Influenza A Viruses from Wild Birds in Guatemala Belong to the North American Lineage

The role wild bird species play in the transmission and ecology of avian influenza virus (AIV) is well established; however, there are significant gaps in our understanding of the worldwide distribution of these viruses, specifically about the prevalence and/or significance of AIV in Central and South America. As part of an assessment of the ecology of AIV in Guatemala, we conducted active surveillance in wild birds on the Pacific and Atlantic coasts. Cloacal and tracheal swab samples taken from resident and migratory wild birds were collected from February 2007 to January 2010.1913 samples were collected and virus was detected by real time RT-PCR (rRT-PCR) in 28 swab samples from ducks (Anas discors). Virus isolation was attempted for these positive samples, and 15 isolates were obtained from the migratory duck species Blue-winged teal. The subtypes identified included H7N9, H11N2, H3N8, H5N3, H8N4, and H5N4. Phylogenetic analysis of the viral sequences revealed that AIV isolates are highly similar to viruses from the North American lineage suggesting that bird migration dictates the ecology of these viruses in the Guatemalan bird population

Malaria parasites: enzymes involved in red blood cell invasion.

Three enzymes have been described in malaria merozoites: a serine-protease and two phospholipases. The parasite serine-protease is necessary for parasite entry into the red blood cell. This enzyme is synthesized by intraerythrocytic schizonts as a glycolipid-anchored membrane precursor, harbouring a preformed serine-protease active site but no detectable proteolytic activity. Detection of the enzymatic activity correlates with the solubilisation of the enzyme by a parasite glycolipid-specific phospholipase C in merozoites. A third enzyme has been detected with glycolipid-degrading activity, presumably a lipase A. These activities participate in a biochemical cascade originating with the attachment of the merozoite to the red blood cell, including the translocation of the phospholipase C to the membrane-bound protease, the solubilisation/activation of the protease and its secretion at the erythrocyte/parasite junction and ending with the entry of the parasite into the host cell. Both the phospholipase C and the lipase A might generate secondary messages in the merozoite. Our current knowledge concerning these enzymes is presented

Positive species for influenza type A by rRT-PCR and viral isolates obtained in this study.

*<p>Percentage of positive samples obtained by real-time RT-PCR (rRT-PCR) and Virus Isolation (VI) based on the total number of sampled birds.</p><p>N/D: Non-Determined.</p

Genome constellations of AIVs obtained from wild birds in Guatemala.

<p>Nucleotide percent similarities are shown. The different colors represent different clades supported by bootstrap values >70%. *Isolate CIP049-01 was used as reference to estimate sequence percent similarities.</p

Phylogenetic trees for N2 and N8 NA genes.

<p>Trees were generated in PAUP 4.0b10 using Neighbor-Joining method with 1000 bootstrap replicates (bootstrap values above 70% are shown). Scale bar on the bottom-left indicates number of nucleotide substitutions per site.</p

Phylogenetic trees for H3, H8 and H11 HA genes.

<p>Trees were generated in PAUP 4.0b10 using the Neighbor-Joining method with 1000 bootstrap replicates (bootstrap values above 70% are shown). Scale bar on the bottom-left indicates number of nucleotide substitutions per site.</p

Phylogenetic trees for N3, N4, and N9 NA genes.

<p>Trees were generated in PAUP 4.0b10 using the Neighbor-Joining method with 1000 bootstrap replicates (bootstrap values above 70% are shown). Scale bar on the bottom-left indicates number of nucleotide substitutions per site.</p

Phylogenetic trees for internal gene segments PB2, PB1, and PA.

<p>All trees were generated in PAUP 4.0b10 using Neighbor-Joining method with 1000 bootstrap replicates (bootstrap values above 70% are shown). Scale bar on the bottom-left indicates number of nucleotide substitutions per site.</p

Phylogenetic trees for internal gene segments NP, M and NS.

<p>All trees were generated in PAUP 4.0b10 using Neighbor-Joining method with 1000 bootstrap replicates (bootstrap values above 70% are shown). Scale bar on the bottom-left indicates number of nucleotide substitutions per site.</p