نشریه تازه ها در میکروب شناسی دامپزشکی
سال چهارم شماره 2 (پاییز و زمستان 1400)

Infectious Bronchitis Virus is a Gammacoronavirus responsible for huge economic loss to poultry industry worldwide. Poultry (Gallus gallus) is the major host of the virus, but IBV-like coronaviruses can infect different species of birds. To determine the role of different bird species in infectious bronchitis virus epidemiology, this work was conducted to detect Gammacoronaviruses in Tehran live bird market. Cloacal swabs were collected from three bird species including poultry, duck and turkey; the RNA was extracted by CinnaPure isolation kit; subsequently the complementary DNA was synthetized by RevertAid First strand kit. Polymerase chain reactions targeting two genes of the nucleocapsid and the spike were run on complementary DNAs synthetized in the previous step. Polymerase chain reactions successfully detected the spike and the nucleocapsid genes in 40% of poultry and 66.6% of turkeys, respectively. Phylogenetic analysis showed that gammacoronaviruses detected in this work were closely related to infectious bronchitis virus type 4/91. This work also introduced the circulation of gammacoronaviruses in different bird species from a bird market, this issue could be significant in the future epidemiologic studies. The findings also described that the nucleocapsid gene detection is much more effective than the spike gene detection in terms of gammacoronavirus monitoring.

Cryptosporidiosis is an important parasitic disease in livestock, poultry and humans that it has great health and economic importance. Propagation of this parasite in livestock and poultry can preserve the parasite cycle in the environment. Therefore, disease control in this host is associated with reducing the load of Cryptosporidium in environmental and ultimately disease control in humans. For detection of Cryptosporidium in pigeons, 100 domestic pigeons of different genera were sampled in four different seasons at 2018. After extracting the genome from fecal samples, Cryptosporidium SS rRNA gene was detected with a special primer. In 6 samples (6%), 1325 bp fragment related to Cryptosporidium SS rRNA gene was amplified (4 female and 2 male pigeons). Statistically, there was no relationship between the sex and the incidence of infection. Studies showed that out of 6 positive samples, 5 samples were detected in the cold season and only one sample in the warm season. Data analysis shows that in cold seasons, the rate of infection is significantly higher than warm seasons (11.36% vs. 1.78%) (P <0.05). The pigeons in Isfahan are infected to Cryptosporidium and it is necessary to carry out a proper control program in these birds as one of the hosts of this protozoan. Certainly, reducing the level of infection in pigeons can reduce the environmental contamination with the common pathogen between humans and animals.

Due to growing demand of human communities for livestock products, livestock farms have trended towards industrialization.Therefore, with increasing livestock production, the use of highly fermentable carbohydrates has increased in livestock diets. On the other hand, the incompatibility of the gastrointestinal tract of ruminants with this feeding method causes the occurrence of various metabolic diseases and reduces the herd's economic longevity. Research has also shown that adding antibiotics to cow diet increases growth, reduces feed conversion ratio, and improves production and reproduction. But the use of antibiotics for long-term increases antibiotic resistance in livestock and consumers of livestock products. Therefore, it seems necessary to find a suitable alternative to antibiotics such as probiotics. The use of yeast in ruminant nutrition improve to establish and maintain the balance of beneficial bacterial populations, increase fiber digestion, improve ruminal function, ruminal pH and reduce the occurrence of various metabolic diseases. Yeast diets have also to improve milk production performance, persistence in dairy cattle, and milk quality. Probiotics can reduce the risk of intestinal infections and inflammation by competing for food, producing antimicrobial compounds, neutralizing toxins produced by these microorganisms. Also, the presence of effective compounds such as beta-glucans and mannas in the yeast cell wall reduces poisoning by fungal toxins, especially in ruminants, and by stimulating the immune system and the production of digestive enzymes, plays an important role in the growth performance, production, reproduction and the immune system in ruminants.

Potomac Horse Fever (PHF) is an acute enterocolitis syndrome causing mild colic, fever and diarrhea in all life stages in horses. It is also responsible for abortion in pregnant mares. The agent of PHF was diagnosed as Neorickettsia risticii. PHF was first diagnosed as a livestock disease, by veterinarians in Maryland State of USA in horses living around Potomac River. Since, most of the cases of disease were recorded in July, August and September, then it was regarded as a seasonal disease. Later studies revealed that a trematode vector takes the role as a vector for transmission. Routine cell culture and PCR were used for clinical diagnosis of the PHF. Using indirect fluorescent antibody tests revealed positive cases in most places of Canada and America, which regarded as former contacts with the agent of disease. Neorickettsia risticii could not be seen in monocyte in prepared blood smears from clinical cases of horses and this is contrary to Anaplasma phagocytophilum which very easily seen in granulocytes of blood in infected horses. Neorickettsia risticii has been isolated from released trematodes from fresh water snails. PHF is not a contagious disease and infected horses could be kept near susceptible horses. PHF is not regarded as a zoonosis. It is concluded that related veterinarians to horse industry in Iran should be informed about the possible occurrence of disease.

