This study was conducted to investigate the pathogenesis of columnaris disease in African sharptooth catfish, Clarias gariepinus. Flavobacterium columnare infections were detected in 33 (22.9%) fish out of 144 fish collected and examined over a year, in Assiut, Egypt. The present study demonstrated that parasitic infestation increases the susceptibility of fish to columnaris disease and plays an important role in initiation of natural infection. A reproducible model of experimental infection was developed to help studying the pathogenesis using immersion with either skin or gill scarification of challenged fish. Fish challenged through immersion with scarification developed severe signs of infections and showed mortalities, while fish challenged without scarification did not develop typical signs of infection and survived until the end of the experiment. F. columnare strain SK8FC isolated from skin of naturally infected fish was used throughout the challenge study. The invasion of F. columnare was enhanced by either skin or gill abrasion. Clinical signs and mortalities were more severe and rapidly developed in the gill-scarified group than in skin sacrificed group. Immunohistochemistry staining and histopathology studies were conducted to investigate the target organs, the distribution of the bacterium, and the pathological changes. Immunohistochemical staining demonstrated that the skin and gills were the main organs of F. columnare localization and the main organs expressing histopathological alterations. Skin and gill tissues were more strongly stained for F. columnare in scarified groups than in non-scarified group.

The emergence and spread of methicillin resistant Staphylococcus aureus (MRSA) infections are considered a global health issue. This study was designed to determine the prevalence of MRSA in milk from dairy herds and markets. The role of milk handlers as a source of MRSA infection had been studied. Genotyping of the isolated MRSA strains was investigated. A total of 100 samples of farm milk and market milk (50 each) as well as 30 hand swabs of milk handlers were collected randomly from Assiut Governorate. Methicillin resistant Staphylococcus aureus was isolated and enterotoxigenic strains were investigated. Polymerase chain reaction (PCR) was performed to amplify the nuc gene in the isolated strains. Moreover, sequencing of the amplified PCR products and phylogenetic analysis was performed. MRSA strains were isolated from 13.85% of the examined samples (22% and 8% of the examined farm and market milk, respectively) and 55.6% of the isolated MRSA strains were enterotoxigenic. In this study, staphylococcal enterotoxin C was the most enterotoxin detected in the isolated MRSA strains with a rate of 90%. However, enterotoxin type B was detected in 10% of the isolated MRSA strains. In addition, 25% of MRSA strains isolated from market milk were enterotoxigenic with one strain belong to type C. Enterotoxigenic MRSA strains were isolated with a rate of 66.7% from milk handlers and enterotoxin type C was the type of toxin produced by these strains. Nuc gene was detected in 5 (27.8%) out of the 18 MRSA strains. Phylogenetic analysis of the amplified products sequences was done and the results were discussed. Public health hazard of MRSA was discussed and suggestive measures for control were explained.

The emergence and spread of methicillin resistant Staphylococcus aureus (MRSA) infections are considered a global health issue. This study was designed to determine the prevalence of MRSA in milk from dairy herds and markets. The role of milk handlers as a source of MRSA infection had been studied. Genotyping of the isolated MRSA strains was investigated. A total of 100 samples of farm milk and market milk (50 each) as well as 30 hand swabs of milk handlers were collected randomly from Assiut Governorate. Methicillin resistant Staphylococcus aureus was isolated and enterotoxigenic strains were investigated. Polymerase chain reaction (PCR) was performed to amplify the nuc gene in the isolated strains. Moreover, sequencing of the amplified PCR products and phylogenetic analysis was performed. MRSA strains were isolated from 13.85% of the examined samples (22% and 8% of the examined farm and market milk, respectively) and 55.6% of the isolated MRSA strains were enterotoxigenic. In this study, staphylococcal enterotoxin C was the most enterotoxin detected in the isolated MRSA strains with a rate of 90%. However, enterotoxin type B was detected in 10% of the isolated MRSA strains. In addition, 25% of MRSA strains isolated from market milk were enterotoxigenic with one strain belong to type C. Enterotoxigenic MRSA strains were isolated with a rate of 66.7% from milk handlers and enterotoxin type C was the type of toxin produced by these strains. Nuc gene was detected in 5 (27.8%) out of the 18 MRSA strains. Phylogenetic analysis of the amplified products sequences was done and the results were discussed. Public health hazard of MRSA was discussed and suggestive measures for control were explained.

