Soil-transmitted helminth infections are common throughout the tropics and subtropics and they disproportionately affect the poorest of the poor. In view of a growing global commitment to control soil-transmitted helminthiasis, there is a need to elucidate the effect of repeated stool sampling and the use of different diagnostic methods in areas targeted for preventive chemotherapy that are characterized by low-infection intensities. In this study, we focused on schoolchildren on Unguja Island, Zanzibar, an area where anthelminthic drugs have been repeatedly administered over the past decade. Three serial stool samples from each of 342 schoolchildren were examined using the Kato-Katz (K-K), Koga agar plate (KAP), and Baermann (BM) techniques. These methods were used individually or in combination for the diagnosis of Ascaris lumbricoides (K-K), Trichuris trichiura (K-K), hookworm (K-K and KAP), and Strongyloides stercoralis (KAP and BM). The examination of multiple stool samples instead of a single one resulted in an increase of the observed prevalence; e.g., an increase of 161% for hookworm using the K-K method. The diagnostic sensitivity of single stool sampling ranged between 20.7% for BM to detect S. stercoralis and 84.2% for K-K to diagnose A. lumbricoides. Highest sensitivities were observed when different diagnostic approaches were combined. The observed prevalences for T. trichiura, hookworm, A. lumbricoides, and S. stercoralis were 47.9%, 22.5%, 16.5%, and 10.8% after examining 3 stool samples. These values are close to the ‘true’ prevalences predicted by a mathematical model. Rigorous epidemiologic surveillance of soil-transmitted helminthiasis in the era of preventive chemotherapy is facilitated by multiple stool sampling bolstered by different diagnostic techniques. Diseases caused by parasitic worms inflict an enormous public health burden in developing countries. There is a growing effort to control worms with drugs. The success of repeated drug administrations can be assessed by measuring the decline in the prevalence and intensity of worm infections. Accurate diagnosis is a challenge, especially in areas with low infection intensities. We studied the effect of stool sampling efforts and the use of different diagnostic techniques on the measured prevalence of worms, including hookworm, large intestinal roundworm (Ascaris lumbricoides), whipworm (Trichuris trichiura), and dwarf threadworm (Strongyloides stercoralis) in Zanzibar, where worm control has been implemented over the past decade. Three early morning stool samples were collected from each of 342 schoolchildren on 3 consecutive days and analyzed with different techniques. The observed prevalence of the different worms increased with an enhanced sampling effort and when different diagnostic methods were combined. Examination of 3 stool samples per individual resulted in prevalences of T. trichiura, hookworm, A. lumbricoides, and S. stercoralis of 47.9%, 22.5%, 16.5%, and 10.8%, respectively. To conclude, the examination of multiple stool samples and the use of different techniques are recommended for accurate diagnosis of worms in areas undergoing repeated mass drug administration.

Infections with schistosomes and soil-transmitted helminths exert a considerable yet underappreciated economic and public health burden on afflicted populations. Accurate diagnosis is crucial for patient management, drug efficacy evaluations, and monitoring of large-scale community-based control programs. The diagnostic accuracy of four copromicroscopic techniques (i.e., Kato-Katz, Koga agar plate, ether-concentration, and FLOTAC) for the detection of Schistosoma mansoni and soil-transmitted helminth eggs was compared using stool samples from 112 school children in Côte d'Ivoire. Combined results of all four methods served as a diagnostic ‘gold’ standard and revealed prevalences of S. mansoni, hookworm, Trichuris trichiura, Strongyloides stercoralis and Ascaris lumbricoides of 83.0%, 55.4%, 40.2%, 33.9% and 28.6%, respectively. A single FLOTAC from stool samples preserved in sodium acetate-acetic acid-formalin for 30 or 83 days showed a higher sensitivity for S. mansoni diagnosis (91.4%) than the ether-concentration method on stool samples preserved for 40 days (85.0%) or triplicate Kato-Katz using fresh stool samples (77.4%). Moreover, a single FLOTAC detected hookworm, A. lumbricoides and T. trichiura infections with a higher sensitivity than any of the other methods used, but resulted in lower egg counts. The Koga agar plate method was the most accurate diagnostic assay for S. stercoralis. We have shown that the FLOTAC method holds promise for the diagnosis of S. mansoni. Moreover, our study confirms that FLOTAC is a sensitive technique for detection of common soil-transmitted helminths. For the diagnosis of S. stercoralis, the Koga agar plate method remains the method of choice. Infections with parasitic worms (e.g., Schistosoma mansoni, hookworm, roundworm, whipworm, and threadworm) are still widespread in the developing world. Accurate diagnosis is important for better patient management and for monitoring of deworming programs. Unfortunately, methods to detect parasite eggs or larvae in stool samples lack sensitivity, particularly when infection intensities are low. The most widely used method for the diagnosis of S. mansoni, hookworm, roundworm and whipworm in epidemiological surveys is the Kato-Katz technique. Recently, the FLOTAC technique has shown a higher sensitivity than the Kato-Katz method for the diagnosis of hookworm, roundworm and whipworm, but no data are available for S. mansoni. We compared the diagnostic accuracy of the FLOTAC with the Kato-Katz, ether-concentration and Koga agar plate techniques for S. mansoni and other parasitic worm infections using stool samples from 112 school children from Côte d'Ivoire. FLOTAC showed the highest sensitivity for S. mansoni diagnosis. Egg counts, however, were lower when using FLOTAC, an issue which needs further investigations. The FLOTAC, Kato-Katz and ether-concentration techniques failed to accurately detect threadworm larvae, and hence, the Koga agar plate remains the method of choice for this neglected parasite.

