Akhilesh C. Mishra

Nipah Virus-associated Encephalitis Outbreak, Siliguri, India

Nipah virus, not previously detected in India, caused an outbreak of febrile encephalitis in West Bengal.

Chikungunya outbreaks caused by African genotype, India.

Chikungunya fever is reported in India after 32 years. Immunoglobulin M antibodies and virus isolation confirmed the cause. Phylogenic analysis based on partial sequences of NS4 and E1 genes showed that all earlier isolates (1963–1973) were Asian genotype, whereas the current and Yawat (2000) isolates were African genotype.

Prevalence of anti-hepatitis E virus antibodies in different Indian animal species

Prevalence of IgG antibodies to hepatitis E virus (IgG‐anti‐HEV) was determined among different animal species from India. Seropositivity varied from 4.4% to 6.9% in cattle, 54.6–74.4% in pigs and 2.1–21.5% in rodents. Of the 44 dogs screened, 10 were positive (22.7%). None of the 250 goat sera tested were found to be anti‐HEV positive. Among rodents, over 50% serum samples collected in 1985 from Bandicota bengalensis were positive for anti‐HEV antibodies. No evidence of HEV infection was obtained following experimental inoculation of an Indian strain (AKL‐90) of HEV into anti‐HEV negative pigs and goats. The results document varied prevalence of anti‐HEV antibodies in different animal species from India and of inability of Indian pigs and goats to support replication of at least one human strain of HEV.

Systemic involvements and fatalities during Chikungunya epidemic in India, 2006.

BACKGROUND In addition to classical manifestations of Chikungunya infection, severe infections requiring hospitalization were reported during outbreaks in India in 2006. OBJECTIVES To describe the systemic syndromes and risk groups of severe Chikungunya infections. STUDY DESIGN We prospectively investigated suspected Chikungunya cases hospitalized in Ahmedabad, Gujarat during September-October 2006, and retrospectively investigated laboratory-confirmed Chikungunya cases hospitalized with neurologic syndromes in Pune, Maharashtra. Hospital records were reviewed for demographic, comorbidity, clinical and laboratory information. Sera and/or cerebrospinal fluid were screened by one or more methods, including virus-specific IgM antibodies, viral RNA and virus isolation. RESULTS Among 90 laboratory-confirmed Chikungunya cases hospitalized in Ahmedabad, classical Chikungunya was noted in 25 cases and severe Chikungunya was noted in 65 cases, including non-neurologic (25) and neurologic (40) manifestations. Non-neurologic systemic syndromes in the 65 severe Chikungunya cases included renal (45), hepatic (23), respiratory (21), cardiac (10), and hematologic manifestations (8). Males (50) and those aged >or=60 years (50) were commonly affected with severe Chikungunya, and age >or=60 years represented a significant risk. Comorbidities were seen in 21 cases with multiple comorbidities in 7 cases. Among 18 deaths, 14 were males, 15 were aged >or=60 years and 5 had comorbidities. In Pune, 59 laboratory-confirmed Chikungunya cases with neurologic syndromes were investigated. Neurologic syndromes in 99 cases from Ahmedabad and Pune included encephalitis (57), encephalopathy (42), and myelopathy (14) or myeloneuropathy (12). CONCLUSIONS Chikungunya infection can cause systemic complications and probably deaths, especially in elderly adults.

Genetic Characterization of the Influenza A Pandemic (H1N1) 2009 Virus Isolates from India

Background The Influenza A pandemic H1N1 2009 (H1N1pdm) virus appeared in India in May 2009 and thereafter outbreaks with considerable morbidity and mortality have been reported from many parts of the country. Continuous monitoring of the genetic makeup of the virus is essential to understand its evolution within the country in relation to global diversification and to track the mutations that may affect the behavior of the virus. Methods H1N1pdm viruses were isolated from both recovered and fatal cases representing major cities and sequenced. Phylogenetic analyses of six concatenated whole genomes and the hemagglutinin (HA) gene of seven more isolates from May-September 2009 was performed with reference to 685 whole genomes of global isolates available as of November 24, 2009. Molecular characterization of all the 8 segments was carried out for known pathogenic markers. Results The first isolate of May 2009 belonged to clade 5. Although clade 7 was the dominant H1N1pdm lineage in India, both clades 6 and 7 were found to be co-circulating. The neuraminidase of all the Indian isolates possessed H275, the marker for sensitivity to the neuraminidase inhibitor Oseltamivir. Some of the mutations in HA are at or in the vicinity of antigenic sites and may therefore be of possible antigenic significance. Among these a D222G mutation in the HA receptor binding domain was found in two of the eight Indian isolates obtained from fatal cases. Conclusions The majority of the 13 Indian isolates grouped in the globally most widely circulating H1N1pdm clade 7. Further, correlations of the mutations specific to clade 7 Indian isolates to viral fitness and adaptability in the country remains to be understood. The D222G mutation in HA from isolates of fatal cases needs to be studied for pathogenicity.

