ABSTRACT
Background & objectives: Chikungunya (CHIK) is a neglected, re-emerging arboviral disease. Limited information on CHIK-confirmed cases during interepidemic period is available from India. This surveillance study was conducted in Madhya Pradesh (MP), India, during the years 2016-2017, to provide information about CHIK cases. Methods: Blood samples collected from patients suspected having CHIK were tested by immunoglobulin (Ig) IgM ELISA or real time reverse transcription-polymerase chain reaction (rRT-PCR) for the detection of CHIK virus (CHIKV)-specific IgM antibodies or viral RNA, respectively. Partial envelope-1 gene sequencing was done. Clinical and demographic data were collected and analyzed. Results: Of the 4019 samples tested, 494 (12.2%) were found positive for CHIKV infection. The positivity was detected in both rural and urban areas. The mean age of CHIK-positive cases was 33.12�.25 yr. Headache and joint pain were the most prominent symptoms, 34.6 per cent (171/494) of the CHIK cases required hospitalization and six patients with CHIKV infection died. The East/Central/South African genotype of CHIKV was found to be circulating in the study area. Interpretation & conclusions: Our study recorded a higher CHIK positivity during 2016-2017 in comparison to earlier reports from MP, India. A high proportion of CHIK cases required hospitalization and deaths were also reported, which indicated the severity of the disease in the study area. In-depth molecular analysis of the virus and other risk factors is essential to understand the trends in disease severity.
ABSTRACT
Background & objectives: Dengue virus (DENV) causes outbreaks and sporadic cases in tropical and subtropical countries. Documenting intricacies of DEN outbreaks is important for future interventions. The objective of this study was to report clinical, laboratory and epidemiological features of DEN outbreaks reported in different districts of Central India in 2016. Methods: In 2016, outbreaks (n=4) suspected of DEN were investigated by rapid response team. Door-to-door fever and entomological surveys were conducted. Blood samples were collected and tested using NS1 or IgM ELISA; real-time reverse transcription-polymerase chain reaction was done to identify serotypes of DEN virus (DENV). NS1-positive samples were tested for the presence of IgG by ELISA. Clinical and demographic data were collected and analyzed. Results: Outbreaks occurred in both urban and rural areas in monsoon season and Aedes aegypti was identified as the vector. Fever, chills, headache and myalgia were the major symptoms; no fatality was recorded. Of the 268 DEN suspects, 135 (50.4%) were found serologically positive. DEN positivity was higher (n=75; 55.56%) among males and in the age group of 16-45 yr (n=78; 57.8%). DENV 3 followed by DENV 2 were detected as the major responsible serotypes. High attack rates (up to 38/1000) and low cumulative IgG prevalence (14.9%) were recorded in rural areas. Interpretation & conclusions: Our study showed that DENV 3 was the major serotype responsible for outbreaks that occurred in monsoon. High attack rates and lower number of secondary infections in rural areas indicated that DENV is emerging in rural parts of Central India. Early diagnosis at local level and timely intervention by mosquito control activities are needed to avoid such outbreaks in future.