2013 Vol.1 Iss.1 Vietnam Journal of Public Health - www.vjph.org 5 COMMENTARY
Climate Change Impacts on Public Health in Vietnam: Unravelling the Black Box
Raouf Naguib1, Quynh T Nguyen1, Nghia T Ton2and Hubert Jenny3
1 Biomedical Computing and Engineering Technologies Applied Research Group (BIOCORE), Coventry University, UK 2 Environmental Health Unit, World Health Organization, Vietnam Office, Hanoi, Vietnam
3 Urban and Water Division, Vietnam Resident Mission, Asian Development Bank
Climate change is considered by many to be one of the most significant global health threats of the 21stcentury, and climatic risks are proving to be higher for developing countries. Vietnam, in particular, was listed amongst the 12 low- and middle-income countries at the highest risk of climate change and the most threatened by sea level rise1. It has been projected through a recent study by Hu et al that both Ho Chi Minh City and Hai Phong will be the 5thand 10thtop cities in the world, respectively, in terms of population exposure to coastal flooding damage in 20702. The consequent disruption of climatic changes affects the Vietnamese population’s health through three main pathways:
CHANGES IN TEMPERATURES
● Air pollution concentration and distribution combined with exposure to ultraviolet radiation may result in the exacerbation of cardiovascular conditions, worsening of asthma/respiratory diseases, allergies or heat-related illnesses and even resulting in deaths. In Vietnam, evidence shows that strokes and ischemic heart disease are categorised as the top causes of mortality3.
● Shortages of raw and clean water due to long and severe summers are related to changes in the distribution of vector-borne and water-borne diseases. Viruses, fungi, parasites, protozoa and bacteria adapt to the changes in the environment and increase the mutation rates of different microorganisms5. In turn, the prevalence and the range of climate-sensitive diseases increase and become more severe, especially in the case of zoonotic diseases.
CHANGES IN SEA LEVELS
● Sea level rise (SLR) has a significant impact on water resources as excessive surface and ground water salinity intrusions reduce fresh water availability, with a further impact on the normal characteristics of coastal soil. From a public health perspective, reports from other countries show that cholera and diarrhoea incidences undergo direct increases due to SLR6.
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For example, some strains of Vibrio Cholerae, which breed and survive longer within environments with salinity levels ranging from 2.5ppt to 30ppt and require the Sodium ion (Na+) for growth, can be the direct cause of widespread cholera epidemics.
● Another side effect of SLR is the gradual but sustained erosion of coastal areas resulting in the displacement of populations. It has been projected that a SLR of 1m would result in as many as 7 million residents of the Mekong Delta region in Vietnam (out of 18 million) being displaced7. A consequential effect of such disruption can be reflected in the unexplained but prevalent occurrences of depression and anxiety which have been recently reported in Vietnam8.
CHANGES IN FOOD PRODUCTION
● Agricultural production can be reduced due to excessive heat, floods, droughts, storms and rise in sea level. The most severe case of paddy inundation so far occurred during the 1997 El Niño year when 607,524ha of the Mekong Delta region, which is at the heart of rice production in Vietnam, were flooded. In addition, a variety of sources have reported that approximately 1.7 million hectares, representing 42% of the paddy fields in the region, were affected by saltwater intrusion. These severe disruptions can have a considerable malnutrition effect on the vulnerable population who rely heavily on flood cycles to cultivate rice and other crops, especially in the Mekong Delta region9.
In Vietnam, the combined mortality and morbidity trends from communicable diseases in the period 1976-2007 decreased sharply; however, diseases such as diarrhoea and pneumonia were still classified in the top ten disease burdens during the same period3. In 2007, in particular, morbidity from influenza was the highest with the rate of 1,946.73 per 100,000 inhabitants, followed by acute bronchitis (1,166.25), diarrhoea (1,144.69), pneumonia (1,007) and dengue fever (118.79)4. It is worth noting that there was a sustained gradual increase in the prevalence of dengue fever in the 4-year period leading to 2007. Furthermore, statistics from the Ministry of Health reported that there were 54,457 new cases of smear positive pulmonary tuberculosis in that same year10. Concurrently, episodes of hand, foot and mouth disease (HFMD), first diagnosed in 2005, rapidly spread, reached their peak in 2008 and are still currently being recorded. Indeed there were 28,725 cumulative cases of HFMD reported in the last 2 years11. Another example of zoonotic effect is swine influenza viruses, especially H1N1, which became a global pandemic in 2009-2010 with the country currently still encountering cases of A/H1N1 mutations.
On the other hand, in relation to non-communicable diseases, the World Health Organization (WHO) reported that the percentage of mortality rate due to cardiovascular diseases was statistically highest, rating at 40% in 2008, followed by cancers (14%), chronic respiratory diseases (8%) and diabetes (3%)12. Noticeably, Vietnam was found to be the country with the highest occurrences of Chronic Obstructive Pulmonary Disease (COPD) in a study conducted by the WHO Regional COPD Working Group in 2003, based on 12 Pacific-Asian countries13. The prevalence of liver disease and osteoarthritis was also reported to be major causes of disease burden in that year14.
2013 Vol.1 Iss.1 Vietnam Journal of Public Health - www.vjph.org 7 With regard to other non-communicable diseases, especially mental disorders, it has been projected that approximately 12 million Vietnamese are in need of mental health services. As mentioned above, prevalent occurrences of depression and anxiety have recently been reported in Vietnam8.
According to the Vietnam Institute of Strategy and Policy on Natural Resources and Environment (ISPONRE), the overall average temperature in Vietnam by the end of the 21st century is projected to increase from a range of [1.1 - 1.9]oC to a range of [2.1 - 3.6]oC in comparison with a 19-year period from 198015. There is a clear indication that the country will not exceed the global warming projection of a 4oC increase. Nonetheless, since Vietnam is considered to be one of the most vulnerable countries to climate change, it is critical to mitigate the situation from all environmental protection aspects, such as emission controls, air quality improvement and water source protection. One such small but practical mitigation example is that of our collaboration with other international organizations, as well as with the Khanh Hoa Water Supply and Sewerage Company (KHAWASSCO) in Nha Trang province, to carry out a Geographical Information System (GIS)-based risk assessment in order to improve raw water management strategies.
Results from this study will assist KHAWASCCO in its water safety plan to project the level of water quality fluctuation in the Cai River during the dry and typhoon seasons and reduce catchment area contaminations arising from such climatic hazards.
In conclusion, although a very small proportion of studies have been conducted in developed countries on disease areas associated with climate change, none of these studies considered the direct correlations between the various extreme climatic events and consequential individual diseases16. Whilst the facts given above do not provide a holistic view of the disease burden across Vietnam and do not provide a direct correlation between climate change and public health incidences, nonetheless they outline the rampant climate change situation and possible consequential environmental health problems that the Vietnamese population is being faced with. The authors strongly advocate the need for longitudinal epidemiological studies in Vietnam to (1), define the problem, (2) to associate the climatic variabilities with changes in individual disease patterns, and (3) to mitigate such effects through the early deployment of preventive strategies. This pathway may be a long and tedious one, however uncovering the black box necessitates enduring a learning curve marred by many uncertainties.
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