Vol 5 No 2 (2010)
Recombinant SAG1 Antigen to Detect Toxoplasma gondii Specific Immunoglobulin G in Human Sera by ELISA Test
Background: Although some serological tests for the detection of Toxoplasma gondii-specific immunoglobulin are commercially available, better diagnostic tools are needed. The aim of present study was to evaluate the usefulness of the recombinant Toxoplasma gondii SAG1 antigen for the recognition of toxoplasmosis by ELISA.
Methods: This study was conducted in Cellular and Molecular Biology Research Centers, Shahid Beheshti University, M.C., Tehran, Iran in 2008-2009. Surface antigen 1 (SAG1), a tachyzoite stage-specific protein, was subcloned into an expression vector and was subsequently transformed into BL21 (DE3) pLysS competent bacterial cells. After inducing expression of the recombinant antigen, the protein product was purified using Ni-affinity chromatography. The immunoreactivity of recombinant SAG1 (rSAG1) was analyzed by SDS-PAGE and western blotting. The reactivity of the rec-SAG1 protein was evaluated using an ELISA.
Result: Sensitivity and specificity of the generated recombinant-ELISA (rec-ELISA) compared to a commercially available ELISA (com-ELISA) were 88.4% and 88%, respectively.
Conclusion: Recombinant SAG1 produced in E. coli is a promising antigen that can be used in diagnostic assays for the detection of specific antibodies against T. gondii.
Incidence and Genetic Characterization of Gongylonema pulchrum in Cattle Slaughtered in Mazandaran Province, Northern Iran
Background: The gullet worm, Gongylonema pulchrum Molin, 1857, is a thread-like spirurid nematode found in a variety of mammals worldwide. Its incidences in Iranian cattle of different breed or age have not been reported. The aims of the present study are to disclose the infection status of G. pulchrum in cattle slaughtered in northern region of Iran.
Methods: Full-length esophagi of cattle of 97 native dairy breed and 41 Holstein-Friesian breed were collected at four local abattoirs in Mazandaran Province, northern Iran, from March 2006 to August 2007, and were examined parasitologically. Eight overlapping segments of the small- and large-subunits of rDNA were amplified by PCR, and the obtained nucleotide sequences were characterized.
Results: The incidences of G. pulchrum in female and male native dairy breed were 38.9% and 24.0%, respectively, whereas those in female and male Holstein-Friesian breed were 4.2% and 0%, respectively. The first internal transcribed spacer (ITS1) region of G. pulchrum rDNA showed an intra-individual variation in the sequence and length, and the variation was ascribed to some unstable repeats of "A" or "CA".
Conclusion: Distinct incidences of G. pulchrum infection in native dairy breed and Holstein-Friesian breed might be ascribed to different animal husbandry manners for each breed in Iran; the former breed grazes freely in the pasture, but the latter breed is usually held in a pen. The rDNA sequence of Iranian G. pulchrum, obtained for the first time by us, might facilitate a reliable species identification of the parasite with a wide spectrum of morphological variations.
Background: Acanthamoeba is an opportunistic amphizoic protozoan found in different water sources including swimming pool as well as in sewage. The aim of this study was to investigate the prevalence of Acanthamoeba in tap-water samples in Iran.
Method: In this descriptive cross-sectional study, 94 samples of cold and warm tap-water were collected from different wards of hospitals in 13 cities of Iran in 2007-2008. Free residual chlorine, pH, and temperature of samples were measured. After filtration through multipore nylon membrane, samples were cultured on non-nutrient agar. Then we investigated existence of Acanthamoeba by reverse contrast phase microscope.
Results: Acanthamoeba was found in 45 samples (48%). Thirty-four and 11 positive samples were collected from cold and warm tap water, respectively. The samples belonged to the category of 20-30 °C temperature with 0-2 ppm free residual chlorine and pH 6-7.4 showed the most coincidence to the positive cases. The greatest proportion of positive samples was obtained from Mashhad hospitals, while all samples collected from Arak and Semnan hospitals were negative.
Conclusion: considering the results of this study and the pathogenic role of this protozoan on patients with immunodeficiency, as well as capability of this microorganism in carrying other pathogens such as Legionella, further studies are needed. What is more important, potable water in hospitals should follow the procedure of treatment and sanitation, in order to prevent the relevant nosocomial infections.
Background: This is the first work done on cryptosporidiosis among the children in Taiz, Yemen.
