Introduction

Ascaris lumbricoides (often known simply as "Ascaris"), whipworm (T. trichiura), and hookworm are examples of the intestinal worms that infect humans and are spread through contaminated soil (Ancylostoma duodenale and Necator americanus). The poorest and most destitute communities in the world are highly affected by soil transmitted helminth infections (STHI)1.

Ethiopia ranks 13th among more than 40 African countries in terms of the prevalence of each group of illnesses2. STHI, still highly prevalent in many areas of Ethiopia particularly among school children3. Children from rural communities have a higher prevalence of STHI compared to those from urban communities. Parasitic helminth infections rank as the second most common cause of outpatient morbidity in Ethiopia due to factors such as poor toilet coverage and low-quality drinking water4.

In order to stem the spread of STHI in endemic areas, the World Health Organization (WHO) advises mass drug administration (MDA) of single-dose albendazole (ABZ) to all at-risk individuals as preventative chemotherapy (deworming)5. The anti-helminthic drug ABZ is used to treat a number of parasitic worm illnesses, including trichuriasis, filiariasis, ascariasis, hookworm, trichinosis, and strongylodiasis6. The effectiveness of ABZ is commonly evaluated by qualitative and quantitative diagnostic tests for eggs or larvae in feces at an optimal post-treatment time period, depending on the species of each parasite. It is possible to gauge the decline in prevalence and intensity of STHIs by computing the cure rate (CR) and the fecal egg reduction rate (ERR) of ABZ7.

Abdominal pain, nausea, vomiting, diarrhea, and weight loss are possible signs of ascariasis. According to8, in severe situations, the worms may result in intestinal perforation, obstruction of the colon, or even death. Abdominal pain, diarrhea, bloody stools, anemia, and weight loss are signs of a whipworm infection. Infections in children can result in delayed growth and cognitive development. Malnutrition and other severe health issues can result from persistent infections9. Anemia is one of the most typical signs of a hookworm infection. Bloating, discomfort, and stomach pain can result from hookworm infections. Another typical sign of a hookworm infection is chronic diarrhea, which can cause weight loss and dehydration10.

Single-dose ABZ, utilized by the MDA programme, is successful in treating and managing infections brought on by A. lumbricoides and hookworms but ineffective in treating T. trichiura11. It is critically necessary to develop an alternate treatment strategy in order to prevent, control, and eradicate STHI as a public health problem11. With the exception of ABZ, which has shown strong efficacy against hookworm infection, other medicines exhibited minimal efficacy against T. trichiura. The fact that ABZ's potency against T. trichiura has decreased over the past 20 years is concerning. The findings demonstrate the need to intensify efforts to develop novel pharmaceutical therapeutics, with a focus on drugs that are efficient against T. trichiura12.

There are several promising drug combinations that may enhance the impact of STHI control programs on T. trichiura without compromising efficacy against A. lumbricoides and hookworm13. Although there is a downward trend in drug efficacy due to rising historical drug pressure, further research is required to pinpoint the causes of this variation and discover whether the decreased efficacy can be connected to specific elements14. Future studies should concentrate on the effectiveness of ABZ against A. lumbricoides infection and possible risk factors that affect its transmission, as well as the impact of ABZ on hookworm infection, including the dosage and timing of treatment15. Several findings from studies on the impact of ABZ on STHs suggest that its effectiveness may be waning. Due to the dismal results of treating T. trichiura with a single oral dose of ABZ, additional drugs and/or alternate regimens should be used to treat the infection. They demonstrate that there is controversy over the effectiveness of ABZ and that not all soil-transmitted helminths have responded to this treatment16. According to Hailu, Abera17, further investigations are needed concerning the efficacy of albendazole.

In Ethiopia, many studies regarding the efficacy of ABZ against STHI have been conducted in different parts of the country. However, no systematic review or meta-analysis has been done. Therefore, it is difficult to tell about ABZ efficacy at a national level. Consequently, the present systematic review and meta-analysis were conducted to determine the efficacy of ABZ against STHIs in Ethiopia at a national level.

