Kato-Katz Technique Research Articles

Immunoinformatic predictions and characterization of Schistosoma mansoni peptides as candidates for immunodiagnostic

Schistosoma mansoni represents a significant etiological agent of schistosomiasis, a neglected tropical disease with a global distribution. Although the Kato-Katz technique is an effective diagnostic tool in areas with a high prevalence of the disease, it lacks sensitivity in regions with lower prevalence. The objective of this study was to identify and validate novel immunogenic peptide targets derived from the S. mansoni proteome. The initial set of 14,499 predicted sequences were obtained from the WormBase database, and it was filtered to 8,308 by removing proteins lacking start or stop codons, shorter than 100 amino acids, or with undetermined amino acids. The sequences were then cross-referenced for cross-reactivity and ranked based on B-cell immunogenicity, resulting in the selection of 442 peptides for synthesis and screening. Immunoblotting revealed 22 reactive peptides, with 15 exhibiting specificities for sera from individuals at the initial infection (T0) stage and five reactive to both T0 and post-treatment (30D) sera. Subsequently, 19 peptides were subjected to further validation through molecular weight assessment and synthesized for ELISA testing. The multi-peptide pool demonstrated a reactivity frequency of 54.5 % in infected individuals, which surpassed the reactivity frequencies observed for individual peptides. The six peptides exhibiting the highest reactivity were subsequently analyzed according to infection intensity. The multi-peptide pool exhibited the highest reactivity (65.2 %) in low-intensity cases. ROC curve analysis indicated that Peptide 15 demonstrated the highest sensitivity (78.79 %) and specificity (87.5 %), while the multi-peptide pool exhibited 67.65 % sensitivity and 81.82 % specificity. These findings highlight the potential of peptide-based diagnostics to enhance the detection and control of schistosomiasis.

Comparative Diagnosis of Schistosomiasis by Standard and Molecular Methods in Turan District of Kwande Local Government Area, Benue State, Nigeria

The study was carried out to compare the diagnosis of schistosomiasis by standard and molecular methods in the Turan District of Kwande LGA. A total of 682 samples were collected, 482 urine and 200 stool samples. The urine samples were filtered on Whatman filter No.3 paper for DNA extraction and amplification. The urine samples were also examined microscopically using centrifugation and the Kato-Katz method. Forty (40) samples of the filtered urine were randomly picked irrespective of being positive or negative by microscopy and amplified by Polymerase Chain Reaction (PCR). Chi-square and Fisher’s exact test were applied to determine the association of infection in relation to location and water contact activity. The Kappa coefficient was also applied to assess the degree of concordance between the diagnostic techniques. From the 482 urine samples analyzed, 111(23.0%) were infected with S. haematobium; and out of the 200 stool samples examined, 3(1.5%) were infected with S. mansoni. In comparison PCR established a prevalence of 12 (30.0%) for S. haematobium and 6 (15%) for S. mansoni. PCR also detected 3 (7.5%) co-infections with S. mansoni and S. haematobium. Concordance between centrifugation and PCR revealed an almost perfect agreement (κ = 0.81) while Kato-Katz and PCR showed a substantial agreement (κ = 0.63). Prevalence of urogenital schistosomiasis by location revealed the highest infection rate of 32 (29.4%) in Yaav, followed by Kumakwagh with prevalence of 31(24.8%) and lowest infection rate of 27 (20.4%) was observed in Mbadura. However, no significant difference was observed in the prevalence of urinary schistosomiasis between the different communities (χ² = 4.68, p = 0.20). The study revealed that detection of Schistosoma parasite-specific DNA in urine by PCR is an effective tool for the diagnosis of schistosomiasis than processing urine and stool by standard methods

Comparative Diagnosis of Schistosomiasis by Standard and Molecular Methods in Turan District of Kwande Local Government Area, Benue State, Nigeria

The study was carried out to compare the diagnosis of schistosomiasis by standard and molecular methods in the Turan District of Kwande LGA. A total of 682 samples were collected, 482 urine and 200 stool samples. The urine samples were filtered on Whatman filter No.3 paper for DNA extraction and amplification. The urine samples were also examined microscopically using centrifugation and the Kato-Katz method. Forty (40) samples of the filtered urine were randomly picked irrespective of being positive or negative by microscopy and amplified by Polymerase Chain Reaction (PCR). Chi-square and Fisher’s exact test were applied to determine the association of infection in relation to location and water contact activity. The Kappa coefficient was also applied to assess the degree of concordance between the diagnostic techniques. From the 482 urine samples analyzed, 111(23.0%) were infected with S. haematobium; and out of the 200 stool samples examined, 3(1.5%) were infected with S. mansoni. In comparison PCR established a prevalence of 12 (30.0%) for S. haematobium and 6 (15%) for S. mansoni. PCR also detected 3 (7.5%) co-infections with S. mansoni and S. haematobium. Concordance between centrifugation and PCR revealed an almost perfect agreement (κ = 0.81) while Kato-Katz and PCR showed a substantial agreement (κ = 0.63). Prevalence of urogenital schistosomiasis by location revealed the highest infection rate of 32 (29.4%) in Yaav, followed by Kumakwagh with prevalence of 31(24.8%) and lowest infection rate of 27 (20.4%) was observed in Mbadura. However, no significant difference was observed in the prevalence of urinary schistosomiasis between the different communities (χ² = 4.68, p = 0.20). The study revealed that detection of Schistosoma parasite-specific DNA in urine by PCR is an effective tool for the diagnosis of schistosomiasis than processing urine and stool by standard methods

Prevalence and intensity of Schistosoma mansoni infection, and contributing factors in Alamata district of Tigray Region, Northern Ethiopia.

