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Background Soil-transmitted diseases are caused by intestinal worms transmitted via various routes into the human body resulting in various clinical manifestations. This study aimed to investigate the socio-demographic factors contributing mainly to the prevalence of soil-transmitted helminths (STHs) among newly arrived laborers in Jeddah, Saudi Arabia. Methods A total of 188 stool specimens were collected and examined macroscopically and microscopically using different techniques. In addition, real-time PCR was used as a molecular tool to detect several STHs. The descriptive analysis was used to evaluate demographic data and categorical variables in association with STHs infection. Results Of all participants, the mean age was 26.08 ± 2.67 years, including 103 females and 85 males. A total of 86 (45.70%) were illiterate, followed by 60 (31.90%) of participants belonging to elementary level. STHs and other intestinal parasites were detected among 35 newly arrived laborers (18.61%). Nineteen cases (10.11%) were infected with STHs, including 15 cases with one STHs (four A. lumbricoides, four N. americanus, four T. trichiura, two S. stercoralis, one A. duodenale) and four cases with two STHs (two T. trichiura and N. americanus; one S. stercoralis and A. duodenale; one T. trichiura and S. stercoralis). High rates of STHs infection were detected among drivers (11.70%) followed by housemaids (11.20%), but with no significant association to occupation. Higher rates of STHs infection were detected among those used to walk on soil barefoot in their home countries before arriving in Jeddah. Conclusion This study found that none of the newly arrived expatriate laborers in Jeddah was aware of STHs. About 10% of them had infection with one or two STHs, mainly among newly arrived laborers from Asian countries. There is a need for awareness programs and regular screening for STHs and other intestinal parasites among newly arrived expatriate laborers.

BackgroundSchistosomiasis affects approximately 250 million people worldwide, with 200,000 deaths annually. It has been documented that the granulomatous response to Schistosoma mansoni (S. mansoni) oviposition is the root cause of progressive liver fibrosis in chronic infection, in 20% of the patients, and can lead to liver cirrhosis and/or liver cancer. The influence of helminths coinfection on schistosomiasis-induced liver pathological alterations remains poorly understood. Therefore, in this study, we investigated the effect of Trichinella spiralis (T. spiralis) infection on S. mansoni-induced hepatic fibrosis.Materials and methodsThirty adult male Balb-c mice were divided into three groups. Group 1 was left uninfected; group 2 was infected with S. mansoni cercariae and group 3 was orally infected with T. spiralis larvae, then 28 days later, this group was infected with S. mansoni cercariae. All groups were sacrificed at the end of the 8th week post infection with S. mansoni to evaluate the effect of pre-infection with T. spiralis on S. mansoni induced liver fibrosis was evaluated parasitologically (worm burden and egg count in tissues), biochemically (levels of alanine aminotransferase and aspartate aminotransferase), histopathologically (H&E and MT staining, and immunohistochemical staining for the expression of α-SMA, IL-6, IL-1β, IL-17, IL-23, TNF-α, and TGF-β).ResultsThe results in the present study demonstrated marked protective effect of T. spiralis against S. mansoni induced liver pathology. We demonstrated that pre-infection with T. spirais caused marked reduction in the number of S. mansoni adult worms (3.17 ± 0.98 vs. 18 ± 2.16, P = 0.114) and egg count in both the intestine (207.2 ± 64.3 vs. 8,619.43 ± 727.52, P = 0.009) and liver tissues (279 ± 87.2 vs. 7,916.86 ± 771.34; P = 0.014). Consistently, we found significant reductions in both number (3.4 ± 1.1 vs. 11.8.3 ± 1.22; P = 0.007) and size (84 ± 11 vs. 294.3 ± 16.22; P = 0.001) of the hepatic granulomas in mice pre-infected with T. spiralis larvae compared to those infected with only S. mansoni. Furthermore, pre- infection with T. spiralis markedly reduced S. mansoni- induced hepatic fibrosis, as evidenced by decreased collagen deposition, low expression of α-SMA, and significantly reduced levels of IL-17, IL-1B, IL-6, TGF-B, IL-23, and TNF-α compared to mice infected with S. mansoni only.ConclusionsOur data show that pre-infection with T. spiralis effectively protected mice from severe schistosomiasis and liver fibrosis. We believe that our findings support the potential utility of helminths for the preventing and ameliorating severe pathological alterations induced by schistosomiasis.

Objectives: Alveolar echinococcosis is caused by Echinococcus multilocularis, a parasite of zoo¬notic significance with a wide range of intermediate and final hosts, and the parasite survives suc¬cessfully in diversified conditions. Plentiful studies have been done to study the genetic structure of the population of the parasite and the level of intimate kinship using mitochondrial (mt) DNA. The present study was conducted to investigate the population structure, genetic variation, and phylogenetic relationship of various isolates of E. multiocularis submitted to GenBank worldwide. Sequences of mt genes (mt-cytochrome c oxidase (cox1), mt-NADH dehydrogenase (nad1)) of E. multilocularis were analyzed to achieve the set goals. Materials and Methods: A total of 275 and 124 gene sequences of mt-cox1 and mt-nad1 belong¬ing to E. multilocularis, respectively, were retrieved from the National Center for Biotechnology Information GenBank. The retrieved sequences were subjected to alignment with respective reference sequences using MEGA software. The PopArt software was used to establish medi¬an-joining networks, while DnaSp was used to calculate neutrality and diversity indices. MrBayes software was used to investigate the phylogenetic association between haplotypes based on Bayesian phylogeny. Results: Approximately 13 and 20 distinctive haplotypes of nad1 and cox1 genes, respectively, were observed in the present study. In both of the mt genes, diversity indices indicated low haplo¬type (mt-cox1 = 0.140; mt-nad1 = 0.374) and nucleotide (mt-cox1 = 0.00111; mt-nad1 = 0.00287) diversities. The values of Tajima's D and Fu Fs for a population of both of the genes under study were found to be negative. Conclusion: This study is a maiden attempt to provide insights into the population structure and genetic variation of E. multilocularis on a global scale. However, it is suggested that to better understand the population structure and genetic diversity of E. multilocularis, more geographical locations and amplifications of full-length gene sequences should be considered, which could be helpful in widening the insights into the genetic diversity of E. multilocularis. [J Adv Vet Anim Res 2024; 11(2.000): 264-274]

