Subrat Kumar

Hepatitis E virus: the current scenario

Hepatitis E infection, caused by the hepatitis E virus (HEV), is a common cause of acute hepatitis in developing countries with poor sanitation and hygiene. The virus is classified into four genotypes (1-4) with one serotype. Genotypes 1 and 2 exclusively infect humans, whereas genotypes 3 and 4 also infect other animals, particularly pigs. In endemic areas, large outbreaks of acute hepatitis caused by viruses of genotype 1 or 2 frequently occur due to fecal-oral transmission, usually through contamination of drinking water. With a high attack rate in young adults (aged 15-45 years), the disease is particularly severe among pregnant women (20-30% mortality). HEV appears to be a zoonotic disease, with transmission from pigs, wild boars, and deer, or foodborne. Chronic infections are rare, except in immunosuppressed persons, such as organ transplant recipients. A subunit vaccine has been shown to be effective in preventing the clinical disease, but is not yet commercially available. Our understanding of HEV has undergone major changes in recent years and in this article we review the currently available information with regard to the molecular biology, pathobiology, and epidemiology of HEV infection. We also review the current therapeutic interventions and strategies being used to control HEV infection, with emphasis on possible approaches that could be used to develop an effective vaccine against HEV.

Human metapneumovirus: review of an important respiratory pathogen

Summary Human metapneumovirus (hMPV), discovered in 2001, most commonly causes upper and lower respiratory tract infections in young children, but is also a concern for elderly subjects and immune-compromised patients. hMPV is the major etiological agent responsible for about 5% to 10% of hospitalizations of children suffering from acute respiratory tract infections. hMPV infection can cause severe bronchiolitis and pneumonia in children, and its symptoms are indistinguishable from those caused by human respiratory syncytial virus. Initial infection with hMPV usually occurs during early childhood, but re-infections are common throughout life. Due to the slow growth of the virus in cell culture, molecular methods (such as reverse transcriptase PCR (RT-PCR)) are the preferred diagnostic modality for detecting hMPV. A few vaccine candidates have been shown to be effective in preventing clinical disease, but none are yet commercially available. Our understanding of hMPV has undergone major changes in recent years and in this article we will review the currently available information on the molecular biology and epidemiology of hMPV. We will also review the current therapeutic interventions and strategies being used to control hMPV infection, with an emphasis on possible approaches that could be used to develop an effective vaccine against hMPV.

Outbreak of avian influenza virus H5N1 in India

SIR, — The highly pathogenic avian influenza (hpai) virus subtype h5n1 has become endemic in poultry populations in south-east Asia since 2003. During the second week of July 2007, an unusual mortality of 82 per cent was reported in a flock of 132 chickens on a poultry farm in Manipur, northeast

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Molecular detection and sequence analysis of hepatitis E virus in patients with viral hepatitis from North India.

Viral hepatitis is a major cause of mortality and morbidity in developing countries. Hepatitis E virus (HEV) is responsible for both sporadic and epidemic outbreaks of viral hepatitis in India. Here a total of 843 samples were collected: 685 from patients with acute viral hepatitis (AVH), 70 from patients with fulminant hepatic failure (FHF), 53 from patients with chronic liver disease (CLD), 11 from patients with antituberculosis therapy (ATT)-induced jaundice, and 24 from pregnant women. When tested for anti-HEV IgM, 58.3% of the pregnant women, 41.4% of the patients with FHF, 38.6% of the patients with AVH, 9.4% of the patients with CLD, and 18.2% of the patients with ATT-induced jaundice tested positive. We found that 34% and 16% of the acute hepatitis patients and fulminant hepatitis patients, respectively, showed no reactivity to the existing viral hepatitis markers and were thus grouped as non A to E. Among the HEV IgM-positive cases, males outnumbered females (62.8% versus 37.1%). HEV RNA was found in 35% of fulminant and 9.4% of acute hepatitis patients. From phylogenetic analysis, we observed that all the isolates were clustered within genotype 1. Critical analysis placed the acute isolates along with strains under subtype Ia, while the fulminant isolates clustered along with the FHF strain (X98292) under subtype Ic. The segregation of HEV isolates from AVH and FHF patients into different subtypes raises interesting questions on the molecular basis of HEV disease severity.

Phylogenetic analysis and subtyping of acute and fulminant strains of hepatitis E virus isolates of North India with reference to disease severity

Hepatitis E is endemic to the Indian subcontinent, with a seroprevalence of 4–20%, and more than 25% of acute viral hepatitis is due to HEV. The northern parts of India have been experiencing outbreaks and sporadic cases of HEV since 1955. In a total of sixteen HEV sequences, ten acute viral hepatitis and 6 fulminant hepatic failure cases were analysed. Subtypes 1a and 1c of HEV are prevalent in North India, with the subtype-1c showing a trend towards fulminancy.

