Sensitivity and specificity analysis for targeted selective treatment using eye colour chart in sheep flocks naturally infected with Haemonchus contortus
An eye color chart for screening the flock for anaemic sheep was developed and is in use since 2008 in organized farms in arid Rajasthan. In present analysis its accuracy (sensitivity and specificity) was analyzed in identifying anaemic sheep (PCV <18 or <22) and to quantify the proportion of...
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| Format: | Article |
| Language: | English |
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Indian Council of Agricultural Research
2014-11-01
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| Series: | Indian Journal of Animal Sciences |
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| Online Access: | https://epubs.icar.org.in/index.php/IJAnS/article/view/44719 |
| _version_ | 1797659569564942336 |
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| author | C P SWARNKAR D SINGH |
| author_facet | C P SWARNKAR D SINGH |
| author_sort | C P SWARNKAR |
| collection | DOAJ |
| description |
An eye color chart for screening the flock for anaemic sheep was developed and is in use since 2008 in organized farms in arid Rajasthan. In present analysis its accuracy (sensitivity and specificity) was analyzed in identifying anaemic sheep (PCV <18 or <22) and to quantify the proportion of sheep left untreated when using it for management of Haemonchus contortus. A linear trend was observed in proportion of true positives and level of FECs in all the seasons at both the PCV cut-off values. The percentage of correct treatment was maximum (71.3 to 83.4%) with moderate kappa index in individuals with intensity of infection >3001 epg. An inverse relation exists between sensitivity and specificity of the TST system. Based on criteria, the overall sensitivity of TST system ranged from 22.9% (criteria as FEC <1000 epg and PCV <18) to 90.1% (criteria as FEC >3001 epg and PCV <22). In visually anaemic animals, the sensitivity was lower when PCV cut-off <18% was considered positive test results. In highly infected animals, the sensitivity of TST system remained >85% during both monsoon season and winter. The overall specificity varied from 20.0 (criteria as FEC >3001 epg and PCV <22) to 81.5% (criteria as FEC <1,000 epg and PCV <18). Thus it appears that in sheep flocks predominantly infected with H. contortus, the application of the TST system as a guidance for the administration of anthelmintic drugs can be an important tool in management of GINs in Rajasthan.
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| issn | 0367-8318 2394-3327 |
| language | English |
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| series | Indian Journal of Animal Sciences |
| spelling | doaj.art-4909887ce775427bb76c3d5782d1a5a82023-10-16T05:57:13ZengIndian Council of Agricultural ResearchIndian Journal of Animal Sciences0367-83182394-33272014-11-01841110.56093/ijans.v84i11.44719Sensitivity and specificity analysis for targeted selective treatment using eye colour chart in sheep flocks naturally infected with Haemonchus contortusC P SWARNKAR0D SINGH1Central Sheep and Wool Research Institute, Avikanagar, Rajasthan 304 501 IndiaCentral Sheep and Wool Research Institute, Avikanagar, Rajasthan 304 501 India An eye color chart for screening the flock for anaemic sheep was developed and is in use since 2008 in organized farms in arid Rajasthan. In present analysis its accuracy (sensitivity and specificity) was analyzed in identifying anaemic sheep (PCV <18 or <22) and to quantify the proportion of sheep left untreated when using it for management of Haemonchus contortus. A linear trend was observed in proportion of true positives and level of FECs in all the seasons at both the PCV cut-off values. The percentage of correct treatment was maximum (71.3 to 83.4%) with moderate kappa index in individuals with intensity of infection >3001 epg. An inverse relation exists between sensitivity and specificity of the TST system. Based on criteria, the overall sensitivity of TST system ranged from 22.9% (criteria as FEC <1000 epg and PCV <18) to 90.1% (criteria as FEC >3001 epg and PCV <22). In visually anaemic animals, the sensitivity was lower when PCV cut-off <18% was considered positive test results. In highly infected animals, the sensitivity of TST system remained >85% during both monsoon season and winter. The overall specificity varied from 20.0 (criteria as FEC >3001 epg and PCV <22) to 81.5% (criteria as FEC <1,000 epg and PCV <18). Thus it appears that in sheep flocks predominantly infected with H. contortus, the application of the TST system as a guidance for the administration of anthelmintic drugs can be an important tool in management of GINs in Rajasthan. https://epubs.icar.org.in/index.php/IJAnS/article/view/44719AnaemiaEye colour chartHaemonchus contortusSensitivitySheepSpecificity |
| spellingShingle | C P SWARNKAR D SINGH Sensitivity and specificity analysis for targeted selective treatment using eye colour chart in sheep flocks naturally infected with Haemonchus contortus Indian Journal of Animal Sciences Anaemia Eye colour chart Haemonchus contortus Sensitivity Sheep Specificity |
| title | Sensitivity and specificity analysis for targeted selective treatment using eye colour chart in sheep flocks naturally infected with Haemonchus contortus |
| title_full | Sensitivity and specificity analysis for targeted selective treatment using eye colour chart in sheep flocks naturally infected with Haemonchus contortus |
| title_fullStr | Sensitivity and specificity analysis for targeted selective treatment using eye colour chart in sheep flocks naturally infected with Haemonchus contortus |
| title_full_unstemmed | Sensitivity and specificity analysis for targeted selective treatment using eye colour chart in sheep flocks naturally infected with Haemonchus contortus |
| title_short | Sensitivity and specificity analysis for targeted selective treatment using eye colour chart in sheep flocks naturally infected with Haemonchus contortus |
| title_sort | sensitivity and specificity analysis for targeted selective treatment using eye colour chart in sheep flocks naturally infected with haemonchus contortus |
| topic | Anaemia Eye colour chart Haemonchus contortus Sensitivity Sheep Specificity |
| url | https://epubs.icar.org.in/index.php/IJAnS/article/view/44719 |
| work_keys_str_mv | AT cpswarnkar sensitivityandspecificityanalysisfortargetedselectivetreatmentusingeyecolourchartinsheepflocksnaturallyinfectedwithhaemonchuscontortus AT dsingh sensitivityandspecificityanalysisfortargetedselectivetreatmentusingeyecolourchartinsheepflocksnaturallyinfectedwithhaemonchuscontortus |