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BACKGROUND: The point-of-care circulating cathodic antigen (POC-CCA) test is increasingly used as a rapid diagnostic method for Schistosoma mansoni infection. The test has good sensitivity, although false positive results have been reported among pregnant women and patients with urine infections and hematuria. We validated the POC-CCA test's ability to diagnose Schistosoma mekongi infection in Lao People's Democratic Republic (Lao PDR), where S. mekongi is endemic. Of particular interest was the test's specificity and possible cross-reactivity with other helminth infections. METHODS: We conducted a cross-sectional study of children and adults in the provinces of Champasack (Schistosoma mekongi and Opisthorchis viverrini endemic), Savannakhet (O. viverrini endemic) and Luang Prabang (soil-transmitted helminths endemic) between October 2018 and April 2019. POC-CCA and urine dipstick tests were administered to all study participants, while an additional pregnancy test was offered to women. Two stool samples were collected from participants and examined with a Kato-Katz test (two smears per stool). Logistic regression was used to associate potential confounding factors (predictors) with POC-CCA test results (outcome). RESULTS: In S. mekongi-endemic Champasack, 11.5% (n = 366) and 0.5% (n = 2) of study participants had positive POC-CCA and Kato-Katz test results, respectively. Only one of the two Kato-Katz positive patients was also POC-CCA positive. In Champasack and Luang Prabang, where S. mekongi is not endemic, the POC-CCA test yielded (presumably) false positive results for 6.0% (n = 22) and 2.5% (n = 9) of study participants, respectively, while all of the Kato-Katz tests were negative. POC-CCA positive test results were significantly associated with O. viverrini infection (1.69, 95% confidence interval (CI): 1.02–2.77, P = 0.042), increased leukocytes (adjusted Odds Ratio (aOR) = 1.58, 95% CI: 1.15–2.17, P = 0.005) and hematuria (aOR = 1.50, 95% CI: 1.07–2.10, P = 0.019) if the observed trace was counted as a ...

In Southeast Asia, the large majority of the population remains affected by parasitic worms despite longstanding mass treatment and health education campaigns. Soil-transmitted helminths and also the fish-borne liver fluke negatively affect development during early childhood. Here, the prevalence of helminth infections in stool samples of 610 mother-child pairs from Khammouane, Bolikhamxay and Vientiane provinces in Lao People's Democratic Republic was determined by formalin-ethyl acetate concentration technique. Overall, 15.1% of the children and 46.9% of the mothers were positive for at least one helminth species. Helminth detection rates varied significantly by province with the highest prevelance in Khammouane and the lowest in Bolikhamxay province. Mothers that were positive for soil-transmitted helminths were significantly more likely to have children positive for the same helminth species (p < 0.01) but this was not the case for the liver fluke Opisthorchis viverrini. A protective effect of breastfeeding against soil-transmitted helminths was revealed. Our data reconfirm the generally high helminth burden among mother-child pairs who likely share a number of risky lifestyle behaviors also with other family members. To reduce maternal burden of helminths, we propose that anti-helmintic treatment of women of childbearing age and of mothers during postnatal care should be included in the national strategy.

Objectives: Breastfeeding rates are decreasing rapidly in many low and middle-income countries, disproportionately affecting urban residences. We use data from Lao People's Democratic Republic to identify primary mechanisms underlying the urban-rural gap in breastfeeding practices. Methods: We used data from the 2017 Lao Social Indicator Survey II. Residence was categorized as large-urban (>1 million), small-urban (<1 Million), and rural. Multivariable logistic regression provided odds ratios and 95% confidence intervals (CI) to identify factors attributing to the urban-rural differences in complying with World Health Organization's breastfeeding recommendations for children <24 months. Results: Mothers in large-urban residences had 3.78 (95% confidence intervals: 1.19, 11.95) and 4.67 (95% CI: 2.30, 9.46) higher odds of non-compliance with exclusive and complementary breastfeeding recommendations, respectively, than mothers living in rural areas in bivariate models. Breastfeeding differentials between small urban and rural residences were largely explained by differences in maternal education and household wealth. Conclusion: Results of our paper suggest large disparities in breastfeeding practices between large-urban, small-urban, and rural residences.

Strongyloides stercoralis is present worldwide, but its prevalence is still uncertain, mainly due to the lack of sensitivity of diagnostic methods. Molecular techniques are under development, but a standardized protocol is still unavailable. We compared the sensitivity of real-time PCR, using two extraction protocols, with that of the Baermann technique. Samples were collected in the framework of the baseline screening of a randomized clinical trial evaluating moxidectin against S. stercoralis in Lao People's Democratic Republic. Two stool samples from each participant were processed by the Baermann method, and one subsample was processed by PCR. DNA was extracted using the QIAamp DNA stool minikit based on the standard protocol for the QIAamp DNA minikit (QIA) and using a modification of the QIA procedure (POL). Subsequently, all extracted samples were analyzed by real-time PCR. Overall, 95 samples were analyzed by the three diagnostic methods. Sixty-nine (72.6%) samples were positive according to the Baermann method, 25 (26.3%) by the QIA method, and 62 (65.3%) by the POL method. The sensitivities were 86% (95% confidence interval [CI], 76.7 to 92.9), 31.0% (95% CI, 21.3 to 42.6), and 78.0% (95% CI, 66.8 to 86.1) for the Baermann, QIA, and POL methods, respectively. The sensitivities calculated for each day of the Baermann method separately were 60% (48.4 to 70.8%) and 64% (52.2 to 74.2%) for days 1 and 2, respectively. In conclusion, the POL method revealed a good performance and was comparable to the Baermann test performed on two stool samples and superior to the Baermann method performed on one stool sample. Additional studies are needed to standardize a PCR protocol for S. stercoralis diagnosis.

Opisthorchiasis is a neglected tropical disease, yet it is of considerable public health importance in Southeast Asia given the predilection for chronically infected persons to develop cholangiocarcinoma. We evaluated a handheld microscope for the diagnosis of Opisthorchis viverrini in a community-based setting in Lao People's Democratic Republic in comparison with conventional light microscopy. In stool samples collected from 104 individuals, handheld microscopy revealed a sensitivity of 70.6% and a specificity of 89.5% for O. viverrini infection. Pearson's correlation for quantitative fecal egg counts between the two devices was 0.98 (95% confidence interval: 0.98–0.99). With small adjustments to further increase diagnostic sensitivity, a handheld microscope may become a helpful tool to screen for O. viverrini and other helminth infections in public health settings.

The areas endemic for schistosomiasis in the Lao People's Democratic Republic and in Cambodia were first reported 50 and 60 years ago, respectively. However, the causative parasite Schistosoma mekongi was not recognized as a separate species until 1978. The infection is distributed along a limited part of the Mekong River, regulated by the focal distribution of the intermediate snail host Neotricula aperta. Although more sensitive diagnostics imply a higher figure, the current use of stool examinations suggests that only about 1500 people are presently infected. This well-characterized setting should offer an exemplary potential for the elimination of the disease from its endemic areas; yet, the local topography, reservoir animals, and a dearth of safe water sources make transmission control a challenge. Control activities based on mass drug administration resulted in strong advances, and prevalence was reduced to less than 5% according to stool microscopy. Even so, transmission continues unabated, and the true number of infected people could be as much as 10 times higher than reported. On-going control activities are discussed together with plans for the future.