Prevalence and Clinical Manifestations of Rotavirus and Adenovirus Infections in Children Under Five Years Old in Katsina State, Northwestern Nigeria. *Mukhtar .G.L

Mukhtar .G.L. Gastroenteritis is a leading cause of childhood morbidity and mortality in developing countries. Our aim was to determine the prevalence of rotavirus and adenovirus infection and their co-infection in children aged < 5 years in Katsina State, Northwestern Nigeria. A total of 400 (322 diarrhoiec and 78 non-diarrhoiec) stool specimens were collected from children attending six hospitals located across the three senatorial zones of the state from June 2013 to April 2014. Their socio-demographic information and clinical presentations were noted with the aid of questionnaire. Viral antigens were detected by enzyme linked immunosorbent assay (ELISA). Rotavirus was detected in 5.3% of the diarrhoiec and none in the non-diarrhoiec specimens while adenovirus was detected in 12.4% of the diarrhoiec and 5.1% of the non-diarrhoiec specimens. Co-infection of rotavirus and adenovirus was observed in 0.6% of the diarrhoiec children. Generally, children < 2 years old were more vulnerable to rotavirus and adenovirus infection. There was a significant association between dehydration and rotavirus and adenovirus infections (p<0.05).


Inclusion criteria and Exclusion criteria
The inclusion criterion was any child between the ages of 0-5 years of both sexes who were presented or admitted for diarrhoea illness in the selected hospitals. The exclusion criterion was children above 5 years of both sexes. A diarrhoea case in the study was defined as a child passing loose, watery or a bloody loose stool three or more times in a 24-hour period as reported by the parents. The control was considered as any child that was presented for an illness other than diarrhoea and with no history of it on the day of, or in three weeks preceding sampling.

Approval
Ethical approval was obtained from the ethical committee of Katsina State Ministry of Health.
Sample collection 320 faecal specimens were collected from children between the ages of 0-5 years that were presented or admitted at clinics or hospitals for acute diarrhoeal illness, and 80 from non diarrhoeic patients as controls. The specimens were collected in a clean, labeled screw capped tubes and transported immediately in ice-cooler boxes to Postgraduate Microbiology Laboratory Ahmadu Bello University, Zaria and stored at 4ᵒC.

Sample processing and laboratory analysis
A 10% faecal suspension was prepared by adding 0.1g of solid stool or 100µl of liquid stool to 900µl distilled water in a screw cap test tube, vortex 30-60 seconds to mix thoroughly.

Viral Antigen Detection using ELISA
Each of the 10% faecal suspension was screened for the presence of rotavirus and adenovirus antigens using commercially available enzyme immunoassay (Diagnostic Automation, Inc, US) kit. The assay was done strictly according to the manufacturer`s instruction in order to determine enteric virus positive specimens.

Data analysis and presentation
Analysis of rotavirus and adenovirus infection in children according to age, sex and dehydration was done using SPSS version 20.0. P values < 0.05 were considered statistically significant.

Result:-
A total of 400 stool samples were screened for rotavirus and adenovirus antigen. Of these, 322 and 78 were diarrhoeic and non-diarrhoiec samples respectively. Among the 322 children that were presented with diarrhoea, 5.3% (17/322) were positive for rotavirus and no viral antigen was detected in the non-diarrhoeic samples. Rotavirus was significantly associated with diarrhoea in this study (χ 2 = 4.3008, df= 1, p= 0.038095). Adenovirus was detected in 12.4% (40/322) of the children with diarrhoea and in 5.1% (4/78) of the non-diarrhoeic children. Even though, there was no statistically significance difference of adenovirus infection between the diarrhoeic and non-diarrhoeic children (χ 2 = 3.4124, df= 1, p= 0.064707), those with diarrhoea were about three times more likely to be infected with adenovirus than those without diarrhoea (OR = 2.6241, 95% CI= 0.9098-7.5685) ( Table 1).
Co-infection of rotavirus with adenovirus was observed in 0.6% (2/322) of the diarrhoiec children ( Figure 1). Analysis by sex and age showed that co-infection was found in one male and one female with 24 and 36 months old respectively. All the co-infected children were found in the diarrhoeic population. Examination of their stool samples showed that they both had watery stool and which was passed atleast1-3 times in 24 hour period.
82.4% of positive cases of rotavirus gastroenteritis were under 2 years of age with highest prevalence in children 7-12 months of age, while adenovirus was most prevalent among children aged 0-6 months ( Table 2).
In this study, rotavirus and adenovirus infections were significantly associated with dehydration (P<0.05). Among the diarrhoeic children positive for rotavirus, the degree of dehydration among the children was found to be mild, moderate, severe and absent in 13.5%