Materials and methods

Criteria for inclusion and exclusion of studies

Research detailing the efficiency of ABZ against STHI, studies written in English, studies carried out in any year, and studies looking at ABZ's effectiveness between 14 and 21 days following therapy18, and based one WHO guide line to study the efficacy of anthelminthic drug, studies reporting more than 50 positive cases were all included in the current study18. Nevertheless, studies that were duplicated, extended analyses from an earlier study, incomplete, conducted outside of Ethiopia, or that used additional anthelminthic drugs like mebendazole, pyrantel pamoate, or levamisole against STHI were excluded.

Search strategy

The PubMed using MeSH words, Google Scholar, EMBASE, Scopus and Web of science databases were searched for articles written in English and containing the keywords: "Soil-transmitted helminths" OR "Ethiopia" OR "Efficacy" OR "Albendazole" OR "Soil-transmitted helminths" OR "Anthelminthic drug" OR "soil-transmitted helminths" OR "albendazole" combined with "A. lumbricoides," "hookworm," "A. duodenale", "N. americanus," "T. trichiura".

The electronic data search for the studies was conducted the published and available until December 30, 2022. Identification, screening, checking eligibility, and the inclusion of the relevant literature were done following the preferred reporting items for systematic reviews and meta-analyses (PRISMA)19 (Fig. 1). Articles were first screened to remove duplication by reading titles and abstracts and initially excluded if they did not specifically refer to STHI or if they were review articles. Finally, the articles were further screened by reading the full articles and were excluded if they did not investigate the efficacy of albendazole against STHI.

Fig. 1
figure 1

PRISMA flow diagram of the studies and selection. Al = A. lumbricoides, Tt = T. trichiura.

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Method of data extraction and analysis

In order to find possibly relevant research, the authors (Miseganaw Sisay, Destaw Damtaie, and Tadesse Hailu) examined the titles, abstracts, and complete texts of all identified literatures. Miseganaw Sisay uploaded all of the listed studies to Excel and extracted the data. Then Tadesse Hailu and Destaw Damtaie performed a cross-check. We requested missing or ambiguous result data from the investigators. Study attributes and factors include the authors' names, the year the work was published, the size of the drug-taking sample, the number of participants who were healed after 14 days, and the type of STH parasite that was implicated. Microsoft Excel was used to extract the cure rate, study technique, sample size, study site, study group, region of origin, and publication year of the study from the eligible studies. We looked at the ERR (the relative drop in fecal egg count) as well as the cure rate (the percentage of treated individuals who became egg-negative).

The extracted data was analyzed using meta-analysis. The meta-analysis was also performed using comprehensive meta-analysis software version 2.2 (Biostat Inc., Englewood, NJ, USA). The efficacy of ABZ against STHIs was calculated using a random-effects model at a 95% confidence interval (CI). In the subgroup analysis, the pooled efficacy of ABZ against STHs and the forest plot of the efficacy of the drug in the regions were also calculated. Heterogeneity between sub-groups was assessed using the Cochran (Q)-value, P-value, inverse variance index (I2) test, and visual inspection of the funnel plot. I2-values lower than 25%, between 25 and 50%, and above 50% were regarded as low, moderate, and high heterogeneity, respectively20. For all tests, the level of statistical significance was set at P < 0.05. Using Egger's funnel plot test (quantitative estimate) and funnel plot symmetry (qualitative estimation), the risks of publication bias across studies were evaluated.

Data quality assessment

The cure rate (CR) of a single dose of ABZ for the treatment of STHI was the main result of this review and meta-analysis. Using Jaded scoring standards, the three reviewers independently evaluated the caliber of the searched studies that were part of the review25. The three investigators jointly rechecked the quality score and had a discussion to settle any discrepancies once it had been cross-checked.

Result

Articles selected for the study

The effectiveness of ABZ against STHI in Ethiopia was the subject of 49 articles in all. One of them was discarded because it was incomplete and 11 articles were eliminated because each had less than 50 positive cases. The remaining number of articles were incorporated into the final systematic review and meta-analysis (Fig. 1).

