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. 2020 Dec 11;15(12):e0243836. doi: 10.1371/journal.pone.0243836

Determinants of soil-transmitted helminth infections among pre-school-aged children in Gamo Gofa zone, Southern Ethiopia: A case-control study

Mekuria Asnakew Asfaw 1,*, Teklu Wegayehu 2, Tigist Gezmu 1, Alemayehu Bekele 1, Zeleke Hailemariam 3, Teshome Gebre 4
Editor: Kebede Deribe5
PMCID: PMC7732061  PMID: 33306738

Abstract

Background

Pre-school aged children (PSAC) are highly affected by soil-transmitted helminths (STH), particularly in areas where water, sanitation, and hygiene (WASH) are inadequate. Context-specific evidence on determinants of STH infections in PSAC has not been well established in the study area. This study, therefore, aimed to fill these gaps in Gamo Gofa zone, Southern Ethiopia.

Methods

A community-based unmatched case-control study, nested in a cross-sectional survey, was conducted in January 2019. Cases and controls were identified based on any STH infection status using the Kato-Katz technique in stool sample examination. Data on social, demographic, economic, behavioral, and WASH related variables were collected from primary caregivers of children using pre-tested questionnaire. Determinants of STH infections were identified using multivariable logistic regression model using SPSS version 25.

Results

A total of 1206 PSAC (402 cases and 804 controls) participated in this study. Our study showed that the odds of STH infection were lowest among PSAC living in urban areas (AOR = 0.55, 95% CI: 0.39–0.79), among those from households with safe water source (AOR = 0.67, 95% CI: 0.47–0.0.93), and in those PSAC from households with shorter distance from water source (<30 minutes) (AOR = 0.51, 95% CI: 0.39–0.67). On the other hand, the odds of STH infection were highest among PSAC from households that had no functional hand washing facility (AOR = 1.36, 95% CI: 1.04–1.77), in those PSAC from households that had unclean latrine (AOR: 1.82, 95% CI: 1.19–2.78), and among those PSAC under caregivers who had lower score (≤5) on knowledge related to STH transmission (AOR = 1.85, 95% CI: 1.13–3.01).

Conclusions

Given efforts required eliminating STH by 2030; the existing preventive chemotherapy intervention should be substantially strengthened with WASH and behavioral interventions. Thus, an urgent call for action is required to integrate context-specific interventions, particularly in rural areas.

Introduction

According to the World Health Organization (WHO) estimate, soil-transmitted helminths (STH), including Ascaris lumbricoides, trichuris trichiura, and hookworms, affect more than 2 billion people worldwide [1]. It is known that pre-school aged children (PSAC) (1–5 years) account for significant proportion (10%-20%) of the people affected with STH [2, 3]. STH infections among children have adverse health outcomes, such as anaemia, malnutrition [4], stunting [5], and cognitive impairment [6]. In Ethiopia, STH are among the most prevalent Neglected Tropical Diseases (NTDs), with about 81 million people living in STH endemic areas, of which 9.1 million are PSAC [7]. Infections with STH are primarily linked with poverty, with the highest prevalence rates found in developing countries, where hygiene and sanitation are absent or inadequate, and access to safe, clean water is insufficient and inaccessible [6, 8–10].

Preventive chemotherapy, deworming, using annual or biannual single-dose albendazole (400 mg) or mebendazole (500 mg) is recommended by the WHO as a public health intervention against STH [11]. It has been provided for PSAC as one of the high risk group for many years in endemic countries including Ethiopia in areas where the baseline prevalence of any STH infection is 20% or higher among children in order to control and eliminate STH [1, 7, 11]. Since 2005, Ethiopia has been applying mass drug administration (MDA) against STH to a large number of PSAC, with coverage of 78% in 2009 [1]. However, treatment only does not halt the cycle of transmission. Evidences suggest that improvements of Water, Sanitation and Hygiene (WASH) infrastructures and appropriate health seeking behavior are indispensable to achieve sustained control and elimination of STH [12, 13]. Fortunately, a recent development of the WASH–NTD joint strategy provides an entrance point and guidance for improved communication, coordination, and collaboration [14].

To sustain the achievements made by deworming activities, and eliminate STH by 2030 (<2% proportion of STH infections of moderate and heavy intensities), previous study and WHO’s road map recommend context-specific WASH interventions [15, 16]; this is due to the fact that the association between WASH and STH infection is complex. Although there is an increased emphasis on the role of WASH on STH control, evidence gaps still exist in our understanding of the association between WASH and STH infection in Ethiopia—there is paucity of evidences regarding context-specific risk factors associated with STH infections in pre-school aged children. In addition, previous studies conducted in Ethiopia are cross-sectional, which had limitation in terms of identifying determinants of STH infections. This study, therefore, aimed to identify determinants of STH infections in PSAC in Gamo Gofa zone, Southern Ethiopia.

Methods

Study setting

This study was conducted in five districts of the former Gamo Gofa zone, in the Southern Nations, Nationalities, and Peoples’ Regional State of Ethiopia. The zone had 15 districts and two city administrations. A total of 2,043,668 people (1, 013,533 males and 1,030,135 females) live in the zone, according to the 2007 census and projections of Central Statistical Agency of Ethiopia [17]. It is known that STH is endemic in the zone [7].

