Scabies prevalence and risk factors in internally displaced persons in Hargeisa, Somaliland: a cross-sectional survey

Introduction

Globally, scabies remains a major public health concern, disproportionately affecting marginalized communities and resource-limited settings due to overcrowding, inadequate sanitation, and limited healthcare access (1). Scabies, caused by the mite Sarcoptes scabiei var. hominis, spreads primarily through prolonged skin-to-skin contact and affects individuals across all ages, ethnicities, and socioeconomic strata (2). In response to its growing burden, the World Health Organization (WHO) designated scabies as a neglected tropical disease (NTD) in 2017 and included it in the 2021–2030 NTD Roadmap to advance control and elimination efforts (3, 4).

An estimated 300 million cases occur annually worldwide (5, 6), though underreporting, diagnostic challenges, and poor surveillance integration suggest the true burden is likely higher. Similar high burdens have also been reported in South Asia. including a recent study from Pakistan showing significant transmission in underserved urban populations (7). Transmission is influenced by behavioral and environmental factors, including limited health education, crowded sleeping conditions, sharing of bedding or clothing, and barriers to healthcare (7–10). Seasonal and climatic variations, along with population mobility between endemic and non-endemic areas, further shape infestation dynamics (11). Vulnerable groups—such as children, older adults, and immunocompromised individuals—often experience more severe disease manifestations, including crusted scabies.

Prevalence is notably elevated in under-resourced regions, frequently exceeding 20% in community-based surveys (12). In Ethiopia, for example, documented rates range from 9.3% to 11% (13–17). Scabies has been described as an indicator of socioeconomic inequity, with prevalence reaching 18–70% among marginalized populations in India, the South Pacific, and Aboriginal communities in Australia (10). These groups often face compounded barriers to care, including high treatment costs and limited access, leading to untreated household contacts and recurrent infestations.

Beyond epidemiological estimates, qualitative and mixed-methods studies highlight the importance of understanding local perceptions, health-seeking behaviors, and knowledge gaps. Research in Guinea-Bissau, for instance, revealed widespread misconceptions, care-seeking delays, and inappropriate management practices, underscoring the need for culturally adapted health education (18). Other investigations stress the importance of strengthening healthcare worker training, early detection, and affordable treatment access, particularly in settings where mass drug administration (MDA) may be considered (19).

Despite documented high prevalence in neighboring countries (13, 14, 20–22) and frequent cross-border movement, no epidemiological data exist on scabies in Somaliland. This gap is especially concerning given the country’s large internally displaced persons (IDP) settlements, where conditions conducive to transmission severe overcrowding, poor sanitation, and constrained healthcare access are widespread. The absence of scabies-specific surveillance, targeted interventions, or baseline estimates further perpetuates the invisibility of the disease in national health planning. Previous evidence suggests a possible link between scabies and systemic conditions such as anemia, possibly mediated through chronic inflammation, secondary bacterial infection, or underlying socioeconomic vulnerabilities (10). However, this relationship remains poorly understood, particularly in internally displaced populations. This study therefore aims to (1) determine the prevalence of scabies and (2) identify key biological and social determinants of transmission among IDP communities in Hargeisa, Somaliland. Findings will provide the first evidence base for scabies control and inform context-appropriate public health strategies for this neglected population.

Methods

Study design

We conducted an observational cross-sectional study at the end of the year to estimate the prevalence of scabies and examine associated sociodemographic and biological determinants among IDPs living in Hargeisa, Somaliland (23). This design enabled measurement of disease burden and exploration of correlates of infestation at a single point in time.

Study setting

The study was implemented in three IDP settlements in Hargeisa (Figure 1): Ayax 1, Mohammed Mooge B, and Dami B. These sites were selected to represent diverse demographic and geographic profiles within Maroodi Jeex Region. Ayax 1, located in the 31 May District (latitude 9.53343, longitude 44.04196), comprised approximately 600 households (population 3,600). Mohammed Mooge B in Mohammed Mooge District (latitude 9.53775, longitude 44.10366) consisted of 300 households (population 1,800), while Dami B in Gacan Libaax District (latitude 9.57294, longitude 44.06957) included 200 households (population 1,200). Collectively, the settlements formed a sampling frame of approximately 6,600 IDP residents.

