Clinical and molecular observations of two fatal cases of rotavirus-associated enteritis in children in Italy

Abstract

Two fatal cases of infantile rotavirus enteritis occurred in northern Italy in 2005. Both children were severely dehydrated, and death was related to severe cerebral edema. Histological examination demonstrated extensive damage of the intestinal epithelium, villous atrophy or blunting, and macrophage infiltration. The two rotavirus strains were of the G1P[8] type and the long electropherotype. The 2005 G1P[8] rotaviruses differed in the NSP4, VP3, VP4, and VP7 genes from G1P[8] rotaviruses circulating in 2004, suggesting the onset of a new G1P[8] strain in the local population.

Fig. 1

(A) Low-power histopathological view of the small bowel wall with marked inflammatory infiltration involving the lamina propria and diffuse villous disepithelization (arrow). Hematoxylin-eosin staining is shown; original magnification, ×4. (B) The villi are often blunted and sometimes fused. In addition to being disepithelized, they show a severe lymphoplasmacytic and granulocytic infiltration of the lamina propria. Hematoxylin-eosin staining is shown; original magnification, ×20. (C) Ileal portion with complete loss of intestinal villi. Hematoxylin-eosin staining is shown; original magnification, ×4. (D) High-power histopathological view of the colonic mucosa with mild-to-moderate lymphoplasmacytic and granulocytic infiltration involving the lamina propria. Hematoxylin-eosin staining is shown; original magnification, ×20.

Fig. 2

Neighbor-joining phylogenetic trees based on the deduced NSP4 amino acid sequences corresponding to aa 4 to 175 (corresponding to reference strain Wa, accession no. K02032) (p-distance model) (A), nucleotides 85 to 1011 (corresponding to reference strain Wa, accession no. M96825) of the VP4 gene (Kimura 2-parameter model) (B), nucleotides 127 to 995 (corresponding to reference strain Wa, accession no. K02033) (Kimura 2-parameter model) of the VP7 gene (C), and nucleotides 735 to 880 (corresponding to reference strain Wa, accession no. AY267335) (Kimura 2-parameter model) of the VP3 gene (D) of group A rotaviruses found in northern Italy in 2004 and 2005, including 2 strains detected in two fatal cases of rotavirus enteritis (PR1598/2005/F and PR1609/2005/F), and of group A rotaviruses from GenBank. The GenBank nucleotide sequence accession numbers are shown in parentheses. Percentage bootstrap values (of 1,000 replicates) above 80% are shown at the branch nodes. The scale bar in each panel indicates the number of nucleotide substitutions per position. The NSP4 genogroups (A), as well as P[8] (B) and G1 (C) lineages, are indicated by the brackets to the right of the dendrograms.

Fig. 3

Schematic representations of NSP4 secondary structure predictions obtained with the PSIPRED protein structure prediction server. The panel depicts aa 124 to 175. (Boxes a) Beginning at aa 141 (PR1533/2004 strain) or 142 (PR2108/2004 and PR1494/2004 strains), the 2-aa β-sheet of the 2004 strains has mutated into a 3-aa β-sheet in the PR1598/2005/F strain. (Boxes b) Beginning at aa 146, the 8- and 5-aa α-helices of the PR2108/2004 strain have mutated into a 15-aa α-helix in the PR1598/2005/F strain. Conf, confirmed; Pred, predicted; AA, amino acid.

Fig. 4

Schematic representations of VP8* secondary structure predictions obtained with the PSIPRED protein structure prediction server. Shown are aa 26 to 334. Boxes a to k highlight differences in the predicted protein secondary structure of 2005 strain PR1598/2005/F with respect to 2004 strains PR1533/2004 and PR2108/2004. Conf, confirmed; Pred, predicted; AA, amino acids.