Study design and period

A community based unmatched case-control study, which was nested in a community based cross-sectional survey, was conducted in January 2019. First, cases (a group known to have STH infection) and controls (a group known to be free of the STH infection) were identified, and then traced back to investigate exposures to potential risk factors.

Source and study populations

The source population was all PSAC in Gamo Gofa zone, and the study population (cases and controls) was all selected PSAC in the selected STH endemic kebeles (localities). Since there is no consistent definition for PSAC in current literatures, all children aged 1 to 5 years who are not yet attending primary school were considered as pre-school aged children, as supported by WHO guideline [18].

Inclusion and exclusion criteria

Cases and controls were selected irrespective of infection intensity. Some eligible children were excluded in the event when caregivers were unavailable to provide their information.

Sample size estimation

The sample size was determined using double proportion formula, using Open Epi version 2.3.1, by considering the following into considerations: 80% power; ratio of controls to cases (2:1); two-sided confidence level (1-α); 95% confidence interval; prevalence of exposure among cases (6.16%), and prevalence of exposure among controls (2.58) [19]; hence we estimated a sample size of 402 cases and 804 controls.

Sampling strategy

Both cases and controls were systematically selected from 5 districts of the zone by taking probability proportional-to-population size into account based on the number of cases in the cross-sectional study [20]; which was conducted ahead of this study in the same study area (Table 1).

Table 1. Sampling technique.

Category Districts Total sample size
Deremalo Chencha Dita Demba Gofa Bonke
Cases 61 145 76 30 90 402
Controls 122 292 152 59 179 804
Total 183 437 228 89 269 1206
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Study variables

In this study, STH infection status (positive or negative for any STH) was the outcome variable, and the independent variables were socio-demographic and economic factors; child factors; receiving deworming treatment in the last year; WASH factors, and knowledge and practice (KP) of caregivers on transmission and prevention of STH.

Data collection and Kato-Katz technique

Data and stool collection

Data on risk factors were collected by trained health professionals using standardized and pre-tested paper based questionnaire through face-to-face interviews. Stool samples were examined using the Kato-Katz technique to determine infection status. The stool samples were collected using clean, leak proof and screw cup container, and transported to nearby health facility using an ice-boxes with frozen ice-packs. The specimens were processed within two hours of receipt or kept in an ice-box where travel time exceeded two hours.

Kato-Katz technique

The Kato–Katz technique is the diagnostic method recommended by WHO for monitoring large-scale treatment programmes implemented for the control of STH infections. It was performed as follow: A small amount of stool sample was pressed through a sieve to remove large particles. Part of the sieved stool was then transferred to the hole of a template on a slide using flat-sided spatula. The hole was filled; the template was removed; and the remaining sieved sample was covered with cellophane which had been pre-soaked in glycerol. Then, the microscope slides were inverted and the fecal samples were firmly pressed against the hydrophilic cellophane strip on another microscope slide or on a smooth hard surface. The fecal material was spread evenly between the microscope slide and the cellophane strip; it should be possible to read newspaper print through the smear after clarification. The slide was carefully removed by gently sliding it sideways to avoid separating the cellophane strip or lifting it off. Then, the slide was placed on the bench with the cellophane upwards, and water evaporates while glycerol clears the smear. Finally, the smears were examined in a systematic manner and the number of eggs of each species reported. Later multiply by 24 (for a 41.7 mg template) to give the number of eggs per gram of stool [21].

Data quality control

Data quality was ensured by standard operational procedure and close monitoring of data collection process by supervisors. In addition, two slides were prepared for each stool sample in order to increase positive predictive value, and bench aids (pictures of parasites eggs) were displayed on wall, in front of microscopy examination for the purpose of internal reference.

Data analysis and measurement

A sample size of 1206 participants (402 cases and 804 controls) included to provide 80% power at P <0.05 to detect risk of any STH infections. First, data were edited, coded and entered into EpiData 4.4.2, and then exported to SPSS software (IBM, version 25) for analysis. Second, goodness of model fitness, interaction effect, multi-collinearity (correlation coefficient <0.90), and assumption of Chi-Square test were checked before fitting into multivariable model.

Household’s wealth status was computed using principal component analysis, and quintiles of wealth index were created to observe the presence of association with STH infection status. Score out of 11/12 variables’ response was computed to determine knowledge and practice of caregivers on STH transmission and prevention by counting value within a case (1 = Yes and 0 = No). In this study, latrine cleanliness was stated as absence of faecal material or any dirt on the upper surface/floor of the latrine, and unsafe water was defined as untreated water obtained from well, river and spring, whereas safe water defined as water obtained from private or public tap water.

Finally, all potential variables with P ≤0.25 with the outcome variable were entered into multivariable logistic regression model using backward stepwise method to identify determinants of STH infections. P-value <0.05 was considered as statistically significant, and odds ratio at 95% confidence interval was indicated as the precision and strength of association.

Ethics statement

The study was reviewed and approved by Institutional Research Ethics Review Board of Arba Minch University (reference number: CMHS/11222/111). Oral and written consents were received from district administrators and head of households. Assent was not obtained from PSAC since we believe that caregivers are responsible on behalf of them. Children tested positive for STH were treated with albendazole or mebendazole by health professionals at the end of the study.

