Severe tungiasis in underprivileged communities: case series from Brazil

Management of very severe tungiasis cases through repeated community-based treatment with a dimeticone oil formula: A longitudinal study in a hyperendemic region in Uganda

Tungiasis (sand flea disease) is a neglected tropical disease that is endemic in Sub-Saharan Africa and Latin America. Tungiasis causes pain, mobility restrictions, stigmatisation and reduced quality of life. Very severe cases with hundreds of sand fleas have been described, but treatment of such cases has never been studied systematically. During a larger community-based tungiasis control programme in a hyperendemic region in Karamoja, northeastern Uganda, 96 very severe tungiasis cases were identified and treated with the dimeticone formula NYDA®. They were repeatedly followed-up and treated again when necessary. The present study traces tungiasis frequency, intensity and morbidity among these 96 individuals over 2 years. At baseline, very severe tungiasis occurred in all age groups, including young children. Throughout the intervention, tungiasis frequency decreased from 100% to 25.8% among the 96 individuals. The overall number of embedded sand fleas in this group dropped from 15,648 to 158, and the median number of embedded sand fleas among the tungiasis cases decreased from 141 to four. Walking difficulties were reported in 96.9% at the beginning and in 4.5% at the end of the intervention. Repeated treatment with the dimeticone formula over 2 years was a successful strategy to manage very severe cases in a hyperendemic community. Treatment of very severe cases is essential to control the spread and burden of tungiasis in endemic communities.

Developing low-cost house floors to control tungiasis in Kenya - a feasibility study

CONTEXT

Tungiasis is a neglected tropical skin disease endemic in resource-poor communities. It is caused by the penetration of the female sand flea, Tunga penetrans, into the skin causing immense pain, itching, difficulty walking, sleeping and concentrating on school or work. Infection is associated with living in a house with unsealed earthen house floors.

METHODS

This feasibility study used a community-based co-creation approach to develop and test simple, locally appropriate, and affordable flooring solutions to create a sealed, washable floor for the prevention of tungiasis. Locally used techniques were explored and compared in small slab trials. The floor with best strength and lowest cost was pilot trialed in 12 households with tungiasis cases to assess its durability and costs, feasibility of installation in existing local houses using local masons and explore community perceptions. Disease outcomes were measured to estimate potential impact.

RESULTS

It was feasible to build the capacity of a community-based organization to conduct research, develop a low-cost floor and conduct a pilot trial. The optimal low-cost floor was stabilized local subsoil with cement at a 1:9 ratio, installed as a 5 cm depth slab. A sealed floor was associated with a lower mean infection intensity among infected children than in control households (aIRR 0.53, 95%CI 0.29-0.97) when adjusted for covariates. The cost of the new floor was US$3/m2 compared to $10 for a concrete floor. Beneficiaries reported the floor made their lives much easier, enabled them to keep clean and children to do their schoolwork and eat while sitting on the floor. Challenges encountered indicate future studies would need intensive mentoring of masons to ensure the floor is properly installed and households supervised to ensure the floor is properly cured.

CONCLUSION

This study provided promising evidence that retrofitting simple cement-stabilised soil floors with locally available materials is a feasible option for tungiasis control and can be implemented through training of community-based organisations. Disease outcome data is promising and suggests that a definitive trial is warranted. Data generated will inform the design of a fully powered randomized trial combined with behaviour change communications.

TRIAL REGISTRATION

ISRCTN 62801024 (retrospective 07.07.2023).

Tungiasis: Participation of Cats and Chickens in the Dispersion and Maintenance of the Disease in an Endemic Tourist Area in Brazil

Tunga spp. are fleas commonly found in impoverished tropical regions. In Vila Juerana, a tourist community in Ilheus, Bahia, Brazil, where tungiasis is endemic, dogs are the main host of fleas during their life cycle. However, there is no information about the role of cats and chickens in tungiasis in the village. Of the 272 households investigated, 112 had domestic animals, 48 had only dogs, 28 had only cats, and nine had only chickens. Of the 27 households with cohabitation among species, 16 had cats and dogs, eight had chickens and dogs, and three had dogs, cats, and chickens. The injuries due to tungiasis were ranked according to the Fortaleza classification, considering stages I, II, and III as viable lesions. The paws/feet of 71/111 (63.9%) cats and 173/439 (39.4%) chickens were inspected. Dogs that lived with positive cats and chickens also were inspected. Among the 38% (27/7; 95% IC 26.74-49.32) positive cats, 16 cohabited houses with infected dogs but none lived with positive chickens. Of the chickens, 2.3% (4/173; 95% IC 0.07-4.5) had lesions caused by tungiasis. In each household where a cat was infected, the dog was also positive. Two chickens cohabited with an infected dog and the other two did not coexist with other species. Cohabitation with infected dogs and the absence of house confinement restrictions in Vila Juerana make cats important carriers that spread tungiasis in this community. Chickens had a low frequency of tungiasis lesions despite living in proximity to infected dogs and cats.

Tungiasis Stigma and Control Practices in a Hyperendemic Region in Northeastern Uganda

Neglected tropical diseases are known to be highly stigmatized conditions. This study investigates tungiasis-related stigma and control practices in the impoverished Napak District in rural northeastern Uganda, where tungiasis is hyperendemic and effective treatment is unavailable. We conducted a questionnaire survey with the main household caretakers (n = 1329) in 17 villages and examined them for tungiasis. The prevalence of tungiasis among our respondents was 61.0%. Questionnaire responses showed that tungiasis was perceived as a potentially serious and debilitating condition and that tungiasis-related stigma and embarrassment were common. Among the respondents, 42.0% expressed judging attitudes, associating tungiasis with laziness, carelessness, and dirtiness, and 36.3% showed compassionate attitudes towards people with tungiasis. Questionnaire responses further indicated that people made an effort to keep their feet and house floors clean (important tungiasis prevention measures), but lack of water was a common problem in the area. The most frequent local treatment practices were hazardous manual extraction of sand fleas with sharp instruments and application of various and sometimes toxic substances. Reliable access to safe and effective treatment and water are therefore key to reducing the need for dangerous treatment attempts and breaking the vicious cycle of tungiasis stigma in this setting marked by poverty.

Characterization of tungiasis infection and morbidity using thermography in Kenya revealed higher disease burden during COVID-19 school closures

BACKGROUND

Tungiasis is a neglected tropical skin disease caused by the sand flea Tunga penetrans. Female fleas penetrate the skin, particularly at the feet, and cause severe inflammation. This study aimed to characterize disease burden in two highly affected regions in Kenya, to test the use of thermography to detect tungiasis-associated inflammation and to create a new two-level classification of disease severity suitable for mapping, targeting, and monitoring interventions.

METHODS

From February 2020 to April 2021, 3532 pupils age 8-14 years were quasi-randomly selected in 35 public primary schools and examined for tungiasis and associated symptoms. Of the infected pupils, 266 were quasi-randomly selected and their households visited, where an additional 1138 family members were examined. Inflammation was assessed using infra-red thermography. A Clinical score was created combining the number of locations on the feet with acute and chronic symptoms and infra-red hotspots.

RESULTS

The overall prevalence of tungiasis among all the school pupils who were randomly selected during survey rounds 1 and 3 was 9.3% [95% confidence interval (CI): 8.4-10.3]. Based on mixed effects logistic models, the odds of infection with tungiasis among school pupils was three times higher in Kwale (coastal Kenya) than in Siaya [western Kenya; adjusted odds ratio (aOR) = 0.36, 95% CI: 0.18-0.74]; three times higher in males than in females (aOR = 3.0, 95% CI: 2.32-3.91) and three times lower among pupils sleeping in a house with a concrete floor (aOR = 0.32, 95% CI: 0.24-0.44). The odds of finding an infected person among the household population during surveys before the COVID-19 pandemic was a third (aOR = 0.32, 95% CI: 0.19-0.53) of that when schools were closed due to COVID-19 restrictions and approximately half (aOR = 0.44, 95% CI: 0.29-0.68) in surveys done after school re-opening (round 3). Infection intensity was positively correlated with inflammation as measured by thermography (Spearman's rho = 0.68, P < 0.001) and with the clinical score (rho = 0.86, P < 0.001). Based on the two-level classification, severe cases were associated with a threefold higher level of pain (OR = 2.99, 95% CI: 2.02-4.43) and itching (OR = 3.31, 95% CI: 2.24-4.89) than mild cases.

CONCLUSIONS

Thermography was a valuable addition for assessing morbidity and the proposed two-level classification of disease severity clearly separated patients with mild and severe impacts. The burden of tungiasis was considerably higher in households surveyed during COVID-19 restrictions suggesting underlying risks are found in the home environment more than in school.

Prevalence and Infection Intensity of Human and Animal Tungiasis in Napak District, Karamoja, Northeastern Uganda

Tungiasis is an important but highly neglected cause of morbidity in resource-poor communities in Latin America and sub-Saharan Africa. Data upon which implementation of control measures can be based are scarce. Before piloting an integrated tungiasis control program in three parishes of Napak district, Uganda, a cross-sectional survey involving the systematic examination of humans and domestic mammals was implemented to establish the occurrence patterns of tungiasis. The study population was 5482 residents, of which 4035 (73.6%) participated in the study. The prevalence of tungiasis in humans was 62.8% (95% CI: 61.3-64.3%), with slightly more males than females affected (p = 0.01). Age-specific prevalence and intensity of human tungiasis followed an S-curve pattern, with children of 5-14 years and the elderly (≥60 years) being the most affected. Half of all lesions (50%) had been manipulated by sharp objects. The prevalence of tungiasis in animals was lower (14.2%, 95% CI: 10.9-18.0) than that of humans (p < 0.001). Animal tungiasis occurred in decreasing order of frequency in pigs (80%), dogs (24%), goats (16.3%), cats (8.1%) and sheep (4.9%). In conclusion, human tungiasis was highly prevalent but animal infections were comparatively few in the study area. Nevertheless, effective control measures should be based on One Health principles.

