Protective efficacy of the Newcastle disease virus genotype VII-matched vaccine in commercial layers.

Newcastle disease virus (NDV) is a major threat to the poultry industry worldwide, with a diversity of genotypes associated with severe economic losses in all poultry sectors. Class II genotype VII NDV are predominant in the Middle East and Asia, despite intensive vaccination programs using conventional live and inactivated NDV vaccines. In Egypt, the disease is continuously spreading, causing severe economical losses in the poultry industry. In this study; the protective efficacy of a commercial, inactivated recombinant genotype VII NDV-matched vaccine (KBNP-C4152R2L strain) against challenge with the velogenic NDV strain (Chicken/USC/Egypt/2015) was evaluated in commercial layers. Two vaccination regimes were used; live NDV genotype II (LaSota) vaccine on days 10, 18, and 120, with either the inactivated NDV genotype II regime or inactivated NDV genotype VII-matched vaccine regime on days 14, 42, and 120. The 2 regimes were challenged at the peak of egg production on week 26. Protection by the 2 regimes was evaluated after experimental infection, based on mortality rate, clinical signs, gross lesions, virus shedding, seroconversion, and egg production schedule. The results show that these 2 vaccination regimes protected commercial layer chickens against mortality, but some birds showed mild clinical signs and reduced egg production temporarily. However, the combination of live NDV genotype II and recombinant inactivated genotype VII vaccines provided better protection against virus shedding (20% and 0% vs. 60% and 40%) as assessed in tracheal swabs and (20% and 0% vs. 20% and 20%) in cloacal swabs collected at 3 and 5 D post challenge (dpc), respectively. In addition, egg production levels in birds receiving the inactivated NDV genotype VII-matched vaccine regime and in those given inactivated genotype II vaccines were 76.6, 79, 82, and 87.4% and 77.7, 72.5, 69, and 82.5% at 7, 14, 21, and 28 dpc, respectively. The results of this study indicate that recombinant genotype-matched inactivated vaccine along with a live attenuated vaccine can reduce virus shedding and improve egg production in commercial layers challenged with a velogenic genotype VII virus under field conditions. This regime may ensure a proper control strategy in layers.

Active surveillance for avian influenza virus, Egypt, 2010-2012.

Continuous circulation of influenza A(H5N1) virus among poultry in Egypt has created an epicenter in which the viruses evolve into newer subclades and continue to cause disease in humans. To detect influenza viruses in Egypt, since 2009 we have actively surveyed various regions and poultry production sectors. From August 2010 through January 2013, >11,000 swab samples were collected; 10% were positive by matrix gene reverse transcription PCR. During this period, subtype H9N2 viruses emerged, cocirculated with subtype H5N1 viruses, and frequently co-infected the same avian host. Genetic and antigenic analyses of viruses revealed that influenza A(H5N1) clade 2.2.1 viruses are dominant and that all subtype H9N2 viruses are G1-like. Cocirculation of different subtypes poses concern for potential reassortment. Avian influenza continues to threaten public and animal health in Egypt, and continuous surveillance for avian influenza virus is needed.

Characterization of the recent outbreak of foot-and-mouth disease virus serotype SAT2 in Egypt.

An outbreak of foot-and-mouth disease (FMD) in Egypt affected approximately 40,000 cattle and water buffaloes and killed more than 4,600 animals during February-March 2012. To investigate the etiology of the 2012 outbreak, specimens were collected from six governorates and analyzed using universal primers to amplify the 5' untranslated region (UTR) by reverse-transcription polymerase chain reaction. Only FMDV-SAT2 was detected, with an overall detection rate of 80.3 %. Complete VP1- and leader-proteinase-coding sequences, obtained from three isolates from three different governorates, were compared with previously reported sequences. Phylogenetic analysis of these sequences indicated that the circulating viruses were homogeneous and were closely related to topotype VII. Importantly, the newly emerged viruses were genetically closely related to strains isolated from Saudi Arabia, Sudan, Eritrea and Cameroon between 2000 and 2010, suggesting the dominant nature of this virus and underscoring the need for worldwide intensive surveillance to minimize its devastating consequences.

