Prevalence and species distribution of intestinal parasites: a four-year retrospective study at Burao general hospital, Somaliland

Abstract

Objective

This study aimed to determine the prevalence and species distribution of intestinal parasites through a four-year retrospective analysis at Burao General Hospital in Somaliland, to provide insights into the local epidemiological landscape and inform targeted interventions and resource allocation for disease control.

Results

Giardia intestinalis (57.81%) and Entameba histolytica/E. dispar (41.85%) were the most prevalent parasites. Males showed higher infection rates than females, particularly G. intestinalis and E. histolytica/E. dispar. The 15–22-year age group had the highest prevalence of both the parasites. A statistically significant association was found between sex and intestinal parasite infection (p = 0.014) but not between age and infection (p = 0.113). The prevalence of intestinal parasites fluctuated slightly over the four-year period, with the highest number of cases reported in 2024. Some parasites, such as Hymenolepis nana and the hookworm, showed a declining trend over the years.

Introduction

The global burden of intestinal parasitic infections remains a significant public health concern, particularly in developing countries [1–4]. These infections, caused by a diverse array of protozoa and helminths, can lead to malnutrition, impaired cognitive development, and reduced work productivity, affecting millions of people worldwide [5–8]. In Somaliland, limited data exists on the prevalence and distribution of intestinal parasites, hampering the implementation of effective control strategies.

This study aimed to address this knowledge gap by conducting a comprehensive four-year retrospective analysis of intestinal parasitic infections at Burao General Hospital, the primary healthcare facility in the Togdheer region of Somaliland. By examining the prevalence and species distribution of intestinal parasites, we sought to provide valuable insights into the local epidemiological landscape that could inform targeted interventions and resource allocation for parasitic disease control.

The significance of this research lies in its potential to contribute to the understanding of parasitic disease burden in regions where such information is scarce. By analyzing data from a four-year period, we aimed to identify trends, seasonal variations, and demographic patterns in parasitic infections, which could prove crucial for developing evidence-based public health policies. Furthermore, this study may serve as a foundation for future research on the impact of socioeconomic factors, environmental conditions, and healthcare practices on intestinal parasitic infections in Somaliland and similar resource-limited settings.

Methods

Study design, period, and area

This study employed a retrospective design, analyzing data collected over a four-year period from 2021 to 2024 at Burao General Hospital, located in the Togdheer region of Somaliland. The Burao General Hospital serves as the primary healthcare facility for the region, providing a representative sample of the local population.

Study participants and data collection

The study participants were individuals who presented to Burao General Hospital with symptoms suggestive of intestinal parasitic infections. Common symptoms that led to suspicion of infection and subsequent stool testing included abdominal pain, diarrhea, bloating, nausea, weight loss, and changes in stool consistency. These symptomatic patients provided stool samples for laboratory diagnoses during the study period. These samples were collected in labelled, clean, dry, leak-proof, and sterile plastic containers. Sociodemographic information and laboratory results were extracted from the laboratory registration book by using a purpose-designed worksheet.

Data processing and analysis

Stool samples were processed and examined using the saline wet mount technique, following the standard operating procedure of the health center. Direct stool examinations were conducted within 30 min of sample collection. The primary focus was to identify common intestinal parasites, including Entamoeba histolytica/E. dispar (due to morphological indistinguishability on wet mount), Giardia intestinalis, Ascaris lumbricoides, Hookworm, Trichuris trichiura, Hymenolepis nana, Taenia species, and suspected Cryptosporidium spp. No additional staining techniques (e.g., modified Ziehl–Neelsen) or antigen detection assays were performed; thus, identifications of E. histolytica/E. dispar and suspected Cryptosporidium spp. were considered presumptive based on their morphology alone. Positive samples were recorded, and the patients were treated according to the national guidelines.

The prevalence of each parasitic species was calculated as the percentage of positive samples out of the total number of samples examined. Data were stratified by age, sex, and time of year to identify potential patterns or trends in the parasite distribution. Statistical analyses were performed using STATA version 17. Descriptive statistics were used to summarize the demographic characteristics of the study population and overall prevalence of intestinal parasites. A Chi-square test was used to compare the proportion of intestinal parasite isolates with the patients’ demographic information. Statistical significance was set at P < 0.05. To assess temporal trends, annual and seasonal prevalence rates were calculated and compared across the four-year study period.