Learning-oriented assessment (LoA) has emerged as a learning approach to improving student learning. The integration of LoA into vocational education creates a powerful framework that not only assesses students’ competencies effectively but also enhances their learning experience by making it more relevant, practical, and aligned with industry needs. This article fills a crucial research gap in learning assessment and offers valuable insights for practitioners and researchers to enhance learning approaches. This research uses the systematic literature network analysis method. It is a combination of a systematic literature review using the PRISMA protocol and bibliometric analysis using the VosViewer and Biblioshiny software. This research uses the Scopus database from 2018 to September 2023, totalling 378 papers. The network visualization analysis shows several keywords of LoA, including learning, humans, teaching, assessment, artificial intelligence, and digital technology. LoA can be implemented into vocational education covering the domains of skills and procedural knowledge. Further research on LoA can be linked to measuring students’ critical thinking, learning outcomes, and other relevant abilities. LoA can interact through blended, online, collaborative, work practice, project-based and digital technology-based learning. The results can serve as a guide for researchers in the LoA field to select and find future research topics.

Majed H Wakid,1,2 Muslimah N Alsulami,3 Mohamed Farid,4 Walaa A El Kholy5 1Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, 21589, Saudi Arabia; 2Special Infectious Agents Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia; 3Department of Biology, College of Science, University of Jeddah, Jeddah, Saudi Arabia; 4Sciences Academy of Experimental Researches, Special Scientific Foundation, Mansoura, Egypt; 5Department of Parasitology, Faculty of Medicine for Girls, Al-Azhar University, Cairo, EgyptCorrespondence: Majed H Wakid, Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, P. O. Box 80324, Jeddah, 21589, Saudi Arabia, Tel +9662-6952000 ext. 25264, Email mwakid@kau.edu.saBackground: Toxoplasmosis is a parasitic disease caused by Toxoplasma gondii that infects humans and many types of mammals and birds.Objective: To investigate the effect of selenium nanoparticles (SeNPs) and Phoenix dactylifera (Pd) extracts loaded on SeNPs as a new agent to combat chronic T. gondii infections in murine model as an alternative method to standard Spiramycin drug therapy.Methods: A total of 64 female mice were randomly divided into eight groups: GI: Normal control, GII: Positive control, GIII: infected and treated with Spiramycin, GIV: infected and treated with SeNPs, GV: infected and treated with aqueous extract of Pd, GVI: infected and treated with methanolic extract of Pd, GVII: infected and treated with aqueous extract of Pd loaded on SeNPs, GVIII: infected and treated with methanolic extract of Pd loaded on SeNPs. Date palm (P. dactylifera) fruits were identified and collected from the farms of Saudi Arabia. Preparation and characterization of SeNPs were done. The parasitological, histopathological examinations and biochemical changes were evaluated in all groups.Results: Parasitological results showed significant differences in GVII in comparison to GII while GVIII showed significant differences in comparison to GII and GIII. The histopathological section of the cerebral cortex showed obvious alterations in the infected compared with untreated control groups. Aqueous and methanolic extracts of P. dactylifera loaded on SeNPs treatment showed improvement that indicated by few perivascular cuffing with few inflammatory cell infiltrations. Few granule cells with mild intracellular vacuolation and edema few deformed neurons with deep pyknotic nuclei. Microglia cells expression of Iba-1 and inflammatory cytokines (IL-4, IL-10 and INF-γ) in serum of all groups was higher in GII and lowest in GVIII followed by GVII.Conclusion: SeNPs and P. dactylifera extracts loaded on SeNPs could be a potent agent to combat T. gondii infections.Plain Language Summary: Toxoplasma gondii is a parasite, causing toxoplasmosis, has a sexual life cycle, which takes place in the small intestine of cats, and an asexual cycle that takes place in warmed animals and humans. It is a neurotropic obligate intracellular parasite. The pyrimethamine and sulfadiazine are the preferred treatment for toxoplasmosis. Recent studies have indicated adverse side effects such as osteoporosis and teratogenic effects, mostly in immunocompromised individuals. The authors hypothesized there is an urgent need to discover new natural products or biosynthetic agents with fewer side effects and higher efficacy. Dates are rich in dietary fiber, vitamins, fatty acids, and amino acids and play a key role in the neutralization of free radicals, which inhibits the onset and progression of several disorders. As selenium is essential for both innate and adaptive immune responses against bacterial and parasite infections. Moreover, nanoparticles have a large surface-volume ratio and numerous biological benefits such as their convenient entry into the cell compared to other particles. So, the authors reported that selenium nanoparticles and palm dates extracts loaded on them could be a potent agent to combat Toxoplasma infections and verifications were performed in the study.Keywords: Phoenix dactylifera, selenium, nanoparticles, Toxoplasma gondii, spiramycin

BackgroundCryptosporidiosis is an opportunistic parasitic disease widely distributed worldwide. Although Cryptosporidium sp. causes asymptomatic infection in healthy people, it may lead to severe illness in immunocompromised individuals. Limited effective therapeutic alternatives are available against cryptosporidiosis in this category of patients. So, there is an urgent need for therapeutic alternatives for cryptosporidiosis. Recently, the potential uses of Eugenol (EUG) have been considered a promising novel treatment for bacterial and parasitic infections. Consequently, it is suggested to investigate the effect of EUG as an option for the treatment of cryptosporidiosis.Materials and methodsThe in silico bioinformatics analysis was used to predict and determine the binding affinities and intermolecular interactions of EUG and Nitazoxanide (NTZ) toward several Cryptosporidium parvum (C. parvum) lowa II target proteins. For animal study, five groups of immunosuppressed Swiss albino mice (10 mice each) were used. Group I was left uninfected (control), and four groups were infected with 1,000 oocysts of Cryptosporidium sp. The first infected group was left untreated. The remaining three infected groups received NTZ, EUG, and EUG + NTZ, respectively, on the 6th day post-infection (dpi). All mice were sacrificed 30 dpi. The efficacy of the used formulas was assessed by counting the number of C. parvum oocysts excreted in stool of infected mice, histopathological examination of the ileum and liver tissues and determination of the expression of iNOS in the ileum of mice in different animal groups.Resultstreatment with EUG resulted in a significant reduction in the number of oocysts secreted in stool when compared to infected untreated mice. In addition, oocyst excretion was significantly reduced in mice received a combination therapy of EUG and NTZ when compared with those received NTZ alone. EUG succeeded in reverting the histopathological alterations induced by Cryptosporidium infection either alone or in combination with NTZ. Moreover, mice received EUG showed marked reduction of the expression of iNOS in ileal tissues.ConclusionBased on the results, the present study signified a basis for utilizing EUG as an affordable, safe, and alternative therapy combined with NTZ in the management of cryptosporidiosis.

