Iranian Journal of Parasitology
Volume:3 Issue: 1, Jan-Mar 2008

Toxoplasma gondii is an apicomplexan parasite which infects a broad range of hosts. The classical diagnosis of toxoplasmosis relies on serological methods. Detection of parasite or its components could be useful tool for early diag­nosis of the infection. Fifty mice were infected by the intraperitoneal route with 5000 tachyzoites of T. gondii RH strain. Five of them sacrificed every day from day 1 up to day 7 post infection. Sera and urine of mice were tested by capture ELISA. T.gondii antigens were detected from 3rd and 2nd day in serum and urine, respectively, after infection until their death on day 7. Antigenemia detection of antigens of parasite was possible in a short period of acute infection with T. gondii by capture ELISA.

Promastigotes of Leishmania spp. have been readily cultured, but the axenic culture of amastigotes has been successful in L. donovani, L. infantum L. mexicana and L. pifanoi. However, some species such as L. major, is much less amenable to axenic cultivation. In present study, we describe an in vitro culture system for the generation and propagation of axenic amastigotes form of L. major. Promastigotes of L. major were cultivated in a biphasic NNN medium. The liquid phase was Schneider''s medium, pH 3.5, supplemented by 25% FCS (fetal calf serum). The cultures were maintained at 33-34°C for 120 hours. Fine structure analysis of these in vitro-grown amastigotes by electron microscopy, demonstrated that they have a pear-shaped body with abortive short terminal flagellum. The in vitro-grown cells are agglutinated by peanut lectin. SDS-PAGE pattern of these axenic amastigotes showed a 66-kDa band, which was not present in promastigotes. The axenic grown amastigotes were able to infect peritoneum macrophages of BALB/c mice. In supernatant of culture, biochemical, analysis showed decreased protein and acid phosphate activity. These amastigotes like cells might serve as a suitable strain for the study of amastigote biochemistry, in vitro drug testing, and immunology of L. major.

The prevalence of setariasis in cattle and cerebrospinal nematodiasis in sheep and goats were determined in two geographical regions of Iran. In two provinces of Iran: Mazandaran (zone I) and Qazvine (zoneII) where sheep and goats were suffering from symptoms similar to cerebrospinal nematodiasis, the peritoneal cavities of 763 and 1020 cattle were searched for adult Setaria sp. respectively. History taking of 4770 sheep from zone I and 25550 sheep and 3190 goats from zone II were per­formed for the presence and determination of cerebrospinal nematodiasis in sheep and goats. To study pathological changes induced in central nervous system 7 sheep from zone I and 4 sheep and 2 goats from zone II with symptoms similar to CSN were necropsied. Our findings revealed that 47% and 13.2% of cattle in zone I and II harboured Setaria digitata (99.45%) and S. digitata (67.12%) plus S.labiato-papillosa (17.46%) respectively. History taking showed that each year 2.53% of sheep in zone I and 1.65% of sheep and 1.25% of goats in some districts of zone II (e.g. Roudbar Alamout) suffered from symp­toms similar to cerebrospinal nematodiasis the main clinical signs of which were difficulty in hind limbs movement (lumbar paralysis). At necropsy, no lesions were observed macroscopically in the brains as well as spinal cords. But in a few cases, central nervous system were congested and edematous. Histopathological examination of CNS of necropsied animals showed mild leptomeningitis and eosinophilic and lymphacytic encephalomyelitis with numerous hemorrhagic tracts, degeneration and necrosis due to migration of the larvae. The cross section of nematode larvae was observed in the brain section of a sheep in zone I. The results of this study showed that setariasis of cattle is very prevalent in both region mainly in zone I and sheep and goats harbor low percentage of CSN but with marked pathological lesions.

Intestinal parasites of humans are important health problems of most communities, especially those situated in tropical and subtropical areas. This study was carried out in rural population of Mazandaran Province, northern Iran, during 2004-2005, with the purpose of achieving a better understanding of the distribution of intestinal protozoan parasites in this province. A total of 855 stool specimens were collected randomly from rural inhabitants (384 males and 471 females) and examined by the formalin-ethyl-acetate concentration technique. In addition, a modified version of the Ziehl-Neelsen tech­nique was used for the staining of Cryptosporidium and other intestinal coccidian parasites. The general prevalence of intestinal protozoans was found as 25%. The prevalence of every intestinal protozoan parasite was as follows: Giardia lamblia (10.2%), Entamoeba histolytica/dispar (1.2%), Dientamoeba fragilis (1.1%), Blastocystis hominis (9.8%), Entamoeba coli (5%), Endolimax nana (0.7%), Iodamoeba butschlii (1.3%), and Entamoeba hartmani (0.4%). The present study revealed that the prevalence of intestinal protozoan parasites among rural inhabitants of Ma­zandaran Province are still so high that implies performing special control measures.

Ticks are blood feeder acarians that feed on variety of animals and introduce a wide variety of molecules to their host immune system and some of them may stimulate host immune system to produce antibodies. This study was carried out to detect humoral immune responses following Boophilus annulatus infestation. Seven cattle were each experimentally infested with 10000 B. annulatus larvae and their humoral immune re­sponse to salivary gland; ovary and larval extracts were determined by ELISA. Measurements of serum antibodies level were recorded weekly, in a period of nine weeks post infestation. An increase of the antibody level was observed in all animals at one week post infestation and reached in a peak at week ninth, then decreased in week 9. Sera of infected animals showed approximately similar reactions to all of tissue extracts that might be due to the presence of common proteins in tick tissues and could be a candidate for immunization.