Methods: A number of 712 samples were collected from children of different ages (ranging from 1 month to 12 years) from Dec 2006 to Aug 2007. The collected samples were examined by Sheather's sugar floatation and Modified Ziehl- Neelsen stain as well as ELISA methods. The test results were statistically analyzed by SPSS software.
Results: The overall positive percentage was 43.7%. The higher incidence (36.2 %) was occurred in males while the lowest incidence (32.7 %) was observed in females (r= 0.876; P= 0.001). The correlation between infected cases and the type of drinking water was r =0.121. Among the cases examined by ELISA (92 cases), 26.1 % were infected. The correlation between seropositivity and gender was r= 0.652 (P=0.031).
Conclusion: Cryptosporidium spp. is a significant pathogen among children at Taiz. Fresh water supplies, education, eating habits and domestic animals are considered the main sources for transmission of cryptosporidiosis.
Onchocerciasis in the Upper Imo River Basin, Nigeria: Prevalence and Comparative Study of Waist and Shoulder Snips from Mesoendemic Communities
Background: Onchocerciasis is endemic in the Imo River Basin, Nigeria. This study was aimed at assessing the prevalence and intensity of microfilaria of Onchocerca volvulus in the area.
Methods: A cross-sectional study was carried out in the Okigwe Local Government Area, Imo State, Nigeria. Two skin snips (one from the waist and another from the shoulder) were taken from 1024 individuals examined. The survey coverage was high (91.8% of the study population). An individual was considered mf positive if either of the waist or shoulder snips or both were mf positive. The SPSS for Windows package was used for entering and analysis of data.
Results: Thirty-seven percentage of those examined was positive for Onchocerca volvulus microfilariae (39.2% of males and 34.9% of females). The mf prevalence increased steadily with increasing age to reach 70.4% in the oldest age group. The overall mf Geometric Mean Intensity among mf positive individuals was 16 mf/skin snip and was significantly higher among males (18 mf/skin snip) than females (14 mf/skin snip) (p < 0.01). A scatter plot of microfilariae numbers in snips from the waist against numbers in snips from the shoulder of the same individuals, showed close correlation (Pearson's correlation coefficient = +0.90; p < 0.01), and those with mf intensities below 10 mf/snip had a more scattering tendency away from the regression line than those with higher mf intensities.
Conclusion: Onchocerciasis is a public health concern in the area. Perhaps, 10 mf/snip is critical intensity threshold for reliable sampling using corneo-scleral punch.
Background: The present study was aimed to elucidate the status of intestinal helminth infections in canids of Moghan Plain, northwestern Iran.
Methods: Eighty-five intestine samples from dead or shot wild canids, 59 fecal samples from sheepdogs and 5 from red foxes were collected from 2006 to 2008 and examined in Parasitology department of Pasteur Institute of Iran.
Results: Generally, adult worms, larvae, and eggs of 13 species of various parasitic helminths were recovered. Necropsy examinations showed that 96.47% animals harbored at least one helminth species. The prevalence of different species in necropsy were Mesocestoides sp. 84.7%, Rictolaria spp. 55.3%, Macranthorhynchus hirudinaceus 45.9%, Toxocara canis 43.5%, Toxascaris spp. 35.3%, Joyeuxiella sp. 34.1%; hookworms; 22.4%, Taenia spp. 11.8%, Alaria spp. 2.4% and Dipylidium caninum 1.2%. Besides, eggs belonging to 10 species of parasitic helminths were identified in 46 fecal samples and generally, 30.9% of samples harbored eggs of at least one helminth species.
Conclusion: The high prevalence of various helminth infections among canids in Moghan plain and contamination of environment by helminths eggs may increase the risk of infection for native people.
Background: Toxocariasis is a common disease around the world. Our objective was to determine Toxocara seroprevalence in humans in the city of Isparta, Southwest Turkey, in respect of some determinants such as age, socio-economic level, residence in city center or rural area etc.
Methods: Five hundred and thirty four individual participants from Isparta center and 85 from Asagi Gokdere village were included in the study. T. cati specific antibodies were analyzed using excretory-secretory (ES)-enzyme-linked immunosorbent assay (ELISA) method.
