To a large extent, the development and cellular function of any organism are controlled by genes. A gene is the functional unit of inheritance controlling the transmission and expression of one or more traits. The gene is made from a DNA molecule which is copied and inherited across generations and from RNAs that code for a polypeptide or for a RNA chain that has a function in the organism. Gene mutation is a change in DNA nucleotide sequence of a short region of a genome. Alteration in DNA sequence affects all copies of the encoded protein resulting in structural and functional changes or decrease or complete expression loss of the encoded protein. Gene mutation may occur in either the parasite or the host, which may be beneficial or harmful for each. All through this review, the authors will focus on host or parasite gene mutations (causes and types) and their relation(s) to or effect(s) on parasitic diseases. The review presents examples of gene mutations in the host (part I) or parasite (part II) focusing on disease susceptibility or resistance, drug resistance encountered in several parasitic diseases, carcinogenesis, virulence, pathogenesis, and clinical outcome as well as their relations with insecticide resistance and vector control. Abbreviations: CM: Cerebral malaria, G6PD: Glucose-6-phosphate dehydrogenase; MBL: Mannose-binding lectin; mdr: Multi-drug resistance gene; NO: Nitric oxide; SNP: Single-nucleotide polymorphism; VL: Visceral leishmaniasis.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

Background Malaria has been documented as a major health problem in Saudi Arabia, and it is highly endemic especially in the Southwest (Jazan and Asir). Its control is considered a challenge; hence proper diagnosis is essential for implementation of successful control programs. Accordingly, the diagnostic test used should be easy, rapid, and reliable, besides it must be accurate and cost effective. Objective This work aims to study reliability and diagnostic accuracy of an immunochromatographic test (ICT) using BinaxNOW^® malaria test compared to microscopical examination of blood film as gold standard for malaria diagnosis among clinically suspected patients in Jazan area, KSA. Methods A cross sectional prospective designed study was done for 200 patients with prolonged fever attending Jazan general hospitals. Venous blood samples were collected for both microscopic examination of Giemsa-stained thick and thin blood and rapid ICT (BinaxNOW^®). Results Microscopic examination of Giemsa-stained blood smears revealed 64 out of 200 cases (32%) positive for Plasmodium spp.; 43 out of 64 (67.2%) were positive for P. falciparum; 12 (18.7%) had mixed infection including P. falciparum; and 9 (14.1%) belonged to other Plasmodium spp. of which 8 (12.5%) were P. vivax and one case (1.6%) was P. ovale. ICT showed 66 out of 200 (33%) cases with positive results for Plasmodium spp. and one sample gave an invalid result. The overall sensitivity and specificity of ICT were 97% and 96%, respectively. While for single P. falciparum infection sensitivity and specificity were 96.7% and 78%, respectively. Regarding Plasmodium spp. other than P. falciparum sensitivity was 91.6% and specificity was 100%. Conclusion The use of ICT complement to microscopy is of great value particularly in Jazan, KSA, where P. falciparum and P. vivax are the most prevalent Plasmodium spp. These methods help in expanding laboratory based diagnosis, and minimize malaria associated morbidity and mortality.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub] [CITATIONS]

Background Techniques used to diagnose Acanthamoeba keratitis (AK), a sight-threatening corneal infection, are either insensitive or time-consuming. Early and accurate diagnosis and appropriate therapy are the key to a good prognosis. Objective The objective of this study is to shed light on the efficacy of PCR in the diagnosis of AK in comparison with other diagnostic techniques. Patients and methods Corneal swabs and scrapings from 95 cases suspected to have AK were examined by microscopy, culture on non-nutrient agar seeded with the avian fecal Escherichia coli AFEC49, and by PCR targeting the 18S rRNA gene. Results The highest number of positive swabs and scrapings was detected by the PCR technique (5.26 and 27.37%, respectively), followed by culture (1.05 and 13.68%, respectively), and the lowest was detected by direct microscopy (0 and 7.37%, respectively). Corneal scrapings showed more positive cases than corneal swabs with statistically significant differences irrespective of the technique used. PCR results were significant versus culture (P<0.05) and direct microscopy (P<0.001). Out of the 26 positive cases, 20 were contact lens wearers, 13 were swimming pools users, five had a history of eye trauma, and five had undergone previous eye operation. Conclusion PCR proved to be a better technique for the detection of Acanthamoeba infection compared with direct microscopy and culture techniques. Scrape specimens are more efficient than swabs in detecting Acanthamoeba by different diagnostic techniques. The important risk factors of AK were contact lens wearers, use of swimming pools, a history of previous eye operation as well as eye trauma.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

