Q. What is prevalence of diarrheal disease?
A. Diarrhea is second leading cause of death only surpass by respiratory tract infections (RTI) and pneumonia, constituting 17% of all under five mortality world wide.(1,2) It is estimated that incidence of diarrhea in India is 1.71 episodes/ person /year in rural India and 1.09 episodes/person /year in urban India.(3)

Q. What is rotavirus?
A. Rotavirus is a wheel like icosahedral reoviridae double stranded RNA virus. It is subdivided into serogroup A-G and sub group 1 or 2. Group A rotavirus causes most of the human diseases .The outer viral caspid is made of protein VP7 (which determine G serotype) and VP4 (which determine P serotype) .Each rotavirus is designated by G serotype and P serotype followed by P genotype in bracket e.g. G1P1A[8]. G1-4 and G9 are predominant 5 strains in USA and responsible for 90% of rotavirus gastroenteritis (RVGE) .Out of these infecting strains, G1 causes 75% of disease. It is very stable and may remain viable if not disinfected. Rotavirus causes diarrhea in maximum among children in age 6-32 month and 13.3% of rotavirus infection involve children < 6 months. Rotavirus diarrhea is markedly seasonal in temperate climate with peak incidence occurring in the spring and winter season. (4)

Q. What is disease burden of rotavirus globally?
A. It is estimated that rotavirus causes 160 million episodes of diarrhea world over in children < 5 years, out of which 25 million need outdoor visit, 2.5 million require hospitalization and 0.6 million succumb to it. That means a death due to rotavirus every minute. (4, 5) Thirty one -87% of health care associated diarrhea are rotavirus out of which one third are severe. The incidence is 0.3 to4.8 /1000 hospital day. (4)

Q. What is disease burden of rotavirus in India and other developing world?
A. In the Indian Rotavirus Strain Surveillance Network from 2005 to 2007, rotavirus was found in approximately 39% of 4243 enrolled patients. (4) In other study from Chandigarh, rotavirus constituted 11.5% (25/218) of total diarrheal episodes and 22 % (25/115) among the children affected with acute diarrhea. (6) In India rotavirus causes more than 1.2 lakhs deaths annually, 4.5 lakh hospitalization, 5 million clinic visits and 25 million diarrheal episodes in under 5 children.(4,5) Study has also documented earlier onset of rotavirus disease in India. Rotavirus shows marked seasonality in northern temperate climate but less seasonality in southern location with tropical climate. This is due to high circulation of virus in environment with children getting exposed at early age and contracting severe disease. The most frequent strain in India were mainly G2P[4] (25.7% of strain) , G1P[8] ( 8.5% ), G9P[8] ( 8.5%) in combination with other types.(4)

Q. What is the mode of transmission of rotavirus?
A. Rotavirus spreads through feco-oral spread, close person to person contact and by fomites.

Q. Is there any difference in epidemiology of rotavirus infection in developing and developed nation?
A. There is no difference in epidemiology of diarrhea, incidence is same in developed and developing nations. It spreads from person to person hence it is difficult to control through improvement of hygiene and sanitation alone. Difference lies in the outcome of severe diarrhea by rotavirus, chances of death by rotavirus diarrhea is only 1:50000 in USA as compare to 1:210 in developing countries due to lack of proper medical care.(5)

Q. What types of vaccines are available for control of rotavirus infection?
A. Two live oral vaccines are licensed in India and internationally.

• Human monovalent live attenuated vaccine derived from human rotavirus strain 89-12 grown in vero cell culture and contain G1P1[8] strain. (Rotarix by GSK)
  
  
• Human bovine pentavalent live vaccine which is five reassortants between the bovine WC3 strain and human G1, G2, G3, G4, and P1A rotavirus strain grown in vero cells. (Rotateq by MSD)