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Background Today, a suitable vaccine has not yet been discovered to prevent Toxoplasma gondii infection. Therefore, prophylaxis can be suggested as the preferred approach to prevent toxoplasmosis. This study aims to evaluate the prophylactic effects of synthesized zinc nanoparticles (ZnNPs) using Lavandula angustifolia Vera., by microwave method on chronic toxoplasmosis in mice. Methods BALB/c Mice orally administrated with ZnNPs the doses of 32.5, 75, 150 mg/kg/day for two weeks. On the 15th day, the mice were intraperitoneally infected with the Tehran strain of T. gondii (25 tissue cysts). The mean diameter and the numbers of brain tissue cysts, as well as the mRNA levels of inducible nitric oxide synthesize (iNOs), and interferon-gamma (IFN-γ) in mice of each experimental group were evaluated. Results The synthesized ZnNPs represent a spherical form with a size ranging from 30 to 80 nm. The results revealed that oral administration of Zn NPs at the doses of 32.5 (p < 0.001) and 75 mg/kg/day (p < 0.001) for 14 days significantly reduced the mean number and diameter of the brain tissue cysts in tested mice. No T. gondii tissue cyst was observed after oral administration of Zn NPs at the doses of 150 mg/kg. Based on the results of Real-time PCR analysis, the expression level of IFN-γ and iNOs was significantly increased (p < 0.001) in mice treated with 32.5, 75, 150 mg/kg/day for two weeks. Conclusion The obtained findings of the current investigation exhibit the significant prophylactic effects of ZnNPs against chronic toxoplasmosis in mice; so that oral administration of ZnNPs the doses 32.5, 75, 150 mg/kg reduced the parasite load and even completely controlled the infection in mice. The results show that the ZnNPs had strengthened the innate immune system which could be the reason for its strong prophylactic effects. However, further in vivo and clinical investigations are required to confirm these results as well as other possible mechanisms that can trigger these pharmacological properties.

Innate and acquired immunity responses are crucial for viral infection elimination. However, genetic variations in coding genes may exacerbate the inflammation or initiate devastating cytokine storms which poses severe respiratory conditions in coronavirus disease-19 (COVID-19). Host genetic variations in particular those related to the immune responses determine the patients' susceptibility and COVID-19 severity and pathophysiology. Gene polymorphisms such as single nucleotide polymorphisms (SNPs) of interferons, TNF, IL1, IL4, IL6, IL7, IL10, and IL17 predispose patients to the severe form of COVID-19 or severe acute respiratory syndrome coronavirus-2 (SARS-COV-2). These variations mainly alter the gene expression and cause a severe response by B cells, T cells, monocytes, neutrophils, and natural killer cells participating in a cytokine storm. Moreover, cytokines and chemokines SNPs are associated with the severity of COVID-19 and clinical outcomes depending on the corresponding effect. Additionally, genetic variations in genes encoding toll-like receptors (TLRs) mainly TLR3, TLR7, and TLR9 have been related to the COVID-19 severe respiratory symptoms. The specific relation of these mutations with the novel variants of concern (VOCs) infection remains to be elucidated. Genetic variations mainly within genes encoding proinflammatory cytokines, cytokine receptors, and TLRs predispose patients to COVID-19 disease severity. Understanding host immune gene variations associated with the SARS-COV-2 infection opens insights to control the pathophysiology of emerging viral infections.

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Background However, broad adoption of herbal remedies for giardiasis is at present hampered by uncertain findings of investigation not always sufficiently powered. This study was aimed at systematically reviewing the existing literature in herbal medicines to treat giardiasis. Methods This review was carried out 06- PRISMA guideline and registered in the CAMARADES-NC3Rs Preclinical Systematic Review and Meta-Analysis Facility (SyRF) database. The search was performed in five databases which are Scopus, PubMed, Web of Science, EMBASE, and Google Scholar without time limitation for all published articles ( in vitro, in vivo , and clinical studies). The searched words and terms were: “ Giardia ”, “giardiasis”, “extract”, “essential oil”, “herbal medicines”, “anti- Giardia ”, “ In vitro”, “In vivo ”, “clinical trial” etc. Results Out of 1585 papers, 40 papers including 28 in vitro (70.0%), 7 in vivo (17.5%), 2 in vitro/ in vivo (5.0%), and 3 clinical trials (7.5%) up to 2020, met the inclusion criteria for discussion in this systematic review. The most widely used medicinal plants against Giardia infection belong to the family Lamiaceae (30.0%) followed by Asteraceae (13.5%), Apiaceae (10.5%). The most common parts used in the studies were aerial parts (45.0%) followed by leaves (27.4%) and seeds (7.5%). The aqueous extract (30.0%), essential oil (25.4%) and hydroalcholic and methanolic (10.5%) were considered as the desired approaches of herbal extraction, respectively. Conclusion The current review showed that the plant-based anti- Giardia agents are very promising as an alternative and complementary resource for treating giardiasis since had low significant toxicity. However, more studies are required to elucidate this conclusion, especially in clinical systems.