Results

Socio-demographic and economic characteristics

Nearly 45% (181/402) of cases and 49.3% (396/804) of controls were females; 33.8% (136/402) of cases and 32.1% (258/804) of controls were ≤2 years, and 42.8% (172/402) of cases and 46. 4% (373/804) of controls their caregivers did not read and write (Table 2). Details on socio-demographic and economic characteristics are presented in Table 2.

Table 2. Socio-demographic characteristics of PSAC and caregivers and economic characteristics of households in Gamo Gofa zone, Southern Ethiopia, January, 2019.

Variables Category Cases (n = 402) Controls (n = 804)
Frequency % Frequency %
Children’s sex Male 221 55.0 408 50.7
Female 181 45.0 396 49.3
Children’s age (years) ≤2 136 33.8 258 32.1
3–5 266 66.2 546 67.9
Caregivers’ age (years) <20 12 3.0 16 2.0
20–29 133 33.1 318 39.5
30–39 229 57.0 431 53.6
40–49 23 5.7 35 4.4
≥50 5 1.2 4 0.5
Place of residence Urban 51 12.7 202 25.1
Rural 351 87.3 602 74.9
Started education No 339 84.3 646 80.4
Yes 63 15.7 158 19.6
Number of household members ≤5 200 49.7 415 51.6
>5 202 50.3 389 48.4
Caregiver’s occupation Farming 261 64.9 477 59.3
Government employee 16 4.0 54 6.7
Merchant 67 16.7 166 20.6
Unemployed 47 11.7 96 12.0
Other* 11 2.7 11 1.4
Caregiver’s educations status Can’t read and write 172 42.8 373 46.4
Can read and write 84 20.9 106 13.2
Elementary 100 24.9 210 26.1
Secondary 39 9.7 81 10.1
Diploma and above 7 1.7 34 4.2
Quintile of wealth index Highest 82 20.4 160 20.0
Fourth 70 17.4 170 21.1
Middle 91 22.6 156 19.4
Second 83 20.7 152 18.9
Lowest 76 18.9 166 20.6
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* = Daily laborer and housewife

Infection status by STH species

A total of 804 controls and 402 cases participated in this study. With regard to infection status by each individual STH species, overall, ascariasis was the most prevalent (27.7%), followed by trichiurasis (11.9%) and hookworms (4.6%), and 8% PSAC were infected with two STH species (ascariasis and trichiurasis).

Univariable and multivariable analyses of factors related to STH infections

During univariable analysis, 16 variables were identified with p-value ≤0.25 in relation to STH infection status, such as place of residence, children’s age, age of caregiver, source of water, treat water, distance from water source, latrine cleanliness, faeces or any dirt observed on latrine floor, having functional hand washing facility, washing fruits or vegetables before eating, habit of washing hand after cleaning child, child hand washing habit before meal, child hand washing habit after defecation, attending nursery school (started education), caregiver’s mean score on knowledge of STH transmission and mean score on knowledge and practice of prevention of STH.

The variables with P ≤0.25 in univariable logistic regression model were entered into multivariable logistic regression model using the backward stepwise method. The reason for using p ≤0.25 was to improve the chances of remaining potential variables in the multivariable model. After adjusting for potential confounders, the model identified the following variables as determinants of STH infection among PSAC. The odds of STH infection were lowest among PSAC living in urban areas (AOR = 0.55, 95% CI: 0.39–0.79), among those from households with safe water source (AOR = 0.67, 95% CI: 0.47–0.0.93), and in those PSAC from households with shorter distance from water source (<30 minutes) (AOR = 0.51, 95% CI: 0.39–0.67). On the other hand, the odds of STH infection were highest among PSAC from households that had no functional hand washing facility (AOR = 1.36, 95% CI: 1.04–1.77), in those PSAC from households that had unclean latrine (AOR: 1.82, 95% CI: 1.19–2.78), and among those PSAC under caregivers who had lower mean score on KP of STH transmission (AOR = 1.85, 95% CI: 1.13–3.01) (Table 3). Details on univariable and multivariable analyses are presented in Table 3.

Table 3. Univariable and multivariable analyses of selected risk factors related to STH infection among PSAC, Gamo Gofa zone, Southern Ethiopia, January 2019.

