Detecting and staging podoconiosis cases in North West Cameroon: positive predictive value of clinical screening of patients by community health workers and researchers

Epidemiology of podoconiosis in sub-Saharan Africa: A systematic review and meta-analysis

Objective

Podoconiosis, one of the neglected tropical diseases (NTDs), affects barefoot people in impoverished regions and contributes to poverty by having negative impacts on economic output, education, and disability. People who have the disease waste nearly half of all of their productive workdays. There is limited evidence available on prevalence of podoconiosis in sub-Saharan Africa (SSA). Therefore, the aim of this research was to determine the pooled prevalence of podoconiosis in the SSA over the last 10 years.

Methods

Studies were retrieved from PubMed, Embase, Web of Science, Scopus, Google Scholar, and Google by using a combination of search terms with Boolean operators. All authors independently assessed each study's quality using the modified Newcastle-Ottawa Scale for cross-sectional studies. STATA Version 14 was used to conduct the statistical analysis. The random-effect approach of meta-analysis was used. To test for heterogeneity, I-Squared (I2) statistics were employed and sensitivity analysis with a leave-one-out was done.

Result

In this systematic review and meta-analysis, a total of 16 publications with 2,195,722 individuals were included. The pooled prevalence of podoconiosis was 2.66 (95% confidence interval (CI): 2.24, 3.10) with heterogeneity index (I2) of 99.9%. Walking barefoot adjusted odd ratio (AOR) 5.35 (95% CI: 1.65, 9.05), p = 0.001, not washing feet with soap and water regularly AOR 2.8 (95% CI: 1.16, 4.44, p = 0.001), and an increased age AOR 2.23 (95% CI: 1.25, 5.58) were factors significantly associated with the prevalence of podoconiosis.

Conclusion

This study revealed that pooled prevalence of podoconiosis was considerable in SSA. Age, being barefoot, and failing to wash one's feet with soap and water have been identified to be factors that were significantly associated with the prevalence of podoconiosis. Therefore, creating awareness on shoe wearing and providing shoes in communication with supporting organizations in podoconiosis prevalent areas, and early diagnosis based on family history are needed for the prevention of podoconiosis.

Tropical leg lymphedema caused by podoconiosis is associated with increased colonisation by anaerobic bacteria

The non-filarial and non-communicable disease podoconiosis affects around 4 million people and is characterized by severe leg lymphedema accompanied with painful intermittent acute inflammatory episodes, called acute dermatolymphangioadenitis (ADLA) attacks. Risk factors have been associated with the disease but the mechanisms of pathophysiology remain uncertain. Lymphedema can lead to skin lesions, which can serve as entry points for bacteria that may cause ADLA attacks leading to progression of the lymphedema. However, the microbiome of the skin of affected legs from podoconiosis individuals remains unclear. Thus, we analysed the skin microbiome of podoconiosis legs using next generation sequencing. We revealed a positive correlation between increasing lymphedema severity and non-commensal anaerobic bacteria, especially Anaerococcus provencensis, as well as a negative correlation with the presence of Corynebacterium, a constituent of normal skin flora. Disease symptoms were generally linked to higher microbial diversity and richness, which deviated from the normal composition of the skin. These findings show an association of distinct bacterial taxa with lymphedema stages, highlighting the important role of bacteria for the pathogenesis of podoconiosis and might enable a selection of better treatment regimens to manage ADLA attacks and disease progression.

Phenotypical characterization, and antibiotics susceptibility patterns of skin bacteria found in podoconiosis patients in the North West Region of Cameroon

BACKGROUND

Podoconiosis, a non-infectious disease originating from long-term exposure of bare feet to irritant red clay soil is a lifelong, disabling disease with no specific diagnostic tool, classified into 5 stages based on the severity of leg swelling (lymphoedema). Secondary bacterial infections have been suggested to cause acute dermatolymphangioadenitis (ADLA) attacks and drive disease progression. Although the North West Region of Cameroon has a proven history of podoconiosis endemicity, the bacterial composition of lymphoedema due to this condition has not been studied. Thus, this study investigated the leg bacterial diversity of patients who suffered from the lymphoedema and their susceptibility pattern to selected antibiotics.

