Epidemiological surveillance of Newcastle disease virus in Egypt - a 6-year cohort study.

Newcastle disease (ND) is one of the most important poultry diseases worldwide and can lead to annual losses of up to 80% of backyard chickens in Africa. A retrospective cohort of 6 years was planned to screen the NDV in intensive chicken and turkey flocks. The existence of velogenic NDV strain was screened in different poultry flocks showing suspected signs of NDV using real-time RT-PCR targeting the F gene of the velogenic strain. A total of 843 poultry flocks were screened during the cohort. Samples were classified based on the month and year as well as the poultry type. All flocks should be negative for avian influenza virus as an inclusion criterion of the study. The F gene of a randomly selected positive sample from each year as well as an archival sample from 2005 was sequenced. An overall of 52.4% (443/842) of the tested farms showed positive results for the velogenic NDV. The cumulative percentage of positive flocks to the total positive flocks per month ranged from 5.9 to 11.8%. The results revealed that NDV is circulating across all months annually without evidence of seasonal tendency of the disease. Most of the strains belong to genotype VII.1.1, with only two strains related to XXI.1.1 and XXI.2. All VII.1.1 strains possess arginine at 27 position while XXI.1.1 and XXI.2 strains showed cysteine at 27 and amino acid substitutions in the signal peptide, cleavage site, and neutralizing epitopes. In conclusion, the current molecular epidemiological surveillance confirms the enzootic nature of NDV. It circulates all year round with no evidence of seasonal incidence. Genotype VII is the most predominant NDV genotype in Egypt.

Widespread of H5N1 infections in apparently healthy backyard poultry.

Highly pathogenic avian influenza subtype H5N1 represents a threat to the poultry industry and human health worldwide. Inapparently infected birds are suspected to play an essential role in the spread of avian influenza virus. In the current study, a total of 25,646 samples (16,185 chicken, 4696 ducks, 1633 geese and 3132 turkeys) from apparently healthy birds were screened for the presence of positive samples for H5N1 during 2009-2014. The samples were examined by reverse transcriptase real-time polymerase chain reaction (rRT-PCR) for M, H5 and N1 genes of avian influenza viruses. The results revealed that the HPAI H5N1 existed in an inapparent manner in ducks (4.68 %), geese (4.10 %), chickens (2.48 %) and turkeys (2.29 %). The current finding highlights the serious impact of such type on birds in the epidemiology of H5N1 in birds, animals and humans. It also highlights the existence of another reason other than vaccination that contributes to the widespread of inapparent infection of H5N1 in Egypt.