Spatial Distribution of Off-Host Stages of Tunga penetrans in the Soil within the Home Range of Nine Infected Dogs in An Endemic Tourist Area in Brazil

Tungiasis is a neglected disease caused by the sand flea Tunga penetrans, and dogs are considered the main reservoirs in Brazil. This study aimed to identify the role of dogs as tungiasis dispersers and to investigate the presence of T. penetrans in the soil of an endemic tourist area. Nine dogs infected by T. penetrans were included in this study and received GPS collars to analyze their movement through the village. Duplicate sand samples were collected in different areas of the community. Those areas were classified as peridomicile (n = 110), open area (n = 110), beach (n = 50), and river (n = 58). The analysis of the points recorded by the collars showed that the dogs roamed throughout the community, potentially facilitating the spread of the disease. Samples contaminated with developmental forms of the parasite were found in the circulation area of three dogs. Adult fleas were found in 3/328 samples. These data emphasize that infected dogs' roaming can influence the fleas' dispersion in the soil. Statistically, none of the study variables had a significant correlation (p > 0.5) with the presence of T. penetrans in the area analyzed. This study was the first to assess infected dogs' role as tungiasis propagators.

Protocol for a Randomized Control Trial for Tungiasis Treatment in Homa Bay County, Kenya: Dimeticone versus Sodium Carbonate

Tungiasis, a World Health Organization neglected tropical disease, is caused by the female sand flea. Most clinical trials for tungiasis use expensive or impractical drugs, which are difficult for residents to use. However, in western Kenya, communities successfully treat tungiasis with sodium carbonate. We hypothesise that the topical risk-difference of 5% sodium carbonate is no more than 10% non-inferior to dimeticone (NYDA^®) for tungiasis treatment. This is a protocol for a non-inferiority study, which will be randomised and with an observer-blinded control. The study will have two arms: 5% sodium carbonate and NYDA^®, one on each foot, and will take place at state primary schools in Homa Bay County, Kenya. Fleas identified among school children aged 8-14 years with sand-flea lesions will be enrolled in the study. For each participant, the viability of the embedded fleas, clinical signs including inflammation, and symptoms will be monitored for seven days after treatment. The proportion of dead fleas will be compared in the primary analysis. All adverse events will be monitored throughout the study period. We expect to identify the most effective treatment between sodium carbonate and NYDA^® for tungiasis, which can be adopted in the community.

Efficacy of oral fluralaner (Bravecto) against Tunga penetrans in dogs: A negative control, randomized field study in an endemic community in Brazil

The sand flea Tunga penetrans is one of the zoonotic agents of tungiasis, a parasitic skin disease of humans and animals. The dog is one of its main reservoirs. This negatively controlled, randomized, double-masked clinical trial evaluated the therapeutic and residual efficacy of fluralaner for treatment of dogs naturally infested with T. penetrans. Sixty-two dogs from an endemically affected community in Brazil were randomly assigned to either receive oral fluralaner (Bravecto chewable tablets) at a dose of 25 to 56 mg fluralaner/kg body weight, or no treatment (31 dogs per group). Dogs were clinically examined using a severity score for acute canine tungiasis (SCADT), parasitological examinations as defined by the Fortaleza classification, and pictures of lesions on days 0 (inclusion and treatment), 7 ± 2, 14 ± 2, 21 ± 2, 28 ± 2, 60 ± 7, 90 ± 7, 120 ± 7 and 150 ± 7. The percentage of parasite-free dogs after treatment was >90% between days 14 and 90 post-treatment with 100% efficacy on study days 21, 28 and 60. Sand flea counts on fluralaner treated dogs were significantly lower (p<0.025) than control dogs on all counts from day 7 to 120. The number of live sand fleas on treated dogs was reduced by > 90% on day 7, > 95% on days 14 and 90, and 100% from day 21 to 60, and with a significant difference between groups from day 7 to 120. From day 7 to day 120, mean SCADT scores were significantly reduced in treated dogs with a mean of 0.10 compared to 1.54 on day 120 in untreated dogs. Therefore, a single oral fluralaner administration is effective for treating and achieving long lasting (> 12 weeks) prevention for tungiasis in dogs.

Tungiasis is a dermatological disease that affects humans and animals infested with sand fleas (Tunga spp.), especially in communities exposed to contaminated sandy and dry soil, where living conditions are precarious and access to basic health is limited. These sand fleas penetrate host skin and cause severe acute and chronic injuries that can dramatically compromise the host’s health. Dogs are a primary reservoir and disseminator of these fleas in South America. In this clinical field trial, the efficacy of a single oral dose of fluralaner (Bravecto chewable tablets) was evaluated for treatment and prevention of tungiasis in dogs in an endemic area of Brazil. The treatment was assessed through absence of live sand fleas and resolution of characteristic tungiasis skin lesions. Fluralaner was 100% effective from the third to the eighth week post-treatment, eliminated live sand fleas and protected against new infestations during the study. Therefore, fluralaner proved to be an excellent therapeutic option for treatment and a highly effective control option for canine tungiasis.

Prevalence of Tungiasis and its risk factors of among children of Mettu woreda, southwest Ethiopia, 2020

Tungiasis is caused by the flea tunga penetrans and results in painful skin lesions, skin infections, and permanent disability. However, limited information is available that shows the magnitude of the problem and its risk factors that help for intervention in Ethiopia. The goal of this study was to determine the prevalence and risk factors of tungiasis in children aged 5 to 14 in Mettu woreda in 2020. A community based cross sectional study was conducted among randomly selected kebeles of Mettu woreda, in Southwest Ethiopia. To select study participants, multistage sampling was used. The data were collected through physical examination of the children, interview of parents/guardians of the children, and observation of the home environment using checklists and questionnaires. The descriptive analysis was done for socio-demographic characteristics, prevalence of tungiasis, and housing conditions. A logistic regression analysis was performed, and variables in multivariable regression reported odds ratios and their 95% confidence intervals once the variables were identified using a p-value of 0.05 as a risk factor of statistical significance. The prevalence of tungiasis among children 5–14 years of age in Mettu rural woreda was 52 percent (n = 821). As a risk factor, large family size (AOR: 2.9, 95% CI: 2.13, 4.40); school attendance (AOR: 1.5, 95% CI: 1.02, 2.18), floor inside the house (AOR: 3.8, 95% CI: 1.76, 8.43); having sleeping bed (AOR: 0.16, 95% CI: 0.03, 0.82); access to protected water sources (AOR: 0.24, 95% CI: 0.15, 0.39); access to improved toilet facilities(AOR: 0.63: 95% CI: 0.44, 0.89); access to electric services (AOR: 0.30, 95% CI: 0.15, 0.62); and lack of own farmland (AOR: 0.36, 95% CI: 0.26, 0.50) were found. Therefore, planning and implementation of interventions focus on those risk factors that are particularly important. Water, sanitation and hygiene interventions, and livelihood improvement interventions are required to solve the problem in the setting.

Therapeutic Potential of Tea Tree Oil for Tungiasis

Tungiasis (sand flea disease) is a neglected tropical disease caused by penetration of female sand fleas, Tunga penetrans, into a person's skin usually in their feet. The disease inflicts immense pain and suffering on millions of people, particularly children. The condition is most prevalent in Latin America, the Caribbean, and sub-Saharan Africa. Currently, there is no standard drug treatment for tungiasis. The available treatment options are fairly limited and unrealistic to use in endemic areas; as a result, in desperation, the affected people do more harm to themselves by extracting the fleas with non-sterile instruments, further exposing themselves to secondary bacterial infections and/or transmission of diseases such as hepatitis B virus, hepatitis C virus, or HIV. This highlights the urgent need for simpler, safer, and effective treatment options for tungiasis. Tea tree oil (TTO) has long been used as an antiseptic with extensive safety and efficacy data. The evidence on parasiticidal properties of TTO against ectoparasites such as head lice, mites, and fleas is also compelling. The purpose of this review is to discuss the current tungiasis treatment challenges in endemic settings and highlight the potential role of TTO in the treatment of tungiasis.

Assessment of the role played by domestic animals in jigger infection in Kandara sub-county, Kenya (case control study)

Introduction

tungiasis is an ectoparasitosis caused by penetration of female sand flea, Tunga penetrans, into the skin of the susceptible animal and the consequent hypertrophy of the parasite. The objective of this study was to assess the association between domestic animals and jigger infection among the residents of Kandara sub-county in central Kenya.

Methods

this was a case-control study that involved 776 individuals. Half of this number entailed case group who were jigger infected while the other half was the control, composed of jigger free participants. Structured questionnaires were, administered among the heads of the households to which the participants belonged to gather information concerning the animals they kept. Univariate analysis was, applied.