METHODS

A cross-sectional study was carried out in which podoconiosis affected and non-lymphoedema individuals living in the same community were purposively selected. Samples were collected by swabbing the skin between the toes and around the anklebone, then cultured and sub-cultured on nutrient agar to obtain pure isolates. The cultured isolates were then morphologically and biochemically classified using microscopy and analytic profile index test kits, respectively. The disk diffusion technique was used to determine antibiotic susceptibility.

RESULTS

Thirty-three participants were recruited, and 249 bacterial isolates were characterized into 29 genera, 60 species; with 30 (50%) being gram positive rods, 19 (31.7%) gram positive cocci, and 11 (18.3%) gram negative rods. Thirteen gram positive rods, fifteen gram positive cocci, and eight gram negative rods of bacterial species were found only in podoconiosis individuals among which Cellulomonas spp / Microbacterium spp. (2.8%), Staphylococcus lentus (3.3%), and Burkholderia cepacia (4.0%) dominated. 90% (90%) of the bacterial isolates were sensitive to doxycycline, whereas ampicillin had a high level of intermediate resistance, and penicillin G had the greatest resistant profile.

CONCLUSION

Our findings show that 94 (37.8%) out of 249 described bacterial isolates were exclusively found in the legs of podoconiosis individuals, and their susceptibility pattern to antibiotics was similar to that of others.

Developing and validating a clinical algorithm for the diagnosis of podoconiosis

BACKGROUND

Difficulties in reliably diagnosing podoconiosis have severely limited the scale-up and uptake of the World Health Organization-recommended morbidity management and disability prevention interventions for affected people. We aimed to identify a set of clinical features that, combined into an algorithm, allow for diagnosis of podoconiosis.

METHODS

We identified 372 people with lymphoedema and administered a structured questionnaire on signs and symptoms associated with podoconiosis and other potential causes of lymphoedema in northern Ethiopia. All individuals were tested for Wuchereria bancrofti-specific immunoglobulin G4 in the field using Wb123.

RESULTS

Based on expert diagnosis, 344 (92.5%) of the 372 participants had podoconiosis. The rest had lymphoedema due to other aetiologies. The best-performing set of symptoms and signs was the presence of moss on the lower legs and a family history of leg swelling, plus the absence of current or previous leprosy, plus the absence of swelling in the groin, plus the absence of chronic illness (such as diabetes mellitus or heart or kidney diseases). The overall sensitivity of the algorithm was 91% (95% confidence interval [CI] 87.6 to 94.4) and specificity was 95% (95% CI 85.45 to 100).

CONCLUSIONS

We developed a clinical algorithm of clinical history and physical examination that could be used in areas suspected or endemic for podoconiosis. Use of this algorithm should enable earlier identification of podoconiosis cases and scale-up of interventions.

Linking soils and human health: geospatial analysis of ground-sampled soil data in relation to community-level podoconiosis data in North West Cameroon

Background

Podoconiosis is a form of leg swelling, which arises when individuals are exposed over time to red clay soil formed from alkaline volcanic rock. The exact causal agent of the disease is unknown. This study investigates associations between podoconiosis disease data and ground-sampled soil data from North West Cameroon.

Methods

The mineralogy and elemental concentrations were measured in the soil samples and the data were spatially interpolated. Mean soil values were calculated from a 3 km buffer region around the prevalence data points to perform statistical analysis. Analysis included Spearman's rho correlation, binary logistic regression and principal component analysis (PCA).

Results

Six elements, barium, beryllium, potassium, rubidium, strontium and thallium, as well as two minerals, potassium feldspar and quartz, were identified as statistically related to podoconiosis. PCA did not show distinct separation between the spatial locations with or without recorded cases of podoconiosis, indicating that other factors such as shoe-wearing behaviour and genetics may significantly influence podoconiosis occurrence and prevalence in North West Cameroon.

