Trachoma survey methods: a literature review
Reliable population-based prevalence data are essential for planning, monitoring and evaluating trachoma control programmes and understanding the scale of the problem, yet they are not currently available for 22 out of 56 trachoma-endemic countries. Three survey methods have been advocated for trach...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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The World Health Organization
2009-02-01
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| Series: | Bulletin of the World Health Organization |
| Online Access: | http://www.scielosp.org/scielo.php?script=sci_arttext&pid=S0042-96862009000200017&lng=en&tlng=en |
| _version_ | 1797288492733038592 |
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| author | Jeremiah Ngondi Mark Reacher Fiona Matthews Carol Brayne Paul Emerson |
| author_facet | Jeremiah Ngondi Mark Reacher Fiona Matthews Carol Brayne Paul Emerson |
| author_sort | Jeremiah Ngondi |
| collection | DOAJ |
| description | Reliable population-based prevalence data are essential for planning, monitoring and evaluating trachoma control programmes and understanding the scale of the problem, yet they are not currently available for 22 out of 56 trachoma-endemic countries. Three survey methods have been advocated for trachoma: cluster random sampling (CRS); trachoma rapid assessment (TRA); and acceptance sampling trachoma rapid assessment (ASTRA). Our review highlights the benefits of CRS being simple, efficient, repeatable and giving population-based prevalence estimates of all signs of trachoma. There are limitations to TRA, which include: non-representative sampling; does not estimate prevalence; and lacks consistency and accuracy. ASTRA advocates small sample sizes but it is relatively complex, may result in imprecise prevalence estimates and does not estimate cicatricial signs of trachoma. We conclude that CRS should therefore remain the "gold" standard for trachoma surveys. However, among the CRS surveys reviewed, we also found several methodological deficiencies of sample-size calculations, standardization of trachoma graders, reporting of confidence intervals of prevalence estimates, variability of age groups for presentation of age-specific prevalence, and lack of estimation of district prevalence estimates. Properly conducted surveys will be crucial if the objective of global elimination of blinding trachoma is to be charted and realized. Harmonization of survey methods will enhance the conduct and comparability of trachoma surveys needed for reliable mapping of prevalence within endemic countries. Consistent with WHO recommendations, we advocate for continued use of CRS as the survey design of choice for trachoma control programmes and propose ways of improving future surveys based on this method. |
| first_indexed | 2024-03-07T18:50:16Z |
| format | Article |
| id | doaj.art-46c3832a86564496a4407f7ee7e696ff |
| institution | Directory Open Access Journal |
| issn | 0042-9686 |
| language | English |
| last_indexed | 2024-03-07T18:50:16Z |
| publishDate | 2009-02-01 |
| publisher | The World Health Organization |
| record_format | Article |
| series | Bulletin of the World Health Organization |
| spelling | doaj.art-46c3832a86564496a4407f7ee7e696ff2024-03-02T01:48:54ZengThe World Health OrganizationBulletin of the World Health Organization0042-96862009-02-01872143151S0042-96862009000200017Trachoma survey methods: a literature reviewJeremiah Ngondi0Mark Reacher1Fiona Matthews2Carol Brayne3Paul Emerson4University of CambridgeHealth Protection AgencyInstitute of Public HealthUniversity of CambridgeThe Carter CenterReliable population-based prevalence data are essential for planning, monitoring and evaluating trachoma control programmes and understanding the scale of the problem, yet they are not currently available for 22 out of 56 trachoma-endemic countries. Three survey methods have been advocated for trachoma: cluster random sampling (CRS); trachoma rapid assessment (TRA); and acceptance sampling trachoma rapid assessment (ASTRA). Our review highlights the benefits of CRS being simple, efficient, repeatable and giving population-based prevalence estimates of all signs of trachoma. There are limitations to TRA, which include: non-representative sampling; does not estimate prevalence; and lacks consistency and accuracy. ASTRA advocates small sample sizes but it is relatively complex, may result in imprecise prevalence estimates and does not estimate cicatricial signs of trachoma. We conclude that CRS should therefore remain the "gold" standard for trachoma surveys. However, among the CRS surveys reviewed, we also found several methodological deficiencies of sample-size calculations, standardization of trachoma graders, reporting of confidence intervals of prevalence estimates, variability of age groups for presentation of age-specific prevalence, and lack of estimation of district prevalence estimates. Properly conducted surveys will be crucial if the objective of global elimination of blinding trachoma is to be charted and realized. Harmonization of survey methods will enhance the conduct and comparability of trachoma surveys needed for reliable mapping of prevalence within endemic countries. Consistent with WHO recommendations, we advocate for continued use of CRS as the survey design of choice for trachoma control programmes and propose ways of improving future surveys based on this method.http://www.scielosp.org/scielo.php?script=sci_arttext&pid=S0042-96862009000200017&lng=en&tlng=en |
| spellingShingle | Jeremiah Ngondi Mark Reacher Fiona Matthews Carol Brayne Paul Emerson Trachoma survey methods: a literature review Bulletin of the World Health Organization |
| title | Trachoma survey methods: a literature review |
| title_full | Trachoma survey methods: a literature review |
| title_fullStr | Trachoma survey methods: a literature review |
| title_full_unstemmed | Trachoma survey methods: a literature review |
| title_short | Trachoma survey methods: a literature review |
| title_sort | trachoma survey methods a literature review |
| url | http://www.scielosp.org/scielo.php?script=sci_arttext&pid=S0042-96862009000200017&lng=en&tlng=en |
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