Results

in this study, there were significant differences in age (P=0.008) between the two groups. Disparities in source of income (P<0.001) and level of education (P<0.001) came out as very significant factors in jigger infection. The case group was 10 times more likely to keep dogs than the control(9.6; 95% CI, 5.9-15.6). Case group was also 7 times more likely to rear chicken in comparison to the control (6.6; 95%, 4.2-10.4). The case group was 12 times more likely to let dogs loose in the compound in comparison to the control (12.1: 95%, 5.9-24.5). When compared to the control, this group was also 17 times more likely to keep chicken inside their houses (16.7: 95% CI, 6.8-35.9). Conclusion: there is a very high association between domestic animals and occurrence of tungiasis in Kandara sub-county.

Risk factors for scabies, tungiasis, and tinea infections among schoolchildren in southern Ethiopia: A cross-sectional Bayesian multilevel model

Background

Skin problems cause significant sickness in communities with poor living conditions, but they have received less attention in national or global health studies because of their low mortality rates. In many developing regions, the prevalence of parasitic skin diseases among schoolchildren is not reported. Previous studies thus have attempted to identify risk factors for these conditions using the frequentist approach. This study aimed to assess the occurrence and risk factors of skin infections among rural schoolchildren in southern Ethiopia by combining a frequentist and a Bayesian approach.

Methodology/Principal findings

Using three-stage random sampling, we assessed 864 schoolchildren aged 7–14 years from the Wonago district in southern Ethiopia. We detected potential risk factors for scabies, tungiasis, and tinea infections and recorded their hygienic practices and socio-demographic information. The frequentist model revealed a clustering effect of 8.8% at the classroom level and an insignificant effect at the school level. The Bayesian model revealed a clustering effect of 16% at the classroom level and 5.3% at the school level. Almost three-fourths of the sample had at least one type of skin problem, and boys were at higher overall risk than girls (adjusted odds ratio [aOR] 1.55 [95% Bayesian credible interval [BCI] 1.01, 2.28). Risk factors included unclean fingernails (aOR 1.85 [95% BCI 1.08, 2.97]); not washing the body (aOR 1.90 [95% BCI 1.21, 2.85]) and hair (aOR 3.07 [95% BCI 1.98, 4.57]) with soap every week; sharing a bed (aOR 1.97 [95% BCI 1.27, 2.89]), clothes (aOR 5.65 [95% BCI 3.31, 9.21]), or combs (aOR 3.65 [95% BCI 2.28, 5.53]); and living in a poor household (aOR 1.76 [95% BCI 1.03, 2.83]). Washing legs and feet with soap daily was identified as a protective factor for each of the three skin diseases (aOR 0.23 [95% BCI 0.15, 0.33]).

Conclusions/Significance

We observed high variation in skin problems at the classroom level, indicating the presence of shared risk factors in these locations. The findings suggest the need to improve children’s personal hygiene via health education by schoolteachers and health workers.

Skin problems are common disorders in resource poor settings. Scabies and tungiasis are neglected tropical diseases causing significant sickness in communities with poor living conditions. Scabies is dermatosis caused by a burrowing mite, Sarcoptes scabiei var. hominis. Tungiasis is caused by a flea, Tunga penetrans, infesting the skin, usually on the feet or hands. Tinea infection is a fungal dermatophyte infection of the skin and the most common dermatological problem among schoolchildren in Ethiopia, especially tinea capitis. Application of a Bayesian approach to identify possible risk factors for these problems has seldom been used. We found that compared to the frequentist model, the Bayesian model better explained school- and classroom-level variations in skin problems among schoolchildren. Our findings also suggest that transmission of skin infections, especially fungal and scabies infections, frequently occurs in schools and classrooms. We identified several risk factors for these conditions, including low socioeconomic status; unclean fingernails; not washing with soap at least every week; and sharing beds, clothes, and combs. Thus, it is important to improve the personal hygiene of schoolchildren through education. Regular checkups by teachers also can improve skin health and related morbidity in rural schoolchildren in southern Ethiopia.

Treatment of tungiasis using a tea tree oil-based gel formulation: protocol for a randomised controlled proof-of-principle trial

INTRODUCTION

Tungiasis (sand flea disease or jigger infestation) is a neglected tropical disease caused by penetration of female sand fleas, Tunga penetrans, in the skin. The disease inflicts immense pain and suffering on millions of people, particularly children, in Latin America, the Caribbean and sub-Saharan Africa. Currently, there is no standard treatment for tungiasis, and a simple, safe and effective tungiasis treatment option is required. Tea tree oil (TTO) has long been used as a parasiticidal agent against ectoparasites such as headlice, mites and fleas with proven safety and efficacy data. However, current data are insufficient to warrant a recommendation for its use in tungiasis. This trial aims to generate these data by comparing the safety and efficacy of a 5% (v/w) TTO proprietary gel formulation with 0.05% (w/v) potassium permanganate (KMnO₄) solution for tungiasis treatment.

METHODS AND ANALYSIS

This trial is a randomised controlled trial (RCT) in primary schools (n=8) in South-Western Kenya. The study will include school children (n=88) aged 6-15 years with a confirmed diagnosis of tungiasis. The participants will be randomised in a 1:1 ratio to receive a 3-day two times a day treatment of either 5% TTO gel or 0.05% KMnO₄ solution. Two viable embedded sandflea lesions per participant will be targeted and the viability of these lesions will be followed throughout the study using a digital handheld microscope. The primary outcome is the proportion of observed viable embedded sand fleas that have lost viability (non-viable lesions) by day 10 (9 days after first treatment). Secondary outcomes include improvement in acute tungiasis morbidities assessed using a validated severity score for tungiasis, safety assessed through adverse events and product acceptability assessed by interviewing the participants to rate the treatment in terms of effectiveness, side effects, convenience, suitability and overall satisfaction.

ETHICS AND DISSEMINATION

The trial protocol has been reviewed and approved by the University of Canberra Human Research Ethics Committee (HREC-2019-2114). The findings of the study will be presented at scientific conferences and published in a peer-reviewed journal.

TRIAL REGISTRATION NUMBERS

Australian New Zealand Clinical Trials Registry (ACTRN12619001610123); PACTR202003651095100 and U1111-1243-2294.

Presence of dogs and proximity to a wildlife reserve increase household level risk of tungiasis in Kwale, Kenya

Introduction

Tungiasis is a ectopic skin disease caused by some species of fleas in the Tunga genus, most notably T. penetrans. The disease afflicts poor and marginalized communities in developing countries. Transmission of tungiasis comprises a complex web of factors including domesticated animals and wildlife. This research explores animal and environmental risk factors for tungiasis in an area adjacent to a wildlife reserve in Kwale, Kenya.

Methods

A two-stage complex sampling strategy was used. Households were selected from three areas in and around Kwale Town, Kenya, an area close to the Kenyan Coast. Households were listed as positive if at least one member had tungiasis. Each household was administered a questionnaire regarding tungiasis behaviors, domesticated animal assets, and wild animal species that frequent the peridomiciliary area. Associations of household tungiasis were tests with household and environmental variables using regression methods.

Results

The study included 319 households. Of these, 41 (12.85%) were found to have at least one person who had signs of tungiasis. There were 295 (92.48%) households that possessed at least one species of domesticated animal. It was reported that wildlife regularly come into the vicinity of the home 90.59% of households. Presence of dogs around the home (OR 3.85; 95% CI 1.84; 8.11) and proximity to the park were associated with increased risk for tungiasis infestation in humans in a multivariate regression model.

Conclusions

Human tungiasis is a complex disease associated with domesticated and wild animals. Canines in particular appear to be important determinants of household level risk.

Clinical interventions for tungiasis (sand flea disease): a systematic review

Tungiasis (sand flea disease) is an epidermal parasitic skin disease occurring in resource-limited communities. There is no standard treatment for tungiasis, and available treatment options are scarce. To our knowledge, this is the first systematic review aimed to assess randomised controlled trials (RCTs) investigating interventions for tungiasis. We systematically searched databases including MEDLINE (EBSCOhost), CENTRAL, CINAHL, PubMed, Web of Science, SciELO, LILACS and Embase (Scopus) for RCTs in any language, from inception of the databases until June 12, 2021. RCTs exploring preventive and therapeutic interventions for tungiasis were eligible. We used the revised Cochrane Collaboration's risk of bias tool to assess the risk of bias and Jadad scale to quantify the methodological quality of the RCTs. Of the 1839 identified records, only eight RCTs involving 808 participants were included, and several methodological deficiencies were identified in most of the trials. Trial interventions included: oral drugs niridazole and ivermectin and topical interventions of ivermectin lotion, metrifonate lotion, thiabendazole lotion, thiabendazole ointment, dimeticones (NYDA), and a neem seed and coconut oils-based mixture for treatment and coconut oil-based lotion (Zanzarin) for prevention. The coconut oil-based lotion for prevention and dimeticones for treatment of tungiasis have displayed the most promise. Most of the RCTs included in this study had low methodological quality. There is a clear unmet need for high-quality RCTs examining safe and effective prevention and treatment alternatives of tungiasis in endemic settings.