Results

Distribution of different intestinal parasite species in relation to sex and age groups

During the study period (2021–2024), 10,443 stool samples were requested for diagnosis of intestinal parasites in the study area. Of the patients requested, 7,140 (68.37%) were male and 3,303 (31.63%) were female. During the study period, the overall prevalence of intestinal parasites was 3,918/10,443 (37.51%).

The most commonly identified parasites were G. intestinalis and E. histolytica/E. dispar, with prevalence rates of 57.81% and 41.85%, respectively. Other identified parasites included Ascaris lumbricoides, T. trichiura, H. nana, Hookworm, Taenia species, Schistosoma mansoni, and suspected Cryptosporidium spp. (Table 1). The prevalence of each species varied according to sex and age. G. intestinalis and E. histolytica/E. dispar were more common in males (68.17% and 71.22%, respectively) than in females (31.83% and 28.78%, respectively). Regarding the age distribution, the highest prevalence of G. intestinalis was found in individuals aged 15–22 years (36.20%), whereas E. histolytica/E. dispar was most frequent in the same age group (38.60%).

Table 1.

Distribution of different intestinal parasite species in relation to sex and age groups

Name of the parasites	Sex (No %)			Gender (No %)
	Female	Male	Total	2–14	15–22	23–30	31–38	39–46	47–54	> 55	Total
Ascaris lumbricoides	0(0.00%)	2(100%)	2(100%)	0 (0.00%)	1 (50%)	0 (0.00%)	0 (0.00%)	1(50%)	0 (0.00%)	0 (0.00%)	2(0.05%)
Trichuris trichiura	2(100%)	0(0.00%)	2(100%)	0 (0.00%)	0 (0.00%)	1(50%)	0 (0.00%)	1(50%)	0 (0.00%)	0 (0.00%)	4(0.10%)
Hookworm (Ancylostoma)	2(100%)	0(0.00%)	2(100%)	0 (0.00%)	0 (0.00%)	1(50%)	0 (0.00%)	0 (0.00%)	0 (0.00%)	1(50%)	2(0.05%)
Schistosoma mansoni	1(100%)	0(0.00%)	1(100%)	1(100%)	0 (0.00%)	0 (0.00%)	0 (0.00%)	0 (0.00%)	0 (0.00%)	0 (0.00%)	1(0.02%)
Hymenolepis nana	1(25%)	3(75%)	4(0.10%)	1(25%)	0 (0.00%)	0 (0.00%)	2(50%)	1(25%)	0 (0.00%)	0 (0.00%)	4(0.10%%)
Taenia species	0(0.00%)	1(100%)	1(100%)	1(100%)	0 (0.00%)	0 (0.00%)	0 (0.00%)	0 (0.00%)	0 (0.00%)	0 (0.00%)	1(0.02%)
Giardia intestinalis	721(31.83%)	1544(68.17%)	2265(57.81%)	605 (26.71%)	820(36.20%)	318(14.04%)	229(10.11%)	122(5.39%)	72(3.18%)	99(4.37%)	2165(55.25%)
E. histolytica/E. dispar	472(28.78%)	1168(71.22%)	1640(41.85%)	423 (25.79%)	633(38.60%)	250(15.24%)	150(9.15)	80(4.88%)	44(2.68%)	60(3.66%)	1640(41.85%)
suspected Cryptosporidium spp	1(100%)	0(0.00%)	1(100%)	1(100%)	0 (0.00%)	0 (0.00%)	0 (0.00%)	0 (0.00%)	0 (0.00%)	0 (0.00%)	3(0.07%)
Total	1200 (30.63%)	2718(69.37%)	3918 (100%)	1032(26.34%)	1454(37.11%)	570(14.55%)	381(9.72%)	205(5.23%)	116(2.96%)	160(4.08%	3918(100%)

Compared to other intestinal parasites, G. intestinalis, Hymenolepis nana, and E. histolytica/E. Dispars were more prevalent among younger individuals. G. intestinalis had the highest prevalence among the 2–14 age group (26.71%), while H. nana showed a notable presence in the 2–14 and 31–38 age groups. Similarly, E. histolytica/E. dispar was the most frequent in the 15–22 years age group (38.60%).

