Multicenter, hospital-based surveillance of rotavirus disease and strains among indian children aged <5 years.

BACKGROUND: Current, nationally representative data on rotavirus disease burden and rotavirus strains in India are needed to understand the potential health benefits of rotavirus vaccination. METHODS: The Indian Rotavirus Strain Surveillance Network was established with 4 laboratories and 10 hospitals in 7 different regions of India. At each hospital, children aged <5 years who presented with acute gastroenteritis and required hospitalization with rehydration for at least 6 h were enrolled. A fecal specimen was obtained and was tested for rotavirus with use of a commercial enzyme immunoassay, and strains were characterized using reverse-transcription polymerase chain reaction. RESULTS: From December 2005 through November 2007, rotavirus was found in approximately 39% of 4243 enrolled patients. Rotavirus was markedly seasonal in northern temperate locations but was less seasonal in southern locations with a tropical climate. Rotavirus detection rates were greatest among children aged 6-23 months, and 13.3% of rotavirus infections involved children aged <6 months. The most common types of strains were G2P[4] (25.7% of strains), G1P[8] (22.1%), and G9P[8] (8.5%); G12 strains were seen in combination with types P[4], P[6], and P[8] and together comprised 6.5% of strains. CONCLUSIONS: These data highlight the need for development and implementation of effective prophylactic measures, such as vaccines, to prevent the large burden of rotavirus disease among Indian children.

Diversity of circulating rotavirus strains in children hospitalized with diarrhea in India, 2005-2009.

BACKGROUND: India accounts for 22% of the 453,000 global rotavirus deaths among children <5 years annually. The Indian Rotavirus Strain Surveillance Network provides clinicians and public health partners with valuable rotavirus disease surveillance data. Our analysis offers policy-makers an update on rotavirus disease burden with emphasis on regional shifts in rotavirus strain epidemiology in India. METHODS: Children <5 years requiring hospitalization for acute gastroenteritis were selected from 10 representative hospitals in 7 cities throughout India between November 2005 through June 2009. We used a modified World Health Organization protocol for rotavirus surveillance; stool specimens were collected and tested for rotavirus using enzyme immunoassay and reverse-transcription polymerase chain reaction. RESULTS: A total of 7285 stool specimens collected were tested for rotavirus, among which 2899 (40%) were positive for rotavirus. Among the 2899 rotavirus detections, a G-type could not be determined for 662 (23%) and more than one G type was detected in 240 (8%). Of 1997 (69%) patients with only one G-type, the common types were G1 (25%), G2 (21%), G9 (13%), and G12 (10%). The proportion of rotavirus infections attributed to G12 infections rose from 8% to 39% in the Northern region and from 8% to 24% in the Western region. CONCLUSIONS: This study highlights the large, ongoing burden of rotavirus disease in India, as well as interesting regional shifts in rotavirus strain epidemiology, including an increasing detection of G12 rotavirus strains in some regions. While broad heterotypic protection from rotavirus vaccination is expected based on pre- and post-licensure data from other settings, effectiveness assessments and rotavirus strain monitoring after vaccine introduction will be important.

Critical role of endothelial cell activation in hypoxia-induced vasoocclusion in transgenic sickle mice.

Activation of vascular endothelium plays an essential role in vasoocclusion in sickle cell disease. The anti-inflammatory agents dexamethasone and adhesion molecule-blocking antibodies were used to inhibit endothelial cell activation and hypoxia-induced vasoocclusion. Transgenic sickle mice, expressing human alpha-, beta(S)-, and beta(S-Antilles)-globins, had an activated vascular endothelium in their liver, lungs, and skin, as exhibited by increased activation of NF-kappaB compared with normal mice. NF-kappaB activation increased further in the liver and skin after sickle mice were exposed to hypoxia. Sickle mice had decreases in red blood cell (RBC) velocities and developed vasoocclusions in subcutaneous venules in response to hypoxia. Dexamethasone pretreatment prevented decreases in RBC velocities and inhibited vasoocclusions and leukocyte-endothelium interactions in venules after hypoxia. Dexamethasone treatment inhibited NF-kappaB, VCAM-1, and ICAM-1 expression in the liver, lungs, and skin of sickle mice after hypoxia-reoxygenation. VCAM-1 or ICAM-1 blockade with monoclonal antibodies mimicked dexamethasone by inhibiting vasoocclusion and leukocyte adhesion in sickle mice, demonstrating that endothelial cell activation and VCAM-1 and ICAM-1 expression are necessary for hypoxia-induced vasoocclusion in sickle mice. VCAM-1, ICAM-1, and vasoocclusion increased significantly 3 days after dexamethasone discontinuation, possibly explaining rebounds in vasoocclusive crises observed after withdrawal of glucocorticosteroids in sickle patients. We conclude that anti-inflammatory treatments that inhibit endothelial cell activation and adhesion molecule expression can inhibit vasoocclusion in sickle cell disease. Rebounds in vasoocclusive crises after dexamethasone withdrawal are caused by rebounds in endothelial cell activation.

Microvascular blood flow and stasis in transgenic sickle mice: utility of a dorsal skin fold chamber for intravital microscopy.

Vascular inflammation, secondary to ischemia-reperfusion injury, may play an essential role in vaso-occlusion in sickle cell disease (SCD). To investigate this hypothesis, dorsal skin fold chambers (DSFCs) were implanted on normal and transgenic sickle mice expressing human alpha and beta(s)/beta(s-Antilles) globin chains. Microvessels in the DSFC were visualized by intravital microscopy at baseline in ambient air and after exposure to hypoxia-reoxygenation. The mean venule diameter decreased 9% (P < 0.01) in sickle mice after hypoxia-reoxygenation but remained constant in normal mice. The mean RBC velocity and wall shear rate decreased 55% (P < 0.001) in sickle but not normal mice after hypoxia-reoxygenation. None of the venules in normal mice became static at any time during hypoxia-reoxygenation; however, after 1 hr of hypoxia and 1 hr of reoxygenation, 11.9% of the venules in sickle mice became static (P < 0.001). After 1 hr of hypoxia and 4 hr of reoxygenation, most of the stasis had resolved; only 3.6% of the subcutaneous venules in sickle mice remained static (P = 0.01). All of the venules were flowing again after 24 hr of reoxygenation. Vascular stasis could not be induced in the subcutaneous venules of sickle mice by tumor necrosis factor alpha (TNF-alpha). Leukocyte rolling flux and firm adhesion, manifestations of vascular inflammation, were significantly higher at baseline in sickle mice compared to normal (P < 0.01) and increased 3-fold in sickle (P < 0.01), but not in normal mice, after hypoxia-reoxygenation. Plugs of adherent leukocytes were seen at bifurcations at the beginning of static venules. Misshapen RBCs were also seen in subcutaneous venules.