Variables Category STH infection status Univariable analysis, COR (95% CI) Multivariable analysis, AOR (95% CI)
Yes (n = 402) No (n = 804)
Place of residence Urban 51 202 0.43 (0.31–0.61)** 0.55 (0.39–0.79)*
Rural 351 602 Reference Reference
Children’s sex Male 221 408 1.18 (0.93–1.51)** --
Female 181 396 Reference
Children’s age (years) ≤2 136 258 1.08 (0.84–1.39) --
3–5 266 546 Reference
Water source Safe 322 690 0.66 (0.48–0.91)** 0.67 (0.47–0.93)*
Unsafe 80 114 Reference Reference
Treat water No 317 602 1.21(0.91–1.61)** --
Yes 85 197 Reference
Distance from water source <30 minutes 149 421 0.54 (0.42–0.68)** 0.51 (0.39–0.67)*
≥30 minutes 253 383 Reference Reference
Latrine clean (n = 1157) No 60 73 1.77 (1.23–2.55)** 1.82 (1.19–2.78)*
Yes 325 699 Reference Reference
Having functional hand wash facility (n = 1157) No 212 370 1.33 (1.04–1.70)** 1.36(1.04–1.77) *
Yes 173 402 Reference Reference
KP score on STH prevention ≤5 385 751 1.60 (0.91–2.80)** --
>5 17 53 Reference
Knowledge score on STH transmission ≤5 378 712 2.04 (1.28–3.24)** 1.85(1.13–3.01) *
>5 24 92 Reference Reference
Child hand wash habit before meal No 118 205 1.21 (0.93–1.58)** --
Yes 284 599 Reference
Child hand wash habit after defecation No 208 373 1.24 (0.97–1.57)** --
Yes 194 431 Reference
Caregivers hand wash habit after cleaning child No 33 89 0.72 (0.47–1.09)** --
Yes 369 715 Reference
Hand wash after cleaning child No 33 89 0.72 (0.47–1.09)** --
Yes 369 715 Reference
Received deworming drugs in the last year No 118 213 1.15 (0.88–1.50) --
Yes 284 591 Reference
Washing fruit or vegetables habit before eating No 135 232 1.25 (0.96–1.61)** --
Yes 267 572 Reference
Child started education No 339 646 1.32 (0.95–1.81)** --
Yes 63 158 Reference
Adequate water No 108 240 0.86 (0.66–1.13) --
Yes 294 564 Reference
Treat water No 317 607 1.21 (0.91–1.61) --
Yes 85 197 Reference
Latrine available (n = 1157) No 17 32 1.06 (0.58–1.94) --
Yes 385 772 Reference
Faeces or any dirt observed on latrine surface No 270 566 0.85 (0.65–1.12)** 0.06 (0.98–1.86)
Yes 115 206 Reference Reference
Child soil eating habit No 278 541 1.09 (0.84–1.41) --
Yes 124 263 Reference
Child shoe wear habit No 184 354 1.07 (0.84–1.36) --
Yes 218 450 Reference
Place of child body wash Home 380 750 1.24 (0.75–2.07)
River 22 54 Reference
Caregiver’s awareness on STH No 48 83 1.18 (0.81–1.72) --
Yes 354 721 Reference
Educational status of caregivers Cannot read and write 172 373 0.45 (0.19–1.03) --
Can read and write 84 106 0.26 (0.11–0.61)
Elementary 100 210 0.43 (0.18–1.01)
Secondary 39 81 0.43 (0.17–1.05)
Diploma and above 7 34 Reference
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Note: Variable (s) entered on step 1 in multivariable model were place of residence, child sex, age of caregivers, water sources, treat water, distance from water sources, latrine clean (faeces or any dirt observed on latrine surface/floor), having functional hand washing facility around latrine, wash fruits or vegetables before eating, child started education, hand wash habit after cleaning child, child hand washing habit before meal, child hand wash habit after defecation, caregiver’s KP score on STH prevention, and knowledge score on STH transmission.

COR = Crude odd ratio

AOR = Adjusted odd ratio

**P ≤0.25 at univariable analysis

AOR = Adjusted odds ratio

“Reference” = comparison group

*Statistically significant at 5% level of significance in multivariable model

Discussion

This study established context-specific evidences on determinants of STH infections among PSAC in the former Gamo Gofa Zone, Southern Ethiopia, to improve control strategies of STH.

Our study identified that WASH and behavioral related factors are significantly associated with STH infections among PSAC. Consistent with this, literatures suggest that improvements of WASH infrastructures and appropriate health-seeking behavior are essential for achieving sustained control and elimination of STH and many other NTDs at large [22, 23].

This study found that the odds of STH infection among PSAC who were living in urban area were lowest compared to those PSAC who were living in rural areas. This result is consistent with the findings observed in other developing countries, where STH infections were common in rural areas than urban areas [24]; the possible reason for lower odds of infection in urban area might be associated with availability of better WASH infrastructures than rural areas.

Similarly, the odds of STH infection among PSAC from households that had safe water source were lowest compared to those PSAC from households which had unsafe water source. The finding from this study corroborates with the finding of a study observed in another part of Ethiopia [19], and in other counties, such as Bangladesh [25], South Africa [26], Argentina [27] and South west China [4]. For instance, the Bangladesh study reported that "use of tube well water was associated with a 48% reduction in STH infection."

In addition, the odds of STH infection among PSAC from households with less distance from water source (<30 minutes) were lowest compared to those children from households that needed to walk longer distance (≥30 minutes) to collect water. In line with the result of this study, a systematic review and meta-analysis stated that "access to piped water was associated with lower odds of A. lumbricoides and T. trichiura infection" [23]. This is justifiable because increased access to water source can improve utilization of water for better hygiene practices which would in turn help to halt the cycle of STH transmission.

On the other hand, the odds of STH infection among PSAC children from households that had no functional hand washing facility, and those from households that had no clean latrine were highest than those who had functional hand washing facility and clean latrine. These results agree with the findings of a systematic review and meta-analysis [23, 28], and a study conducted in Uganda [29]. This finding can be possibly explained by the fact that improved sanitation and hygiene is associated with reduced odds of STH infection [15, 22, 23, 27, 28].