Conclusion

Several soil variables were statistically significantly related to podoconiosis. To further the current study, future investigations will look at the inflammatory pathway response of cells after exposure to these variables.

Podoconiosis in Rwanda: Knowledge, attitudes and practices among health professionals and environmental officers

Background

Podoconiosis is a neglected tropical disease commonly found in volcanic regions, where soil is rich in silica. It usually manifests as bilateral lower limb edema. The majority of people affected by podoconiosis are farmers who do not wear shoes. The condition was recently documented in all 30 districts in Rwanda but knowledge, attitudes and practices (KAP) of Rwandan health professionals and environmental officers towards podoconiosis are unknown.

Methodology/Findings

The objective of this study was to assess the knowledge, attitudes and practices (KAP) of Rwandan health providers and environmental officers towards podoconiosis in order to improve patient healthcare experiences and health outcomes, and to reduce stigma against affected individuals. To achieve this goal, we administered a KAP assessment to physicians (N = 13), nurses/midwives (N = 59), community health workers (N = 226), and environmental officers (N = 38) in the third highest podoconiosis prevalence district in Rwanda (Musanze).

All 336 respondents had heard of podoconiosis, but 147 (44%) respondents correctly identified soil as the only direct cause of podoconiosis. The awareness of signs and symptoms and risk groups was lower than any other category (31.5% and 47.5%, respectively). The overall attitude toward podoconiosis was positive (86.1%), with CHWs least likely to harbor negative beliefs against podoconiosis patients. One particular area where most respondents (76%) expressed negative attitude was that they saw people with podoconiosis as a threat to their own health and their family’s health. Prescription of antibiotics and use of ointments/soap to manage wounds was low (5% and 32.2%, respectively), in part due to supply shortages at health facilities.

Conclusions

This study identified clear gaps in health provider knowledge and practices that affect patient care for those with podoconiosis. Improved access to essential medicines at health facilities and podoconiosis-focused training sessions for practicing health providers are necessary to minimize the burden and stigma of affected individuals.

Podoconiosis is a foot disease that progressively affects genetically susceptible people who do not wear shoes in volcanic soil. This disease causes disability, stigma, and impinges on people’s economic productivity. In Rwanda, it is estimated that 6429 people live with podoconiosis, but health services for these particular patients are almost nonexistent. We evaluated knowledge, attitudes and practice among 298 health professionals and 38 environmental officers and found that only 44% of all respondents knew that soil is the only direct cause of podoconiosis. Few health professionals (6%) reported having treated a podoconiosis patient and most health professionals (79%) identified shortages of critical drugs and supplies as an important barrier to providing treatment. Three quarters of environmental officers (74%) did not know that farmers are the people most vulnerable to this condition. The poor knowledge of all respondents toward podoconiosis and the lack of medical supplies suggest that podoconiosis patients likely receive substandard medical care and receive little credible information on prevention. We recommend a multi-sectoral approach to training, as well as the engagement of governments and the World Health Organization, to avail medications and treatment materials in the community.

Mapping of lymphatic filariasis in loiasis areas: A new strategy shows no evidence for Wuchereria bancrofti endemicity in Cameroon

BACKGROUND

Mapping of lymphatic filariasis (LF) caused by Wuchereria bancrofti largely relies on the detection of circulating antigen using ICT cards. Several studies have recently shown that this test can be cross-reactive with sera of subjects heavily infected with Loa loa and thus mapping results in loiasis endemic areas may be inaccurate.