Intensity and clinical morbidities of tungiasis in an impoverished south-west Nigerian community

Sand fleas infestation, Tunga penetrans, remains a neglected tropical disease of public-health concern in many countries. Tungiasis can lead to destruction of the feet causing serious discomfort and deformities. This study aim was to determine the intensity rate and clinical morbidities of tungiasis among the people living in Igbokoda, Ondo State, Nigeria. A community-based cross-sectional survey was conducted among households in three villages in Igbokoda. Hands and feet of selected household members were examined, while fleas on different floor types of houses were sampled by soil collection and extraction by tullgren funnel method. Sand fleas were equally sampled from legs of infested individuals by hand picking. Intensity was determined in terms of number of lesions and fleas in different floor-types. Tungiasis-associated morbidities was assessed using acute and chronic lesions severity scores. The study revealed that moderate infestation was observed in 173 infested individuals and severe infestation in 16 infested individuals. A total of 5293 lesions was observed out of which 3098 were viable. The flea burdens on sampled floors and legs were 127 and 146 fleas respectively occurring mostly in unpaved veranda and rooms (65 and 62 fleas respectively). Tungiasis lesions observed in males were more intense compared to females. Flea lesions and burdens with respect to age stratification and location were significant P < 0.0001. Difficulty in walking, pain upon pressure and deformation of the feet were the most common tungiasis-associated morbidity recorded. Also, tungiasis-associated morbidities, and flea number sampled on legs and on floor of environment were reportedly intense. Therefore, scaling up an appropriate and affordable intervention approach targeted at the fleas would serve as a relief to the scourge of tungiasis in Igbokoda community.

Clinical and macroscopic morphological features of canine tungiasis

Tungiasis is a public health problem in endemic resource-poor communities, where dogs are important reservoirs of Tunga spp., contributing significantly to the process of transmission of this zoonosis. In order to optimize the diagnosis of canine tungiasis, macroscopic morphological characteristics and clinical signs of the lesions were investigated, based on the inspection of 40 dogs infested by T. penetrans from an endemic rural community in northeastern Brazil. Of the 1546 lesions found in these dogs, including all stages of development of the parasite, 89.1% (1378) were located on the paw pads. Dogs aged up to 5 years had the greatest number of lesions. Dark pigmentation and hyperkeratosis of the paw pads made it difficult to identify the lesions. Among all the clinical signs observed were hyperemia (38; 95%), pain (32; 80%), fissure (11; 27.5%), onychogryphosis (29; 72.5%), cluster of lesions (26; 65%), hyperkeratosis (25; 62.5%), lameness (15; 37.5%), and fissure (11; 27.5%). Ectopic lesions were found especially in the nipples (64; 4.1%) and abdomen (51; 3.3%). The maximum diameter of the stage III neosomes was 6 mm. Dogs with a higher number of lesions had a higher degree of hyperkeratosis. Age over 1 year was associated with a higher rate of dispersion of the parasite in the environment (p = 0.04). The identification of the initial stages of tungiasis can guarantee a more effective control of the disease in dogs, which will mainly depend on the treatment of adult animals and the application of continuous preventive actions based on One Health in these communities.

Wolbachia: A tool for livestock ectoparasite control

Ectoparasites and livestock-associated insects are a major concern throughout the world because of their economic and welfare impacts. Effective control is challenging and relies mainly on the use of chemical insecticides and acaricides. Wolbachia, an arthropod and nematode-infecting, maternally-transmitted endosymbiont is currently of widespread interest for use in novel strategies for the control of a range of arthropod-vectored human diseases and plant pests but to date has received only limited consideration for use in the control of diseases of veterinary concern. Here, we review the currently available information on Wolbachia in veterinary ectoparasites and disease vectors, consider the feasibility for use of Wolbachia in the control of livestock pests and diseases and highlight critical issues which need further investigation.

Epidemiology of tungiasis in sub-saharan Africa: a systematic review and meta-analysis

Tungiasis is a public health disease in many rural and urban slums in sub-Saharan Africa (SSA), primarily affecting children and the elderly. Yet, this disease has received little attention in many sub-Saharan African countries. We conducted a systematic review and meta-analysis to estimate the pooled prevalence of tungiasis and associated risk factors in SSA. We searched AJOL, Google Scholar, Web of Science, and PubMed for population-based studies that reported the prevalence of tungiasis and risk factors in SSA between January 1980 and July 2020. The study employed a random-effects model and heterogeneity to estimate the pooled prevalence and evaluate the Cochran's Q-test respectively across studies that met the inclusion criteria. We screened 104 articles and retrieved 42 full-text articles to evaluate for inclusion in the review. Twenty-seven studies involving 16,303 individuals in seven SSA countries were analyzed. The pooled prevalence of tungiasis in SSA was 33.4% (95% CI: 27.6-39.8), while tungiasis prevalence was 46.5%, 44.9%, 42.0%, 37.2%, 28.1%, 22.7% and 20.1% for Ethiopia, Cameroon, Tanzania, Kenya, Nigeria, Rwanda, and Uganda, respectively. The risk of tungiasis was associated with gender, participants' age groups (4-15 years and ≥60 years), earthen floor, non-regular use of footwear, contact with animals, and residence in rural areas. An integrated approach addressing significant factors in tungiasis prevalence in SSA needs to be designed and implemented by a trans-disciplinary composition of community leaders, health professionals, non-governmental institutions, and policymakers.

Parasite-bacteria interrelationship

Parasites and bacteria have co-evolved with humankind, and they interact all the time in a myriad of ways. For example, some bacterial infections result from parasite-dwelling bacteria as in the case of Salmonella infection during schistosomiasis. Other bacteria synergize with parasites in the evolution of human disease as in the case of the interplay between Wolbachia endosymbiont bacteria and filarial nematodes as well as the interaction between Gram-negative bacteria and Schistosoma haematobium in the pathogenesis of urinary bladder cancer. Moreover, secondary bacterial infections may complicate several parasitic diseases such as visceral leishmaniasis and malaria, due to immunosuppression of the host during parasitic infections. Also, bacteria may colonize the parasitic lesions; for example, hydatid cysts and skin lesions of ectoparasites. Remarkably, some parasitic helminths and arthropods exhibit antibacterial activity usually by the release of specific antimicrobial products. Lastly, some parasite-bacteria interactions are induced as when using probiotic bacteria to modulate the outcome of a variety of parasitic infections. In sum, parasite-bacteria interactions involve intricate processes that never cease to intrigue the researchers. However, understanding and exploiting these interactions could have prophylactic and curative potential for infections by both types of pathogens.

Mapping the Geographic Distribution of Tungiasis in Sub-Saharan Africa

The geographic distribution of tungiasis is poorly understood, despite the frequent occurrence of the disease in marginalized populations of low socioeconomic status. To date, little work is available to define the geography of this neglected tropical disease (NTD). This exploratory study incorporated geostatistical modeling to map the suitability for tungiasis transmission in sub-Saharan Africa (SSA). In SSA, environmental suitability is predicted in 44 countries, including Angola, Nigeria, Ghana, Cameroon, Cote de Ivoire, Mali, Ethiopia, the Democratic Republic of the Congo, Kenya, Gabon, Uganda, Rwanda, Tanzania, Zambia, Zimbabwe, Madagascar, and South Africa. In total, an estimated 668 million people live in suitable areas, 46% (304 million) of which reside in East Africa. These evidence-based maps provide vital evidence of the potential geographic extent of SSA. They will help to guide disease control programs, inform policymakers, and raise awareness at the global level. Likewise, these results will hopefully provide decisionmakers with the pertinent information necessary to lessen morbidity and mortality in communities located in environmentally suitable areas.

Efficacy of a mixture of neem seed oil (Azadirachta indica) and coconut oil (Cocos nucifera) for topical treatment of tungiasis. A randomized controlled, proof-of-principle study

Background

Tungiasis is a neglected tropical skin disease caused by the female sand flea (Tunga penetrans), which burrows into the skin causing intense pain, itching and debilitation. People in endemic countries do not have access to an effective and safe home treatment. The aim of this study was to determine the efficacy of a traditionally used and readily available mixture of neem and coconut oil for treatment of tungiasis in coastal Kenya.

Methodology

Ninety-six children aged 6–14 years with at least one embedded viable flea were randomized to be treated with either a mixture of 20% neem (Azadirachta indica) seed oil in coconut oil (NC), or with a 0.05% potassium permanganate (KMnO₄) foot bath. Up to two viable fleas were selected for each participant and monitored for 6 days after first treatment using a digital microscope for signs of viability and abnormal development. Acute pathology was assessed on all areas of the feet using a previously established score. Children reported pain levels and itching on a visual scale.

Results

The NC was not more effective in killing embedded sand fleas within 7 days than the current standard with KMnO₄, killing on average 40% of the embedded sand fleas six days after the initial treatment. However, the NC was superior with respect to the secondary outcomes of abnormal development and reduced pathology. There was a higher odds that fleas rapidly aged in response to NC compared to KMnO₄ (OR 3.4, 95% CI: 1.22–9.49, p = 0.019). NC also reduced acute pathology (p<0.005), and there was a higher odds of children being pain free (OR 3.5, p = 0.001) when treated with NC.

Conclusions

Whilst NC did not kill more fleas than KMnO₄ within 7 days, secondary outcomes were better and suggest that a higher impact might have been observed at a longer observation period. Further trials are warranted to assess optimal mixtures and dosages.

Trial registration

The study was approved by the Kenya Medical Research Institute (KEMRI) Scientific and Ethical Review Unit (SERU), Nairobi (Non-SSC Protocol No. 514, 1st April 2016) and approved by and registered with the Pharmacy and Poisons Board’s Expert Committee on Clinical Trials PPB/ECCT/16/05/03/2016(94), the authority mandated, by Cap 244 Laws of Kenya, to regulate clinical trials in the country. The trial was also registered with the Pan African Clinical Trial Registry (PACTR201901905832601).