Likewise, our study found that the odds of STH infection among PSAC who were under caregivers with lower knowledge score on STH transmission (≤5) were nearly higher by 2 fold than those children whose caregivers had higher mean KP score. This finding supports the result of other study conducted in another part of Ethiopia [30]. The possible reason for significant association of lower knowledge on STH transmission could be related to weak social behavioral change communication intervention.

While the WHO as well as Ethiopian Ministry of Health recommend preventive chemotherapy as public health interventions to control and eliminate STH [7, 11]; in this study we have been amazed by the statistically insignificant association of deworming treatment on STH infection. This might be due to inadequate deworming coverage of PSAC and problems related to proper timing of mass drug administration (MDA), frequency of treatment and low compliance of treatment. The WHO recommends yearly deworming in communities with infection rates of 20% to 50%; however, without appropriate environmental and behavioral interventions, this may lead to re-infection rapidly after treatment. Consistent with this, a study conducted in China revealed that "statistically insignificant effect of deworming treatment on STH infection" [4].

The main strength of this study is that it identified determinants of STH with a good sample size and powered to estimate difference between groups, and it showed context-specific shortcomings of preventive chemotherapy intervention; as it will not be effective without WASH and behavioral interventions. However, in this study, the following limitations should be acknowledged. First, due to the retrospective nature of the study, data are subject to recall bias. Second, the lower positive predictive values in low-intensity settings in the Kato–Katz diagnostic technique might lead to misclassification of participants [31, 32].

Conclusions

Given efforts required to sustain control and elimination of STH by 2030 in PSAC; this study demonstrated that the existing preventive chemotherapy should be substantially strengthened with WASH and behavioral interventions. Thus, an urgent call for action is demanding to integrate context-specific WASH interventions, particularly in rural areas. Barriers related to effective implementation of MDA for STH need to be explored in future studies.

Supporting information

S1 Questionnaire. Data collection tool for face-to-face interview.

(DOCX)

Click here for additional data file. (30.7KB, docx)
S1 Dataset. SPSS dataset.

(SAV)

Click here for additional data file. (207.7KB, sav)

Acknowledgments

Authors would like thank the study participants, data collectors, supervisors, zonal health office heads, district health office heads and NTDs focal points in all selected districts of the study area for their continued support during implementation of the study.

Data Availability

All relevant data are within the manuscript and its Supporting information files.

Funding Statement

This study is made possible by the generous support of the Collaborative Research and Training Center, Arba Minch University, Ethiopia.

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Decision Letter 0

Kebede Deribe

28 Jul 2020

PONE-D-20-19992

Determinants of soil-transmitted helminth infection among pre-school-age children in Gamo Gofa zone, Southern Ethiopia: a case-control study

PLOS ONE

Dear Dr. Asfaw,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Your manuscript has been revised by two reviewers and they have raised important points you have to respond to.

Please submit your revised manuscript by Sep 11 2020 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

  • A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

  • A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

  • An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

We look forward to receiving your revised manuscript.

Kind regards,

Kebede Deribe, BSc, MPH, PhD

Academic Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2. Please include additional information regarding the survey or questionnaire used in the study and ensure that you have provided sufficient details that others could replicate the analyses. For instance, if you developed a questionnaire as part of this study and it is not under a copyright more restrictive than CC-BY, please include a copy, in both the original language and English, as Supporting Information.

3. We note you have included a table to which you do not refer in the text of your manuscript. Please ensure that you refer to Table 4 in your text; if accepted, production will need this reference to link the reader to the Table.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: No

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Determinants of soil-transmitted helminth infection among pre-school-age children in Gamo Gofa zone, Southern Ethiopia: a case-control study

The authors present the findings on determinants of STH infection among PSAC in a study area in Southern Ethiopia. The study provides evidence on the association of STH and WASH factors among PSAC group of children. Therefore, this is a relevant study and of interest to STH control programs.

General comments:

The entire manuscript should be checked and proofread for grammatical and spelling corrections

Specific comments:

Abstract:

Include the cut-off for lower mean score for KP, line 47.

Introduction:

Generally well written.

Methods:

Avoid a one sentence paragraphs. Please provide more and explicit information on the study design. Lines 96-97.

The stated age group of 1-5 years is not the generally used PSAC age group, for comparability of the results, amend the analysis using the generally used PSAC age group.

State how STH infection was defined as an outcome variable, was it any STH positive result? Line 119.

How was the questionnaire administered? Paper or technology-based? State how the method used guaranteed data quality and integrity. Lines 124-126.

How were scores for KP created? Lines 145-146

Usually, multivariable logistic regression model is build following a univariable logistic regression and variable selection process. Was univariable logistic regression conducted? Perhaps a table summarizing this result is necessary. However, I have noted that a bivariate analysis was conducted using chi-square test, you don’t need to present its results. Just note that univariable logistic regression is different with chi-square test. Why was p<0.25 considered for the bivariable analysis?

State the ethical approval number if the study was reviewed and approved. State if assent was obtained from children. Why was written consent not obtained from the parents/household heads? Lines 152-155

Results:

Give a paragraph summarizing the infection prevalence by each individual species and any STTH among the participants.

