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

Identification of tungiasis infection hotspots with a low-cost, high-throughput method for extracting Tunga penetrans (Siphonaptera) off-host stages from soil samples-An observational study

BACKGROUND

The sand flea, Tunga penetrans, is the cause of a severely neglected parasitic skin disease (tungiasis) in the tropics and has received little attention from entomologists to understand its transmission ecology. Like all fleas, T. penetrans has environmental off-host stages presenting a constant source of reinfection. We adapted the Berlese-Tullgren funnel method using heat from light bulbs to extract off-host stages from soil samples to identify the major development sites within rural households in Kenya and Uganda.

METHODS AND FINDINGS

Simple, low-cost units of multiple funnels were designed to allow the extraction of >60 soil samples in parallel. We calibrated the method by investigating the impact of different bulb wattage and extraction time on resulting abundance and quality of off-host stages. A cross-sectional field survey was conducted in 49 tungiasis affected households. A total of 238 soil samples from indoor and outdoor living spaces were collected and extracted. Associations between environmental factors, household member infection status and the presence and abundance of off-host stages in the soil samples were explored using generalized models. The impact of heat (bulb wattage) and time (hours) on the efficiency of extraction was demonstrated and, through a stepwise approach, standard operating conditions defined that consistently resulted in the recovery of 75% (95% CI 63-85%) of all present off-host stages from any given soil sample. To extract off-host stages alive, potentially for consecutive laboratory bioassays, a low wattage (15-25 W) and short extraction time (4 h) will be required. The odds of finding off-host stages in indoor samples were 3.7-fold higher than in outdoor samples (95% CI 1.8-7.7). For every one larva outdoors, four (95% CI 1.3-12.7) larvae were found indoors. We collected 67% of all off-host specimen from indoor sleeping locations and the presence of off-host stages in these locations was strongly associated with an infected person sleeping in the room (OR 10.5 95% CI 3.6-28.4).

CONCLUSION

The indoor sleeping areas are the transmission hotspots for tungiasis in rural homes in Kenya and Uganda and can be targeted for disease control and prevention measures. The soil extraction methods can be used as a simple tool for monitoring direct impact of such interventions.

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.

Measuring educational neglect using the Q method: A model based on the burden of disseminated tungiasis

Background

A paramount factor in the control of neglected tropical diseases from both medical and social aspects is education. New strategies must be constantly pursued to test and provide educational information related to diseases affecting vulnerable populations. We applied the Q method as a model to measure educational neglect based on the burden of disseminated tungiasis.

Methods

Using a saturation method for sample size calculation, we recruited students and healthcare professionals to evaluate and classify 27 statements related to the prevention, control and treatment of tungiasis. After quantitative analysis, the Q method was applied based on the paired use of the centroid method and Varimax rotation, and 4 factors were extracted representing the main sets of viewpoints among the participants.

Results

We included 119 healthcare professionals with different academic degrees. Statements classified by specialists with a + agreement were also classified as a + agreement by most of the participants. However, we detected 5 important disagreements related to the topical treatment of tungiasis and control of the disease in the environment and animals. The Q method showed that almost no consensus was detected for four statements. The classification of each statement was not related to the participants' academic degree.

Conclusions

There is significant educational neglect related to tungiasis prevention and treatment in healthcare sciences in Brazil. We conclude that the Q method may be an interesting strategy alone or associated with quantitative strategies for detecting educational limitations related to neglected diseases. In countries where neglected diseases are endemic, a detailed study evaluating the quality of education related to these diseases must be prioritized.

Antiparasitic Activity of Tea Tree Oil (TTO) and Its Components against Medically Important Ectoparasites: A Systematic Review

Ectoparasites are pathogens that can infect the skin and cause immense pain, discomfort, and disease. They are typically managed with insecticides. However, the fast-emerging antimicrobial resistance and the slow rate of development of new bio-actives combined with environmental and health concerns over the continued use of neurotoxic insecticides warrant newer and alternative methods of control. Tea tree oil (TTO), as an alternative agent, has shown remarkable promise against ectoparasites in recent studies. To our knowledge, this is the first systematic review to assess preclinical and clinical studies exploring the antiparasitic activity of TTO and its components against clinically significant ectoparasites, such as Demodex mites, scabies mites, house dust mites, lice, fleas, chiggers, and bed bugs. We systematically searched databases, including PubMed, MEDLINE (EBSCOhost), Embase (Scopus), CENTRAL, Cochrane Library, CINAHL, ScienceDirect, Web of Science, SciELO, and LILACS in any language from inception to 4 April 2022. Studies exploring the therapeutic activity of TTO and its components against the ectoparasites were eligible. We used the ToxRTool (Toxicological data reliability assessment) tool, the Joanna Briggs Institute (JBI) critical appraisal tools, and the Jadad scale to assess the methodological qualities of preclinical (in vitro and in vivo) studies, non-randomised controlled trials (including cohort, case series, and case studies), and randomised controlled trials, respectively. Of 497 identified records, 71 studies were included in this systematic review, and most (66%) had high methodological quality. The findings of this review revealed the promising efficacy of TTO and its components against ectoparasites of medical importance. Most importantly, the compelling in vitro activity of TTO against ectoparasites noted in this review seems to have translated well into the clinical environment. The promising outcomes observed in clinical studies provide enough evidence to justify the use of TTO in the pharmacotherapy of ectoparasitic infections.

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.

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.