The demographic and clinical characteristics of the infants age 2-12 months who were hospitalized for acute gastroenteritis according to their rotavirus status is displayed in Table 1 above. Out of 424 stool samples that were tested, 245 (57.8%) were male and 179 (42.2%) were female infants. Out of the 245 males tested for rotavirus diarrhoea, 96 (39.2%) had acute rotavirus diarrhoea, and out of 179 female infants tested, 57 (31.8%) were infected with rotavirus. Both male and female infants had the same chance of having acute rotavirus diarrhoea (p =0.126).
Overall, there was a significant age-specific association between infants who had rotavirus diarrhoea and those that were negative for rotavirus (p =0.041). The age specific rotavirus infections increased from 2-4 months, 49/118 (41.5%), peaked in the 5-8 months category 70/181 (38.8%) and subsequently dropped in the infants aged 9-12 months 34/125 (27.2%). Infants who had acute rotavirus diarrhoea did not differ significantly from those who did not have rotavirus diarrhoea in the type of treatment that they received ( p = 0.123), even though the majority of infants who presented to the hospital with acute diarrhoea received intravenous fluid 238/424 (56.1%).
Infants who had rotavirus acute diarrhoea were not significantly different from those that did not have rotavirus diarrhoea in the number of episodes of diarrhoea (p = 0.969), episodes of vomiting (P =0.219), duration of diarrhoea and vomiting, (P = 0.402. and 0.188 respectively). Infants who received 1 dose or 2 doses and those not vaccinated at all had the same chance of having acute diarrhoea due to rotavirus (p = 0.351). Infants who had acute rotavirus gastroenteritis differed significantly from those who were negative for rotavirus by fever, (P = 0.010). The median duration of acute diarrhoea in days was 3 days (IQR, 2-3), and the median episodes of diarrhoea in 24 hours were 5 episodes (IQR, 4-6). The median duration of vomiting was 2 days (IQR, 1-3) while the median episodes of vomiting in 24 hours were 3 episodes (IQR, 2-4).
Figure 1 below shows the age distribution of rotavirus genotypes which were responsible for the acute diarrhoea that was seen in infants who presented with acute diarrhoea at UTHs Children’s Hospital. Overall, there was no significant difference in the genotypes that infected infants aged 2-12 months who presented with acute diarrhoea in 2016. Most infants aged 2-4 months had acute diarrhoea due to G2P 15/42 (35.7%) followed by G1P 11/37 (29.7%). 4/22 (18.2%) of rotavirus infections that occurred in this age group were due to mixed genotype infections. A few infections were caused by G2P 4/7 and G9P 3/4. There was no G1P infections in this age group. Infants age 5-8 months were infected with all rotavirus genotypes which were detected in this study with most infections being caused by G2P 20/42 (47.6%), followed by G1P 19/37 (51.4%) and mixed infections 13/22 (59.1%). The older age group, 9-12 months were infected with G1P 7/37 (18.9%), G2P 7/42 (16.7%), and mixed infections 5/22 (22.7%).
Out of 424 samples which were eventually tested for human group A rotavirus VP6 antigen, 153 stool samples, representing 36.1 %, (95% CI 31.5% to 40.9%) were positive for rotavirus VP6 antigen and 271 (64%) were negative. Rotavirus acute diarrhoea occurred throughout the year with highest pick occurring in the cool dry months through to the dry hot months of the year, as shown in the graph below.
Most rotavirus infections which occurred in infants in this study were because of G2P 42/116 (36 %), followed by G1P 37/116 (32%), mixed infections 22/116 (19%). Rotavirus genotypes that were responsible for the dual infections that occurred in the infants who were studied included, G9P/P, G2P/P, G1P/P/P, G1/G2P, G1P/P, G-P/P, G8/G3P, G3/G9P, G1P/P, G1/G2P, G2/G9 P/PG2 P/P G2/G9 P, G9P/P, G1/G9P,G1/G12P. G2P was only responsible for 7/116 (6%), G1P 4/116 (4%.), and a few G9P 4/116 (3%) as indicated in Figure 3 below. Figure 4 below shows that monthly variation of acute diarrhoea infections which occurred in infants aged 2-12 months at UTHs Children’s Hospital in 2016. Many infections which occurred in January 2016 where as a results of G2P  8/22 (36.4%); followed by G1P 6/22 (27.3%); followed by G2P 4/22 (18.2%) and a few mixed infections 3/22 (18.2%). There was a reduction in acute diarrhoea cases due to rotavirus in February through to May 2016, with a few infections that occurred in these months being caused by G1P, mixed infections and G2P. The majority of acute diarrhoea infections which occurred in June (coolest month in Zambia) where as a results of G1P 16/23 ( 69.6%), followed by G2P 3/23(13.0%), mixed infections 3/23 (13.0%) and one infection was due G2P 1/23 (4.4%).
The greater part of infections that occurred in July were due to G1P 4/8 (50.0 %), followed by G2P 2/8 (25.0%), and mixed infections 2/8 (25.0%). In August, eleven acute diarrhoea infections which occurred in this month were as a result of G2P 4/11 (36.4%), followed by G1P 3/11 (27.3%), mixed infections 3/11 (27.3%), and one infection which was caused by G1P strain. September is the beginning of the hot dry season in Zambia and that is where most rotavirus infections 33/116 took place. The common genotype which caused acute diarrhoea in infants who presented to the hospital in this month was G2P 23/33( 69.7%). The rest of the acute rotavirus diarrhoeas which occurred in September were due to mixed infections 7/33 (21.2%), G2P[4 2/33 (6.1%) and G1P 1/33 (3.0%). There was a reduction of acute diarrhoea due to rotavirus in the months of October through to December in 2016, with the a few rotavirus acute diarrhoea infections being caused by G1P, G1P, G9P, G2P and mixed infections.
As shown in figure 5 below, most rotavirus acute diarrhoea infections which occurred in 2016 were mild to moderate. The median Vesikari score for acute diarrhoeal infections the occurred due to G1P and G2P was 6, indicating moderate infections with Vesikari score between 6-10. The median Vesikari score for infections which were due G1P and mixed infections was 7, causing moderate acute diarrhoea with Vesikari scores ranging between 6-10, while 4 and 8 were the median Vesikari scores for infections caused by G2P and G9P respectively. This data shows that most of the acute diarrhoea infections which occurred in 2016 were mild to moderate infections; we did not record any severe diarrhoea except for 3 cases which were because of G2P and had a Vesikari score of 11.