|Year : 2020 | Volume
| Issue : 3 | Page : 144-147
Viral load and genotype of recent hepatitis E virus outbreak in Chittagong, Bangladesh
Rajat Sanker Roy Biswas1, Syduzzaman Sydu2, Shaikh Md Hasan Mamun2, Sanjoy Kanti Biswas3, Nahid Sultana3, Austin Sequeira4, Jean Bishop4
1 Department of Medicine and Microbiology, Chattogram Maa O Shishu Hospital Medical College, Agrabad, Chittagong, Bangladesh
2 Department of Medicine, Chattogram Maa O Shishu Hospital Medical College, Agrabad, Chittagong, Bangladesh
3 Department of Microbiology, Chattogram Maa O Shishu Hospital Medical College, Agrabad, Chittagong, Bangladesh
4 Department of Laboratory Medicine, SlieaGen LLC, Austin, TX, USA
|Date of Submission||16-Dec-2019|
|Date of Acceptance||12-Sep-2020|
|Date of Web Publication||21-Jan-2021|
Dr. Rajat Sanker Roy Biswas
Department of Medicine, Agrabad, Chittagong
Source of Support: None, Conflict of Interest: None
Introduction: There is an outbreak of hepatitis E virus (HEV) infection in Chittagong, Bangladesh in the year 2018. Due to unavailability of data of HEV infections in this region, objectives of the present study are to find the viral load and genotype the HEV infections. Methods: It was an observational study done in a tertiary care hospital during one year. A total of 125 Ig-M HEV positive cases were recruited tested by ELISA. After collection blood samples those were sent to Sliea Gen L.L.C, Texas, USA for detection of viral load and genotype maintaining proper procedure. Ethical clearance was taken from the hospital authority and informed written consent was taken from all patients and funding was provided by Sliea Gen L.L.C. USA. Results: Among the total 125 study patients, male was 90(72') and female was 35(29') where 7(5.6') were pregnant. Among them most 45(36.0') were at age group 30-40 years. Mean ± SD of age was 33.78 ± 14.29 years. All (100') cases were Ig-M Anti HEV positive and 9(7.2') cases were also positive for HBsAg, 1(0.8') cases were Anti HCV positive and none was Anti HAV positive. Regarding viral load Log 4-6 were found in 55(44.0') cases and >Log 6 were found in 23(18.4') cases and again 30(24.0') cases had 1000-10,000 IU/ml, 25(20.0') cases had 1,0,000-1,00,000 IU/ml and 23(18.4') cases had 1.00,000- 10,00,000 IU/ml viral load. Genotype 1F was found in 68(54.4') cases as the only genotype and no other genotype was found in the sample. Conclusion: So, in this region Chittagong, Bangladesh genotype 1F is the main genotype found and also they showed variable viral load.
Keywords: Genotype, HEV, viral load
|How to cite this article:|
Biswas RS, Sydu S, Mamun SM, Biswas SK, Sultana N, Sequeira A, Bishop J. Viral load and genotype of recent hepatitis E virus outbreak in Chittagong, Bangladesh. J Sci Soc 2020;47:144-7
|How to cite this URL:|
Biswas RS, Sydu S, Mamun SM, Biswas SK, Sultana N, Sequeira A, Bishop J. Viral load and genotype of recent hepatitis E virus outbreak in Chittagong, Bangladesh. J Sci Soc [serial online] 2020 [cited 2021 May 7];47:144-7. Available from: https://www.jscisociety.com/text.asp?2020/47/3/144/307597
| Introduction|| |
Hepatitis viruses constitute the mainstay of liver diseases in Bangladesh. Among the different viruses, hepatitis B, C, and E are contributing the most. Viral hepatitis poses a huge burden to the health-care delivery system as well as to the economy of Bangladesh. Hepatitis E virus (HEV) is the leading cause of acute hepatitis in this country, and it causes an outbreak in different regions like recently in Chittagong, Bangladesh.
Being a member of the developing world with significant poverty and poor hygienic conditions, not unexpectedly Bangladesh offers favorable conditions for nurturing HEV infection. Not only seasonal but also sporadic, nonseasonal HEV outbreaks with significant mortality have been reported from Bangladesh. Not to mention that HEV remains the leading cause of acute hepatitis and also fatal conditions such as acute hepatitis in pregnancy and acute chronic liver failure in this country.
