Prevalence and Molecular Epidemiology of Cryptosporidium Infection in Clarias gariepinus Fish in Egypt.

PURPOSE: This study investigated the prevalence and molecular detection of Cryptosporidium spp. in catfish (Clarias gariepinus). METHODS: A total of 300 Carias gariepinus fish were collected from two freshwater sources: the Nile River (180) and drainage canals (120). The stomach and intestine epithelium of each individual fish sample were screened by modified Ziehl-Neelsen (mZN) staining technique for the detection of Cryptosporidium oocysts followed by the serological survey for detection of Cryptosporidium antibodies using Enzyme-Linked Immunosorbent Assay (ELISA) and molecular characterization using complemented DNA polymerase chain reaction (cPCR). RESULTS: ELISA showed higher prevalence of 69.3% than that prevalence obtained by mZN, 64% for the total examined Clarias gariepinus fish. Also, higher prevalence of Cryptosporidium infection 65.5% and 75.8% obtained by ELISA than 61.1% and 68.3% by mZN, in both fish groups from Nile River and Drainage canal, respectively. PCR analysis revealed the expected positive bands at 1056 bp. DNA sequencing and phylogenetic analysis proved that the positive-PCR Cryptosporidium isolate identified in the present study was Cryptosporidium molnari. CONCLUSION: Freshwater fishes (Clarias gariepinus) are subjected to a high infection rate with Cryptosporidium spp.; the drainage canals obtained fishes showed higher prevalence than that collected from Nile River which indicates an important public health problem and a potential risk of drainage canals in Egypt. ELISA showed higher prevalence of cryptosporidiosis than mZN, for the total examined Clarias gariepinus fish and phylogenetic analyses confirmed this protozoal organism to be a novel species of Cryptosporidium molnari.

Altered renal immune complexes deposition in female BWF1 lupus mice following Plasmodium chabaudi infection.

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease that has a mysterious relationship with malaria infection. The current study was designated to compare between the effect of the live and the gamma irradiated Plasmodium chabaudi infection on BWF1 lupus murine model. A total of 30 female BWF1 mice were randomly divided into three groups (10 mice/group) as follows: group (I) lupus group (lupus non infected); group (II) live malaria infected group (lupus + live malaria infection); and group (III) irradiated malaria-infected group (lupus + gamma irradiated malaria infection). Live P. chabaudi infection was accompanied with a decrease in survival rate and food consumption in comparison to the control group of mice while gamma irradiated P. chabaudi -infection was unable to do this effect. Additionally, live P. chabaudi infection was accompanied with an increased level of proteinuria and increased rate of immune complexes deposition in kidney. Moreover, infection with live, but not gamma-irradiated P. chabaudi was accompanied with an increase in nitric oxide (NO), hydrogen peroxide (H2O2), and malondialdehyde (MDA) levels in plasma of lupus mice. The levels of both total cholesterol and triglycerides in plasma of lupus mice after live P. chabaudi infection were obviously decreased in comparison to the control group. On the other hand, gamma-irradiated P. chabaudi infection resembled the control group. Our data revealed that infection of lupus mice with live but not gamma-irradiated P. chabaudi has several histological and biochemical effects.

Infection of Female BWF1 Lupus Mice with Malaria Parasite Attenuates B Cell Autoreactivity by Modulating the CXCL12/CXCR4 Axis and Its Downstream Signals PI3K/AKT, NFκB and ERK.