Intestinal schistosomiasis caused by Schistosoma mansoni continues to be a significant public health problem in Ethiopia. This study investigated the prevalence and intensity of S.mansoni infection, and contributing factors in Alamata district of Tigray Region, Northern Ethiopia. A community-based cross-sectional study was conducted and 1762 participants were enrolled from five clusters in Alamata district. A questionnaire was used to collect socio-demographic data and risk factors. Stool samples were examined using Kato-katz technique to determine the prevalence and intensity of infection. The data were analyzed using SPSS version 25. Median, inter quartile range (IQR), mean, frequency, and percentage were used to descriptively summarize data. The Wilcoxon Mann-Whitney and Kruskal-Wallis tests were used to compare the differences in mean rank of egg load between different groups. Bivariate and multivariable logistic regression models were used to investigate the association between the odds of being infected with S.mansoni and the different socio-demographic and other factors. The strength of these associations was reported using odds ratio with corresponding 95% confidence intervals, and a P-value below 5% was used to report statistical significance. Out of 1762 residents included in the study 941 (53.4%) were females. The age varied from 5-80 years, with a median age of 25 years (IQR = 27), the overall prevalence of S.mansoni was 21.5% with males accounting for 26% (204/821) of the infections. The proportion of infection was higher among the age groups of 15-19 and 20-29 years at 32.7% and 33.1%, respectively. The mean egg count among the infected study participants was 146.82 eggs per gram of feces (epg) ± (243.17 SD). Factors significantly associated with increased odds of infection were living in Waja cluster (AOR:8.9; 95% CI, 3.5-23.2; P< 0.001); being in the age groups 10-14 (AOR:6.0, 95% CI: 3.1-11.7, P<0.001), 15-19 (AOR:5.8, 95% CI:2.8-12.2, P<0.001), and 20-29 (AOR:3.5, 95% CI:1.8-6.8; P<0.001) years; having direct contact with water while crossing river (AOR: 2.4, 95% CI: 1.5-3.8, P<0.001); and swimming (AOR: 1.4, 95% CI: 1.01-2.0, P = 0.035). The study indicates a notable S.mansoni burden in the area, driven by various risk factors. To effectively address this, enhancing diagnostics, implementing targeted mass drug administration, and conducting comprehensive health education campaigns on disease transmission routes are imperative.

Schistosoma mansoni and soil-transmitted helminthic infections and associated factors among pregnant women in Jimma Town, Southwest Ethiopia

BackgroundSchistosomiasis and soil-transmitted helminth (STH) infections occurring during pregnancy may pose adverse health consequences to the mother and the developing baby. This study aims to determine the prevalence of Schistosoma mansoni and STHs, and their association with adverse birth outcomes among pregnant women in Jimma Town.MethodsA cross-sectional study involving 314 pregnant women was conducted in Jimma Town, Southwest Ethiopia. The pregnant women were recruited from selected public health facilities during their antenatal care (ANC) visits from August to December 2021. Data on demographic characteristics and factors associated with S. mansoni and STH infections were collected using a pretested questionnaire. Moreover, during the third trimester, stool specimen of each pregnant woman was examined using Kato-Katz technique, and hemoglobin was measured using a HemoCue analyzer. Data on adverse birth outcomes were collected during delivery. Data were analyzed using STATA-MP_12 (StataCorp., TX, USA).ResultsThe overall prevalence of intestinal helminthic infections was 26.1%. Soil-transmitted helminths and S. mansoni were detected in 20.4% (95%CI: 15.9–24.8) and 5.7% (95%CI: 3.2–8.3) of the pregnant women, respectively. The magnitude of low birth weight was 6.4%, higher in those with late-term delivery and maternal anemia (p < 0.05). Maternal anemia was also associated with post-partum bleeding (p < 0.05). Pregnant women who carry out laundry activities in the river were significantly more infected by S. mansoni (AOR 10.7, 95% CI: 2.2–51.9).ConclusionsThis study sheds light on the burden of maternal STH and S. mansoni infections in Jimma Town. A quarter of the pregnant women were infected with STHs and S. mansoni. It is recommended that pregnant women in the area avoid washing clothes in the river to reduce the risk of S. mansoni infection. Screening for intestinal parasitic infections should be conducted for pregnant women living in endemic areas during their ANC follow-up.

COVID-19 vaccination survey and anti-SARS-CoV-2 IgG responses in a human cohort from Schistosoma mansoni-endemic villages in Mayuge District, Uganda: a cross-sectional study.