Tungiasis is a disease caused by the female sand flea which burrows into the skin of the feet and causes intense pain and itching. People in endemic tropical areas do not have access to a simple, effective and safe method for treatment at home. The most common treatment used during clinical outreach activities is a foot bath in a disinfectant. Here we report on a clinical trial testing the effectiveness of a mixture of neem and coconut oils to kill the embedded fleas and reduce inflammation, pain and itching. We found the oil mixture reduced the proportion of fleas alive in the foot after 6 days in a similar way as the footbath in disinfectant, which is unavailable to households. However, unlike the footbath, the neem oil treatment caused most of the fleas to rapidly age in the foot and decreased the inflammation, leaving more children pain-free after one week. We conclude the neem and coconut oil mixture could be a promising approach for the treatment of tungiasis but its activity on the fleas might be slower. We need to follow up with longer observation time and test different dosages and application times.

Factors associated with tungiasis among primary school children: a cross-sectional study in a rural district in Rwanda

BACKGROUND

Tungiasis is a relatively frequent ectoparasitosis in low-income settings, yet its morbidity and social impact are still not well understood due to the scarcity of information. In Rwanda, data on the magnitude and conditions leading to the tungiasis is rare. This study sought to determine the prevalence and factors associated with tungiasis among primary school children in Rwandan setting.

METHOD

A descriptive cross-sectional study utilising systematic random sampling method was adopted to select 384 children from three primary schools. From July to October 2018, data were collected on socio-demographic characteristics of children, parents, and households. Logistic regression was applied to analyse socio-demographic factors associated with tungiasis with a level of significance set at P-value< 0.05.

RESULTS

Prevalence of tungiasis among three primary schools was 23%. Factors associated with tungiasis included walking barefoot (AOR: 78.41; 95% CI: 17.91-343.10), irregular wearing of shoes (AOR: 24.73; 95% CI: 6.27-97.41), having dirty feet (AOR: 12.69; 95% CI: 4.93-32.64), wearing dirty clothes (AOR: 12.69; 95% CI: 4.18-38.50), and living in a house with earthen plastered floor (AOR: 28.79; 95% CI: 7.11-116.57). Children infected with tungiasis attended class less frequently (AOR: 19.16, 95%CI: 7.20-50.97) and scored lower (AOR: 110.85, 95%CI: 43.08-285.20) than those non-infected. The low school attendance and poor performance could be partly explained by difficulty of walking, lack of concentration during school activities, and isolation or discrimination from classmates.

CONCLUSION

Tungiasis was a public health challenge among school going children in a rural Rwandan setting. This study revealed that children affected with tungiasis had poor hygiene, inadequate housing environments and consequently poor school attendance and performance. Improving socio-economic conditions of households with special emphasis on hygiene of family members and housing conditions, would contribute to preventing tungiasis.

Prevalence, intensity and risk factors of tungiasis in Kilifi County, Kenya II: Results from a school-based observational study

Introduction

Awareness of the public health importance of tungiasis has been growing in East Africa in recent years, but data on epidemiological characteristics necessary for the planning and implementation of control measures do not exist. The work presented here was part of a larger cross-sectional study on the epidemiology of tungiasis in coastal Kenya and aims at identifying risk factors of tungiasis and severe disease in school children.

Methods

A total of 1,829 students of all age groups from five schools and 56 classes were clinically examined for tungiasis on their feet based on standardized procedures and observations made about the school infrastructure. To investigate the impact of school holidays, observations were repeated after school holidays in a subset of children in one school. In an embedded case-control study, structured interviews were conducted with 707 students in the five schools to investigate associations between tungiasis and household infrastructure, behaviour and socio-economic status.

Results

The overall prevalence of tungiasis was 48%; children below the age of 15 years were the most affected, and boys were twice as likely as girls to be infected. The highest risk of disease was associated with the socio-economic circumstances of the individual student at home. The study indicated that mild to moderate tungiasis could be reduced by a third, and severe tungiasis by over half, if sleeping places of children had hardened floors, whilst approximately a seventh of the cases could be prevented by sealing classroom floors in schools, and another fifth by using soap for daily feet washing.

Conclusion

There is a clear role for public health workers to expand the WASH policy to include washing of feet with soap in school-aged children to fight tungiasis and to raise awareness of the importance of sealed floors.

Tungiasis is a neglected tropical skin disease caused by penetrated sand fleas, the adult female of which burrows into the skin of the feet. The parasite rapidly expands its body size by a factor of 2000. The growth causes immense itching, inflammation, pain and debilitation. The current lack of good treatment methods means people attempt to remove the fleas themselves with non-sterile instruments causing more damage. Control efforts focus on prevention but there is little data to guide this in East Africa. The current study reinforces our previously published results on the household level from the same communities, indicating that prevention needs to focus on hardening the floors of resource-poor families and integrating daily foot washing with soap into water, hygiene and sanitation programs.

Spatial distribution, prevalence and potential risk factors of Tungiasis in Vihiga County, Kenya

Background

Tungiasis is a parasitic disease caused by the sand flea Tunga penetrans also known as jigger flea. Communities living in precarious conditions in tropical and sub tropical countries bear the brunt of the infection. The main objective of this study was to determine the burden of Tungiasis in Vihiga County in Kenya.

Methods

This was a cross-sectional study conducted in 21 villages in 3 Sub-locations in Vihiga County, western Kenya. A total of 437 participants, 5 years old and above were clinically examined for the presence of tungiasis after consenting to take part in the study. Diagnosis was made following standard methods. A semi- structured questionnaire was administered to assess socio-demographic factors, housing, presence and ownership of animals, knowledge and practice related to tungiasis. Data were analyzed using bivariate and multivariate regression analysis. GIS was used to map the geographic distribution of tungiasis in the area.

Results

The overall prevalence was found to be (21.5%; 95% CI: 17.7–25.3%). The cases were analysed and visualized in a map form. Multivariate analysis suggested that the occurrence of tungiasis was associated with variables that indicated low economic status (like a monthly income of Ksh ≤ 1000 (adjusted odds ratio 27.85; 95% CI: 4.13–187.59), earthen floor (0.36; 0.13–1.024) and lack of toilet facilities (4.27; 0.82–22.34), age of participant ≤14 (27.414; 10.02–74.99), no regular use of closed footwear (1.98; 0.987–3.97) and common resting place inside the house (1.93; 0.96–3.89).

Conclusions

Tungiasis is an important health problem in Vihiga County occasioned by the low economic status of the people affected. Factors that point to poverty contribute to the occurrence of tungiasis. These findings suggest a need to design control strategies for tungiasis that are cost effective and easily accessible.

Tungiasis even though curable, continues to cause a lot of morbidity and in some cases death to millions of people living in tropical and subtropical countries. The global burden of tungiaisis is not known unlike for most diseases which attract a lot of attention and funding. There are also gaps on the exact geographical distribution of this disease and the communities affected, hence it is largely ignored and neglected by the scientific community, the health sector, pharmaceutical industries and policy makers. As a consequence, there are no universally accepted methods to treat and control tungiasis. The study attempted to close this gap by combining geographic information system and questionnaire data to visualize the burden and risk factors of tungiasis in Vihiga County, Kenya. The researchers found that tungiasis is an important health burden in Vihiga County, Kenya and that its occurrence was associated with factors that point to poverty. These findings suggest a need to design control strategies for tungiasis that are cost effective and easily accessible by the communities affected.

Very severe tungiasis in Amerindians in the Amazon lowland of Colombia: A case series

Background

Tungiasis is a parasitic skin disease caused by penetrating female sand fleas. By nature, tungiasis is a self-limiting infection. However, in endemic settings re-infection is the rule and parasite load gradually accumulates over time. Intensity of infection and degree of morbidity are closely related.

Methodology/principal findings

This case series describes the medical history, the clinical pathology, the socio-economic and the environmental characteristics of very severe tungiasis in five patients living in traditional Amerindian communities in the Amazon lowland of Colombia. Patients had between 400 and 1,300 penetrated sand fleas. The feet were predominantly affected, but clusters of embedded sand fleas also occurred at the ankles, the knees, the elbows, the hands, the fingers and around the anus. The patients were partially or totally immobile. Patients 1 and 3 were cachectic, patient 2 presented severe malnutrition. Patient 3 needed a blood transfusion due to severe anemia. All patients showed a characteristic pattern of pre-existing medical conditions and culture-dependent behavior facilitating continuous re-infection. In all cases intradomiciliary transmission was very likely.

Conclusion/significance

Although completely ignored in the literature, very severe tungiasis occurs in settings where patients do not have access to health care and are stricken in a web of pre-existing illness, poverty and neglect. If not treated, very severe tungiasis may end in a fatal disease course.

Tungiasis (also called sand flea disease) is a neglected tropical disease (NTD) caused by the penetration of female sand fleas in the skin, typically at the toes, the sole or the heel. Once embedded in the upper strata of the skin, the parasite hypertrophies, enlarging its body size by a factor of 2000 within ten days. This causes intense inflammation with pain and itching, eventually leading to impaired mobility. During a period of three weeks, eggs are expelled through a tiny opening in the skin. When the last egg has been released into the environment, the parasite shrinks and eventually dies. Hence, by nature tungiasis is a self-limited infection. However, in endemic settings re-infection is the rule and parasite load gradually accumulates over time. Here we report five cases with extremely severe tungiasis in patients with 400 to 1,300 embedded sand fleas. Not only the feet were affected, but clusters of parasites also occurred at the ankles, the knees, the elbows, the hand, the fingers and around the anus. The patients were partially or totally immobile. Two patients were cachectic and one required a blood transfusion. All patients showed a characteristic pattern of pre-existing medical conditions and culture-related behaviour facilitating continuous re-infection.

