Malaria Prophylaxis

What Is Malariaanopheles
Which are the malaria symptoms
How do you know that you have malaria
Facts on malaria in Kenya
Countries at risk of transmission
What is malaria prophylaxis
Rationale for giving malaria prophylaxis
Populations most at risk of getting infected with malaria
Recommended drug regimens for malaria prophylaxis
Simplified facts on Malaria

 

1. What is Malaria?

This is a term which describes a disease syndrome caused by certain parasites called plasmodium infecting the human red blood cells. The parasites are introduced when an individual is bitten by a female anopheles mosquito which carries the parasite. The mosquito acquires these parasites after ingesting blood from an individual who happens to have been infected previously and the parasites multiplied becoming numerous in his blood. In other words an individual who gets infected with malaria parasites becomes a potential source of transmission to other people. This explains why it is easy to catch malaria if you stay in a place where majority of the people are continuously getting bitten by malaria transmitting mosquitoes. It is important to understand that after repeated infections partial immunity develops over the years. This allows the host to tolerate or to have the malaria parasite in their body and not suffer from malaria. This immunity is lost if there is no further infection for a couple of years. This means that people who lived for many years in a malaria endemic area and didn’t suffer malaria can be at risk if they leave that area and stay away for many years then later go back to the malaria endemic area. It also explains why visitors to a malaria endemic area are more at risk of becoming ill after mosquito bites which introduce malaria parasites while the usual area residents remain largely disease free.

2.Which Are The Malaria Symptoms

Malaria symptoms vary widely and range from uncomplicated disease in which case the symptoms are more obvious to severe and then complicated disease involving nonspecific clinical conditions which require expert intervention.

 

 

2.1 UNCOMPLICATED MALARIA
The symptoms include fever, shaking chills, headache, muscle aches and joint aches, body tiredness, a sensation of vomiting or vomiting itself may occur. It is important to note that fevers caused by malaria involve high body temperatures up to 40°C and higher.

 

2.2 COMPLICATED MALARIA

This happens when Individuals with severe malaria appear very sick. It may present in many different forms such as involvement of the red blood cells causing their massive destruction in a manner that leads to inadequate oxygen transfer to the body’s vital organs. This condition is called anemia. This is because the red blood cells are the ones involved in transferring oxygen, they are also the ones targeted and destroyed by the parasite. The temperatures may be high enough to cause seizures/ convulsions especially in children.  If the parasites clog the blood vessels which supply the brain this constitutes cerebral malaria which if not treated urgently will result in death. These are few examples of how severe malaria may present.
The body’s vital organs such as the kidneys, the heart and brain become involved and their functions get compromised. Complicated malaria may present as kidney failure in which case the affected person requires short term dialysis to support the kidney functions and help them to recover their usual physiological function. Kidney failure is a common cause of death due to malaria parasite infection. Complicated malaria may present as heart failure attributed to severe anemia. This form is again common among children below 5 years.

 

3. How Do You Know When You Have Malaria

If you travel to a place with known risks of getting infected with malaria it is important to understand that for most people symptoms begin 10days to 4weeks after infection, although one may feel sick as early as 8 days or up to one year later. Some malaria parasites can rest in the liver up to 4 years after one is bitten by an infected mosquito. When these parasites come out of the liver and begin to invade the red blood cells the person becomes sick with malaria.
Any traveler who becomes ill with a fever or a flu-like illness while travelling and up to one year after returning home should immediately seek professional medical care. When you visit the hospital or a clinic you should remember to tell your doctor that you had travelled to a malaria-risk area. This is extremely important because if the symptoms appear after going back to a country with no malaria risk the doctors in that country will not test your blood for malaria unless you tell them about your travel to the malaria – risk country. Failure to do so may delay the diagnosis of malaria and result in disease complication or death.

4. What Is Malaria Prophylaxis

Prophylaxis means prevention. Malaria prophylaxis describes the act of taking the recommended medicines in the recommended doses and period/duration with the aim of preventing malaria infection when and after travelling to malaria – risk place. Malaria prophylaxis should not replace the other prevention measures such as using mosquito nets and mosquito repellants to prevent mosquito bites. Other measures that are put in place to reduce mosquito access into residential houses and accommodation facilities in malaria – risk areas include fitting the windows with wire mesh, spraying the facilities with insecticides and providing suitable easy to use insecticide impregnated mosquito nets in the hotel rooms. Always be keen to ensure that you choose the accommodation facility with these measures whenever you travel.
It should be noted that no prophylactic regimen is 100%effective and advice on malaria prophylaxis changes frequently.

 

5. Rationale For Giving Malaria Prophylaxis

The disease is associated with serious illness and high death rates if not well treated. It is currently endemic in over 100 countries visited by 125 million travelers every year. There may be difficulties in accessing reliable medical care for travelers in certain situations such as war torn areas. Unique problems may be faced by travelers who return to a non endemic country.  Doctors in these countries may be unfamiliar with malaria treatment and this may lead to delayed diagnosis. Effective anti malarial medicines may not be registered/ available in countries which have no malaria risks. This implies that travelers who develop malaria after going back to these countries are at risk of not being able to access effective treatment. These limitations may result to severe and complicated malaria and high death rates.

