Circulation of Asian-I and Cosmopolitan genotypes of Dengue-2 virus in northeast India, 2016-2017.

BACKGROUND & OBJECTIVES: Dengue is a major public health problem in northeast India where the majority of the cases go unreported and undiagnosed. Even though all four dengue serotypes are reported, there is a dearth of information on genetic diversity. The present cross-sectional study was undertaken during 2016-17 to determine the genetic variance of dengue virus serotype 2 (DENV-2) based on the envelope (E) glycoprotein gene. METHODS: The serum samples collected from the northeast parts of India, as a part of hospital-based acute febrile illness surveillance, were serotyped. Viral RNA was extracted from DENV-2 serum samples using QIAquick® RNA Extraction Kit. The E gene was amplified by conventional reverse-transcriptase polymerase chain reaction (RT-PCR) and the PCR products were sequenced. RESULTS: The E glycoprotein gene of nine serum samples with high viral RNA concentration (Ct <25) was sequenced. The E gene sequences of eight DENV-2 strains from Assam and Meghalaya aligned with genotype IV (Cosmopolitan) and one strain from Tripura segregated with Asian-I genotype. INTERPRETATION & CONCLUSION: Ongoing laboratory-based surveillance is mandatory to understand the transmission dynamics of dengue in endemic countries. This study concluded that in northeast India, presently two distinct genotypes of DENV-2, namely genotype IVb (Cosmopolitan) and Asian-I genotype are in circulation.

Genotyping of human adenoviruses circulating in Southwest India.

Adenoviruses are found to be associated with a wide range of diseases in children and adults. There is little data available on the circulating serotypes of Human Adenoviruses (HAdVs) in the southwest region of India. In this study, we explore the molecular epidemiology of HAdVs circulating in southwest India. Twenty-three samples (Adenovirus PCR positive), collected between January 2011 and March 2013, have been typed based on the partial hexon gene sequence and phylogenetic analysis. The commonest serotypes were HAdV-3 and HAdV-2. The other serotypes were HAdV-7, HAdV-1, HAdV-8 and HAdV-40. Respiratory illness was the most common clinical manifestation of HAdV-3, HAdV-2 and HAdV-7 serotypes. HAdV-3, HAdV-7 and HAdV-8 were found to cause conjunctivitis, whereas HAdV-1, HAdV-2 and HAdV-3 caused encephalitis. In conclusion, this study documents the circulating HAdV strains and the epidemiology in southwest India. To the best of our knowledge, this is the first study on the molecular epidemiology of HAdVs in India.

Drug-induced hypersensitivity syndrome with human herpesvirus-6 reactivation.

A 45-year-old man, on carbamazepine for the past 3 months, was referred as a case of atypical measles. On examination, he had high-grade fever, generalized itchy rash, cough, vomiting and jaundice. A provisional diagnosis of drug hypersensitivity syndrome to carbamazepine was made with a differential diagnosis of viral exanthema with systemic complications. Laboratory investigations revealed leukocytosis with eosnophilia and elevated liver enzymes. Real-time multiplex polymerase chain reaction (PCR) on throat swab and blood was suggestive of human herpesvirus-6 (HHV-6). Measles was ruled out by PCR and serology. The diagnosis of drug-induced hypersensitivity syndrome (DIHS) was confirmed, which could explain all the features manifested by the patient. HHV-6 infects almost all humans by age 2 years. It infects and replicates in CD4 T lymphocytes and establishes latency in human peripheral blood monocytes or macrophages and early bone marrow progenitors. In DIHS, allergic reaction to the causative drug stimulates T cells, which leads to reactivation of the herpesvirus genome. DIHS is treated by withdrawal of the culprit drug and administration of systemic steroids. Our patient responded well to steroids and HHV-6 was negative on repeat real-time multiplex PCR at the end of treatment.