Prevalence and risk factors of tungiasis among children of Wensho district, southern Ethiopia

Background

Tungiasis is an ectoparasitic infestation, which still has public health importance in deprived populations of developing countries. Data on the prevalence and risk factors of tungiasis is rare in Ethiopia. Hence, this study was designed to determine the prevalence and risk factors of tungiasis among children in Wensho district, southern Ethiopia.

Methods

From February to May 2016, we conducted a community-based cross-sectional study on 366 children 5–14 years old. Data about the presence and severity of tungiasis were obtained through inspection and data on risk factors were collected through interviews of parents/guardians of the children using structured questionnaire and through observation of the housing environment using structured checklist.

Results

Two hundred fifteen (58.7%, 95% confidence interval [CI]: 53.7%, 63.8%) of the 366 children were infested with Tunga penetrans. Most lesions were localized in the feet and the distribution of the disease by sex was similar (57.4% among males and 60.3% among females). Children of illiterate mothers (adjusted odds ratio [AOR]: 3.62, 95% CI: 1.35, 9.73) and children whose mothers have attended only primary education (AOR: 2.72, 95% CI: 1.06, 6.97), children from cat owning households (AOR: 4.95, 95% CI: 1.19, 20.60) and children who occasionally use footwear (AOR: 7.42, 95% CI: 4.29, 12.83) and those who never use footwear (AOR: 12.55, 95% CI: 3.38, 46.58) had a significantly higher odds of tungiasis infestation.

Conclusion

Tungiasis is an important public health problem with considerable morbidity among children in Wensho. Hence, implementation of tungiasis prevention strategies such as promoting shoes wearing, provision of health education, fumigating the residential houses and applying insecticides on pets are recommended.

Tungiasis-related life quality impairment in children living in rural Kenya

BACKGROUND

Tungiasis (sand flea disease) is a neglected tropical skin disease caused by female sand fleas (Tunga spp.) embedded in the skin of the host. The disease is common in sub-Saharan Africa and predominantly affects children living in impoverished rural communities. In these settings tungiasis is associated with important morbidity. Whether tungiasis impairs life quality has never been studied.

METHODS

The study was performed in 50 children with tungiasis, living in resource-poor communities in coastal Kenya. Based on the Dermatology Life Quality Index (DLQI) a tool was developed to determine life quality impairment associated with tungiasis in children, the tungiasis-related Dermatology of Life Quality Index (tungiasis-related-DLQI). Pain and itching were assessed using visual scales ranging from 0-3 points. The intensity of infection and the acute and chronic severity of tungiasis were determined using standard methods.

RESULTS

Seventy eight percent of the patients reported a moderate to very large effect of tungiasis on life quality at the time of the diagnosis. The degree of impairment correlated with the number of viable sand fleas present in the skin (rho = 0.64, p < 0.001), the severity score of acute clinical pathology (rho = 0.74, p < 0.001), and the intensity of pain (rho = 0.82, p < 0.001). Disturbance of sleep and concentration difficulties were the most frequent restriction categories (86% and 84%, respectively). Four weeks after curative treatment, life quality had improved significantly. On the individual level the amelioration of life quality correlated closely with the regression of clinical pathology (rho = 0.61, p < 0.001).

CONCLUSION

The parasitic skin disease tungiasis considerably impairs life quality in children in rural Kenya. After effective treatment, life quality improves rapidly.

Animal and human tungiasis-related knowledge and treatment practices among animal keeping households in Bugiri District, South-Eastern Uganda

BACKGROUND

Zoonotic tungiasis caused by Tunga penetrans remains a serious public and animal health problem among endemic villages in Uganda and many sub Saharan African countries. Studies on human and animal tungiasis-related knowledge and treatment practices in endemic communities have never been undertaken, a limitation to development of sustainable control measures.

METHODS

A cross sectional study using semi-structured questionnaires (Supplementary file S1) was conducted among 236 animal rearing households in 10 endemic villages in Bugiri District, South-Eastern Uganda. Focus group discussions and observation checklists were used to validate and clarify the findings.

RESULTS

Most respondents knew the aetiology (89.4%), clinical signs (98%) and the ecology of T. penetrans as well as the major risk factors of human tungiasis (65.2%). In contrast, very few respondents were aware of animal tungiasis. Only 4.8% of those with infected animals on the compound knew that some of their animals were infected and 13.6% of the respondents had ever seen tungiasis-affected animals. Pigs (13.1%, n=31) and dogs (0.85%, n=2) were the only T. penetrans animal hosts known to animal owners. Affected humans were treated by extraction of embedded sand fleas using non-sterile sharp instruments in all households that reported occurrence of human tungiasis at least once (n=227). Also, affected animals were mainly treated by mechanical removal of embedded sand fleas in households that have ever experienced animal tungiasis (four out of 12; 33.3%). In a few instances, plant and animal pesticides (n=3) and other chemicals such as grease, paraffin and wood preservative (n=3) were also used to treat animal tungiasis.

CONCLUSION

The study revealed a high level of knowledge on human tungiasis but inadequate knowledge on the zoonotic nature of tungiasis. Commonly applied methods for treatment of human and animal tungiasis are a health hazard by themselves. Concerted i.e. One Health-based efforts aiming at promoting appropriate treatment of tungiasis, adequate living conditions and increased awareness on tungiasis in the communities are indicated in order to eliminate tungiasis-associated disease.

Tungiasis. A Case of Diagnosis of Tropical Dermatosis

A case of tungiasis is presented — infestation with Tunga penetrans of a man who was on vacation in Peru, with eruptions localized on toes I and V of the both feet. For treatment of the patient, the parasites were surgically removed out of the lesions, whereupon the lesions were treated with antiseptics.

Prevalence, intensity and risk factors of tungiasis in Kilifi County, Kenya: I. Results from a community-based study

BACKGROUND

Tungiasis is a neglected tropical disease caused by female sand fleas (Tunga penetrans) embedded in the skin. The disease is associated with important morbidity. Tungiasis is endemic along the Coast of Kenya with a prevalence ranging from 11% to 50% in school-age children. Hitherto, studies on epidemiological characteristics of tungiasis in Africa are scanty.

METHODS

In a cross-sectional study 1,086 individuals from 233 households in eight villages located in Kakuyuni and Malanga Sub-locations, Kilifi County, on the Kenyan Coast, were investigated. Study participants were examined systematically and the presence and severity of tungiasis were determined using standard methods. Demographic, socio-economic, environmental and behavioral risk factors of tungiasis were assessed using a structured questionnaire. Data were analyzed using bivariate and multivariate regression analysis.

RESULTS

The overall prevalence of tungiasis was 25.0% (95% CI 22.4-27.5%). Age-specific prevalence followed an S-shaped curve, peaking in the under-15 year old group. In 42.5% of the households at least one individual had tungiasis. 15.1% of patients were severely infected (≥ 30 lesions). In the bivariate analysis no specific animal species was identified as a risk factor for tungiasis. Multivariate analysis showed that the occurrence of tungiasis was related to living in a house with poor construction characteristics, such as mud walls (OR 3.35; 95% CI 1.71-6.58), sleeping directly on the floor (OR 1.68; 95% CI 1.03-2.74), the number of people per sleeping room (OR = 1.77; 95% CI 1.07-2.93) and washing the body without soap (OR = 7.36; 95% CI 3.08-17.62). The odds of having severe tungiasis were high in males (OR 2.29; 95% CI 1.18-44.6) and were very high when only mud puddles were available as a water source and lack of water permitted washing only once a day (OR 25.48 (95% CI 3.50-185.67) and OR 2.23 (95% CI 1.11-4.51), respectively).

CONCLUSIONS

The results of this study show that in rural Kenya characteristics of poverty determine the occurrence and the severity of tungiasis. Intra-domiciliary transmission seems to occur regularly.

High-resolution infrared thermography: a new tool to assess tungiasis-associated inflammation of the skin

BACKGROUND

Tungiasis is highly prevalent in low- and middle-income countries but remains often under diagnosed and untreated eventually leading to chronic sequels. The objective of the study was to assess whether tungiasis-associated inflammation can be detected and quantified by high-resolution infrared thermography (HRIT) and whether after removal of the parasite inflammation resolves rapidly.

METHODS

Patients with tungiasis were identified through active case finding. Clinical examination, staging, and thermal imaging as well as conventional photography were performed. In exemplary cases, the embedded sandfly was extracted and regression of inflammation was assessed by thermal imaging 4 days after extraction.

RESULTS

The median perilesional temperature was significantly higher than the median temperature of the affected foot (rho = 0.480, p = 0.003). Median perilesional temperature measured by high-resolution infrared thermography was positively associated with the degree of pain (rho = 0.395, p < 0.017) and semi-quantitative scores for acute (rho = 0.380, p < 0.022) and chronic (rho = 0.337, p < 0.044) clinical pathology. Four days after surgical extraction, inflammation and hyperthermia of the affected area regressed significantly (rho = 0.457, p = 0.005). In single cases, when clinical examination was difficult, lesions were identified through HRIT.

CONCLUSION

We proved that HRIT is a useful tool to assess tungiasis-associated morbidity as well as regression of clinical pathology after treatment. Additionally, HRIT might help to diagnose hidden and atypical manifestations of tungiasis. Our findings, although still preliminary, suggest that HRIT could be used for a range of infectious skin diseases prevalent in the tropics.

TRIAL REGISTRATION

ISRCTN11415557, Registration date: 13 July 2011.