Global Distribution of Novel Rhinovirus Genotype

Global surveillance for a novel rhinovirus genotype indicated its association with community outbreaks and pediatric respiratory disease in Africa, Asia, Australia, Europe, and North America. Molecular dating indicates that these viruses have been circulating for at least 250 years.

Enteroviruses in Patients with Acute Encephalitis, Uttar Pradesh, India

An outbreak of viral encephalitis occurred in northern India in 2006. Attempts to identify an etiologic agent in cerebrospinal fluid by using reverse transcription–PCR showed positivity to enterovirus (EV) in 66 (21.6%) of 306 patients. Sequencing and phylogenetic analyses of PCR products from 59 (89.3%) of 66 specimens showed similarity with EV-89 and EV-76 sequences.

Influenza seasonality and vaccination timing in tropical and subtropical areas of southern and south-eastern Asia

OBJECTIVE To characterize influenza seasonality and identify the best time of the year for vaccination against influenza in tropical and subtropical countries of southern and south-eastern Asia that lie north of the equator. METHODS Weekly influenza surveillance data for 2006 to 2011 were obtained from Bangladesh, Cambodia, India, Indonesia, the Lao Peoples Democratic Republic, Malaysia, the Philippines, Singapore, Thailand and Viet Nam. Weekly rates of influenza activity were based on the percentage of all nasopharyngeal samples collected during the year that tested positive for influenza virus or viral nucleic acid on any given week. Monthly positivity rates were then calculated to define annual peaks of influenza activity in each country and across countries. FINDINGS Influenza activity peaked between June/July and October in seven countries, three of which showed a second peak in December to February. Countries closer to the equator had year-round circulation without discrete peaks. Viral types and subtypes varied from year to year but not across countries in a given year. The cumulative proportion of specimens that tested positive from June to November was > 60% in Bangladesh, Cambodia, India, the Lao Peoples Democratic Republic, the Philippines, Thailand and Viet Nam. Thus, these tropical and subtropical countries exhibited earlier influenza activity peaks than temperate climate countries north of the equator. CONCLUSION Most southern and south-eastern Asian countries lying north of the equator should consider vaccinating against influenza from April to June; countries near the equator without a distinct peak in influenza activity can base vaccination timing on local factors.

Genomic Characterization of Nipah Virus, West Bengal, India

An intrafamilial outbreak in West Bengal, India, involving 5 deaths and person-to-person transmission was attributed to Nipah virus. Full-genome sequence of Nipah virus (18,252 nt) amplified from lung tissue showed 99.2% nt and 99.8% aa identity with the Bangladesh-2004 isolate, suggesting a common source of the virus.

Pandemic Influenza (H1N1) 2009 Is Associated with Severe Disease in India

Background Pandemic influenza A (H1N1) 2009 has posed a serious public health challenge world-wide. In absence of reliable information on severity of the disease, the nations are unable to decide on the appropriate response against this disease. Methods Based on the results of laboratory investigations, attendance in outpatient department, hospital admissions and mortality from the cases of influenza like illness from 1 August to 31 October 2009 in Pune urban agglomeration, risk of hospitalization and case fatality ratio were assessed to determine the severity of pandemic H1N1 and seasonal influenza-A infections. Results Prevalence of pandemic H1N1 as well as seasonal-A cases were high in Pune urban agglomeration during the study period. The cases positive for pandemic H1N1 virus had significantly higher risk of hospitalization than those positive for seasonal influenza-A viruses (OR: 1.7). Of 93 influenza related deaths, 57 and 8 deaths from Pune (urban) and 27 and 1 death from Pune (rural) were from pandemic H1N1 positive and seasonal-A positive cases respectively. The case fatality ratio 0.86% for pandemic H1N1 was significantly higher than that of seasonal-A (0.13%) and it was in category 3 of the pandemic severity index of CDC, USA. The data on the cumulative fatality of rural and urban Pune revealed that with time the epidemic is spreading to rural areas. Conclusions The severity of the H1N1 influenza pandemic is less than that reported for ‘Spanish flu 1918’ but higher than other pandemics of the 20th century. Thus, pandemic influenza should be considered as serious health threat and unprecedented global response seems justified.