Revisiting the global problem of cryptosporidiosis and recommendations

Cryptosporidiosis is a gastrointestinal illness caused by the protozoan parasite Cryptosporidium species, which is a leading cause of diarrhea in a variety of vertebrate hosts. The primary mode of transmission is through oral routes; infections spread with the ingestion of oocysts by susceptible animals or humans. In humans, Cryptosporidium infections are commonly found in children and immunocompromised individuals. The small intestine is the most common primary site of infection in humans while extraintestinal cryptosporidiosis occurs in immunocompromised individuals affecting the biliary tract, lungs, or pancreas. Both innate and adaptive immune responses play a critical role in parasite clearance as evident from studies with experimental infection in mice. However, the cellular immune responses induced during human infections are poorly understood. In this article, we review the currently available information with regard to epidemiology, diagnosis, therapeutic interventions, and strategies being used to control cryptosporidiosis infection. Since cryptosporidiosis may spread through zoonotic mode, we emphasis on more epidemiological surveillance-based studies in developing countries with poor sanitation and hygiene. These epidemiological surveys must incorporate fecal source tracking measures to identify animal and human populations contributing significantly to the fecal burden in the community, as mitigation measures differ by host type.

Etiology, seasonality, and clinical characteristics of respiratory viruses in children with respiratory tract infections in Eastern India (Bhubaneswar, Odisha).

Acute respiratory tract infections (ARTIs) are a leading cause of morbidity and mortality in young children in low and middle income countries. To analyse the overall burden of respiratory viruses responsible for ARTIs in paediatrics population in eastern India, this study was performed. Clinical information, demographic information and nasal/oral swabs were collected from 332 paediatric patients (aged from 1 month to 12 years old) with the symptoms of ARTI, enrolled from the outpatient department from Nov 2012 to Oct 2014. Multiplex PCR was performed to detect eight respiratory viral pathogens. Seasonal, as well as age‐wise prevalence of respiratory viruses was analysed. Of these 332 cases, 32.53% (108/332) were positive for at least one pathogen. Human rhinovirus (HRV) was the most frequently detected pathogen (24.7%, 82/332) followed by respiratory syncytial virus (RSV) (4.22%, 14/332), PIV (2.11%, 7/332), and hMPV (2.11%, 7/332). Single infection was detected in 92.6% (100/108) of positive cases. Respiratory virus infections showed seasonal variation, with peaks during the rainy season followed by winter season, and were most common in patients under 1 year of age. Phylogenetic analysis of HMPV positive samples confirmed the circulation of A2 subgroup in the study area. The present study is first of its kind and adds to our knowledge of the epidemiological characteristics of these common respiratory viruses among patients with ARTIs in the study area. J. Med. Virol. 89:553–558, 2017.

Co-circulation of all four dengue virus serotypes: First report from Odisha

The present report describes the detection of co-circulation of all the four dengue serotypes along with rarely detected dengue viruses (DENVs)-4 for the first time in Odisha. One hundred and forty-eight blood samples were tested for dengue NS1 antigen ELISA and IgM antibody (Ab), and twenty early samples were subjected for type-specific multiplex reverse transcription-polymerase chain reaction (RT-PCR). Twenty-three samples found positive for dengue NS1 and/or IgM Ab; five were positive by RT-PCR. DENV-4 was detected in one sample, DENV-2 in two and 2 were co-infected with DENV-1 and 3. Co-circulation of all four dengue serotypes in Eastern India emphasises the need of molecular monitoring of circulating DENV serotypes.

Comparison of bluetongue virus detection and quantitation methods in south India

INTRODUCTION Bluetongue (BT), a vector-borne viral disease, primarily affects sheep. Of the 26 serotypes of BTV identified so far, 22 are reported to be circulating in India. Due to an increase in vector population and delays in disease diagnosis, the BT control program heavily relies on rapid and confirmatory diagnosis. Polymerase chain reaction (PCR)-based real-time detection assays may be an ideal method to detect the BTV genome in animal blood at an early stage of infection. METHODOLOGY In this study, a SYBR green-based real-time RT-PCR assay was evaluated, validated, and compared with conventional RT-PCR. The specificity and sensitivity of an assay using BTV-2 RNA extracted from tenfold serially diluted (starting from 1.0 TCID50/mL) cell culture virus was also evaluated. RESULTS While conventional RT-PCR could detect 3.16 × 10(2) TCID50 of virus/mL, the real-time PCR test had a detection limit of 3.16 × 10(-4) TCID50/mL. Melting curve analysis indicated the absence of non-specific amplification (R(2) = 0.987). Out of the 32 infected blood samples examined, 24 tested positive for BTV RNA. Seven that were found negative through conventional PCR tested positive through real-time PCR. CONCLUSIONS These results showed that the SYBR green-based real-time PCR assay is rapid, sensitive, and equally specific in the diagnosis of BT in BTV-affected animals.