The coronavirus disease 2019 (COVID-19) pandemic has resulted in devastating health and economic consequences worldwide. Vaccination has been a central pillar for COVID-19 prevention and control. Understanding the immunomodulatory effects of helminth infections on COVID-19 vaccine-induced immune responses and vaccine efficacy is crucial to the development and deployment of effective vaccination strategies in low- and middle-income countries with a high prevalence of worms. In September 2022, we conducted a cross-sectional, population-based survey in five Schistosoma mansoni endemic villages in Mayuge District, Uganda (n = 450). The prevalence of schistosomiasis and soil-transmitted helminths was determined by the Kato-Katz (KK) technique on two stool samples collected from each participant. A subset of individuals (n = 204) were interviewed in a COVID-19 vaccination survey. IgG levels against the SARS-CoV-2 spike S1 subunit (anti-S1 IgG) were measured by enzyme-linked immunosorbent assay (ELISA) in collected serum samples. The overall schistosomiasis and hookworm prevalence rates in the five villages were 36.4% (166/450) and 36.9% (168/450), respectively. Within the cohort, 69.78% (314/450) of the subjects had a positive anti-S1 IgG response. COVID-19 vaccination coverage among the interviewed participants was 93.14% (190/204; 95% CI, 88.8% - 95.9%). However, 81% (154/190) of COVID-19 vaccinees had an anti-S1 IgG titre ≤200. In an adolescent group receiving a single dose of the BNT162b2 mRNA vaccine (n = 23), an inverse correlation was observed between anti-S1 IgG antibody level/titre and faecal egg count. Within the above group, anti-S1 IgG levels/titres were significantly lower in subjects with moderate or heavy S. mansoni infection (n = 5) than those in KK-negative individuals (n = 9). Although the acceptance rate of COVID-19 vaccination was high, the majority of participants received only a single vaccine dose and the overall anti-S1 IgG titres in confirmed vaccinees were low. Moderate-to-heavy schistosome infections blunted the antibody responses following vaccination with a single dose of BNT162b2. These observations confirm the necessity for a second COVID-19 vaccine dose for two-dose primary immunization series and call for implementation research that may inform the development of a 'treat and vaccinate' policy during vaccination roll-out in regions with heavy worm burdens.

Prevalence and Sociodemographic Risk Factors of Soil-Transmitted Helminths in Rural Communities Living in Endemic Foci of Onchocerciasis in Southern Gabon.

This prospective survey determined the prevalence and intensity of infections due to geohelminths and the associated risk factors in five onchocerciasis-endemic communities in Gabon between January and February 2020. Onchocerciasis endemicity was confirmed by Ov16 IgG testing. STHs were detected using the Kato-Katz techniques. Prevalence and parasite density were analyzed according to age, sex, and onchocerciasis endemicity. STHs were found in 64.8% of participants and were more common in hypoendemic (80.9%) and hyperendemic (63.9%) onchocerciasis communities (p < 0.01). Ascaris lumbricoides (65.5%), Trichuris trichiura (57.1%), and hookworms (17.3%) were prevalent in areas hypoendemic for onchocerciasis (p = 0.04). Male participants were more often infected by hookworms. Adults were more frequently infected by STHs (75.9%) than elders, who were the least infected (39.3%) (p < 0.01). Participants living in sporadic onchocerciasis areas frequently but not significantly harbored a moderate ascariasis load (6960.0 (1068.0-9492.0) eggs per gram) (p = 0.4). The highest parasite density was observed among participants aged 20-45 years (15,336.0 (3888.0-35,028.0)). A low T. trichiuria prevalence was found in all communities. STHs are highly prevalent in hypoendemic and hyperendemic areas and adults. An integrated combined approach of STH and onchocerciasis elimination through efficacious mass drug administration targeting all age groups should be considered.

Strong association between high burden of soil-transmitted helminthiasis and household transmission among Malaysian Negritos, urging anthelmintic treatment beyond children

The Orang Asli (OA), Malaysia’s indigenous minority, continue to experience ongoing soil-transmitted helminth (STH) infections despite efforts including the Resettlement Programme (RPS). This study explores STH epidemiology and associated risks of moderate-to-heavy infections among 259 indigenous Negritos across four states in Peninsular Malaysia. Stool samples, anthropometrics, haemoglobin levels (finger-prick) and sociodemographic and environmental-sanitation factors via pretested questionnaires were collected. Parasitological examinations (direct faecal smear, formol-ether concentration, and Kato-Katz techniques) were thoroughly performed. The study revealed a 63.3% overall STH prevalence, with Trichuris trichiura (57.9%) being the most common, followed by Ascaris lumbricoides (35.5%) and hookworm (8.9%). Moderate-to-heavy infections were observed in 39.3% for T. trichiura and 48.9% for A. lumbricoides, with mixed infections of these two species being the most prevalent (50.6%). The risk for moderate-to-heavy infection increased significantly if other household members were infected (P < 0.001). Adults and adolescents also showed high infection rates, with no significant differences with children’s groups. These findings emphasize the need for anthelmintic treatment across all age groups and strategize local policies targeting older groups of the OA community to control ongoing transmission and reduce the STH burden and protect the future well-being of OA children, who deserve a healthier future.