Monieziasis is a parasite-borne production-limiting disease of livestock. Moniezia expansa is the most important species having cosmopolitan distribution. Despite of numerous prevalence reports, very little information is available about the evolutionary biology and population genetics of M. expansa. To close this research gap, this study was undertaken to recognize and inspect the genetic variation of M. expansa populations around the world using the cox1 and nad1 genes and deduce phylogenetic relationships with M. expansa populations. The cox1 and nad1 gene sequences were downloaded from the NCBI GenBank database. Followed by sequence alignment, median-joining networks were constructed using PopArt software. Diversity and neutrality indices were computed through DnaSp software while MEGA software was used to draw the maximum-likelihood phylogenetic tree. Thirty-two cox1 sequences, from five different countries, and 9 nad1 sequences from three different countries, were among the sequences used in this study. The cox1 and nad1 gene sequences had mutations in 97 and 36 different places, respectively. Twenty and 7 unique haplotypes were discovered for the cox1 and nad1 gene sequences, respectively. Comparable haplotype diversities were observed for both the genes under study (cox1 = 0.950; nad1 = 0.944). Negative Tajima's D and Fu Fs were found for the cox1 gene while these indices were positive for the nad1 gene. Phylogenetic analysis also showed the existence of unique haplotypes for both the cox1 and nad1 genes. The results of this study indicate that there is the existence of a huge genetic diversity in M. expansa isolates. For future studies, it is recommended that longer gene sequences should be used to describe genetic variation among M. expansa isolates as the length of the gene under study affects the genetic variation. Moreover, additional mitochondrial markers should also be investigated because the assertive strength of a group of gene targets is superior to defining genetic diversity.

Muslimah N Alsulami,1 Khalil Mohamed,2 Majed H Wakid,3,4 Rewaida Abdel-Gaber,5 Ashraf G Timsah,6,7 Wafa Abdullah I Al-Megrin,8 Adil Khan,9 Walaa A Elkholy,10 Khaled AA Abdelaal,11 Hatem A Elshabrawy,12 Asmaa M El-Kady13 1Department of Biology, College of Science, University of Jeddah, Jeddah, Saudi Arabia; 2Department of Epidemiology, Faculty of Public Health and Health Informatics, Umm Al-Qura University, Mecca, Saudi Arabia; 3Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, 21589, Saudi Arabia; 4Special Infectious Agents Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia; 5Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia; 6Department of Microbiology, Faculty of Medicine, Al-Baha University, Al Baha, Saudi Arabia; 7Department of Medical Parasitology, Faculty of Medicine Al-Azhar University, New Damietta City, Egypt; 8Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, Riyadh, Saudi Arabia; 9Department of Zoology, Bacha Khan University, Charsadda, Pakistan; 10Department of Medical Parasitology, Faculty of Medicine, Al-Azhar University, Cairo, Egypt; 11EPCRS Excellence Center, Plant Pathology and Biotechnology Lab, Faculty of Agriculture, Kafrelsheikh University, Kafr El Sheikh, 33516, Egypt; 12Department of Molecular and Cellular Biology, College of Osteopathic Medicine, Sam Houston State University, Conroe, TX, 77304, USA; 13Department of Medical Parasitology, Faculty of Medicine, South Valley University, Qena, EgyptCorrespondence: Hatem A Elshabrawy; Khaled AA Abdelaal, Tel +201283557774, Fax +20473109524, Email hatem.elshabrawy@shsu.edu; khaled.elhaies@gmail.comIntroduction: World Health Organization (WHO) considers Fascioliasis as a neglected tropical disease that requires global efforts for disease control. Data from the genetic characterization of Fasciola population shed light on the spread of infections among animals which could help in the development of effective parasite control. The aim of the present work was to genetically characterize Fasciola adult worms isolated from sheep in Saudi Arabia by sequence analysis of ITS-1 region.Methods: A total of 12,653 slaughtered sheep in Jeddah city, Saudi Arabia were examined for the presence of Fasciola spp. adult worms. The ITS-1 region of all parasites was amplified and sequenced.Results: Overall, 12 variants DNA sequences were obtained. The variance of isolates ranged from 0.00771 to 0.34405. BLAST search showed that all obtained sequences were Fasciola hepatica and had > 99.3% similarity with F. hepatica isolates from Spain and USA (from different hosts other than sheep). Phylogenetic analysis showed that Fasciola isolates were closely related to isolates from different countries.Discussion: The current study showed that F. hepatica was the only spp. isolated from sheep in Jeddah. Further studies from different localities in Saudi Arabia are needed to help in the development of disease control.Keywords: genetic diversity, characterization, Fasciola hepatica, parasitic diseases, sheep

The green-lipped mussel Perna viridis’ sensitive nature and characteristic as a benthos organism that filters the sediment in its environment make it one of the possible bioindicators for pollution in the aquatic ecosystem. The present study aimed to determine the percentages of total shell deformities in comparison to the past data in the coastal waters of Peninsular Malaysia. It was found that several types of discontinuous, continuous, and unexplained shell abnormalities contributed to the overall range of shell deformities of 15.8–87.5%, which was greater in comparison to that (0.0–36.8%). The present study showed that the highest overall proportion of shell abnormalities occurred in Teluk Jawa, whereas the lowest percentages were found in Kampung (Kg.) Pasir Puteh. The regulative mechanisms at the well-known polluted sites at Kg. Pasir Puteh could be the explanation. Further research should be conducted to determine the degree of heavy metal that may be the source of these malformations in the mussel shells.

