Intestinal schistosomiasis among preschool and school-aged children in a rural setting near Alexandria: initiative for elimination

Two Molecular Plasma-Based Diagnostic Methods to Evaluate Early Infection of Schistosoma japonicum and Schistosomiasis Japonica

The prevalence and infectious intensity of schistosomiasis japonica has decreased significantly in China in the past few decades. However, more accurate and sensitive diagnostic methods are urgently required for the further control, surveillance, and final elimination of the disease. In this study, we assessed the diagnostic efficacy of a real-time fluorescence quantitative PCR (qPCR) method and recombinase polymerase amplification (RPA) combined with a lateral-flow dipstick (LFD) assay for detecting early infections of Schistosoma japonicum and different infection intensities. The sensitivity of the qPCR at 40 days post-infection (dpi) was 100% (8/8) in mice infected with 40 cercariae, which was higher than in mice infected with 10 cercariae (90%, 9/10) or five cercariae (77.8%, 7/9). The results of the RPA-LFD assays were similar, with sensitivities of 55.6% (5/9), 80% (8/10), and 100% (8/8) in mice infected with 5, 10, and 40 cercariae, respectively. In goats, both the qPCR and RPA-LFD assays showed 100% (8/8) sensitivity at 56 dpi. In the early detection of S. japonicum infection in mice and goats with qPCR, the first peak in positivity appeared at 3-4 dpi, when the positivity rate exceeded 40%, even in the low infection, intensity mice. In the RPA-LFD assays, positive results first peaked at 4-5 dpi in the mice, and the positivity rate was 37.5% in the goats at 1 dpi. In conclusion, neither of the molecular methods produced exceptional results for the early diagnosis of S. japonicum infection. However, they were useful methods for the regular diagnosis of schistosomiasis in mice and goats.

Evaluation of faecal lactoferrin as a morbidity biomarker in Schistosoma mansoni infection

OBJECTIVE

Lactoferrin is an 80 KDa iron-binding glycoprotein that plays a significant role in the innate immune system and is considered to be an important microbicide molecule. This study aimed to assess the concentration of lactoferrin in Schistosoma mansoni-infected cases before and after praziquantel treatment.

METHODS

A cross-sectional study was carried out on 250 individuals aged from 5 to 30 years. Stool samples were examined for the presence of parasitic infections using Kato-Katz and formalin ethyl acetate techniques. All S. mansoni-positive cases were treated with praziquantel and stool samples were recollected 21 days later. Faecal lactoferrin level was determined before and after treatment.

RESULTS

The prevalence of S. mansoni infection was 14.4%. Among 36 participants infected with S. mansoni, the cure rate was 91.7%. A statistically significant difference in the mean lactoferrin level before and after treatment was detected (1648.95 pg/ml ± 656.5 vs. 1162.8 pg/ml ± 356.8). This difference was statistically significant in the middle and older age groups, in males and in the absence of coinfection with other parasites.

CONCLUSION

Lactoferrin could be a promising biomarker associated with S. mansoni infection, however, it could not be used to assess the severity of infection.

Performance of loop-mediated isothermal amplification (LAMP) for detection of Schistosoma mansoni infection compared with Kato–Katz and real-time PCR

The performance of loop-mediated isothermal amplification (LAMP) for detection of Schistosoma mansoni DNA from stool and urine samples in comparison with Kato–Katz and real-time polymerase chain reaction (PCR) was studied. After obtaining informed consent, 50 children participated in the present study and agreed to submit stool and urine samples. Stool samples were examined by Kato–Katz. Both real-time PCR and LAMP techniques were applied on stool and urine samples. The overall prevalence of S. mansoni was 46% in stool and urine samples as detected by the employed techniques, and 90% of cases had light infection intensity. The highest percentage of infection was diagnosed by real-time PCR (44%), followed by Kato–Katz (42%) and LAMP in the stool (36%), while the lowest percentages of infection were diagnosed by real-time PCR and LAMP in urine samples (24% and 14%, respectively). Kato–Katz, real-time PCR and LAMP showed 100% specificity where the sensitivity was 91.3%, 95.7% and 78.3%, respectively, in stool samples. Real-time PCR and LAMP showed lower sensitivity in urine samples. The LAMP assay is a promising technique for S. mansoni diagnosis in endemic countries of moderate and high-intensity infection. Yet, it needs further optimization, particularly in urine samples.