2.1 Study site
The Indian Council of Medical Research (ICMR)-National Institute of
Virology (ICMR-NIV) in Pune, Maharashtra state is a part of the Indian
Rotavirus Surveillance Network supported by the Indian Council of
Medical Research (ICMR), New Delhi since 2005. The National Rotavirus
Surveillance Network (NRSN) is a multi-centric project conducted at four
referral and seven regional centers across India. Each center has
peripheral in-patient facilities that collect the clinical data and
specimens and send them to the corresponding referral and regional
laboratories for testing and characterization. The criteria for
recruitment, stool sample collection, laboratory detection, and genotype
characterization protocols used were common at all sites. ICMR-NIV, Pune
is one of the referral centers that represents the West Zone of India.
The stool specimens collected from the West Zone consisting of four
cities and seven hospitals, namely Pune (KEM Hospital, Bharati Hospital
and Shaishav Clinic), Mumbai (Lokmanya Tilak Municipal GH & Medical
College), Ahmadabad (BJ Medical College & Civil Hospital), and Surat
(Surat Municipal Institution of Medical Education & Research) during
2013–2016 were included in the present study. These hospitals are
tertiary-level health care centers, providing both general and
specialized medical care.
2.2 Enrolment criteria and clinical assessment
A case of acute gastroenteritis was defined as the passage of ≥3 watery
stools in a day with or without associated symptoms such as vomiting,
fever, and abdominal pain. All patients were examined for fever, number
of episodes and duration of vomiting and diarrhea, extent of dehydration
and treatment for the assessment of disease severity score (Ruuska and
Vesikari, 1990). According to the scores obtained, the disease condition
of each patient was categorized as mild (scores 0–5), moderate
(scores 6–10), severe (scores 11–15) and very severe (scores 16–20).