Branded in 2005, “neglected tropical diseases” have gained traction in terms of advocacy, interest for research, enhanced funding and political will for their control and eventual elimination. Starting with an initial set of 13 neglected tropical diseases – seven helminth, three bacterial and three protozoal infections – the list considerably expanded to more than 40 diseases that now also includes viral, fungal and ectoparasitic infections. In this review, we provide a comprehensive overview of the neglected tropical diseases, their causative agents and the current geographical distribution, including their importance for the general practitioners seeing returning travellers and migrants in Switzerland. We characterise the most important of the neglected tropical diseases in terms of at-risk population, estimated number of infections, annual mortality rates and global burden, including current knowledge gaps. With an emphasis on neglected tropical diseases due to helminths, protozoa and ectoparasites, we review common diagnostic methods and current recommendations for treatment at the population level and the individual patient, thereby juxtaposing the situation in highly endemic countries on one side, with Switzerland on the other. We highlight the clinical presentation and management of the neglected tropical diseases in general and then elaborate on two examples, strongyloidiasis and leptospirosis. Our review provides a global perspective of neglected tropical diseases and we hope that it will prove useful for the general practitioner and clinician in Switzerland and elsewhere to enhance their suspicion index, differential diagnosis, clinical management and treatment, including referral to specialised clinics and laboratories when need be.

Sensitive diagnostic tools are crucial for an accurate assessment of helminth infections in low-endemicity areas. We examined stool samples from Tanzanian individuals and compared the diagnostic accuracy of a real-time polymerase chain reaction (PCR) with the FLOTAC technique and the Kato–Katz method for hookworm and the Baermann method for Strongyloides stercoralis detection. Only FLOTAC had a higher sensitivity than the Kato–Katz method for hookworm diagnosis; the sensitivities of PCR and the Kato–Katz method were equal. PCR had a very low sensitivity for S. stercoralis detection. The cycle threshold values of the PCR were negatively correlated with the logarithm of hookworm egg and S. stercoralis larvae counts. The median larvae count was significantly lower in PCR false negatives than true positives. All methods failed to detect very low-intensity infections. New diagnostic approaches are needed for monitoring of progressing helminth control programs, confirmation of elimination, or surveillance of disease recrudescence.

Elimination of schistosomiasis as a public health problem and interruption of transmission in selected areas are key goals of the World Health Organization for 2025. Conventional parasitological methods are insensitive for the detection of light-intensity infections. Techniques with high sensitivity and specificity are required for an accurate diagnosis in low-transmission settings and verification of elimination. We determined the accuracy of a urine-based up-converting phosphor-lateral flow circulating anodic antigen (UCP-LF CAA) assay for Schistosoma haematobium diagnosis in low-prevalence settings in Zanzibar, Tanzania. A total of 1,740 urine samples were collected in 2013 from children on Pemba Island, from schools where the S. haematobium prevalence was <2%, 2–5%, and 5–10%, based on a single urine filtration. On the day of collection, all samples were tested for microhematuria with reagent strips and for the presence of S. haematobium eggs with microscopy. Eight months later, 1.5 ml of urine from each of 1,200 samples stored at -20°C were analyzed by UCP-LF CAA assay, while urine filtration slides were subjected to quality control (QCUF). In the absence of a true ‘gold’ standard, the diagnostic performance was calculated using latent class analyses (LCA). The ‘empirical’ S. haematobium prevalence revealed by UCP-LF CAA, QCUF, and reagent strips was 14%, 5%, and 4%, respectively. LCA revealed a sensitivity of the UCP-LF CAA, QCUF, and reagent strips of 97% (95% confidence interval (CI): 91–100%), 86% (95% CI: 72–99%), and 67% (95% CI: 52–81%), respectively. Test specificities were consistently above 90%. The UCP-LF CAA assay shows high sensitivity for the diagnosis of S. haematobium in low-endemicity settings. Empirically, it detects a considerably higher number of infections than microscopy. Hence, the UCP-LF CAA employed in combination with QCUF, is a promising tool for monitoring and surveillance of urogenital schistosomiasis in low-transmission settings targeted for elimination. The World Health Organization aspires to eliminate snail fever (schistosomiasis) as a public health problem and to interrupt the transmission of this disease in selected areas by 2025. Efforts to achieve these goals are currently being intensified. As a result, the prevalence and intensity of infection will decline in many parts of the world. To detect light-intensity infections, diagnostic tools with a high sensitivity and specificity are needed. We assessed the accuracy of a method that is able to diagnose schistosomiasis via the detection of circulating anodic antigen (CAA) in urine. We examined 1,200 urine samples from children living on Pemba Island, Tanzania, a low-endemic area targeted for schistosomiasis elimination. We found that the CAA-test had a considerably higher sensitivity than conventional urine filtration microscopy and reagent strips that are widely used in schistosomiasis control programs. The empirical prevalence of infection with the parasite Schistosoma haematobium determined by the CAA-test was up to 10 times higher than that obtained by urine filtration. Our results suggest that the CAA-test—in combination with urine filtration—is a promising approach for the diagnosis of S. haematobium in low-transmission settings that are targeted for elimination.