Characteristics of the eligible studies

Table 1 presents the characteristics of the 14 studies that were meta-analyzed. Nationwide, such efficacy studies were found only in three regions: Amhara (3, 8.1%), Oromia (23, 62.2%), and Sidama (11, 29.7%). The distribution of these studies based on the STHs tested is as follows: hookworm (13, 35.2%), A. lumbricoides (12, 32.4%), and T. trichiura (12, 32.4%).

Table 1 Characteristics of the included studies investigating the efficacy of ABZ against STHs.
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The efficacy of albendazole against hookworm

A total of 1253 positive cases of hookworm (24.9%) were included in the eligible studies in Ethiopia. The efficacy of ABZ against hookworm ranged from 66.7 to 98.9%. Its pooled efficacy against hookworm was 92.2% (95% CI 86.2–98.9%) (Fig. 2).

Fig. 2
figure 2

The efficacy of ABZ against hookworm.

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Sub-group analysis of ABZ efficacy studies against hookworm by region

The efficacy of ABZ against hookworm was highest in Sidama 96.7% (95% CI 93.8–98.2%), followed by in Oromia 93.4% (95% CI 85.1–97.2%) and in Amhara 77.2% (95% CI 64.4–86.4%) in descending order (Fig. 3).

Fig. 3
figure 3

Sub-group analysis of ABZ efficacy studies against hookworm by region.

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Heterogeneity among studies reviewed for ABZ efficacy against hookworm

The 13 articles reviewed for ABZ efficacy against hookworm were highly heterogeneous (I2 = 89.42; P < 0.001) (Table 2).

Table 2 Heterogeneity of studies reviewed for ABZ efficacy against hookworm.
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Publication bias among studies reviewed for ABZ efficacy against hookworm

The studies were distributed symmetrically about the combined effect size, which showed the absence of publication bias. The dot-like structure represented the number of studies, the middle line represented the estimated value, and the diagonal line represented 95% confidence limits around the summary efficacy estimate (Fig. 4).

Fig. 4
figure 4

Funnel plot for assessing publication bias in hookworm.

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The efficacy of albendazole against A. lumbricoides

The selected articles reported 1570 positive cases (29.5%). The efficacy of ABZ against A. lumbricoides ranged from 92.5 to 99.6%. The pooled efficacy of ABZ against A. lumbricoides was 97.7% (95% CI 96.3–98.6%) (Fig. 5).

Fig. 5
figure 5

The efficacy of ABZ against Ascaris lumbricoides.

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Sub-group analysis of ABZ efficacy studies against A. lumbricoides by region

ABZ efficacy studies against A. lumbricoides were conducted only in Oromia and Sidama regions. The sub-group analysis indicates that the efficacy of ABZ against A. lumbricoides in Oromia and Sidama regions was 98.3% (95% CI 97.0–99.0%) and 96.63% (95% CI 93.2–98.3%), respectively (Fig. 6).

Fig. 6
figure 6

Sub-group analysis of ABZ efficacy studies against A. lumbricoides by region.

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Heterogeneity among studies reviewed for ABZ efficacy against A. lumbricoides

The 12 studies reviewed for ABZ efficacy against A. lumbricoides had a moderate degree of heterogeneity (I2 = 41.51%, P = 0.065) (Table 3).

Table 3 Heterogeneity of studies reviewed for ABZ efficacy against A. lumbricoides.
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Publication bias among studies reviewed for ABZ efficacy against A. lumbricoides

The studies were distributed symmetrically about the combined effect size, which showed the absence of publication bias. The dot-like structure represented the number of studies, the middle line represented the estimated value, and the diagonal line represented 95% confidence limits around the summary efficacy estimate (Fig. 7).

Fig. 7
figure 7

Funnel plot assessing the publication bias of A. lumbricoides.

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The efficacy of ABZ against T. trichiura

A total of 1647 positive cases (30.6%) were included in the eligible studies in Ethiopia. The efficacy of ABZ against T. trichiura ranged from 17.1 to 63.8%. The pooled efficacy of ABZ against T. trichiura was 38.6% (95% CI 31.0–46.9%) (Fig. 8).

Fig. 8
figure 8

The pooled efficacy of albendazole against T. trichiura.