In contrast, A. lumbricoides and T. trichiura were detected in small numbers, primarily in the 15–22 and 23–30 year age groups. S. mansoni was found in a single patient in the 2–14 age group. Hookworms and Taenia species were observed across various age groups but in very low numbers. Notably, suspected Cryptosporidium spp. were detected in only one individual in the 2–14 age group (Table 1).

Association between demographics and intestinal parasite infection

The chi-square test results indicated a statistically significant association between sex and intestinal parasite infection (χ2 = 19.1546, df = 8, p = 0.014). Among the infected individuals, 2,718/3,918 (69.37%) were male while 1,200/3,918 (30.63%) were female. However, there was no statistically significant difference in the distribution of intestinal parasitic infections across different age groups (χ2 = 60.09, df = 48, p = 0.113) (Table 2).

Table 2.

Association between demographics and intestinal parasite infection

Demographic	Chi-Square Value (χ²)	Degrees of Freedom (df)	p-Value
Age	60.09	48	0.113
Sex	19.1546	8	0.014*

Trends of intestinal parasite prevalence at Burao general hospital

A slightly fluctuating trend was observed in the prevalence of intestinal parasites throughout the study period. The highest number of laboratory-confirmed cases was reported in 2024 (2,341; 59.75%), whereas the lowest was observed in 2021 (324; 8.27%) (Fig. 1). Over the years, a decline in the prevalence of some parasites, such as H. nana, Hookworm, and Taenia species, was observed, while G. intestinalis and E. histolytica/E. dispar remained consistently dominant (Fig. 1).

Fig. 1.

Trends of Intestinal Parasite Prevalence at Burao General Hospital

Prevalence of parasite species in different years

Regarding the prevalence of individual parasite species across the study period, G. intestinalis and E. histolytica/E. dispar were dominant in 2024, whereas H. nana, Hookworm, and Taenia species were very few in 2022, 2023, and 2024, showing a significant decline. Similarly, S. mansoni and suspected Cryptosporidium spp. were detected only in 2022 and 2023, respectively, indicating a very low but persistent presence (Fig. 2).

Fig. 2.

Prevalence of Parasite Species in Different Years

Discussion

The results of this four-year retrospective study at Burao General Hospital in Somaliland provide valuable insights into the prevalence and distribution of intestinal parasites in the region. These findings reveal a significant burden of parasitic infections, including G. intestinalis and E. histolytica/E. dispar emerging as the predominant species. These results have important implications for public health strategies and clinical practice in Somaliland and potentially in similar resource-limited settings.

The high prevalence of G. intestinalis (57.81%) and the presumptive E. histolytica/E. dispar (41.85%) underscores the persistent challenge of protozoan infections in the region. This finding aligns with previous studies in developing countries, where these parasites are often reported to be major contributors to intestinal infections [1, 2]. The predominance of these protozoa may be attributed to their resilience under diverse environmental conditions and their efficient transmission through contaminated water and food sources, which are common issues in resource-limited settings.

Interestingly, our study revealed a higher prevalence of intestinal parasites among males than females, particularly G. intestinalis and E. histolytica/E. dispar. This finding is supported by other studies [9] but contradicted by other studies [10–12]. This gender disparity, confirmed by the statistically significant association in the chi-square analysis, suggests that males may be more exposed to risk factors for parasitic infections. This could be due to occupational hazards, differences in hygiene practices, or other sociocultural factors influencing parasite exposure. Further research is needed to elucidate the specific reasons for this sex-based difference, as it could inform targeted interventions.

Age-related distribution of parasites, with the highest prevalence observed in the 15–22 year age group for both G. intestinalis and E. histolytica/E. dispar is intriguing [13–16]. Although the overall association between age and infection is not significant, this trend warrants further investigation. This may reflect age-specific behaviors or exposures that increase the risk of infection in this particular age group. Understanding these factors may be crucial for the development of age-appropriate prevention strategies.

The lower prevalence of helminth infections, such as A. lumbricoides and T. trichiura, compared to protozoan infections is noteworthy, which contradicts other studies [17, 18]. This pattern may reflect the success of deworming programs or changes in environmental conditions that are less favorable for helminth transmission. However, the persistent, albeit low, presence of these parasites indicates the need for continued vigilance and control.

The detection of S. mansoni and suspected Cryptosporidium spp., albeit in very low numbers, highlights the diversity of the parasitic infections in this region. These findings emphasize the importance of maintaining broad diagnostic capabilities to detect less common parasites that may have significant health impacts.