Clostridium perfringens induced necrotic enteritis (NE) and subclinical disease have become important threats to poultry health and is one of the main causes of losses in broiler flocks due to high mortalities and reduction in growth rate as well as enterotoxemias in domestic animals and humans . The mechanism of virulence of C. perfringens, a bacterium causing necrotic enteritis in birds, results largely from its ability to produce toxins. A study was set up to look the rate of carriage of C. perfringens among broilers with different heath status, incidence rate of the different toxin genotypes of C. perfringens in healthy and diseased birds and, lastly, the relative abundance of cpe, cpb2 and netB virulence genes. Broiler chickens from healthy flocks were sampled by cloacal swabs, while intestinal and liver samples of birds suffering from necrotic enteritis were analysed. A total of 47 (83.9%) isolates was obtained from 56 examined pooled samples (n=4) of broiler chickens with clinical problems and 14 (51.85%) isolates were obtained from 27 pooled samples (n=4) from broiler chickens without clinical problems. Seroneutralization with mice or guinea pigs has been used to type each toxin, but this conventional method has some disadvantages. Therefore, we used a multiplex PCR (m-PCR) assay with primers amplifying fragments of alpha (cpa), beta (cpb), epsilon (etx), iota (iap), for genotyping of isolated C. perfringens strains. All 61 broiler chicken C. perfringens isolates were shown to carry the cpa gene but not cpb, etx and iA genes, signifying that all isolates represented type A. For the first time the associated profiles of the following virulence genes [ cpe, cpb2 (beta-2 toxin) and the newly described pore forming toxin gene (netB)] were determined among Egyptian isolated C. perfringens strains. None of the isolates contained the enterotoxin gene that may indicate the enterotoxin of C. perfringens does not play important role in the occurrence of Necrotic enteritis in broiler chickens. netB was almost always found in outbreak isolates, suggesting a positive correlation of netB toxin gene with the diseased status that may explain its role in the pathogenesis of the disease. Whereas cpb2 was found in healthy and diseased bird isolates that suggest there is a weak or no relationship between beta2 toxin and necrotic enteritis in birds. So this study throw novel insights into the presence and distribution of C. perfringens types as well as virulence-associated genes in field strains, which will help us to understand the pathogenesis of disease in poultry and more comprehensively characterize C. perfringens in future studies to put a suitable strategy for prevention and control.

Clostridium perfringens induced necrotic enteritis (NE) and subclinical disease have become important threats to poultry health and is one of the main causes of losses in broiler flocks due to high mortalities and reduction in growth rate as well as enterotoxemias in domestic animals and humans . The mechanism of virulence of C. perfringens, a bacterium causing necrotic enteritis in birds, results largely from its ability to produce toxins. A study was set up to look the rate of carriage of C. perfringens among broilers with different heath status, incidence rate of the different toxin genotypes of C. perfringens in healthy and diseased birds and, lastly, the relative abundance of cpe, cpb2 and netB virulence genes. Broiler chickens from healthy flocks were sampled by cloacal swabs, while intestinal and liver samples of birds suffering from necrotic enteritis were analysed. A total of 47 (83.9%) isolates was obtained from 56 examined pooled samples (n=4) of broiler chickens with clinical problems and 14 (51.85%) isolates were obtained from 27 pooled samples (n=4) from broiler chickens without clinical problems. Seroneutralization with mice or guinea pigs has been used to type each toxin, but this conventional method has some disadvantages. Therefore, we used a multiplex PCR (m-PCR) assay with primers amplifying fragments of alpha (cpa), beta (cpb), epsilon (etx), iota (iap), for genotyping of isolated C. perfringens strains. All 61 broiler chicken C. perfringens isolates were shown to carry the cpa gene but not cpb, etx and iA genes, signifying that all isolates represented type A. For the first time the associated profiles of the following virulence genes [ cpe, cpb2 (beta-2 toxin) and the newly described pore forming toxin gene (netB)] were determined among Egyptian isolated C. perfringens strains. None of the isolates contained the enterotoxin gene that may indicate the enterotoxin of C. perfringens does not play important role in the occurrence of Necrotic enteritis in broiler chickens. netB was almost always found in outbreak isolates, suggesting a positive correlation of netB toxin gene with the diseased status that may explain its role in the pathogenesis of the disease. Whereas cpb2 was found in healthy and diseased bird isolates that suggest there is a weak or no relationship between beta2 toxin and necrotic enteritis in birds. So this study throw novel insights into the presence and distribution of C. perfringens types as well as virulence-associated genes in field strains, which will help us to understand the pathogenesis of disease in poultry and more comprehensively characterize C. perfringens in future studies to put a suitable strategy for prevention and control.

Clostridium perfringens induced necrotic enteritis (NE) and subclinical disease have become important threats to poultry health and is one of the main causes of losses in broiler flocks due to high mortalities and reduction in growth rate as well as enterotoxemias in domestic animals and humans . The mechanism of virulence of C. perfringens, a bacterium causing necrotic enteritis in birds, results largely from its ability to produce toxins. A study was set up to look the rate of carriage of C. perfringens among broilers with different heath status, incidence rate of the different toxin genotypes of C. perfringens in healthy and diseased birds and, lastly, the relative abundance of cpe, cpb2 and netB virulence genes. Broiler chickens from healthy flocks were sampled by cloacal swabs, while intestinal and liver samples of birds suffering from necrotic enteritis were analysed. A total of 47 (83.9%) isolates was obtained from 56 examined pooled samples (n=4) of broiler chickens with clinical problems and 14 (51.85%) isolates were obtained from 27 pooled samples (n=4) from broiler chickens without clinical problems. Seroneutralization with mice or guinea pigs has been used to type each toxin, but this conventional method has some disadvantages. Therefore, we used a multiplex PCR (m-PCR) assay with primers amplifying fragments of alpha (cpa), beta (cpb), epsilon (etx), iota (iap), for genotyping of isolated C. perfringens strains. All 61 broiler chicken C. perfringens isolates were shown to carry the cpa gene but not cpb, etx and iA genes, signifying that all isolates represented type A. For the first time the associated profiles of the following virulence genes [ cpe, cpb2 (beta-2 toxin) and the newly described pore forming toxin gene (netB)] were determined among Egyptian isolated C. perfringens strains. None of the isolates contained the enterotoxin gene that may indicate the enterotoxin of C. perfringens does not play important role in the occurrence of Necrotic enteritis in broiler chickens. netB was almost always found in outbreak isolates, suggesting a positive correlation of netB toxin gene with the diseased status that may explain its role in the pathogenesis of the disease. Whereas cpb2 was found in healthy and diseased bird isolates that suggest there is a weak or no relationship between beta2 toxin and necrotic enteritis in birds. So this study throw novel insights into the presence and distribution of C. perfringens types as well as virulence-associated genes in field strains, which will help us to understand the pathogenesis of disease in poultry and more comprehensively characterize C. perfringens in future studies to put a suitable strategy for prevention and control.