Study population

The study population included IDP residents of all ages, including children under 5 years and older adults. Eligible participants were permanent residents of the selected settlements and provided informed consent. Individuals declining participation, temporary visitors, non-IDP residents, and recent immigrants were excluded.

Definition of confirmed, probable and suspected cases

Scabies cases were classified according to the International Alliance for the Control of Scabies (IACS) 2020 consensus criteria. Confirmed cases required direct visualization of mites, eggs, or feces via microscopy, high-power imaging, or dermoscopy. Clinical (probable) cases were defined by either (a) presence of scabies burrows, (b) typical genital lesions, or (c) typical lesions in a typical distribution plus two history features (e.g., pruritus, household contact). Suspected cases presented with either typical lesions plus one history feature, or atypical lesions/distribution with two history features (25, 26).

Sample size and sampling procedure

Based on an estimated target population of 6600 IDPs, across the three selected settlements, a sample size of n=362 was calculated using the Krejcie and Morgan (1970) formula. The calculation assumed a 95% confidence level and 5% margin of error, which is appropriate for estimating proportions in finite populations (27). Proportional allocation was applied across the three settlements (Ayax 1: 196; Mohammed Mooge B: 100; Dami B: 66). A stratified random sampling approach ensured representation from each settlement relative to population size.

Data collection

Data were collected through face-to-face interviews using a semi-structured questionnaire administered to adult participants or caregivers of young children. The instrument captured sociodemographic information, living conditions, medical history, and biological factors potentially associated with scabies. The questionnaire was pilot tested to ensure clarity and cultural relevance. To minimize interviewer and misclassification bias, all data collectors received standardized training.

Participants presenting with symptoms consistent with scabies were referred for clinical evaluation, and skin scrapings or exudates from suppurative lesions were collected following established procedures. All samples were labeled with unique identifiers to maintain confidentiality and ensure proper linkage to demographic data.

Laboratory procedures

Specimens were placed on clean microscope slides and treated with 10% potassium hydroxide (KOH). Slides were examined microscopically for mites, eggs, or fecal pellets of Sarcoptes scabiei var. hominis. For quality assurance, all positive samples and a random 10% of negative samples were re-examined by a second laboratory scientist.

Data analysis

Data were entered into Microsoft Excel, cleaned for completeness and consistency, and exported to SPSS version 25 (IBM Corp., Armonk, NY, USA) for statistical analysis. Descriptive statistics were used to summarize participant characteristics, presented as frequencies and percentages for categorical variables, and medians with interquartile ranges (IQRs) for continuous variables. Prevalence estimates for confirmed, probable, suspected, and total scabies cases were calculated with 95% confidence intervals (CIs). For comparisons across the four case categories (confirmed, probable, suspected, non-case), statistical comparisons focused primarily on trends across the groups given the small number of confirmed cases. Prior to model fitting, multicollinearity among independent variables was assessed using variance inflation factors with no evidence of multicollinearity (VIF < 5 for all variables). A multivariable logistic regression model was then built to identify independent risk factors for clinically significant scabies (confirmed and probable cases combined vs. non-cases). Variables significant at p<0.10 in univariate analysis, along with key demographic confounders (age, gender, income, education), were entered into a backward stepwise selection procedure. Model fit was assessed using the Hosmer–Lemeshow test and Nagelkerke’s R². Adjusted odds ratios (aORs) with 95% CIs are reported. Statistical significance was set at p<0.05.

Ethical considerations

The study adhered to the ethical principles outlined in the Declaration of Helsinki. Written informed consent was obtained from all participants, with parental consent provided for minors. Ethical approval was granted by the University of Hargeisa Ethical Review Committee (DRCS/52/05/2022), and permission to conduct the study was obtained from the Somaliland Ministry of Health Development (MOHD/DG: 2/585/2022). Participants found positive for scabies were referred for free treatment through the local health authorities.

Results

Characteristics of study participants

A total of 362 individuals from three internally displaced person (IDP) sites were enrolled in the study. The study population was predominantly female (262/362, 72.4%) and young, with a median age of 28 years (IQR 12–40). Most participants belonged to low-income households (337/362, 93.1% were either Lower or Lower Middle Income) and had no formal education (217/362, 60.0%) (Table 1).

