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

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.

National prevalence and risk factors for tungiasis in Kenya

BACKGROUND

Tungiasis is a highly neglected tropical skin disease caused by the sand flea, Tunga penetrans, the female of which burrows into the skin, causing pain and itching. The disease occurs throughout South America and sub-Saharan Africa but there are few systematic data on national disease burdens. The tungiasis research community is keen to develop survey methods to fill this gap. Here we used a school-based, thorough examination method to determine the prevalence and risk factors for tungiasis in Kenya.

METHODS

We conducted the first nationally representative survey of tungiasis, including nine counties covering the major ecological zones of Kenya. A stratified multistage random sampling was used to select 22 primary schools from each of the nine counties and to select up to 114 pupils aged 8 to 14 years in each school. Pupils were examined thoroughly for tungiasis. Two surveys were conducted, the first between May and July 2021 and the second between October 2021 and April 2023 when pupils were also interviewed for risk factors. Mixed effect logistic regression models were used to test associations of independent variables with tungiasis using the school as a random effect.

RESULTS

The overall prevalence of tungiasis in the first survey was 1.35% [95% confidence interval (CI): 1.15-1.59%], and 0.89% in the second survey. The prevalence ranged from 0.08% (95% CI: 0.01-0.59%) in Taita Taveta county to 3.24% (95% CI: 2.35-4.44%) in Kajiado county. Tungiasis infection was associated with county of residence, male sex [adjusted odds ratio (aOR) = 2.01, 95% CI: 1.52-2.67], and lower age (aOR = 0.81, 95% CI: 0.75-0.88). For the first time we demonstrate an association with attending public schools rather than private schools (aOR = 5.62, 95% CI: 1.20-26.22) and lower socioeconomic status (aOR = 0.10, 95% CI: 0.03-0.33). Using a rapid screening method of the top of feet only, would have missed 62.9% of all cases, 78.9% of mild cases and 20.0% of severe cases.

CONCLUSIONS

Tungiasis is widely but heterogeneously distributed across Kenya. School-based surveys offer an efficient strategy for mapping tungiasis distribution.

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.

Clinical and epidemiological survey of tungiasis in Madagascar

BACKGROUND

Tungiasis is a dermal parasitic infection, classified as a neglected tropical disease. Madagascar is one of endemic countries which have been committed for decades to control the tungiasis as a public health issue. Despite this medical importance, little is known about the prevalence and epidemiology of the disease in this country.

METHODS

A descriptive cross-sectional survey was performed in two endemic foci of Antananarivo and Toamasina.

RESULTS

In total, 2971 suspected individuals were surveyed. Of them, 643 individuals were excluded due to absence or refusing clinical examinations. Therefore, 2328 individuals with aforementioned criteria were clinically examined, 320 cases (13.7%) were found infected by Tunga penetrans. Of these 320 infected cases, 241 individuals came from rural regions against 79 from urban areas. The sex ratio of infected cases was 1.15 with an age average of 34.7 years old. Most of them were illiterate (185/320, 57.8%) with no habit of feet washing (210/320, 65.6%). The majority (198/320, 61.9%) inhabited in the houses constructed by falafa providing a suitable breeding location for Tunga ectoparasites. Based on clinical examination, most of the patients (298/320, 93.1%) had the lesions on their toes followed by those possessed the lesions on the plantar (140/320, 43.7%). The lesion stages of IV and V were observed in 49.1% (157/320) of visited patients which were more common in rural regions (86%) than in urban areas (14%). For treatment, removing the fleas using needle (122/320, 38.1%), followed by the application of petroleum (100/320, 31.2%) were among the most traditional remedies used by our patients.

CONCLUSION

This investigation highlights a high burden of tungiasis in studied endemic foci in particular in rural regions. These results can be helpful in control management strategies against this parasitosis in Madagascar.

