Introduction: Leptospirosis is a re-emerging zoonotic disease of humans and animals worldwide. The disease is caused by pathogenic species of the genus Leptospira. These organisms are maintained in nature via chronic renal infection of carrier animals, which excrete the organisms in their urine. Humans become infected through direct or indirect exposure to infected animals and their urine or through contact with contaminated water and soil. This study was conducted to investigate Leptospira infections as a re-emerging zoonosis that has been neglected in Egypt. Methods: Samples from 1,250 animals (270 rats, 168 dogs, 625 cows, 26 buffaloes, 99 sheep, 14 horses, 26 donkeys and 22 camels), 175 human contacts and 45 water sources were collected from different governorates in Egypt. The samples were collected from different body sites and prepared for culture, PCR and the microscopic agglutination test (MAT). Results: The isolation rates of Leptospira serovars were 6.9%, 11.3% and 1.1% for rats, dogs and cows, respectively, whereas the PCR results revealed respective detection rates of 24%, 11.3% and 1.1% for rats, dogs and cows. Neither the other examined animal species nor humans yielded positive results via these two techniques. Only six Leptospira serovars (Icterohaemorrhagiae, Pomona, Canicola, Grippotyphosa, Celledoni and Pyrogenes) could be isolated from rats, dogs and cows. Moreover, the seroprevalence of leptospiral antibodies among the examined humans determined using MAT was 49.7%. Conclusions: The obtained results revealed that rats, dogs and cows were the most important animal reservoirs for leptospirosis in Egypt, and the high seroprevalence among human contacts highlights the public health implications of this neglected zoonosis.

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Oxygen free radicals have been implicated in the pathogenesis of diabetic microangiopathy. The production of superoxide anion (O2-.) by polymorphonuclear leukocytes (PMNs) from 45 insulin-dependent diabetes mellitus patients in the resting state and in response to a soluble stimulus (phorbol myristate acetate) was measured spectrophotometrically and compared with that of 15 age and sex matched controls. The resting superoxide anion production by PMNs from diabetic patients was significantly higher than that of controls (2.17 +/- 1.32 and 1.35 +/- 0.6 nmol/10(5) cells/60 min respectively; p = 0.037). In contrast, PMNs from diabetic patients released significantly lower levels of superoxide anion compared to controls in response to phorbol myristate acetate stimulation (2.33 +/- 2.04 and 3.55 +/- 0.98 nmol/10(5) cells/60 min respectively; p = 0.044). The stimulated superoxide anion production was significantly higher in diabetic patients with retinopathy compared to diabetic patients without retinopathy (2.7 +/- 2.08 and 1.3 +/- 1.6 nmol/10(5) cells/60 min respectively; p = 0.02). Furthermore, stimulated PMNs from diabetic patients with proliferative retinopathy generated superoxide anion at significantly higher rates than did those from diabetics with nonproliferative retinopathy or without retinopathy (3.8 +/- 1.5, 2.08 +/- 2.1 and 1.3 +/- 1.6 nmol/10(5) cells/60 min respectively; p = 0.005). These results suggest that reactive oxygen species produced by PMNs may play a role in the progression of diabetic retinopathy.

Oxygen free radicals (OFRs) have been implicated in the pathogenesis of diabetic microangiopathy. The effects of serum from insulin-dependent diabetes mellitus patients with or without retinopathy on the production of superoxide anion by normal polymorphonuclear leukocytes (PMNs) were measured spectrophotometrically and compared with that of age matched controls. Superoxide anion production by PMNs incubated with serum from retinopathy-free patients or patients with retinopathy was significantly higher than that of controls (P=0.0002 and 0.0001, respectively). Furthermore, superoxide anion production by PMNs incubated with serum from patients with retinopathy was significantly higher than retinopathy-free patients (P=0.02). These observations suggest that a diabetic serum factor provoked a significant generation of superoxide anion in normal PMNs, a phenomenon found parallel to the presence of retinopathy, indicating that OFRs may play a role in the progression of diabetic retinopathy. The nature of this serum factor remains to be clarified.

