Archives of Razi Institute
Volume:70 Issue: 4, Autumn 2015

Leptospirosis is a zoonotic disease with global distribution that caused by pathogenic spirochetes of the genus Leptospira. Accurate diagnosis for differentiation of leptospirosis from other pyrogenic infections prevailing in the same locality and is imperative for proper treatment. Therefore a molecular diagnostic test with high specificity and sensitivity such as PCR is essential. Gene encoding of outer membrane proteins of Leptospira are potential candidates that may be useful as diagnostic and analysis of the disease. In this study, lipL21 gene was used for detection and differentiation of pathogenic from saprophytic leptospiral serovars in PCR assays. The leptospiral lipL21 gene expressed only in pathogenic Leptospira spp. The bacteria were inoculated into the EMJH (with 5% rabbit serum) and extraction of the genomic DNA was done by standard Phenol-Chlorophorm method. The specific primers for proliferation of lipL21 gene were designed. The lipl21 gene was observed in pathogenic leptospira and was not in saprophytic leptospires. The specificity and sensitivity of PCR was evaluated. PCR assay with high specificity and sensitivity may prove to be a rapid method for diagnosing acute leptospirosis and designed a positive control to optimize this diagnostic test. The results showed that molecular detection of pathogenic leptospiras based on lipL21 gene can be used for laboratory diagnosis of leptospirosis.

Among the viruses infecting honey bees, chronic bee paralysis virus (CBPV) is known to induce significant losses in honey bee colonies. CBPV is an unclassified polymorphic single stranded RNA virus. Using RT-PCR, the virus infections in honey bees can be detected in a rapid and accurate manner. Bee samples were collected from 23 provinces of Iran, between July-September 2011 and 2012. A total of 160 apiaries were sampled and submitted for virus screening. RNA extraction and RT-PCR were performed with QIAGEN kits. The primers lead to a fragment of 315 bp. The PCR products were electrophoresed in a 1.2 % agarose gel. Following the RT-PCR reaction with the specific primers, out of the 160 apiaries examined, 12 (7.5 %) were infected with CBPV. This is the first study of CBPV detection in Iranian apiaries. We identified CBPV in the collected samples from different geographic regions of Iran.

Rotaviruses group A are the major cause of diarrhea in calves under one month and every year causes enormous economic losses. Serological and molecular techniques can be used for rapid detection of rotaviruses but virus isolation requires specific methods of cell culture and suitable cell lines. In this study, 41 samples were collected from diarrheal calves up to the age of one month, from industrial and semi-industrial farms in Tehran and Alborz provinces. The samples were positive by RT-PCR on VP6 gene. After preparation and inoculation onto MA104 cells in roller tube culture and constant cell culture system, the cytopathic effect (CPE) was observed. Eligible cultured with CPE, were confirmed by two-step RT-PCR using VP6 gene primers. Semi-nested PCR using VP7 gene primers was also performed for G-genotyping in which 11 and 2 samples were detected as G6 and G10, respectively. This is the first report on isolation and identification of rotaviruses, one of the causative agents of viral diarrhea in Iran. The results of this research suggest that, these two types, can be used as the dominant strains for manufacturing a suitable vaccine against the rotaviruses in Iran.

Male guinea pigs show high susceptibility to Burkholderia mallei and have been used as animal models in glanders studies. The purpose of our study was to elucidate glanders comparative pathogenesis in guinea pigs. We present here the histological changes and bacterial isolation that develop over time in guinea pigs inoculated intraperitoneally (IP) with two strain of B. mallei. Ten male guinea pigs were inoculated intraperitoneally with either the standard strain of Burkholderia mallei or B. mallei strain from Siberian tiger at the Tehran zoo individually, then euthanized at multiple time points post inoculation. Histopathologic changes were similar in both groups and consisted of pyogranulomatous inflammation. In the standard strain study guinea pigs, changes were first seen at 48 hours in liver and heart then in spleen, lung, and kidney at day 3. These changes generally reached maximal incidence and severity by day 3 but decreased by comparison in all tissues except the liver, lung and kidney. Changes were first seen in Siberian tiger strain study guinea pigs also at 48 hours in lung, liver and spleen. At day 3, changes were present in liver, spleen and mediastinal lymph nodes. These changes were maximal at day 4 and 5. In contrast there are differences in incidence and severity between the two strain study guinea pigs. Our findings based on histopathological study indicate that Siberian tiger strain has more severity in gross and necropsy examination but in pathologic lesion was qualitatively similar generally. Additionally, by bacterial isolation, we confirmed the presence of B. mallei.