The most economically significant bacterial pneumonias are pasteurellosis and mycoplasmosis as causative agents of reduction in production, weight loss, increasing mortality rates in dairy and fattening sheep herds. This study was conducted to determine the histopathological and molecular properties of lung lesions caused by pasteurellosis and mycoplasmosis in slaughtered sheep at Fariman. A total of 4960 lungs were collected from sheep slaughtered at Fariman abattoir in 2019-2020. 90 of 4960 (1.81%) lungs which were macroscopically suspected to be suffering from pneumonia were examined microscopically. The polymerase chain reaction test was carried out for molecular detection of Pasteurella multocida and Mycoplasma ovipneumonia. Furthermore, statistical analysis was performed using the Chi-square test and the data were analyzed by SPSS software version 20. The molecular analysis showed that 16 specimens (0.032%) were positive for P. multocida, but M. ovipneumonia was negative in all specimens. In the histopathological investigation, the most common lesion was suppurative bronchopneumonia (1.16%). In addition, there was no significant association between age, sex and season with P. multocida (P˃0.05). These findings revealed that P. multocida is one of the common cause of bacterial pneumonia in slaughtered sheep at Fariman and its histopathological characteristics are notable.

Trichomonas galline is a flagellate parasite of warm-blooded animals found in birds that is more perceptive and lunar. Other birds may also be infected. In this study of pigeon stratigraphy, the British killed broth in a diamond environment. After culturing the parasite, the samples were kept in an incubator at 37 ° C for 48 hours until the number of protozoa reached about 1000 parasites per ml of culture medium. Then in eight groups including one control and seven treatments (one metronidazole group and six treatments of eugenol essential oil) according to doses of 1.56, 3.125, 6.25, 12.5, 25 and 5 micrograms per liter, eugenol is used to create the desired dilutions to the culture medium. . . After placing the microplate in the incubator at a temperature of 37 degrees at the desired intervals of 1, 2, 6, 12 and 24 hours after culture, 20 microliters of each well was removed and with 20 Landa trypan paint. It was mixed with the lamellar corner and after 10 minutes the number of dead Englishmen compared to the living ones was counted. Mortality in the metronidazole group showed a significant difference at all times of the study (p≤ 0.05). At 1.56, 3.125, 6.25, 12.5, 25 and 50 μg / ml eugenol, the difference between the mortality rates at 6 and 12 hours was significant for all of them (p≤ 0.05). The difference between mortality at 1 and 2 hours at 1.56 μg / L eugenol was not significant. The results of the study fully indicate the appropriate effect of eugenol extract in high dilutions (untreated (1.56 μg / ml)) on trichomoniasis.

A number of 700 broiler chickens were selected and distributed based on Gumboro vaccination in two treatment and control groups at separate cages with normal feeding conditions. The general vaccination program included bronchitis, Newcastle disease and influenza. Gamburo vaccination used orally on days 14 and 20 in the treatment group but control group was not given. Antibody titers were measured for Newcastle disease and influenza by HI method and for bronchitis and Gamburo disease by ELISA method using biocheck kit. Based on the results in all samples, the mean titers at 45 days of age for Newcastle, influenza, Infectious bronchitis was 6.1, 4.20, and 2610, respectively, and the CV% of antibody titers was 31% for Newcastle, 49% for influenza, and 58% for bronchitis. The average Gamburo titer in the treatment group on days 1, 20, 33 and 45, were11800, 5727, 6325 and 5797.8, and in the control group were 11800, 4501, 2298 and 1087, respectively. The CV% of Gumboro titers in the treatment group was 37.5%, 42%, 37% and 48%, and in the control group was 37.5%, 58%, 94% and 138% respectively. The ratio of averages of bursa weight to body weight (Bursa index) at the day of 20 and 45 in the treatment group was 0.21 and 0.23 but in the control group were 0.10 and 0.14 respectively. Therefore Gamburo vaccine IBD 071IR Razi Institute has a significant impact  (P <0.05) on increasing the titer of  humoral antibodies and bursa index.

Theileria equi is a protozoan of the Apicomplexa phylum and the family Theileridae, before known as Babesia equi. This parasite is the main cause of equine piroplasmosis (horses, donkeys, zebras and mules). The disease has been noted not because of its rapid spread and devastating effects on horses and mortality in acute cases, but because of the economic losses caused by trade restrictions and limitations in areas where it is prevalent. In this study, blood samples were collected from 100 horses from four different regions in Varamin and then its result was investigated from the perspective of infection by stanining and molecular methods. Furthermore, the presence of infection in different groups including age, sex, breed, type of maintenance and bodily activity was collected and classified with the assistance of Excel 2010 software and afterwards we analyzed the data with SPSS software by version number 25 and also using chi-square test. Finally, we concluded that there was 7% contamination, which demonstrates that paying attention to this disease would be essential for veterinarians.

