A plant-based repellent protects against Tunga penetrans infestation and sand flea disease

Aloe vera-An Extensive Review Focused on Recent Studies

Since ancient times, Aloe vera L. (AV) has attracted scientific interest because of its multiple cosmetic and medicinal properties, attributable to compounds present in leaves and other parts of the plant. The collected literature data show that AV and its products have a beneficial influence on human health, both by topical and oral use, as juice or an extract. Several scientific studies demonstrated the numerous biological activities of AV, including, for instance, antiviral, antimicrobial, antitumor, and antifungal. Moreover, its important antidepressant activity in relation to several diseases, including skin disorders (psoriasis, acne, and so on) and prediabetes, is a growing field of research. This comprehensive review intends to present the most significant and recent studies regarding the plethora of AV's biological activities and an in-depth analysis exploring the component/s responsible for them. Moreover, its morphology and chemical composition are described, along with some studies regarding the single components of AV available in commerce. Finally, valorization studies and a discussion about the metabolism and toxicological aspects of this "Wonder Plant" are reported.

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.

Evaluating the potentials of randomised integrated control trial on tungiasis in a South-western Nigerian community

Considering the fact that new, safe and incorporable treatment alternatives to therapeutic prophylaxis for tungiasis are lacking and sometimes proving difficult, this present study evaluated the potentials of integrating control approach involving focal premise treatment using 5% emulsifiable concentrate of cypermethrin, and topical application of Piper guineense oil with personal protection. Of the 90 houses selected, their floors were classified into paved rooms & unpaved verandas, paved verandas & unpaved rooms, paved rooms & verandas, and unpaved rooms & verandas, and tested for the presence of sand fleas using the sweeping and beating as well as soil collection and extraction by tullgren funnel method before fumigation. A total of 100 individuals partitioned into four groups of 25 individuals each were assigned 3%, 5%, 10% and 15% of P. guineense oil irrespective of stages of embedded fleas. The mean of sand fleas decreased from 1.14, 0.07, 0.21, and 1.66 to 0.37, 0.02, 0.09 and 1.08 after two weeks of single spray compared to the untreated location (p <  0.001). Furthermore, the mean lesions of stage I reduced to 0 after 2 to 6 days of 3%, 5%, 10% and 15% ointment application, and stage II and III after 10 to 12 days of 10% and 15% application respectively. The difference between tungiasis stages and exposure time for P. guineense ointment was highly significant p = 0.007 and p = 0.0002. Notable reduction in severity score of acute and chronic tungiasis was observed thus indicating effectiveness of the topical ointment. Hexanolic oil extracts of P. guineense in 10% and 15% concentration would kill embedded sand flea and ameliorate the sufferings in endemic settings.

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.

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.

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.

Tungiasis, a rare case of plantar inflammatory disease, a review of travelers skin lesions for emergency providers

Parasitic infections while common in underdeveloped nations are rarely seen in developed urban centers. We report a case of a thirty-three-year-old male with no past medical history who presented to the emergency department with a chief complaint of "eggs coming out of my foot" after returning home from Brazil. Based on clinical presentation, travel history, and appearance of the lesion, diagnosis was most consistent with tungiasis infection which was confirmed by the pathology examination. It is important to make the appropriate diagnosis when skin lesions are found in returning travelers and emergency providers should take broad differential diagnosis into consideration.

Tungiasis: Outbreak investigation of a zoonosis during overseas deployment

Background

Tungiasis is an ectoparasitosis caused by the sand flea Tunga penetrans. It is endemic in the under privileged communities of Latin America, the Caribbean and Sub Saharan Africa with geographic and seasonal variations even within endemic areas. We describe investigation of an outbreak of Tungiasis in troops deployed as part of UN peacekeeping force in Central Africa.

Methods

Tungiasis was diagnosed in an unusually large number of cases of severely pruritic boils over feet in soldiers of a UN peacekeeping battalion. An outbreak investigation was carried out and the outbreak was described in time, place and person distribution. A retrospective cohort study was done to ascertain the associated risk factors.

