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Chikungunya fever is a major public health issue in India affecting billions. After 2010, the infection was in a decline until in 2016, when a massive outbreak affected the country. In this report, we present serologic and molecular investigations of 600 patient samples for chikungunya and dengue viruses along with clinical and comorbidity features. We recruited 600 patients during this outbreak and evaluated them for chikungunya and dengue virus antibodies and virus RNA through IgM, NS1 antigen and quantitative real-time PCR (qPCR). We further evaluated Zika virus RNA by qPCR. Additionally, we documented all clinical and comorbid features that were observed during the outbreak in the hospital. We report a total incidence rate of 58% of chikungunya during the outbreak in our hospital. Within the recruited patients, 70% of the patients were positive for chikungunya virus IgM whereas 24.17% were positive by qPCR. None of the samples was positive for Zika virus RNA. Additionally, coinfection of dengue and chikungunya was seen in 25.33% of patients. Analysis of clinical features revealed that 97% of patients had restricted movements of the joints with other features like swelling, itching and rashes of varying severity observed. Twelve patients presented with comorbid conditions, and two fatalities occurred among these comorbid patients. The high incidence of coinfection in the current outbreak warrants implementation of routine testing of both chikungunya and dengue virus in suspected patients for better patient management. The post–acute phase complications reported in the hospitals require in-depth studies to understand the actual impact of the current outbreak.

The prevalence of functional asplenia in Omani children with sickle cell disease (SCD) has not been previously defined. In this study, the authors aim to compare the natural history of splenic dysfunction in their patients to other reports. The splenic function was studied in 72 Omani patients with sickle cell disease (50 homozygous for hemoglobin S (HbS-S), 11 double heterozygotes for HbS and beta(0)-thalassemia (HbS-beta(0)-thal), 5 HbS-beta(+)-thal, 5 patients with hemoglobin S-D disease, and 1 child with hemoglobin S oman trait) aged 4.8-16 years, using (99m)Tc-labeled tin colloid scintigraphy. The study revealed 4 groups according to their colloid uptake: group I included 20 patients (28%) with normal splenic function; group II, 6 patients (8%) with mild hyposplenism; group III, 20 (28%) with severe hyposplenism; and group IV, 26 (36%) patients with functional asplenia. Overall, more than 60% of them had preserved splenic function. Except for HbS-beta(+) patients, the developmental pattern of hyposplenism was not different among the different Hb phenotypes. Factors associated with preservation of spleen function in these patients were larger splenic size (p < .01), less clinical severity (p < .05), lower MCH (p < .01), higher HbF (p < .001), and presence of alpha-thalassemia trait (p < .05).

Chikungunya fever (CHIKF) is a major public health concern and is caused by chikungunya virus (CHIKV). In 2005, the virus was reintroduced into India, resulting in massive outbreaks in several parts of the country. During 2010 and 2016 outbreaks, we recruited 588 patients from a tertiary care hospital in New Delhi, India, during the acute phase of CHIKF; collected their blood and clinical data; and determined their arthralgic status 12 weeks post-onset of fever. We evaluated IgM/IgG CHIKV-binding antibodies and their neutralizing capacity, sequenced complete genomes of 21 CHIKV strains, and correlated mutations with patient sequelae status. We also performed infections in murine models using representative strains from each outbreak to evaluate differences in pathogenesis. Our screening and analysis revealed that patients of the 2016 outbreak developed earlier IgM and neutralizing antibody responses that were negatively correlated with sequelae, compared with 2010 patients. Mutations that correlated with human disease progression were also correlated with enhanced murine virulence and pathogenesis. Overall, our study suggests that the development of early neutralizing antibodies and sequence variation in clinical isolates are predictors of human sequelae.

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