14 October 2005                                     Printable (PDF) version

 

Hurricane Stan in Central America and Mexico - Advice for relief workers and other travellers to affected regions

On October 4, Hurricane Stan made landfall in Veracruz, Mexico bringing sustained winds to the area and generating separate storms across southern Mexico and Central America [1, 2]. The heavy rainfall caused widespread and severe flooding and landslides affecting millions of people across Guatemala, El Salvador, Nicaragua, Costa Rica and Mexico.

The southern coast of Guatemala from Mexico to El Salvador has been affected, together with the highland departments of Quetzaltenango, Chimaltenango, Sacatepequez, Huehuetenango and the Atitlan area in Solola.

The whole of El Salvador is on red alert as a result of flooding and landslides. In addition, the Santa Ana (Ilamatepec) volcano in the department of Sonsonate erupted on 1 October forcing the evacuation of thousands of local residents.

Although Nicaragua has been less affected than its neighbouring countries, many communities in the departments of Leon, Chinandega and Granada have suffered the effects of the storms.

In Mexico the states of Chiapas, Hidalgo, Guerrero, Oaxaca, Puebla and Veracruz have experienced flooding. The highway between the resorts of Acapulco and Zihuantanejo is currently closed, and the Tecun Uman border crossing with Guatemala is closed.

Many communities in Costa Rica have suffered flooding and landslides.

Situation maps of the affected areas can be found on the ReliefWeb website.

Extensive damage to buildings has occurred and many roads have been washed out or are blocked due to landslides. Several hundred people have died and tens of thousands have been displaced from their homes with many evacuated into temporary shelters.  

Vaccination advice

• All travellers should be up to date with their routine immunisations including MMR, and BCG, particularly for work in refugee settings and for long-term stay.

• Tetanus: A booster is recommended if not received within the past 10 years. In the UK, when a tetanus booster is recommended the trivalent tetanus, diphtheria and polio vaccine, is the vaccine of choice. Tetanus is transmitted via wound contamination with the bacterium Clostridium tetani.

• Diphtheria: A booster is recommended within the past 10 years. Diphtheria can be transmitted by the respiratory route or following skin infection with Corynebacterium diphtheriae.

• Hepatitis A and typhoid immunisations are recommended. Both of these diseases are transmitted by the faecal-oral route.

• Hepatitis B: Persons involved with patient care or contact with bodily fluids should be vaccinated. Hepatitis B is transmitted by contact with bodily fluids or blood.

• Cholera: Cholera is generally a very low risk for travellers to Mexico and Central America. At this time, vaccination is recommended only for aid workers in refugee settings. Cholera is transmitted via the faecal-oral route.

• Rabies: Rabies vaccination before travel should be considered as adequate post-exposure treatment with rabies immune globulin and vaccine is not likely to be available. As rabies in resource-poor regions of the world is usually transmitted by the bite of an infected dog, avoidance of all dogs is necessary.

Travellers leaving at short notice are still recommended to seek appropriate vaccinations. Although full protection from vaccines may not be achieved prior to departure, a rising level of immunity will develop.

Travellers who are unable to obtain a full vaccination course prior to travel should attempt to complete the course overseas.  If this is not possible, they should take care in exercising precautions against the vaccine-preventable diseases.

Food and water advice

Flooding, stagnant water and contamination of the water supply are conducive to development of diseases such as salmonellosis, campylobacteriosis, shigellosis, cholera, hepatitis A and E, and intestinal parasites including Giardia, Cryptosporidium and amoeba.

Careful food and water hygiene precautions should be employed by travellers to the area.

• Reliable sources of bottled water may not be available and it may be necessary to use water sterilisation methods. Bringing water to a boil is the most reliable method, but this may not always be practical.  Using iodine or chlorine preparations to purify water are usually effective but protozoan parasites such as Cryptosporidium and Giardia are not always killed by these agents.  In these cases combining iodine or chlorine treatment with filtration of water using a portable water filter that has a filter size of 0.2 µm to 1.0 µm should be performed.

• Self treatment for diarrhoeal illness can be carried. This should include oral rehydration treatment taken with purified water, an anti-motility agent such as loperamide and a treatment course of ciprofloxacin (500mg twice daily for up to three days), in the absence of contraindications. Individuals with diarrhoea that is associated with fever or passing blood should seek prompt medical evaluation. Personal hygiene, including frequent hand washing, is essential.

