Flooding and public health

CEBU, Philippines - A 2010 report of the World Health Organization already warned of increasing frequency and intensity of floods and its impact to public health.

“Floods contaminate freshwater supplies, heighten the risk of water-borne diseases, and create breeding grounds for disease-carrying insects such as mosquitoes. These also cause drowning and physical injuries, damage to homes and disruption in the supply of medical and health services,” WHO announced.

Patterns of infection

According to WHO, “climactic conditions strongly affect water-borne diseases and diseases transmitted through insects, snails or other cold-blooded animals.”

Changes in climate are likely to lengthen the transmission seasons of important vector-borne diseases and to alter their geographic range, it added. For example, climate change is projected to widen significantly the area of China where the snail-borne disease schistosomiasis occurs.

Malaria is strongly influenced by climate. Transmitted by Anopheles mosquitoes, malaria kills almost one million people every year – mainly African children under five years old. As for the Aedes mosquito vector of dengue, it is also highly sensitive to climate conditions in countries like the Philippines.

“Studies suggest that climate change could expose an additional two billion people to dengue transmission by 2080,” WHO confirmed.

Most at risk

The report cum warning also printed out that all populations will be affected by climate change, but some are more vulnerable than others. “People living in small island-developing states and other coastal regions, megacities, and mountainous and polar regions are particularly vulnerable.”

“Children – in particular, children living in poor countries – are among the most vulnerable to the resulting health risks and will be exposed longer to the health consequences,” the risk group was clearly identified. “The health effects are also expected to be more severe for elderly people and people with infirmities or pre-existing medical conditions.”

Areas with weak health infrastructure – mostly in developing countries like the Philippines – will be the “least able to cope without assistance to prepare and respond.”

WHO response

Many policies and individual choices have the potential to reduce greenhouse gas emissions and produce major health co-benefits. WHO gave as an example the promotion of the safe use of public transportation and activities such as cycling or walking as alternatives to using private vehicles. Strict observance of such practices is seen to dramatically reduce carbon dioxide emissions and improve health.

In 2009, the World Health Assembly endorsed a new WHO workplan on climate change and health which includes:

•Advocacy – to raise awareness that climate change is a fundamental threat to human health

•Partnerships – to coordinate with partner agencies within the UN system, and ensure that health is properly represented in the climate change agenda

•Science and evidence – to coordinate reviews of the scientific evidence on the links between climate change and health, and develop a global research agenda

•Health system strengthening – to assist countries in assessing health vulnerabilities and build capacity to reduce health vulnerability to climate change.

PHL response

From the looks of it, the Philippines, which is one of the areas most vulnerable to the ill effects of climate change, is being swept away by the undertow of its very own nonchalance. Continued cutting down of trees has slowly deactivated our forests’ function as a natural sponge. That’s why an “unexpected” volume of surface runoffs, aside from water released by dams, have flowed to tributaries and major rivers carrying with it silt and debris, thereby making the river banks swollen. The aftermath is widespread flooding, hitting communities that lie in floodways. What’s expected to follow is a surge of leptospirosis and dengue cases. That’s why the Department of Health has already distributed anti-lepto medicines to people who have been exposed to floodwaters. Still, some refused to leave their settlements. Never mind if they are now making the lagoon around them their 10-hectare lavatory.

Other health risks

Standing water also poses the following health risks: drowning and injuries or trauma, and hypothermia. Tetanus is not common after injury from flooding, and mass tetanus vaccination programs are not indicated. However, tetanus boosters may be indicated for previously vaccinated people who sustain open wounds or for other injured people depending on their tetanus immunization history.

Hypothermia may also be a problem, particularly in children, if trapped in floodwaters for lengthy periods. There may also be an increased risk of respiratory tract infections due to exposure (loss of shelter, exposure to floodwaters and rain).

Contrary to common belief, there is no evidence that corpses pose a risk of disease epidemics after natural disasters. Most agents do not survive long in the human body after death (with the exception of HIV – which can be up to six days) and the source of acute infections is more likely to be the survivors. Human remains only pose health risks in a few special cases requiring specific precautions such as deaths from cholera or hemorrhagic fevers.

However, WHO stressed that workers who routinely handle corpses may have a risk of contracting tuberculosis, blood-borne viruses (such as Hepatitis B/C and HIV) and gastrointestinal infections such as rotavirus diarrhea, salmonellosis, E.coli, typhoid/paratyphoid fever, Hepa A, shigellosis (bacillary dysentery or Marlow Syndrome), and cholera.