Mycobacterium bovis, the causative agent of bovine tuberculosis (BTB), is one of the most significant endemic diseases confronting government, veterinary professionals, and farming industry worldwide nowadays. M. bovis has not only a negative impact on bovine health and economy, but also poses a threat to public health as a zoonotic disease that could be transmitted from animal to human. Although, bacillus Calmette-Guérin (BCG) vaccine of M. bovis has been extensively used in many animals, only few studies had reported its side effects in these animals. In this study, the systemic pathological lesions and immunoglobulin levels associated with intranasal (IN) and subcutaneous (SC) injection of BCG vaccine in Swiss male mice have been evaluated. The results revealed an elevation in IgM and IgA levels in both routes (nebulization, subcutaneous injection) while there was a dramatic increase in IgG levels in subcutaneously injected mice. Aerosolization of BCG vaccine using a nebulizer resulted in severe pulmonary lesions with numerous megakaryocytes in the spleens of mice. On the other hand, SC injection had mild effect on pulmonary tissues and induced moderate extramedullary hematopoiesis in the hepatic tissues of mice. In conclusion, inadvertent vaccination of BCG in Swiss mice, triggered adverse tissue reaction and remarkable increase in Ig level. The severity of tissue lesions corresponded to the injection route in mice.

Background Diversity in clinical signs and symptoms are associated with soil transmitted diseases (STD), which are spread to humans by intestinal worms and transmitted in a variety of ways. There is a need for the present study, which aimed to investigate the prevalence of intestinal parasites and to compare between the common detection techniques for soil-transmitted helminths (STHs) among newly arrived expatriate labors in Jeddah, Saudi Arabia. Methods A total of 188 stool samples were analyzed by macroscopic examination, and microscopic examination using direct iodine smear and the formal ether sedimentation technique. Trichrome and modified Kinyoun’s stains were used to confirm the morphology of any detected protozoa stages and oocyst of Cryptosporidium, respectively. A chromatographic immunoassay kit was used for Entamoeba histolytica, Giardia lamblia and Cryptosporidium. In addition, real-time PCR was employed only to identify various STHs. Results Out of 188, several types of parasites were detected in 35 samples (18.62%), of which some with multiple infections. Nine samples (4.79%) were positive for Entamoeba coli, seven samples (3.72%) for Trichuris trichiura, six samples (3.19%) for Necator americanus, four samples (2.13%) for Strongyloides stercoralis, four samples (2.13%) for Ascaris lumbricoides, four samples (2.13%) for E. histolytica, three samples (1.60%) for Blastocystis hominis and two samples (1.06%) for Ancylostoma duodenale. In comparison between laboratory techniques for STHs, real-time PCR was able to detect the DNA of 19 samples (10.1%) followed by Ritchie sedimentation technique (18, 9.6%), and direct smear (7, 3.7%) (p > 0.05). Conclusion The high rate of newly arrived foreign workers infected with intestinal parasites could lead to a risk to society. Continuous and regular surveys are needed to deal with the occurrence of intestinal parasitic infections including STHs. To improve the identification of these infections, we recommend a supporting infrastructure for the application of concentration methods and molecular assays.

The neurovascular unit, comprised of vascular cell types that collectively regulate cerebral blood flow to meet the needs of coupled neurons, is paramount for the proper function of the central nervous system. The neurovascular unit gatekeeps blood-brain barrier properties, which experiences impairment in several central nervous system diseases associated with neuroinflammation and contributes to pathogenesis. To better understand function and dysfunction at the neurovascular unit and how it may confer inflammatory processes within the brain, isolation and characterization of the neurovascular unit is needed. Here, we describe a singular, standardized protocol to enrich and isolate microvessels from archived snap-frozen human and frozen mouse cerebral cortex using mechanical homogenization and centrifugation-separation that preserves the structural integrity and multicellular composition of microvessel fragments. For the first time, microvessels are isolated from postmortem ventromedial prefrontal cortex tissue and are comprehensively investigated as a structural unit using both RNA sequencing and Liquid Chromatography with tandem mass spectrometry (LC-MS/MS). Both the transcriptome and proteome are obtained and compared, demonstrating that the isolated brain microvessel is a robust model for the NVU and can be used to generate highly informative datasets in both physiological and disease contexts.

Abstract Hepatic fascioliasis is an important parasitic disease responsible for morbidity and mortality in many domestic ruminants, especially sheep, goats, and cattle, due to Fasciola (F.) hepatica and F. gigantica. This study aimed to determine the prevalence of fascioliasis in sheep slaughtered in Jeddah, Saudi Arabia, and to describe the morphological and histopathological changes in the liver. A total of 109,253 sheep slaughtered between July 2017 and July 2018 were screened to assess the prevalence of fascioliasis. The livers were grossly investigated for Fasciola infection and morphological changes. Tissue samples were collected for proper histopathological examinations. Livers of local and imported sheep represented infection rates of 0.67% and 2.12%, respectively, and the highest infection rate was in the spring season. Macroscopically, the affected liver showed hepatomegaly, thickened capsule and discoloration with necrosis, fibrosis, dilation of the bile duct, engorgement of the gallbladder and enlargement of the portal lymph nodes. Microscopic examination showed fibrotic thickening, calcification and hyperplasia of the bile ducts filled with debris, as well as massive hemorrhagic foci. Histopathological examinations of the infected liver showed a central vein region with disturbed parenchyma cells, focal lymphocytic infiltration, elongated endothelial cells, blood sinusoids that showed enlarged Kupffer cells, patches of lysed or necrotic hepatocytes, eosinophil infiltration, lymphocytes and proliferating fibroblast, thickening of hepatic artery and arteriolar walls. We concluded that fascioliasis among sheep slaughtered in Jeddah is not uncommon. The identified histopathological changes in the liver of infected sheep reflect tissue damage, which can lead to significant economic losses for the animals.

Abstract Background Livelihood activities and human movements participate in the epidemiology of vector-borne diseases and influence malaria risk in elimination settings. In Saudi Arabia, where malaria transmission intensity varies geographically, it is vital to understand the components driving transmission within specific areas. In addition, shared social, behavioural, and occupational characteristics within communities may provoke the risk of malaria infection. This study aims to understand the relationship between human mobility, livelihood activities, and the risk of malaria infection in the border region of Jazan to facilitate further strategic malaria interventions. In addition, the study will complement and reinforce the existing efforts to eliminate malaria on the Saudi and Yemen border by providing a deeper understanding of human movement and livelihood activities. Methods An unmatched case–control study was conducted. A total of 261 participants were recruited for the study, including 81 cases of confirmed malaria through rapid diagnostic tests (RDTs) and microscopy and 180 controls in the Baish Governorate in Jazan Provinces, Saudi Arabia. Individuals who received malaria tests were interviewed regarding their livelihood activities and recent movement (travel history). A questionnaire was administered, and the data was captured electronically. STATA software version 16 was used to analyse the data. Bivariate and multivariate analyses were conducted to determine if engaging in agricultural activities such as farming and animal husbandry, recent travel history outside of the home village within the last 30 days and participating in spiritual gatherings were related to malaria infection status. Results A logistical regression model was used to investigate components associated with malaria infection. After adjusting several confounding factors, individuals who reported travelling away from their home village in the last 30 days OR 11.5 (95% CI 4.43–29.9), and those who attended a seasonal night spiritual gathering OR 3.04 (95% CI 1.10–8.42), involved in animal husbandry OR 2.52 (95% CI 1.10–5.82), and identified as male OR 4.57 (95% CI 1.43–14.7), were more likely to test positive for malaria infection. Conclusion Human movement and livelihood activities, especially at nighttime, should be considered malaria risk factors in malaria elimination settings, mainly when the targeted area is limited to a confined borderland area.

