Asian Scientist (March 30, 2023) — An adenovirus outbreak in the eastern Indian state of West Bengal infected more than 12,000 children between January and March this year. This outbreak was unprecedented in scale and severity.
Cases of adenovirus infection were also reported in other cities like Mumbai, Pune, Bangalore and Jaipur, but the situation in West Bengal was serious. According to government statistics, the the death toll is 19. However, pediatricians say that more than 150 children have died from adenovirus infections and related complications.
The National Institute of Cholera and Enteric Diseases (NICED) in Kolkata analyzed the genetic makeup of adenovirus samples collected from affected children to determine the virus serotype. The serotype tells us how viruses are grouped based on the type of surface antigen present. Surface antigens allow bacterial attachment to and invasion of host cells and evasion of the host’s immune defense mechanisms. Serotype analysis showed that serotypes 3 and 7 and recombinant strain 7/3 (the strain obtained by combining type 3 and type 7 genetic material) were found in most cases in West Bengal.
Pediatrician Apurba Ghosh said Asian scientific journal that the adenovirus epidemic has occurred before in West Bengal, but “the magnitude and severity of this year’s epidemic are unprecedented.” He added that children as young as two years of age are particularly vulnerable as their lungs are not fully developed.
This infection is limited to the upper respiratory tract in older children and young adults. But it can spread further into the lower respiratory tract in children between three months and two years of age, causing adenoviral pneumonia.
Prabhas Prasun Giri, Associate Professor of Pediatrics and PICU Manager, Institute of Child Health, KolkataHe said that adenoviral pneumonia severely affects the lungs and compromises immunity, increasing the chances of secondary bacterial infections and bacterial sepsis.
Doctors interviewed for this story said that babies born during the pandemic are used to living in a disinfected environment and have not acquired immunity to common infections. This “immunity gap” has also contributed to the severity of infections.
Although the virus had mainly affected children under the age of two, a teenager lost his life to an Adenovirus infection. Subhrojyoti Bhowmick, clinical director of the Peerless Hospital & BK Roy Research Center, where the girl was admitted, explained that the teenager had spinal muscular atrophy, a medical condition that weakens the respiratory muscles. Then the “adenovirus infection further weakened her respiratory muscles, preventing them from performing routine functions,” she said.
limited surveillance
In Asia, large-scale adenovirus outbreaks have also occurred in China, Taiwan, Singapore, and Malaysia. Furthermore, adenovirus is believed to be the reason behind the global outbreak of viral hepatitis last year because adenovirus remains the most frequently detected pathogen in hepatitis cases tested, according to the World Health Organization (WHO).
The WHO added that assessing whether the rate of hepatitis cases with adenovirus infections is higher than expected in the population is challenging due to limited adenovirus surveillance in most countries.
Between November 2012 and July 2013, Singapore witnessed a marked increase in adenovirus type 7 (Ad7) infections among children. In November 2012, Singapore’s KK Hospital for Women and Children reported the first confirmed case of adenovirus type 7. The number of pediatric patients hospitalized increased from 32 between January and July 2012 to 200 between January and July 2013.
Many studies, mainly in Singapore, have been conducted to understand this sudden and serious outbreak. In the first large-scale study of adenovirus strains, researchers led by Duke-NUS Medical School studied more than 500 clinical samples, mostly from pediatric patients. They found an increase in types 4 and 7 compared to other strains in the pediatric population.
Based on the study results, the authors suggested that public health officials and doctors in Singapore consider antiviral therapies and adenovirus vaccines. They also recommended systematic studies of clinical HAdV genotypes to identify patients at risk of severe disease.
Giri said that adenovirus vaccine development should be seriously considered. He noted that many repeat hospitalizations of Ad7-infected children occur due to recurrent infections and postinfectious bronchiolitis obliterans (PIBO), a serious long-term respiratory condition, which has a poor prognosis and negatively affects children’s quality of life. However, studies on BOPI risk factors are limited.
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Image: Shelly Liew/Asian Science Magazine
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