Dec. 30, 2004
MSNBC
WATER-BORNE DISEASES
The major risk associated with flooding is the contamination of drinking-water facilities. For example, a 1971 typhoon in Truk District, Trust Territories of the Pacific led to an outbreak of balantidiasis, an intestinal protozoan following the contamination of groundwater with pig feces. A cyclone and flooding in Mauritius in 1980 led to an outbreak of typhoid fever.
There is an increased risk of infection of water-borne diseases contracted through direct contact with polluted waters, such as wound infections, dermatitis, conjunctivitis, and ear, nose and throat infections. However, these diseases are not epidemic-prone.
The only epidemic-prone infection which can be transmitted directly from contaminated water is leptospirosis, a zoonotic bacterial disease. Transmission occurs through contact of the skin and mucous membranes with water, damp soil or vegetation or mud contaminated with rodent urine. The occurrence of flooding after heavy rainfall facilitates the spread of the organism due to the proliferation of rodents which shed large amounts of leptospires in their urine. Outbreaks of leptospirosis occurred in Brazil (1983, 1988 and 1996), in Nicaragua (1995), Krasnodar region, Russian Federation (1997), Santa Fe, USA (1998) Orissa, India (1999) and Thailand (2000).
Of the 14 major floods which occurred globally between 1970 and 1994, only one led to a major diarrhoeal disease outbreak - in Sudan, 1980. This was probably because the flood was complicated by population displacement.
RISK FROM VECTOR-BORNE DISEASE
Floods may indirectly lead to an increase in vector-borne diseases through the expansion in the number and range of vector habitats. Standing water caused by heavy rainfall or overflow of rivers can act as breeding sites for mosquitoes, increasing the possibility of infections such as dengue, malaria and West Nile fever. Flooding may initially flush out mosquito breeding, but it comes back when the waters recede. The lag time is usually around 6-8 weeks before the onset of a malaria epidemic.
Malaria epidemics in the wake of flooding are a well-known phenomenon in malaria-endemic areas world-wide. For instance, an earthquake and subsequent flooding in Costa Rica's Atlantic region in 1991 and flooding on the Dominican Republic in 2004 led to malaria outbreaks.
West Nile Fever has resurged in Europe subsequent to heavy rains and flooding, with outbreaks in Romania in 1996-97, in the Czech Republic in 1997 and Italy in 1998.
The risk of outbreaks is greatly increased by complicating factors, such as changes in human behavior (increased exposure to mosquitoes while sleeping outside, a temporary pause in disease control activities, overcrowding), or changes in the habitat which promote mosquito breeding (landslide, deforestation, river damming, and rerouting).
RISK FROM CORPSES
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) 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 haemorrhagic fevers.
Workers who routinely handle corpses may have a risk of contracting tuberculosis, bloodborne viruses (such as Hepatitis B/C and HIV), and gastrointestinal infections (such as rotavirus diarrhoea, salmonellosis, E. coli, typhoid/paratyphoid fevers, hepatitis A, shigellosis and cholera).
http://www.msnbc.com/modules/interactive.asp?id=/d/ip/flood_disease_041229/data.js&navid=6758618&cp1=1