1. Malaria Chemoprophylaxis

2. Objective هدف
Identify basic facts, types, and the importance of malaria chemoprophylaxis.

3. Overview مرور
Chemoprophylaxis Types
Side Effects

4. Malaria Defined – Transmission
Mainly by certain species of female mosquitoes of the genus Anopheles
Transfusion
Needles
Congenitally
The Plasmodium genus of protozoal parasites (mainly P.falciparum, P.vivax, P.ovale, and P.malariae) have a life cycle which is split between a vertebrate host and an insect vector. The Plasmodium species, with the exception of P.malariae (which may affect the higher primates) are exclusively parasites of man. The mosquito is always the vector, and is always an Anopheline mosquito, although, out of the 380 species of Anopheline mosquito, only 60 can transmit malaria. Only female mosquitos are involved as the males do not feed on blood. The basic life cycle of the parasite is shown below:
The protozoa are transmitted to humans by female mosquitoes of the genus Anopheles. (Transmission can also occur by direct inoculation of infected red blood cells via transfusion, needles, or congenitally). Some signs and symptoms of the illness are high fever, chills, headache, anemia, and splenomegaly. Most serious and fatal
complications are caused by P. falciparum.

5. Malaria Defined Symptoms
Symptoms - fever and flu-like illness (chills, headache, muscle aches, and fatigue)
Symptoms may occur 7 to 9 days after being bitten by an infected mosquito
Malaria may cause anemia and jaundice

6. Malaria Defined Infectious Agent
Protozoa of the genus Plasmodium
P. falciparum - the most deadly
P. vivax - Middle East, Asia, Oceania, and Central and South America
P. malariae - less common
P. ovale - less common
Plasmodium falciparum infections, if not promptly treated, may cause kidney failure, coma, and death
Malaria is both an acute and chronic disease caused by protozoa of the genus Plasmodium. Four species cause human malaria: P. falciparum, P. vivax, P. malariae, and P. ovale. The protozoa are transmitted to humans by female mosquitoes of the genus Anopheles. (Transmission can also occur by direct inoculation of infected red blood cells via transfusion, needles, or congenitally). Some signs and symptoms of the illness are high fever, chills, headache, anemia, and splenomegaly. Most serious and fatal
complications are caused by P. falciparum.

7. Malaria Life Cycle
host and an insect vector. The Plasmodium species, with the exception of P.malariae (which may affect the higher primates) are exclusively parasites of man. The mosquito is always the vector, and is always an Anopheline mosquito, although, out of the 380 species of Anopheline mosquito, only 60 can transmit malaria. Only female mosquitos are involved as the males do not feed on blood. The basic life cycle of the parasite is shown below:

