Neurocognitive and mental health outcomes in children with tungiasis: a cross-sectional study in rural Kenya and Uganda.

BACKGROUND: Tungiasis, a neglected tropical parasitosis, disproportionately affects children. Few empirical studies have reported neurocognitive and mental health outcomes of children with ectoparasitic skin diseases like tungiasis. Pathophysiology of tungiasis suggests it could detrimentally affect cognition and behaviour. This study pioneered the investigation of neurocognitive and mental health outcomes in children with tungiasis. METHODS: This was a multi-site cross-sectional study including 454 quasi-randomly sampled school-children aged 8-14 from 48 randomly selected schools in two counties in Kenya and a district in Uganda. The participants were stratified into infected and uninfected based on the presence of tungiasis. The infected were further classified into mild and severe infection groups based on the intensity of the infection. Adapted, validated, and standardized measures of cognition and mental health such as Raven Matrices and Child Behaviour Checklist were used to collect data. Statistical tests including a multilevel, generalized mixed-effects linear models with family link set to identity were used to compare the scores of uninfected and infected children and to identify other potential risk factors for neurocognitive and behavioural outcomes. RESULTS: When adjusted for covariates, mild infection was associated with lower scores in literacy [adjusted ß(aß) = - 8.9; 95% confidence interval (CI) - 17.2, - 0.6], language (aß = - 1.7; 95% CI - 3.2, - 0.3), cognitive flexibility (aß = - 6.1; 95% CI - 10.4, - 1.7) and working memory (aß = - 0.3; 95% CI - 0.6, - 0.1). Severe infection was associated with lower scores in literacy (aß = - 11.0; 95% CI - 19.3, - 2.8), response inhibition, (aß = - 2.2; 95% CI - 4.2, - 0.2), fine motor control (aß = - 0.7; 95% CI - 1.1, - 0.4) and numeracy (aß = - 3; 95% CI - 5.5, - 0.4). CONCLUSIONS: This study provides first evidence that tungiasis is associated with poor neurocognitive functioning in children. Since tungiasis is a chronic disease with frequent reinfections, such negative effects may potentially impair their development and life achievements.

The efficacy of topical, oral and surgical interventions for the treatment of tungiasis: A systematic review of the literature.

BACKGROUND: Tungiasis is a neglected disease caused by Tunga penetrans that can be complicated by secondary infections and local tissue destruction. Adequate treatment is important, especially in vulnerable populations; potential treatment options proposed range from surgical extraction to the use of oral and topical medications. We aimed to perform a systematic review to assess the efficacy of topical, oral and surgical interventions for the treatment of tungiasis. METHODOLOGY/PRINCIPAL FINDINGS: The present review is registered in PROSPERO (CRD42021234741). On September 1, 2020, we searched PubMed, EMBASE, Scopus, Web of Science, Science Direct, Scielo and LILACS BVS. We included clinical trials and longitudinal observational studies that evaluated any topical, systemic or mechanical treatment for tungiasis. We used the Revised Cochrane Risk of Bias (RoB) Tool for Randomized Trials for clinical trial analysis. Qualitative and quantitative descriptive syntheses were performed. Our search strategy resulted in 3376 references. Subsequently, 2568 titles/abstracts and 114 full texts were screened. We finally included 19 articles; 9 were classified as clinical trials. Two and 3 articles presented low and some RoB, respectively, according to the tool. Only two articles tested the efficacy of oral medications (niridazole, ivermectin), with discouraging results. Six clinical trials evaluated topical products for the treatment of tungiasis; 2 evaluated dimeticone-based compounds and reported positive results in lesion reduction and cure. None reported significant adverse reactions. Surgical extraction was evaluated only in observational studies. CONCLUSIONS/SIGNIFICANCE: We conclude that, although surgical extraction is the most commonly used treatment, there is sufficient evidence supporting the use of occlusive agents, especially manufactured dimeticone-based products.

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.

Clinical and pathological aspects of first report of Tunga penetrans infestation on southern brown howler monkey (Alouatta guariba clamitans) in Rio Grande do Sul, Brazil.