Background Trichomonas vaginalis is the etiological parasite of trichomoniasis. Endosymbiotic Mycoplasma hominis can exist in T. vaginalis populations. However, its consequences are not yet known. Recently, T. vaginalis isolates positive for M. hominis as proven by PCR had greater cytopathic effects on human vaginal epithelial cells and also on Madin–Darby canine kidney cells in vitro. Objective This study aimed to detect the presence of M. hominis infecting Egyptian T. vaginalis isolates and to evaluate the pathogenicity of this association in vivo. Patients and methods Forty-five symptomatic and asymptomatic T. vaginalis isolates were obtained from Suez Canal and General Hospitals, Ismailia city, Egypt. All isolates were axenically cultivated in Diamond’s TYM medium, followed by DNA extraction and PCR using primer pair targeting 16S rRNA gene to detect M. hominis-infected isolates. Positive M. hominis PCR products were subjected to sequencing analysis. All isolates were experimentally inoculated intravaginally in female albino mice to assess the pathogenicity of different isolates. Results The detection rate of M. hominis-positive T. vaginalis isolates was 20% as determined with PCR. No statistically significant association was recorded between M. hominis-infected T. vaginalis among symptomatic and asymptomatic isolates. Experimental mice infection showed varying degrees of inflammation by the different isolates. Conclusion To our knowledge, this study is the first report of T. vaginalis infection by M. hominis among Egyptian isolates and it was deduced that the association of M. hominis and T. vaginalis does not affect the clinical presentation of vaginal trichomoniasis and does not cause enhanced pathological changes in infected mice.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub] [CITATIONS]

Background Major symptoms associated with blastocystosis include diarrhea, abdominal pain, fatigue, constipation, flatulence, urticaria, and skin rash. It may play a significant role in several chronic gastrointestinal illnesses such as irritable bowel syndrome (IBS). Objective The main objective was to identify Blastocystis spp. subtypes (STs) of clinical isolates obtained from three different groups of patients: IBS and non-IBS with and without gastrointestinal tract symptoms. The secondary objective was to evaluate the infectivity and pathogenicity of detected STs from each group in experimental rats. Patients and methods This study was designed as a case-control study. Stool samples were collected from patients attending Suez Canal University Hospitals. Only positive samples for Blastocystis spp. were included in the study and the three groups were identified (19 patients each). Blastocystis spp. STs were identified using seven pairs of primers (SB83, SB155, SB227, SB332, SB340, SB336, and SB337) to explore the relationship of different STs with different clinical presentations of each group. Detected STs, from each group, were then used to evaluate the infectivity and pathogenicity in experimentally infected rats monitored by parasitological and histopathological parameters. Results STs using seven different sequence-tagged site primers revealed 54 isolates with single infection and three isolates with mixed infection. ST3 was the most common one in the present sample of Egyptian population (56.1%) followed by ST1 (35.1%), then ST2 (3.5%), whereas 5.3% were mixed infection (ST1 and ST3). Conclusion Our results showed that the clinical outcome of blastocystosis is not likely associated with a specific ST, although some STs are predominant in other epidemiologic studies.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub] [CITATIONS]

Nanomedicine is defined as application of nanotechnology for treatment, monitoring, prevention, and control of biological diseases. To apply nanomedicine, the precise targets (cells and/or receptors) specific to the clinical disease should be identified and the suitable nanoparticles for delivery system to minimize the side effects of the original drug should be selected. One of these precise targets are macrophages, endothelial, dendritic as well as tumor cells. The main aim of the present review is to throw light on possible nanotechnology applications in parasitic diseases focusing on three main aspects: diagnosis, treatment, and vaccination.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub] [CITATIONS]

Background Dientamoeba fragilis was considered as a commensal amoeba that inhabits the large intestine. Later, its association with irritable bowel syndrome drew attention to its pathogenicity. Metronidazole (MTZ) is the most recommended drug for treatment of D. fragilis and other pathogenic intestinal protozoa. Many studies reported that it is not suitable for children because of its mutagenicity and carcinogenic potential. However, still more work is needed to establish new, effective, and safe therapeutic agents against D. fragilis. Aim of the work The present study aimed at evaluating the effect of different doses of the aqueous extract of Nigella sativa on D. fragilis in experimentally infected mice in comparison with MTZ as a standard drug. Materials and methods Isolates of D. fragilis were obtained from patients complaining of acute/chronic intermittent diarrhea or diarrhea alternating with constipation with/without abdominal pain. Histopathological examination of cecal tissue of experimentally infected and treated mice with three different doses of N. sativa (125, 250, and 500 mg/kg/day) was compared with that of mice infected and treated by two doses of MTZ (62.5 and 125 mg/kg/day) as the standard treatment. Infected untreated mice were used as the control group. Results Histopathological examination of cecal tissue of the infected untreated group showed different degrees of pathological changes, which completely disappeared with the highest N. sativa dose (500 mg/kg). Concentrations below 500 mg/kg produced less severe pathological changes than in untreated animals. N. sativa in high dose significantly prevented cytopathic effect in mice 1 day after infection and for five consecutive days. Conclusion N. sativa has a potential therapeutic effect against D. fragilis infection in an experimental in vivo study. We recommend double-blind controlled clinical trials in humans to assess the use of N. sativa in management of human D. fragilis infection.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