Table 1. Sociodemographic characteristics by scabies case category (n=362).

*Total n is the sum across all categories; percentages are of n=362.

Prevalence and classification of scabies

Among 362 participants, 3 (0·8%, 95% CI 0·2–2·4) had laboratory-confirmed scabies, while 66 (18·2%, 95% CI 14·3–23·0) met criteria for probable infestation and 119 (32·9%, 95% CI 28·2–37·8) for suspected infestation. The remaining 174 (48·1%, 95% CI 42·9–53·3) were classified as non-cases (Table 2, Figure 2).

Table 2. Scabies case classification, definition and prevalence among study participants (N = 362).

*Probable and Suspected definitions exclude confirmed cases.

Household conditions and behavioral factors by scabies case status

Household crowding was more pronounced among cases. The median family size was largest for confirmed cases (11 persons; IQR 10–13), followed by probable cases (8 persons; IQR 6–11). In contrast, suspected and non-cases had smaller median family sizes of 7 (IQR 5–10) and 6 persons (IQR 4–9), respectively. A similar pattern was seen with sleeping space: confirmed cases had a median of 3 rooms (IQR 2–4), while all other groups had a median of 2 rooms (IQR 1–3). Consequently, household density was highest among cases, with a median of 4.0 persons per room (IQR 3.0–5.0) for confirmed cases and 3.5 (IQR 2.3–4.7) for probable cases, compared to 3.0 (IQR 2.0–4.0) for suspected and 2.7 (IQR 1.7–3.5) for non-cases.

Conditions that facilitate scabies transmission were widespread among cases. The vast majority of confirmed (3 of 3; 100%) and probable (64 of 66; 97%) cases reported sharing sleeping mattresses, compared to 120 of 174 (69%) non-cases. Furthermore, direct bed sharing with an infested person was common, reported by most confirmed (2 of 3; 67%), probable (63 of 66; 96%), and suspected (114 of 119; 96%) cases, but by none (0 of 174; 0%) of the non-cases.

While most participants reported good personal hygiene practices, significant environmental and economic barriers were strongly linked to case status. The need to collect water from a distant source was nearly universal among confirmed cases (3 of 3; 100%) and common among probable (35 of 66; 53%) and suspected (58 of 119; 49%) cases, but rare among non-cases (4 of 174; 2%). Most strikingly, financial or transport barriers to healthcare were reported by all confirmed cases (3 of 3; 100%), a large majority of probable cases (47 of 66; 71%), and nearly one-third of suspected cases (37 of 119; 31%), but by only 3 of 174 (2%) non-cases (Table 3).

Table 3. Household and behavioral characteristics (N = 362).

Health and nutritional status by scabies case status

Overall, underweight status (BMI <18.5 kg/m²) was common, affecting 150 (41%) of 362 participants. The prevalence of anemia, however, varied significantly across case categories, ranging from 6% in non-cases to 67% in confirmed cases. Specifically, anemia was present in two-thirds (67%) of confirmed cases, over one-third (35%) of probable cases, less than one fifth (17%) of suspected cases, and in a small minority (6%) of non-cases. Chronic immunosuppressive conditions were rare overall (4% of participants) and showed no distinct pattern by case category (0% confirmed, 5% probable, 4% suspected, 5% non-cases). As per the case definitions, all confirmed, probable, and suspected cases reported a previous skin disease, compared with a minority (21%) of non-cases (Table 4).

Table 4. Health status, comorbidities, and nutritional indicators by case status (N = 362).

* Anemia was assessed based on self-reported prior diagnosis, as hemoglobin measurements were not collected. **Based on “History of Diseases Such as Diabetes, Cancer, HIV/AIDs” and “History of Using Immunosuppressors” variables.