10. Malaria Chemoprophylaxis
Providers have the ultimate responsibility of prescribing medications for malaria
Choice of regimen is determined by two factors:
Drug resistance in specific locations.
Any allergic or other reaction to the anti-malarial drug of choice
Restriction by job
Regimen A. For areas where chloroquine resistant P. falciparum has NOT been reported, once weekly use of chloroquine alone is recommended. Chloroquine is usually well tolerated, and the few personnel who have side effects may tolerate the drug better by taking it with meals, or in divided twice-weekly doses.. Chloroquine
500 mg salt (300 mg base)/wk should begin 2 weeks before entering endemic areas of operation, taken once a week while deployed, and once a week for four weeks after leaving. The related drug, hydroxychloroquine, is useful as an alternative and may be better tolerated. It is available by open purchase under the trade name
Plaquenil R .
Regimen B. For areas where chloroquine resistant P. falciparum exists, mefloquine is recommended. Mefloquine is usually well tolerated at prophylactic dosage, but should not be taken by personnel with a history of seizures, severe psychiatric disorders, or those with cardiac conduction abnormalities. Aviators are prohibited
from using it. Mefloquine 250 mg/wk should begin 2 weeks before entering endemic areas of operation, taken once a week while deployed, and once a week for four weeks after leaving. If a two-week lead time prior to exposure is not possible, a loading dose of 250 mg/day on days 1, 2, 3, and 7 may be given. This is followed by the routine weekly regimen. This short interval loading dose period has been used with very few side effects. If this regimen is chosen, medical personnel should monitor unit members for side effects.
Regimen C. Doxycycline is also recommended for areas where chloroquine- resistant P. falciparum exists. If given under supervision, it is very effective. Doxycycline 100 mg/day is taken at approximately the same time of day, beginning 1-2 days before entering endemic areas of operation, taken daily while there, and daily for four weeks after leaving. It is the drug of choice for chemoprophylaxis in most parts of Southeast
Asia. One of the most common side effects of doxycycline is adverse gastrointestinal symptoms, usually nausea or vomiting. This often leads to compliance problems. These side effects may be avoided by taking doxycycline with a meal. Other side effects include photosensitivity manifested by a severe sunburn reaction, and an increased frequency of monilial vaginitis. The sunburn reaction can be prevented by avoiding prolonged exposure to sunshine, or sunscreen use. Females taking doxycycline should be supplied with nystatin suppositories to treat possible yeast infections when they occur.
Terminal Primaquine Prophylaxis: Currently, primaquine is theonly available drug for prevention of P. vivax and P. ovale relapse. As most endemic areas of the world have at least one of these species, terminal primaquine prophylaxis is recommended to eradicate hypnozoites. It can be initiated immediately or soon after personnel depart the area of exposure, or during the last two weeks using Regimens A, B, or C. This ensures an overlap of medication to eradicate parasites of any stage that may be present. No other medication eliminates Plasmodia merozoites in the liver. Without primaquine therapy, personnel can harbor dormant parasites in the
liver long after leaving the risk area. Terminal primaquine prophylaxis is given to ensure a complete cure.
Dosage is 15 mg base (26.3 mg salt)/day for 14 days; DOT recommended. Dosage may need to be increased to 30 mg if resistant P. vivax and P. ovale strains are present in the area. Personnel should be screened for G-6-PD deficiency before given primaquine. See Chapter 6 for details and recommendations. In certain instances, terminal primaquine prophylaxis may not be indicated. Consult with the cognizant Navy Environmental and
Preventive Medicine Unit or other authorities for recommendations on need for terminal primaquine prophylaxis or increased dosages.

11. Malaria Chemoprophylaxis
Mefloquine
(Lariam®)
250mg salt
(228 mg/base)
Once/week
Chloroquine Phosphate
(Aralen®)
500 mg salt
(300 mg base)
Doxycycline
100 mg
Once/day
Primaquine
(terminal prophylaxis for P. Vivax or P. ovale)
15 mg base
Once/day for 14 days
Regimen A. For areas where chloroquine resistant P. falciparum has NOT been reported, once weekly use of chloroquine alone is recommended. Chloroquine is usually well tolerated, and the few personnel who have side effects may tolerate the drug better by taking it with meals, or in divided twice-weekly doses.. Chloroquine
500 mg salt (300 mg base)/wk should begin 2 weeks before entering endemic areas of operation, taken once a week while deployed, and once a week for four weeks after leaving. The related drug, hydroxychloroquine, is useful as an alternative and may be better tolerated. It is available by open purchase under the trade name
Plaquenil R .
Regimen B. For areas where chloroquine resistant P. falciparum exists, mefloquine is recommended. Mefloquine is usually well tolerated at prophylactic dosage, but should not be taken by personnel with a history of seizures, severe psychiatric disorders, or those with cardiac conduction abnormalities. Aviators are prohibited
from using it. Mefloquine 250 mg/wk should begin 2 weeks before entering endemic areas of operation, taken once a week while deployed, and once a week for four weeks after leaving. If a two-week lead time prior to exposure is not possible, a loading dose of 250 mg/day on days 1, 2, 3, and 7 may be given. This is followed by the routine weekly regimen. This short interval loading dose period has been used with very few side effects. If this regimen is chosen, medical personnel should monitor unit members for side effects.
Regimen C. Doxycycline is also recommended for areas where chloroquine- resistant P. falciparum exists. If given under supervision, it is very effective. Doxycycline 100 mg/day is taken at approximately the same time of day, beginning 1-2 days before entering endemic areas of operation, taken daily while there, and daily for four weeks after leaving. It is the drug of choice for chemoprophylaxis in most parts of Southeast
Asia. One of the most common side effects of doxycycline is adverse gastrointestinal symptoms, usually nausea or vomiting. This often leads to compliance problems. These side effects may be avoided by taking doxycycline with a meal. Other side effects include photosensitivity manifested by a severe sunburn reaction, and an increased frequency of monilial vaginitis. The sunburn reaction can be prevented by avoiding prolonged exposure to sunshine, or sunscreen use. Females taking doxycycline should be supplied with nystatin suppositories to treat possible yeast infections when they occur.
Terminal Primaquine Prophylaxis: Currently, primaquine is theonly available drug for prevention of P. vivax and P. ovale relapse. As most endemic areas of the world have at least one of these species, terminal primaquine prophylaxis is recommended to eradicate hypnozoites. It can be initiated immediately or soon after personnel depart the area of exposure, or during the last two weeks using Regimens A, B, or C. This ensures an overlap of medication to eradicate parasites of any stage that may be present. No other medication eliminates Plasmodia merozoites in the liver. Without primaquine therapy, personnel can harbor dormant parasites in the
liver long after leaving the risk area. Terminal primaquine prophylaxis is given to ensure a complete cure.
Dosage is 15 mg base (26.3 mg salt)/day for 14 days; DOT recommended. Dosage may need to be increased to 30 mg if resistant P. vivax and P. ovale strains are present in the area. Personnel should be screened for G-6-PD deficiency before given primaquine. See Chapter 6 for details and recommendations. In certain instances, terminal primaquine prophylaxis may not be indicated. Consult with the cognizant Navy Environmental and
Preventive Medicine Unit or other authorities for recommendations on need for terminal primaquine prophylaxis or increased dosages.