Enhanced detection of Opisthorchis viverrini infection: A comparative evaluation of modified one-step FECT and conventional diagnostic methods in low-intensity setting

The formalin-ethyl acetate concentration technique (FECT) is one of the most sensitive diagnostic method not only for all helminths, but also for Opisthorchis viverrini infections in stool examinations. However, it remains a diagnostic problem for light infections. We modified the one-step FECT to determine the low-intensity of O. viverrini infection and compared with various conventional detection methods. The study utilized 160 egg-positive and 160 randomly negative stool samples for O. viverrini eggs by conventional FECT (cFECT) to compare the methods, including the simple smear, the Kato-Katz method, the two commercial stool examination kits, and the one-step FECT. Our results showed that the one-step FECT method had the highest sensitivity (95.6 %), followed by cFECT (87.9 %), the Kato-Katz (55.5 %), Aquisfek SF-FIX (48.3 %), simple smear (42.3 %), and Mini Parasep® SF (35.1 %). The ability of one-step FECT exhibited better ability to detect low parasite intensities compared to the cFECT (18 eggs per gram (e.p.g.) versus 34 e.p.g.) and the other conventional diagnostic methods. In addition, the investigation of O. viverrini infection in endemic regions in northeastern Thailand based on 3900 fecal samples revealed that the one-step FECT with an intensity of 66.8 e.p.g. (range 18–226) was significantly higher in sensitivity than cFECT, which had an intensity of 58.0 e.p.g. (range 34–214). Interestingly, fecal samples with less than 50 e.p.g. could not be detected by cFECT in 67 % of cases, and 69 out of 3900 samples were negative. In conclusion, one-step FECT improves the detection of low-intensity O. viverrini infection, which is suitable for parasites screening, especially for low-intensity infections in the community.

Evaluation of the diagnostic techniques in the detection of hookworm infestation among school children in Ethiopia: Cross-sectional study design

BackgroundHookworm infestation is an important public health concern especially in regions with poor sanitation and limited resources. In healthcare institutions in Ethiopia, wet mount microscopy with low performance has been used as the sole diagnostic technique. Sensitive diagnostic methods are essential for the proper identification of hookworm infection in national strategies for hookworm prevention and management. Thus, the objective of the article was to evaluate the performance of diagnostic techniques in the detection of hookworm infestation among school children in the Gozamin district, Northwest Ethiopia. MethodsA cross-sectional study with 530 school children was conducted from February to April 2022 in Ethiopia. The study participants were selected by using systematic random sampling technique. Direct wet mount (DWM), Richie’s, Kato-Katz (KK), and spontaneous tube sedimentation (STS) diagnostic techniques were utilized to process the stool samples. The data were entered into the Epi-data version 4.2 and the data was analyzed using SPSS version 25.0. The sensitivity, specificity, predictive values and test efficiency of the test were calculated with respect to the Composite Reference Standard (CRS) as the reference method. The degree of agreement with the methods of diagnosis was assessed by the Kappa value. ResultsThe overall prevalence of hookworm was 34.9 %. The detection rate of STS, Richie’s, KK and DWM techniques in hookworm detection was 30.2 %, 27.0 %, 22.3 % and 15.1 %, respectively. The sensitivity and test efficiency of STS to detect hookworm were 86.5 % and 95.3 %, for Richie’s 77.3 % and 92.1 %, for KK 63.8 % and 87.4 %, for DWM method 43.2 % and 80.2 %, respectively. The agreement of STS, Richie’s, KK and DWM techniques with CRS were perfect (κ = 0.893), perfect (κ = 0.816), substantial (κ = 0.696) and moderate (κ = 0.498), respectively in detecting hookworm parasites. ConclusionThe prevalence of hookworm among school children was high. The STS method is superior to other methods for detecting hookworm infections. The Richie’s technique was more successful in detecting the hookworm parasite than the KK and DWM techniques. It is important to implement the STS technique in routine diagnostic methods and in endemic areas of hookworm infection because it cheaper, easy to perform, and identifies a wide range of parasitic species.

Risk factors for Ascaris lumbricoides infection and its association with nutritional status and IQ in 14-Year old adolescents in Chitwan, Nepal