Multivariable analysis of risk factors associated with scabies infestation

In multivariable logistic regression comparing confirmed and probable cases (n=69) to non-cases (n=293), several factors emerged as strong, independent predictors of scabies infestation (Table 5). The risk factors associated with scabies were related to direct personal contact. Sharing a bed with an infested person carried an adjusted odds ratio (aOR) of 16.42 (95% CI 5.99–45.00, p<0.001). Sharing clothes with an infested person was also a major independent risk factor (aOR 9.85, 95% CI 4.24–22.89, p<0.001), as was mattress sharing (aOR 5.12, 95% CI 1.47–17.88, p=0.010). Household structure and poverty-related barriers were equally significant. High household crowding (≥3 persons per room) independently increased the odds of scabies nearly three-fold (aOR 2.74, 95% CI 1.44–5.23, p=0.002). Having a distant water source (>1,000m) was strongly associated with the disease (aOR 3.41, 95% CI 1.86–6.24, p<0.001), as was reporting barriers to healthcare access due to cost or transport (aOR 11.24, 95% CI 5.78–21.85, p<0.001).

Table 5. Multivariate analysis of risk factors for scabies infestation (confirmed and probable cases vs. non-cases).

† Values presented as median [interquartile range] for continuous variables.

‡ Diabetes, Cancer, HIV/AIDS, or immunosuppressant use.

Adjusted for: Age, gender, income level, education, and all variables significant in univariate analysis (p<0.10). Model fit: Hosmer-Lemeshow χ²=5.42, p=0.711; Nagelkerke R²=0.54..

OR, Odds Ratio; CI, Confidence Interval. Bold indicates statistical significance (p<0.05).

A striking clinical finding was the independent association between anemia and scabies. After adjusting for all other factors, anemic individuals had nearly a four-fold higher odds of being a case (aOR 3.68, 95% CI 1.89–7.16, p<0.001). Age also emerged as a significant factor, with each 10-year increase in age associated with 15% higher odds (aOR 1.15, 95% CI 1.01–1.32, p=0.038).

Conversely, individual hygiene practices such as bathing frequency and use of separate soap were not significantly associated with scabies in the adjusted model. Other demographic factors like gender, income, and education were also not independent predictors. The final model demonstrated excellent fit (Hosmer-Lemeshow p=0.711) and explained a substantial proportion of the variance in scabies status (Nagelkerke R²=0.54).

Discussion

This first community-based epidemiological study of scabies among internally displaced persons (IDPs) in Somaliland reveals a substantial but largely hidden burden of disease, with only three (0·83%) laboratory-confirmed cases among 362 participants. The low rate of parasitological confirmation likely reflects the well-documented insensitivity of skin scraping in field settings, particularly where low parasite density, prior treatment, or secondary infection obscures microscopic detection (1, 2, 19). When probable cases defined by characteristic symptoms plus an epidemiologicallink to an infested household contact were included, the prevalence rose to 19·1% (69/362). This 23-fold difference underscores a possible limitation of surveillance systems that rely solely on laboratory confirmation in resource-limited settings (1, 2). Our findings align with the high burdens reported in similar humanitarian contexts, such as Ethiopian (14·9%) and Sierra Leonean (25%) displacement camps (28, 31), and firmly classify scabies as a significant public health challenge in Somaliland, consistent with its designation on the WHO roadmap for neglected tropical diseases (3, 4).

The very low proportion of laboratory confirmed cases warrants careful interpretation. Although microscopy remains a gold standard, its sensitivity in field settings is limited considering sampling challenges, low mite burden and operator dependence. in this regard, reliance on clinical criteria, as recommended by the International Alliance for the Control of Scabies (ICAS) framework might introduce misclassification bias, potentially leading to overestimation of prevalence. Nonetheless, given the known limitations of laboratory confirmation in community studies, the combined use of clinical and epidemiological criteria remains appropriate for estimating disease burden in resource limited settings.

The epidemiology elucidated here moves beyond individual risk to implicate structural determinants of health. In adjusted analysis, the dominant drivers of transmission were factors of deprivation and unavoidable proximity: sharing a bed with an infested person (aOR 16·42, 95% CI 5·99–45·00), sharing clothes (aOR 9·85, 4·24–22·89), and mattress sharing (aOR 5·12, 1·47–17·88). These findings reinforce that, in settings of extreme poverty and crowding, conventional health messaging centered on personal hygiene is insufficient (7, 18). This is corroborated by the null association between scabies and self-reported bathing frequency or soap use in our multivariate model. The primary risk is not a lack of cleanliness, but a lack of space, privacy, and access to basic amenities.

