To better understand the ecology and epidemiology of the highly pathogenic avian infl uenza virus in its transcontinental spread, we sequenced and analyzed the complete genomes of 36 recent infl uenza A (H5N1) viruses collected from birds in Europe, northern Africa, and southeastern Asia. These sequences, among the fi rst complete genomes of infl uenza (H5N1) viruses outside Asia, clearly depict the lineages now infecting wild and domestic birds in Europe and Africa and show the relationships among these isolates and other strains affecting both birds and humans. The isolates fall into 3 distinct lineages, 1 of which contains all known non-Asian isolates. This new Euro-African lineage, which was the cause of several recent (2006) fatal human infections in Egypt and Iraq, has been introduced at least 3 times into the European-African region and has split into 3 distinct, independently evolving sublineages. One isolate provides evidence that 2 of these sublineages have recently reassorted.

In the year 2000 an epidemiological research was undertaken on the health status of free-living pigeons in the city of Ljubljana, Slovenia. A total of 139 pigeons were captured and examined for the most common bacterial, viral, and parasitic diseases. Serum samples, oropharyngeal and cloacal swabs as well as samples of droppings and feathers were taken from the captured birds. Antibodies to paramyxovirus type 1 were found in 84.2% of the sera examined, and 23.7% of birds were serologically positive to Chlamydophila psittaci. Antibodies to avian influenza virus were not detected. Salmonella spp. were isolated from 5.7% of the cloacal swabs. Trichomonas gallinae was clinically suspected and then microscopically confirmed using oropharyngeal swabs in 7.9% of examined birds. Eimeria spp. was identified in 71.9%, Capillaria sp. in 26.6% and Ascaridia columbae in 4.3% of droppings samples examined. Of the ectoparasites, Columbicola columbae and Campanulotes bidentatus compar were found.

Maternal antibodies can protect avian embryos against vertically transmitted pathogens during embryogenesis and also young birds after hatching. In contrast to the well-known transfer of maternal immunoglobulin (Ig) G (also termed IgY) from the yolk to embryonic blood, information about the transfer of IgA, IgG and IgM from the egg albumen to the extra-embryonic fluids is very limited. In our study, IgA, IgG and IgM to Mycoplasma gallisepticum and Mycoplasma synoviae were detected in oviduct washings of naturally infected hens and in the corresponding egg albumen samples. In their progeny embryos, IgA, IgG and IgM antibodies to these Mycoplasma species were detected in the allantoic fluid (ALF) and amniotic fluid (AMF) on day 14 of embryonic development (ED). Examination of embryos from chickens immunized with antigens of M. synoviae revealed that the appearance of IgA and IgG and of antibodies to M. synoviae in ALF could vary even among embryos of the same dam. However, IgA, IgG and IgM were detected as early as day 7 of ED in ALF and AMF in certain embryos from hens infected with M. synoviae. In five groups of embryos examined on day 7, IgG to M. synoviae was found in 51% of ALF and 33% of AMF samples. M. synoviae was isolated from 2.3% of ALF samples. IgA to M. synoviae appeared in ALF and AMF on day 12 of ED, and could be found in the majority of AMF samples examined from day 14 onwards. IgM to M. synoviae appeared in AMF on day 13 and in ALF on day 14, but was detected in those fluids less frequently than IgA or IgG.

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Abstract.A rapid and sensitive method for the detection of infectious bursal disease virus (IBDV) RNA in different chicken lymphoid organs was developed. The method is based on a single-step reverse transcription polymerase chain reaction (RT-PCR) procedure and the enzyme-linked immunosorbent assay (ELISA) detection method of amplified products. Vaccinal IBDV strain and field isolates were used for the optimization of RT-PCR and for the determination of conditions for microplate hybridization and colorimetric detection of the amplicons. With this method, viral RNA could be detected in various stages of infection in samples of different lymphoid organs. Bursas and cecal tonsils were suitable organs for viral RNA detection at different times during IBDV infection. The RT-PCR/ELISA method can be applied for IBDV detection in routine diagnostic tests, which are not usually carried out because of the difficulties involved in isolating the virus.Infectious bursal disease (IBD) is a highly contagious viral disease of young chickens that causes significant economic losses in the poultry industry worldwide. 15,16 The clinical disease occurs between 3 and 6 weeks of age. Severe outbreaks are characterized by sudden onset of depression in susceptible flocks. On postmortem examination of birds that died during the acute phase, the bursa of Fabricius is the principal diagnostic organ; it is turgid, edematous, and sometimes hemorrhagic and turns atrophic within 7-10 days. 21 Dehydration and nephrosis with swollen kidneys are common, and hemorrhages in the muscle and mucosa of the proventriculus are observed in the majority of affected birds. 22 The subclinical form of the disease results in immunosupression and increases susceptibility of chickens to other infections. 1 The etiologic agent of IBD is a nonenveloped virus (IBDV) that belongs to the Birnaviridae. 6 Its genome consists of 2 segments of double-stranded RNA. The smaller RNA segment (B) encodes a single 90-kD polypeptide, designated VP1, and the larger RNA segment (A) encodes a viral polyprotein that is processed to form 3 mature proteins, VP2, VP3, and VP4, 2,10 and a small protein, VP5, of unknown function. 17 The published nucleotide sequences of genome segments A and B of various IBDV strains indicate that sequences of the major host-protective immunogen VP2 are highly conserved except in the central hypervariable region, which displays the greatest amount of amino acid sequence variation among strains. 4,7,24 Various methods have been developed for the diagnosis of IBD, such as virus isolation in cell culture, embryonated chicken eggs, or young specific-pathogen-free (SPF) chickens and localization of the virus in infected tissues by electron microscopy, fluorescence assay, agar immunodiffusion, antigene-capture enzyme-linked immunosorbent assay (ELISA), or immunohistochemistry. All these methods have disadvantages, such as being time consuming, labor intensive, expensive, or nonspecific. These methods lack the ability to detect low levels of IBDV antigens in t...