Secondary bacterial infections and antibiotic resistance among tungiasis patients in Western, Kenya

Tungiasis or jigger infestation is a parasitic disease caused by the female sand flea Tunga penetrans. Secondary infection of the lesions caused by this flea is common in endemic communities. This study sought to shed light on the bacterial pathogens causing secondary infections in tungiasis lesions and their susceptibility profiles to commonly prescribed antibiotics. Participants were recruited with the help of Community Health Workers. Swabs were taken from lesions which showed signs of secondary infection. Identification of suspected bacteria colonies was done by colony morphology, Gram staining, and biochemical tests. The Kirby Bauer disc diffusion test was used to determine the drug susceptibility profiles. Out of 37 participants, from whom swabs were collected, specimen were positive in 29 and 8 had no growth. From these, 10 different strains of bacteria were isolated. Two were Gram positive bacteria and they were, Staphylococcus epidermidis (38.3%) and Staphylococcus aureus (21.3%). Eight were Gram negative namely Enterobacter cloacae (8.5%), Proteus species (8.5%), Klebsiellla species (6.4%), Aeromonas sobria (4.3%), Citrobacter species (4.3%), Proteus mirabillis(4.3%), Enterobacter amnigenus (2.1%) and Klebsiella pneumoniae (2.1%). The methicillin resistant S. aureus (MRSA) isolated were also resistant to clindamycin, kanamycin, erythromycin, nalidixic acid, trimethorprim sulfamethoxazole and tetracycline. All the Gram negative and Gram positive bacteria isolates were sensitive to gentamicin and norfloxacin drugs. Results from this study confirms the presence of resistant bacteria in tungiasis lesions hence highlighting the significance of secondary infection of the lesions in endemic communties. This therefore suggests that antimicrobial susceptibility testing may be considered to guide in identification of appropriate antibiotics and treatment therapy among tungiasis patients.

Control of Tungiasis in Absence of a Roadmap: Grassroots and Global Approaches

Tungiasis is a tropical skin disease caused by the sand flea Tunga penetrans. It inflicts misery upon tens of millions of people, mostly children, across Central and South America and sub-Saharan Africa, and yet there is no globally accepted roadmap for its control. Here we review how research in the last 15 years has developed control methods and report on new grassroots and digital mapping approaches. Treatment is now possible with a two-component dimethicone, used for the treatment of headlice in Europe, Asia and Canada, but not yet available in most tungiasis-endemic areas. Prevention is possible through the daily use of repellents based on coconut oil. A Kenyan coastal community has successfully controlled tungiasis using a neem and coconut oil mix produced locally to treat cases, combined with spraying floors with neem solution and distributing closed shoes. Development of affordable hard floor technology is underway, although not yet widely available, but is a priority to control off-host stages in the floors of homes. A new web-based digital mapping application will enable researchers and health officials to collaborate, share data and map the prevalence of tungiasis. We conclude that tungiasis can be controlled through a multi-disciplinary, One Health approach.

Treatment of tungiasis with a two-component dimeticone: a comparison between moistening the whole foot and directly targeting the embedded sand fleas

BACKGROUND

Tungiasis (sand flea disease) is caused by the penetration of female sand fleas (Tunga penetrans, Siphonaptera) into the skin. It belongs to the neglected tropical diseases and is prevalent in South America, the Caribbean and sub-Saharan Africa. Tungiasis predominantly affects marginalized populations and resource-poor communities in both urban and rural areas. In the endemic areas, patients do not have access to an effective and safe treatment. A proof-of-principle study in rural Kenya has shown that the application of a two-component dimeticone (NYDA®) which is a mixture of two low viscosity silicone oils caused almost 80% of the embedded sand fleas to lose their viability within 7 days.

METHODS

In this study we compared the efficacy of two distinct modes of application of NYDA®; one targeted application to the area where the parasite protrudes through the skin and one comprehensive application to the whole foot.

RESULTS

Independent of the two modes of application, the dimeticone caused more than 95% of embedded sand fleas to lose all signs of viability within 7 days. The targeted application killed embedded sand fleas more rapidly compared to when the whole foot was covered. The proportion of viable lesions at day two were 7.0 versus 23.4% (p < 0.01) and at day five 3.9 versus 12.5% (p < 0.02).

CONCLUSIONS

Our findings suggest that the dimeticone could provide a safe and effective treatment for tungiasis in areas with difficult access to health care.

TRIAL REGISTRATION

ISRCTN ISRCTN74306878.

Disseminated tungiasis in a 78-year-old woman from Tanzania: a case report

Background

Tungiasis is one of the neglected tropical diseases; it affects up to 40% of individuals living in societies with poor housing and sanitation standards. In endemic areas, Tunga infestation, which predominantly affects the periungual areas of the lower limbs in humans, is associated with considerable morbidity and poor quality of life.

Case presentation

A 78-year-old woman of African descent presented with pain, inflammation, suppuration, ulceration, and deformation of digits of all four limbs. She had a total of 1146 embedded sand fleas: 812 in lower limbs and 334 in her hands. She was febrile; her full blood count revealed pancytopenia and blood cultures were positive for Staphylococcus aureus and Streptococcus pyogenes isolates. Furthermore, she had severe hyponatremia. We applied 20% salicylated petroleum jelly followed by the manual removal of embedded sand fleas with a sterile needle. Intravenously administered piperacillin-tazobactam, topical ivermectin, ferrous sulfate, folic acid, tolvaptan, albendazole, multivitamins, and tetanus prophylaxis were instituted. She was discharged home after 16 days of hospitalization.

Conclusions

Tungiasis is a neglected disease of concern in underprivileged societies that is preventable and curable. Early recognition and prompt treatment is crucial to prevent complications in this disease which may potentially mimic other conditions resulting in erroneous management.

Successful Treatment of Severe Tungiasis in Pigs Using a Topical Aerosol Containing Chlorfenvinphos, Dichlorphos and Gentian Violet

Background

In endemic communities, zoonotic tungiasis, a severe skin disease caused by penetrating female sand fleas, is a public health hazard causing significant human and animal morbidity. No validated drugs are currently available for treatment of animal tungiasis. Due to the reservoir in domestic animals, integrated management of human and animal tungiasis is required to avert its negative effects.

Methods and principal findings

A topical aerosol containing chlorfenvinphos 4.8%, dichlorphos 0.75% and gentian violet 0.145% licensed to treat tick infestations, myiasis and wound sepsis in animals in the study area, was tested for its potential tungicidal effects in a randomized controlled field trial against pig tungiasis in rural Uganda. Animals with at least one embedded flea were randomized in a treatment (n = 29) and a control (n = 26) group. One week after treatment, 58.6% of the treated pigs did not show any viable flea lesion whereas all control pigs had at least one viable lesion. After treatment the number of viable lesions (treated median = 0, overall range = 0–18 vs. control median = 11.5, range = 1–180) and the severity score for estimating acute pathology in pig tungiasis (treated median = 1, range = 0–3.5 vs. control median = 7, range = 0–25) were significantly lower in treated than in control pigs (p < 0.001). In the treatment group the median number of viable flea lesions decreased from 8.5 to 0 (p < 0.001). Similarly, the median acute severity score dropped from 6 to 1 (p < 0.001). Every pig in the treatment group showed a decrease in the number of viable fleas and tungiasis-associated acute morbidity while medians for both increased in the control group.

Conclusions

The study demonstrates that a topical treatment based on chlorfenvinphos, dichlorphos and gentian violet is highly effective against pig tungiasis. Due to its simplicity, the new approach can be used for the treatment of individual animals as well as in mass campaigns.

Infection with the sand flea Tunga penetrans causes severe disease in humans and animals. There are no validated drugs for treatment of animal tungiasis preventing implementation of integrated tungiasis control interventions targeting human and animal infections. A field trial was conducted to evaluate the effects of a commercial insecticidal aerosol containing chlorfenvinphos 4.8%, dichlorphos 0.75%, and gentian violet 0.145%, which is licensed to treat tick infestations, myiasis and wound sepsis, on tungiasis in pigs, the major animal reservoir in rural hyperendemic villages in Uganda. Infected pigs were recruited and randomly assigned to treatment (n = 29) and control (n = 26) groups. Seven days after a single application of the aerosol onto the affected body parts, almost 60% of the treated pigs were cured while all control pigs had at least one penetrated sand flea. The number of viable sand fleas and the severity of the tungiasis were significantly lower in the treated pigs than in the controls. This demonstrates for the first time that a simple and effective topical treatment for animal tungiasis based on two organophosphate insecticides and an antibacterial agent can be used to cure individual animals and can be integrated in tungiasis control campaigns.

Animal Reservoirs of Zoonotic Tungiasis in Endemic Rural Villages of Uganda

BACKGROUND

Animal tungiasis is believed to increase the prevalence and parasite burden in humans. Animal reservoirs of Tunga penetrans differ among endemic areas and their role in the epidemiology of tungiasis had never been investigated in Uganda.

METHODS AND FINDINGS

To identify the major animal reservoirs of Tunga penetrans and their relative importance in the transmission of tungiasis in Uganda, a cross sectional study was conducted in animal rearing households in 10 endemic villages in Bugiri District. T. penetrans infections were detected in pigs, dogs, goats and a cat. The prevalences of households with tungiasis ranged from 0% to 71.4% (median 22.2) for animals and from 5 to 71.4% (median 27.8%) for humans. The prevalence of human tungiasis also varied among the population of the villages (median 7%, range 1.3-37.3%). Pig infections had the widest distribution (nine out of 10 villages) and highest prevalence (median 16.2%, range 0-64.1%). Pigs also had a higher number of embedded sand fleas than all other species combined (p < 0.0001). Dog tungiasis occurred in five out of 10 villages with low prevalences (median of 2%, range 0-26.9%). Only two goats and a single cat had tungiasis. Prevalences of animal and human tungiasis correlated at both village (rho = 0.89, p = 0.0005) and household (rho = 0.4, p < 0.0001) levels. The median number of lesions in household animals correlated with the median intensity of infection in children three to eight years of age (rho = 0.47, p < 0.0001). Animal tungiasis increased the odds of occurrence of human cases in households six fold (OR = 6.1, 95% CI 3.3-11.4, p < 0.0001).