Head lice (Pediculus humanus capitis) are a major global concern, and there is growing evidence of an increase in head lice prevalence among Saudi schoolchildren. The purpose of this study is to investigate the prevalence of an insecticidal resistance mutation in head lice collected from schoolchildren. A polymerase chain reaction (PCR) was used to amplify a segment of the voltage-gated sodium channel gene subunit to assess the prevalence and distribution of the kdr T917I mutation in head lice. Subsequently, the restriction fragment length polymorphism (RFLP) patterns revealed two genotypic forms: homozygous-susceptible (SS) and homozygous-resistant (RR). The results showed that 17 (37.80%) of the 45 samples were SS, whereas 28 (62.2%) were RR and T917I and L920F point mutations were found in the nucleotide and amino acid sequences of RR. Compared to other nations, the frequency of permethrin resistance mutation in the head louse population in Saudi Arabia was low. This study provides the first evidence of permethrin resistance mutation in human head lice in Saudi Arabia. The findings of this study will highlight the rising incidence of the kdr mutation in head lice in Saudi Arabia.

Muslimah N Alsulami,1 Majed H Wakid,2 Mohammed Al-matary,3 Rewaida Abdel-Gaber,4 Wafa Abdullah I Al-Megrin,5 Areej O Bakhraibah,1 Abdullah D Alanazi,6 Hatem A Elshabrawy,7 Asmaa M El-Kady8 1Department of Biology, College of Science, University of Jeddah, Jeddah, 21493, Saudi Arabia; 2Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, 21589, Saudi Arabia; 3Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah, 21589, Saudi Arabia; 4Department of Zoology, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia; 5Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, Riyadh, 11671, Saudi Arabia; 6Department of Biological Sciences, Faculty of Science and Humanities, Shaqra University, Ad-Dawadimi, 11911, Saudi Arabia; 7Department of Molecular and Cellular Biology, College of Osteopathic Medicine, Sam Houston State University, Conroe, TX, 77304, USA; 8Department of Medical Parasitology, Faculty of Medicine, South Valley University, Qena, 83523, EgyptCorrespondence: Asmaa M El-Kady; Hatem A Elshabrawy, Email Asmaa.elkady@med.svu.edu.eg; hatem.elshabrawy@shsu.eduBackground: In Saudi Arabia, more than US$ 0.2 million annual losses are caused by liver condemnations due to fascioliasis. Data obtained from the genetic characterization of Fasciola population sheds light on parasite transmission which could eventually help in development of effective parasite control measures. So, the aim of this study was to investigate the genetic diversity of Fasciola spp. isolated from cattle in Saudi Arabia by sequence analyses of COI gene.Materials and Methods: A total of 325 cows slaughtered at the central municipal abattoir in Jeddah city, Jeddah Province, Saudi Arabia were examined for fascioliasis in the period from 1st of June to 1st of July 2020. DNA was extracted from adult Fasciola worms and used for PCR and DNA sequence using a primer pair targeting COI gene. Analysis of the obtained sequences was done using BLAST search and phylogenetic analysis.Results: Bovine fascioliasis was diagnosed in 18 out of 325 cattle (5.5%). Forty-eight flukes were extracted from infected animals and DNA was successfully amplified from all flukes. Overall 12 different DNA sequences were obtained. BLAST search showed that all obtained sequences were F. hepatica and had > 97% similarity with F. hepatica isolates from Tanzania, Europe and Iran. Phylogenetic analysis of the obtained sequences showed that Fasciola isolates from the current study were clustered in one subclade closely related to isolates from North and South Africa and Italy.Conclusion: Reports on the molecular characterization of Fasciola spp. in Saudi Arabia are limited. In the current study, our findings showed that F. hepatica was the only Fasciola species parasitizing cattle in Jeddah city, Saudi Arabia. Further studies using a large number of samples from different localities in Saudi Arabia are needed to provide data that will help the development of control measures against fascioliasis.Keywords: fascioliasis, cattle, PCR, COI, Saudi Arabia

BackgroundAlthough, approximately 30% of the world's population is estimated to be infected with Toxoplasma gondii (T. gondii) with serious manifestations in immunocompromised patients and pregnant females, the available treatment options for toxoplasmosis are limited with serious side effects. Therefore, it is of great importance to identify novel potent, well tolerated candidates for treatment of toxoplasmosis. The present study aimed to evaluate the effect of Zinc oxide nanoparticles (ZnO NPs) synthesized using Zingiber officinale against acute toxoplasmosis in experimentally infected mice.MethodsThe ethanolic extract of ginger was used to prepare ZnO NPs. The produced ZnO NPs were characterized in terms of structure and morphology using Fourier Transformed Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), UV- spectroscopy and scanning electron microscopy (SEM). The prepared formula was used in treatment of T. gondii RH virulent strain. Forty animals were divided into four groups, with ten mice per group. The first group was the uninfected, control group. The second group was infected but untreated. The third and the fourth groups received ZnO NPs and Spiramycin orally in a dose of 10 mg/kg and 200 mg/kg/day respectively. The effect of the used formulas on the animals survival rate, parasite burden, liver enzymes -including Alanine transaminase (ALT) and aspartate transaminase (AST)-, nitric oxide (NO) and Catalase antioxidant enzyme (CAT) activity was measured. Moreover, the effect of treatment on histopathological alterations associated with toxoplasmosis was examined.ResultsMice treated with ZnO NPs showed the longest survival time with significant reduction in the parasite load in the livers and peritoneal fluids of the same group. Moreover, ZnO NPs treatment was associated with a significant reduction in the level of liver enzymes (ALT, AST) and NO and a significant increase in the antioxidant activity of CAT enzyme. SEM examination of tachyzoites from the peritoneal fluid showed marked distortion of T. gondii tachyzoites isolated from mice treated with ZnO NPs in comparison to untreated group. T. gondii induced histopathological alterations in the liver and brain were reversed by ZnO NPs treatment with restoration of normal tissue morphology.ConclusionThe produced formula showed a good therapeutic potential in treatment of murine toxoplasmosis as demonstrated by prolonged survival rate, reduced parasite burden, improved T. gondii associated liver injury and histopathological alterations. Thus, we assume that the protective effect observed in the current research is attributed to the antioxidant capability of NPs. Based on the results obtained from the current work, we suggest greenly produced ZnO NPs as a chemotherapeutic agent with good therapeutic potential and high levels of safety in the treatment of toxoplasmosis.