Results

A total of 36 cases were identified of which 33 had laboratory confirmation. Of the 36 cases, 10(27.77%) had only Fortaleza Stage II lesions, 22 (61.11%) a combination of Fortaleza Stage II and III lesions and four (11.11%) cases had a combination of Stage, II, III and IV lesions. Secondary bacterial infection was seen in 25 (69.44%) cases. Epidemiological analysis revealed that it was a common source single exposure outbreak traced to a temporary campsite along one of the patrolling routes.

Conclusion

In a Military setting an integrated approach combining health education and environmental control is required to prevent such outbreaks.

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.

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.

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.

An improved bioassay facilitates the screening of repellents against cat flea, Ctenocephalides felis (Siphonaptera: Pulicidae)

BACKGROUND

Repellents are a common method for preventing flea bites, making an effective system for flea repellent screening advantageous. We describe an improved technique to facilitate repellent activity screening of numerous plant-based Ctenocephalides felis (cat flea) repellents.

RESULTS

Two long strips of filter paper were impregnated with test compounds (dissolved in ethanol) and ethanol only, respectively. After drying, the two filter papers were glued together along the long side and inserted into a glass tube containing non-fed cat fleas. The distribution of cat fleas in each half of the filter paper was recorded after 30 min to calculate repellency. Results showed that the essential oil of Cinnamomum osmophloeum (from leaf), Taiwania cryptomerioides (from heartwood) and Plectranthus amboinicus (from leaf) exhibits repellent activity against cat fleas in a dose dependent manner. Moreover, the repellent activities against cat fleas of 2% trans-cinnamaldehyde (the main constituent of Ci. osmophloeum essential oil) and 0.5% thymol (the main constituent of P. amboinicus essential oil) are 97.6% and 90.6%, and can persist for up to 4 and 8 h, respectively. These results are comparable to those of 15% DEET.

CONCLUSION

The proposed screening technique can facilitate the pre-screening of numerous flea repellents for further evaluation on animal or human subjects.

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.

Prevention of tungiasis and tungiasis-associated morbidity using the plant-based repellent Zanzarin: a randomized, controlled field study in rural Madagascar

Background

Tungiasis, a parasitic skin disease caused by the female sand flea Tunga penetrans, is a prevalent condition in impoverished communities in the tropics. In this setting, the ectoparasitosis is associated with important morbidity. It causes disfigurement and mutilation of the feet. Feasible and effective treatment is not available. So far prevention is the only means to control tungiasis-associated morbidity.

Methodology

In two villages in Central Madagascar, we assessed the efficacy of the availability of closed shoes and the twice-daily application of a plant-based repellent active against sand fleas (Zanzarin) in comparison to a control group without intervention. The study population was randomized into three groups: shoe group, repellent group and control group and monitored for ten weeks. The intensity of infestation, the attack rate and the severity of tungiasis-associated morbidity were assessed every two weeks.

Findings

In the repellent group, the median attack rate became zero already after two weeks. The intensity of the infestation decreased constantly during the observation period and tungiasis-associated morbidity was lowered to an insignificant level. In the shoe group, only a marginal decrease in the intensity of infestation and in the attack rate was observed. At week 10, the intensity of infestation, the attack rate and the severity score for acute tungiasis remained significantly higher in the shoe group than in the repellent group. Per protocol analysis showed that the protective effect of shoes was closely related to the regularity with which shoes were worn.

Conclusions

Although shoes were requested by the villagers and wearing shoes was encouraged by the investigators at the beginning of the study, the availability of shoes only marginally influenced the attack rate of female sand fleas. The twice-daily application of a plant-based repellent active against sand fleas reduced the attack to zero and lowered tungiasis-associated morbidity to an insignificant level.

Tungiasis (sand flea disease) is a parasitic skin disease present in many resource-poor communities in South America, the Caribbean and sub-Saharan Africa. In this setting tungiasis is associated with important morbidity. 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. The prevention of the infestation is the only option to control morbidity. In this study we show that the twice daily application of a herbal repellent based on coconut-oil (Zanzarin), is highly effective in preventing sand flea disease in a heavily affected community in Madagascar. The attack rate became zero immediately after starting the application of the repellent. The degree of tungiasis associated morbidity approached zero within 10 weeks. In contrast, the availability of closed solid shoes had only a marginal protective effect; although shoes were requested by the villagers and wearing shoes was encouraged by the investigators at the beginning of the study. In a control group from the same village the attack rate, the intensity of infestation and of tungiasis-associated morbidity remained unchanged. Our study in rural Madagascar shows that effective und sustainable morbidity control is possible using a repellent derived from coconut oil.