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease characterized by abnormal autoreactivity in B cells. Lymphocytes and their soluble mediators contribute to the disease pathogenesis. We recently demonstrated that infecting lupus mice with malaria confers protection against lupus nephritis by attenuating oxidative stress in both liver and kidney tissues. In the current study, we further investigated B cell autoreactivity in female BWF1 lupus mice after infection with either live or gamma-irradiated malaria, using ELISA, flow cytometry and Western blot analysis. The lupus mice exhibited a significant elevation in plasma levels of IL-4, IL-6, IL-7, IL-12, IL-17, IFN-α, IFN-γ, TGF-ß, BAFF and APRIL and a marked elevation of IgG2a, IgG3 and ant-dsDNA autoantibodies compared with normal healthy mice. Infecting lupus mice with live but not gamma-irradiated malaria parasite partially and significantly restored the levels of the soluble mediators that contribute to the progression of lupus. Furthermore, the B cells of lupus mice exhibited an increased proliferative capacity; aberrant overexpression of the chemokine receptor CXCR4; and a marked elevation in responsiveness to their cognate ligand (CXCL12) via aberrant activation of the PI3K/AKT, NFκB and ERK signaling pathways. Interestingly, infecting lupus mice with live but not gamma-irradiated malaria parasite restored a normal proliferative capacity, surface expression of CXCR4 and B cell response to CXCL-12. Taken together, our data present interesting findings that clarify, for the first time, the molecular mechanisms of how infection of lupus mice with malaria parasite controls B cell autoreactivity and thus confers protection against lupus severity.

Malarial infection of female BWF1 lupus mice alters the redox state in kidney and liver tissues and confers protection against lupus nephritis.

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease characterized by an imbalanced redox state and increased apoptosis. Tropical infections, particularly malaria, may confer protection against SLE. Oxidative stress is a hallmark of SLE. We have measured changes in the levels of nitric oxide (NO), hydrogen peroxide (H2O2), malondialdehyde (MDA), and reduced glutathione (GSH) in both kidney and liver tissues of female BWF1 lupus mice, an experimental model of SLE, after infection with either live or gamma-irradiated malaria. We observed a decrease in NO, H2O2, and MDA levels in kidney tissues after infection of lupus mice with live malaria. Similarly, the levels of NO and H2O2 were significantly decreased in the liver tissues of lupus mice after infection with live malaria. Conversely, GSH levels were obviously increased in both kidney and liver tissues after infection of lupus mice with either live or gamma-irradiated malaria. Liver and kidney functions were significantly altered after infection of lupus mice with live malaria. We further investigated the ultrastructural changes and detected the number of apoptotic cells in kidney and liver tissues in situ by electron microscopy and TUNEL assays. Our data reveal that infection of lupus mice with malaria confers protection against lupus nephritis.

What are the infectious larvae in Ascaris suum and Trichuris muris?

In the present study, larvae of Ascaris suum and Trichuris muris were investigated by light and electron microscopy after incubation in a hatching medium containing 89% phosphate-buffered saline (pH 7.4), 10% RPMI-1640 and 1% sodiumhypochlorite at 40 and 37 degrees C, respectively. The larvae were obtained from fertilised eggs of the worms during defined phases of development (A. suum, 36th-50th day of development; T. muris, once a week from week 16 to 20). Light and electron micrographs of the larvae gave evidence that the third larval stage of A. suum is probably the infectious stage. The first moult of the larvae had already taken place before the 36th day of incubation starting at day 1. After 36 days of incubation, only the second larval stage was found within eggs. Some of these larvae were coated by a separated sheath so that a second moult of the larvae is reasonable. On the other hand, no sheathed larvae of T. muris were found in the eggs incubated for 20 weeks in distilled water. No signs of moult were seen for 20 weeks neither on light nor on the electron micrographs. Therefore, in T. muris, the first larval stage is the infectious stage, which was proven by means of re-infections of mice 16, 18 or 20 weeks after incubation of the eggs.

Some species of the genus Myxobolus (Myxozoa: Myxosporea) infecting freshwater fish of the River Nile, Egypt, and the impact on their hosts.

Six Myxobolus species are described from Nile fish, five of which are new and one is redescribed: M. naffari Abdel Ghaffar et al., 1998 was recovered from the gills of Labeo niloticus and the mouth of Barbus bynni; M. caudatus sp. n. was observed in the tail fin of B. bynni; M. fahmii sp. n. occurred in the gills of B. bynni; M. imami sp. n. was found in the kidney of L. niloticus; M. intestinalis sp. n. was recorded from the intestine of B. bynni; and M. perforata sp. n. was found in the internal surface of the operculum of Hydrocynus forskalii. The histological effects of some of the Myxobolus infections present are described.