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Sub-group analysis of ABZ efficacy studies against T. trichiura by region

Like that of A. lumbricoides, ABZ efficacy studies against T. trichiura were reported only from Oromia and Sidama regions. The sub-group analysis indicates that the efficacy of ABZ against T. trichiura in Oromia and Sidama regions was 39.0% (95% CI 30.4–48.5%) and 37.8% (95% CI 21.8–56.9%), respectively (Fig. 9).

Fig. 9
figure 9

Sub-group analysis of ABZ efficacy studies against T. trichiura by region.

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Heterogeneity among studies reviewed for ABZ efficacy against T. trichiura

It discovered significant levels of heterogeneity among the outcomes of the 12 studies that were included (I2 = 90.619%, P = 0.000) (Table 4).

Table 4 Heterogeneity of studies reviewed for ABZ efficacy against T. trichiura.
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Publication bias among studies reviewed for ABZ efficacy against T. trichiura

The studies were distributed symmetrically about the combined effect size, which showed the absence of publication bias. The dot-like structure represented the number of studies, the middle line represented the estimated value, and the diagonal line represented 95% confidence limits around the summary efficacy estimate (Fig. 10).

Fig. 10
figure 10

Funnel plot assessing the publication bias of T. trichiura.

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Discussion

In the present study, the pooled efficacy of albendazole against hookworm was 92.2% (95% CI 86.2–98.9%) in Ethiopia. According to WHO guide lines, it was satisfactory efficacious18. However, it was higher than the results reported in Nepal 74.3% and 53.3%33, in Tanzania 63–72%34, in Coted Ivoire 74.9%35, the reports in Globally from 1960 to 2016 by Moser et al. (2017) 79.5%, the reports done Globally from 1960 to August 2007 by Keiser and Utzinger36 72%, the results reported in Lao PDR 36%37. Based on WHO guide line18, the present study in line with the results reported in Rewanda 96.7%11 and in Malaysia 100%38 because all indicates satisfactory efficacious. This difference might be related with its ubiquitous nature and large levels of environmental contamination due to the extreme resistance of its egg to harsh environments, age group, brand of drug and immunization39.

In sub-group analysis, the efficacy of ABZ against hookworm in the Amhara region was 77.2% (95% CI = 64.4–86.4%). Based on WHO guide line18, it indicates reduced efficacious against hookworm in Amhara region. This result is in line with the works in Tanzania 63–72%34, in Coted I voire 74.9%35, the works done Globally from 1960 to 2016 by Moser et al. (2017) 79.5%, and the reports done Globally from 1960 to August 2007 by Keiser and Utzinger36 72%. However, it was lower than in the results reported in Rewanda 96.7%11, in Malaysia 100%38 and higher than the results reported in Nepal 53.3%33. In the Oromia region, it was 93.4% (95% CI = 85.1–97.2%). This result is higher than the results reported in Tanzania 63–72%34, in Coted I voire 74.9%35, in Nepal 74.3 and 53.3%33, and the results reported globally from 1960 to 2016 by Moser et al. (2017) 79.5%. But based on WHO guide line18, the result indicated satisfactory efficacious and this in line with the results reported in Rewanda 96.7%11, in Malaysia 100%38. In the Sidama region, it was 96.7% (95% CI = 93.8–98.2%). According to WHO fact sheet18, indicating satisfactory efficacious against hookworm. This result is higher than the results reported, in Tanzania 63–72%34, in Coted Ivoire 74.9%35, in Nepal 74.3 and 53.3%33 and the reports done Globally from 1960 to 2016 by Moser et al. (2017) 79.5%. But in line with the results reported in Rewanda 96.7%11, in Malaysia 100%38. Like the efficacy of ABZ against hookworm in Oromia, it was higher than the results reported by Moser et al. (2017), which were 79.5%. Except in the Amhara region, the present study at national and regional level showed that ABZ was more efficacious against hookworm. This result lines up with the reports conducted by Clarke, Doi13. The difference in efficacy may due to difference period of assessment between the first doses and follow up, the stage of the parasite present in the host, immune status of the participants, age group, brand of drug and might be associated with baseline infection intensity, nature of study population, sample size, and brand of the drug used.

