نشریه میکروبیولوژی دامپزشکی
سال هشتم شماره 2 (پیاپی 25، پاییز و زمستان 1391)

Cryptosporidium parvum is a zoonotic protozoan which causes disease in immunocompromised patients and newborn animals especially calves. The oocysts excreted by infected animals are introduced into the environment and water. Since the low number of oocyst can cause infection and there is no effective disinfectant against cryptosporidium، the investigation dealing with the cryptosporidiosis is of growing interest among many researchers. Therefore، they try to improve the existing isolation methods of C. parvum oocysts even in environmental samples with small number of oocysts، to obtain much purified oocysts for immunological and molecular studies. Different methods have gained some success on the isolation of cryptosporidium، but they didn’t result in obtaining completely pure oocysts. The aim of the present study was to try to develop an isolating system for bacteria free oocysts. For this aim، four flotation methods have been used to isolate the C. parvum oocysts from the feces، including NaCl floatation، sucrose floatation، ficoll gradient and 55% sucrose floatation. A floatation method based on 55% sucrose was evaluated as the best method for the primary isolation of Cryptosporidium oocytes. The nitrocellulose filter (with 3µm pore size) was used to remove bacteria and other contaminants. Our results suggest that the oocysts isolated using filtration were free of bacteria and the amount of pure oocysts was 30%. Although the amount of isolated oocysts was limited، the isolated pure oocysts can be used for proteomics studies.

Bovine immunodeficiency virus (BIV) is a virus of Retroviridae family and one of the most important immunosuppressive viral pathogens of cattle. In the recent years، BIV infected cattle and buffalo have been found around the world and also in Iran. Although most of global BIV sero-prevalence rates were reported in the range of 4% to 6%، the studies conducted in Iran report higher rates (20. 3% and 60%) than worldwide rates. This study was conducted to identify the prevalence of BIV in the central areas of Iran، particularly Isfahan and Charmahal va Bakhtiari provinces for the foundation of future epidemiological studies. In this study a total of 2290 blood samples were collected from dairy farms in these provinces (490 and 1800 cattle of non- industrial and industrial farms respectively). By using an enzyme linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) test، the overall rate of BIV infection was 1. 61%. For the Charmahal va Bakhtiari and Isfahan areas BIV prevalence was 5. 7% and 1. 12% respectively. The prevalence of BIV positive cattle in non- industrial and industrial dairy farms was 4. 5% and 0. 83%، respectively. The positive samples for the presence of proviral BIV pol gene were sent to Veterinary Laboratories Agency (VLA) to be sequenced. The results showed Iranian isolates were 100% similar to standard R29 strain (GenBank NC001413. 1).

In this study, the therapeutic effect of liquid and hydroalchol extracts of Calotropis spp. and Butalex on Haemoproteus spp. infection in pigeons was evaluated. In the first course of treatment, 24 infected and 6 non-infected pigeons with Haemoproteus spp. were selected from a pigeon flock by blood smear examination. Then, the pigeons were divided into 5 groups of six each. The liquid and hydroalcholic extracts of Calotropis were orally administered to groups 1 and 2 with 0.3 mg/kg dose for 7 days. Butalex (anti-Theileria) was intramusculary injected to the pigeons of Group 3 at once with 2.5 mg/kg dose, and groups 4 and 5 were regarded as control positive and negative with no administration drugs. At the end of the study, the blood smears were again prepared from wing vein in the pigeons of different groups and microscopically examined to calculate the parasitemia rate. The results showed that in group 3 (Butalex treatment), the prasitemia rate of infected pigeons reached zero percent (p<0.005), whereas in groups 2 and 3 the parasitemia rate did not change (P>0.05). In the second course of treatment, the infected and non-infected pigeons were divided into 5 groups of six pigeons each. The liquid extract of Calotropis with a concentration of 10 and 1000 times of initial dose was orally administred to groups 1 and 2 for 7 days. The liquid extract with a concentration of 100 times of initial dose was intramuscularly injected. The groups 4 and 5 were regarded as control positive and negative with no administration drugs. At the end of the study, the blood smears were prepared from a pigeon in each of the different groups and microscopically examined to calculate the parasitemia rate. The parasitemia rate in each of the treatment groups did not change either (P>0.05). Based on the results of two courses of treatment, liquid and hydroalcholic extracts of Clatropis spp. did not have any therapeutic effects on Haemoproteus spp. in pigeons; however, it was evident that Butalex can be used as an effective drug for the treatment of Haemoproteus infection in pigeons.