However pesticides contribute to a dramatic increase in crop yields and help to limit the spread of certain diseases by controlling pests, there is a strong evidence for persistent CNS damage following acute or chronic exposure to pesticides. The present study was carried out to investigate the neuropathological effects of methomyl, the common used carbamate pesticide in agriculture, on the brains of Sprage-Dawley rats. Rats were divided into two groups and treated orally with one dose of methomyl (10 mg/kg b.w.) and (2 mg/kg b.w., three times weekly). After one week and 3 months, brains from first and second groups were taken for histopathological examination, respectively. Methomyl significantly increased the numbers of necrosed neurons in the hippocampus of both animal groups compared to untreated controls. Also, methomyl caused neuronal degeneration and necrosis in cerebral cortex, cerebellum and some motor nuclei and induced glial proliferation and vacuolation of neuropil. In conclusions, methomyl induced neuronal degeneration and necrosis particularly in the hippocampus of SD rats.

The goal of this study was to assess if oxidative stress, as measured by alterations in the concentrations of antioxidant enzymes in the liver and erythrocytes of cattle, could be induced following dl-ethionine administration. Whole blood, serum and liver biopsy samples were collected 0, 4, 7 and 10 days after intra-peritoneal ethionine administration to five cows. The activities of the antioxidant enzymes copper zinc superoxide dismutase (Cu, Zn SOD) and catalase were assessed in the liver biopsies which were also examined histopathologically. Significant increases in hepatic Cu, Zn SOD concentrations (P0.01) were noted on days 7 and 10 post-treatment. Hepatic catalase activity decreased significantly (P0.01) on days 4, 7 and 10 post-treatment and erythrocyte Cu, Zn SOD activity was significantly increased on day 10. Serum biochemical analysis revealed a significant increase (P0.01) in non-esterified fatty acid concentrations on day 4 and significant decreases in total cholesterol and phospholipid levels on days 4 (P0.05), 7 (P0.01) and 10 (P0.01). In this model system, dl-ethionine administration was effective in inducing oxidative stress particularly reflected in the liver

The balance between free radicals and antioxidants is disrupted in many diseases. This disruption may be attributed to a number of factors such as the inability of the cells to produce sufficient amounts of antioxidants, the nutritional deficiency of minerals or vitamins, and the excess production of reactive oxygen species. The purpose of this article was to explore the involvement of free radicals in the pathogenesis of diseases that affect animals including hepatic diseases, parasitic infestation, mastitis, kidney damage, and carcinogenesis.

Eighteen Rahmani lambs (initial body weight 30±1.3 kg and 5-6 months old) were used to determine the effect of different dietary fat sources on the performance, digestion coefficient of nutrients, ruminal parameters and carcass traits in a three months experiment. The animals were allotted into three groups, 6 animals per each. The animals of the first group were fed the control diet (without fat supplementation), while the animals of the second and third groups were fed diets containing 4% dried fat and 4% tallow, respectively. All experimental diets were formulated to provide the recommended levels of digestible energy (3.0 Mcal/kg diet) and crude protein (14.71 %) according to NRC publication (1985) for sheep. There were a significant (P0.05) differences in the average daily gain, daily feed intake (g/head/day), and feed conversion between the different experimental groups. Lambs fed ration contained 4% dried fat recorded the highest value in daily gain and the best feed conversion. The digestion coefficients of dry matter, crude protein, crude fibre and ether extract as well as the nutritive value (DCP and TDN) were significantly (P0.05) higher for ration containing 4% dried fat followed by ration containing 4% tallow compared to the control one. Ruminal pH values were significantly higher (P0.05) in lambs fed diet with 4% dried fat. Ruminal ammonia nitrogen and total volatile fatty acids concentrations were significantly (P0.05) decreased with supplementation of fat compared to the control one. Dressing percentages were increased significantly (P0.05) by feeding supplemental fat compared to the control group. It could be concluded that, lambs fed diet with 4% dried fat recorded the best performance and the highest digestibility and carcass traits.