Determinants of Schistosoma mansoni transmission in hotspots at the late stage of elimination in Egypt

BACKGROUND

In certain settings, the prevalence and severity of schistosoma infection do not lessen despite repeated rounds of preventative chemotherapy; these areas are known as hotspots. This study aimed to investigate the role of human practices, besides environmental and malacological factors, in the maintenance of the Schistosoma mansoni infection transmission chain in hotspot areas in Egypt.

METHODS

This cross-sectional study was conducted between July and November 2019 in Kafr El-Sheikh Governorate, Egypt. A pre-designed structured interviewing questionnaire was used to collect humanitarian data. Stool samples were collected from children aged 6-15 years on three successive days and examined using the Kato-Katz technique. Simultaneously, water and snail samples were taken from watercourses surrounding houses. Snails were identified based on their shell morphology and structure and tested for cercaria shedding. Water samples were analyzed for their physicochemical and biological characteristics.

RESULTS

A total of 2259 fecal samples (1113 in summer and 1146 in fall) were collected from 861 children. About 46.9% of the participants were males, and 31.8% were aged 6-10 years. The prevalence of S. mansoni infection was higher during the summer than during the fall (19.1% vs 7.2%, respectively, P < 0.01). The intensity of infection (light, moderate, and heavy) during summer versus fall was (93.55 vs 89.38%, 6.45 vs 8.85%, and 0.00% vs 1.77%), respectively (P < 0.05). A higher prevalence of human infection was observed among males than females [OR = 1.63, 95% confidence interval (CI):1.10-2.40, P = 0.015], children aged 11-15 years than among their counterparts aged 6-10 years (OR = 2.96, 95% CI: 1.72-5.06, P < 0.001), and mothers with a low level of education (OR = 3.33, 95% CI: 1.70-6.52, P < 0.001). The main identified risk factors were contacting the main body of water-canal for washing clothes (OR = 1.81, 95% CI: 1.12-2.49, P = 0.015), land irrigation (OR = 2.56, 95% CI: 1.32-4.96, P = 0.004), water collection (OR = 2.94, 95% CI: 1.82-4.73, P < 0.001), bathing (OR = 2.34, 95% CI: 1.21-4.31, P = 0.009), and garbage disposal (OR = 2.38, 95% CI:1.38-4.12, P < 0.001). The count of Biomphalaria alexandrina was distinct between seasons (P < 0.01) in consistent with statistically significant differences in water temperature, salinity, turbidity, the total concentration of coliforms, depth, velocity, and water level (P < 0.01). The presence of grasses and duckweeds was significantly associated with snail infection (P = 0.00 l). Significant effects of water depth, pH, temperature, and total dissolved solids on snail count were also observed (P < 0.05).

CONCLUSIONS

The persistence of the infection is due to adoption of risky behaviors and environmental factors that enhance snail survival and infection. Schistosomiasis elimination in hotspots requires an integrated control approach that combines preventive chemotherapy with other complementary measures.

Medical undergraduates' contributions to publication output of world's top universities in 2013

BACKGROUND

Medical undergraduates' (UGs) involvement in research activities is thought to be mutually beneficial to students, their mentors and the scholarly productivity of their universities. However, most evidence in favor of such assumption relies on subjective measures such as the self-reported gains in skills or knowledge rather than robust objective estimates for assessing impact.

AIM

We aimed to objectively track and describe publications with UG co-authors-their proportion to the total publication output of world's top universities, their characteristics and their potential impact on biomedical literature.

METHODS

We contacted the corresponding authors of the 2013's Medline-indexed publications affiliated to world's top 10 universities to investigate if any of their co-authors was an UG. Articles with UG co-authors were further assessed to determine, along with other variables: the type of study design, field of the article, publishing journal and its impact factor (IF), and number of received citations.

RESULTS

Out of 25 152 publications, 2537 articles (10.1%) contained at least one UG co-author who was the first author in 635 papers (25%). Articles with UG co-authors were published in 1114 journals with a median IF of 3.661. Most UGs' co-authored publications (82.7%, n = 2098) were cited at least once within 1 year, for a median of three citations per article.

CONCLUSION

UGs contributed to one in every 10 publications affiliated to top universities. Their papers were published in journals with good IFs and received a fair number of citations, which would reflect the relatively good quality and impact of these articles.

Study of bilharzial uropathy by means of hippuran I131 extended renography

Renal, ureteral, and vesicle functions were evaluated in 209 patients with obstructive lesions of the ureter due to schistosomiasis haematobia (bilharziasis), using Hippuran I131 extended renography. High values for Tmax. and T 1/2 were noted for both kidneys irrespective of radiological diagnosis of a left- or right-sided lesion. A high percentage of residual vesicle urine was demonstrated in a number of patients with bilharzial uro-obstructive lesions. The incidence of vesicoureteral reflux in relation to different lesions was also correlated. The results of this study support the concept that urinary schistosomiasis is a progressive disease which affects mainly the urinary bladder and lower ureter. The data obtained demonstrate the efficacy of extended renography in assessing renal, ureteral, and vesical function in patients with bilharziasis.