Leishmaniasis is a protozoan zoonosis that causes problems in public health. The use of pentavalent antimony compounds as chemical drugs in the treatment of cutaneous leishmaniasis are associated with various limitations and side effects.Today, the plant extracts and their derivations are the promising sources in herbal medicine. The purpose of this study was to evaluate the effectiveness of oil extract Pistacia atlantica from Uramanat area in Kurdistan province, Iran, on promastigotes of standard strain Leishmania major in vitro. In this study, 10, 15, 25, and 50% concentrations of oily extract were added to the plate containing promastigotes of Leishmania major. The effectiveness of different concentrations of extract was determined by MTT (3-[4, 5- (dimethylthiazole-2-yl]-2,5-diphenyltetrezolium bromide) colorimetric method and counting of living promastigotes. The results of present study showed, different concentrations of oil extract has an inhibitory effect on promastigotes of Leishmania and the extract 50% has the most effect. The results showed a significant different between  in the number of promastigotes of Leishmania major in different concentrations of extract and exposure times (24, 48, and 72 hours) (P≤0.05). The results show that extract of pistacia atlantica has an appropriate effect on Leishmania major in vitro. Therefore, it is suggested to  be evaluated the effect of the extract Pistacia atlantica on leishmaniasis wounds.

Antibiotics have long been the first line of defense against Escherichia coli infection, but they have lost their potency as the bacteria become increasingly resistant to treatment. The aim of this study was to evaluate the resistance to tetracyclines and the prevalence of tetA and integron class I resistance genes in E. coli isolated from broilers with colibacillosis. In this study, 96.6 % of Escherichia coli isolates resistant to one or both tetracycline antibiotics were studied. Experimental results showed that 98.2 % of tetracycline-resistant Escherichia coli bacteria isolated from lesions of colibacillosis carry tetA. The prevalence of class I integron gene was 98.2%. Also, 96.5% of the isolates of this bacterium carried both genes. Considering the results, the prevalence of tetA and integron class 1 genes in this study was significantly higher than other studies. This difference could indicate high antibiotic resistance in poultry farms in this region which emphasizes the need for cautious use of tetracyclines in poultry production to reduce the prevalence of E. coli resistant to these antibiotics.

Sars-Cov2 has spherical shape with many spike proteins viz, M,N,E and S. S protein of this virus has major role in attachement of the virus to host receptor Angiotension-converting Enzyme (ACE2) protein.The purpose of this study was evaluation of Sars-Cov2 reservoirs by phylogenetic analysis aminoacid sequences of S and Angiotension-converting Enzyme (ACE2) proteins in the differents animals. To perform the study whole genome and amino acid sequences of S protein of Sars-Cov2 and sequences of ACE2 protein of some animals and human were downloaded from NCBI and GenBank and subjected to phylogenetic analysis of their relationship using MegaX soft ware. The results obtained indicated that all Sars-Cov2 isolated from different geographical areas have similar origin. On the other hand, amino acid profile of S protein in the different viral variants showed several sequences. In addition, amino acid sequence of Human ACE2 was very close to camel, Swine and bats (Pteropus vampyrus and Cynoplerus phinx). Therefore the present study showed that gene mutation in surface protein coding sequence of corona virus and the similarity of ACE2 amino acid sequences in different animals cause emerging the new variants of corona virus in the different reservoirs. Hence it might increase the rate of transmission of the virus to human even after vaccination and herd immunity.

In this experimental study, 32 rats were anesthetized with 2% ketamine and 5% xylazine, ip. Then a shear wound was created on the back of each animal, measuring one cm2 in full thickness. Mice were divided into negative control, positive control (osrine), spring orange 75% and phenytoin 1% groups. In the experimental group, 2 g of ointment was applied twice a day as a thin layer on the surface. Wounds were monitored for 14 days. Sampling was performed for histopathological examinations on days 4, 7, 10 and 14 after wounding. Digiser software was used to measure wound shrinkage. In this study, the rate of angiogenesis, fibroplasia, epithelial formation, collagen deposition and infiltration of inflammatory cells were evaluated. On microscopic examination on day 4, epidermal and dermal damage was observed in the presence of blood clots and infiltration of inflammatory cells in the treated group and budding tissue forming in the 75% spring orange and phenytoin 1% honey groups. On day 7, bud tissue was detectable in the treated groups. In the group treated with honey, 75% of the cell density of bud tissue was lower than the other groups and collagen synthesis was higher than the other groups and the developing epithelial tissue was also detectable. On day 10, the density of inflammatory cells, blood vessels, and fibroblasts in bud tissue decreased. In the negative and positive control groups, 75% of the bud tissue appeared younger than honey and 1% phenytoin. Germ tissue in honey group 75% and phenytoin 1% showed lower cell density and higher collagen synthesis. In the honey group, 75% of the formation of epithelial tissue was more advanced compared to the 7th day. On the 14th day in the honey group, 75% of the mature bud tissue appeared to have low cell density and collagen fibers were thicker, regular and more mature than the other groups, and the covering tissue completely covered the wound surface. In the study of wound contraction, the results showed that the group treated with honey 75% had a higher improvement than phenytoin 1%, which was statistically significant.