Regression of severe tungiasis-associated morbidity after prevention of re-infestation: a case series from rural Madagascar

Tungiasis (sand flea disease) is a neglected tropical disease. Heavy infestation results in mutilation of the feet and difficulty in walking. We identified eight individuals with extremely severe tungiasis in rural Madagascar. To prevent reinfestation, four individuals received solid shoes and four received a daily application of an herbal repellent effective against Tunga penetrans. Over a period of 10 weeks the feet were examined and the severity of tungiasis-associated morbidity was measured. Within this period, the severity score for acute tungiasis decreased 41% in the shoe group and 89% in the repellent group. The four major inflammation-related symptoms disappeared in the four patients of the repellent group, but only in two patients of the shoe group. Those observations indicate that cases with extremely severe tungiasis, associated morbidity almost totally disappears within 10 weeks if the feet are protected by a repellent. Wearing shoes reduced acute morbidity only marginally.

Tungiasis: a neglected epidermal parasitic skin disease of marginalized populations--a call for global science and policy

Tungiasis (sand flea disease) is an ectoparasitic skin disease caused by the female sand flea/jigger flea (Tunga penetrans). As poverty is the major driving force of the disease, it can be called as a poverty-associated plague. It is one of the emerging neglected diseases in Latin America, Caribbean, sub-Saharan Africa, and India. The aim of the present scrutiny was to assess the public health impact of tungiasis, associated risk factors, and emerging opportunities to prevent and control tungiasis. Searches of PubMed, Google Scholar, and online search engines (Google, AOL, and Yahoo) using keywords "parasitic skin disease," "tungiasis," "sand flea," " tungiasis-associated risk factors," "tungiasis prevention and control," and their synonyms were used as a source of references. Searches were made without time limitations. Of 167 potential articles identified by these criteria, 51 appropriate were selected for review. Tungiasis is widespread in the resource-constrained settings of low-income economies. In the tropics, it is highly prevalent among the impoverished populations, but the associated risk factors are often poorly identified and remain uncontrolled. Though it is a self-limiting disease with considerable morbidity, the parasite may cause subsequent secondary morbidity through life-threatening complications and infections like cellulitis, tetanus, and death. However, the direct and indirect sociocultural, economic, and health impact of tungiasis is often undervalued and misunderstood. A systematic assessment on disease burden is still dearth and deficient. Over the decades, tungiasis has been largely neglected by the scientific community, policy makers, and healthcare stakeholders. In the endemic regions, even tungiasis is not listed for the disease control priorities in the regional, national, and international agenda. The majority of the epidermal parasitic skin diseases particularly tungiasis needs a sustainable global scientific research and control policy. This urges intensive efforts to develop a road map that delivers a clear vision towards zero new infection by designing low-cost prevention and control strategies. Besides, there is an urgency to develop culturally appropriate communication techniques and workable collaboration on a global scale by bringing all the stakeholders of endemic countries.

Insect repellents and associated personal protection for a reduction in human disease

Personal protection measures against biting arthropods include topical insect repellents, area repellents, insecticide-treated bednets and treated clothing. The literature on the effectiveness of personal protection products against arthropods is mainly limited to studies of prevention of bites, rather than prevention of disease. Tungiasis was successfully controlled by application of topical repellents and scrub typhus was reduced through the use of treated clothing. Successful reduction of leishmaniasis was achieved through the use of topical repellents, treated bednets and treated clothing in individual studies. Malaria has been reduced by the use of insecticide-treated bednets (ITN), certain campaigns involving topical repellents, and the combination of treated bednets and topical repellents. Although area repellents such as mosquito coils are used extensively, their ability to protect humans from vector-transmitted pathogens has not been proven. Taken together, the literature indicates that personal protection measures must be used correctly to be effective. A study that showed successful control of malaria by combining treated bednets and topical repellents suggests that combinations of personal protection measures are likely to be more effective than single methods. Implementation of successful programmes based on personal protection will require a level of cooperation commonly associated with other basic societal functions, such as education and food safety.

