Promastigotes of Leishmania braziliensis, L. donovani, L. major and L. mexicana recently derived from tissue amastigotes were cultured in Schneider's Drosophila medium supplemented with 20 % (v\v) heat-inactivated foetal calf serum and 25 µg gentamicin sulfate\ml at pH 5n5. These cultures produced more metacyclic promastigotes in their stationary-phase populations than others cultured at pH 7n0. Metacyclic promastigotes possessed a short ( 8 µm) and narrow ( 1n5 µm) cell body with a flagellum twice or more the length of the cell body. Promastigotes from acidic cultures were more resistant to complement-mediated lysis and more infective in vivo than those grown at neutral pH. These results demonstrate that induction of metacyclogenesis by acidic pH is a response conserved across a variety of species of Leishmania.

SARS-CoV-2 has spread throughout the world and become the cause of the infectious coronavirus disease 2019 (COVID-19). As low- and middle-income countries shift increasingly to focus on identifying and treating COVID-19, questions are emerging about the impact this shift in focus will have on ongoing efforts to control other infectious diseases, such as malaria. This review discusses how the spread of SARS-CoV-2 in low- and middle-income countries might impact these efforts, focusing in particular on the effects of co-infection and the use of antimalarial drugs used to treat malaria as therapeutic interventions for COVID-19.

COVID-19 crisis had a huge impact on education and academics. Besides, it might have generated public fear and worry. All these factors might affect students’ performance and wellbeing and might increase stress levels especially during exams.  Therefore, this study will investigate the impact of COVID-19 crisis on student’s exam anxiety and its relationship with other factors. A cross-sectional study was conducted by distributing exam anxiety survey electronically to Saudi universities bachelor students, two hundred and seventy-two students have responded to the survey.  The results have shown that both female and male student have high anxiety levels. And no significant correlation was found between any demographic data and anxiety level, except the gender, as female students have a higher anxiety level than male students. In conclusion, COVID-19 might had generated a high exam anxiety level, especially in female students. Therefore, facilitating initiatives might be considered to improve students’ performance during this crisis.

SummaryNeuro-immune interactions, particularly those driven by neuropeptides, are increasingly implicated in immune responses. For instance, triggering calcium-channel transient receptor potential vanilloid 1 (TRPV1) on sensory nerves induces the release of calcitonin-gene-related peptide (CGRP), a neuropeptide known to moderate dendritic cell activation and T helper cell type 1 polarization. Despite observations that CGRP is not confined to the nervous system, few studies have addressed the possibility that immune cells can respond to well-documented 'neural' ligands independently of peripheral nerves. Here we have identified functionally relevant TRPV1 on primary antigen-presenting cells of the spleen and have demonstrated both calcium influx and CGRP release in three separate strains of mice using natural agonists. Furthermore, we have shown down-regulation of activation markers CD80/86 on dendritic cells, and up-regulation of interleukin-6 and interleukin-10 in response to CGRP treatment. We suggest that dendritic cell responses to neural ligands can amplify neuropeptide release, but more importantly that variability in CGRP release across individuals may have important implications for immune cell homeostasis.

The degree of awareness about parasitic diseases among intermediate, secondary, and university students was investigated. Three thousand and two hundred male and female students at different levels of studies from the city of Jeddah, Saudi Arabia were asked to fill a questionnaire to estimate their degree of awareness about parasites and parasitic infections. Students studying in faculties related to the medical field were excluded. Questionnaires were analyzed and the mean level of awareness about parasites and parasitic infections among students was 2.9 (±1.4) of 6. Nationality, age, level of study, family income, and previous exposure to intestinal parasites had a statistically significant influence on awareness about parasitic disease (p<0.01). In conclusion, there is a below average level of awareness about parasites and parasitic diseases among students. Inoculating more information about parasites and parasitic diseases in school curricula will help in increasing the awareness level. The media can also be used more efficiently to provide more information and increase the level of awareness.