Sep 5, 2010

Cleaning up after the flood

The challenge is motivating hygiene behaviour change among the flood-affected population

By Syed Ayub Qutub

The images of swathes of drowned dwellings in the current flood have triggered a childhood memory. My father was Base Commander PAF Pattanga outside Chittagong when the tidal bore struck there in September 1960. It was a huge effort to clean up our house afterwards. Indeed, it is crucial to de-contaminate water supplies and to restore sanitation and drainage systems before routine living can start again in the flooded areas. It is also essential to undertake 'targeted hygiene' within the dwelling. While the procedures are simple and not costly, it is a concern that knowledge of the appropriate practices may not be widespread among the flood-affected populations. This article calls for widespread sharing and extension of the best practices through the media and person-to-person communication.

Flood waters are often contaminated with sewage and other organic material such as animal faeces, rotting vegetation and so on. In our rural areas, the practice of open defecation is common. It was in fact the only option for many persons during the flood emergency phase. Therefore, it must be assumed that in the flooded districts, the water supply systems and houses are contaminated with human or animal pathogens (either bacteria or viruses).

Hand pumps and motorised pumps are the main source of water supply in Pakistan, while tap water reaches less than a quarter of the rural population and 60 percent of the urban dwellers. All the water sources have to be rehabilitated. Provincial departments along with UNICEF have made plans for disinfection of public water supply schemes and actually started the work at places. But householders have to be equipped with the knowledge and skills to de-contaminate the hundreds of thousands of hand-and motor-pumps, wells and tanks in their courtyards.

As the floods subside, a muddy deposit is left behind on floors, walls and furnishing, and other surfaces on which moulds can grow, especially in damp places inside dwellings. Germs deposited on these surfaces will gradually die out, but whereas some pathogens e.g. Campylobacter die rapidly, others such as norovirus and germs which cause cholera and typhoid can persist and remain infectious for days, weeks or even months. These organisms can be transferred from contaminated surfaces via hands directly into the mouth or onto food, or indirectly via hands into food.

It is not always clear whether the flood waters, the water supply or the muddy surfaces inside the houses are contaminated with pathogens or not. The basic advice is to assume that they all are and take rigorous hygiene precautions to prevent spread of infection in the home. On the other hand, given the many livelihood rehabilitation tasks facing each flood-affected household, it is also important to prioritise the elements of the clean-up work. The essential first steps for targeted hygiene are:

Maintaining Personal Hygiene;

Disinfecting the Water Supply; and

Disinfecting Critical Food Preparation Surfaces

Human hands are "critical control points" for transmission of infection, since they come into direct contact with known "portals of entry" for pathogens (mouth, nose and conjunctiva of the eyes). For pathogens such as norovirus the "infectious dose" (the number of virus particles needed to cause infection) can be very small (1-10 particles). That is why hand hygiene is so important.

The key times for hand washing with soap are:

Immediately after defecation;

Immediately after cleansing baby;

After clean-up activities associated with the flooding;

Before preparing and handling cooked/ready-to-eat food; and

Before eating food or feeding children.

Parents should stop children from playing with flood and stagnant waters. They should ensure that children wash their hands with soap before eating.

During the floods, life became very chaotic for many, and even very basic hygiene measures such as hand washing were not possible due to the lack of clean water. In a similar situation again, a very simple thing to do which can significantly reduce the risk of disease is to avoid putting fingers into the mouth.

The affected population may be advised to:

Boil water before drinking during the early recovery phase. Bringing water to a rolling boil kills pathogens effectively. A rolling boil is when the water is bubbling so hard that the bubbles keep coming up when the water is stirred. A holding period of 3-5 minutes will ensure that water is safe, except in situations where contamination with spore-forming bacteria, fungal or protozoal cysts or hepatitis virus is suspected, in which case 10 minutes is advised.

Start the disinfection procedure with the storage or source closest to the point of use, for example, water tanks before boreholes. Otherwise, water can become re-contaminated downstream.

Disinfect the home water tank with bleaching powder at the rate of 10 to 20 milligrams (mg) per 100 litres of tank volume. For example, 200 mg bleaching powder should be stirred until dissolved in a 10 litre bucket before adding the resulting chlorine solution to a 1000 litre tank. The minimum contact time is 30 minutes. It is preferable to add the chlorine solution at night for safe use the next morning.

Disinfect the borehole or hand-pump in a similar manner dissolving 50 grams (g) of bleaching powder in a 20 litre bucket. The thumb rule is 10 litres of chlorine solution per 5 running feet of pipe.

Disinfect an open or protected well by immersing an earthen pot (7-8 litres in volume) containing a mixture of bleaching powder and coarse sand (1:2 by weight) in it for slow chlorination.

Surface water sources require filtration to remove turbidity before disinfection. Turbid water should be filtered through a cotton cloth to remove any solid materials and treated with alum and bleaching powder, stored for at least 2 hours and then decanted or filtered through a clean cloth. For pre-treatment add 10g alum and 5g lime per 100 litre of turbid water. For disinfection of filtered surface water, apply 50 to 150 mg of chlorine solution per 100 litres of water.

For obtaining more detailed advice on the treatment of water, health service providers and civil society organisation may consult, "Emergency treatment of drinking water at point-of-use, WHO technical note for emergencies". It is available at:

The returning population may be advised to:

Ensure that food contact surfaces, such as countertops, chopping boards and cleaning cloths, eating utensils (cutlery and crockery) and hand contact surfaces (door handles, tap handles, stair rails etc.) are thoroughly cleaned to remove soiling using an appropriate disinfectant, such as bleach.

Throw away food or drink suspected of being contaminated. Rigorous standards of hygiene are important during handling and preparation of food during the early recovery phase.

Wash hands thoroughly with hot water and soap, especially after contact with floodwater or taking part in clean-up activities-and always before handling or eating food, or feeding children.

As life begins to return to normal, some subsequent measures include:

Hygienic cleaning of soft furnishings, clothing, linens and bedding;

Hygienic cleaning of laundry; and

General cleaning up inside the house.

For obtaining more detailed advice on hygienic cleaning of the home, health service providers may consult Home hygiene in developing countries: prevention of infection in the home and peri-domestic settings - Urdu edition (2009), International Scientific Forum on Home Hygiene. It is available at

The early recovery and rehabilitation measures described above entail little investment but offer potentially huge public health benefits. The challenge is motivating hygiene behaviour change among the flood-affected population. The terrible dislocation caused by the floods offers a window to introduce science-based public health information to change attitudes and behaviours. The mass media have great reach and several channels with the same messages can reinforce each other. But messages just heard or seen are easily forgotten. Just giving lectures about health risks is also likely to meet bemused resistance from people who are living in camps, tents or hostels, and planning to return to their homes. Health service providers and civil society organisations should gear up for the task of extension and demonstration of home hygiene and water safety practices in a respectful and participatory manner.

No comments:

Post a Comment