Detection of dengue-4 virus in pune, western india after an absence of 30 years - its association with two severe cases

Abstract

BackgroundDifference in severity of dengue outbreaks has been related to virus serotype, genotype and clades within genotypes. Till the 1980 s, India and Sri Lanka reported low number of dengue hemorrhagic fever (DHF) cases despite circulation of all four serotypes of dengue virus (DENV). Since the 1990 s the occurrence of DHF has increased. The increase has been attributed to changes in virus lineage especially with regard to DENV-2 and DENV-3. DENV-1 has been associated with dengue fever (DF) outbreaks and DENV-4 reports have been rare. The emergence of DENV-4 was reported recently in 2003 in Delhi and in 2007 in Hyderabad. The last report of DENV-4 from Maharashtra was in 1975 from Amalner.ResultsWe report on the detection of DENV-4 in Pune, Maharashtra after an absence of almost 30 years. Two cases were detected in 2009-10, serotyped by multiplex reverse transcriptase polymerase chain reaction (RT-PCR). Both the cases were recorded as severe dengue (Category 3) requiring intensive care unit (ICU) level of treatment. Depending on the hemagglutination inhibiting (HI) antibody titres the 2009 case was characterized as a primary infection and the 2010 case as a secondary infection. Both the cases presented plasma leakage and neither showed any kind of haemorrhage. The 2009 case survived while the 2010 case was fatal. An isolate was obtained from the 2009 case. Based on envelope (E) gene sequence analysis, the virus belonged to genotype I of DENV-4, and clustered with isolates from India and Sri Lanka and was distant from the isolates from Thailand. The nucleotide and amino acid diversity of the E gene of the Indian isolates increased from 1996 to 2007 to 2009 in context of the E gene sequences of other isolates belonging to genotype I.ConclusionThe increasing diversity in the circulating DENV-4 calls for close monitoring of the DENV-4 serotype.

The Clinical, Serological and Molecular Diagnosis of Emerging Dengue Infection at a Tertiary Care Institute in Southern, India

“…42% of the cases with the DENV-4 infection needed hospitalization and all of them were managed conservatively without an intensive care treatment. This was in contrast to the findings of the study which was done by Cecilia et al, [20] where both the DENV-4 cases needed intensive care treatment and one case had expired. All the cases with DENV-4 in our study were clinically diagnosed with Dengue fever and they were managed conservatively; no mortality was recorded among them.…”

A Comprehensive Study on the 2012 Dengue Fever Outbreak in Kolkata, India

“…An attempt was also made to identify the circulating serotypes of dengue virus in the city of Kolkata. Six, acute serum samples (duration of fever < than 4 days), collected immediately after the onset of the dengue fever outbreak, were transferred to the referral Virology Laboratory of Maulana Azad Medical College, New Delhi, maintaining cold Aug. 8-Aug. 14 Aug. 15 chain. The identified serotypes were Den1 in 3 samples (two female patients, 16 and 46 years of age, and one male patient of age 13 years), Den3 in 2 samples (two male patients of age 18 and 15 years), and Den4 in one sample from an 18-year female patient.…”

“…The samples were screened for the presence of dengue-specific IgM antibodies by IgM antibody capture enzyme-linked immunosorbent assay (MAC-ELISA): using a kit prepared by the National Institute of Virology, Pune, India (as an integral part of the National Vector Borne Disease Control Programme), strictly following the manufacturer's protocol [15].…”

Genetic characterization of dengue viruses prevalent in Kerala State, India

“…5). This rare serotype in India was reported recently from Maharashtra (Cecilia et al, 2011) and Andhra Pradesh (Dash et al, 2011). The disease caused by this serotype was described to be severe (grade III) in the first study: one case, which was a primary infection survived, whilst another with a secondary infection died.…”