Genotype and pathotype characterization of Escherichia coli isolates through molecular methods at a specific geographical area is particularly useful in the evaluation of disease، epidemiology. Enteropathogenic Escherichia coli (EPEC) and shigatoxin-producing Escherichia coli (STEC) are among the most important E. coli pathotypes. In this study 80 fecal samples were collected from 11 healthy sheep flocks in winter and spring of 2011 in Garmsar district. Escherichia coli isolates were screened by multiplex-PCR for stx1، stx2، eae، and ehly virulence genes. Among fecal samples، 47 cases (58/75%) were diagnosed as STEC Carrier. Among 98 E. coli isolates، stx1/ehly (54/8%) was the predominant genotype. EPEC strains were not recognized in this study. Therefore، sheep might be a possible reservoir for STEC infection in Garmsar and can be transmitted to humans through consumption of lamb meat and other related products.

This study was to determine the prevalence of Malassezia in domesti animals (cattle، sheep and goat) in Kermanshah city. This descriptive–analytic study was performed on 190 domesti animals including: 86 cattle (45%)، 56 sheep (30%) and 48 goats (25%) during 12-month period from August 2011 until July 2012. Specimens were collected by using scraping method from different parts of the body (back، ear، armpit، groin and around anus). Sabouraud Glucose Agar (SGA supplement with olive oil) was used for the sample of culture and in addition to morphological study; other tests such as Tween absorbance، catalase and esculin hydrolysis were performed to identify different species of Malassezia. Sixty-three (33%) of animals were infected with Malassezia، comprising of cattle with 61. 9% (39 cases)، sheep with 20. 63% (13 cases) and goats with 17. 46% (11 cases) respectively. The frequencies of the isolated Malassezia species included M. furfur (35%)، M. Globosa (24%)، M. slooffiae (19. 5%)، M. restrikta (11. 11)، M. pachidermatis (8%)، and M. sympodialis (3. 17%). There was such an increase in the frequency of the lipophilic species that M. furfur was، by far، the most predominant yeast isolate.

Brucellosis is an important zoonotic disease in humans and animals. Brucellosis has been reported from most countries، but in some countries including Iran the disease is endemic. Consumption of milk and products of infected animals is a major transmission source of infection to humans. Since in most provinces of Iran such as Kurdestan province، cattle and sheep are kept close together، it is possible that animals are infected with non-specific Brucella species. The aim of this study was to use PCR in detection of Brucella species in milk، and also to detect the host specificity of Brucella abortus and Brucella melitensis in cattle and sheep. In this research، 60 milk samples from suspected cattle and 50 milk samples from suspected sheep in different villages of Kurdestan province were collected. DNA was extracted from all milk samples directly. In order to detect the Brucella spp. PCR was carried out using B4 and B5 primers on all extracted DNAs and in order to detect the B. abortus and B. melitensis، PCR was carried out with B. a، B. m and IS711 primers on all DNAs. Using PCR for detection of Brucella spp. 20 and 22 of milk samples were positive in cattle and sheep samples respectively. Using PCR، out of the 20 cattle positive samples، 9 samples were identified as B. abortus (biovar 1، 2 and 4)، and 2 samples were identified as B. melitensis. Also out of the 22 sheep positive samples، 15 samples were identified as B. melitensis and 1 as B. abortus (biovar 1، 2 and 4). Regarding the fact that in two milk samples of cattle، B. melitensis and in 1 milk sample of sheep، B. abortus were detected، the animals that were kept in close contact with each other may lose the host -specificity. Based on the results of this research، it is recommended that in order to detect Brucella spp. in milk samples. The vaccination status should be detected and using specific primers for detection of all biovars of Brucella abortus and Brucella melitensis، PCR and cultural methods should be carry out.

In order to determine the clinical coliform mastitis incidence rate in Iran´s condition، the milk samples were collected from 144 cases of clinical mastitis on Garmsar suburban dairy Farms. The milk samples were incubated on a specific culture media to isolate coliform bacteria. Results showed that 51 milk samples (34%) contained coliform bacteria. E. coli was isolated from 72% of infected milk samples and 62% of contaminated milk samples، but Klebsiella spp. and proteus volgaris were isolated only from infected milk samples. Klebsiella spp. and E. coli were the most current coliform bacteria isolated from infected milk samples. Acute mastitis was the most current type (64%) of coliform mastitis and subacute (31%) and per acute (5%) were the next current types، respectively. The only kind of coliform bacteria producing per acute type of mastitis was E. coli. The most current parity was second parturition، the most current sign of mastitis was the watery discharge and the most current quarter was the rear left. Ceftriaxone was shown to be the most effective antibiotic.

Pathogenicity and histopathology of five Listeria ivanovii isolates from sheep meat in mice were done. Swiss albino mice (18-22 g) were used as experimental animals. Three isolates were pathogenic and caused mortality within 2 to 6 days after intraperitoneal injection. The reisolation of the microorganism from different organs was done. Pathological changes in the liver، spleen، brain، kidneys and intestines were recorded