Instead of running the logistic regression model on only any STH, considering doing this analysis on each STH species as well. This would inform on the WASH variation on individual species.

State in the methods how latrine cleanliness was defined, lines 176.

Tables 3 and 4: Instead of writing “1” write “reference”, since this refers to the reference category. Put table note explaining what “--” means. Separate the multivariable analysis on its own table. Delete chi-square test results and put the univariable logistic regression results instead. Give the definition of unsafe/safe water source. Where are the results of multivariable analysis in table 4?

Discussion:

Generally written well but should be improved after addressing the above concerns touching on methods and results.

Reviewer #2: Review Report for Determinants of soil-transmitted helminth infection among pre-school-age children in Gamo Gofa zone, Southern Ethiopia: a case-control study

Thank you for the opportunity to review this paper that explores the role of WASH in STH infection among pre-school-aged children. While the study provides new information, there is need for more detail on how the study was conducted. The tables also need to organized for provide sharper message. For example, table one wold look at child level factor based on information from primary care givers. Next can look at wash specific factors. The discussion should also be consolidated to comparison of the current study with other published studies

A few specific questions

1. Are there any contextual differences in the kebeles selected?

2. There is no justification provided why PSAC not SAC, the references provided in the first paragraph on the introduction need to be updated.

3. This statement is true for SAC not sure about PSAC

“It has been provided for all PSAC for many years in endemic 70 countries including Ethiopia in areas where the baseline prevalence of any soil-transmitted 71 infections is 20% or higher among children, in order to control and eliminate STH”

4. Description of Kato katz procedure is not described.

5. Ethics statement mentions oral consent, I appreciate different settings have varied ethical requirements, just wondering whether in this setting oral consent is sufficient

6. How was the sampling done

**********

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

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Submitted filename: Review comments.docx

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PLoS One. 2020 Dec 11;15(12):e0243836. doi: 10.1371/journal.pone.0243836.r002

Author response to Decision Letter 0

14 Sep 2020

Author Response

In general, authors highly valued the reviewers’ and editor’s comments. Accordingly, amendments have been made.

Response to editor’s comments

Journal Requirements:

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming.

Response: The manuscript has been modified to satisfy all the journal requirements.

2. Please include additional information regarding the survey or questionnaire used in the study and ensure that you have provided sufficient details that others could replicate the analyses.

Response: The survey questionnaire has been included as additional information in the revised version.

3. We note you have included a table to which you do not refer in the text of your manuscript. Please ensure that you refer to Table 4 in your text; if accepted, production will need this reference to link the reader to the Table.

Response: We appreciate the editor’s comments, and now correction has been made, line 220.

4. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Response: Authors would like to thank and acknowledge the editors’ concern. Accordingly, the manuscript has been amended to meet PLOS ONE’s publication criteria.

Response to Reviewers' comments

Reviewer #1

1. The entire manuscript should be checked and proofread for grammatical and spelling corrections.

Response: The manuscript has been proofread with editing made wherever necessary.

2. Abstract: Include the cut-off for lower mean score for KP, line 47

Response: Authors appreciate the reviewer’s concern. Agreed, correction has been made, line 48.

3. Methods: Avoid a one sentence paragraphs. Please provide more and explicit information on the study design. Lines 96-97

Response: Agreed, now amendments have been made in the revised version, lines 101-104.

4. Methods: The stated age group of 1-5 years is not the generally used PSAC age group, for comparability of the results, amend the analysis using the generally used PSAC age group.

Response: Authors appreciated for the reviewer’s concern. However, since there is no consistent definition of PSAC in the existing literatures, in this study, all children aged 1 to 5 years who are not yet attending (primary) school were considered as pre-school children (lines 108-110) , as supported by WHO (please see at: http://whqlibdoc.who.int/publications/2006/9241547103_eng.pdf) and other studies, such as https://doi.org/10.1186/s12879-018-3289-0 and https://doi.org/10.1186/s40249-019-0561-5. Moreover, in Ethiopia, almost all children start primary school after the age of 5.

5. Methods: State how STH infection was defined as an outcome variable, was it any STH positive result? Line 119

Response: Agreed. In our study, the STH infection status was defined as being positive or negative for any STH species. Lines 128-129

6. How was the questionnaire administered? Paper or technology-based?

Response: Paper based questionnaire was administered through face-to-face interviews.

7. State how the method used guaranteed data quality and integrity. Lines 124-126

Response: Authors appreciated the concern raised by reviewer; however, we think that the issues raised by the reviewer were addressed at quality control section of the manuscript (See at lines 159-163 in the revised version).

8. Methods: How were scores for KP created? Lines 145-146

Response: We appreciated for the question. We measured knowledge score on STH transmission using 11 questions, and score on knowledge and practice on STH prevention was computed using 12 questions by counting value within a case in SPSS version 25.0. Lines 171-173 in the revised version

9. Methods: Usually, multivariable logistic regression model is built following a univariable logistic regression and variable selection process. Was univariable logistic regression conducted? Perhaps a table summarizing this result is necessary. However, I have noted that a bivariate analysis was conducted using chi-square test; you don’t need to present its results. Just note that univariable logistic regression is different with chi-square test. Why was p<0.25 considered for the bivariable analysis?