Antiviral and immune stimulant activities of glycyrrhizin against duck hepatitis virus.

This study was conducted to investigate the effect of glycyrrhizin as an immune stimulant against duck hepatitis virus (DHV). In vitro study was carried out to determine cytotoxic and antiviral effects of glycyrrhizin in VERO cells. In vivo study was performed on 40 one-day-old White Pekin ducklings. -and the birds weres divided into 4 groups: control, glycyrrhizin treated, vaccinated with live attenuated DHV vaccine and glycyrrhizin treated and vaccinated; to investigate the changes in immunity and challenge test. Blood samples were collected from each duckling for evaluation of cellular and humeral immunity. The in vitro results revealed that glycyrrhizin had antiviral and no toxic effects till 106 dilutions. Higher antibody titer was observed from the 5th week till the end of experiment in glycyrrhizin and vaccinated group. Treatment with glycyrrhizin alone or with DHV vaccine demonstrated a pronounced lymphocytic proliferation response after 4 days post-inoculation till the end of experiment, while vaccinated group revealed a pronounced proliferation response after 24 days post-inoculation. Treatment with glycyrrhizin alone or combination with DHV vaccine revealed good immune stimulant and antiviral effect against DHV.

Continuing threat of influenza (H5N1) virus circulation in Egypt.

Reservoirs for the continuing influenza (H5N1) outbreaks in Egypt are ill-defined. Through active surveillance, we detected highly pathogenic influenza subtype H5 viruses in all poultry sectors; incidence was 5%. No other subtypes were found. Continued circulation of influenza (H5N1) viruses in various regions and poultry sectors perpetuates human exposure in Egypt.

Efficacy of volatile oils (curzerene, furanoeudesma-1, 3-diene and lindestrene) on avian coccidiosis under laboratory conditions.

The coccidicidal efficacy of volatile oils (curzerene, furanoeudesma-1, 3-diene and lindestrene) against unsporulated and sporulated chicken Eimeria species oocysts was tested in three concentrations: 1, 2 & 3 microg/ml. Marked reduction in the number of living oocysts was recorded in exposed groups. The concentration of 3 microg/ml volatile oils induced the highest destructive effect. 58.1% of viable unsporulated oocysts were destroyed. A mean number of 153,800 oocysts was the difference between the total number of the produced oocysts per gram faeces in the group infected with exposed oocysts and that of the group infected with non exposed oocysts being less in the exposed group with more reduction in the vitality of shedding oocysts in the former group. At the meantime, the postmortem and histopathological microscopical examination of the intestine and caecum of the tested group revealed a reduction in the intestinal lesions in the group infected with the exposed oocysts.

Efficacy of myrrh in controlling coccidioses in chickens.

Myrrh was used for controlling the infection with Eimeria species in chickens. A total of 120 one-day-old native breed chickens bought from commercial hatchery were used in the experiment. Birds were feed on starter balanced ration free from anticoccidial drugs. At age of 2 weeks the chickens were divided into 4 groups (1-4), 30 chicks each. Chickens of first group were inoculated by 50,000 sporulated oocysts of mixed local field isolated Eimneria species and served as infected non treated control group. Birds of the second group were infected similarly and received simultaneously 10 mg Myrrh / bird by oral route. Birds of group 3 was supplied with Myrrh 10 mg / bird one day before infection by coccidia (50000 oocyst/bird). Last chicken group was left as non infected non treated control group. Measurements to evaluate the efficacy of Myrrh as anticoccidial drug included; mortality percentage; lesion score at 5 day post infection and the total oocyst output/gm of fecal dropping. The results showed that the mortality rate reached 10% and 3.33% in groups 2&3 respectively, while it reached 26.66% in infected non treated control group. High lesion score was recorded in infected non treated group followed by infected treated chicken groups regardless the time of treatment. The feed conversion rates reached 3.14 in infected non treated chicken group against 2.47 & 2.21 in treated chickens groups, 2&3 respectively. Mean oocyst count per gram faecal dropping (OPG) was reduced significantly in group 3 when compared with other infected treated or infected non treated chicken groups.