As the floods recede, beware of three types of diseases “lining up on shore”!

Author: Zhang Yaning, Peking Union Medical College Hospital

Reviewer: Huang Jing, Chief Physician, Peking Union Medical College Hospital

Since August, the seven major river basins in my country have entered the main flood season. As the saying goes, "After a major disaster, there will be a major epidemic", which means that after a major natural disaster, various infectious diseases are likely to spread. Relevant research shows that since 2000, there have been 19 cases of epidemic outbreaks reported in the literature after flood disasters around the world, mainly three common diseases such as natural epidemic diseases, intestinal infectious diseases, and skin diseases. Among them, the most common infectious diseases in my country are infectious diarrhea, dysentery, and malaria.

Figure 1 Copyright image, no permission to reprint

1. Intestinal infectious diseases

1. Risk factors After floods, water supply systems are damaged, resulting in insufficient water supply and poor water quality. At the same time, food is scarce and food safety is difficult to guarantee. In addition, the original inherent discharge methods of sewage, garbage, and feces are damaged, which greatly increases the risk of environmental and water pollution. After the disaster, people can only live temporarily in temporary places provided by the government. The population is dense, the living places are crowded, and sanitation problems are prominent. These environmental factors, drinking water and food pollution factors are risk factors that promote intestinal infectious diseases.

Figure 2 Copyright image, no permission to reprint

2. Preventive measures

(1) Drinking water safety: When choosing drinking water, bottled water that meets hygiene standards is preferred. Whether tap water is drinkable depends on the advice of the local water company or government department. According to the advice, if tap water is drinkable, it should be released for at least 3 minutes and then boiled for 1 minute before drinking it for the first time. If tap water is not drinkable, water from temporary water treatment equipment can be selected. Well water that has been flooded should not be drunk in a hurry, nor can it be used for washing vegetables. It needs to be treated and disinfected before being used again, and then boiled for drinking.

Figure 3 Copyright image, no permission to reprint

(2) Food safety: Food that has been in direct contact with flood water and food that has changed in properties or smell should be discarded directly; if the refrigerator is out of power for more than 4 hours, it is recommended to discard the food inside. Food should be cooked thoroughly, raw and cooked food should be kept separate, and cold food should be eaten less or not. Spoiled, moldy or rotten food should not be eaten. Tableware should be cleaned and disinfected before use. Boiling disinfection is the first choice, and the boiling time should be more than 15 minutes. Disinfectants can also be used for soaking disinfection, such as soaking in 250-500mg/L chlorine-containing disinfectants for 10 minutes. After soaking in disinfectants, rinse with clean water. Pay attention to hand hygiene, and wash hands before and after meals.

Figure 4 Copyright image, no permission to reprint

Environmental sanitation: Thoroughly clean the indoor and outdoor environment, including clearing stagnant water and sludge, removing feces and garbage, and promptly disposing of animal carcasses. After cleaning and disinfection, relocation should be carried out. Strengthen the management of feces and garbage, do not urinate or defecate anywhere, do not build public toilets or poultry houses near water sources; put garbage in designated places and do not litter.

2. Natural Epidemic Diseases

1. Risk factors Heavy rains and floods cause the habitats of pathogen host animals such as rodents to change, and they move to higher places like humans. In this case, people have more opportunities to come into contact with vectors. At the same time, the environment is humid, sanitary conditions have deteriorated, the density of mosquitoes has greatly increased, and the living conditions of disaster victims are relatively simple, so the chance of being bitten by mosquitoes will also increase significantly.

2. Preventive measures

(1) Prevent and control mosquitoes and flies: Wear long-sleeved clothes and roll up trouser legs into socks to prevent mosquito bites; use mosquito and fly prevention facilities such as screen doors, screen windows, and mosquito nets; use mosquito coils, mosquito repellent sprays, fly swatters, and other mosquito and fly control measures.

(2) Rat prevention and extermination: Avoid close contact with rats or other wild animals to prevent bites; use highly effective and safe anticoagulant rodenticides to exterminate rats; search for dead rats promptly after extermination and bury or burn them in a centralized location; spray pesticides at the same time when exterminating rats to eliminate free fleas and other parasites that have left the rats’ bodies, thus eliminating both rats and insects; animal carcasses should be buried deeply and the soil should be compacted; wear masks and gloves to take protective measures when handling animal carcasses.

3. Skin diseases

1. Risk factors: Water pollution after flood disasters, long-term immersion can easily lead to immersion dermatitis; in summer, the temperature is high and the humidity is high. If you do not take a shower and change your underwear, shoes and socks in time after contact with polluted water, it is very easy to cause athlete's foot, perineum and thigh root eczema; at the same time, the body's resistance is generally reduced after the disaster, and the original skin disease is easy to relapse. In particular, the work intensity of disaster relief personnel is high, and they are immersed in water for a long time. The probability of skin diseases is much higher than that of disaster victims.

2. Preventive measures Prevent skin ulcers. Keep the skin clean and dry, and wipe sweat with a towel at any time. You can apply some prickly heat powder on the wrinkles of the skin. When working in the water, take a break every 1 to 2 hours, dry your feet, and expose them to the sun for a while. After each work, be sure to wash your feet and wear dry shoes. If you find that the skin on your feet is broken and has a tendency to worsen, you should temporarily stay out of the water if the situation permits. Try to wear long boots. People with foot skin diseases should go into the water less often.

Figure 5 Copyright image, no permission to reprint

In addition to the above measures to actively prevent infectious diseases, if you do feel unwell, you should seek medical attention in time. Especially patients with fever and diarrhea should seek medical help as soon as possible. If you or your family members have infectious diseases, you should follow the doctor's advice. Patients and close contacts when necessary should cooperate with the isolation of infectious diseases and take medication as required.

References

[1]WALIKA M, MOITINHO DE ALMEIDA M, CASTRO DELGADO R, et al. Outbreaks following natural disasters: a review of the literature[J]. Disaster Med Public Health Prep, 2023,17:e444.

[2] China Center for Disease Control and Prevention. Technical Guidelines for Monitoring Communicable Diseases and Public Health Emergencies in Flood Disasters [J/OL]. https://www.chinacdc.cn/yyrdgz/202408/t20240802_293755.html