Aim:The present work aimed to develop lateral flow immunochromatographic strip (ICS) test for detection of Salmonella Enteritidis (SE) specific antibodies in chicken sera.Materials and Methods:A rapid lateral flow immunochromatographic test (LFIT) has been developed, in which SE Group D antigen labeled with the gold chloride molecules laid on the conjugate pad. Staphylococcus aureus protein A was used as capture antibody at the test line (T) of a nitrocellulose (NC) membrane and anti-SE antigen-specific rabbit antibodies were used as capture antibody at the control line (C) of the NC strip in the lateral flow layout device.Results:Using the developed LFIT, the minimal amount of SE-specific antibodies that can be detected in chicken serum sample was 1427 enzyme-linked immunosorbent assay (ELISA) unit/100 µl that was equal to 0.1 µg (Ab)/100 µl sample. 100 suspected serum samples collected from a poultry flock were tested with the prepared SE-LFIT kits and the locally prepared stained Salmonella antigen, and the results were compared with those obtained from examination of these samples with Salmonella Group D antibody ELISA kit as the gold standard test. The sensitivity, specificity, and accuracy of the prepared SE-LFIT antigen kits were 94.4%, 90%, and 94%, respectively, while those obtained with stained Salmonella antigen were 88.8%, 90%, and 89%, respectively.Conclusion:The developed test is a simple field rapid test of high sensitivity, specificity, and accuracy that can improve and facilitates rapid field surveillance of salmonellosis among chickens.

Hybridomas that secreted antibodies against aflatoxin B1 for multiple uses were prepared using a unique immunization schedule. Aflatoxin B1-BSA conjugate was used for immunization of Balb/c mice. Spleen cells were harvested from the hyper immunized mice to be fused with myeloma cell line (P3NS1) using polyethylene glycol 3000, 50% concentration as a fusogenic agent. The produced hybridomas were selected using HAT selective medium that was replaced by complete HT medium. From the 10th day after fusion, wells that contain colonies of hybridomas covering 30% or greater of the wells surface were screened for production of monoclonal antibodies against aflatoxin B1 using ELISA. 21 hybridomas were found to be reactive to aflatoxin B1. All were found to belong to IgG2a isotype except one was found to belong to IgM isotype. The prepared monoclonal antibodies and their application to immunoassays represents a useful and rapid quantitative measurement with high affinity and low detection limits in order to purify environmentally occurring levels of this carcinogen specially in areas at high risk for liver cancer.

In the presented study, we developed a nanogold lateral glow immunoassay-based technique (LFI-COVID-19 antigen test) for the detection of SARS-CoV-2 nucleocapsid proteins; the developed LFI-COVID-19 Ag test has been tested for limit of detection (LOD), cross-reactivity and interfering substances, and performance. It was found that the performance of the developed LFI-COVID-19 antigen test when it was evaluated by RT-qPCR indicated 95, 98, and 97% for sensitivity, specificity and accuracy, respectively. This complies with the WHO guidelines. It was concluded that the developed LFI-COVID-19 antigen test is a point of care and an alternative approach to current laboratory methods, especially RT-qPCR. It provides an easy, rapid (within 20 min), and on-site diagnostic tool for COVID-19 infection, and it is a cheap test if it is manufactured on a large scale for commercial use.

Isolation of Histoplasma farciminosum from five horses, showing typical signs of histoplasmosis farciminosi (epizootic lymphangitis) was successfully attempted. The mycelial form of H. farciminosum was isolated on Sabouraud dextrose agar enriched with 2.5% glycerol, brain heart infusion (BHI) agar enriched with 10% horse blood and PPLO dextrose glycerol agar. The last medium proved to be the most effective, both for primary isolation and subculturing of the fungus. It was found that on primary isolation, the lag phase of the mycelial form of the fungus was relatively long, involving 4-8 weeks at 25 degrees C. Colonies of the mycelial form of H. farciminosum appeared on subculture as a yellowish, light brown to deep brown, convoluted, waxy, cauliflower-like growth tending to form scant aerial growth. Conversion of the mycelial form to the yeast form of H. farciminosum was successful by subculturing either on BHI agar with 5% blood or on Pine's medium and incubating at 35-37 degrees C. Complete conversion to the yeast form was achieved only after 4-5 repeated serial transfers onto fresh media every 8 days. The yeast colonies were flat, raised, slightly or deeply wrinkled, white to light gray to grayish brown, and were pasty in consistency.