Response: Authors are grateful for the reviewer’s comments. Note that data presented as ‘bivariate analysis’ should be considered as ‘univariable logistic regression’. Again, note that p < 0.25 was not used for the ‘bivariate analysis; we did it for ‘univariable logistic regression’ to enter candidate variables into ‘multivariable logistic regression’. The reason for using p < 0.25 was to improve the chances of remaining potential variables in the multivariable model. With consideration given to reviewer’s comments, now amendment has been made in the revised version. Lines 201-212

10. Methods: State the ethical approval number if the study was reviewed and approved. State if assent was obtained from children. Why was written consent not obtained from the parents/household heads? Lines 152-155

Response: Thank you for the comments. Now the ethical issue is addressed. The reference number was: CMHS/11222/111). Assent was not obtained from PSAC since we believe that caregivers are responsible on behalf of them, lines 183-185.

11. Results: Give a paragraph summarizing the infection prevalence by each individual species and any STTH among the participants.

Response: With regard to infection prevalence by each individual STH species, overall, ascariasis was the most prevalent (27.7%), followed by trichiurasis (11.9%) and hookworms (4.6%), and 8% PSAC were infected with two STH species (ascariasis and trichiurasis), lines 190-193.

12. Results: Instead of running the logistic regression model on only any STH, considering doing this analysis on each STH species as well. This would inform on the WASH variation on individual species.

Response: Authors appreciated for the reviewer’s comments; however, from the very beginning of the study, the sample size was calculated based on infection status of any STH species as (cases vs. controls) by taking our hypothesis - any STH infection have shared WASH factors into consideration.

13. Results: State in the methods how latrine cleanliness was defined, lines 176.

Response: Authors thanks for reviewer comments. The issue has been addressed. Lines 174-175

14. Results: Tables 3 and 4: Instead of writing “1” write “reference”, since this refers to the reference category. Put table note explaining what “--” means. Separate the multivariable analysis on its own table. Delete chi-square test results and put the univariable logistic regression results instead. Give the definition of unsafe/safe water source. Where are the results of multivariable analysis in table 4?

Response: Agreed. The issue has been addressed in the revised version. In the table 3 of the revised manuscript, the multi-variable analysis was done for variables with P<0.25 in univariable analysis. Please note that we used backward stepwise method to enter potential variables into the multi-variable analysis, which result in seven variables to be remained in the final model, as it is indicated with an AOR (95% CI) in the table 3. In addition, note that the multivariable model was placed at side of univariable analysis just for comparison purpose, if it does not make sense in this way it is possible to separate simply. Table 4 is edited as table 3. Lines 231-235

15. Discussion: Generally written well but should be improved after addressing the above concerns touching on methods and results.

Response: Thank you. Now some improvements have been made in the revised version.

Reviewer #2

1. While the study provides new information, there is need for more detail on how the study was conducted. The tables also need to organized for provide sharper message. For example, table one wold look at child level factor based on information from primary care givers. Next can look at wash specific factors. The discussion should also be consolidated to comparison of the current study with other published studies

Response: Agreed. Amendments have been made in the revised version.

2. Are there any contextual differences in the kebeles selected?

Response: We appreciated for the reviewer’s question. We assumed that there are socio-demographic and WASH related risk factors variations across the selected kebeles that that could contribute for difference in prevalence of STH.

3. There is no justification provided why PSAC not SAC, the references provided in the first paragraph on the introduction need to be updated.

Response: Authors valued the reviewer’s comment. Agreed., revision has been made as: Since there is no consistent definition of PSAC in the existing literatures, in this study, all children aged 1 to 5 years who are not yet attending (primary) were considered as pre-school children (lines 108-110) , as supported by WHO guideline (see at: http://whqlibdoc.who.int/publications/2006/9241547103_eng.pdf.

In fact, in Ethiopia, almost all children start primary school after the age of 5. In addition, for comparison purpose, other studies, which were conducted in South Africa and Uganda also considered PSAC as children aged 1 to 5.

4. This statement is true for SAC not sure about PSAC

“It has been provided for all PSAC for many years in endemic 70 countries including Ethiopia in areas where the baseline prevalence of any soil-transmitted 71 infections is 20% or higher among children, in order to control and eliminate STH”

Response: We think as it may works for PSAC. But we found the statement -“between 2001 and 2009, the number of school-age children benefiting from deworming programmes had tripled to more than 200 million in over 60 countries.” (Weekly Epidemiological Record, 2011, 25(86):257–268).

5. Description of Kato katz procedure is not described.

Response: Now the Kato katz procedure has been described in the revised version, lines 144-157.

6. Ethics statement mentions oral consent, I appreciate different settings have varied ethical requirements, just wondering whether in this setting oral consent is sufficient

Response: Oral and written consent was received from district administrators and heads of the households before the data collection began. Lines 183-184

7. How was the sampling done?

Response: We thank for the important question. The sampling was done by taking probability proportionate to sample size into account based on the number of cases in the cross-sectional study; which was conducted ahead of this study in the same study area, lines 122-126

Attachment

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Decision Letter 1

Kebede Deribe

21 Oct 2020

PONE-D-20-19992R1

Determinants of soil-transmitted helminth infections among pre-school-age children in Gamo Gofa zone, Southern Ethiopia: a case-control study

PLOS ONE

Dear Dr. Asfaw,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by Dec 05 2020 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

  • A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

  • A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

  • An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

We look forward to receiving your revised manuscript.