Rotavirus Adenovirus
The prevalence of rotavirus infection in this study is comparable to the report of Kuta   The lower prevalence of rotavirus observed in this study might also be due to seasonal factor or long period of specimen storage, which might have led to disintegration of the viral particles, hence insufficient antigen in the specimen. In addition, the patients might be shedding rotavirus antigen lower than the detection limits of the test assay.
Co-infection of rotavirus with adenovirus in this study was observed in 0.6% of the diarrhoeic children. This result is comparable with the results of Nimzing et al, (2000) where a prevalence of 1.1% was reported. However, our prevalence is lower than that previously reported by Aminu et al, (2008) and Tran et al, (2010) where a prevalence of 3.2% was obtained. The dual infection observed in this study may be attributable to either a single virus is responsible for the diarrhoea or the two viruses act in synergy. More so, the multiple infections observed may be attributable to poor hygienic conditions and overcrowding peculiar to the study area. Poor hygienic condition has been suggested to contribute to multiple infections in developing countries (Guix et al., 2002).
Rotavirus infection was observed to be slightly higher in male (5.5%) than in female (5.0%) children, hence there was no statistically significance difference in rotavirus infection between male and female children with diarrhoea in this study (P>0.05). This is similar to other studies in Nigeria where rotavirus was detected in slightly higher rates in male than in females ( where they found no any significant difference in infection between both sexes. The reason for the lack of statistically significance difference in detection rate between male and female children may be explained by the fact that at younger age, both sexes have little or no major differences in their life style. Alternatively, the slight differences observed might be due to sex susceptibility or by chance, whether this difference is due to sex susceptibility or by chance is however questionable and needs further investigation. The highest prevalence of rotavirus infection occurred in the age-group 7-12 months (7.7%). This age-group distribution is comparable to previous reports by Junaid et al, (2011) and Kajbaf et al, (2013) where they reported higher prevalence in children 7-12 months old. The least prevalence of rotavirus infection was observed in the agegroup 0-6 months. The low rate of infection in infants may be attributed to a higher rate of breast feeding thereby providing partial protection due to present of maternal antibodies in breast milk.
The detection of rotavirus mostly in children under 2 years in this study is in accordance with the assumption that in under-developed areas the early peak of rotavirus diarrhoea may result from early exposure to contaminated sources as well as over-crowded homes, more so, since almost all humans experience at least one rotavirus infection by 3 years of age and circulating rotavirus antibodies remain detectable indefinitely (Bernstein and Ward 2004). This may lead to protection against rotavirus infection and disease or at least milder forms of disease, which result in lower rate of rotavirus gastroenteritis in older children. Rotavirus and adenovirus shedding was highest when a combination of all the three symptoms (diarrhoea, fever and vomiting) occurred together and lower when two occurred together and lowest when diarrhoea occurred alone. These clinical features observed are the major symptoms that accompanied rotavirus diarrhoea. This is similar to the observations made by Aminu (2008)

Conclusion:-
In this study, rotaviruses and adenoviruses were found to be an important cause of diarrhoea in children 0-5 years old in Katsina State, Nigeria. However, the prevalence of rotavirus infection among the children appears to be relatively low while adenoviruses were shown to circulate at a higher frequency in association with gastroenteritis in children less than five years old. Our study provides evidence that adenoviruses can be a leading cause of viral gastroenteritis infection in children less than five years of age.
Rotavirus infection was more prevalent children 7-12 months old while adenovirus virus was more prevalent in children 0-6 months old. Rotavirus and adenovirus detection was greatest when diarrhoea, vomiting and fever occurred together and lowest when diarrhoea occurred alone.

Recommendations:-
Extensive research on adenoviruses should be carried out because their role and position in viral gastroenteritis as shown by this study and many others, is becoming increasingly higher as compared to other viral agents of gastroenteritis.
Since the detection of rotavirus in this study was mostly in children 2 years and below, rotavirus vaccine should be included into the Expanded Program on Immunization (EPI) as this will greatly reduce rotavirus associated morbidity and mortality within this group.