Health risks related to Tsunami disaster

A massive earthquake of 9.0 magnitude on the Richter scale struck off the west coast of northern Sumatra on Sunday morning , December 26 . The quake triggered giant tidal waves that left a trail of death and destruction in South and South-East Asia. The waves hit the coasts of India, Srilanka, Indonesia, Malaysia, Thailand, Maldives, Myanmar, Bangladesh and as far as east Africa. More than 150,000 people have been killed including 9,500 in India. Body count in the tsunami- hit areas threatens to rise as chances of communicable diseases have increased in the affected areas according to a World Health Organisation assessment.

World Health Organisation: click

The coastal residents who have survived Tsunami face a number of serious health threats. Some of the health risks are as follows:

Psychological trauma: Water borne diseases: Vector borne diseases: Cadaver related disease; Other disease conditions.

Psychological trauma:

Long term effect on psychological health may perhaps be more important than illness or injury. For most people the emotional trauma will remain for a long time. Many survivors are likely to face post -traumatic stress syndrome after such a narrow escape from death. (Effects of traumatic stress in a disaster situation: click)

Water borne diseases:
Floodwaters often contaminate food and drinking water. Some of the water borne diseases include cholera, leptospirosis, dysentery, shigellosis, typhoid fever and hepatitis

Cholera:(Asiatic or epidemic cholera)-

Severe acute gastrointestinal infection caused by Vibrio cholerae. The incubation period is from a few hours to 5 days. The disease begins with sudden onset of profuse, watery diarrhea consisting of large volumes of clear fluid with flecks of mucus (rice water stool).
Cholera vibrios multiply in the lumen of the small bowel and are non-invasive. They secrete a powerful exotoxin (enterotoxin) which stimulates the adenyl cyclase-adenisine monophosphate pathway of the mucosa resulting in outpouring of normal alkaline small bowel fluid . This causes severe dehydration, anuria, acidosis and shock. Loss of potassium ion may lead to cardiac complications and circulatory failure. In extreme cases Cholera is a rapidly fatal condition. The patient may become hypotensive within one hour of the onset of symptoms and may die within few hours if no treatment is provided.

Leptospirosis:

The Andaman and Nicobar Islands is among the worst affected in the tsunami attack and there is a serious risk of an outbreak of Weil's Syndrome (locally known as Andaman fever). The disease often occurs after natural catastrophes like tsunami and has been widely reported following floods and cyclones. ( Andaman fever back? by D. Chaki-The Statesman. Thurs 30th Dec. Pg.4)
Leptospirosis is caused by the spirochete Leptospira interrogans. More severe cases of Leptospirosis are called Weil's syndrome or icterohemorrhagic syndrome.
The disease is transmitted by rodents to farm animals and human beings. The organisms spread through contact with urine from infected animals and contaminated water or mud. Warm and moist environments and marshy surroundings favour survival of the spirochetes. These are exactly the conditions reported from the islands. The organisms enter the body through cuts or other skin damage or through mucous membranes. Farmers, sewer workers, fishermen, dairy farmers or military personnels have been the primary victims.
Incubation period is about 7 to 12 days. The symptoms include high fever, headache, chill, muscle aches and vomiting. Eventually, hepatic failure, renal failure, myocarditis and shock may lead to death. Early detection of the disease is the key to saving lives.
Blood samples are tested to detect antibodies against Leptospira interrogans.

Shigellosis : (Bacillary dysentery):

In epidemics Shigella dysenteriae Type I organisms are responsible for life threatening dysentery . It is highly contagious. Infection is transmitted from the faeces of an infected person or by drinking contaminated water. The incubation period is between 2 to 5 days. The symptoms include bloody diarrrhea, fever, abdominal pain and tenesmus. Diffuse involvement of the colon is associated with high fever, chills, toxemia and shock. The organism invade and multiply in the epithelium and and lamina propria of the terminal ileum and colon. The ulcerated mucosa is covered by pseudomembrane consisting of necrotic mucosa, neutrophils, fibrins and erythrocytes. The shiga toxin like cholera toxin and E. coli enterotoxin induces hypersecretion of fluid and electrolyte from the mucosa of the terminal ileum. Water and electrolyte balance must be maintained to prevent dehydration, prostration and impaired mental status.

Vector borne diseases:

South East Asia is endemic for malaria and dengue fever. Tsunami has left pools of standing water which provides breeding ground for mosquitoes. The risk of outbreaks is greatly increased due to exposure to mosquitoes while sleeping outside and in temporary shelters.

Malaria: (uncomplicated or severe):
Malaria is caused by one of the four types of protozoa : Plasmodium vivax, P malariae, P.ovale, P. falciparum. These are transmitted only by the bite of female Anopheles mosquitoes and humans are the only natural reservoirs. The incubation period is between 7 to 30 days. Symptoms include high fever, chills, sweats, headaches, nausea, vomiting , body aches & malaise. Diagnosis of malaria depends on demonstration of parasites in appropriately stained thick smears of peripheral blood.
Severe malaria is caused by infection with Plasmodium falciparum. Clinically complicated malaria presents with life threatening conditions which include coma, severe anaemia, renal failure, respiratory distress, hypoglycaemia, shock and convulsion . Cerebral malaria should be considered where there is encephalopathy in the presence of malaria parasites.

Dengue:
Dengue virus infection is transmitted to man by infected Aedes mosquitoes. Incubation period is 5 to 6 days.
Patients present with flulike symptoms , intense backache, myalgia, generalized pain including orbital and periarticular areas, nausea and vomiting. Dengue haemorrhagic fever is common children and is characterized by the acute onset of fever , bleeding (petechiae, ecchymoses, epistaxis, melaena) and proceeds to acute circulatory failure.

Typhoid fever:
Viral hepatitis A: click

Cadaver related disease:

It has been reported that in natural disasters people die from trauma and are not likely to have epidemic causing infections. This indicates that corpses pose relatively little risk of outbreaks.

[Futher reading: 1. Infectious disease risk from dead bodies following natural disasters:click here (pdf)
2. Epidemics caused by dead bodies a disaster myth that does not want to die: click here (pdf)]

Other conditions include:

Tetanus and infection of open wounds. click here
Toxic chemicals in the environment and contamination of food or water: This may be due to flooding and destruction of pesticide ware houses gasoline tanks and waste disposal sites. This may result in immediate health risk or may have long term health consequences.
Respiratory diseases: Homeless survivors in overcrowded shelters are prone to flulike symptoms , measles,respiratory infections and pneumonia. The very young and old people are particularly susceptible.
Hypothermia: This is particularly a problem in small children who were trapped in water for long periods.