BACKGROUND: Tungiasis is a neglected neotropical disease caused by penetration of Tunga spp. into the skin of the host. METHODS: Two primates were rescued from nearby different indigenous villages, and the clinical, pathological, and parasitological features of tungiasis were described. Flea identification occurred through their morphometry and was confirmed with the use of a dichotomous key. RESULTS: Monkey 1 was parasitized by 23 sand fleas and, after treatment, was assigned to the animal rehabilitation center. Monkey 2 was in poor body condition and died shortly after clinical examination. At necropsy, this primate was parasitized by 26 specimens of sand fleas. CONCLUSIONS: Both animals altered their tree behavior by staying on the ground for long periods. This parasitic relationship implies the possibility of enlargement of the sand flea dispersion. Thus, this is the first record of Tunga penetrans occurrence in wild Alouatta guariba clamitans.

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.

Seasonal variation and persistence of tungiasis infestation in dogs in an endemic community, Bahia State (Brazil): longitudinal study.

Tungiasis is a zoonosis neglected by authorities, health professionals, and affected populations. Domestic, synanthropic, and sylvatic animals serve as reservoirs for human infestation, and dogs are usually considered a main reservoir in endemic communities. To describe the seasonal variation and the persistence of tungiasis in dogs, we performed quarterly surveys during a period of 2 years in a tourist village in the municipality of Ilhéus, Bahia State, known to be endemic for tungiasis. Prevalence in dogs ranged from 62.1% (43/66) in August 2013 to 82.2% (37/45) in November 2014, with no significant difference (p = 0.06). The prevalence of infestation remained high, regardless of rainfall patterns. Of the 31 dogs inspected at all surveys, period prevalence was 94% (29/31; 95% CI 79.3-98.2%) and persistence of infestation indicator [PII] was high (median PII = 6 surveys, q1 = 5, q3 = 7). Dogs < 1 year of age had a higher mean prevalence of 84.5%, as compared with 69.3% in the older dogs. No significant difference was found between the risk of infestation and age or sex (p = 0.61). Our data indicate that canine tungiasis persisted in the area during all periods of the year. The seasonal variation described in human studies from other endemic areas was not observed, most probably due to different rainfall patterns throughout the year. The study has important implications for the planning of integrated control measures in both humans and animal reservoirs, considering a One Health approach.

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.

Tungiasis-associated morbidity in pigs and dogs in endemic villages of Uganda.

BACKGROUND: Tunga penetrans (Insecta, Siphonaptera, Tungidae) causes severe morbidity among heavily infected humans and animals in Latin America and sub-Saharan Africa. The clinical pathology of tungiasis in animals has never been studied systematically. METHODS: This was a cross-sectional study conducted between January to March 2015, aimed at describing tungiasis-associated clinical pathology in 121 and 20 T. penetrans-infected pigs and dogs, living in nine and five endemic rural villages respectively located in Bugiri District, Busoga, Uganda. RESULTS: The parasite load of infected animals ranged from one to 246 (median 8) and one to eight (median 2) in pigs and dogs, respectively. In pigs 99.3% and in dogs 100% of the lesions were located on feet. In pigs, hind legs were significantly more affected than front legs (90.9% vs. 57.9%; p = 0.002) and also had more lesions than the front legs (median 5 vs. 1; p = 0.0001). However, in dogs localization of lesions between front and hind legs never differed significantly (front, 50% vs. hind, 65%; p = 0.51) and so were the number of lesions (median front = 0.5 vs. median hind = 2; p = 0.7). Acute and chronic clinical pathology coexisted. The most common disease manifestations in pigs were hoof wall erosions (68.6%), tissue necrosis of hoof wall and skin (66.1), pain at infection sites (47.9%), hoof deformity (45.5%), fissures (44.6%) and edema (44.6%). In dogs, tungiasis mainly presented with pain at attachment site (80%), ulcers (55%), necrosis (30%) as well as hyperemia and edema (both 15%). One pig had lost dew claws while two had loose detaching claws. Despite a lower number of sand fleas, a higher proportion of infected dogs (20%) than pigs (5.8%) exhibited functional limb use difficulties (p = 0.05). CONCLUSIONS: The pattern of clinical manifestations in pigs and dogs were very similar to those reported from affected humans and rats. The important morbidity associated with animal tungiasis makes the disease a serious veterinary health problem in sub-Saharan Africa warranting treatment and control for optimal animal production.

