Seropositivity and seasonal trend of dengue cases in Jaipur (Rajasthan), Western India (2010-2016)
Abstract
Dengue virus infection has emerged as a notable public health problem in recent decades in terms of its increased transmission to urban and semi urban areas. Study was conducted on samples of suspected dengue cases with the aim to find out seropositivity and seasonal pattern of dengue, which is important for effective control of a disease. For this study, samples were received in department of Microbiology, SMS Hospital Jaipur (Rajasthan) for Dengue IgM & IgG during 1st January 2010 to 31st December 2016. Blood samples collected in plain vials were tested for IgM and IgG antibodies for dengue virus serotype DENV-1, 2, 3 and 4 by a solid phase in vitro immunochromatographic test. It was observed that out of 86,538 serum samples tested, 5011 (5.76 %) were found to be positive for dengue infection. Among these seven years, maximum numbers of dengue cases were identified in year 2013(33.12%). Seropositivity ranged from 0.73% in year 2016 to 13.1% in year 2010. Likewise when seasonal trend was explored it was found that 83.87% of total cases were found from September to November with peak in October. In rest of months around 1% of cases were there in each month except few more cases in August and December i.e. 4.23% and 6.25% respectively. It can be concluded that Dengue has become an endemic disease in this area. Occurrence of most of the cases in post-monsoon period indicates a need for acceleration of vector control programme prior to monsoon.
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Introduction
Dengue an important arthropod – borne viral infection, has become a major public health concern. It is spreading to new geographical areas, with a 30-fold increase in global incidence over the past 50 years.1 Each year, 50-100 million cases occur worldwide and hospitalizations for the infection have reached 5,00,000 and the global death toll is >20,000 persons.1 As per WHO criteria for dengue endemicity in South-East Asia region, India falls into Risk category 'A' i.e. high endemic area.
The first epidemic of clinical dengue-like illness was recorded in Chennai (1780), dengue fever (DF) in Kolkata, India (1963-1964) and dengue hemorrhagic fever (DHF) in Philippines (1953-54). 2 Dengue cases were subsequently reported from Kolkata (1963), Vishkapattanam (1964), Vellore (1968), Ajmer (1969), Kanpur (1969), Jalore of Rajasthan (1985), Chandigarh (2002), Mumbai (2004), Ludhiana (2007), New Delhi (1996, 2003, 2006, 2010), Chennai (2006-2008), Kerala (2008) and Odisha State in 2010.3-5 Recurring outbreaks of DF/DHF were also reported in the years 2005–2008 from other states like Andhra Pradesh, Goa, Haryana, Gujarat, Karnataka, Uttar Pradesh, Pondicherry and West Bengal . 5
Conclusion
This study concludes that dengue is a rapidly expanding disease in this part of the country. Seropositivity was found 5.79% with a set seasonal trend having maximum cases in September to November. It is useful to predict outbreak and thus initiation of early control measures. It is suggested that vector control measures should be integrated with vaccines in monsoon months (June to September) well in advance before the peak of dengue in October.