Inconsistent results have been obtained from studies investigating the association between soil-transmitted helminths (STHs) and nutritional status and cognitive outcomes. This study aimed to investigate the influence of STHs and nutritional status on the intelligence quotient (IQ) of adolescents in the Chitwan Valley, Nepal. In this birth cohort study from the Chitwan district of Nepal, 74 cohort participants were followed up after 14 years. The presence and egg density of the STHs were investigated following the Kato–Katz method. Full-scale IQ was evaluated using the Wechsler Abbreviated Scale of Intelligence-II (WASI-II). Multivariate regression analysis was also conducted to examine the associations of STHs and nutritional status with IQ scores, adjusting for adverse childhood experiences (ACE) and demographic and socioeconomic factors. The only STHs detected was for Ascaris lumbricoides, which was detected in 16% (12/74) of the study participants. Similarly, 16% (12/73) of participants reported undernutrition (body mass index (BMI) Z score<-2SD), and 33% (25/74) of participants had a developmental deficit (WASI II FSIQ < 69). There were no significant associations between the presence of A. lumbricoides or egg density and IQ scores. However, undernutrition (BMIZ<-2SD) increased the odds of a developmental deficit according to both univariate and adjusted multivariate models [i.e., adjusted odds ratio (aOR) 9.41; 95% CI (2.23 to 39.80)]. While the study primarily examines the association of STHs and nutritional status with IQ, it is important to note that adolescents with educated mothers or higher incomes also showed better cognitive development. The prevalence of undernutrition and associated developmental deficits characterized by an IQ < 69 was alarmingly high in this cohort of adolescents from Chitwan, Nepal. Despite the high prevalence of A. lumbricoides, its infection was not identified as significantly associated with cognition. However, it is noteworthy that a consistent favorable impact of an enriching postnatal environment, approximated by maternal education and family income, may improve neurodevelopmental indicators.

Soil-transmitted helminthes prevalence, intensity, and associated factors among school-aged children in the communities of west Guji Zone, South Ethiopia

BackgroundSoil-transmitted helminth (STH) infections are a major health problem among school-age children in developing countries. Prolonged exposure to STH can lead to reduced physical fitness, stunted growth, anemia, bowel obstruction, and cognitive impairments. ObjectiveTo determine the prevalence, intensity, and associated risk factors of soil-transmitted helminths among school-aged children in the west Guji Zone, South Ethiopia. MethodsA community-based cross-sectional study was conducted among 614 randomly selected school-aged children in selected districts of the West Guji zone from February to March 2023. A pre-tested questionnaire was used, and samples were examined by wet mount and Kato-Katz techniques. Data entry was analyzed using SPSS. Binary and multivariable logistic regression analyses were applied to identify potential associated factors. P-value<0.05 was declared as statistical significance. ResultsThe overall prevalence of STH was 32.7 % (95 % CI: 28.4%–35.8 %). Ascaris lumbricoides 95 (11.1 %) was the most common identified STH. Most school-age children, 74 %, were infected with a mild intensity of soil-transmitted helminths (STH). The mean egg count for Ascaris lumbricoides, Trichuris trichiura, and hookworms was 4465.4, 563.7, and 958.9, respectively. The study found significant associations with several factors, including washing hands with soap after using the toilet (AOR: 2.8, 95 % CI: 1.8–4.6), trimming fingernails (AOR: 4.6, 95%CI: 2.9–7.1), and the habit of wearing shoes (AOR: 2, 95%CI: 1.4–2.9) ConclusionSoil-transmitted helminths infection prevalence is high among school-aged children of the study areas. To prevent and control these infections, comprehensive health education should focus on the importance of hygienic practices, improved sanitation, and regular deworming programs for school-aged children.

Evaluation of a novel biplex rapid diagnostic test for antibody responses to Loa loa and Onchocerca volvulus infections.

Endemic to Central Africa, loiasis, caused by the vector-borne worm Loa loa, affects approximately 10 million individuals. Clinical manifestations include transient angioedema (Calabar swellings), migration of the adult worm under the eye conjunctiva (eye worm) and less specific general symptoms. Loiasis presents a significant public health challenge because L. loa-infected individuals can develop serious adverse events after taking ivermectin, the drug used to combat onchocerciasis. In this context, alternative interventions and rigorous diagnostic approaches are needed. Diagnosing loiasis is challenging because its main clinical manifestations are sporadic and non-specific. The definitive diagnosis relies on identifying adult worms migrating beneath the conjunctiva, or microfilariae (pre-larvae) in blood smears. However, "occult loiasis" (infection without blood microfilariae) is frequent. Serological rapid antibody diagnostic tests (ARTs) can provide an alternative diagnostic method. We compared a novel ART simultaneously targeting onchocerciasis (IgG4 to Ov-16 and OvOC3261, test line 1) and loiasis (IgG4 to L1-SXP-1, test line 2), called IgG4-SXP-1 biplex test) to the already established Loa-ART (all IgG isotypes to Ll-SXP-1, called pan-IgG-SXP-1 test). Blood samples underwent both ARTs, read qualitatively and semi-quantitatively. Additionally, blood smears, skin snips, Kato-Katz method for soil-transmitted helminthiases identification and eosinophilia measurements were performed. Questionnaires gathered demographic details and loiasis-related signs. ARTs performance was compared using specific loiasis-related signs and microfilaremia as references. Discordances between the two ARTs were investigated using logistic regression models. Out of 971 participants, 35.4% had L. loa microfilaremia, 71.9% had already experienced loiasis-related signs, 85.1% were positive in the pan-IgG-SXP-1 test and 79.4% were positive in the IgG4-SXP-1 biplex test. In the microfilariae-positive population, the sensitivity of the rapid tests was 87.4% for the pan-IgG-SXP-1 test and 88.6% for the prototype IgG4-SXP-1 biplex test. Sensitivity was similar for both ARTs when using eye worm or Calabar swelling as references, but diagnostic performance varied based on microfilaremia levels and occult loiasis. Overall, IgG4-SXP-1 biplex test demonstrated a sensitivity of 84.1% and specificity of 47.6% for loiasis compared to the pan-IgG-SXP-1 test, leading to a Kappa coefficient estimated at 0.27 ± 0.03 for the qualitative results of the 2 ARTs. In the group that tested positive with the Pan-IgG test but negative with the IgG4-specific test, there was a lower prevalence of STH infection (p = 0.008) and elevated eosinophilia (p<0.001) compared to the general tested population. The sensitivity of each test was good (84-85%) but the diagnostic agreement between the two ARTs was poor, suggesting that IgG and IgG4 antibody responses should be interpreted differently. The assessment of the innovative rapid diagnostic IgG4-SXP-1 biplex test, designed for onchocerciasis and loiasis, shows encouraging sensitivity but underlines the necessity for further in vitro assessment.