 

6. Individuals Most At Risk Of Getting Infected With Malaria

Certain people are at a higher risk of getting infected compared to the general population. These include visitors from a non endemic to a malaria endemic area. Children below 5years even though living in a malaria endemic area are also at risk. Pregnant mothers are at risk as well regardless of the pre pregnancy malaria immunity status. Malaria in pregnancy is a common cause of pregnancy losses and premature deliveries.

 

7. Recommended Drug Regimens For Malaria Prophylaxis

7.1  General principles
Daily regimens should be started a day before arrival in the risk area (earlier if drug tolerance needs to be tested before departure) Weekly chloroquine should be started 1 week before arrival. Weekly mefloquine should preferably be started 2 to 3 weeks before departure to achieve higher pre travel blood levels and to allow side effects to be detected before travel so that possible alternatives can be considered. All prophylactic drugs should be taken with unfailing regularity for the duration of the stay in the malaria risk area and should be continued for 4 weeks after the last possible exposure.
NB: All the malaria prophylaxis regimen require a prescription. Do not buy these medicines without a prescription.

 

 

7.2 Anti malarial drugs used for prophylaxis in travelers
7.2.1 Atovaquone – proguanil combinations:  ( malarone)
Dosage regimen:  one dose daily

  1. 11- 20 kg 62.5 mg atovaquone plus 25 mg proguanil ( 1 pead. Tablet) daily
  2. 21 – 30kg 2 pediatric tablet daily
  3. 31 – 40 kg 3 pediatric tablets daily
  4. > 40kg 1 adult tablet ( 250mg atovaquone plus 100mg proguanil) daily

Duration of prophylaxis: start 1 day before departure and continue for 7 days after return
Use in special groups: pregnancy- not recommended,
Breast feeding – not recommended
Children – not recommended <11kg because of limited data

 

7.2.2 mefloquine :
Dosage regimen: 5mg/kg weekly
Adult dose : 1 tablet of 250mg weekly
Duration of prophylaxis: start at least 1 week ( preferably 2 to 3 weeks) before departure and continue for 4 weeks after return
Use in special groups: pregnancy- not recommended in first trimester,safe for breast feeding for use by breastfeeding mothers.
children: not recommended if < 5kg

 

7.2.3 Doxycycline
Dosage regimen: 1.5 mg/ kg daily
adult dose: 1 talet of 100mg daily
Duration of prophylaxis: start 1 day before departure and continue for
4 weeks after return
Use in special groups: pregnancy – contra indicated
breast feeding- contraindicated
children- contraindicated < 8kg yrs of age
Main contraindications: hypersensitivity to tetraycline, liver dysfunction           

comments: doxycycline makes the skin more susceptible to sunburn. People with sensitive skin should use a highly protective (UVA) sunscreen and avoid prolonged direct sunlight or switch to another drug. It should be taken with plenty of water to prevent esophagial irritation. Doxycycline may increase the risk of vaginal candida infections. Studies indicate that the monohydrate form of the drug is better tolerated than the hydrate.          

7.2.4 Proguanil
Dosage regimens: 3mg/kg daily
Adult dose: 2 tablets of 100mg daily
Duration of prophylaxis: start one day before departure and continue for
4 weeks after return
Use in special groups: pregnancy: safe
                                        breast feeding: safe
                                        children: safe
Main contra indications: liver or kidney dysfunction   
Comments: use only in combination with chloroquine. Proguanil may interfere with live typhoid vaccine  

WHERE DO I GO FOR MALARIA TEST
Certain regions have malaria endemicity and at the same time no available medical services. If you are staying in a malaria endemic area and probably isolated from medical care facility , its important to carry a rapid diagnostic test kit with you as part of the items to be incorporated in the first aid kit. This is a kit which is designed for domestic diagnosis of malaria. When you develop symptoms which you suspect to be malaria you could check with the RDT  for malaria before self medicating with anti malarial  tablets. This notwithstanding we advise that medical help be sought at the earliest opportunity.
If you are in Nairobi or any other major town or in a place with good medical facility it is prudent to seek prompt attention from a hospital or a health care center where the relevant tests can be done based on how your symptoms are.

WHERE DO I BUY MOSQUITO NETS AND WHICH ONES ARE GOOD
These are found in supermarkets and other major shopping centers. The permanet insecticide treated nets are the most suitable and best suited for protection against mosquito bites.

WHICH MOSQUITO REPELLANTS SHOULD I USE
Those labeled DEET are most suitable. Ensure that you apply on the entire exposed skin surface. This is best during the evenings when the mosquito are most likely to bite.