METHODOLOGY/PRINCIPAL FINDINGS

In order to develop an LF mapping strategy for areas with high loiasis prevalence, we collected day blood samples from 5,001 subjects residing in 50 villages that make up 6 health districts throughout Cameroon. Antigen testing using Filarial Test Strip (FTS, a novel platform that uses the same reagents as ICT) revealed an overall positivity rate of 1.1% and L. loa microfilaria (Mf) rates of up to 46%. Among the subjects with 0 to 8,000 Mf/ml in day blood, only 0.4% were FTS positive, while 22.2% of subjects with >8,000 Mf/ml were FTS positive. A Mf density of >8,200 Mf/ml was determined as the cut point at which positive FTS results should be excluded from the analysis. No FTS positive samples were also positive for W. bancrofti antibodies as measured by two different point of care tests that use the Wb123 antigen not found in L. loa. Night blood examination of the FTS positive subjects showed a high prevalence of L. loa Mf with densities up to 12,710 Mf/ml. No W. bancrofti Mf were identified, as confirmed by qPCR. Our results show that high loads of L. loa Mf in day blood are a reliable indicator of FTS positivity, and Wb123 rapid test proved to be relatively specific.

CONCLUSIONS/SIGNIFICANCE

Our study provides a simple day blood-based algorithm for LF mapping in loiasis areas. The results indicate that many districts that were formerly classified as endemic for LF in Cameroon are non-endemic and do not require mass drug administration for elimination of LF.

Study of lymphoedema of non-filarial origin in the northwest region of Cameroon: spatial distribution, profiling of cases and socio-economic aspects of podoconiosis

Background

Although podoconiosis is endemic in Cameroon, little is known about its epidemiology and spatial distribution.

Methods

This cross-sectional, population-based study enrolled all adults (≥15 y) residing in the districts of the northwest region of Cameroon for 10 or more years. Participants were interviewed and had a physical examination. The study outcomes were prevalence estimates of lymphoedema and podoconiosis. House-to-house screening was conducted by Community Health Implementers (CHIs). CHIs registered all individuals with lymphoedema and collected additional individual and household-related information. A panel of experts re-examined and validated all lymphoedema cases registered by CHIs.

Results

Of the 439 781 individuals registered, 214 195 were adults (≥15 y old) and had lived in the districts of the region for more than 10 y. A total of 2143 lymphoedema cases were identified by CHIs, giving a prevalence of lymphoedema of 1.0% (2143/214 195; 95% CI, 0.96-1.04). After review by experts, podoconiosis prevalence in the study area was 0.48% (1049/214 195; 95% CI, 0.46-0.52). The prevalence of podoconiosis varied by health district, from 0.16% in Oku to 1.92% in Bafut (p<0.05). A total of 374 patients were recruited by stratified random sampling from the validated CHIs' register to assess the clinical features and socio-economic aspects of the disease. Patients reportedly were said to have first noticed swelling at an average age of 41.9±19.1 (range: 6-90 y). Most patients (86.1%; 315/366) complained of their legs suddenly becoming hot, red and painful. The majority (96.5%; 361/374) of the interviewees said they had worn shoes occasionally at some point in their life. The reported mean age at first shoe wearing was 14.2±10.1 (±SD,range 1-77 y). A high proportion (82.8%; 309/374) of the participants wore shoes at the time of interview. Of those wearing shoes, only 21.7% (67/309) were wearing protective shoes.

Conclusion

This study provides an insight into the geographical distribution and epidemiology of podoconiosis in the North West region of Cameroon, yet management is limited. Evidence-informed targeted interventions are needed to manage people with lymphoedema.

Community based cross sectional study of podoconiosis and associated factors in Dano district, Central Ethiopia

Background

Podoconiosis, affects lower limb, is an entirely preventable non-communicable tropical disease common in low income countries. Globally it is estimated that there are 4 million peoples with podoconiosis and nationally it is estimated that there are 1.56 million cases of podoconiosis. Even though nationwide mapping has been conducted including the current district under investigation, there are no studies conducted to identify factors associated with podoconiosis in the district. Hence, this study was aimed to determine the prevalence of podoconiosis and associated factors in the west Shewa of Dano district community.