Abstract Ganges River dolphins echolocate, but this mechanism is inadequate for poor sonar-echoing objects such as the monofilament gillnets, causing considerable net entanglement related mortalities. Net entanglement related deaths are one of the major causes of cetacean population decline around the world. Experiments were carried out to understand the use of pingers—an acoustic deterrent, in aiding the deterrence of dolphins from fishing nets. Based on the dolphin clicks recorded, in an experimental setup spanning 36 days, a 90% deterrence was found; 22.87 ± 0.71 SE dolphin detection positive minutes per hour near non-pingered nets versus 2.20 ± 0.33 SE per hour near pingered net. Within 30 m radii of nets, visual encounters of non-calf reduced by 52% and calf by 9%, in the presence of pingers. No evidence of habituation to pingers, habitat avoidance in dolphins after pinger removal or a change in fish catch in nets because of pingers was found during the study. While the effectiveness of pingers on calves and fish catch needs further experimentation, the use of pingers to minimize net entanglement mortalities in the Ganges River dolphins seems to be the most promising solution currently available. These results have critical implications for the conservation of other species of river dolphins around the world.

Asmaa M El-Kady,1 Heba A Osman,2 Mohamed Farouk Alemam,3 Dina Marghani,4 Mohammed A Shanawaz,5 Majed H Wakid,6,7 Wafa Abdullah I Al-Megrin,8 Hatem A Elshabrawy,9 Osama H Abdella,1 Khaled S Allemailem,10 Ahmad Almatroudi,10 Mostafa I EL-Amir11 1Department of Medical Parasitology, Faculty of Medicine, South Valley University, Qena, Egypt; 2Department of Gastroenterology and Tropical Medicine, Faculty of Medicine, South Valley University, Qena, Egypt; 3Department of Clinical Pathology, Faculty of Medicine, South Valley University, Qena, Egypt; 4Clinical Laboratory Science Department, Faculty of Applied Medical Science, Taibah University, Medina, Kingdom of Saudi Arabia; 5Department of Public Health, Applied Medical Sciences College, Albaha University, Albaha, Saudi Arabia; 6Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia, Jeddah, 21589, Saudi Arabia; 7Special Infectious Agent Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia; 8Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, Riyadh, 11671, Saudi Arabia; 9Department of Molecular and Cellular Biology, College of Osteopathic Medicine, Sam Houston State University, Conroe, TX, 77304, USA; 10Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah, 51452, Saudi Arabia; 11Department of Medical Microbiology and Immunology, Faculty of Medicine, South Valley University, Qena, EgyptCorrespondence: Asmaa M El-Kady; Hatem A Elshabrawy, Email asmaa.elkady@med.svu.edu.eg; hatem.elshabrawy@shsu.eduIntroduction: In recent decades, the rate of infection with dengue virus (DENV) has risen significantly, now affecting nearly 400 million individuals annually. Dengue fever among humans is caused via specific mosquito vectors bites. Sporadic cases have been reported in Egypt. The goal of this study was to identify the serotype of the DENV outbreak in both human and mosquito vector along the coast of the Red Sea, Upper Egypt, in 2017. Identification of the serotype of the virus may help identify its source and assist in applying epidemiological and control measures.Materials and Methods: The current study was carried out in El Quseir City, Red Sea Governorate, Upper Egypt, on 144 patients complaining of symptoms indicative of dengue fever at the time of the 2017 Egypt outbreak. Human blood samples and the mosquito reservoirs were identified as having dengue virus infection serologically and molecularly.Results: Overall, 97 (67.4%) patients were positive for dengue virus IgM antibodies. Molecular examination of the human samples and pools of mosquitoes revealed that DENV-2 virus was the serotype responsible for the outbreak. Only one pool of female mosquitoes containing Aedes aegypti was infected with dengue fever virus (DENV-2).Conclusion: This was the first serotyping of the DENV responsible for dengue virus outbreak in Egypt in 2017. Determining the serotype of dengue virus can help to avoid and monitor outbreaks. The serotype identified in this study was DENV-2, while DENV-1 was the serotype found in the previous outbreak in 2015 in the province of Assiut. This study thus raises concerns that a new dengue serotype could have been introduced into Egypt. It is necessary for a comprehensive risk assessment to be carried out in the country, including an entomological survey, to assess the presence and potential geographical expansion of mosquito vectors there.Keywords: dengue fever, Upper Egypt, serotyping, human, mosquito, multiplex PCR

