Indian Pediatrics 2003; 40:328-331 

Prevalence of Antibodies to Hepatitis A and Hepatitis E Virus in Urban School children in Chennai

B. Mohanavalli, E. Dhevahi, Thangam Menon, S. Malathi*, S.P. Thyagarajan

From the Department of Microbiology, Dr. A.L. Mudaliar, Post Graduate Institute of Basic Medical Sciences, Taramani, Chennai 600 113, and Department of Pediatric Gastroenterology*, Institute of Child Health and Hospital for Children Egmore, Chennai 600 008, India.

Correspondence to: Dr. S.P. Thyagarajan, Professor & Head, Department of Microbiology, Post Graduate Institute of Basic Medical Sciences, Taramani, Chennai 600 113, India. E-mail: [email protected]

Manuscript received: January 10, 2002; Initial review completed: March 13, 2002;

Revision accepted: November 22, 2002.

With similar feco-oral mode of transmission of Hepatitis A and E viruses, and improving levels of personal hygiene among higher socioeconomic population, periodic surveillance on HAV/HEV exposure pattern may be of immense public health value. One such attempt was made in Tamilnadu, India by analysing the presence of antibodies to HAV and HEV in 185 healthy children of 6 months to 12 years of age. While anti HAV positivity was 96.9% by 12 years of age, anti HEV positivity fluctuated between 5.3-16.7%. The study suggests the necessity for developing a vaccine for HEV to prevent the frequent occurrence of HEV outbreaks in India, since natural HEV exposure does not bestow significant protection as observed in HAV.

Key words: Hepatitis A, Hepatitis E, Prevalence.

Hepatitis A and Hepatitis E are both enterically transmitted virus infections resulting in sporadic and epidemic forms of acute hepatitis in developing countries(1). Both these viruses do not cause chronic hepatitis. In India HAV is still the major cause of sporadic acute hepatitis(2,3) whereas HEV is the major agent for epidemics in adults(4). The illness due to HAV is age related, whereas HEV occurring during pregnancy results in high mortality. Fulminant hepatic failure is higher in coinfections of A and E, than in single infection(5). Since, HAV and HEV are spread through orofecal route, the infection rate is expected to be similar. Tandon et al.(6) reported that 90% of Indian children in the age group 5 to 10 years had anti-HAV antibodies. Recent reports from our country have shown a variable prevalence in HAV exposure in middle and upper socioeconomic strata(7,8). It is therefore imperative to know the exposure pattern of these two viruses in children in this part of the Indian subcontinent, and hence the present study.

Subjects and Methods

The study group consisted of 185 healthy children of age group 6 months to 12 years from Balamandir orphanage and a govern-ment higher secondary school in Royapettah, Chennai which catered to lower and lower middle socioeconomic strata. Informed consents were obtained from the concerned authorities in the orphanage and from the parents of the school children. The serum samples were screened for anti-HAV IgG using commercial ELISA kit (Hepanostika, Organon Teknika) and anti-HEV IgG using in-house peptide ELISA (comprising amino-acids 91-123 ORF 39 synthesized using an automated peptide synthesizer. Milligen; Millipore, Bedford, MA).

Results

Of the 185 children, 83.2% were positive for anti HAV-IgG and the positivity was lowest i.e., 31.6% (6/19) among the age group of 6 months to 2 years followed by a sharp increase which reached a peak of 96.9% in the age group 10-12 years (Table 1).

Table I

Age-Stratified Anti-HAV-IgG and Anti-HEV-IgG Positivity Pattern in Children

Age group (years)	Number of subjects	n	Anti-HAV-IgG positivity (%; 95%CI)	n	Anti-HEV-IgG positivity (%; 95%CI)
0- 2	19	6	(31.6; 12.3-56.8)	1	(5.3; 0.0-26.6)
2- 4	22	18	(81.8; 59.3-95)	2	(9.0; 0.8-29.6)
4- 6	55	46	(83.6;71.0-92.3)	4	(7.3; 1.9-17.7)
6- 8	38	37	(97.4; 85.0-99.9)	3	(7.9; 1.5-21.6)
8-10	18	15	(83.3; 58.1-96.7)	3	(16.7; 3.2 - 41.8)
10-12	33	32	(96.9; 83.8-99.9)	3	(9.0; 1.7-24.6)
Total	185	154	(83.2; 77.0-88.3)	16	(8.6; 5.0 - 13.6)

 

The age wise positivity of anti-HEV-IgG showed a different pattern with 5.3% (1/19) among six months to 2 years and 9% in the group between 2-4 years of age. A plateau of 7.3 to 7.9% was maintained between 4-8 years. The positivity was highest 16.7% (3/18) in the age group of 8-10 years.

The mean prevalence of anti HAV was 83.2% and anti HEV was 8.6% in children. Comparison of the HAV and HEV exposure pattern in the 185 children studied revealed that there is a significant difference in the exposure rate of children to these two viruses. (P <0.0001) (Fig. 1).

Fig. 1. Analysis of age vs exposure pattern of infection with HAV and HEV in children

 

Discussion

This study shows that exposure to HAV among the children reached 96.9% by the age of 12 years. This prevalence is similar to the results reported by Aggarwal et al.(8) and Arankalle et al.(10) where they reported >95% HAV exposure by late childhood. Dhawan, et al.(7) have shown a higher prevalence in lower socioeconomic group compared to the higher socioeconomic groups. The children in the present study also belonged to a lower socio-economic group but were residing in a cosmopolitan city, Chennai. The exposure to HEV was however low compared to HAV in the present study. This low positivity of 8.6% for HEV is signifi-cantly lower than the HEV exposure rates of 64% of children below 5 years and 59% below 10 years reported by Aggarwal et al.(11), and also lower than 23.8% as reported by Mathur et al.(12). However it was similar to the results of 0-9% by Arankalle et al.(10) and studies from Somalia(13) and Hong Kong(14) where a low prevalence to HEV has been documented. In this study, 5.3% of children less than 2 years had been exposed to HEV, whereas none of the children below 18 months had these antibodies in the study by Arankalle et al.(10).

In the background of 91.3% sensitivity and 66.6% specificity of this in-house anti-HEV Elisa kit shown by Mathur et al.(12) in comparison with Genelabs anti HEV Elisa kit, the limitation of the present peptide based assay has to be borne in mind while interpreting the low HEV exposure rate observed in the present study. In addition the smaller sample size of study subjects has also to be viewed as a limitation in this study.

The seroprevalence of HAV throughout India seems to be similar but exposure pattern to HEV seems to be comparatively low. Since, these two viruses are spread by orofecal route, it would be of utmost importance to provide safe drinking water and proper sanitary conditions.

Acknowledgement

The financial assistance of Indian Council of Medical Research by project no: F.No. 5/4/8/4/93-ECD-I a part of which is being presented in this publication is gratefully acknowledged.

Contributors: All the authors were involved in conceptualization, design, data collection, analysis and writing the paper. BM had an untimely demise and posthumously included as first author.

Funding: Indian Council of Medical Research, Ansari Nagar, New Delhi 110 029.

Competing interests: None declared.

 References