CONCLUSION

Animal and human tungiasis were closely associated and pigs were identified as the most important animal hosts of T. penetrans. Effective tungiasis control should follow One Health principles and integrate ectoparasites control in animals.

Characterization of Tunga penetrans antigens in selected epidemic areas in Murang'a county in Kenya

Tunga penetrans are fleas that cause tungiasis, a condition characterized by high transmission rate due to poor housing conditions, social neglect and inadequate health care in economically disadvantaged communities in developing countries. This study therefore aimed at characterizing jiggers antigens to identify immunodominant ones to help understand immunological behavior of the parasite that would otherwise be important in future control of the parasite. Samples were gravid fleas and blood samples from infested individuals in Kahuro and Murang'a East district in Murang'a County. Freeze and thaw was used to extract soluble proteins from the fleas. Ouchterlony Double immunodiffusion was used to assess antigen-antibody reactions between extracted soluble protein and the serum from immunized rats, Rattus norvegicus prior to analysis of human sera. These results were comparable to results of immunoelectrphoresis. Jigger protein isolates were analyzed in Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis technique (SDS-PAGE), against Pharmacia standard protein markers. Further analysis of jigger antigens against pooled human sera from infested victims in Western blot revealed three immunodominant antigens. Using simple regression analysis molecular weights of the three immunodominant antigens were estimated as 51.795, 23.395 and 15.38 kDa respectively. These results are important since they would help understand immunological behavior of the parasites. This would help to create basis for designing and improving approaches against jiggers such as development of immune prophylaxis to complement social science approaches that is mainly concerned with maintenance of high standards of hygiene.

Treatment of parasitic skin diseases with dimeticones a new family of compounds with a purely physical mode of action

Epidermal parasitic skin diseases (EPSD) are common in the tropics and sub-tropics. They are caused by mites, lice and other blood-sucking insects. In resource-poor countries they are associated with considerable morbidity. Hitherto, EPSD are treated with insecticides with a neurotoxic mode of action. The efficacy of this treatment is variable, and the development and spread of resistant mites and lice is alarming. A new concept for treating EPSD is presented which is based on the topical application of dimeticones, silicone oils of low viscosity which rapidly kill insects and mites by a physical mode of action. They creep into the respiratory system and block oxygen supply. The physical mode of action makes the development of resistant parasite strains very unlikely. Due to their safety and efficacy, dimeticones are promising candidates for population-based intervention programmes targeted against EPSD in resource-poor settings.

Treatment of Tungiasis with dimeticone: a proof-of-principle study in rural Kenya

Tungiasis (sand flea disease) is a neglected tropical disease, prevalent in resource-poor communities in South America and sub-Saharan Africa. It is caused by an inflammatory response against penetrated female sand fleas (Tunga penetrans) embedded in the skin of the host. Although associated with debilitating acute and chronic morbidity, there is no proven effective drug treatment. By consequence patients attempt to remove embedded sand fleas with non-sterile sharp instruments, such as safety pins, a procedure that represents a health threat by itself. In this proof-of-principle study we compared the topical application of a mixture of two dimeticones of low viscosity (NYDA) to the topical application of a 0.05% solution of KMnO4 in 47 school children in an endemic area in rural Kenya. The efficacy of the treatment was assessed during a follow up period of seven days using viability signs of the embedded parasites, alterations in the natural development of lesion morphology and the degree of local inflammation as outcome measures. Seven days after treatment, in the dimeticone group 78% (95% CI 67–86%) of the parasites had lost all signs of viability as compared to 39% (95% CI 28–52%) in the KMnO4 group (p<0.001). In the dimeticone group 90% (95% CI 80–95%) of the penetrated sand fleas showed an abnormal development already after 5 days, compared to 53% (95% CI 40–66%; p<0.001) in the KMnO4 group. Seven days after treatment, signs of local skin inflammation had significantly decreased in the dimeticone group (p<0.001). This study identified the topical application of dimeticones of low viscosity (NYDA) as an effective means to kill embedded sand fleas. In view of the efficacy and safety of the topical treatment with dimeticone, the mechanical extraction of embedded sand fleas using hazardous instruments is no longer warranted.

Tungiasis (sand flea disease), a parasitic skin disease, causes important morbidity, and eventually leads to mutilation of the feet. Hitherto, the only effective treatment is the surgical extraction of embedded sand fleas. In the endemic areas this is done using inappropriate sharp instruments and causes more harm than good. We identified the three last abdominal segments of Tunga penetrans which protrude through the skin and through which the parasite breathes, defecates, and expels eggs - as an Achilles heel of embedded sand fleas. In a proof-of-principle study we investigated whether this Achilles heel is vulnerable to dimeticone with a low viscosity and a high creeping property. We randomized the left and the right feet to either receive a topical application of KMnO4 (the standard treatment in Kenya) or of dimeticone. The major outcome measure was the absence of viability signs of the treated sand fleas. The study shows that the topical application of a mixture of two dimeticones (NYDA) effectively kills embedded sand fleas within seven days. Since dimeticones are considered to be wholly non-toxic and are not expensive the new treatment could become a means to control tungiasis-associated morbidity on the population level.

Tungiasis in Haiti: a case series of 383 patients

BACKGROUND

Tungiasis is endemic in poverty-stricken communities of South and Central America, Africa, Asia, and the Caribbean. This ectoparasitosis, caused by the female sand flea Tunga penetrans, is associated with considerable longterm morbidity in severely affected patients, including toe deformation and limited mobility. In Haiti, tungiasis is poorly documented but is known to occur. This study is the first formal investigation of tungiasis in Haiti.

METHODS

A total of 383 patients in four regions (Belle Fontaine, Vallue, Savanette, Cerca Carvajal) were examined and interviewed to determine disease prevalence, demographics and clinical presentation, and tungiasis-related behaviors.

RESULTS

Prevalences of tungiasis ranged from 10.6 to 81.8% across the four regions. The overall prevalence of tungiasis in the patients examined was 31.1%. Of the affected patients, 63% were male and 37% were female, 37% were aged 0-10 years, and 100% reported pain and pruritus. Lesions occurred on the feet in 93.3% and on the hands in 22.7% of affected patients. The most common complications observed were chronic inflammation (54.2%) and hyperkeratosis (48.2%).

CONCLUSIONS

This study establishes tungiasis as endemic in four regions of Haiti and reveals disease characteristics similar to those reported previously, suggesting that there are common factors underlying this disease in various regions, which are likely to be poverty-related. These findings emphasize the need to acknowledge tungiasis as a clinically relevant public health issue in order to decrease the frequency of tungiasis-related morbidity in endemic areas.

Revision on tungiasis: treatment options and prevention

The parasitic skin disease tungiasis occurs in many resource-poor communities in Latin America, the Caribbean and sub-Saharan Africa. The sand flea, Tunga penetrans, most commonly penetrates into the skin of the feet. Many individuals harbor a large number of embedded parasites and show significant morbidity. Standard treatment consists of surgical extraction of the flea and application of a topical antibiotic. There are no drugs available with proven effectiveness. Clinical trials performed in the last few years did not show very promising results. Thus, surgical extraction still remains the treatment of choice in patients with a low parasite load, such as tourists returning from endemic areas. Probably the best approach to reduce tungiasis-associated morbidity in heavily affected individuals is the application of a repellent to prevent the penetration of sand fleas. In the future, we should see new exciting data on the biology, epidemiology, therapy and control of tungiasis.

Topical treatment of tungiasis: a randomized, controlled trial

Tungiasis is caused by the penetration of the female sand flea Tunga penetrans into the epidermis of its host. Human infestation with this ectoparasite is hyper-endemic in many resource-poor communities in sub-Saharan Africa, the Caribbean and South America and is associated with considerable morbidity. Currently, there is no effective drug available to treat tungiasis (or at least none for which a parasiticidal effect has been clearly demonstrated). In an attempt to fill this gap, the effects of treatment with topical ivermectin (lotion), thiabendazole (ointment and lotion), metrifonate (lotion) or placebo lotion were compared in a randomized trial. A total of 108 subjects with 169 tungiasis-infested feet participated in the study. The results show that topical ivermectin, metrifonate or thiabendazole can each significantly reduce the number of lesions caused by embedded sand fleas. Further studies are needed to optimise the doses and administration of these compounds.

Tungiasis - A Janus-faced parasitic skin disease

Tungiasis is a parasitic skin disease caused by the penetration of female sand fleas (Tunga penetrans). It is acquired when people walk barefoot or rest on soil, where sand fleas have completed the off-host cycle. Tungiasis is a classic poverty-associated disease which belongs to the family of neglected tropical diseases (NTD). It has a Janus-face: while in travellers tungiasis usually is a benign self-limiting skin disease, inhabitants of endemic areas suffer from heavy infestations and severe, frequently debilitating and incapacitating morbidity. We describe the epidemiological and clinical characteristics of travel-associated tungiasis and compare these features to the situation in resource-poor communities in South America and sub-Saharan Africa.