Kind regards,

Kebede Deribe, BSc, MPH, PhD

Academic Editor

PLOS ONE

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: (No Response)

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: The authors have done a great job to address explicitly all my earlier comments. However, as I had stated earlier, some grammatical and sentence construction errors remain that need to be addressed. Perhaps, an independent copy editing need to be considered. Additionally, the authors need to make it clear whether they used P<0.25 (line 202) or P≤0.25 (line 209) for univariable analysis, make this consistent throughout the text. In table 3, indicate the word “Reference” on the comparison categories.

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

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PLoS One. 2020 Dec 11;15(12):e0243836. doi: 10.1371/journal.pone.0243836.r004

Author response to Decision Letter 1

2 Nov 2020

Authors’ Responses

Authors highly valued and appreciate the editor’s and reviewers’ comments. The manuscript has been modified accordingly.

Response to Reviewer’s comments

Reviewer #1

1. The authors have done a great job to address explicitly all my earlier comments. However, as I had stated earlier, some grammatical and sentence construction errors remain that need to be addressed. Perhaps, an independent copy editing need to be considered.

Response: Authors are grateful for the reviewer’s comments. With special attention given to grammatical and sentence construction errors, the entire manuscript has been checked and proofread for grammatical and spelling corrections.

2. Additionally, the authors need to make it clear whether they used P<0.25 (line 202) or P≤0.25 (line 209) for univariable analysis, make this consistent throughout the text.

Response: Agreed, thank you. Correction has been made. And please note that we used at P ≤0.25 to select potential variables for fitting into multi-varable model. We made correction on the revised version of the manuscript accordingly.

3. In Table 3, indicate the word “Reference” on the comparison categories.

Response: Agreed, correction has been made in the revised version.

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Decision Letter 2

Kebede Deribe

6 Nov 2020

PONE-D-20-19992R2

Determinants of soil-transmitted helminth infections among pre-school-aged children in Gamo Gofa zone, Southern Ethiopia: a case-control study

PLOS ONE

Dear Dr. Asfaw,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

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We look forward to receiving your revised manuscript.

Kind regards,

Kebede Deribe, BSc, MPH, PhD

Academic Editor

PLOS ONE

Additional Editor Comments (if provided):

Table 3: Faeces or any dirt observed on latrine surface, in the Multi-variable analysis, AOR (95%CI) column provide the reference category.

Table 3. Educational status of caregivers, provide the Univariable analysis, COR (95%CI) for the categories

• Can read and write

• Elementary

• Secondary

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PLoS One. 2020 Dec 11;15(12):e0243836. doi: 10.1371/journal.pone.0243836.r006

Author response to Decision Letter 2

9 Nov 2020

Authors’ Responses

Authors are grateful for the editor’s comments, and the manuscript has been amended accordingly.

Response to editors’ comments

1. Table 3: Faeces or any dirt observed on latrine surface, in the Multi-variable analysis, AOR (95%CI) column provide the reference category.

Response: Agreed, correction has been made in the table at line 235.

2. Table 3. Educational status of caregivers, provide the Univariable analysis, COR (95%CI) for the categories

• Can read and write

• Elementary

• Secondary

Response: Agreed, correction has been made in the table at line 235.

Attachment

Submitted filename: Response to Reviewers.docx

Click here for additional data file. (24KB, docx)

Decision Letter 3

Kebede Deribe

27 Nov 2020

Determinants of soil-transmitted helminth infections among pre-school-aged children in Gamo Gofa zone, Southern Ethiopia: a case-control study

PONE-D-20-19992R3

Dear Dr. Asfaw,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

Kebede Deribe, BSc, MPH, PhD

Academic Editor

PLOS ONE

Acceptance letter

Kebede Deribe

2 Dec 2020

PONE-D-20-19992R3

Determinants of soil-transmitted helminth infections among pre-school-aged children in Gamo Gofa zone, Southern Ethiopia: a case-control study

Dear Dr. Asfaw:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

If we can help with anything else, please email us at plosone@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Dr. Kebede Deribe

Academic Editor

PLOS ONE

Associated Data

    This section collects any data citations, data availability statements, or supplementary materials included in this article.

    Supplementary Materials

    S1 Questionnaire. Data collection tool for face-to-face interview.

    (DOCX)

    Click here for additional data file. (30.7KB, docx)
    S1 Dataset. SPSS dataset.

    (SAV)

    Click here for additional data file. (207.7KB, sav)
    Attachment

    Submitted filename: Review comments.docx

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    Attachment

    Submitted filename: Response to Reviewers.docx

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    Attachment

    Submitted filename: Review comments R1.docx

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    Attachment

    Submitted filename: Response to Reviewers.docx

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    Attachment

    Submitted filename: Response to Reviewers.docx

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    Data Availability Statement

    All relevant data are within the manuscript and its Supporting information files.

    Articles from PLoS ONE are provided here courtesy of PLOS

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