Method

A community based cross sectional study was conducted from March 1 to 26, 2018. Seven kebeles out of the total of twenty-three kebeles found in the district were selected randomly. The total sample size was allocated by probability proportional to size to each kebele based on the number of households they had. Then, systematic random sampling was employed to select 652 study participants from the seven kebeles. Data was collected using interviewer administered structured questionnaire and observation. In addition, a blood sample was collected from the study subjects who had leg swelling for ruling out lymphedema due to lymphatic filarasis by using Immunochromatographic test card. Podoconiosis case was defined as bilateral but asymmetric swelling which develop first in the foot often confined to the lower leg and negative result for immune-chromatographic test (ICT card). The prevalence of podoconiosis was determined and multiple logistic regression model was fitted using SPSS version 23 to identify factors associated with podoconiosis.

Result

The prevalence of podoconiosis in Dano district was found to be 6.3% (95%CI: 5.8, 6.8). Age at first shoe wearing (AOR = 1.08,95% CI = 1.06–1.11), washing practice of feet by water only (AOR = 3.68, 95% CI = 1.47–9.24) and not wearing shoe daily (AOR = 9.32, 95% CI = 4.27–20.4) were found to be significantly associated with increased odds of podoconiosis.

Conclusion

This study revealed that there was significant burden of podoconiosis in the study area. Age at first shoe wearing, washing practice and frequency of shoe wearing were associated with the development of podoconiosis disease. Modalities to enhance the shoe wearing behaviour of the communities should be planned by high level decision makers working in the area of Health. Moreover, collaboration between local government and non-government stakeholders, and integration with existing programs addressing foot hygiene which involves washing feet with soap and water needs to be addressed.

Podoconiosis (endemic non-filarial elephantiasis) is one of a disabling and stigmatizing neglected tropical disease (NTD) which affects the lower limb found mostly in low income countries. Even though there were mostly prevalence studies and disease mapping, there was no report, especially on factors associated with the disease, from the study area. Hence, community based cross sectional study was conducted to determine its prevalence and factors associated with it in the west Shewa Zone of Dano district community. Data were collected from a total of 652 randomly selected peoples using interviewer administered structured questionnaire and observation. In addition, a blood sample was collected from the study subjects who had leg swelling for ruling out lymphedema due to lymphatic filarasis by using Immunochromatographic test card. Podoconiosis case was defined as bilateral but asymmetric swelling which develop first in the foot often confined to the lower leg and negative result for immune-chromatographic test (ICT card). Accordingly, the prevalence of podoconiosis in the district was found to be 6.3%. Age at first shoe wearing, washing practice of feet by water only and not wearing shoe daily were found to be the risk factors for the development of podoconiosis. Hence, this study revealed that there was significant burden of the disease in the study area. Thus, collaboration between local government and non-government stakeholders, and integration with existing programs addressing foot hygiene which involves washing feet with soap and water needs to be addressed.

Predicted distribution and burden of podoconiosis in Cameroon

INTRODUCTION

Understanding the number of cases of podoconiosis, its geographical distribution and the population at risk are crucial to estimating the burden of this disease in endemic countries. We assessed each of these using nationwide data on podoconiosis prevalence in Cameroon.

METHODS

We analysed data arising from two cross-sectional surveys in Cameroon. The dataset was combined with a suite of environmental and climate data and analysed within a robust statistical framework, which included machine learning-based approaches and geostatistical modelling. The environmental limits, spatial variation of predicted prevalence, population at risk and number of cases of podoconiosis were each estimated.

RESULTS

A total of 214 729 records of individuals screened for podoconiosis were gathered from 748 communities in all 10 regions of Cameroon. Of these screened individuals, 882 (0.41%; 95% CI 0.38 to 0.44) were living with podoconiosis. High environmental suitability for podoconiosis was predicted in three regions of Cameroon (Adamawa, North West and North). The national population living in areas environmentally suitable for podoconiosis was estimated at 5.2 (95% CI 4.7 to 5.8) million, which corresponds to 22.3% of Cameroon's population in 2015. Countrywide, in 2015, the number of adults estimated to be suffering from podoconiosis was 41 556 (95% CI, 1170 to 240 993). Four regions (Central, Littoral, North and North West) contributed 61.2% of the cases.

