Hepatitis B is a life-threatening infectious disease throughout the world. Data from WHO shows that more than 257 million of the world population are affected by hepatitis B and 887,000 die each year due to complications of hepatitis B. Indonesia is a moderate to high endemic hepatitis B country, with a hepatitis B carrier reaches 5-20 percent of the population.
To date, there have been ten types of HBV genotypes identified (from A to J) based on differences> 8% in genetic viruses, especially in HBV surface genes area. The HBV genotype can further be classified into several subgenotypes based on a 4-8% nucleotide difference.
So far, genotype B is the dominant genotype found in Indonesia. Followed by genotypes C, D, and A. Urbanization and migration of residents can change the dominance of this genotype, especially in areas with high mobilization such as Surabaya.
There is still the possibility of finding new subgenotypes due to crossing (B7, B8, and B9), as in several other regions in Indonesia. HBV genotypes play a role in disease progression, clinical manifestations, and response to therapy. HBV genotype is also related to the response to interferon and is important for the development of hepatitis B vaccine.
This study aimed to determine the incidence of hepatitis B and identify genotypes and subgenotypes of HBV in SMF Internal Medicine Dr. Soetomo, Surabaya. HBsAg patients were examined to determine whether hepatitis B was positive. In positive patients, genotypes and subgenotypes were further examined using a nested PCR- direct sequencing technique followed by phylogenetic tree analysis using Genetyx for Windows software by comparing genetic sequences of samples held with genetic sequences reference from GeneBank.
In this study, 36 patients with symptoms of liver disease were found in Endoscopic Clinic, SMF Internal Medicine, Dr. Soetomo, Surabaya. They were dominated by men and middle-aged (41-60 years). Twenty patients (55.55 percent) were found to be HBsAg positive. Out of these patients, 75 percent (15 out of 20) showed positive HBV DNA on PCR examination. Samples with negative HBV DNA can be caused by variations in the attachment site of the primary PCR or patients who have previously taken anti-viral drugs.
From the phylogenetic tree analysis, 15 samples had the same kinship in 1 tree, the genotype B branch of Indonesia (B_D23678_204), but far from the genotype B branch of other countries such as Japan.
It shows that hepatitis B sufferers in Surabaya are dominated by Indonesian strain B genotype. In general, Indonesia is one of the countries with a variety of HBV genotypes, due to the many ethnicities, geographical locations, and populations. Various ethnic groups in Indonesia allow migration and urbanization to cause the spread of HBV genotypes.
Surabaya is the second-largest city in Indonesia where traders, migrants, and visitors from various cities and countries gather. However, our study showed that there was no shift in the HBV genotype pattern in the Surabaya population.
In further subgenotype analysis, it was found that 7 out of 15 of our study samples (46.67 percent) had B3 subgenotypes, six other samples were present in different phylogenetic tree branches but were still related to B3 subgenotypes, while the remaining two samples could not be identified. This can be due to the nature of the B3 subgenotype which is spreading, not monophilic (1 tree branch), thus allowing the quasi-subgenotypes of B3 in the hepatitis B population in Surabaya that need further studies. (*)
Author: Citrawati Dyah Kencono Wungu, dr., M.Si
Details of this research available at:
https://ejournal.warmadewa.ac.id/index.php/warmadewa_medical_journal/article/view/1032
http://dx.doi.org/10.22225/wmj.4.1.1032.6-13
Citrawati Dyah Kencono Wungu, Mochamad Amin, Ulfa Kholili, Gwenny Ichsan Prabowo, Poernomo Boedi Setiawan, Soetjipto, Retno Handajani (2019). Distribution of Hepatitis B Virus Genotypes Among Patients at Internal Medicine Unit, Dr. Soetomo General Hospital,
Surabaya. Warmadewa Medical Journal, 4(1): 6-13
