Performance evaluation of Baermann techniques: The quest for developing a microscopy reference standard for the diagnosis of Strongyloides stercoralis

BackgroundSoil-transmitted helminths (STH) are common in low and middle income countries where there is lack of access to clean water and sanitation. Effective diagnosis and treatment are essential for the control of STH infections. However, among STH parasites, Strongyloides stercoralis is the most neglected species, both in diagnostics and control strategies. Diagnostic methods cover different approaches, each with different sensitivities and specificities, such as serology, molecular techniques and microscopy based techniques. Of the later, the Baermann technique is the most commonly used procedure. In the literature, several ways have been described to perform the Baermann method, which illustrates the overall lack of a ‘(gold) reference standard’ method for the diagnosis of S. stercoralis infection. In this study we have evaluated the performance of three Baermann techniques in order to improve the reference standard for the microscopic diagnosis of S. stercoralis infection thereby facilitating individual case detection, mapping of the disease and proper evaluation of treatment responses.Methods/Principal findingsA community based cross sectional study was conducted at Zenzelima, Bahir Dar Zuria Ethiopia. A total of 437 stool samples were collected and analyzed by the following procedures: conventional Baermann (CB), modified Baermann (MB), and modified Baermann with charcoal pre-incubation (MBCI). The diagnostic sensitivity and Negative Predictive Value (NPV) of each technique was calculated using the combination of all the three techniques as a composite reference standard. Our result indicated that larvae of S. stercoralis were detected in 151 (34.6%) stool samples. The prevalence of S. stercoralis infection based on the three diagnostic methods was 9.6%, 8.0%, and 31.3% by CB, MB, and MBCI respectively. The sensitivity and NPV for CB, MB, and MBCI were 26.7% and 70.8%, 22.1% and 69.6%, and 87.0% and 93.2%, respectively. The MBCI showed significant difference (P- value = <0.001) in the sensitivity and NPV values when compared with CB and MB values. The agreement between CB, MB, and MBCI with the composite reference standard was 31.8%, 26.7%, 89.6%, respectively.Conclusion/SignificanceOur results suggest the superior performance of MBCI. It is relatively easy to implement, simple to perform and comparatively cheaper. The CB is by far the commonly used method in routine diagnostic although this technique significantly underestimates the true burden of the disease and thereby contributing to the exclusion of S. stercoralis from the control strategies. Therefore, MBCI is recommended as a routine microscopy-based diagnostic test for S. stercoralis infection, particularly in settings where molecular procedures are not available.     

Exclusive breastfeeding status of children aged between 6 and 24 months in the nomadic population of Hadaleala district,Afar Region,northeast Ethiopia

Background

Exclusive breastfeeding (EBF) during infancy is fundamental, however it is not fully practiced in the nomadic population of Ethiopia. In Ethiopia, there is still a lack of information on the implementation of the EBF, especially among the nomadic population. This study was conducted to assess the EBF status of children during their first 6 months of life, who are now aged between 6 and 24 months, in the nomadic population of Afar region. The study also aimed to identify factors affecting exclusive breastfeeding.

Methods

A community based cross-sectional study was conducted from April to May, 2015 to assess EBF of children aged between 6 and 24 months during the first 6 months of life. Exclusive breastfeeding is defined as consuming only breast milk (including expressed breast milk) during the first 6 months and no other liquids and solid foods except medications, and non exclusive breastfeeding is taking liquids and solid foods in addition to breast milk. The cluster sampling technique was used to select the study participants. Data were collected from 254 households using a structured questionnaire.

Results

One hundred eighty eight of the children were fed breast milk exclusively for the first 6 months of age; the rate of EBF in the study area was 74% (95% CI 70, 78%). One hundred fifty four (60.6%) of the children received breast milk within 1 h immediately after birth and 207 (81.5%) of the children maintained breastfeeding at the time of the survey. Exclusive breastfeeding was statistically associated with mothers aged above 35 years (AOR 8.3, 95% CI 1.7, 40.3), commencing to breastfeed in first hour (AOR 3.5, 95% CI 1.8, 6.9), and parents who didn’t migrate or move to a more comfortable area (AOR 4.6, 95% CI 1.5, 14.4).

Conclusion

Exclusive breastfeeding was not fully practiced in the study area. Therefore, promotion of infant and young children feeding (IYCF) is needed in the area to strengthen EBF practices. Moreover, child feeding practices should be integrated with the existing health system and attention should be given to the nomadic mothers.