Prevalence of soil transmitted helminths and impact of Albendazole on parasitic indices in Kotto Barombi and Marumba II villages (South-West Cameroon)

This study assessed the actual prevalence of geohelminths and the impact of albendazole on parasitic indices in Kotto Barombi and Marumba II. Stools samples were collected from 420 school children and examined using the Kato-katz faecal technique. Participants were treated with 600 mg of albendazole. Baseline prevalence of infections and mean parasite loads were 26.4% and 6226.9e/g (Ascaris lumbricoides), 31.0% and 252.4 e/g (Trichuris trichiura), and 1.4% and 468.0e/g (Necator americanus). Four children (0.9%) were infected with Strongyloides stercoralis. A significant difference of prevalence was observed between the two villages for A. lumbricoides (P = 0.0001) and T. trichiura (P = 0.0005), and parasite loads for T. trichiura (P = 0.0001). Single infection (T. trichiura or A. lumbricoides) and double infection (A. lumbricoides - T. trichiura) were more prevalent. Post treatment control showed a decrease of prevalence and mean parasite load to 24.4% and 2969.5e/g (A. lumbricoides), and 24.0% and 112.8e/g (T. trichiura), and 0.0% for N. americanus and S. stercoralis. Efficacy and egg reduction rates were 84.6% and 55.3% (T. trichiura), 82.0% and 52.2% (A. lumbricoides), and 100.0% for N. americanus and S. stercoralis. These results suggest that geohelminths infections remain a serious health problem in school children in Kotto Barombi focus

Spatial distribution of podoconiosis in relation to environmental factors in Ethiopia: a historical review

BACKGROUND An up-to-date and reliable map of podoconiosis is needed to design geographically targeted and cost-effective intervention in Ethiopia. Identifying the ecological correlates of the distribution of podoconiosis is the first step for distribution and risk maps. The objective of this study was to investigate the spatial distribution and ecological correlates of podoconiosis using historical and contemporary survey data. METHODS Data on the observed prevalence of podoconiosis were abstracted from published and unpublished literature into a standardized database, according to strict inclusion and exclusion criteria. In total, 10 studies conducted between 1969 and 2012 were included, and data were available for 401,674 individuals older than 15 years of age from 229 locations. A range of high resolution environmental factors were investigated to determine their association with podoconiosis prevalence, using logistic regression. RESULTS The prevalence of podoconiosis in Ethiopia was estimated at 3.4% (95% CI 3.3%-3.4%) with marked regional variation. We identified significant associations between mean annual Land Surface Temperature (LST), mean annual precipitation, topography of the land and fine soil texture and high prevalence of podoconiosis. The derived maps indicate both widespread occurrence of podoconiosis and a marked variability in prevalence of podoconiosis, with prevalence typically highest at altitudes >1500 m above sea level (masl), with >1500 mm annual rainfall and mean annual LST of 19-21°C. No (or very little) podoconiosis occurred at altitudes 24°C. CONCLUSION Podoconiosis remains a public health problem in Ethiopia over considerable areas of the country, but exhibits marked geographical variation associated in part with key environmental factors. This is work in progress and the results presented here will be refined in future work

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 in the field 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

The therapeutic efficacy and macrofilaricidal activity of doxycycline for the treatment of river blindness

Background. Onchocerca volvulus and lymphatic filariae, causing river blindness and elephantiasis, depend on endosymbiotic Wolbachia bacteria for growth, development, fertility, and survival. Clinical trials have shown that doxycycline treatment eliminates Wolbachia, causing long-term sterilization of adult female filariae and effecting potent macrofilaricidal activity. The continual reinfection by drug-naive worms that occurs in these trial settings dilutes observable anti-Wolbachia and antifilarial effects, making it difficult to estimate therapeutic efficacy and compare different doxycycline regimens, evaluated at different times after treatment. Methods. A meta-analytical modeling framework is developed to link all usable data collected from clinical trials measuring the Wolbachia status and viability of individual female adult worms collected at various times after treatment with 4, 5, or 6 weeks of daily 100 or 200 mg oral doxycycline. The framework is used to estimate efficacy parameters that are not directly measurable as trial outcomes. Results. The estimated efficacy of doxycycline (the maximum proportional reduction in the percentage of adult female O. volvulus positive for Wolbachia) is 91%–94% on average, irrespective of the treatment regimen. Efficacy is >95% in the majority of trial participants. The life span of Wolbachia-depleted worms is reduced by 70%–80%, from approximately 10 years to 2–3 years. Conclusions. The efficacy parameters are pertinent to the prospects of using doxycycline on a “test and treat” basis for onchocerciasis control and confirm doxycycline as a potent macrofilaricidal therapy. The modeling approach is more generally relevant to the design and evaluation of clinical trials for antifilarial drugs conducted in endemic settings

