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28 JUL 2017
Some South Asian countries carry a large part of the global burden of Hepatitis E virus (HEV), especially where water contamination and unsafe drinking water supplies linger.
Hepatitis A and E are waterborne. Photo: Shumon Ahmed / icddr,b
Although Bangladesh is not among the high burden countries for HEV, many urban and rural areas are fraught with water contamination, poor hygiene and sanitation. New evidence suggests that this is contributing to the spread of waterborne diseases, including HEV outbreaks.
A recent icddr,b study has shown that small HEV outbreaks can be detected through surveillance of diagnostic laboratories in urban Bangladesh. Furthermore, the study suggests that these outbreaks are being caused by poor water quality.
“We identified patients with detectable HEV-specific antibody in order to determine laboratory-confirmed hepatitis E cases,” says Dr Sazzad, associate scientist at icddr,b and principal author of the study published in the American Journal of Tropical Medicine and Hygiene.
Surveillance of diagnostic laboratories has shown to detect HEV outbreaks. Photo: Shumon Ahmed / icddr,b
“Our study has shown that the HEV affected people reported to have drunk impure water from household supplies or reported to have seen impurities in household water supply preceding illness onset,” he adds.
On this World Hepatitis Day, the World Health Organisation (WHO) reminds its member states to implement the first global health sector strategy on viral hepatitis and thus help countries to eliminate hepatitis.
Large water-borne outbreaks are frequently caused by HEV in Africa and Asia, according to WHO. To combat this, access to safe drinking water and sanitation is essential as it can dramatically reduce transmission of HEV.
Risk of jaundice in humans from animals
HEV can also be transmitted through contaminated food or water sources to humans and other animals or via a faecal–oral route within animal species or from animals to humans (zoonosis) through infectious body fluids.
An icddr,b study exploring zoonotic transmission of HEV in Bangladesh has found that people exposed to pigs can be at a higher risk of jaundice due to poor hygiene and waste disposal.
Poor hygiene and sanitation can increase the risk of jaundice. Photo: Arttu Manninen. CC BY-NC-ND 2.0
“Our study compared history of jaundice for those who handled pigs and those who did not. We found that those exposed to pigs were more likely to be affected with jaundice,” says Mr Najmul Haider, principal author of the study and former research investigator at icddr,b.
The researchers also conducted serological tests on pigs for HEV-specific antibodies, the presence of which in the serum (blood) of these animals indicates that those have been exposed to HEV. The findings indicate that these animals have been infected by HEV.
Waste disposal near water bodies contaminates the environment. Photo: Marufish. CC BY-SA 2.0
“Traditionally cooked meat is sufficient to kill the HEV. Our findings indicate that possibly poor hygiene and sanitation have increased the risk of jaundice for those exposed to the animals,” says Dr Sazzad, co-author of the study.
Towards eliminating hepatitis
Alongside improved sanitation and food safety, vaccination is one of ways to prevent hepatitis transmission, according to the WHO global strategy on viral hepatitis.
icddr,b has recently received a grant to conduct research on a HEV vaccine and pregnant women. In Bangladesh, existing evidence suggests that HEV may contribute significantly to maternal deaths in the country, where one in five maternal deaths can be attributed to jaundice caused by HEV.
The work undertaken by Dr Zaman’s team will contribute to reducing risk of such maternal deaths. Researchers anticipate that vaccinations coupled with improved sanitation and hygiene will help the move towards lowering the burden of viral hepatitis in Bangladesh altogether.