Flood Woes

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Floods are not only troublesome and life-wrecking – they are known to increase the transmission of the following: 

Water-borne diseases

Examples include typhoid, cholera, hepatitis A. These diseases are caused by drinking contaminated water. There is also an increased risk of infection through direct contact with contaminated water (not by drinking). These include wound infections, dermatitis, conjunctivitis, ear, nose and throat infections. However, these diseases are not epidemic-prone. Leptospirosis is one disease that can be contracted through the skin or mucous membranes (like the eye). It is transmitted through rodent urine, which can contaminate water during floods. 

Vector-borne diseases

Examples include malaria and dengue. The vector here is the mosquito, which tends to breed during floods.   During heavy rainfall, water accumulates in even more places. Stagnant water encourages mosquitoes to breed, especially when the flood waters recede.  Usually, malaria epidemics occur around six to eight weeks after a flood. The risk of mosquito disease outbreaks is also enhanced because of human behavioural changes. If you are displaced and forced to sleep outside or in tents without mosquito nets or aerosols, the risk of getting bitten is a lot higher.  

Whenever we get the usual flooding, if our source of drinking water is not contaminated (such as reservoirs, streams, wells and so on), then the risk of infection is low.  However, if there is significant population displacement and/or if our water sources are compromised, then the risk of infection is high, especially when we have no access to fresh sources of water. 

A major flood in West Bengal, India, in 1998, for example led to a huge cholera epidemic. Another one in Mozambique in 2000 saw an increase in the incidence of diarrhoea. A cyclone and flooding in Mauritius in 1980 led to an outbreak of typhoid. 

Floating animal carcasses can contaminate usable water, especially if the animals were diseased in the first place. (Note: rodent urine and leptospirosis.) Dead bodies also discharge faeces that may contain micro-organisms which can pollute the water. 

A flood worker who handles human corpses, may be at risk of contracting tuberculosis, hepatitis B and C, HIV, and certain diarrhoeas. Exposure to viruses can occur due to direct contact with blood or body fluids, for example, if blood from a corpse splashes the  eye or a splinter of bone punctures the skin. 

However, according to the World Health Organization (WHO), there is no evidence that human corpses pose a risk of disease epidemics to other humans who do not handle corpses after natural disasters. This is because most bacterial or viral agents do not survive long in the human body after death.   In fact, the greatest source of infections is likely to be the human survivors! Overcrowding and being forced to share space with an infectious person will certainly increase the risk. Nevertheless, HIV can survive up to six days in a dead body. 

Leptospirosis  

Leptospirosis is caused by the bacteria Leptospira. Outbreaks are usually caused by exposure to water contaminated with the urine of infected animals, such as rodents, cattle, pigs, horses, dogs and wild animals.   Humans become infected through urine-contaminated water, food, or soil, either by drinking/eating or skin/mucous membrane contact. It is not spread from human to human. Symptoms include high fever, a severe headache, chills, muscle ache, vomiting, jaundice, red eyes, abdominal pain, diarrhoea, and rash. If not treated, one can develop kidney failure, meningitis (brain and spinal cord inflammation), liver failure, breathing problems and even death.  Some patients don’t develop symptoms at all.  Leptospirosis can be treated with antibiotics such as doxycycline and penicillin. 

What measures to take if one is living in a flood-prone area?  

Besides moving to a safer area, drink only boiled chlorinated water. Don’t drink water from rivers or wells after a flood. Make sure food is prepared with the same water. Wash  hands after touching contaminated water.  Since malaria only happens six to eight weeks after a flood, after experiencing one, one should use aerosols to kill mosquitoes. Sleep under a mosquito net. This will also help prevent dengue.