Majed H Wakid,1,2 Waad T Aldahhasi,3 Muslimah N Alsulami,3 Asmaa M El-Kady,4 Hatem A Elshabrawy5 1Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, 21589, Saudi Arabia; 2Special Infectious Agents Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, 21589, Saudi Arabia; 3Department of Biology, College of Science, University of Jeddah, Jeddah, 21493, Saudi Arabia; 4Department of Medical Parasitology, Faculty of Medicine, South Valley University, Qena, 83523, Egypt; 5Department of Molecular and Cellular Biology, College of Osteopathic Medicine, Sam Houston State University, Conroe, TX, 77304, USACorrespondence: Asmaa M El-Kady; Hatem A Elshabrawy, Email asmaa.elkady@med.svu.edu.eg; hatem.elshabrawy@shsu.eduBackground: Blastocystis species (sp.) are gastrointestinal protozoan parasites with high prevalence rates worldwide. Blastocystis sp. show extensive genetic diversity with 17 different subtypes (STs) described to date. A few studies have investigated the prevalence and STs of Blastocystis sp. in Makkah, Saudi Arabia. Therefore, we aimed in this study to identify and characterize subtypes of Blastocystis sp. in the City of Makkah, Saudi Arabia.Methods: Stool samples were collected from 140 patients who presented to King Abdulaziz Hospital, Hera General Hospital and Modern Medical Center in Saudi Arabia. Different microscopic examination methods of patients’ stools and molecular analyses (using primers targeting SSU rRNA gene) were performed to identify and characterize STs of Blastocystis sp.Results: Our microscopic examination of stool samples showed that 96/140 patients (68.6%) had Blastocystis sp. infection. Clinical examination of infected patients revealed that 81 patients were symptomatic, whereas 15 were asymptomatic. Next, we isolated DNA from Blastocystis sp.-positive stool samples followed by PCR amplification of small-subunit ribosomal RNA (SSU rRNA) gene and sequence analysis. Our sequence analysis showed that subtype 3 (ST3) was the most prevalent (53.13%) followed by subtype 1 (ST1) (45.83%), whereas subtype 2 (ST2) was the least prevalent (1.04%). Moreover, our results showed that all three STs resulted in more symptomatic than asymptomatic cases. Finally, we identified novel haplotypes which comprised of 8 ST3, 6 ST1, and one ST2 haplotypes.Conclusion: Our identification of several haplotypes in patients’ stools confirms the genetic diversity of Blastocystis sp. and may explain the reported low host specificity and differential pathogenicity of Blastocystis sp. We believe that additional molecular epidemiological and genomic studies are needed to understand the prevalence and pathogenicity of different subtypes in humans and animal hosts.Keywords: Blastocystis sp., genotyping, subtype, haplotype, ST1, ST2, ST3, Saudi Arabia

Background: Schistosomiasis affects approximately 250 million people worldwide, with 200,000 deaths annually. It has been documented that the granulomatous response to Schistosoma mansoni (S. mansoni) oviposition is the root cause of progressive liver fibrosis in chronic infection, in 20% of the patients, and can lead to liver cirrhosis and/or liver cancer. The influence of helminths coinfection on schistosomiasis-induced liver pathological alterations remains poorly understood. Therefore, in this study, we investigated the effect of Trichinella spiralis (T. spiralis) infection on S. mansoni-induced hepatic fibrosis. Materials and methods: Thirty adult male Balb-c mice were divided into three groups. Group 1 was left uninfected; group 2 was infected with S. mansoni cercariae and group 3 was orally infected with T. spiralis larvae, then 28 days later, this group was infected with S. mansoni cercariae. All groups were sacrificed at the end of the 8th week post infection with S. mansoni to evaluate the effect of pre-infection with T. spiralis on S. mansoni induced liver fibrosis was evaluated parasitologically (worm burden and egg count in tissues), biochemically (levels of alanine aminotransferase and aspartate aminotransferase), histopathologically (H&E and MT staining, and immunohistochemical staining for the expression of a-SMA, IL-6, IL-1b, IL-17, IL-23, TNF-a, and TGF-b). Results: The results in the present study demonstrated marked protective effect of T. spiralis against S. mansoni induced liver pathology. We demonstrated that pre-infection with T. spirais caused marked reduction in the number of S. mansoni adult worms (3.17 ± 0.98 vs. 18 ± 2.16, P = 0.114) and egg count in both the intestine (207.2 ± 64.3 vs. 8,619.43 ± 727.52, P = 0.009) and liver tissues (279 ± 87.2 vs. 7,916.86 ± 771.34; P = 0.014). Consistently, we found significant reductions in both number (3.4 ± 1.1 vs. 11.8.3 ± 1.22; P = 0.007) and size (84 ± 11 vs. 294.3 ± 16.22; P = 0.001) of the hepatic granulomas inmice pre-infected with T. spiralis larvae compared to those infected with only S. mansoni. Furthermore, pre-infection with T. spiralis markedly reduced S. mansoni-induced hepatic fibrosis, as evidenced by decreased collagen deposition, low expression of a-SMA, and significantly reduced levels of IL-17, IL-1B, IL-6, TGF-B, IL-23, and TNF-a compared to mice infected with S. mansoni only. Conclusions: Our data show that pre-infection with T. spiralis effectively protected mice from severe schistosomiasis and liver fibrosis. We believe that our findings support the potential utility of helminths for the preventing and ameliorating severe pathological alterations induced by schistosomiasis. [ABSTRACT FROM AUTHOR]

Background This study aimed to evaluate the association between socio-demographic status, and hygienic habits among food handlers with intestinal parasitic infections. Methods It was a cross-sectional study in which 112 participants were recruited, from Belgarn province of Saudi Arabia. The descriptive analysis was used to evaluate demographic data and categorical variables. The association between sociodemographic characteristics and Relative Risk regression analysis was performed for each investigated factor. p-value of

BackgroundTrichinellosis is a helminthic disease caused by Trichinella spiralis via the ingestion of raw or undercooked meat of infected animals. Current estimates indicate that 11 million humans have trichinellosis, worldwide. The effective use of anti-trichinella medications is limited by side effects and resistance which highlight the critical need for safe and effective drugs, particularly those derived from medicinal plants. Therefore, in the present study, we aimed to evaluate the efficacy of the ethanolic extract of Artemisia annua (A. annua) in treatment of experimentally induced trichinellosis.Materials and methodsTrichinellosis was induced experimentally in male 6–8 weeks BALB/c mice. BALB/c mice were divided into four groups, 10 mice each. One group was left uninfected and untreated, whereas three groups were infected with T. spiralis. One infected group of mice was left untreated (negative control) while the remaining two infected groups received either 300 mg/kg of the ethanolic extract of A. annua or 50 mg/kg of albendazole (positive control). All treatments started from the third day post-infection (dpi) for 3 successive days. All animals were sacrificed on the 7th dpi for evaluation of treatment efficacy.ResultsOur findings showed that A. annua treatment reduced the T. spiralis adult-worm count in the intestine of infected animals. Moreover, treatment with A. annua restored the normal intestinal architecture, reduced edema, alleviated inflammation as demonstrated by reduced inflammatory infiltrate and expression of TGF-β in intestinal tissues of A. annua-treated animals compared to infected untreated animals.ConclusionsOur findings show that A. annua extract is effective in treating experimentally induced trichinellosis which highlight the therapeutic potential of A. annua for intestinal trichinellosis.