Podoconiosis in East and West Gojam Zones, Northern Ethiopia

Background: Podoconiosis is a neglected tropical disease (NTD) that is prevalent in red clay soil-covered highlands of tropical Africa, Central and South America, and northern India. It is estimated that up to one million cases exist in Ethiopia. This study aimed to estimate the prevalence of podoconiosis in East and West Gojam Zones of Amhara Region in northern Ethiopia. Methodology/Principal Findings: A cross-sectional household survey was conducted in Debre Eliyas and Dembecha woredas (districts) in East and West Gojam Zones, respectively. The survey covered all 17,553 households in 20 kebeles (administrative subunits) randomly selected from the two woredas. A detailed structured interview was conducted on 1,704 cases of podoconiosis identified in the survey. Results: The prevalence of podoconiosis in the population aged 15 years and above was found to be 3.3% (95% CI, 3.2% to 3.6%). 87% of cases were in the economically active age group (15–64 years). On average, patients sought treatment five years after the start of the leg swelling. Most subjects had second (42.7%) or third (36.1%) clinical stage disease, 97.9% had mossy lesions, and 53% had open wounds. On average, patients had five episodes of acute adenolymphangitis (ALA) per year and spent a total of 90 days per year with ALA. The median age of first use of shoes and socks were 22 and 23 years, respectively. More men than women owned more than one pair of shoes (61.1% vs. 50.5%; x2 = 11.6 p = 0.001). At the time of interview, 23.6% of the respondents were barefoot, of whom about two-thirds were women. Conclusions: This study showed high prevalence of podoconiosis and associated morbidities such as ALA, mossy lesions and open wounds in northern Ethiopia. Predominance of cases at early clinical stage of podoconiosis indicates the potential for reversing the swelling and calls for disease prevention interventions

Projected Number of People With Onchocerciasis-Loiasis Coinfection in Africa, 1995 to 2025

BACKGROUND: Onchocerciasis elimination through mass drug administration (MDA) is hampered by coendemicity of Loa loa, as people with high L. loa microfilariae (mf) density can develop serious adverse events (SAEs) after ivermectin treatment. We assessed the geographical overlap of onchocerciasis and loiasis prevalence and estimated the number of coinfected individuals at risk of post-ivermectin SAEs in West and Central Africa from 1995 to 2025. METHODS: Focusing on regions with suspected loiasis transmission in 14 countries, we overlaid precontrol maps of loiasis and onchocerciasis prevalence to calculate precontrol prevalence of coinfection by 5 km2 × 5 km2 pixel, distinguishing different categories of L. loa mf intensity. Using statistical and mathematical models, we predicted prevalence of both infections and coinfection for 2015 and 2025, accounting for the impact of MDA with ivermectin. RESULTS: The number of people infected with onchocerciasis was predicted to decline from almost 19 million in 1995 to 4 million in 2025. Of these, 137 000 people were estimated to also have L. loa hypermicrofilaremia (≥20 000 L. loa mf/mL) in 1995, declining to 31 000 in 2025. In 2025, 92.8% of coinfecte

Burden of podoconiosis in poor rural communities in Guliso woreda, western Ethiopia

Background. Podoconiosis is an environmental lymphoedema affecting people living and working barefoot on irritant red clay soil. Podoconiosis is relatively well described in southern Ethiopia, but remains neglected in other parts of the Ethiopian highlands. This study aimed to assess the burden of podoconiosis in rural communities in western Ethiopia. Methodology/Principal Findings. A cross-sectional study was conducted in Gulliso woreda (district), west Ethiopia. A household survey in the 26 rural kebeles (villages) of this district was conducted to identify podoconiosis patients and to measure disease prevalence. A more detailed study was done in six randomly selected kebeles to describe clinical features of the disease, patients’ experiences of foot hygiene, and shoe wearing practice. 1,935 cases of podoconiosis were registered, giving a prevalence of 2.8%. The prevalence was higher in those aged 15 – 64 years (5.2%) and in females than males (prevalence ratio 2.6:1). 90.3% of patients were in the 15 – 64 year age group. In the detailed study, 335 cases were interviewed and their feet assessed. The majority of patients were farmers, uneducated, and poor. Two-third of patients developed the disease before the age of thirty. Almost all patients (97.0%) had experienced adenolymphangitis (ALA - red, hot legs, swollen and painful groin) at least once during the previous year. Patients experienced an average of 5.5 ALA episodes annually, each of average 4.4 days, thus 24 working days were lost annually. The incidence of ALA in podoconiosis patients was higher than that reported for filariasis in other countries. Shoe wearing was limited mainly due to financial problems. Conclusions. We have documented high podoconiosis prevalence, frequent adenolymphangitis and high disease-related morbidity in west Ethiopia. Interventions must be developed to prevent, treat and control podoconiosis, one of the core neglected tropical diseases in Ethiopia

Macrofilaricidal Activity after Doxycycline Only Treatment of Onchocerca volvulus in an Area of Loa loa Co-Endemicity: A Randomized Controlled Trial

The control of onchocerciasis in Africa relies on the sustained delivery of ivermectin. In certain areas, annual treatments delivered with high population coverage for at least 15–17 years can break transmission. In other endemic settings this strategy alone is thought to be insufficient to eradicate the disease. One of the major limitations occurs in areas that are co-endemic with another filarial infection caused by Loa loa, due to the risk of a rare severe adverse event associated with the rapid killing of L. loa microfilariae in heavily parasitized individuals. There are also concerns over recent evidence of reduced efficacy of ivermectin and the possible development of resistance. An alternative approach is to target the Wolbachia bacterial endosymbionts of Onchocerca volvulus with the antibiotic, doxycycline. In an area of Cameroon co-endemic for onchocerciasis and loiasis we conducted a trial comparing doxycycline with or without ivermectin treatment to ivermectin treatment alone. A six-week course of doxycycline delivers macrofilaricidal and sterilizing activities, which is not dependent upon co-administration of ivermectin. Doxycycline is well tolerated in patients co-infected with moderate intensities of L. loa microfilariae. The trial indicates that anti-wolbachial therapy is a feasible alternative to ivermectin in communities co-endemic for onchocerciasis and loiasis