The slightly fluctuating trend in intestinal parasite prevalence over the four-year period, with the highest number of cases reported in 2024, suggests that parasitic infections remain a persistent problem. This trend could be influenced by various factors, including changes in environmental conditions, population movements, and variations in healthcare-seeking behaviors. A decline in some parasites (for example, H. nana, Hookworm, and Taenia species) over the years may indicate the effectiveness of specific control measures or changes in risk factors for these parasites.

Our study has several strengths, including its large sample size, extended study period, and comprehensive coverage of multiple parasitic species. These factors enhance the reliability and generalizability of the findings. The use of standardized diagnostic techniques and the inclusion of sociodemographic data allows for a better understanding of parasitic infection patterns in the population.

However, we acknowledge the limitations of the study design. As this was a retrospective analysis based on hospital data, our findings may not fully represent the community-wide prevalence of intestinal parasites. There was a potential for selection bias because only individuals who sought medical care and provided stool samples were included in this study. Additionally, the use of a single stool examination technique may have underestimated the true prevalence of some parasites, particularly those with intermittent shedding patterns. A key limitation of this study was the reliance on saline wet-mount microscopy for parasite identification. This technique does not allow for definitive differentiation between E. histolytica and E. dispar, or conclusive identification of Cryptosporidium species. Future studies should incorporate additional diagnostic methods such as antigen detection or molecular techniques to confirm species-level identifications.

Despite these limitations, our findings have significant implications for public health policies and clinical practice in Somaliland. The high prevalence of protozoan infections calls for targeted interventions focusing on improving water quality, sanitation, and hygiene practices. The observed gender- and age-related patterns suggest the need for tailored health education programs and preventive measures for specific demographic groups.

Future research should include community-based surveys to obtain a more comprehensive picture of the prevalence of parasitic infections, including in asymptomatic carriers. Investigations into the risk factors associated with observed sex and age disparities would be valuable. Studies of the impact of these infections on nutritional status, cognitive development, and work productivity in a local context would further elucidate the public health significance of these findings.

Conclusion

This study provides crucial epidemiological data on intestinal parasitic infections in Somaliland, highlighting the persistent challenges posed by protozoan parasites, particularly G. intestinalis, and the presumptive E. histolytica/E. dispar. These findings underscore the need for continued efforts in parasite control with a focus on improving diagnostic capabilities, implementing targeted interventions, and addressing sex-specific risk factors. This study contributes to the growing body of knowledge on parasitic infections in resource-limited settings, and provides a foundation for evidence-based public health strategies in Somaliland and other similar regions.

Abbreviations

A. lumbricoides

Ascaris lumbricoides

Entamoeba histolytica/E. dispar

Entamoeba histolytica / Entamoeba dispar

G. intestinalis

Giardia intestinalis

H. nana

Hymenolepis nana

S. mansoni

Schistosoma mansoni

Spp

species

T. trichiura

Trichuris trichiura

Author contributions

The study was conceptualised and designed by DKY, who served as both the principal investigator and corresponding author, gathered and examined the data, interpreted the findings, composed the initial draft, and critically evaluated and endorsed the final manuscript. ASI, MAH, HAH, MFM, CMJ, AMA, HAE, BAS, and JAS contributed to the data collection and manuscript review. All authors reviewed the manuscript, agreed to the target journal for submission, and accepted responsibility for all aspects of this study.

Funding

Not applicable.

Data availability

The datasets utilized in this study were not publicly accessible because of privacy concerns. However, interested parties may contact the corresponding author to request access to the data, thereby supporting the findings presented herein. These requests were evaluated on a case-by-case basis.

Data availability

The datasets utilized in this study were not publicly accessible because of privacy concerns. However, interested parties may contact the corresponding author to request access to the data, thereby supporting the findings presented herein. These requests were evaluated on a case-by-case basis.

Declarations

Ethics approval and consent to participate

This study was approved by the Ethics Review Committee (ERC) of the University of Burao School of Postgraduate Studies and Research. The ERC waived the requirement for informed consent owing to the retrospective nature of the study and the use of existing de-identified data under the approval number (Ref. No. UoB/SPGSR/45/2025). The study was conducted in accordance with relevant ethical guidelines and regulations.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.