Throughout history, disasters, both natural and man-made, have a strong relationship with disease outbreaks. This is often related to the displacement of people and has been known since the age of Pericles and the plague of Athens in Ancient Greece during the Peloponnesian wars. This has played out again and again since then, including in major wars, but this association is now seen commonly after natural disasters like floods, tsunami, volcanic eruptions, drought and earthquakes.
The disaster in Tamil Nadu due to the recent rains and floods is already seeing an outbreak of various diseases. The risk and magnitude of any outbreak can be assessed based on the diseases that are pre-existent in the community, the existing infrastructure, nutrition and health status, ability to restore safe water and drainage and availability of health care. Given that Chennai and other parts have seen tremendous waterlogging and people have been wading through water over several days, the number of water-borne, vector-borne, person-to-person communicable diseases and those related to the disaster, are those that the state government, NGOs and volunteers working in the field need to worry about.
Types of diseases likely to surface
Firstly, water-borne diseases that are likely to surface in Chennai now include viral gastro enteritis, cholera, typhoid, hepatitis A and E, leptospirosis among others. If people remember, there was a spike in cases of leptospirosis in Mumbai after the 2005 floods. Waterborne diseases can be mitigated here by ensuring that the water is drained out as quickly as possible in the city and safe drinking water is provided on a war footing.
Secondly, vector-borne diseases that are likely to emerge include dengue and malaria. Others like West Nile virus are also possible. These are primarily mosquito-borne, so stagnant water is a perfect breeding ground. Draining inundated areas in Chennai is key to control and moving people out of such areas is also helpful.
Lastly, person-to-person communicable diseases are usually related to overcrowding in close quarters. Diseases like influenza and upper respiratory infections tend to spread faster this way. This was, in fact, the leading cause of death in those displaced by the 2004 tsunami in Aceh and the 2005 earthquake in Pakistan. Measles outbreaks have also been documented in these conditions. In Chennai, there are reports of chicken pox outbreak in a relief camp. This also needs to be addressed quickly.
Other diseases are related to the disaster itself, and this includes tetanus, skin problems, including allergies and fungal infections. There have been rumours about dead bodies and the risk of transmission of diseases - these are overhyped, and there is yet to be any documented outbreak in the setting of the floods.
Prevention and tips on health safety
Prevention and mitigation of these diseases, in Chennai, Cuddalore and other areas, needs a multi-pronged strategy. Obviously, drainage of the water and establishment of safe water and food services is key. People should not remain marooned, but staying too long in relief camps puts them at risk for other problems. The earlier the situation improves and the earlier that people can return home, the safer it is from the infection point of view. People should avoid wading in water, if feasible.
Safe water can be achieved by boiling water for a full minute. If there is visible contamination, bleach (1/4 to 1/8 teaspoon to a gallon or 16 cups of water) can be useful. Reverse osmosis systems are also an option. Food safety is key, and the role of food handlers in the propagation of diseases is often forgotten. Aid workers should stay away if sick, and should wear gloves when handling food. Vaccination against tetanus, typhoid and influenza seems prudent. Mosquito prevention measures are useful, but these need to be used through the day.
Don’t medicate unnecessarily
At this point, abuse of medications, especially antibiotics, is a problem. Most patients do not need any. Establishment of appropriate primary care system with doctors trained in disaster-related disease management will go a long way in containing the situation. Studies have suggested that a single dose of doxycycline may be an option in reducing the risk of leptospirosis in those wading through water. It is only required for those with infections like typhoid. In general, the alarm symptoms that require immediate medical attention include:
1. Diarrhoea/vomiting and not passing urine
2. Fever with shaking chills
3. Jaundice
4. Fever lasting more than 3 days
5. Breathing difficulty and shortness of breath
6. Illness in people whose immune system is not normal- like kidney failure, transplant
Dr Subramanian Swaminathan is MD AB Infectious Diseases, Consultant, Global Hospital