Tungiasis (sand flea disease): a parasitic disease with particular challenges for public health

Tungiasis (sand flea disease) is caused by the penetration of females of Tunga penetrans into the skin of the feet. Within 2 weeks of penetration the burrowed flea increases its volume by a factor of 2,000. This is paralleled by intense inflammation of the surrounding tissue. Acute and chronic inflammation leads to the development of painful and debilitating clinical pathology. This results in impaired physical fitness and mobility. The social implications of tungiasis-associated morbidity are multifold. Children with tungiasis are teased and ridiculed, adults feel ashamed and stigmatized. There is anecdotal evidence that tungiasis negatively affects educational achievements. Impaired mobility and physical fitness will have a negative impact on household economics. Sand flea disease is common in resource-poor communities in South America and in sub-Saharan Africa with prevalence in the general population of up to 60%. In East Africa, it has re-emerged in epidemic dimensions in recent years. Hitherto, no effective drug treatment has been at hand. Traditional treatment, i.e., the manipulation of burrowed sand fleas with blunt and inappropriate instruments may facilitate the transmission of blood-derived pathogens. Prevention is feasible through regular application of a repellent based on coconut oil. Owing to its strong association with poverty, sand flea disease would be an excellent starting point for a community-based fight against rural poverty.

Tungiasis: a poorly documented tropical dermatosis

Tungiasis is the parasitic skin disease caused by the sand flea Tunga penetrans, also called the jigger flea, found in most intertropical countries. The contamination occurs when walking barefoot in the sand: adult females actively burrow the foot epidermis leading to self-limited lesions responsible for itching or pain. The diagnosis is made on clinical observation and history of travelling to an endemic country. The simple treatment is surgical extraction of the flea.

Control of tungiasis through intermittent application of a plant-based repellent: an intervention study in a resource-poor community in Brazil

BACKGROUND

Tungiasis, an ectoparasitosis caused by the female sand flea Tunga penetrans, is an important health problem in many impoverished communities in the tropics. Sand flea disease is associated with a broad spectrum of clinical pathology and severe sequels are frequent. Treatment options are limited.

METHODOLOGY/PRINCIPAL FINDINGS

We assessed the effectiveness of the intermittent application of the plant-based repellent Zanzarin to reduce infestation intensity and tungiasis-associated morbidity in a resource-poor community in Brazil, characterized by a very high attack rate. The study population was randomized into three cohorts. Initially, during a period of four weeks, the repellent was applied twice daily to the feet of all cohort members. This reduced the number of embedded sandfleas to 0 in 98% of the participants. Thereafter members of cohort A applied the repellent every second week twice daily for one week, members of cohort B every fourth week for one week, and members of cohort C served as controls. Infestation intensity and tungiasis-associated morbidity were monitored during five months. The intermittent application of Zanzarin for one week every second week significantly reduced infestation intensity from a median 4 lesions (IQR 1-9) during the whole transmission season. In contrast, in cohort B (application of the repellent every fourth week) the infestation intensity remained twice as high (median 8 lesions, IQR 9-16; p = 0.0035), and in the control cohort C 3.5 times as high (median 14 lesions; IQR 7-26; p = 0.004 during the transmission season). Tungiasis-related acute pathology remained very low in cohort A (median severity score 2; IQR 1-4) as compared to cohort B (median severity score 5; IQR 3-7; p<0.001), and control cohort C (median severity score 6.5; IQR 4-8; p<0.001).

CONCLUSIONS/SIGNIFICANCE

Our study shows that in a setting with intense transmission, tungiasis-associated morbidity can be minimized through the intermittent application of a plant-based repellent.