Overcrowding was a fundamental, independent predictor (aOR 2·74, 1·44–5·23 for ≥3 persons per room), a finding extensively documented as the cardinal risk factor for scabies endemicity (8, 9, 11, 13). The median household density of 3·0 persons per room in our cohort—and notably 4·0 among confirmed cases creates an environment where the mite’s life cycle is easily sustained through prolonged close contact (10). This underscores that scabies is not merely an infectious disease but a direct marker of inadequate shelter and failed housing policy in displaced populations.

A novel and clinically significant finding is the strong, independent association between anemia and scabies (aOR 3·68, 1·89–7·16). While causality cannot be inferred from this cross-sectional design, the association is biologically plausible. Anemia, often a proxy for chronic malnutrition or micronutrient deficiency, may compromise epidermal integrity and cutaneous immunity, increasing susceptibility to infestation and secondary bacterial infection (15, 16). Conversely, the relentless pruritus, sleep disturbance, and social stigma of scabies can exacerbate poor nutritional intake, creating a vicious syndemic cycle that amplifies morbidity (17). This link highlights the potential benefit of integrating nutritional screening and interventions with scabies control programs.

Strikingly, financial or transport barriers to healthcare access emerged as one of the strongest risk factors (aOR 11·24, 5·78–21·85). This finding reflects a critical systems failure: when individuals cannot reach or afford care, infestation persists, households remain contagious, and community transmission escalates (12, 20). Similarly, having a distant water source (>1000 m) was independently associated with scabies (aOR 3·41, 1·86–6·24), likely acting as a proxy for overall deprivation and reduced capacity for laundry and environmental hygiene (22, 25, 29, 30).

Strengths and limitations

The principal strength of this study is its use of a pragmatic, tiered case definition that reflects the operational reality of scabies diagnosis in a complex emergency an approach advocated for neglected tropical diseases in such settings (4). The analytical rigor of multivariable modeling allowed for the identification of independent drivers amidst multiple correlated risk factors. However, the study is limited by its cross-sectional design, which prevents causal inference, particularly regarding the anemia–scabies association. It is therefore not possible to determine whether anemia predisposes individuals to scabies or arises as a consequence of infestation or related socioeconomic conditions. Longitudinal studies are required to show the direction and mechanism of this association.

Although representative of the sampled settlements, generalizability to all Somaliland IDPs may be constrained. Self-reported behaviors are subject to social desirability bias, and some misclassification within the probable case category is possible, though this reflects the inherent challenge of field diagnosis in low-resource settings.

Conclusion and implications

This first epidemiological study of scabies among internally displaced persons in Somaliland reveals a substantial burden of disease that is systematically underestimated by conventional surveillance. While only 0·8% of cases were confirmed microscopically, a clinically significant prevalence of 27·1% was identified using combined clinical and epidemiological criteria, reflecting the severe overcrowding, shared sleeping arrangements, and limited water and healthcare access that characterize humanitarian settings. The strong association between scabies and anemia highlights a syndemic interaction that exacerbates overall morbidity.

To achieve sustainable control, interventions must address the underlying structural drivers of transmission. Improving shelter conditions to reduce household density, ensuring reliable water access, and removing financial barriers to care are essential. Integrating scabies management with nutritional support could help mitigate associated anemia. Success will require moving beyond case-based approaches to confront the systemic deprivation that sustains scabies transmission a fundamental challenge for health equity in displaced populations.

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Footnotes

Edited by: Emmanuel Siddig, University of Khartoum, Sudan

Reviewed by: Katherina Alicia Vizcaychipi, Instituto Nacional de Enfermedades Infecciosas Dr. Carlos G. Malbrán (INEI), Argentina

Cassandra Bolanle Akinde, Women in Global Health, Nigeria

Mubashir Raza, Baqai Medical University, Pakistan

Footnotes

aOR, Adjusted Oddds Ratio; CI, Confidence Interval; ICAS, International Alliance for the Control of Scabies; IDPs, Internally Displaced Persons; KOH, Potassium Hydroxide; MDA, Mass Drug Administration; MOHD, Ministry of Health Development; SPSS, Statistical Package of Social Sciences; WHO, World Health Organization