Background Giardiasis is an important common intestinal infection that occurs as a result of ingestion of cysts of the protozoan parasite Giardia lamblia. Several medications are available to treat giardiasis. Metronidazole and other chemical drugs currently used for treatment cause side effects, whereas ginger has been used for centuries as a herbal medicine, without harmful side effects. Objective With regard to the above-mentioned properties of ginger we were prompted to evaluate its anti-Giardia activity, as compared with nitazoxanide (NTZ) and phosphate buffer saline (PBS) as controls, and to establish a G. lamblia axenic culture that yields a large number of trophozoites. Materials and methods Fresh clinical isolates of G. lamblia were obtained from different patients with acute giardiasis. Trophozoites were cultured using Stone’s modification of Locke’s solution as an axenic culture medium modified by supplementing with bovine bile and heat-inactivated bovine serum. Ginger extract was prepared to give a final concentration of 20 mg/ml. In vitro assessment of effect of ginger was carried out after 24 and 48 h. For post-treatment evaluation, the viability of G. lamblia trophozoites was tested by their morphological criteria and dye staining (eosin stain 0.01%). Results The culture yielded a rich growth of G. lamblia trophozoites. Dead trophozoites stained pink with eosin and showed loss of morphological criteria. NTZ treatment significantly lowered the number of the parasites after 48 h (mean: 42.5±3.53/ml; P≤0.002), with a reduction rate of 92.93%, compared with PBS. Ginger treatment significantly lowered the number of the parasites after 48 h (mean: 55±7.07/ml, P≤0.004), with a reduction rate of 94.4%, compared with PBS. Conclusion The present study confirmed that ginger extract is equally active against G. lamblia as NTZ. More research studies are needed to highlight the physiological and molecular mechanisms of action of ginger and provide more scientific evidence of its effectiveness. Moreover, this simple G. lamblia axenic culture medium proved beneficial for evaluation of the susceptibility of isolates to antiparasitic drugs.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub] [CITATIONS]

Helminthic infections cause severe diseases (helminthiases) associated with significant morbidity and mortality worldwide. Many individuals are not aware of the risks and complications of helminthiases in reproductive health; hence, the infections are often neglected, leading to severe outcomes. These infections are often misdiagnosed and result in miscarriages, infertility, ectopic pregnancy, and increased risk of other conditions. Infected women of reproductive age often pass infections to their fetus during pregnancy and childbirth, which consequently affects their growth and development. In addition, the resultant morbidity affects the economic productivity and quality of life of individuals and communities. For the present review, both electronic (PubMed, Medline, EBSCO host, Science Direct) and manual literature were searched for relevant articles. The review highlights emerging issues on clinical manifestations, risks, and complications. Besides impairment of reproductive health in developing countries, helminthiases increase the transmission of viral, fungal, and bacterial infections, and promote stigma and sex inequality. The clinical and social impact of these neglected, forgotten infections largely considered to be of low public health importance is discussed. Because of the immense and increasing impact on global health and development, health professionals are encouraged to confer high priority to helminthiases.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub] [CITATIONS]

Background Drug resistance to treatment of fascioliasis with triclabendazole (TCBZ) has emerged in Sohag Governorate, Egypt. Nitroxynil belongs to the halogenated phenol group of fasciolicides. It is highly active against adult liver flukes. A nitroxynil metabolite is produced in the liver parenchyma adding to its flukicidal activity and augmenting its efficacy against late immature flukes that migrate through the liver tissues. Treatment with nitroxynil may be an effective replacement for therapy with TCBZ in cases of resistance. Objective The aim of this study was to evaluate the efficacy of nitroxynil in the treatment of fascioliasis by assessing its effect on teguments and durability of adult Fasciola gigantica and Fasciola hepatica worms. Materials and methods Infected cows were selected on the basis of clinical signs, and infection was confirmed by detection of Fasciola eggs in their stools. Nitroxynil was administered as recommended in two doses 15 days apart, and the animals were slaughtered 15 days after treatment. Fasciola worms collected from the bile ducts were identified and prepared for electron microscopy. Tegument changes were examined with scanning electron microscopy. Results The removed adult flukes of both species were moving sluggishly and appeared pale with no evidence of gut content. Scanning electron microscopy examination of these flukes revealed evidence of swelling of the tegument that showed regional variation in its severity. Loss of spines was also observed. Conclusion The present study demonstrated the flukicidal properties of nitroxynil, proving that the tegument is an important target for its action. Disruption of the fluke's main line of defense allowed the drug access to other internal tissues, leading to more widespread damage. Nitroxynil may be successfully used for treatment in case of resistance to TCBZ.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub] [CITATIONS]

List of contents 1. Plasmodium spp. 1.1. Introduction 1.2. Historical background 1.3. Applications 2. Leishmania spp. 2.1. Introduction 2.2. Applications 3. Trypanosoma spp. 3.1. African trypanosomiasis 3.1.1. Applications 3.2. American trypanosomiasis 3.2.1. Introduction 3.2.2. Applications 4. Toxoplasma gondii 4.1. Applications 5. Cryptosporidium spp. 5.1. Applications 6. Other protozoa 6.1. Babesia spp. 6.2. Microsporidium spp. 6.3. Giardia lamblia 6.4. Eimeria spp. 6.5. Trichomonas vaginalis 6.6. Entamoeba histolytica 6.7. Free living amoeba 6.8. Cyclospora cayetanensis 6.9. Blastocystis spp. 6.10. Theileria spp. Concluding Remarks References Abbreviations ASS: African sleeping sickness; BiP: Binding protein; BS: Bloodstream forms; CL: Cutaneous leishmaniasis; COWP: Cryptosporidium oocyst wall protein; CTL: Cytotoxic T-lymphocyte; Cy: Cytosolic; ER: Endoplasmic reticulum; GA: Geldanamycin; GP60: Glycoprotein 60; HSP: Heat shock protein; ITS: Internal transcribed spacer; KMP-11: Kinetoplastid membrane protein-11 gene; MAb: Monoclonal antibody; MCL: Mucocutaneous leishmaniasis; MHC: Major histocompatibility complexe; Mit: Mitochondrial; NO: Nitric oxide; PS: Procyclic forms; PTEX: Plasmodium translocon of exported proteins; sHSP: small heat shock protein; SSU: Small subunit; TL: Tegumentary leishmaniasis; TLR: Toll like receptor; VL: Visceral leishmaniasis; VSG: Variant surface glycoprotein.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub] [CITATIONS]