HEV isolates have been divided into at least 4 genotypes and 24 subtypes. Genotype 1 is mostly found in isolates from Pakistan, Nepal, India, and China. Genotype 2 was detected from an epidemic outbreak in Mexico. HEV genotypes 1 and 2 are said to be the reason for the waterborne hepatitis E in developing countries like Bangladesh, and these genotypes are mainly restricted to humans. HEV genotypes 3 and 4 cause the autochthonous cases in industrialized countries and are mostly found in animals such as pigs and rats. In the United States and other countries, Genotype 3 was detected while genotype 4 was found in Taiwan, Japan, and China. However, a new strain of HEV was recently detected in chickens with hepatitis–splenomegaly syndrome. This strain was named avian HEV and was proposed to belong to either a new genotype 5 or a separate genus. Through recent researches, genotypes 6 and 7 have also been identified. Considering the heterogeneity of the HEV strains circulating in humans and other animals, development of a broadly reactive assay is needed for detection of the various HEV strains that can infect humans.
A recent outbreak of hepatitis is observed in the western part of Chittagong city of Bangladesh for the last 6–8 months in the year 2018. However, due to lack of expertise and infrastructure, detection of viral load and genotype is scarce. Hence, an observational study is designed to find the HEV genotyping with viral load in our context.
| Materials and Methods|| |
It was an observational study done in collaboration with the Department of Medicine and Department of Microbiology, Chattogram Maa O Shishu Hospital Medical College, Chittagong, Bangladesh, with a research laboratory of Texas, United States of America (USA). The period of study was 1 year, and the duration of sample collection was 5 months from August 1, 2018, to December 31, 2018, while the outbreak of hepatitis was maximum in that region. Patients with a history suggestive of hepatitis (anorexia/nausea/vomiting/yellow eye/dark urine) with a history of short duration fever or if researchers clinically suspected the patients had acute hepatitis in their background history and examination or hospital-admitted patients with clinically documented acute hepatitis biochemically or serologically were recruited in the study. Patients unwilling to provide informed consent, or unwilling to answer the questionnaire, or unwilling to donate blood for the study were excluded from the study. During that period, a total of 125 immunoglobulin M (IgM) HEV-positive cases done by enzyme-linked immunosorbent assay (Biolab Diagnostics Company Limited, Germany) were recruited as the study sample. Ten milliliters of venous blood was collected from those positive cases and mixed with ethylenediaminetetraacetic acid anticoagulant. Plasma was separated after centrifugation and preserved at -20°C. After collection of all samples, those were sent to SlieaGen LLC Research Laboratory, Austin, Texas, USA, for further analysis. During shipment, dry ice was used to maintain the temperature of the sample below -20°C. In the USA, hepatitis B surface antigen (HBsAg) (ARCHITECT i2000SR HBsAg, Abbott Diagnostics), anti-HCV (ARCHITECT i2000SR Anti-HCV, Abbott Diagnostics), IgM anti-HAV (ARCHITECT i2000SR HAVAb-IgM, Abbott Diagnostics), HEV viral load in IU/ml and HEV viral load log (RealStar HEV RT-PCR Kit 2.0), and HEV genotype were done in all the 125 samples. After doing all tests, data were sent to the primary investigation site and analyzed by SPSS-20 (IBM, Armonk, NY, USA). For the study, the Ethical Review Board (ERB) clearance was taken from hospital authority, informed written consent was taken from all the patients for data and blood collection, and FDA approval was taken to transport the sample and study in the USA. The study was funded by SlieaGen LLC research laboratory, USA.
| Results|| |
A total of 125 cases of IgM-positive HEV infection cases were recruited in the study for genotype and viral load analysis. In the study, males were 90 (72') and females were 35 (29') where 7 (5.6') were pregnant. The male-to-female ratio was found to be 2.57:1 [Table 1]. Regarding different age groups of patients, 19 (15.2') were at <20 years, 45 (36.0') were at 30–40 years, 16 (12.8') were at 40–50 years, 9 (7.2') were at 50–60 years, and 5 (4.0') were at the age group of >60 years. One patient was found at the age of 106 years. The mean ± standard deviation of age was 33.78 ± 14.29 years [Table 2]. Virus screening serology of 125 cases revealed that all (100') were IgM anti-HEV positive, 9 (7.2') were positive for HBsAg coinfection, 1 (0.8') case was positive for anti-HCV coinfection, and none was positive for anti-HAV [Table 3]. Regarding viral load, 11 (8.8') cases were found to having no viral load, 16 (12.8') had 1–100 IU/ml, 20 (16.0') had 100–1000 IU/ml, 30 (24.0') had 1000–10,000 IU/ml, 25 (20.0') had 10,000–100,000 IU/ml, and 23 (18.4') had 100,000–10,00,000 IU/ml [Table 4]a. Viral load by log revealed that < log 2 was 27 (21.6'), within log 2–4 was 20 (16'), log 4–6 was 55 (44.0'), and > log 6 was 23 (18.4') [Table 4]b. Genotype analysis of HEV revealed that genotype 1F was found in 68 (54.4') cases; 3 (2.4') cases were inhibited; in 21 (16.8') cases, required amount of viral load was not available for genotyping; and in 33 (26.4') cases, genotyping could not be done [Table 5].
