On March 2013, the Libyan poultry industry faced severe outbreaks due to mixed infections of APMV-1 (Newcastle disease) and low pathogenic avian influenza (AI) of the H9N2 subtype which were causing high mortality and great economic losses. APMV-1 and H9N2 were isolated and characterized. Genetic sequencing of the APMV-1/chicken/Libya/13VIR/ 7225-1/2013 isolate revealed the presence of a velogenic APMV-1 belonging to lineage 5 (GRRRQKR*F Lin.5) or genotype VII in class II, according to the nomenclature in use. Three AI viruses of the H9N2 subtype, namely A/avian/Libya/13VIR7225-2/2013, A/avian/Libya/13VIR7225-3/2013, and A/avian/Libya/13VIR7225-5/2013, were isolated and found to belong to the G1 lineage. Analysis of amino acid sequences showed that the analyzed H9N2 viruses contained the amino acid Leu at position 226 (H3 numbering) at the receptor binding site of the HA, responsible for human virus-like receptor specificity. On March 2014, an outbreak of highly pathogenic avian influenza (HPAI) virus of the H5N1 subtype was diagnosed in a backyard poultry farm in an eastern region of Libya. The H5N1 isolate (A/chicken/Libya/14VIR2749-16/2014) was detected by real time RT-PCR (rRT-PCR). Genetic characterization of the HA gene revealed that the identified subtype was highly pathogenic, belonged to the 2.2.1 lineage, and clustered with recent Egyptian viruses. This study revealed the presence of a velogenic APMV-1 genotype and of two influenza subtypes, namely HPAI H5N1 and H9N2, which are of major interest for public and animal health. Considering these findings, more investigations must be undertaken to establish and implement adequate influenza surveillance programs; this would allow better study of the epidemiology of APMV-1 genotype VII in Libya and evaluation of the current vaccination strategies.

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To determine the effect of different doses of Salmonella enteritidis on immunocompetent cells, the thymus, bursa of Fabricius, and peripheral blood were examined. One-day-old chickens were orally infected with 2 × 10 2 CFU/ml (low dose) and 2 × 10 8 CFU/ml (high dose) of S. enteritidis PT4. Subsets of T lymphocytes (CD3, CD4, and CD8), and BU1b cells using an indirect immunofluorescent method and flow cytometry were analysed on days 7, 10, 14, 21, and 27 postinoculation (dpi). The actual number of lymphocytes in the peripheral blood showed a significant increase in the low dose group (P < 0.05) on day 21 pi, and in the high dose group on day 27 pi (P < 0.001) compared to controls. The increase of CD3+, CD4+, and CD8+ T cells was observed in both infected groups compared to the controls from day 14 pi, significant on day 21 pi (P < 0.05) in the high dose group. The subpopulation of CD8+ was higher also on day 27 pi (P < 0.01) compared with the values of the control group. The subpopulation of BU1b+ B cells in both infected groups showed higher values, but without significant differences from controls. The thymus T lymphocytes showed a significant decline in CD3+ T cells on day 7 pi, whereas CD4+ T cells were significantly (P < 0.05) increased on day 7 pi in both infected groups. The bursal lymphocytes showed a decrease in BU1b+ B cells in both infected groups compared with the control group, significant in the high dose group on day 21 pi (P < 0.05). These results indicate that S. enteritidis infection induced the changes in immunocompetent cells, included cellular and humoral immune response. Salmonella infection accelerated the maturation and differentiation of thymus T cells in the first phase of infection, what was secondarily reflected by increased number of studied T lymphocyte subpopulations in the peripheral blood from day 14 to 27 after infection. Similarly, it appears that the activation of B cells in bursa of Fabricius caused the decrease number of bursal B lymphocytes and increased number of these cells in the peripheral blood from day 14 to 27 pi in both infected groups.

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Chicks (1-d-old, three groups, each containing 50 chicks) were inoculated with 2 x 10(2) and 2 x 10(8) CFU of Salmonella enteritidis; the third group were kept as uninoculated control. Five birds from each group were euthanized at intervals from 6 h to 4 weeks post-inoculation (pi). In the low-dose group S. enteritidis was isolated from 60% cecal samples at 18 h pi, and from 20% of livers at 3 d pi. Individual variation in the frequency of S. enteritidis recovery was observed in this group. The clearance of salmonella from the organs was faster in the low-dose group, and salmonella was not isolated from the liver and cecum at 21 and at 27 d pi, respectively. However, in the high-dose group, S. enteritidis was isolated from all ceca and 80% of liver 6 h pi, and salmonella was detected in the cecum and liver throughout the experiment. Serous typhlitis and unabsorbed yolk sac were the most prevalent lesions in both groups. Granulomatous nodules in the cecum were found occasionally in some cases in both inoculated groups, which can play a role as reservoirs in carrier chicks.