Ascaridia galli, the largest nematode of small intestine of birds, especially the native poultry, may give rise to serious illness, pathological defects and economical losses even in modern poultry production systems. Although various measures have been undertaken to vaccinate poultry against A.galli, no satisfactory results were obtained so far. However, there is no report on the efficacy of excretory-secretory (ES) proteins of A.galli larvae in immunization of poultry. Thus, the aim of the present research project was based on the use of the ES products of the larvae, in order to find the protective anti­gens. Five hundred native poultry were autopsied and adult A.galli was removed form their intestines. The eggs were harvested form the uterus of female worms and cultured at 25 ˚C in water containing 0.1 N sulphuric acid for almost a fort­night. The larvae were then freed mechanically and kept in Earl''s salt solution for a few days. The supernatant solution of alive larvae containing the ES products of the larvae, as well as the sonicated alive and dead larvae, was analyzed by SDS-PAGE. Many protein fractions of 15 kDa up to 200 kDa were demonstrated in lysate of these larvae. Using the serum of a hen, infected with a high numbers of A.galli, an immunogenic antigen was identified between 55 kDa to 72 kDa by Western blotting procedure. Finding the protein band between 55 and 72 kDa can be promising for preparation of vaccine, though more investigations are needed to prove the protective ability of this antigen.

Toxoplasma gondii infection is widely prevalent in many species of warm-blooded animals including human. The aim of this study was to determine the prevalence of antibodies to T. gondii from slaughtered sleep and goats by mod­ified agglutination test (MAT) in Kerman region, southeastern Iran. Altogether 1340 blood samples were collected from 562 sheep and 778 goats from April to September 2005 in Kerman slaughterhouse. The sera were examined for T. gondii antibodies by MAT using an antibody titer of 1:20 or higher considered positive. The statistical analysis was performed by chi-square test and logistic regressions to analyze the influ­ence of all examined factor (age, sex and type of animals) on seroprevalence of toxoplasmosis. Antibodies were found in sera of 262 out of 1340 (19.6%) samples. of 262 seropositive sera, 139 sheep (24.7%) and 123 goats (15.8%) were infected. Seropositive animals more than one year were 1.6 times more likely to be seropositive than the others were. Sheep were 1.5 times more likely to be infected than goats were (OR=1.53, 95% CI=1.15-2.04, p=0.004). Serological results indicated a widespread exposure to T. gondii among sheep and goats slaughtered in Kerman region and suggest that consumption of raw and undercooked meat of these animals can be a probable source of human tox­oplasmosis.

Acanthamoeba spp. are free-living amebas found in a wide variety of natural habitats. The high percentage of Acanthamoeba in different environmental sources represents a sanitary risk for public health especially contact lens users and immunocompromised patients. The aim of this study was to determine the presence of Acanthamoeba spp. in different environments such as water, soil, dust and ophthalmology wards. From March to November 2007, 80 samples were collected from numerous localities in Tehran city including university campus, Laleh park and ophthalmology center. Sample types were water, soil, dust, cow faeces and medical in­strument. Each sample was filtered through nitrate membrane and cultured on 1% non-nutrient agar. These plates were fol­lowed up daily for 2 weeks. Monitoring continued for two months on a weekly basis. Overall, 46.25% of samples contained Acanthamoeba spp. All of the soil samples had shown positive culture in contrast to tap water. Of 61 dust samples, 28 were positive. Interestingly, we were able to isolate Acanthamoeba in treat­ment unit of an ophthalmology center in Tehran. It should be mentioned that two cow faeces showed positive culture as well. The widespread distribution of Acanthamoeba spp. across the environmental sources and increasing numbers of HIV+ patients and contact lens wearers, as well as its ability as a pathogen carrier for humans, demands more awareness and knowledge for public as a risk for human health.

Hydatidosis is endemic in Iran. This disease frequently invades the liver and lungs. The frequency of multiple organ involve ment ranges between 11% and 30%. This study revealed a five -year-old female with missed multifocal and multior gan localization of hydatic cyst. The patient presented with a complaint of persistent fever and respiratory distress. In compute rized tomography (CT) of the thorax and abdomen, cystic lesions of different sizes in both lungs, massive pleural effusion were observed. Albendazole, praziquantel, cephazolin and aminoglycoside was started before surgery. Surgical intervention was planned for pleuropulmonary lesions of this patient. With early diagnosis and proper managements, hyda tid cyst in children has an excellent outcome. Today, it is believed that if the operation is performed after a brief course of albendazole or mebendazole, the success rates will be higher.

A vermiform specimen taken from a 10-year-old boy patient with the chief complain of sneezing, coughing and nasal dis-charge with a history of consumption of fast snack in the day before and liver of sheep in two weeks ago was referred for diagnosis to the Helminth Taxonomy Laboratory, Dept. of Mdical Parasitology and Mycology, School of Public Health, Tehran University of Medical Sciences, Iran in Dec. 2006. The specimen was processed and examined by light microscope and drew the features of specimen by Camera Lucida. Eventually, the specimen was diagnosed as third nymphal stage of Linguatula serrata.