The heterogeneity among studies reviewed for ABZ efficacy against hookworm was I2 = 89.418 percent, P < 0.001, indicating that there was a significant difference between the investigations. The result is in line with the studies conducted in globally by Palmeirim, Hürlimann40. However, the result is lower than the reports from Asia (I2 = 98%, p < 0.001)41. Publication bias among studies reviewed for ABZ efficacy against hookworm, the funnel plot used in this investigation proved effective. The equitable distribution of the studies into the plot's median alignment suggests that there was no publication bias among the research. The result of the present study of publication bias lines with the results reported by42.

The pooled efficacy of Albendazole against A. lumbricoides was 97.7% (95% CI 96.3–98.6%) in Ethiopia. According to WHO guide lines, it was satisfactory efficacious18. This result is in line with the results reported in Nepal 97% and 95%33, in Rwanda 95.1%11, in South Africa 97.2%43, in Malaysia 100%38, and in Tanzania 90–97%34, and the reports done globally by Moser et al. (2017) 95.7%. However, it was higher than the results reported in Gabon 85%44, in Rewanda 75.4%45, in Vietnam 64.9%46, and the reports done from 1960 to 2007 by Keiser and Utzinger36 88%. Like the efficacy of ABZ against hookworm, the difference might be related with its ubiquitous nature and large levels of environmental contamination due to the extreme resistance of its egg to harsh environments, age group, brand of drug and immunization39.

In sub group analysis, the efficacy of ABZ against A.lumbricoides in the Oromia region was 98.3% (95% CI = 97.0–99.0%). Based on WHO guide line, indicating satisfactory efficacious against A.lumbricoides in Oromia. This result is higher than the results reported in, in Gabon 85%44, in Vietnam 64.9%46, and in Rewanda75.4%45, and India (East Sikkim) 55.5%47. However, based on WHO guide line18,the result in line with the results reported in Nepal 97% and 95%44, in Rewanda 95.1%11, in South Africa 97.2%43, in Malaysia 100%38, and the results reported globally from 1960 to 2016 by Moser et al. (2017) 95.7%,. In the Sidama region, it was 96.6% (95% CI = 93.2–98.3%). According to WHO guide line18, it indicates satisfactory efficacious. This result is higher than the results reported in India (East Sikkim) 55.5%47, in Gabon 85%44, in Vietnam 64.9%46, and in Rewanda75.445 . However, based on WHO guide line, it agrees with in the results reported in Nepal 97% and 95%44, in Rewanda 95.1%11, in South Africa 97.2%43, in Malaysia 100%38, and the results reported globally from 1960 to 2016 by Moser et al. (2017) 95.7%. The variation in efficacy could be attributed to various factors such as the duration of assessment between the initial dose and subsequent visits, the stage at which the parasite is present in the host, the participants' immune status, age group, drug brand, and possible correlations with baseline infection intensity, study population characteristics, sample size, and drug brand.

The heterogeneity among studies reviewed for ABZ efficacy against A.lumbricoides was I2 = 41.5 percent, P = 0.065, indicating that there was no significant difference between the investigations. The result is in line with the studies conducted globally by Palmeirim, Hürlimann40. However, the result is lower than the reports from Asia (I2 = 91%, p < 0.001)41. Publication bias among studies reviewed for ABZ efficacy against A.lumbricoides, the funnel plot used in this investigation proved effective. The equitable distribution of the studies into the plot's median alignment suggests that there was no publication bias among the research42.

The pooled efficacy of albendazole against T. trichiura in the present study was 38.6% (95% CI 31.0–46.9%). Based on WHO guide line18, the present study indicates reduced efficacy against T.trichiura. This result is in line with the results reported by Moser et al. (2017) 30.7%. However it was higher than in Tanzania 6–9%34, and in Rewanada 17.6%11 and lower than in Zanzibar 40%48, in South Africa 46.0%43, and in Malaysia 64.6%38, and in Northern Honduras 47.7%49. Like the efficacy of ABZ against hookworm and A.lumbricoides, the difference might be related with its ubiquitous nature and large levels of environmental contamination due to the extreme resistance of its egg to harsh environments, age group, brand of drug and immunization39.

