viral infection in cats: Application of some molecular methods used for its diagnosis.

Forty diseased cats and seven healthy control cats from different sex, ages and breeds had examined clinically to confirm presence or absence of clinical symptoms of disease (FP). Several tools including ELISA, gene expression analysis (qRT-PCR), DNA fragmentation test and apoptosis assay were conducted to determine the disease in cat tissues. Clinical symptoms in the form of depression, fever, anorexia, vomiting, diarrhea, dehydration, anaemia and leucopenia were recorded in the diseased cats while no clinical sings were observed in control healthy cats. ELISA results showed that all of diseased (n = 40) cats were positive while control cats (n = 7) were negative for FP viral antigen. After carrying out of ELISA assay, supportive treatment trials including fluid therapy, immunostimulant, antibiotics to overcome dehydration, restoring electrolytes imbalances, combating secondary bacterial infection were conducted but all diseased cats were died and control cats exposed to soft death. Gene expression analysis detected high levels of FP viral gene in several cat tissues in which ilium exhibited high viral expression levels compared with jejunum. Also, viral expression levels in jejunum were higher than in mesenteric lymph nodes. In addition, viral expression levels were not detected in tissues of control cats. The results of the DNA fragmentation assay observed that DNA extracted from different tissues of infected cats exhibited damaged DNA bands as compared with DNA of control cats. DNA fragmentation rates in infected tissues increased significantly (P < 0.01), the highest rates were showed in ilium and jejunum tissue than in mesenteric lymph nodes. Determination of apoptosis in cat tissues showed that rate of apoptosis/necrosis increased significantly (P < 0.05) in infected cats tissues in comparison to control cats. Moreover the highest apoptotic ratios of infected cats were observed in ilium and jejunum tissues compared with mesenteric lymph nodes.