ABSTRACT
The highly pathogenic influenza virus H5N1 that infected chickens in Egypt in 2006 was characterized at immunologic and molecular levels. Cloacal swabs from chicken were analyzed by rapid antigen detection and RT-PCR using H5- and N1-specific primers, which confirmed the presence of an H5N1 influenza virus in infected chickens. Sequencing results revealed 100% homology of both genes with previously published sequences of H5N1 isolates from Egypt and the Middle East. The virus was isolated and propagated in MDBK cells in culture. Host cells showed a substantial cytopathic effect within 2 days of infection, which increased dramatically by the fourth day. Plaque infectivity titers of virus harvested from cell culture were initially 10(5)PFUs/ml and increased to 10(8)PFUs/ml after two additional passages and ultrafiltration. Formaldehyde treatment completely inactivated the virus, and MDBK cells inoculated with the killed virus showed no cytopathic effect. Two days after chickens were immunized with the killed virus, their sera showed that the killed Egyptian isolate was highly immunogenic. Western blot analysis showed that sera had antibodies reacting to four viral peptides: hemagglutinin (61.5kDa), RNA-binding protein (56kDa), neuraminidase (50kDa), and 45-kDa protein. In a challenge infection, the vaccine protected immunized chickens from death and reduced viral shedding.
Subject(s)
Influenza A Virus, H5N1 Subtype/isolation & purification , Influenza in Birds/virology , Poultry Diseases/virology , Animals , Antibodies, Viral/blood , Antibodies, Viral/immunology , Antigens, Viral/analysis , Cattle , Cell Line , Chickens , Cloaca/virology , Cytopathogenic Effect, Viral , Egypt , Influenza Vaccines/immunology , Influenza in Birds/immunology , Influenza in Birds/prevention & control , RNA, Viral/genetics , Sequence Analysis, DNA , Sequence Homology, Nucleic Acid , Viral Plaque AssayABSTRACT
A standardized clinical method for measuring haemoglobin has been applied to measure the quantity of blood ingested by Argas persicus and A. hermanni feeding on chicken and pigeons respectively. The blood fed ticks were added to a reagent which converts all haemoglobin to haemoglobincyanide (HiCN) which can be read spectrophotometrically. The validity of this method was established by comparing haemoglobin determination with the size of blood meals measured by weight. Linear relationships with high correlation coefficients were obtained for nymphs, males, and females of A. persicus and A. hermanni showing that both gravimetric (weighing) and HiCN methods gave similar estimates of ingested blood.
Subject(s)
Blood , Ticks/physiology , Animals , Chickens/parasitology , Feeding Behavior , Female , Hemoglobinometry , Male , Turkeys/parasitologyABSTRACT
Mosquito resting on different host plants were collected from two localities in Egypt, Kafr Tohoria village, Qualubiya governorate and El Abtal village, Ismailia governorate. Collected mosquitoes were identified, classified to their feeding stage and tested for carbohydrate feeding. Results indicated that Cx. pipiens represented 96% and above of collected species in the two localities. The available plants and crops showed different attraction levels for resting female mosquitoes. Most of the collected females were empty. Mosquitoes may be attracted to certain plants due to the presence of some phagostimulant chemicals rather than the presence of the sugars.
