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   2014| July-December  | Volume 7 | Issue 2  
    Online since January 19, 2015

 
 
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REVIEW ARTICLES
Heat shock proteins and parasitic diseases: Part 1: Helminths
Sherif M Abaza
July-December 2014, 7(2):93-103
DOI:10.4103/1687-7942.149556  
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.
  2,280 273 2
ORIGINAL ARTICLES
Use of nested PCR-RFLP for genotyping of Cryptosporidium parasites isolated from calves and children suffering from diarrhea
Gehan S Sadek
July-December 2014, 7(2):129-137
DOI:10.4103/1687-7942.149568  
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.
  2,061 266 2
Heterophyid metacercariae in free living and farmed fish of El-Max Bay, West of Alexandria, Egypt
Mona H El Sayad, Sahar A Abou Holw, Omaima G Yassine, Hend A El-Taweel
July-December 2014, 7(2):110-115
DOI:10.4103/1687-7942.149560  
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.
  2,119 204 1
The epidemiology of Giardia intestinalis assemblages A and B among Egyptian children with diarrhea: A PCR-RFLP-based approach
Nora L El-Tantawy, Amira I Taman
July-December 2014, 7(2):104-109
DOI:10.4103/1687-7942.149557  
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.
  2,017 246 6
The efficacy of different commercial contact lens solutions on different concentrations of Acanthamoeba spp. trophozoites and cysts in Egypt
Yosra H Alam-Eldin, Heba A Aminou
July-December 2014, 7(2):122-128
DOI:10.4103/1687-7942.149564  
Background Acanthamoeba spp. keratitis is a devastating disease that can potentially result in threatening the sight of the affected eye. Ineffective lens-disinfecting systems and contaminated contact lens storage cases have been recognized as the main risk factors for the infection. Objectives The present study aimed to evaluate the efficacy of nine different commercially available contact lens solutions in the Egyptian market against Acanthamoeba spp. trophozoites and 2-week-old cysts. Materials and methods Nine solutions were tested: eight multipurpose solutions (MPS) and one one-step hydrogen peroxide solution. Acanthamoeba spp. was isolated from a keratitic patient, cultivated on 1.5% non-nutrient agar (NNA), harvested, adjusted in two final concentrations of 5 × 10 3 and 5 × 10 5 trophozoites and cysts, and then incubated with the contact lens solution. The efficacy was tested at intervals of 2, 4, 6, 8, 10, and 24 h. Experiments were performed in triplicate. The viability was confirmed by reinoculation onto NNA seeded with Escherichia coli (NNA-E. coli). Results Most of the tested solutions showed significant trophzoiticidal activity, whereas all of the tested solutions failed to eliminate the 2-week-old cysts completely. The one-step hydrogen peroxide system failed neutralization within the minimum manufacturer's disinfecting time as it killed all the cysts of 5 × 10 3 concentration after 10 h of soaking instead of 6 h; if used for this prolonged time, it could be hazardous to the users' eye. One of the MPS had high trophozoiticidal activity, but with an unknown recorded disinfectant, which could turn out to be of a toxic concentration or constitution. Conclusion Adjustment of the appropriate concentration of the disinfectant, the adequate exposure time, or even the development of new contact lens-disinfecting systems by manufacturers is needed to prevent Acanthamoeba spp. keratitis (AK). A MPS that fails to eradicate trophozoites or cysts within the minimum manufacturer's disinfecting time or one with an unknown recorded disinfectant should be avoided.
  1,859 218 1
REVIEW ARTICLES
Do protozoa play a role in carcinogenesis?
