Adenovirus outbreak in India: seeking solutions for child mortality

Adenoviruses (AdVs) are nonenveloped, nonsegmented, linear, 26–48 Kbp long double-stranded viruses that cause moderate cold or flu-like symptoms1. Human AdV (HAdV) belongs to the “Mastadenovirus” (mammalian AdVs) and “Adenoviridae” family. In older children and young adults, it causes severe upper respiratory illnesses. In babies under 5, it causes upper and lower respiratory diseases that ultimately progress to adenoviral pneumonia. This virus also affects older people, immunocompromised, and individuals with comorbidities. It also most often infects the conjunctiva and gastrointestinal tract. Complete genomic sequence analysis by bioinformatics of this virus showed a total of 51 serotypes, including more than 70 genotypes, where they were sorted into 7 species (HAdV-A through HAdV-G)2. AdV epidemiology, clinical symptoms, diagnosis, pathophysiology, prevention, and treatment are all briefly covered in this short communication-based article. More than 12,000 confirmed cases of the AdVs were recorded between January and March, this year in the eastern state of West Bengal and India, and 150 children died as a result of acute respiratory infections and related complications due to failing to develop immunity to common illnesses. Cases of AdV infection were also reported in other cities, such as Mumbai, Pune, Bangalore, and Jaipur. AdV outbreaks of similar magnitude have also occurred in China, Taiwan, Singapore, and Malaysia, among other Asian nations. AdV type 7 infections among children in Singapore increased significantly between November 2012 and July 2013, with the first cases being identified in a hospital. According to the World Health Organization, AdVs caused the hepatitis outbreak and served as the “detective pathogen” in cases of hepatitis that were tested. The virus enters the cell through receptor-mediated endocytosis3. AdVs use the coxsackie-AdV receptor to enter cells, and a secondary connection between the pentose base and particular integrin on the target cell is also necessary. After processing, the viral genome encodes for early, intermediate, and late proteins. AdVs also contain immune evasion genes that support viral persistence by sabotaging the immune system’s antiviral response. The encoded gene’s product inhibits interferon’s cellular response and shields infected cells from cytotoxic T cells (cytotoxic T-cell/cytotoxic T-lymphocyte/CD8+ T-cell) and tumor necrosis factor4. The National Institute of Cholera and Enteric Diseases in Kolkata analyzed the genetic composition of the AdV samples obtained from the affected children. It determined that serotypes 3 and 7 and the recombinant strain 7/3 were responsible for the majority of cases. Approximately 20% of newborns in Asia are infected by pneumonia. The typical symptoms of adenoviral infection in the respiratory system include fever, pharyngitis, coughing, sore throat, and tonsillitis, affecting at least 5%–10% of children and 1%–7% of adults. Bronchiectasis, bronchiolitis obliterans, and hyperlucent lungs in children are long-term respiratory consequences1. According to the Centre for Disease Control, adenoviral illness can also lead to acute gastroenteritis, frequent peeing, and a burning sensation during peeing. These symptoms can last 2 days to weeks after contact with the virus. Gastrointestinal symptoms can also manifest, leading to nausea, diarrhea, and abdominal pain (Fig. 1).Figure 1: Comprehensive figure of adenovirus (AdV). Genomic structure, transmission, pathogenesis, signs and symptoms, and prevention (biorender.com.). The viral structure consists of dsDNA, penton base, hexon, fiber shaft, and knob. Transmission can occur either through direct contact or through droplets. Sore throat, headache, cough, fever, nausea, and critical condition are a few signs and symptoms. AdV infects the eyes, upper respiratory, or kidney and spreads in the gastrointestinal tract, lower respiratory, lymph nodes, and other body parts. Washing hands and wearing gloves, masks, and PPE can be used to prevent this virus.AdVs are contagious and frequently spread by many routes (feces, the mouth, and the respiratory system). Aerosolized virus particles from laughing and mucus particles from coughing and sneezing are all examples of respiratory transmission. In addition, ingesting tainted food and water can transmit the disease. Furthermore, this virus can also be spread directly by touching contaminated objects and surfaces, shaking hands, embracing, and then touching your mouth or nose. The viral infection is influenced by several variables, including patient age, surroundings, temperature, and immunologically impaired individuals. AdVs were initially identified in 1953 and isolated from adenoid cell culture. AdV can be diagnosed using nasopharyngeal samples, biopsies, bronchoalveolar lavage, affected patients' excreta (urine and stool), and blood specimens following “Enzyme-linked immunosorbent assay” protocol, cell cultures method, or Polymerase Chain Reaction5. In the case of respiratory samples, nasopharyngeal discharge can be used as a fundamental approach for the direct detection of adenoviral infection. Biopsy of affected tissues and immunohistochemical stains may reveal the AdV hexon antigen in tissue5. Viral cultures can be used to identify it by conventional techniques. Serological tests have also been used widely to determine AdV infection, although their value in immunosuppression is restricted due to the shorter immune response. The complement fixation test is a reliable and sensitive approach, whereas the enzyme immunoassay immunoglobulin G antibody test is more sensitive with high efficiency6. AdV infections do not have any specific treatment. Fever reducers and pain medications can be used to treat symptoms. Antibiotics do not act against AdVs. Antiviral therapies are not beneficial for healthy people. In rare circumstances, the patients are supplied with antiviral medicine cidofovir, ganciclovir, vidarabine, and ribavirin7. Cidofovir is a cytosine nucleotide analog that blocks DNA polymerase, and the therapeutic age is delivered intravenously. 5 mg/kg every 1–2 or 1 mg/kg twice weekly is supplied as a dosage. Patients have to obtain adequate rest and consume plenty of fluids throughout the adenoviral illness8. Frequently washing hands with soap and water and maintaining adequate hygienic conditions can decrease the spread of the virus. Avoid close contact with infected person, avoid touching eyes, nose, or mouth with unwashed hands should be observed to limit the likelihood of transmission. Ethical approval The present study includes printed and published information; therefore, formal ethical clearance is not applicable to this study. Sources of funding Not applicable. Author contributions M.A.I.: original article writing. M.I.H. and P.B.: review and editing. Conflict of interest disclosures The authors declare that they have no financial conflict of interest with regard to the content of this report. Research registration unique identifying number (UIN) Not applicable. Guarantor Md. Aminul Islam.