Modeling transmission mechanism to infer treatment efficacy of different drugs and combination therapy against Trichuris trichiura

Trichuris trichiura is one of four soil-transmitted helminth species that, collectively, are responsible for a considerable public health burden. The World Health Organization recommends preventive chemotherapy as the main intervention to eliminate soil-transmitted helminthiasis as a public health problem. Clinical trials estimated the efficacy of different drugs and treatment regimen against T. trichiura and other soil-transmitted helminth species, whilst meta-analyses and modeling efforts were conducted to determine the most efficacious drugs and drug combinations. Of note, the diagnostic error was often neglected, and hence, cure rates (CRs) might be overestimated. We developed a Bayesian model, which estimates drug efficacy against T. trichiura, taking into account the transmission mechanism and the diagnostic error. The model was fitted to individual-level egg count data from an ensemble of seven trials with 29 treatments. We estimated the ‘true’ CRs, which were consistently lower than those reported in the literature. In our analysis, the treatment with the highest CR was combination therapy of albendazole plus pyrantel pamoate plus oxantel pamoate with a CR of 79% and an egg reduction rate (ERR) of 91%. Albendazole plus oxantel pamoate showed the highest ERR of 97% and a CR of 69%. Additionally, we estimated the intensity-dependent sensitivity of the Kato-Katz technique. For 24 eggs per gram of stool, the sensitivity was around 50% for a single Kato-Katz thick smear and increased to almost 70% for duplicate Kato-Katz thick smears. Combination therapies against soil-transmitted helminthiasis should be considered and the evaluation of infection intensity in low transmission settings via multiple Kato-Katz thick smears is recommended.

Control and elimination of Schistosoma mansoni infection in adult individuals on Ukerewe island, northwestern Tanzania: baseline results before implementation of intervention measures

BackgroundCommunities living along the shoreline and on the islands of Lake Victoria in northwestern Tanzania remain endemic for schistosomiasis and suffer from the life-threatening morbidities associated with the disease. Nevertheless, the control measures particularly the mass drug administration do not cover the adult population. The current project on Ukerewe island aims to close this gap by involving adult community members in the control program. Here we report the baseline results of S. mansoni infection and associated hepatosplenic morbidities and factors before implementing the project activities.MethodsA cross-sectional analytical study was conducted with 4,043 participants aged ≥ 18 years living in 20 villages on Ukerewe island, northwestern Tanzania. Individual stool and urine samples were collected and examined using the Kato-Katz (KK) technique and point-of-care circulating cathodic antigen testing(POC-CCA) to identify S. mansoni eggs and antigens, respectively. All study participants underwent ultrasound evaluation of S. mansoni hepatosplenic morbidities using the Niamey protocol. Rapid diagnostic tests were used to diagnose HIV infection, hepatitis C and chronic hepatitis B. A questionnaire was used to collect demographic data and reported clinical symptoms of study participants.ResultsA total of 4,043 participants took part in the study, of which 49.7% (n = 2,009) and 50.3% (n = 2,035) were male and female, respectively. The overall prevalence of S. mansoni infection was 30.4% (95%CI:29.0-31.9%) and 84.7% (95%CI:83.3–85.9%), respectively, based on the KK technique and the POC-CCA test. The geometrical mean eggs per gram of faeces (GMepg) was 105.3 (95%CI:98.7-112.3% GMepg) with 53.9%, 32.4% and 13.7% of the participants having mild, had moderate and severe intensity of infection. The prevalence of hepatitis C, HIV, and hepatitis B was 0.4%, 2.2% and 4.7%, with 0.2%, 2.2% and 5.4% of the infected individuals coexisting with S. mansoni infection. The prevalence of splenomegaly, periportal fibrosis, hepatomegaly, and portal vein dilatation was 40.5%(95%CI: 38.8–42.1%), 48.1%(95%CI:64.4–49.7%), 66.2%(95%CI:4.6–67.7%) and 67.7%(95%CI:66.2–69.2%), with their prevalence varying depending on the demographic information and infection status of the participants. Other detectable ultrasound-related morbidities included ascites (1.7%), collateral veins (18.3%) and gall bladder wall thickness (40.4%). Age groups, gender, reported clinical characteristics, reported non-use of the drug praziquantel, liver imaging pattern, and place of residence remained independently associated with hepatosplenic morbidities.ConclusionThe current study setting is endemic for S. mansoni infection and the population has a high prevalence of the disease associated hepatosplenic morbidities characterized by hepatomegaly, splenomegaly, ascites, gall bladder wall thickening, periportal fibrosis and portal vein dilatation. Several demographic, clinical and epidemiological circumstances remained independently associated with S. mansoni infection and associated morbidities. These findings call for integrative intervention efforts, starting with whole community MDA that includes all out of schools community members.