| Discussion|| |
Outbreaks of acute hepatitis have been attributed to HEV since the 1950s. Acute hepatitis is seen sporadically round the year in Bangladesh. However, in 2018, there was a huge patient load of hepatitis in Chittagong, Bangladesh, and among hepatitis, HEV infection was the main causative virus. In the present study, we found that males were the main sufferers with the age group mostly in 20–40 years who are active and earning member of the family. A study done by Biswas et al. also found that the age of 20–30 years is the main age group found to be affected by the hepatotropic virus during that season and also supported by a study done by Labrique et al.
Serology of all the patients was done and found that all were IgM anti-HEV positive, 9 (7.2') were positive for HBsAg coinfection, 1 (0.8') case was positive for anti-HCV coinfection, and none was positive for anti-HAV. In the Middle East and the Indian subcontinent, HBV infection is of intermediate endemicity with a chronic HBV carriage rate of 2'–5' among the general population. In the present study, HBV coinfection with HEV was found little higher and whether HBV infection playing a role in HEV infection needs further evaluation. We found only one case of HCV coinfection among all the 125 cases. The WHO South-East Asia Region has about 30 million hepatitis C carriers, which is more than 1.6' of the total population. Our findings also share the same data. We found no anti-HAV coinfection with HEV-positive patients.
Regarding viral load in 125 samples, some had no load at all to 100,000–1,000,000 IU/ml or > log 6. As samples were collected at different days of infection, some had zero to minimum viral load and others had higher levels. Genotype analysis revealed that genotype 1F was found in 68 (54.4') cases; 3 (2.4') cases were inhibited; in 21 (16.8') cases, required amount of viral load was not available for genotyping; and in 33 (26.4') cases, genotyping could not be done. HEV is a nonenveloped, positive-sense, single-stranded RNA virus. Four HEV genotypes 1, 2, 3, and 4 have been recognized. Each HEV genotype appears to have a specific geographic distribution. Genotype 1 HEV has been isolated from human cases of epidemic and sporadic hepatitis E in parts of Asia and Africa, where the disease is highly endemic. Genotype 2 sequences, first reported from an outbreak of hepatitis E in Mexico, have subsequently been reported from cases in western Africa. Genotype 3 HEV, first identified in a few rare cases of locally acquired hepatitis E in the USA, has subsequently been reported from human cases in several industrialized countries in Europe, as well as in Asia-Pacific. Genotype 4 HEV has been found in sporadic cases with acute hepatitis from China, Japan, Taiwan, and Vietnam. All genotypes share at least one major serologically cross-reactive epitope and belong to a single serotype. Genotype 3 and 4 isolates of HEV appear to be somewhat less pathogenic in humans than those from genotypes 1 and 2. Although the human is considered as the natural host for HEV, antibodies to HEV or closely related viruses have been detected in primates and several other animal species.
HEV-1 is also linked to imported infections in several European countries (i.e., Spain, Finland, and France) and industrialized Asian countries like Japan that are isolated from patients with a history of traveling to endemic countries. HEV-1 and HEV-2 infections mostly affect developing countries. The infections by the two genotypes are responsible for the outbreaks in developing countries where the viruses are transmitted through drinking water supplies contaminated with human feces (e.g., after heavy rainfall or flood). The outbreaks were reported in refugee camps, military camps, and internally displaced persons camps with dense populations and poor sanitation.
| Conclusion|| |
We found the genotype 1F as the only genotype in this region during the outbreak on 2018, and further study is needed to know it better.
We would like to thank SlieaGen LLC and the Department of Microbiology of CMOSHMC for their assistance and help.
Financial support and sponsorship
This study was financially supported by SlieaGen LLC, Texas, USA.
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]