Heat shock proteins (HSPs) are highly conserved and immunogenic proteins that are shared among diverse groups of mammals and microbial agents. They are categorized into different families according to their molecular weight. HSPs are involved in a variety of cellular processes and essential to cell survival. They are also implicated in immune pathology and clinical manifestations of a variety of autoimmune diseases and/or metabolic disorders such as atherosclerosis, diabetes and systemic lupus erythematosus. Their role in antigen cross-presentation and cancer immunotherapy as well as initiators of immune response and targets of autoimmune attack was also reported. The objectives of the current presentation are to summarize the functional properties of HSPs and their role in innate and acquired immune responses, to throw light on their role in pathogenesis and parasites survival, to review the literature searching for new drug discovery and vaccine candidates for parasitic diseases, and finally to present their use in diagnosis and genotyping of some parasitic diseases. Heat shock proteins (HSPs) are highly conserved and immunogenic proteins that are shared CONTENTS Introduction 1. Functional Properties of HSPs 1.1. Innate immunity 1.2. Adaptive immunity: 1.3. HSPs as cancer vaccines: 1.4. HSPs as infectious disease vaccines 1.5. HSPs and apoptosis 2. Heat Shock Proteins and Helminthes 2.1. Schistosoma spp. 2.2. Echinococcus spp. 2.3. Strongyloides spp. 2.4. Trichinella spiralis 2.5. Filarial nematodes 2.6. Other helminthes Concluding Remarks References Abbreviations: APC: Antigen-presenting cell; CTL: Cytotoxic T-lymphocyte; E/S: Excretory/secretory; gp96: a member of HSP90 family; GST: Glutathione-S-transferase; HC: Hydatid cyst; HSP: Heat shock protein; IFN: Interferon; IL: Interleukin; MHC: major histocompatibility complex; NK: Natural killer; SEA: Soluble egg antigen; TLR: Toll-like receptor; TGF: Transforming growth factor; TNF: Tumor necrosis factor.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub] [CITATIONS]

The eicosanoid family includes prostanoids, leukotrienes, and other oxygenated derivatives. Prostanoids are a major class of the eicosanoid family derived from metabolism of arachidonic acid by the action of cyclooxygenase enzymes (COX). They are further subdivided into three main groups: prostaglandins (PGs), thromboxanes (TXs), and prostacyclins. PGs were first discovered as uterotonic substances in human seminal fluid in 1930. In the late 1950s to mid-1960s, their structures were studied and identified as being derived from unsaturated fatty acids. Prostanoids are produced by many cell types such as vascular endothelium, leukocytes, and the pathogens themselves. Prostanoid production is controlled by expression of different enzymes engaged in prostanoid biosynthesis, and by the distribution of different specific prostanoid synthases within those cells that determine their effect on the immune system. The production of prostanoids differs from one cell type to another; for example, dendritic cells predominately produce PG E ₂ (PGE ₂ ) and TXA ₂ , whereas mastocytes produce PGD ₂ . All inflammatory cells, including monocytes/macrophages, and neutrophils, are the main source of COX metabolites. Produced in response to various physiological and pathological stimuli, PGs are noted as key participants in autoimmune immunopathology, infectious diseases, and cancer. Other reports have shown that PGIs are formed by endothelial and smooth muscle cells, and TXAs are formed by platelets and lungs; PGI ₂ and some other PGs are produced by interactions between cells using enzymes in adjacent cells; for example, platelet-produced PGH ₂ is converted to PGI ₂ in the vascular epithelium. PGs secreted in the saliva of blood-sucking arthropods increase local blood flow and maintain the supply for feeding; they were also reported to increase immune suppression, allowing prolongation of attachment by ticks. Progressive studies demonstrated that, besides insects, pathogenic fungi, protozoa, and parasitic worms produce PGs. This review focuses on induced efforts to study prostanoids and their relation to different parasitic diseases. Abbreviations AA: Arachidonic acid; COXs: Cyclooxygenase enzymes; CyPG: Cyclopentanone; DC: Dendritic cell; GST: Glutathione-S-transferase; GA: Glycyrrhizic acid; MAP: Mitogen-activated protein; MIF: Macrophage migration inhibitory factor; NO: Nitric oxide; PBMC: Peripheral blood mononuclear cells; PG: Prostaglandin; PG12: Prostacyclin; PGE2: Prostaglandin E2; PL: Phospholipase; PPAR: Peroxisome proliferator-activated receptors; TGF: Transforming growth factor; TNF: Tumor necrosis factor; TP: Thromboxan receptor; TX: Thromboxane.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub] [CITATIONS]