CONCLUSION

In Cameroon, podoconiosis is more widely distributed geographically than was initially expected. The number of cases and the population at risk are considerable. Expanding morbidity management and follow-up of cases is of utmost necessity. Promotion of footwear use and regular foot hygiene should be at the forefront of any intervention plan.

Pragmatism in practice: lessons learned during screening and enrollment for a randomised controlled trial in rural northern Ethiopia

Background

We use the example of the Gojjam Lymphoedema Best Practice Trial (GoLBeT), a pragmatic trial in a remote rural setting in northern Ethiopia, to extract lessons relevant to other investigators balancing the demands of practicality and community acceptability with internal and external validity in clinical trials.

Methods

We explain in detail the preparation for the trial, its setting in northern Ethiopia, the identification and selection of patients (inclusion and exclusion criterion, identifying and screening of patients at home, enrollment of patients at the health centres and health posts), and randomisation.

Results

We describe the challenges met, together with strategies employed to overcome them.

Conclusions

Examples given in the previous section are contextualised and general principles extracted where possible. We conclude that it is possible to conduct a trial that balances approaches that support internal validity (e.g. careful design of proformas, accurate case identification, control over data quality and high retention rates) with those that favour generalisability (e.g. ‘real world’ setting and low rates of exclusion). Strategies, such as Rapid Ethical Assessment, that increase researchers’ understanding of the study setting and inclusion of hard-to-reach participants are likely to have resource and time implications, but are vital in achieving an appropriate balance.

Trial registration

ISRCTN67805210, registered 24/01/2013.

Global epidemiology of podoconiosis: A systematic review

Background

Podoconiosis is one of the few diseases that could potentially be eliminated within one generation. Nonetheless, the global distribution of the disease remains largely unknown. The global atlas of podoconiosis was conceived to define the epidemiology and distribution of podoconiosis through dedicated surveys and assembling the available epidemiological data.

Methods

We have synthesized the published literature on the epidemiology of podoconiosis. Through systematic searches in SCOPUS and MEDLINE from inception to February 14, 2018, we identified observational and population-based studies reporting podoconiosis. To establish existence of podoconiosis, we used case reports and presence data. For a study to be included in the prevalence synthesis, it needed to be a population-based survey that involved all residents within a specific area. Studies that did not report original data were excluded. We undertook descriptive analyses of the extracted data. This study is registered with PROSPERO, number CRD42018084959.

Results

We identified 3,260 records, of which 27 studies met the inclusion criteria. Podoconiosis was described to exist or be endemic in 32 countries, 18 from the African Region, 3 from Asia and 11 from Latin America. Overall, podoconiosis prevalence ranged from 0·10% to 8.08%, was highest in the African region, and was substantially higher in adults than in children and adolescents. The highest reported prevalence values were in Africa (8.08% in Cameroon, 7.45% in Ethiopia, 4.52% in Uganda, 3.87% in Kenya and 2.51% in Tanzania). In India, a single prevalence of 0.21% was recorded from Manipur, Mizoram and Rajasthan states. None of the Latin American countries reported prevalence data.

Conclusion

Our data suggest that podoconiosis is more widespread in the African Region than in the rest of the regions, although this could be related to the fact that most podoconiosis epidemiological research has been focused in the African continent. The assembled dataset confirms that comprehensive podoconiosis control strategies such as promotion of footwear and personal hygiene are urgently needed in endemic parts of Africa. Mapping, active surveillance and a systematic approach to the monitoring of disease burden must accompany the implementation of podoconiosis control activities.

Podoconiosis is one of the Neglected Tropical Diseases, and causes painful and massive swelling of the lower legs. Despite the importance of the disease, its global distribution and epidemiology are poorly understood. We conducted a systematic review to assess the global epidemiology of podoconiosis. We found that podoconiosis was described to exist or be endemic in 32 countries, 18 from Africa, 3 from Asia and 11 from Latin America. Almost all prevalence data recorded corresponded to the African region. None of the Latin American countries reported prevalence data, although some countries are suspected to be endemic. We recommend that comprehensive podoconiosis control strategies such as promotion of footwear and personal hygiene are urgently needed in endemic countries in the African Region. Mapping, active surveillance and a systematic approach to the monitoring of disease burden must accompany the implementation of podoconiosis control activities.