Eman K El-Gayar, Mohamed M Mahmoud
July-December 2014, 7(2):80-85
DOI:10.4103/1687-7942.149553  
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
  1,701 209 -
Travels and tourism are drivers for trichinellosis
Jean Dupouy-Camet
July-December 2014, 7(2):86-92
DOI:10.4103/1687-7942.149555  
Background Acquiring trichinellosis while traveling abroad is not a new phenomenon and imported cases are regularly reported worldwide. Cases contracted abroad and reported by the French National Reference Centre for Trichinella (NRCT) are analyzed here. Results Since 1998, 28 imported cases, representing 37% of all cases, were reported to the NRCT, with a mean annual incidence of two cases. Between 1975 and 1998, 40 imported cases represented only 1.5% of all identified cases, but with a comparable mean annual incidence of 1.6 cases. The incidence of imported cases could even have decreased since 1998 as the number of international travelers increased during that period. Since 1998, most cases were acquired in Canada from bear meat (hunters). Some cases were acquired in West Africa from warthog meat, in Laos from pork, and one case, in Algeria, was because of the consumption of jackal meat. Discussion These imported cases are most likely to occur in countries where the habit of eating raw meat is common and may show a high transmission in some regions where the disease is or had become unknown (e.g. Senegal, Laos, etc.). Backpackers, adventure travelers, or hunters will certainly be at a higher risk and should be informed about the risks of eating raw meat (pork, game, or reptile meat) and should be discouraged from illegally importing potentially infected meat that could introduce the parasite in Trichinella-free areas. Conclusion Travelers can be good indicators of the emergence of the parasitosis in a given country. Imported cases are good indicators of the epidemiology of the disease in countries where the original infection occurred.
  1,608 130 3
CASE REPORT
Giant swollen leg in type 2 diabetes
K.V.S. Hari Kumar, Sirisha Komala
July-December 2014, 7(2):138-139
DOI:10.4103/1687-7942.149572  
Type 2 diabetes mellitus is a common metabolic disorder with many short-term and long-term complications. Filariasis is a disfiguring disease seen mostly in tropical countries and is often resistant to all therapeutic interventions. We recently encountered an interesting patient with type 2 diabetes along with massively swollen right limb. We highlight the relevant differential diagnosis and plan to educate the readers about the occurrence of filariasis in diabetes.
  1,503 63 -
ORIGINAL ARTICLES
Microsporidia in diarrheic patients: detection and evaluation of intestinal inflammation and malabsorption
Amel A El-Sayed, Hend A El-Taweel, Sahar A Abou Holw, Safia S Khalil
July-December 2014, 7(2):116-121
DOI:10.4103/1687-7942.149563  
Background Early reports on microsporidial diarrhea involved mainly HIV-immunodeficient patients. More recent studies indicate that microsporidial spores may also be detected in immunocompromised persons not infected with HIV as well as in immunocompetent individuals. However, the exact mechanism of microsporidial diarrhea is not clearly defined. Objectives The aims of this study were to evaluate the contribution of microsporidia toward the burden of diarrheal diseases and to investigate the occurrence of associated intestinal inflammation and malabsorption. Patients and methods Stool samples of 237 patients with diarrhea were examined for microsporidial spores using modified trichrome stain. Microsporidia-positive samples were examined for concomitant parasitic infections. Intestinal inflammation was evaluated in patients infected solely with microsporidia ( n = 30) by comparing the fecal lactoferrin level measured by an enzyme immunoassay with that of a control group of healthy, age and sex matched, parasite-free nondiarrheic individuals ( n = 15). Fecal pH and assessment of fecal fat using oil red O stain were used as indictors of carbohydrate and fat malabsorption, respectively. Results Microsporidian spores were detected in 15.6% of diarrheic patients. Considering the median and range values, microsporidia-infected patients showed significantly higher fecal lactoferrin levels (median 49.75, range 2.8-220 μg/g, respectively) and lower fecal pH (median 5.82, range 5.12-6.98, respectively) compared with the control group (median 4.1, range 2.4-31 μg/g and median 6.7, range 6.3-7.16 μg/g, respectively). A significantly greater proportion of microsporidia-infected patients had elevated lactoferrin levels (>7.4 μg/g stool), markedly acidic stool (pH < 6), or increased fecal fat compared with the control group. Conclusion Infection with microsporidia is present in a considerable proportion of diarrheic patients and results in an intestinal inflammatory response as well as carbohydrate and fat malabsorption. Enteric microsporidiosis should be taken into consideration in the management of diarrheal diseases.
  1,404 149 -
FROM THE EDITOR
Report on EPU IV Conference 15-16 November 2014
Magda E Azab
July-December 2014, 7(2):79-79
DOI:10.4103/1687-7942.149552  
  768 72 -
SPOTLIGHTS ON NEW PUBLICATIONS
Spotlights on new publications
Sherif M Abaza
July-December 2014, 7(2):140-142
DOI:10.4103/1687-7942.149575  
  707 78 -
PARASITOLOGICAL RESOURCES
Parasitological resources
Khalifa E Khalifa
July-December 2014, 7(2):143-144
DOI:10.4103/1687-7942.149579  
  590 52 -