Background Trichomoniasis is a sexually transmitted disease (STD) caused by the protozoan Trichomonas vaginalis. This infection is the most prevalent nonviral STD and may be symptomatic or asymptomatic. Accurate diagnosis is therefore necessary for specific treatment to facilitate control of infection and to prevent complication. Objectives The aim of the study was to evaluate different techniques for diagnosing trichomoniasis in symptomatic and asymptomatic patients. Patients and methods The present study included 85 nonpregnant female patients aged 18-50 years. According to the presence of symptoms related to vaginitis (discharge, itching, dysuria, dyspareunia, lower abdominal pain, and backache), patients were divided into two groups (symptomatic and asymptomatic). Vaginal samples were examined by wet mount, Giemsa stain, acridine orange stain (AO), and culture on modified diamond media in addition to PCR. Results The detection rate of T. vaginalis infection was 27.1, 28.2, 30.6, 35.3, and 57.1% using Giemsa stain, wet mount, AO, culture, and PCR, respectively. Giemsa stain, wet mount, and AO stain had a sensitivity of 76.7, 80, and 86.7%, respectively, when compared with culture. PCR detected all patients among the symptomatic and asymptomatic groups when compared with the culture method. The detection rate of T. vaginalis infection in symptomatic and asymptomatic patients by culture and PCR was 38.1 versus 51.8% and 27.3 versus 36.4%, respectively. The infection was commonest in the age range of 18-36 years. Conclusion The high sensitivity and specificity of PCR reported in this study offers a useful rapid screening tool and provides an excellent alternative for definitive laboratory diagnosis of T. vaginalis, particularly in asymptomatic patients, thus reducing spread and transmission of the infection as well as minimizing the complication sequels.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

Hydatidosis of the brain is a rare disease. The diagnosis is usually late because of its slow progression and absence of specific symptoms. This review attempted to throw light on some aspects of cerebral hydatidosis because of deficient clinical suspicion of the disease, and imaging investigations are sometimes inadequate and biopsy reports inconclusive. Thus, the literature pertaining to parasitic causes, the incidence, the pathogenesis, the clinical picture, the diagnosis, and the management of the disease were overviewed. Our intention was to alert parasitologists and neurosurgeons concerning this morbid and rare condition, and to emphasize the fact that parasitic infection should be suspected in cystic lesions affecting the brain, especially in endemic areas of the world. Moreover, we aim to discuss or derive an answer to some amazing aspects of the disease. These include its clear abundance in children and in young age, its unusual huge size in their brains, whether the brain is an accidental or a target location, its extreme rarity in domestic animal's brains, the usual failure of serological and immunological tests used for its diagnosis, the wide range of clinical manifestations and differential diagnoses, and the recent measures used for its treatment and control.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

Background The role of fish living freely in their natural habitats in the transmission of fish-borne trematodes is well recognized. Moreover, the role played by aquaculture fish has also gained great attention in the last few years. Objectives To investigate the rate, density, distribution of infection, and infectivity of heterophyid metacercariae in free living and farmed fish collected from El-Max Bay, a Mediterranean coastal bay in Egypt. The influence of freezing duration on the infectivity of the detected metacercariae was also evaluated. Materials and methods Tilapia nilotica and Mugil cephalus from both habitats were examined for encysted heterophyid metacercariae using a compression method. The density of infection was estimated by the number of metacercariae per gram of trunk tissue following artificial digestion. The distribution of infection was studied in snips taken from the head, gills, trunk, viscera, and tail. Infectivity of the collected metacercariae was tested in rats. The susceptibility of metacercariae to freezing was evaluated by assessment of their infectivity to rats after they were kept frozen at −15°C for 4, 7, and 14 days. Results Rates of infection with heterophyid metacercariae ranged from 11 to 23% in the different groups of fish. Free living fish had a significantly higher rate of infection and/or density as well as higher infectivity of metacercariae than farmed fish. Higher metacercarial density was observed in the trunk and viscera of the studied fish compared with the head, tail, and gills. Infectivity of the detected metacercariae decreased gradually with increasing duration of freezing. Conclusion Both free living and farmed fish can transmit Heterophyes parasites, the former being somewhat more important. The potential risk of human infection is considered to be high. Freezing for 2 weeks is an effective means of inactivating the parasite. Our results underscore the need to raise awareness among public health agencies, consumers, and aquaculture managers of the measures needed to reduce transmission of this intestinal fluke.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub] [CITATIONS]