Detection of the carcinogenic liver fluke, Opisthorchis viverrini: comparison of two coprological methods versus the automatic feces analyzer.

Liver fluke infection, particularly Opisthorchis viverrini, poses a significant public health risk in Thailand, where it is closely associated with cholangiocarcinoma and contributes to substantial mortality in the northeastern region. Diagnosis of this condition employs various parasitological approaches. This research aims to compare the diagnostic accuracy of three parasitological techniques: the Kato Katz technique (KKT), the formalin-ethyl acetate concentration technique (FECT), and the Fully Automatic Feces Analyzer (FAFA) for O. viverrini identification. A total of 455 fecal specimens were collected from rural areas across five provinces in northeastern Thailand. The specimens were processed according to each method and examined through microscopy for KKT and FECT, and by utilizing an artificial intelligence-based machine for FAFA. Data analysis was conducted to assess parasitic infection rates and observe diagnostic accuracy. The results revealed a parasitic infection rate of 19.34%, with the majority of infections attributed to O. viverrini (18.02%), followed by Strongyloides stercoralis (0.88%). FECT exhibited the highest positive detection of O. viverrini eggs (16.48%), followed by FAFA (10.55%), and KKT (8.57%), respectively. Statistical analysis indicated sensitivity and specificity values for O. viverrini detection by KKT (100% and 89.21%), FECT (98.67% and 97.63%), and FAFA (97.92% and 91.15%). The positive predictive value, negative predictive value, and kappa were reported for FECT (89.16%, 99.73%, 0.92), FAFA (56.63%, 99.73%, 0.67), and KKT (45.78%, 100%, 0.58). Additionally, the preparation time for KKT, FECT, and FAFA was 30, 15, and 10 min, respectively. In conclusion, this study highlights FECT, KKT, and FAFA as comparably sensitive in diagnosing O. viverrini. The FAFA machine emerges as a potentially valuable tool for detecting O. viverrini and other parasitic infections, showcasing promise for clinical use. The findings provide valuable insights into the diagnostic landscape and underscore the potential of FAFA in enhancing efficiency and accuracy in parasitological assessments.

Prevalence and Risk Factors of Intestinal Parasitic Infections among Schoolchildren in Katsina Metropolis, Katsina State, Nigeria

Intestinal Parasitic Infections (IPIs) are significant causes of morbidity, particularly among school-aged children. This cross-sectional study was conducted to assess the prevalence and risk factors of intestinal parasitic infections among schoolchildren in Katsina Metropolis, Katsina State, Nigeria. A total of 420 schoolchildren from five randomly selected primary schools were enrolled for the study. Socio-demographic data were collected using structured questionnaires administered to both the children and their parents. Stool samples were analyzed using the Kato-Katz and direct wet-mount techniques to identify the presence of parasitic infections. The overall prevalence of intestinal parasitic infections was found to be 33.6%. The most prevalent parasite was Ascaris lumbricoides, detected in 28.0% of the children, and followed by Giardia lamblia (23.3%), Hookworm (22.8%), Entamoeba coli (19.5%), and Trichuris trichiura (6.6%). The prevalence was higher in males (37.1%) compared to females (30.1%). Children aged 6-9 years showed a significantly higher prevalence (38.0%) than those aged ≥10 years (30.0%) (P&lt;0.05). The key risk factors identified included family size, dietary habits, lack of toilet facilities, drinking water sources and the educational status of parents. The study indicates that STHs and intestinal protozoa infections remain prevalent among schoolchildren in Katsina Metropolis, posing a substantial public health challenge. Addressing this issue requires increased public awareness, improved sanitation in schools, and the implementation of school-based deworming programs.

Persistent transmission of soil-transmitted helminths despite 16 years of uninterrupted Mebendazole- and ivermectin-based preventive chemotherapy in the Lomie Health District (East Region, Cameroon): The emergency of complementary control strategies.