Sand flea (Tunga spp.) infections in humans and domestic animals: state of the art

Tungiasis is a parasitic disease of humans and animals caused by fleas (Siphonaptera) belonging to the genus Tunga. Two species, Tunga penetrans (L.) and Tunga trimamillata, out of 10 described to date, are known to affect man or domestic animals; the other eight are exclusive to a few species of wild mammals. Tunga penetrans and T. trimamillata originated from Latin America, although the first species is also found in sub-Saharan Africa (between 20 degrees N and 25 degrees S). Hundreds of millions of people are at risk of infection in more than 70 nations, mostly in developing countries. The second species has been reported only in Ecuador and Peru. Males and non-fertilized females of Tunga are haematophagous ectoparasites; pregnant females penetrate the skin where, following dilatation of the abdomen, they increase enormously in size (neosomy) and cause inflammatory and ulcerative processes of varying severity. The importance of Tunga infection in humans concerns its frequent localization in the foot, which sometimes causes very serious difficulty in walking, thereby reducing the subject's ability to work and necessitating medical and surgical intervention. Tungiasis in domestic animals can be responsible for economic losses resulting from flea-induced lesions and secondary infections. Because tungiasis represents a serious problem for tropical public health and because of the recent description of a new species (Tunga trimamillata), it seems appropriate to review current knowledge of the morphology, molecular taxonomy, epidemiology, pathology, treatment and control of sand fleas of the genus Tunga.

Epidermal parasitic skin diseases: a neglected category of poverty-associated plagues

Epidermal parasitic skin diseases (EPSD) are a heterogeneous category of infectious diseases in which parasite-host interactions are confined to the upper layer of the skin. The six major EPSD are scabies, pediculosis (capitis, corporis and pubis), tungiasis and hookworm-related cutaneous larva migrans. We summarize the current knowledge on EPSD and show that these diseases are widespread, polyparasitism is common, and significant primary and secondary morbidity occurs. We show that poverty favours the presence of animal reservoirs, ensures ongoing transmission, facilitates atypical methods of spreading infectious agents and increases the chances of exposure. This results in an extraordinarily high prevalence and intensity of infestation of EPSD in resource-poor populations. Stigma, lack of access to health care and deficient behaviour in seeking health care are the reasons why EPSD frequently progress untreated and why in resource-poor populations severe morbidity is common. The ongoing uncontrolled urbanization in many developing countries makes it likely that EPSD will remain the overriding parasitic diseases for people living in extreme poverty. We advocate integrating control of EPSD into intervention measures directed against other neglected diseases such as filariasis and intestinal helminthiases.

Tungiasis in schoolchildren in Criciúma, Santa Catarina State, South Brazil

Tungiasis is a common parasitic skin disease in Brazil, caused by the flea Tunga penetrans. We conducted a cross-sectional study to evaluate the occurrence of infestation with T. penetrans in primary schoolchildren in Criciúma, Santa Catarina State (South Brazil). In total, 917 children (6-10 years) of 68 schools were included in the study (11% of target population). Physical examination was followed by residential visits of those infested, to assess housing conditions and to interview the children's guardians. Of the 917, 15 (1.6%) children were infested with the parasite. The prevalence was twice as high in females (10 children--2.2%) as compared to males (five children--1.1%), but due to the low number of infested individuals, the difference was statistically not significant (p = 0.18). The mean number of lesions found was 1.4 per child. One child presented bacterial superinfection. Of the 15 children infested, 10 (66.7%) studied in schools built on pyritiferous soil. The families of 12 children (79.9%) had been living in the area in which the study was conducted for less than eight years and were considered underprivileged families with the head of the household having a low education status. We conclude that in Criciúma tungiasis occurs in primary school children, but prevalence and parasite load are low.

[Tungiasis and myiasis]

Tungiasis (sand flea disease) and myiasis are ectoparasitoses, in which the infectious agent resides temporarily in the skin (myiasis) or dies and is eventually eliminated (tungiasis). Both diseases are zoonoses. Whereas in myiasis humans are only an accidental host, in tungiasis the prevalence in humans is similar to that of their domestic animals. In travellers returning from the tropics tungiasis and myiasis are not rare, however they are frequently misdiagnosed. The diagnosis of both infestations is made clinically, and laboratory investigations are not helpful. In tungiasis the clinical picture depends on the stage of the disease. A heavy local inflammation and bacterial superinfection are frequent. Therapy consists in the complete elimination of the parasite. The repellent Zanzarin effectively protects against sand fleas.

Controlling tungiasis in an impoverished community: an intervention study

Background

In Brazil, tungiasis is endemic in some resource-poor communities where various domestic and sylvatic animals act as reservoirs for this zoonosis. To determine the effect of control measures on the prevalence and intensity of infestation of human and animal tungiasis, a repeated cross-sectional survey with intervention was carried out.