Background The vast majority of human cases of cryptosporidiosis worldwide are caused by two species: Cryptosporidium hominis (C. parvum type 1), which causes infection in humans only, and Cryptosporidium parvum (C. parvum type 2), which causes infections in humans and animals. In Egypt, calves carrying the zoonotic C. parvum represent the largest farm animal source of infection for humans. Information on the source of Cryptosporidium spp. contamination is necessary for effective evaluation and selection of management practices for reducing the risk for cryptosporidiosis. Objective The aim of the study was to genotypically characterize Cryptosporidium spp. in a sample of isolates from calves and children suffering from diarrhea. Materials and methods One hundred stool samples were collected from diarrheic calves housed at the Tropical Diseases Clinic, Faculty of Veterinary Medicine, Cairo University. A total of 110 stool samples were also collected from diarrheic children attending the Gastroenteritis Unit, Abo El Reesh Pediatric Hospital, Cairo University. Each stool sample of children or calves was examined microscopically after staining with modified Ziehl-Neelsen stain for the diagnosis of Cryptosporidium spp. Positive samples were then subjected to nested PCR-restriction-fragment length polymorphism (PCR-RFLP) targeting Cryptosporidium oocyst wall protein (COWP) gene for determination of Cryptosporidium genotypes. Results Screening by modified Ziehl-Neelsen staining detected Cryptosporidium in stools of 40% of diarrheic calves. Nested PCR-RFLP analysis showed that all positive samples were related to C. parvum genotype 2 (C. parvum). In diarrheic children, screening diagnosed 12/110 (10.9%) positive cases; 9/12 (75%) of them were confirmed positive by nested PCR. RFLP analysis showed that 8/9 (88.9%) samples were C. parvum genotype 1 (C. hominis), whereas one sample was not digested. Conclusion Genotype 2 C. parvum is relatively highly prevalent in the sample of calves examined compared with genotype 1 in the sample of children, indicating that transmission of cryptosporidiosis among this sample of children is anthroponotic and not zoonotic. It is advised to include PCR-RFLP technique in routine clinical diagnosis and epidemiological investigations.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub] [CITATIONS]

Background Appendicitis is the most common acute surgical condition of the abdomen, and appendectomy constitutes one of the most common surgical operations worldwide. Gender, age, seasonal variation and leucocytic count have been investigated in many studies, however, causative parasitic agents of appendicitis are the most important. They differ from country to country. Objective The present study aimed to investigate parasitic infections as causes of appendicitis among patients attending Minia University Hospital, Minia Governorate, EL Minia, Egypt. Methodology This descriptive study was carried out during the period between October 2013 and March 2014. Among 100 patients treated by appendectomy with a prediagnosis of appendicitis, 55 were males and 45 were females. All patients with clinically prediagnosed appendicitis were subjected to an open appendectomy, in which a right Macberny incision was made, followed by delivery of the caecum, devascularisation of the appendix, base ligation and appendectomy. Removed appendices were preserved in 10% formalin, fixed, sectioned, stained with H & E and examined for histopathological changes and presence of parasites. The faecolith contents of the remaining portions of appendices were evacuated. A wet mount preparation from each specimen was subjected to light microscopic examination for detection of parasites. Results Parasitic infection was detected in nine appendectomy specimens. The presence of Enterobius vermicularis worms was confirmed in three cases by both histopathological and faecolith examinations. Eggs of Ascaris lumbricoides, Ancylostoma duodenale and Hymenolepis nana were detected in one case each by faecolith examination. Bilharzial granulomas were detected in three cases by histopathology. Interestingly, E. vermicularis and the eggs of A. lumbricoides, A. duodenale and H. nana were found to be associated with obstructive acute appendicitis, whereas bilharzial granulomas were observed in chronic appendicitis. Conclusion The study concluded that parasitic infections constitute only 9% of the surgically removed appendices. Schistosoma spp. and E. vermicularis were the most common parasitic recorded. The association of H. nana with acute appendicitis appears to be a novel finding. A combination of histopathology and faecolith examinations is necessary for detection of parasitic causes of appendicitis.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub] [CITATIONS]

Background The protozoan parasite Giardia intestinalis is a common childhood infection in developing countries that causes diarrheal illness. The majority of G. intestinalis isolates from humans are grouped into two distinct genetic assemblages A and B. The molecular epidemiological studies on G. intestinalis assemblages in humans are limited in Egypt. Objective This study was conducted to estimate the detection rate of G. intestinalis infection among a cohort of children suffering from diarrhea in the Dakahalia governorate, Egypt, and to correlate between clinical giardiasis and Giardia spp. assemblages in positive stool samples by PCR-restriction fragment length polymorphism (PCR-RFLP). Participants and methods A total of 311 diarrheal stool samples were examined microscopically for Giardia spp. infection. DNA samples were isolated from the stools of 103 (33.12%) positive samples with G. intestinalis, amplified with PCR, and digested with the XhoI enzyme for RFLP. Results Of the 103 samples, 64 (62.14%) were found to be assemblage B, whereas 32 samples (31.07%) belonged to assemblage A. Mixed genotype A and B was present in three samples (2.91%), and four samples (3.88%) were of undetermined Giardia spp. assemblage. The detection rate of assemblage B was higher in samples from children with persistent diarrhea, whereas assemblage A detection rate was higher in samples from acute diarrhea. Conclusion G. intestinalis causing diarrhea in children in the Dakahalia governorate, Egypt, predominantly belongs to assemblage B, indicating that human-to-human method of infection is more common than zoonotic method.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub] [CITATIONS]

