Archives of Razi Institute
Volume:63 Issue: 1, Winter 2008

In order to identify predominant circulating types of infectious bronchitis(IB) virus in the period of 1999-2004 in Iran, samples(trachea, lung, kidney) from 150 various flocks showing respiratory signs suspected to be related to IB infection were inoculated to SPF eggs. Then allantoic fluids studied by RT-PCR and Nested PCR using group and type specific primers to probing Massachusset, 793/B and D274 types viruses respectively. Out of 150 tested flocks approximately 72% were IBV positive in RT PCR tests. Specific nested PCRs on RT- PCR products of tested samples revealed that 57 flocks (52.7%) had been infected by 793/B type IBV alone. Massachusetts type IBV also could be detected in 18 flocks (16.6%) alone. Thirty three (30.5%) flocks had been infected by 793/B and Massachusetts type IBV in combination. Collectively, there were 90(approximately 83%) flocks that were infected by 793/B type IBV. Our results showed that the predominant circulating serotype of IBVs during the study period was 793/B type. The 274D type did not detected in any flocks during this study. The co-existence of Masachusset and 793/B type’s viruses in the same times in 33 flocks revealed that Masachuset type virus vaccines have not conferred a proper immunity against 793/B type viruses.

In this study, the pathogenicity of A/Ch/It/5093/1999 H7N1 which had been isolated from chicken during the outbreak in Italy was assessed in chicken by experimental infection virus. Ten SPF chickens of four week-old were inoculated with this virus, and five chickens were inoculated with uninfected allantoic fluid. For determination of virus shedding, oropharyngeal and cloacal swabs were taken from experiment and control groups, on days 1-5 post infection (p.i.) and used in a reverse transcription-polymerase chain reaction (RT- PCR) assay for detection of avian influenza virus (AIV). On day (2-5 d.p.i.) certain organs such as lung, brain, liver and kidneys collected from dead birds for virus titration, and histopathological investigations. In this study we obtained high titers in oropharyngeal swabs in 48 hours p.i. (h.p.i.). The first clinical signs observed were anorexia and depression in chickens. The results obtained with the virus isolation were confirmed by RT-PCR. All of the chickens inoculated with A/Ch/It/5093/99 died between 2d.p.i and 5 d.p.i. (2-5 d.p.i). On day 1 to 3 d.p.i. relatively high titer of infectious virus could also be isolated from oropharyngeal swab 102.3 to105.9 50% egg infectious doses (EID50/ml), whereas virus shedding from the cloaca (101.5 to 103.2 EID50/ml) was considerably less. The present study was conducted to determine the pathogenicity of A/Ch/It/5093 H7N1 in chickens. In our data show that infection of chicken with H7N1 virus leads to viral replication on the respiratory tract resulting in severe lung damage. The most consistent and severely affected organ by this virus were lung, kidney and brain, severity of the lesions in each organ was probably related to tissue tropism.

Bluetongue is an infectious disease that primarily affects sheep. But due to serious socioeconomic consequence of it outbreaks on the international trade it has been included in the OIE notifiable diseases (list A). During 2007-8, total number of 130 blood samples gathered from suspected sheep to bluetongue disease in seropositive region including Khuzestan, Kurdistan, Fars, Ilam and Qum provinces. Blue tongue viruses were diagnosed in some animals by RT-PCR and nested PCR, by targeting S7 segment. This genome segment was sequenced and analyzed in 11 samples as a conserved gene in BTV serogroup. The phylogenetic evaluation showed that there were two distinct clusters. One cluster was significantly near to East BTV strains from China and India and also was classified with BTV9/16 from Turkey. The second group was very similar to West BTV strains from US, Africa and Europe. This cluster was categorized with BTV4 from Turkey.

Proteases play a key role in protein digestion in ticks and other haematophagous insects. Our understanding of blood meal digestion in digestive system of ticks can be very useful for better understanding of basic rules for control of ticks. Cells of the midgut endocytose blood components. Blood proteins uptake by midgut cells, suggesting the presence of proteases in the midgut cells. In this study, proteases which may be present in midgut cells of engorged female ticks (Hyalomma anatolicum anatolicum) have been studied. The midgut tissue from tick was dissociated to cells. The cells placed in a culture plate with special medium. Then cell extract was obtained from the in vitro cultured midgut cells. Then cells were rinsed in hypotonic solution. The cellular suspension was centrifuged and supernatant removed from cell membrane plette. Cell membrane proteins were isolated by Solution 2% of Triton X-100. Proteases assay performed by specific substrates for cytoplasmic proteins and Cell membrane bound proteins. Then, enzyme like trypsin, enzyme like chymotrypsin, carboxypeptidase B, cathepsin C, cathepsin B and cathepsin D were detected. Our results show that enzyme like trypsin is a membrane bound protein, but carboxypeptidase B, cathepsin C, cathepsin B and cathepsin D are included in the cytoplasm of mid-gut cells. There is no enzyme like chymotrypsin in mid-gut cells of tick.

In the present study three species of Compsobuthus are described from Khoozestan province in Southwestern Iran: Compsobuthus matthiesseni &Compsobuthus jakesi From Bushehr and Fars provinces in Southern Iran: Compsobuthus matthiesseni, Compsobuthus persicus & Compsobuthus jakesi. The samples collected by UV light during filed studies of RRLS collecting team in these parts of Iran.Morphologic and morphometrical characters are discussed.

Scorpion venoms contain of variety of peptides toxic to mammals، insects and crustaceans. Toxic peptides are the main factors in scorpion venom causing toxicity, (their amount being 1-3%of total venom.). Most of the scorpion toxins have been isolated from the venoms of scorpions in the family Buthidae. The scorpion Buthotus Schach belonging to the Buthidae family is widely found in the western region of Iran, but no published articles has been found to date on its venoms. Therefore in this study, we aimed to isolate and purify mammalian toxins from the venom of the scorpion Buthotus Schach present in Iran. For this study the crude venom was dialyzed against deionized water for 48 hrs., and centrifuged in order to separate soluble proteins from the insoluble mucoproteins and the soluble proteins was applied on a sephadex G-50 gel filtration. The toxicity of each fraction was determined by I. V injection to mice and toxic fractions were further purified by two steps ion-exchange (anion) and RP-HPLC chromatography. The purity of the final toxic protein fractions was checked and confirmed by RP-HPLC column & SDS-PAGE. Finally two neurotoxin s, termed BS311 and BS313 were purified. Results in this study showed that the LD50 of crude venom on mice is 84µg/mice and contain at least 20 peptides from high molecular weight to low molecular weight out of which two of the peptides which showed toxicity to mice were isolated and purified. LD50 of these toxins were determined to be 3 and 2. 17µg/mice respectively. The molecular weight of the purified toxins BS311 and BS313 were 7860and 7600 Da, respectively, as determined by SDS-PAGE. In conclusion this study showed that the main factor in the toxicity of scorpion (Buthotus Schach) venom is low molecular weight peptides.

A vervet monkey (Cercopithecus aethiops) housed at quarantine of Razi vaccine and serum research institute died following a few days of sickness. Multiple abscesses on the surface and inside the liver and enlargement of spleen with pinpoint white spot were the most prominent macroscopic features. We examined the organs of the dead monkey and Yersinia enterocolitica was isolated. In histopathologic examination of the liver, spleen and intestine sections, acute hepatitis, splenitis and enteritis were evident. This is the first report of fatal case of Y. enterocolitica infection in vervet monkey from Iran.