Results: T. cati antibodies were detected as positive in 73 (13.6%) of 534 samples which were collected from subjects living in the city center and 24 (28.2%) of 85 samples from Asagi Gokdere village. Toxocara seropositivity was detected among 15.6% of whole study group. The seroprevalence of toxocariasis was significantly higher among subjects from village than in subjects from city center (P=0.001). While gender, high school education, source of the water which is used, family income and geophagia/eating nail behaviors were the features which were detected as being associated with toxocariasis seropositivity (odds ratios= 0.5; 6.52; 3.61; 0.43; 0.13 respectively), owning dogs or cats and hand washing were detected as being not associated with toxocariasis seropositivity (P > 0.05). Furthermore, Toxocara seropositivity was significantly higher among subjects in 0-10 than >40 year-old group (P=0.02).
Conclusion: It can be suggested that untreated lost pet population, environmental contamination, and way of life have influence on the epidemiology of toxocariasis.
Prevalence of Intestinal Parasitic Infections among Mentally Disabled Children and Adults of Urmia, Iran
Background: The prevalence of intestinal parasites infection in institutions for mental retardation of Urmia City, West Azerbaijan Province, Iran was investigated.
Methods: This descriptive - cross sectional study was carried out in of Urmia city in 2007-2008. Fecal samples of 225 less than 29 year old mentally disabled individuals were examined using direct smear, formalin - ether concentration. Beside their scotch tape samples were observed for Enterobius eggs. Statistical evaluation was performed by SPSS 10.
Results: Of 225 mentally retarded persons, 118(52.4%) and 107(47.6%) were female and male. The overall prevalence of infection was 20.4% and that of male, and female were 20.5% and 20.3%, respectively. 17.3% of examined individuals had protozoa infection and 3.1% showed Enterobius vermicularis eggs. The infection rates of detected intestinal protozoa were Entamoeba coli 9.7%, Giardia lamblia 6.2%, Iodoamoeba butschlii 5.7%, Blastocystis hominis 4%, and Entamoeba histolytica/dispar 0.4%. Forty percent of 1-5 year, 22.8% of 6-14 year, 22.2% of 15-18 year, and 16.8% of more than 18-year age groups, had positive results in their tests. According to IQ test results, 23.8% of less than 25 score group, 19.6% of 25-50, 17.2% of 50-75, and 40% of 75-90 groups were infected.
Conclusion: More efforts for increasing sanitation level and prompt diagnosis and treatment of infected persons in these institutions are necessary.
Hydatid disease is the most common infections worldwide, but it rarely involves multiple organs. Herein, a 12-year-old boy is presented, who was admitted to Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran with symptoms of irritability, sleepless, and weakness of the extremities. Patient's brain computed tomography (CT) scan with contrast media showed large multilocular cystic lesions in right temporal lobe associated with two other smaller similar cystic lesions in centrum semiovale bilaterally. Abdominal sonography revealed intestinal mesenteric and a cardiac cyst. Abdomino-pelvic CT scan showed a cyst medial to the cecum and a cortical cyst in the left kidney as well as a heart cyst. The echocardiography confirmed hydatid cysts at apical and interventricular septum. Serology test was positive for hydatid cyst. Albendazole and praziquantel were started for the patient immediately and right temporal lobe lesions were removed via neurosurgery intervention. After one month, cardiac and mesenteric cysts were operated during two separate surgeries. Pathologic findings of all cysts were compatible with hydatid cyst. Cystic hydatidosis should be suspected in any cystic mass, whilst prompt diagnosis and appropriate treatments are the keys in management of affected patients.
The First Record of Argulus foliacesus (Crustacea: Branchiura) Infestation on Lionhead Goldfish (Carassius auratus) in Iran
Argulus foliaceus (Crustacea: Branchiura), or the fish louse, is an ectoparasite of the skin or gill of the fresh water fish species. Clinical signs in infected fish include scratching on aquarium walls, erratic swimming, and poor growth. It causes pathological changes due to direct tissue damage and secondary infections. In the present study, lionhead goldfish (Carassius auratus), taken from a goldfish aquarium with symptoms such as abnormal swimming, poor growth and death, were examined for ectoparasites. The parasites collected from the skin and fins of fish were identified as A. foliaceus. Then, treatment was carried out by trichlorfon. After administration, no parasite was observed on the fish. This is the first report of infection with A. foliaceus of lionhead goldfish (Carassius auratus) in Iran.
Eristalis tenax, belonging to order Diptera, family Syrphidae seldomly causes intestinal myiasis. Intestinal myiasis caused by E. tenax larvae is a rare manifestation found in both humans and other vertebrate animals. We report a 22-year-old woman presented with this myiasis. The larva in her stool sample was identified as E. tenax related to its typical morphology and authentic clues. Lack of specific control measures in the domestic water supply system was the most probable cause of this infestation.