Background The study was conducted to observe the prevalence and type of infection caused by intestinal parasites and to compare the techniques that are available for the detection. Method A total of 112 stool samples were obtained from study participants, and the laboratory examinations were performed at Special Infectious Agents Unit, King Abdulaziz University, Jeddah. One hundred and twelve participants were included in this study. Result The color of positive specimens was mainly brown (86.4%). Stool consistency in infected cases was soft in (64%) samples. There was no statistically significant difference with the physical characteristics of the stool (P > 0.05). In total, 59 of the 112 participants were infected with intestinal parasites, representing 52.7%. Different intestinal protozoa parasites were identified in which Blastocystis hominis (86.4%) was highest. None of the intestinal helminths were detected. Out of the 59 infected cases, single infections were found in (62.7%) samples. The intestinal protozoan parasites in single infections were B. hominis (78.4%), Giardia lamblia (8.1%), and (2.7%) from each Entamoeba histolytica, Cryptosporidium parvum, Entamoeba coli, Endolimax nana, and Chilomastix mesnili. Microscopy, RDTs, and real-time PCR were used for detection and identification of G. lamblia, E. histolytica, and C. parvum. Conclusion The study reported a high rate of intestinal parasitic infections, mainly with B. hominis. There were no statistical differences in parasite detection between the three techniques in detection of the thirteen cases infected with the pathogenic protozoa.

Cryptosporidiosis is a serious parasitic diarrheal disease linked to the occurrence of colorectal cancer in immunocompromised patients. The FDA-approved drug nitazoxanide (NTZ) achieved a temporary effect, and relapses occur. Annona muricata leaf is widely used in traditional medicine to treat a wide range of disorders, including antiparasitic and anticancer effects. So, this study aimed to investigate Annona muricata leaf antiparasitic and anticancer properties compared to NTZ in Cryptosporidium parvum (C. parvum) acutely and chronically infected immunosuppressed mice. A molecular docking analysis was performed to evaluate the effectiveness of some biologically active compounds that represented the pharmacological properties of Annona muricata leaf-rich extract toward C. parvum lactate dehydrogenase compared to NTZ. For the in vivo study, eighty immunosuppressed albino mice were classified into four groups as follows: group I: infected and treated with A. muricata; group II: infected and treated with nitazoxanide; group III: infected and received no treatment; and group IV: were neither infected nor treated. Furthermore, half of the mice in groups I and II received the drugs on the 10th day post-infection (dpi), and the other half received treatment on the 90th day post-infection. Parasitological, histopathological, and immunohistochemical evaluations were performed. The docking analysis showed that the lowest estimated free energy of binding of annonacin, casuarine, L-epigallocatechin, P-coumaric acid, and ellagic acid toward C. parvum LDH, were −6.11, −6.32, −7.51, −7.81, and −9.64 kcal/mol, respectively, while NTZ was −7.03 kcal/mol. Parasitological examination displayed a significantly high difference in C. parvum oocyst mean counts in groups I and II compared to group III (p-value < 0.001), with group I demonstrating the highest efficacy. The analyses of histopathological and immunohistochemical results revealed that group I showed restoration of the normal villous pattern without evidence of dysplasia or malignancy. A. muricata leaf has proved to be a reliable agent for Cryptosporidium treatment. This paper argues for its promising use as an antiparasitic agent and for the prevention of neoplastic sequels of Cryptosporidium infection.

Background: Toxoplasma gondii is classified as intracellular protozoa and is one of the major zoonotic parasites. Most warm-blooded intermediate hosts, including humans, are commonly infected by this parasite. The epidemiology of T. gondii infection in Egyptian horses is currently poorly understood. Methods: 420 blood samples were randomly collected from horses raised in four governorates in Northern Egypt (110 each from Giza and Kafr El Sheikh, and 100 each from Qalyubia and Gharbia) to investigate the existence of antibodies against T. gondii using a commercial ELISA kit, and to ascertain the risk factors for the infection. Results: the antibodies for T. gondii were found in 16.2% (68/420) of the examined horses, with no significant differences among the four studied governorates. The highest prevalence rate was observed in Giza. The results revealed that sex, breed, age, and contact with domestic ruminants or cats were recognized as potential risk factors. The high prevalence rate was found in mixed breed horses (OR = 2.63, 95% CI: 0.95–7.26), mares (OR = 2.35, 95% CI: 1.31–4.19), and horses aged over 10 years (OR = 2.78, 95% CI: 1.30–3.44). Moreover, the likelihood of seropositivity for T. gondii infection was higher in horses raised in environments with cats (OR = 1.97, 95% CI: 1.13–3.44, p = 0.017) or domestic ruminants (OR = 2.16, 1.21–3.86, p = 0.010). This report confirms that horses in Northern Egypt are exposed to T. gondii and thus raises the possibility that people and other animals could contract the disease. Conclusions: routine examination and management of T. gondii infection in horses in these governorates is advised.

Glutathione S-transferases (GSTs) are enzymes involved in phase II of detoxification metabolism and could be used as biomarkers for water pollution. This study aims to determine heavy metal concentrations in the soft tissue of the mangrove clam Geloina expansa, as well as the expression of GSTs in the species. The acid digestion method was used to digest the samples, followed by a standard USEPA 6010B procedure using inductively coupled plasma optical emission spectrometry (ICP-OES) to measure the heavy metal contents in the samples. GST enzyme activity was measured using 1-chloro-2, 4-dinitrobenzene (CDNB) as substrate. One-way ANOVA was performed to compare the mean values of heavy metal concentration, protein concentration, enzyme activity, and specific activity. There was a significant difference (p<0.05) for Zn, total protein, and specific activity in G. expansa, but no significant difference in Pb, Cu and enzyme activity. GST enzyme activities were estimated at 0.16 ± 0.01 µmol/min, with a protein content of 1.24 ± 0.04 mg. The specific activity for GST was 0.13 ± 0.01 µmol/ min/mg, calculated as the ratio of enzyme activity to the total protein. GST-specific activity positively correlates with Pb concentration in the soft tissue of G. expansa. Detailed studies on the effects of pollution on the expression of GST need to be further investigated for the future use of this species as an efficient biomarker model. [ABSTRACT FROM AUTHOR]