12. Side Effects - Mefloquine
Serious adverse events
Seizures
Disorientation,
Toxic encephalopathy
Mefloquine is not authorized for prophylaxis in aviators and divers
Frequently observed side effects
Vomiting, (3% incidence).
Minor neurologic events.
Dizziness, vertigo, headache, decrease in sleep, visual, and auditory disturbances.
Neurologic side effects have an incidence of less than 1%.

13. Side Effects - Chloroquine
Frequently reported symptoms
Anorexia
Diarrhea
Abdominal cramps
Vomiting
Nausea
Mild symptoms reported
Headache
Deafness
Tinnitus
Blurred vision,
Long-term or high-dosage therapy may result in irreversible retinal damage.

14. Side Effects - Doxycycline
Common side effects
Nausea
epigastric distress
Vaginitis
Sensitivity to sun exposure
Less frequent
Diarrhea
Vomiting
Stomach and esophageal ulceration
The frequency and severity of gastrointestinal side effects may be reduced by taking doxycycline with meals
Absorption of this drug is impaired by antacids containing aluminum, calcium, magnesium, iron, or bismuth subsalicylate (Pepto)

15. Side Effects - Primaquine
The most frequently observed side effects
Abdominal discomfort
Nausea
Headache
Interference with visual accommodation
Do not use during pregnancy
Do not use with G-6-PD deficient individuals (physician determination)

16. Side Effects – Primaquine (G6PD)
Primaquine is the only currently available drug able to destroy dormant malarial pathogens in liver cells and prevent relapse of P.vivax or P.ovale malaria
Unfortunately, it is a strong oxidizing agent, and can cause severe hemolytic anemia in G-6-PD deficient personnel

17. What is G6PD deficiency? G-6-PD deficiency Symptoms
a hereditary, sex-linked enzyme defect that results in the breakdown of red blood cells when the person is exposed to the stress of infection or certain drugs
Symptoms
Fatigue
Pale color
Shortness of breath
Rapid heart rate
Yellow skin color (jaundice)
Dark urine
Enlarged spleen

18. G6PD deficiency Members who test G6PD deficient must
Be informed of the deficiency, the signs and symptoms they may experience and why they may occur, and the risks of taking oxidant medications.
Be advised to consult with their unit medic if malaria medications are administered to them
Refer these individuals to the flight surgeon for evaluation

19. Questions to ask the Patient
What exact city are you going to?
Certain risk is eliminated at higher elevations
What are the dates you’ll be in the country?
Risk may only be during certain seasons
What date are you leaving
If it’s less than a week , may need to consider starting with doxycycline then switching

20. Questions to ask the Patient (cont’d)
Are you allergic to any medication?
Patient may not be able to take this medication
Have you taken this medication before?
Are you taking any meds now?

21. Summary
Chemoprophylaxis Types
Side Effects

22. Questions?
سوالات
Questions?