Environmental and Household-Based Spatial Risks for Tungiasis in an Endemic Area of Coastal Kenya

Tungiasis is a cutaneous parasitosis caused by an embedded female sand flea. The distribution of cases can be spatially heterogeneous even in areas with similar risk profiles. This study assesses household and remotely sensed environmental factors that contribute to the geographic distribution of tungiasis cases in a rural area along the Southern Kenyan Coast. Data on household tungiasis case status, demographic and socioeconomic information, and geographic locations were recorded during regular survey activities of the Health and Demographic Surveillance System, mainly during 2011. Data were joined with other spatial data sources using latitude/longitude coordinates. Generalized additive models were used to predict and visualize spatial risks for tungiasis. The household-level prevalence of tungiasis was 3.4% (272/7925). There was a 1.1% (461/41,135) prevalence of infection among all participants. A significant spatial variability was observed in the unadjusted model (p-value < 0.001). The number of children per household, earthen floor, organic roof, elevation, aluminum content in the soil, and distance to the nearest animal reserve attenuated the odds ratios and partially explained the spatial variation of tungiasis. Spatial heterogeneity in tungiasis risk remained even after a factor adjustment. This suggests that there are possible unmeasured factors associated with the complex ecology of sand fleas that may contribute to the disease's uneven distribution.

Distribution of tungiasis in latin America: Identification of areas for potential disease transmission using an ecological niche model

Background

Tungiasis is a neglected tropical disease (NTD) found in Sub-Saharan Africa and Latin America. Despite the high frequency in marginalized populations, little information is available on the geography and estimates of the population at risk in endemic regions. Here we used a geostatistical model to map the potential geographic distribution of areas suitable for tungiasis transmission in Latin America and estimated the at-risk population.

Methods

We developed an ecological niche model (ENM) using tungiasis occurrence records and remotely sensed environmental and socioeconomic data. The potential geographic distribution was then compared to the current population distribution of the region to derive the total population living in urban and rural areas.

Findings

We identified a total of 138 records of occurrences of tungiasis in Latin America, ranging from Mexico to Argentina; 27 reports were not included in the modeling, due to missing detailed geographic information. The occurrences with detailed geographic information (n = 112) included 17 countries in Latin America and the Caribbean. The locations were in environments that primarily consisted of forests (29%), croplands (16•5%), and shrublands (10•9%). We predicted environmentally suitable areas for tungiasis transmission in 45 countries. The estimated human population living in these areas is 450,546,547 with urban centers accounting for 347,007,103 and rural areas 103,539,444. Countries with significant ecological suitability and documented occurrences include Brazil, Colombia, Mexico, Argentina, Bolivia, Ecuador, French Guyana, Guatemala, Haiti, Paraguay, Peru, Trinidad and Tobago, and Venezuela.

Interpretation

This is the first study mapping the potential distribution of tungiasis in Latin America, evidencing the need for population-based studies and elaboration of integrated control measures.

Funding

This project was supported in part by an appointment to the Research Participation Program at the Centers for Disease Control and Prevention administered by the Oak Ridge Institute for Science and Education through an interagency agreement between the U.S. Department of Energy and the Centers for Disease Control and Prevention.

Prevalence of multidrug-resistant bacteria in Ethiopia: a systematic review and meta-analysis

OBJECTIVES

Multidrug-resistant (MDR) bacteria are a significant public-health threat worldwide, especially in low- and middle-income countries. Comprehensive data are important to understand the magnitude of multidrug resistance (MDR), however these are not available in Ethiopia.

METHODS

Five electronic databases and grey literature of Addis Ababa University Repository were searched for data regarding the prevalence of MDR bacteria in Ethiopia. OpenMetaAnalyst R1.3 was used for analysis using a random-effects model to determine the effect size. Heterogeneity among articles was checked using the inconsistency index (I²). Funnel plot was used to check for publication bias. The quality of each article was checked using the Newcastle-Ottawa checklist adapted for cross-sectional studies.

RESULTS

Through database searching, 2094 articles were identified, of which 37 fulfilled the study inclusion criteria. This review comprises 6856 bacteria, of which 4949 isolates were MDR. The overall pooled prevalence of MDR was 70.5% (95% CI 64.9-76.1%), with considerable heterogeneity (I² = 97.48%, P < 0.001). Funnel plot revealed no publication bias. Sidama (81.7%) had the highest MDR and Tigray (51.1%) the lowest. The greatest source of MDR was from multiple sites of infection (MSI) (76.8%); the least was from bloodstream infections (62.9%). MDR was higher in studies conducted on hospital-acquired infections (72.1%) compared with both hospital- and community-acquired infections (69.8%).

CONCLUSION

Our study indicates a high prevalence of MDR in Ethiopia. Sidama region, MSI and hospital-acquired infections showed the highest MDR in subgroup analysis. Regional hospitals should implement infection prevention and proper use of antibiotics in the community.

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.

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.