Disease Prevention
Malaria
Malaria is a common and life-threatening disease in many tropical and subtropical countries. It is an acute febrile illness transmitted by Anopheles mosquito’s, which bite mainly between sunset and sunrise. There is no vaccination available, so prevention consists of a combination of preventive medication (profylaxis) of anti-malaria tablets and avoidance of mosquito bites (e.g. use of bednet and insect repellent). Avoiding mosquito bites remains the cornerstone of protection against malaria.DO NOT GET BITTEN!
- Avoid bites at all times in all malaria risk areas.
- Cover up with long sleeves, trousers, socks and shoes (90% of mosquito bites occur below the knees!).
- Apply DEET (diethylmetatoluamide) insect repellent to exposed skin.
- Only sleep in air-conditioned or screened accommodation or carry an insecticide-impregnated bed net - and sleep under it!
- the risk of contracting malaria
- prevailing species of malaria parasites in the area
- level and spread of drug resistance reported from the area
- possible side effects of the tablets.
Malaria chemoprophylaxis kill the malaria parasite before the traveler becomes clinically ill. They act mostly on the parasites in the blood phase, either immediately after an infected bite, or when the parasites exit the liver at the end of the ‘incubation period’.
Chemoprophylaxis must therefore be commenced before entering the malaria area, to ensure that protective drug levels are reached and that the drugs are tolerated. Likewise prophylaxis have to be continued for 4 weeks after leaving the area to ensure eradication of parasites still emerging from the liver. Only the malaria profylaxe Malarone®, which acts on the liver stage of the parasites, can be stopped seven days after leaving the malaria area.
No drug or bite prevention method is 100% effective, but chosen and applied well, the combination can provide 90% protection against malaria illness and death. It has been shown that even if illness does occur, the likelihood of cerebral malaria is diminished and the chance of death reduced significantly.
No drug is completely without side effects. The decision whether to use preventive drugs or not should be based on the relative malaria risk in the area to be visited, any pre-existing disease or chronic medication the traveler may have or use, the potential side effects and cost of the available appropriate anti-malaria drugs.
Both personal protection methods and anti-malaria medications are important, and neither should be neglected at the expense of the other !
Links:
CDC - Malaria
WHO - Malaria
Dengue
There is a high incidence of Dengue in the Caribbean and other (sub-)tropical areas.
Transmission occurs from the bite of an infected Aedes aegypti (rarely Aedes albopictus) mosquito. Mosquitoes first become infected with dengue virus by feeding on the blood of a dengue-infected person. After the virus replicates for 8–12 days in the mosquito, the mosquito can transmit dengue virus to many other people.
The risk of being bitten is highest during the early morning, several hours after daybreak, and in the late afternoon several hours before sunset, because the female mosquito typically feeds (bites) during these hours. However, mosquitoes may feed at any time during the day
This is a female Aedes aegypti mosquito engorged with blood while feeding. Dengue viruses are transmitted during the feeding process.
Preventive Measures for Travelers
- Neither vaccine nor drugs for preventing Dengue infection do exist.
- Travelers should be advised to take measures to avoid being bitten by Aedes mosquitoes.
- Select accommodations with well-screened windows or air-conditioning when possible. Aedes mosquitoes typically live indoors and are often found in dark, cool places such as in closets, under beds, behind curtains, and in bathrooms. A traveler should be advised to use insecticides to get rid of mosquitoes in these areas.
- Wear light colored clothing adequately covers the arms and legs, especially during the early morning and late afternoon.
- Apply insect repellent to both skin and clothing (e.g., permethrin). The most effective repellents contain DEET (N,N-diethylmetatoluamide).
- Empty and clean or cover any standing water that can be mosquito-breeding sites in your accommodation (e.g., water storage barrels).
Link: CDC - Dengue
Yellow fever
Yellow fever is a viral disease transmitted by the bites of mosquitoes (Aedes Aegypti) in tropical Africa and in the forests of South America. The mosquito bites during the daylight hours.
The virus causes sudden onset of fever, four days after the bite. Most cases are mild, last less than a week, and the person makes a full recovery. Sometimes it is more serious. The liver may be damaged leading to jaundice - a yellowish tinge to the skin. Hence the name 'yellow' fever. It may cause joint pain and vomiting. Eventually the clotting system fails and bleeding occurs from the nose, gums, stomach and skin. Up to ten percent of sufferers will die 7 to 10 days after the onset of the illness.
There is no treatment for the disease “yellow fever”.
Travelers immunized against yellow fever are issued with an internationally recognized vaccination certificate for inspection by immigration officials. The international health regulations concerning yellow fever are unequivocal, and unvaccinated travelers may face denial of entry, or even quarantine in certain circumstances.This strict control of yellow fever vaccinations is maintained to:
- protect individual travelers who may be exposed to yellow fever infection. As yellow fever is frequently fatal, vaccination is recommended for all travelers visiting areas where the risk of exposure is high.
- protect countries from the risk of importing yellow fever virus. This is mandatory vaccination and required for entry of countries or areas concerned.
Porto Medico is a designated “Yellow Fever Vaccination Center”.
Link: CDC - Yellow Fever
Hepatitis A
Hepatitis A is an acute contagious liver disease caused by the Hepatitis A virus, lasting from a few weeks to several months. It is mainly spread by the fecal-oral route, usually via contaminated food and water. Although the disease is not usually fatal, it can cause a prolonged, debilitating and unpleasant illness. Persons of high socio-economic status are often susceptible.
Vaccination should start 4 weeks before departure if possible. A booster dose is given 6 – 24 months later to provide protection for at least 10 years. Hepatitis A vaccination is recommended for all children starting at age 1 year, travelers to certain countries, and others at risk.
Hepatitis A is the most common vaccine preventable infection among travelers.
Link: CDC- Hepatitis A
Hepatitis B
Hepatitis B virus (HBV) is transmitted from person to person via infected blood and other body fluids. Important exposure includes unprotected sexual contact, transfusion of unscreened blood, exposure to unsterilized needles, body piercing, tattooing and contact with blood or open wounds. Hepatitis B infection occurs worldwide.
The liver infection may last from a few weeks to a serious long term (chronic) illness that can lead to liver disease or liver cancer. Hepatitis B vaccination is recommended for all infants, older children and adolescents who were not vaccinated previously, and adults at risk for HBV infection.
Three doses of vaccine constitute the complete series; the first two are usually given one month apart, with a third dose 6 months later.
A rapid schedule is day 0, day 7 and day 21. Recommended is a 4th dose after one year.
Immunization provides protection for at least 15 years.
Link: CDC - Hepatitis B
Influenza
Influenza viruses evolve rapidly, changing their antigenic characteristics, so that vaccines need to be modified each year to be effective against currently circulating influenza strains. Influenza virus type A (H1N1 and H3N2) cause most of the widespread influenza epidemics. Transmission is by direct contact with droplets disseminated by unprotected cough and sneezing and contamination of hands.
Influenza is a seasonal disease occurring in winter; in the northern hemisphere from November to March and in the southern hemisphere from April to September. In tropical areas there is no clear seasonal pattern, and influenza may occur at any time of the year.
“Seasonal flu vaccination” is before the start of the influenza season.
WHO recommends a Flu shot to prevent influenza for persons with:- age > 65 years
- Diabetes Mellitus
- Chronic Pulmonary illness
- Cardio-vascular illness
- Renal dysfunction
- Immunosuppression due to medication, HIV etc.
- Contacts with high risk persons
The seasonal flu vaccine is not to protect against the Influenza A Novel H1N1 flu, also called “Mexican flu” or “Swine flu”.
Link: CDC - Influenza