Background Cestode tegument is the barrier that separates the parasite from the host, allowing it to develop and survive the hostile environment of the host. It is the only site for nutrient intake. Objective The present study was conducted to reveal the fine structural transformation of the tegument of Taenia pisiformis cysticerci (Cysticercus pisiformis) during development from egg to cysticercus stages. Materials and methods The present study records the development of C. pisiformis in experimentally infected domestic rabbits, with special emphasis on the ultrastructural variations within different stages of larval development using both scanning (SEM) and transmission (TEM) electron microscopes. Results Three to six days postinfection, the early developed scolex appeared as an invaginated thickening at the anterior end of the developed metacestode. The first development of the rostellar hooks and invagination canal was observed 1 week postinfection (PI), where the hooks appeared as minute conical bodies. Complete development of the invagination canal and hook crown was observed 2 weeks later, synchronizing with the onset of sucker differentiation. Fine structural transformation of the tegument included variations in the structure of microtriches (length, density, and shape); distal cytoplasm and parenchymal vesicles and inclusion bodies (size, shape, distribution, and electron density); and tegumental and parenchymal muscles (thickness, orientation, and distribution). Conclusion The tegument of different developmental stages of T. pisiformis cysticerci has the same basic pattern, with some variations in the subcellular structures, which supports the suggestion that T. pisiformis can be used as an experimental model in cysticerci research.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub] [CITATIONS]

Background Strongyloides stercoralis is an intestinal nematode that usually causes asymptomatic infection in immunocompetent individuals and reverts to life-threatening hyperinfection in immunocompromised individuals. Objective The aim of the study was to evaluate the effect of ivermectin (IVM) treatment on S. stercoralis larvae in-vitro cultured forms. In-vivo evaluation was performed by assessment of parasitological, histopathological, and ultrastructural changes in the lungs of mice with Strongyloides hyperinfection syndrome before and after treatment with IVM. Materials and methods S. stercoralis larvae were collected from agar plates cultures of positive stool samples from different areas in Menuofyia Governorate. The in-vitro study involved the examination of S. stercoralis larvae grown in agar plates (APC) after exposure for 2 h to IVM (15 μl/ml) by scanning electron microscope (SEM) and after 24 h for larval motility. In-vivo study involved 96 mice that were divided into four groups (24 mice in each). Group GI was immunosuppressed by dexamethasone and infected with S. stercoralis larvae; GII was immunosuppressed then infected and treated by IVM (0.5 mg/kg); GIII was infected with S. stercoralis larvae; and GIV was infected and treated by IVM. Fecal larval output was carried out on 1 ^st , 6 ^th , 11 ^th , and 13 ^th days postinfection (dpi); histopathological examination of the lung was conducted on 2 ^nd , 7 ^th , 12 ^th , and 14 ^th dpi; and lung ultrastructure study by transmission electron microscopy (TEM) was performed on 7 ^th and 14 ^th dpi. Results IVM caused severe destruction of S. stercoralis larvae detected by SEM after 2 h and resulted in their death after 24 h. In-vivo results recorded significant decrease in fecal larval output in the treated groups (GII and GIV) and in GIII in comparison with GI. The latter showed significant continuous increase in fecal larval output throughout the period of study. Histopathological and ultrastructural results showed marked pathological changes in GI that were still evident until the last day of the study. IVM induced mild improvement in lung tissues in GII in comparison with GIV. The latter showed obvious improvement with great preservation of lung tissue. In GIII, mild pathological effect of infection was still evident by the end of study. Conclusion Dexamethasone-immunosuppressed mice infected by S. stercoralis showed intestinal and pulmonary hyperinfection. IVM showed significant improvement of all parameters studied mainly in the immune group and was very effective on motility of S. stercoralis larvae in vitro.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

Cysticercosis is a parasitic disease caused by the larval form of the cestode worm Taenia solium. It is commonly manifested as subcutaneous, intramuscular, eye, or brain nodules. We report two cases in an 8-year-old male child who presented with a cheek nodule, and another in a 25-year-old man who presented with a flank swelling. Both cases were diagnosed by fine-needle aspiration cytology. The use of fine-needle aspiration cytology highlights the cytomorphological diagnosis of cysticercosis in subcutaneous and intramuscular nodules.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]

All forms of infectious microbes, such as viruses, bacteria and parasites, can induce an inflammatory immune response which, under toxic environmental conditions, can cause cancer cells to grow. Some parasitic species were documented to have carcinogenic activity, namely; Schistosoma hematobium associated with squamous cell carcinoma of the urinary bladder and the liver flukes Opisthorchis and Chlonorchis associated with cholangiocarcinoma of the bile duct. This review aimed to examine the association of selected protozoa in human cancer. CONTENTS Introduction Cryptosporidium parvum Toxoplasma gondii Trichomonas vaginalis Blastocystis hominis Plasmodium falciparum Concluding remarks References Abbreviations: Apc: expression of tumor suppressor; ASC-H: atypical high grade squamous cells; ASCUS: atypical squamous cells of undetermined significance; BCL2: B cell lymphoma; β-catenin: the coordinator of cell-cell adhesion and gene transcription; c-Myc: transcription factor; CTL: cytotoxic T lymphocytes; eBL: endemic Burkitt lymphoma; EBV: Epstein Barr virus; Fas: apoptosis stimulating fragment; HCT8: human ileocaecal carcinoma; HCT116: human colorectal carcinoma cells; IFN-g: interferon gamma; miRNAome: 18-23 nucleotide non-coding RNAs that regulate gene expression in a sequence specific manner; miRNAs: micro RNAs; NF-Kb: nuclear factor kappa light-chain; SCID: severe combined immunodeficient; SIL-H: high-grade squamous intraepithelial lesions; TLR4: toll like receptor 4; TNFα: tumor necrosis alpha; Wnt: a group of signal transduction pathways made of proteins that pass signals from outside of a cell through cell surface receptors to the inside of the cell; ZO-1: a tight junction protein encoded by the TJP1 gene in humans