The control of the Soil-Transmitted Helminths (STH) infections primarily relies on the school-based Preventive Chemotherapy (PCT) with mebendazole. Given the efficacy of ivermectin on STH, the control of the latter is expected to be potentialized in areas where ivermectin is also distributed for onchocerciasis and/or lymphatic filariasis control/elimination. This study aimed to assess the prevalence and intensity of STH in the Lomie Health District where annual school-based deworming campaigns and community-directed treatments with Ivermectin have been underway for almost two decades. A quantitative cross-sectional study was conducted in 10 schools of the Lomie Health District, East Region, Cameroon. Stool samples were collected from school-aged children and analysed using the Kato-Katz technique. Semi-structured questionnaires were administered to enrolees to assess compliance with water, sanitation, and hygiene (WASH). Of the 491 children (median age: 9 years; IQR: 7-10) enrolled, 83.9% (95% CI: 80.3-87.1) were infected with at least one STH species. Trichuris trichiura was the predominant species (78.5%), and no hookworm was found. The prevalence trend slightly decreased between 1987 and 2010 (~8%) and remained unchanged since 2010 (p-value = 0.05). Overall, 46.8% and 41.8% of children were heavy-to-moderately infected with Ascaris lumbricoides and T. trichiura. Poor hand hygiene (OR: 2.24, 95% IC: 1.4-3.4, p-value = 0.0002) and the use of river as a source of drinking water (OR: 14.8, 95% IC: 6.9-33.3, p-value = 0.0001) were the main risk factors associated with the STH infection in Lomie Health District. The persistent high prevalence and intensity of STH infection despite 16 years of mebendazole-based PCT and expected collateral impact of ivermectin mass distribution, points to plausible implementation gaps, poor compliance to WASH or sub-optimal efficacy of the anthelminthics used. This study highlights the need to further assess the cause of the persistent high prevalence and implement context-adapted control measures in order to curb STH transmission.

Socio-economic risk factors for intestinal helminthiases in selected endemic communities in Mindanao, the Philippines: a cross-sectional study

Abstract Background Parasitic neglected tropical diseases (NTDs) or ‘infectious diseases of poverty’ continue to affect the poorest communities in the world, including in the Philippines. Socio-economic conditions contribute to persisting endemicity of these infectious diseases. As such, examining these underlying factors may help identify gaps in implementation of control programs. This study aimed to determine the prevalence of schistosomiasis and soil-transmitted helminthiasis (STH) and investigate the role of socio-economic and risk factors in the persistence of these diseases in endemic communities in the Philippines. Methods This cross-sectional study involving a total of 1,152 individuals from 386 randomly-selected households was conducted in eight municipalities in Mindanao, the Philippines. Participants were asked to submit fecal samples which were processed using the Kato-Katz technique to check for intestinal helminthiases. Moreover, each household head participated in a questionnaire survey investigating household conditions and knowledge, attitude, and practices related to intestinal helminthiases. Associations between questionnaire responses and intestinal helminth infection were assessed. Results Results demonstrated an overall schistosomiasis prevalence of 5.7% and soil-transmitted helminthiasis prevalence of 18.8% in the study population. Further, the household questionnaire revealed high awareness of intestinal helminthiases, but lower understanding of routes of transmission. Potentially risky behaviors such as walking outside barefoot and bathing in rivers were common. There was a strong association between municipality and prevalence of helminth infection. Educational attainment and higher “practice” scores (relating to practices which are effective in controlling intestinal helminths) were inversely associated with soil-transmitted helminth infection. Conclusion Results of the study showed remaining high endemicity of intestinal helminthiases in the area despite ongoing control programs. Poor socio-economic conditions and low awareness about how intestinal helminthiases are transmitted may be among the factors hindering success of intestinal helminth control programs in the provinces of Agusan del Sur and Surigao del Norte. Addressing these sustainability gaps could contribute to the success of alleviating the burden of intestinal helminthiases in endemic areas.

Baseline gut microbiota diversity and composition and albendazole efficacy in hookworm-infected individuals

Soil-transmitted helminth (STH) infections account for a significant global health burden, necessitating mass drug administration with benzimidazole-class anthelmintics, such as albendazole (ALB), for morbidity control. However, ALB efficacy shows substantial variability, presenting challenges for achieving consistent treatment outcomes. We have explored the potential impact of the baseline gut microbiota on ALB efficacy in hookworm-infected individuals through microbiota profiling and machine learning (ML) techniques. Our investigation included 89 stool samples collected from hookworm-infected individuals that were analyzed by microscopy and quantitative PCR (qPCR). Of these, 44 were negative by microscopy for STH infection using the Kato-Katz method and qPCR 21 days after treatment, which entails a cure rate of 49.4%. Microbiota characterization was based on amplicon sequencing of the V3–V4 16S ribosomal RNA gene region. Alpha and beta diversity analyses revealed no significant differences between participants who were cured and those who were not cured, suggesting that baseline microbiota diversity does not influence ALB treatment outcomes. Furthermore, differential abundance analysis at the phylum, family and genus levels yielded no statistically significant associations between bacterial communities and ALB efficacy. Utilizing supervised ML models failed to predict treatment response accurately. Our investigation did not provide conclusive insights into the relationship between gut microbiota and ALB efficacy. However, the results highlight the need for future research to incorporate longitudinal studies that monitor changes in the gut microbiota related to the infection and the cure with ALB, as well as functional metagenomics to better understand the interaction of the microbiome with the drug, and its role, if there is any, in modulating anthelmintic treatment outcomes in STH infections. Interdisciplinary approaches integrating microbiology, pharmacology, genetics and data science will be pivotal in advancing our understanding of STH infections and optimizing treatment strategies globally.Graphical