 

Malaria and other vector borne diseases

 

• Malaria is a risk in the rural areas of Nicaragua and Mexico; in rural areas of Guatemala below 1,500 meters; in the Alajuela, Limon, Guanacaste, and Heredia provinces of Costa Rica, and in Santa Ana and Ahuachapan provinces, western El Salvador.

• The recommended chemoprophylaxis is chloroquine. Proguanil is a suitable alternative for those unable to take chloroquine.

• Chloroquine should be initiated one week before travel, taken during travel and continued for four weeks after leaving the malarious areas.

• Specific details about malaria and each of the preventive regimens can be found on the NaTHNaC malaria information page.

Travellers are also advised to take insect bite avoidance measures to prevent malaria and other mosquito transmitted diseases such as dengue fever. Dengue fever may occur at increased frequency in the setting of poor environmental conditions with flooding and stagnant water. There is no vaccine against dengue fever.

Malaria is transmitted by Anopheles mosquitoes during the hours from dusk to dawn; whilst dengue is transmitted by Aedes mosquitoes during daylight hours.

Leptospirosis

• Leptospirosis is a zoonosis which infects a variety of wild and domesticated animals and is excreted in their urine.
• The disease is transmitted to humans if they are exposed to fresh or brackish water or moist soil contaminated by the urine of infected animals. Flooding may increase the risk of leptospirosis.
• Leptospira, the organism which causes the disease, usually enters the body through cut or abraded skin, mucous membranes, and conjunctivae. Ingestion of contaminated water can also lead to infection.
• Pre-exposure chemoprophylaxis of doxycycline 200 mg weekly, commencing 1 to 2 days prior to exposure, can be offered to those who may be unavoidably exposed to potentially contaminated water.
• Protective clothing should be worn by those who may be in direct contact with rodents, sewage or contaminated water. Cuts and grazes should be covered.

Other Disease Risks

Other possible infections that travellers may encounter directly after a flood are those transmitted through direct contact with polluted waters, such as wound and skin infections, eye infections such as conjunctivitis, and ear, nose and throat infections.  Vibrio vulnificus infection of wounds can occur when salt or brackish water contaminates them.  Crowding can lead to the risk of respiratory infections such as influenza, tuberculosis, and diphtheria.

Other health risks

The risk of injury after a natural disaster is high. Structural damage to buildings and roads, and interruptions to basic services all pose a risk. Landslides have blocked roads and are complicating the delivery of food, water and medicines.

There is severe damage to health facilities together with shortages of surgical supplies and medicines. Travellers should carry with them a personal first aid kit.

Risk from dead bodies

The infectious disease risk from handling dead bodies is low [3,4]. Workers should be psychologically prepared to work in such difficult situations.

Support for British Citizens

Persons planning to visit the affected areas should regularly consult the Foreign and Commonwealth Office for up-to-date security and safety advice.

References

1. United States Agency for International Development (USAID). Central America and Mexico - Floods: Fact Sheet #1 (FY 2006). 12 Oct 2005. Accessed 13 October 2005. www.reliefweb.int/rw/RWB.NSF/db900SID/EKOI-6H52MK?OpenDocument&rc=2&emid=TC-2005-000173-SLV 2. World Health Organization. Health Action in Crises. Hurricane Stan: Effects in Central America and Mexico. Accessed 13 October 2005. Available at: http://www.who.int/hac/en/3. Pan American Health Organization. Management of Dead Bodies in Disaster Situations. 2004. www.paho.org/English/dd/ped/ManejoCadaveres.htm4. Healing TD, Hoffman PN, Young SEJ. The infection hazard of human cadavers. CDR Review. 5:1-16, 1995. http://www.hpa.org.uk/cdr/archives/CDRreview/1995/cdrr0595.pdf

Links

Pan American Health Organization. Floods and landslides in Central America and Mexico: www.paho.org/english/DD/PED/ElSalvador-Floods1005.htm

World Health Organization. Floods - Technical Hazard Sheet - Natural Disaster Profile http://www.who.int/hac/techguidance/ems/floods/en/index.html

World Health Organization. Landslides - Technical Hazard Sheet - Natural Disaster Profile http://www.who.int/hac/techguidance/ems/landslides/en/index.html