Shelters

• It's easy for infectious disease to spread in a shelter. Lots of people are in close proximity during a time that challenges the ability practice normal hygiene, with strained bathroom facilities and diaper changes occurring in close quarters. Other challenges may include finding fresh clothes and laundry facilities and disposing of trash. It's not uncommon for people in group shelters to suffer diarrhea, nausea and respiratory illnesses, including colds.
  
  

Water Contamination

• Natural disasters that involve flooding can produce contaminated water that, in turn, can produce infectious disease, including fatal ones. Bacteria and parasites might infect water and breed within it. Sewage, animal feces and dead animals might also have fouled the water. Unfortunately, during times of flood, stranded people often find themselves forced to come in contact with such water, having to swim or wade through it to escape. Additionally, cleaning up after the disaster means handling items that may have soaked in contaminated water.
  
  

Risk

• In some areas, the risk of certain types of infectious disease after a natural disaster is less than in other areas. For instance, according to the Centers for Disease Control and Prevention, widespread infectious disease outbreaks after a hurricane are uncommon. Additionally, diseases such as cholera and typhoid are uncommon in developed countries. For these to break out after a disaster, the bacteria has to already be present in the area.
  
  

Diseases

• Parasites, viruses and bacteria all can cause illness after disasters. Parasites include those causing cryptosporidiosis--crypto, for short--and giardia, both diarrheal sicknesses. Bacterial illnesses include sickness from E. coli, leptospirosis, which can cause liver failure and kidney damage, and Legionnaires' disease, which reproduces in warm, stagnant water, the kind of water trapped in water systems that stand unused after natural disasters. Infectious viruses include the rotavirus, which causes acute diarrhea; the norovirus, which causes acute gastroenteritis; and the enterovirus, the second most common virus after the one that causes the cold.
  
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Prevention and Safeguards

• If you are unsure of the purity of water, it's best to assume it's unsafe. Water must be boiled or treated with iodine or chlorine before using it to clean, cook with or drink. Fully cook food and prepare it yourself. Wounds need to be cleaned as soon as possible and care should be taken to avoid new ones. Hygiene is one of the best infectious disease preventions. Use warm water when you can. Wash hands in water that has been disinfected or boiled, especially before handling food, after going to the bathroom and being in cleanup areas, or handling items that may have been exposed to contaminated water. If water is not available, use alcohol-based products to clean your hands. As well, be aware that standing water breeds mosquitoes, responsible for spreading diseases like the West Nile virus.