Methodology/Principal Findings

In a traditional fishing community in Northeast Brazil, humans and reservoir animals were treated, and premise-spraying using an insecticide was done, while a second fishing community served as a control. Both communities were followed up 10 times during a 12-month period. At baseline, prevalence of tungiasis was 43% (95% confidence interval [CI]: 35%–51%) and 37% (95% CI: 31%–43%) in control and intervention villages, respectively. During the study, prevalence of tungiasis dropped to 10% (95% CI: 8%–13%; p<0.001) in the intervention village, while the prevalence remained at a high level in the control village. However, after one year, at the end of the study, in both communities the prevalence of the infestation had reached pre-intervention levels. Whereas the intensity of infestation was significantly reduced in the intervention community (p<0.001), and remained low at the end of the study (p<0.001), it did not change in the control village.

Conclusion/Significance

Our study shows that a reduction of prevalence and intensity of infestation is possible, but in impoverished communities a long-lasting reduction of disease occurrence can only be achieved by the regular treatment of infested humans, the elimination of animal reservoirs, and, likely, through environmental changes.

Trial Registration

Controlled-Trials.com ISRCTN27670575

Tungiasis is a disease caused by the sand flea Tunga penetrans, a parasite prevalent in many impoverished communities in developing countries. The female sand flea penetrates into the skin of animals and humans where it grows rapidly in size, feeds on the host's blood, produces eggs which are expelled into the environment, and eventually dies in situ. The lesions become frequently superinfected and the infestation is associated with considerable morbidity. Clearly, tungiasis is a neglected disease of neglected populations. We investigated the impact of a package of intervention measures targeted against on-host and off-host stages of T. penetrans in a fishing community in Northeast Brazil. These measures decreased disease occurrence only temporarily, but had a sustained effect on the intensity of the infestation. Since infestation intensity and morbidity are correlated, presumably the intervention also lowered tungiasis-associated morbidity. Control measures similar to the ones used in this study may help to effectively control tungiasis in impoverished communities.

[Tungiasis: a neglected disease causing severe morbidity in a shantytown in Fortaleza, State of Ceará]

The parasitic skin disease tungiasis, caused by the jigger flea Tunga penetrans, is endemic in low-income communities in Brazil. In this study, inhabitants of a shantytown in Fortaleza, northeastern Brazil, who had an elevated parasite load, were identified. The number of lesions, localization, staging and associated diseases were recorded. The 142 individuals identified were living in extremely precarious housing conditions. A total of 3,445 lesions located on the feet were counted (median = 17 lesions; maximum = 98 lesions). Almost without exception, the individuals had nail deformation and edema, and more than 70% presented with pain and fissures. There was nail loss in 46%; deformation of the digits in 25%; abscesses in 42%; and complaints of walking difficulty in 59%. Our data show that tungiasis in this low-income urban community typical of northeastern Brazil was associated with severe morbidity. Tungiasis needs to be recognized as a public health problem in this study area and other similar endemic areas.

Morbidity assessment in sand flea disease (tungiasis)

Tungiasis, caused by the sand flea Tunga penetrans, is a health problem in many impoverished communities in Latin America, the Caribbean, and sub-Saharan Africa. Sand flea disease is associated with a broad spectrum of clinical and histological pathology. The factors determining the disease burden in endemic communities are not well understood, and severity of clinical pathology has never been assessed quantitatively. Thus, two severity scores were developed: one for acute disease and one for chronic sequels. These scores were evaluated in a cohort of 70 severely infested patients living in a shantytown in Fortaleza, a capital city in Northeast Brazil. Patients were examined during a period of 25 days and followed-up after a twice daily application of a plant-based repellent to prevent reinfestation. The severity score for acute disease symptoms significantly correlated with the infestation rate and the number of embedded fleas. It turned zero when reinfestation was prevented. The score for chronic disease also significantly correlated with the infestation rate. Tungiasis is associated with considerable acute and chronic morbidity. The degree of acute morbidity is directly related to the number of embedded sand fleas. When transmission is interrupted, the chronic morbidity reflects the infestation rates individuals have experienced in the past.