In subgroup analysis, the efficacy of ABZ against T. trichiura in the Oromia and Sidama region were 39.0% (95% CI = 30.4–48.5%) and 37.8% (95% CI = 21.8–56.9%) respectively. So, according to WHO guide line18, indicating reduced efficacy against T. trichiura. This result agrees with the results reported by Moser et al. (2017) 30.7%. However it was higher than in Tanzania 6–9%34, and in Rewanada 17.6%11 and lower than in Northern Honduras 47.7%49, in Zanzibar 40%48, in South Africa 46.0%43, and in Malaysia 64.6%38. In the present study, the efficacy of ABZ against T. trichiura suggests less efficacious issues, such as drug resistance. This finding supports by41. The variations in the duration of evaluation between the initial dosages and the follow-up, the stage at which the parasite is present in the host, the participants' immune status, age group, and drug brand, as well as the nature of the study population, sample size, and drug brand, may all contribute to the disparity in efficacy.

The heterogeneity among studies reviewed for ABZ efficacy against T. trichiura was I2 = 90.6 percent, P < 0.001, indicating that there was a significant difference between the investigations. The result is in line with the studies conducted globally by Palmeirim, Hürlimann40. However, the result is higher than the result reported from Asia (I2 = 79%, p < 0.001)41. Publication bias among studies reviewed for ABZ efficacy against T. trichiura, the funnel plot used in this investigation proved effective. The equitable distribution of the studies into the plot's median alignment suggests that there was no publication bias among the research42.

By giving deworming medication to all susceptible groups in a designated area to lessen the burden of infection, this study may be implicated. Coordinating and communicating regularly can help with case referrals, treatment follow-up, and the distribution of health education resources. Encourage the incorporation of intestinal parasite prevention strategies into national health programs and provide sufficient resources for their execution. This will guarantee the viability of deworming initiatives and facilitate their inclusion into the current healthcare systems.

Conclusion and recommendations

The results of this systematic review and meta-analysis demonstrated that in Ethiopia, ABZ at the recommended dose of 400 mg had promise efficacy against STH infections, including hookworm and A. lumbricoides, but not T. trichiura. The review revealed that using ABZ to treat STH infection led to a high cure rate for hookworm and A. lumbricoides, but a lower cure rate for T. trichiura. Oromia and Sidama national regional states had greater ABZ cure rates for hookworm and A. lumbricoides infections, while Amhara national regional state had lower ABZ cure rates. In every part of the nation, the cure rate for T. trichiura with ABZ was lower. The medication’s efficacy varied greatly from trial to research and from region to region, indicating the necessity of routinely assessing the medication at both the regional and national levels to meet the objective of eradicating pediatric STH infection-related morbidity and mortality. Therefore, albendazole can be used as a treatment for hookworm and A. lumbricoides at national and regional level except Amhara region. Further investigation will be needed in Amhara region about the efficacy of ABZ against hookworm. However, an alternative drug should be searched for T. trichiura at national and regional level. For policy making, advocate for the inclusion of intestinal parasite control measures in national health policies and allocate adequate funding for implementation. This will support the integration of deworming programs into existing healthcare systems and ensure their sustainability.

Limitations

A pooled cure rate was generated by this meta-analysis, which also reviewed the nation's albendazole efficacy research. It is, however, limited in several ways. A control group or people taking a placebo during the intervention period are absent from the research that made up this meta-analysis, to start. Relative risk and the risk ratio (RR) cannot be calculated as a result. The cure rate had to be used in place of the risk ratio as a result. Secondly, the research that qualified for this meta-analysis included three distinct parasitological techniques (Kato-Katz, qPCR, Mac Master, and mini-FLOTAC). The conclusions about albendazole efficacy may be impacted by the sensitivity and specificity of these approaches. Finally, not every paper that qualified for our investigation disclosed the negative consequences of albendazole. Finally, the published articles were only available in English as well as using a limited database.