A new species of Tunga perforating the osteoderms of its armadillo host in Argentina and redescription of the male of Tunga terasma.

A new species of Tunga (Siphonaptera: Tungidae) collected from armadillos in Argentina is described. The new species is characterized by large and pigmented eyes, the presence of two bristles on antennal segment II, two bristles at the base of the maxilla, and a discoid neosome compressed anteroposteriorly. The gravid female is located in the carapace of the host, perforating the osteoderms. The new species resembles Tunga penetrans and Tunga terasma in general appearance. However, it differs by the greater anteroposterior compression of the neosome, a more angular head, and a manubrium with a pointed proximal end and convex ventral margin (the proximal end of the manubrium is rounded or slightly pointed in T. terasma, and the ventral margin is straight in both T. penetrans and T. terasma). In addition, specimens of T. penetrans have more bristles in antennal segments II and III, and lack bristles in the posterior tibia. This is the first report of a species of Tunga perforating the osteoderms of its host and thereby showing a high degree of specialization. Tunga terasma is recorded for the first time in Argentina; the male is described again and the characteristics of the species amended. This information may be useful in epidemiological studies of diseases caused by species of Tunga.

Neosomes of tungid fleas on wild and domestic animals.

Tunga is the most specialized genus among the Siphonaptera because adult females penetrate into the skin of their hosts and, after mating and fertilization, undergo hypertrophy, forming an enlarged structure known as the neosome. In humans and other warm-blooded animals, neosomes cause tungiasis, which arises due to the action of opportunistic agents. Although its effects on humans and domestic animals are well described in the literature, little is known about the impact of tungiasis on wild animals. This review focuses on the morphology, taxonomy, geographical distribution, hosts, prevalence, sites of attachment, and impact of tungid neosomes on wild and domestic animals. Because neosomes are the most characteristic form of the genus Tunga and also the form most frequently found in hosts, they are here differentiated and illustrated to aid in the identification of the 13 currently known species. Perspectives for future studies regarding the possibility of discovering other sand flea species, adaptation to new hosts, and the transfer of tungids between hosts in natural and modified habitats are also presented.

The fate of the embedded virgin sand flea Tunga penetrans: hypothesis, self-experimentation and photographic sequence.

We describe the morphological development of a single penetrated female sand flea (Tunga penetrans) in a medical expatriate working in Madagascar. The embedded parasite developed abnormally in two aspects. First, it lived twice as long as usually. Second, it did not expel a single egg during a period of two months. We explain these abnormalities by the fact that the female sand flea remained virgin after the penetration into the skin and, therefore, mature eggs did not develop. Our observations are seminal findings in a long dispute between entomologists and suggest that normally the fertilization of a female sand flea takes place on-host when it is already embedded in the epidermis. We conclude that a single sand flea lesion in a traveller may develop in a different way as compared to parasites penetrating into the skin of inhabitants living in endemic areas.

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.

Establishment of Tunga trimamillata (Siphonaptera: Tungidae) in Brazil.

Tunga trimamillata is a species of sand flea occurring in Ecuador and Peru parasitizing cattle, goat, sheep, swine, and man. This is the first report of this species in Brazil, having been found on the hooves of cows in Barretos, São Paulo State, and Felixlândia, Minas Gerais State, and previously misidentified as Tunga penetrans. A previous report concerning Hydrochoerus hydrochaeris from Rio Novo, Minas Gerais State, may also be attributed to that species of sand flea, a possible the primary host. Given the large geographical distribution of T. trimamillata, the vast cattle population in Brazil, and the high number of individuals subject to the risk of tungiasis, the number of cases attributed to this sand flea will most likely increase over time.

[The genus Tunga Jarocki, 1838 (Siphonaptera: Tungidae). I: taxonomy, phylogeny, ecology and pathogenicity]. / Le genre Tunga Jarocki, 1838 (Siphonaptera : Tungidae). I - Taxonomie, phylogénie, écologie, rôle pathogène.

This is the first review of the taxonomy and geographical range of the 12 known species of the genus Tunga. Their biology and pathogenic roles are considered, with particular emphasis on their phylogeny, chorology, phenology, sex-ratio, and dermecos.

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.