Mapping the geographical distribution of podoconiosis in Cameroon using parasitological, serological, and clinical evidence to exclude other causes of lymphedema

Background

Podoconiosis is a non-filarial elephantiasis, which causes massive swelling of the lower legs. It was identified as a neglected tropical disease by WHO in 2011. Understanding of the geographical distribution of the disease is incomplete. As part of a global mapping of podoconiosis, this study was conducted in Cameroon to map the distribution of the disease. This mapping work will help to generate data on the geographical distribution of podoconiosis in Cameroon and contribute to the global atlas of podoconiosis.

Methods

We used a multi‐stage sampling design with stratification of the country by environmental risk of podoconiosis. We sampled 76 villages from 40 health districts from the ten Regions of Cameroon. All individuals of 15-years old or older in the village were surveyed house-to-house and screened for lymphedema. A clinical algorithm was used to reliably diagnose podoconiosis, excluding filarial-associated lymphedema. Individuals with lymphoedema were tested for circulating Wuchereria bancrofti antigen and specific IgG4 using the Alere Filariasis Test Strips (FTS) test and the Standard Diagnostics (SD) BIOLINE lymphatic filariasis IgG4 test (Wb123) respectively, in addition to thick blood films. Presence of DNA specific to W. bancrofti was checked on night blood using a qPCR technique.

Principal findings

Overall, 10,178 individuals from 4,603 households participated in the study. In total, 83 individuals with lymphedema were identified. Of the 83 individuals with lymphedema, two were found to be FTS positive and all were negative using the Wb123 test. No microfilaria of W. bancrofti were found in the night blood of any individual with clinical lymphedema. None were found to be positive for W. bancrofti using qPCR. Of the two FTS positive cases, one was positive for Mansonella perstans DNA, while the other harbored Loa loa microfilaria. Overall, 52 people with podoconiosis were identified after applying the clinical algorithm. The overall prevalence of podoconiosis was found to be 0.5% (95% [confidence interval] CI; 0.4–0.7). At least one case of podoconiosis was found in every region of Cameroon except the two surveyed villages in Adamawa. Of the 40 health districts surveyed, 17 districts had no cases of podoconiosis; in 15 districts, mean prevalence was between 0.2% and 1.0%; and in the remaining eight, mean prevalence was between 1.2% and 2.7%.

Conclusions

Our investigation has demonstrated low prevalence but almost nationwide distribution of podoconiosis in Cameroon. Designing a podoconiosis control program is a vital next step. A health system response to the burden of podoconiosis is important, through case surveillance and morbidity management services.

Podoconiosis is a geochemical neglected tropical disease, which causes massive swelling of the lower legs and feet. Although podoconiosis is one of the major causes of lower leg swelling worldwide, understanding of the geographical distribution of the disease is incomplete. In Cameroon, few studies have been conducted, and these have indicated varied and localized distribution of the disease. We conducted this countrywide mapping survey to determine the prevalence and spatial distribution of podoconiosis in Cameroon. We undertook nationwide mapping of podoconiosis in Cameroon by surveying 10,178 individuals from 4,603 households, in 76 communities. During the survey, individuals with lymphedema underwent a rapid-format antigen antibody test, and a thick blood film (TBF) for microscopic examination, as a confirmatory tool for detecting W. bancrofti micro filarial. Peripheral night blood and parasite DNA detection was used to exclude lymphatic filariasis, and a clinical history and physical examination was conducted to diagnosis podoconiosis. The overall prevalence of podoconiosis was found to be 0.5%. At least one case of podoconiosis was found in every region of Cameroon except Adamawa, where in the two surveyed villages no cases of podoconiosis were identified. Our investigation has demonstrated low prevalence but almost nationwide distribution of podoconiosis in Cameroon. Designing a podoconiosis control program is a vital next step. A health system response to the burden of podoconiosis is important, through case surveillance and morbidity management services.