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub] [CITATIONS]

Background Giardia lamblia trophozoites colonize in the upper small intestine resulting in diarrhea and various clinical manifestations, including abdominal pain, anorexia, and signs of malabsorption. A decrease in the level of trace elements might occur because of this absorption deficiency resulting from giardiasis. Experimentally, the excretory secretory product of G. lamblia trophozoites increased the level of reactive oxygen species in mice enterocytes. The levels of bilirubin, uric acid, and albumin are often used as major nonenzymatic oxidative biomarkers. Objective This study was designed to determine the effect of therapy by metronidazole (MTZ) and artemether (ART) on trophozoite and cyst forms in experimentally Giardia spp.-infected hamsters and to reveal the changes in iron (Fe), manganese (Mn), copper (Cu), and chromium (Cr) serum levels pretreatment and post-treatment. Another objective was to evaluate the impact of this therapy on serum levels of bilirubin, uric acid, and albumin as nonenzymatic oxidative stress biomarkers. Materials and methods Hamsters were divided into four groups: the control group I included two subgroups, Ia (noninfected, nontreated) and Ib (infected, nontreated); group II (infected and treated with MTZ); group III (infected and treated with ART); and group IV (infected and treated with combined therapy of MTZ+ART). Hamsters of all four groups were killed 5 weeks postinfection (PI) - that is, 2 weeks after treatment - to evaluate drug efficacy. Stool samples and duodenal contents were examined to count the number of G. lamblia cysts and trophozoites, respectively. Blood samples were also collected to estimate trace elements (Fe, Mn, Cu, and Cr) as well as nonenzymatic oxidative stress biomarkers (bilirubin, uric acid, and albumin). Results There was a significant reduction in trophozoite and cyst counts following treatment with ART alone (88 and 82.5%, respectively) as compared with the infected control group Ib. Treatment with MTZ alone and in combination with ART also yielded a very high percentage of reduction in both trophozoites (94.2 and 98.3%, respectively) and cysts counts (93.9 and 95.5%, respectively). The trace elements in serum of infected controls (Ib) displayed nonsignificant decrease in Fe and significant decrease in Mn levels as compared with their levels in noninfected hamsters of group Ia. Cu levels increased in the infected group and were still increased after treatment with either MTZ or ART but decreased to normal with the combined therapy. Cr levels showed no significant change in all groups. Uric acid increased in infected controls as compared with normal controls. Treatment with MTZ or ART alone decreased uric acid levels lower than normal, and the combination of both drugs normalized its levels. Evaluation of serum bilirubin levels in the infected group and in those treated by MTZ and ART alone did not show any statistically significant differences compared with the normal noninfected group. Treatment with the combined therapy yielded even slightly lower insignificant level. Albumin level also did not differ significantly except in the combined regimen where it was lower than the normal range. Conclusion The effect of giardiasis on the changes in the level of trace elements and nonenzymatic oxidative stress biomarkers is relevant in this study. The combined therapy produced significant parasite eradication and normalized the studied parameters with the exception of Mn and albumin levels, which were adversely affected and remained lower than normal. Further studies are needed to evaluate these data in undernourished and chronically infected hamsters.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub] [CITATIONS]

Background Cryptosporidium and Cyclospora spp. are worldwide emerging parasites in both immunocompetent and immunocompromised individuals. Objective This study was designed to compare Cryptosporidium and Cyclospora spp. detected in fish with the corresponding species isolated from humans, morphologically and genetically. Detection of any similarity could be considered of potential epidemiological importance. Materials and methods Intestinal contents of 35 Tilapia zillii fish and 50 human stool samples were stained and examined to identify Cryptosporidium and Cyclospora oocysts. Thirty male Swiss albino mice were divided into the control group (I) and the experimental group (II), which was further subdivided into four equal subgroups (IIa, IIb, IIc, and IId), that were infected with fish and human Cryptosporidium and Cyclospora spp., respectively. Two weeks later, all mice were killed; parts of their small intestines were subjected to histopathological examination and processed for transmission electron microscopy (TEM). DNA was extracted from frozen oocysts present in human stool samples and fish intestinal samples, and amplification was performed using specific primers for Cryptosporidium parvum and Cyclospora cayetanensis. Results Cryptosporidium and Cyclospora spp. of both fish and humans detected in mice intestinal sections were morphologically similar by both light and electron microscope. However, failure of DNA amplification of oocysts of both parasites in fish intestinal samples, following application of the specific primers, indicates that fish species were not identical to human species. Conclusion It can be deduced that species identified in fish are apparently not infectious to humans.

[ABSTRACT]  [FULL TEXT]  [PDF]  [Mobile Full text]  [EPub]