A. Mahmoud

Inhibition of cadmium- induced genotoxicity and histopathological changes in Nile tilapia fish by Egyptian and Tunisian montmorillonite clay

Cadmium (Cd) is an important inorganic toxicant widely distributed in the environment because of its various industrial uses. The aims of the current study were to investigate the efficacy of purified Egyptian and Tunisian montmorillonite clays (EMC and TMC) to inhibit genotoxicity and histological alterations induced by cadmium chloride (CdCl2) utilizing the Nile tilapia fish as an in vivo model. Chromosomal aberrations (CAs), micronucleus (MN) frequencies and DNA fingerprinting profile were genotoxic end points and histopathological changes that were used in this investigation. Six groups of fish were treated for 2 weeks and included control group, CdCl2-treated group and groups treated with EMC or TMC alone or in combination with CdCl2. The present results revealed that, treatment of fish with CdCl2 exhibited significant increased in the number of micronucleated erythrocytes (MnRBCs), frequency of CAs and instability of genomic DNA. Treatment of EMC and TMC in combination with CdCl2 significantly reduced the frequency of MnRBCs by the percentage of 53.28% and 60.77% and the frequency of CAs by 43.91% and 52.17% respectively. As well as, normalized DNA fingerprinting profile and significantly improved histopathological picture induced by Cadmium treatment. It is worth mention that both clays have the ability to tightly bind CdCl2 and decreased its cytotoxicity and genotoxicity; however, Tunisian clay was more efficient in binding with the CdCl2 than Egyptian clay.

The role of ornamental goldfish Carassius auratus in transfer of some viruses and ectoparasites to cultured fish in Egypt: comparative ultrapathological studies

Goldfish, common carp and Nile tilapia were sampled between September 2002 and May 2003 to investigate lesions induced by viral diseases and ectoparasites. Goldfish exhibited neoplasms, Dermocystidium sp., Ichthyophthirius multifiliis (Ich), Trichodina reticulata, Lernaea cyprinacea and systemic infections. Neoplastic and systemic infections in goldfish were associated with viral infection. Oreochromis niloticus and Cyprinus carpio were mainly infested with several species of Trichodina and monogeneans. The presence of Dermocystidium sp. in carp, and viral particles in the liver and spleen of O. niloticus and C. carpio, was uncommon. Microscopically, intracytoplasmic inclusion bodies in the hepatic cells and lymphocytic infiltration in other internal organs of the three fish species were seen. Ultrastructural study showed enveloped viral particles in some cells in all fish species. The recorded parasitic infections were associated with degenerative, necrotic, inflammatory and proliferative changes in the skin and underlying muscles. Imported ornamental goldfish may be a source of infection to carp and native tilapia. Histopathology and transmission electron microscopy demonstrated the etiology and pathogenesis of infection and the preliminary diagnosis of viral infection, which is not common in Egypt. It is recommended that goldfish be excluded from edible-fish aquaculture ponds. Strict regulations regarding the transfer and quarantine of imported fish should be implemented.

Betanodavirus infection in reared marine fishes along the Arabian Gulf

Betanodavirus or nervous necrosis virus (NNV) is responsible for viral nervous necrosis (VNN) of fishes and is associated with mass mortalities of various fish species throughout the world. Here, we report for the first time Betanodavirus infection in Arabian Gulf region of the Kingdom of Bahrain. The present study is also the first report of mortality due to NNV infection in sobaity seabream Sparidentex hasta. NNV was detected in reared fry of gilthead seabream Sparus aurata and adults of sobaity seabream and brown-spotted grouper Epinephelus chlorostigma using nested PCR. In the present study, the rearing unit recorded 100% mortality in fry of gilthead seabream and 24 and 63% mortalities were recorded in different age groups of adult sobaity seabream due to VNN. Classical clinical signs of VNN such as body discoloration, loss of appetite and abnormal swimming behaviour were observed in fry of gilthead seabream. Histopathological studies revealed characteristic vacuolation and degeneration of brain and ocular tissues of sobaity seabream. However, brown-spotted grouper carried subclinical NNV infection, and there was no mortality in the group. Sequencing of nested PCR products and real-time PCR further confirmed the presence of the virus.

Lipoblastoma in a four-year-old African child.

A four-year old Sudanese child presented with a growing mass in the medial aspect of the right thigh. The mass appeared during the neonatal period. On clinical examination a diagnosis of lipoblastoma was entertained on the basis of the patients age and the clinical features of the mass. The tumor was completely excised surgically. The clinical diagnosis of lipoblastoma was confirmed pathologically. Follow-up of the patient for 6 months postoperatively showed no evidence of recurrence.