Human snake bitten poisoning is a serious threat in many tropical and subtropical countries such as Iran. The best acceptable treatment of envenomated humans is antivenoms; however they have a series of economic and medical problems and need more improvements. In this study a combinatorial human immunoglobulin gene library against some of Iranian snakes venoms was constructed. Total RNA prepared from peripheral blood lymphocytes of two recovered snake victims. RT-PCR was used for cDNA synthesis and amplification of the heavy (Fd segment) and kappa light chains of IgG antibody. After digestion of the heavy chain with SpeI and XhoI and light chain with XbaI and SacI enzymes, inserted successively into the cloning vector pComb3x, and then recombinant vector transformed to TG1 bacteria to construct the Fab library. For determination insertion rate of Fab segment into cloning vector, plasmids of 12 clones of library were extracted and digested with SfiI. Length of amplified Fd and κ chains, were 650 - 750 bp. Primary library size was determined to contain 4.9×105 members out of which half of them contained the same size of Fab fragment. This result is comparable to some researchers and shows that this method could be appropriate tool for the production of human polyclonal Fab fragment antibodies for management of poisonous snake bitted victims.

Intestinal coccidiosis, caused by Eimeria species, is an economically-important disease of poultry production industry worldwide. This study was designed to investigate the prevalence of different Eimeria species in the farmed broilers of Khoy city, West Azarbaijan, North West Iran. A total of 26 broiler farms of different production capacities were arbitrarily selected and examined in 2013. In each of the farms, Litters of two broilers farms were randomly sampled twice a week and examined. The intensity of infection with each of the Eimeria species was assessed on the basis of number of oocysts per gram of litter using Clayton-Lane and McMaster methods. Eimeria species diversity was determined by using oocyst sporulation technique in 2% potassium dichromate solution. Results indicated that 23.08% (6/26) of the broiler farms were infected with Eimeria oocysts. The maximum litter infection rate (7.5×103) was observed in fifth week of the rearing period. The litter infection rate was significantly correlated with kinds of water dispenser, feeder, ventilation, and density. The litters were infected with five Eimeria species; E. maxima (32.67%) in 6 farms (23.07%), E. mitis (24%) in 6 farms (23.07%), E. acervulina (18%) in 5 farms (19.23%), E. tenella (14.67%) in 4 farms (15.38%), and E. necatrix (10.67%) in 3 farms (11.58%). Results of this study uncovered high rates of litter infection with various Eimeria species in the studied farms, suggesting the establishment of firm health management strategies in the region.

The chitosan nanoparticles used widely as a drug delivery systems recently. In the present study the Echis carinataus snake venom loaded chitosan nanoparticles were prepared based on ionic gelation of tripolyphosphate and chitosan. The nanoparticles physicochemical characteristics, stability and biological activity of encapsulated venom were studied. The particles were spherical in shape and the tripolyphosphoric groups of TPP were linked to the ammonium groups of chitosan. Optimum particle size of chitosan and venom loaded nanoparticles were 89 and 116 nm, respectively. Optimum loading capacity and loading efficiency obtained by 500 µg/ml concentration of venom. The biological activity of venom remained intact during nanoparticle formation and showed no considerable reduction in stability analysis. Our results suggested that Chitosan nanoparticles, which prepared in this work possibly, could be used as an alternative for traditional adjuvants.

The present study reports the presence of N. caninum DNA by PCR in brain tissues of house sparrows. The results showed that 6 (2.8%) of brain samples were positive for N. caninum. This is the first report for detection of N. caninum in sparrows, in Khuzestan Province. The results suggest that the meat of infected sparrows can be the source for dog's infection.