estimate rates of microfilarial repopulation of the skin in a cohort of 217 participants who were followed up over the first 2 rounds of biannual treatment. RESULTS: Biannual treatment has had a positive impact, with substantial reductions in infection intensity after 4 or 5 rounds in most communities. We identified 3 communities-all having been previously recognized as responding suboptimally to ivermectin-with statistically significantly high microfilarial repopulation rates. We did not find any clear association between microfilarial repopulation rate and the number of years of prior intervention, coverage, or the community level of infection. CONCLUSIONS: The strategy of biannual ivermectin treatment in Ghana has reduced O. volvulus microfilarial intensity and prevalence, but suboptimal responses to treatment remain evident in a number of previously and consistently implicated communities. Whether increasing the frequency of treatment will be sufficient to meet the World Health Organization's 2020 elimination goals remains uncertain.