Insects, Malaria, and Children

Abstract & Commentary

Synopsis: Families traveling with infants and children should be aggressive about malaria prevention using DEET, permethrin, and chemoprophylaxis. Both this review and that of associate editor, Lin Chen, MD, in this issue underscore the importance of bednets and repellents as critical components of malaria prophylaxis

Source: Stauffer WM, et al. Traveling with infants and children. Part IV: Insect avoidance and malaria prevention. J Travel Med. 2003;10:225-240.

Traveling children are at risk for insect bites and insect-born diseases. Children should be dressed with clothes covering arms and legs and should avoid the use of products with flowery scents. Spending dusk to dawn indoors behind screened windows or in air-conditioned areas decreases the risk of insect bites. Mosquito netting impregnated with permethrin or deltamethrine should be used. DEET (N,N-diethyl-meta-toluamide) is the safest, most thoroughly studied, and most effective chemical repellent currently available and should be applied to exposed skin, while avoiding potential contactwith the eyes or mouth. Age and weight, as well as itinerary, figure into the choice of a chemoprophylactic agent.

Comment by Philip R. Fischer, MD, DTM&H

Preparation for international travel with infants and children can be stressful. What is a family to do? What is a travel medicine practitioner to do? Once again, Stauffer and colleagues have provided practically relevant, academically sound guidance to facilitate safe and healthy travel for infants, children, and adolescents. Previous review articles dealt with general anticipatory guidance,1 immunizations,2 and travelers’ diarrhea.3 Now, the last segment of this helpful series is a well-documented (125 references) overview of insect avoidance and malaria prevention.

Personal Protection Barriers

Personal protective measures are appropriate for all travelers to malarial areas and are the primary prevention strategy for infants. Without independent mobility during the first several months of life, babies are directly dependent on the microenvironment established by their parents and adult traveling companions. Insect-free areas can be provided through the use of physical barriers. Permethrin-impregnated netting can be spread over car seats, cribs, playpens, strollers, and even backpacks. Self-supporting netted "tents" are easily portable for use in a variety of settings.

Older children and adolescents can also choose to avoid outdoor activities between dusk and dawn. They can participate in the selection of comfortable clothing that covers most of their skin. The use of bed nets, screened windows, or air conditioning should be encouraged during sleeping times for travelers of all ages.

Chemical Barriers

A variety of chemical agents are used for children, but efficacy varies. While other agents might be considered in settings where mosquito bites are merely a nuisance, Stauffer’s group suggests that DEET is the only repellent currently available that should be recommended for use with infants and children in malarious areas. A 30-35% solution is preferred. DEET is safe when used appropriately. Apply first to hands of caregivers and then to the child; avoid application to eyes or parts of hands that might come into contact with eyes or mouths; use only on intact exposed skin, and rinse off when returning to a protected environment. Adverse events have been very rarely reported in children using DEET, but there is no evidence that the risk for adverse events of correctly used DEET is linked to age.

Picaridin (LBR3023, Bayrepel) is available in some countries for use in children older than 2 years of age but does not seem to have any distinct advantage over DEET.

Other "repellents," such as those containing citronella, provide only modest protection for short periods of time. Toxicity has rarely been reported with citronella. Permethrin is a safe and effective contact insecticide. It can be applied to clothes and bednets and may be air-dried and then used 4 or more hours after the application. Permethrin is safe for use on clothes and nets of children of all ages.

Chemoprophylaxis

The itinerary-based indications for malaria chemoprophylaxis are the same for children as for adults. Age-specific and weight-based dosing considerations, however, are important. For instance, doxycycline is not advised for children younger than 8 years of age, and the combination of atovaquone and proguanil is not officially recommended for children weighing less than 11 kg.

Chloroquine is still appropriate chemoprophylaxis in a few areas of the world. It is given in a weekly oral dose of 5 mg base per kg body weight (maximum of 300 mg base per weekly dose) beginning 1 week prior to travel and continuing until the child has been out of the malaria area for 4 weeks. The bitter-tasting tablets can be crushed and mixed with a palatable food for use in children. A liquid formulation is available in Europe and some other parts of the world.

Mefloquine is similarly used in a bitter-tasting 5 mg/kg weekly oral dose (maximum, 250 mg) beginning 1-2 weeks before travel and continuing until 4 weeks after leaving the malaria area. As with chloroquine, compounding pharmacies can help prepare exact doses for infants, and older children may approximate the dose upward to the nearest quarter pill. Side effects seem to be less common and less bothersome in children than in adults, but specific data are lacking. As for adults, children are not advised to use prophylactic mefloquine if they have an active seizure disorder, psychiatric illness, or cardiac conduction abnormalities. Mefloquine would not be contraindicated in children with a remote (but not recent) history of febrile seizures and in children with isolated attention deficit disorders.

Atovaquone-proguanil provides effective malarial prophylaxis in children. It is given daily, beginning 1-2 days prior to arrival in a malarial area and continuing for 7 days after leaving the malarial area in a weight-adjusted dose ("pediatric pills" contain 62.5 mg atovaquone and 25 mg proguanil; 1 pill daily if 11-20 kg, 2 if 21-30 kg, 3 if 31-40 kg, 4 or an equivalent single "adult pill" if more than 40 kg). It is less bitter than chloroquine and mefloquine but is not available in a liquid form. Emerging data suggest safety and efficacy in small infants, but it is not yet routinely advised for children weighing less than 11 kg. Doxycycline can cause cosmetically important dental staining if used in children younger than 8 years of age. Otherwise, it is used as for adults with a 2 mg/kg daily dose up to the adult 100-mg dose limit.

The use of "standby treatment" when symptoms of malaria begin is controversial in children. Ideally, a febrile child who has been exposed to malaria should be immediately provided with good medical care. If that is not possible, atovaquone-proguanil could be a preferred agent for presumptive treatment while en route to medical care.

Lactating mothers on prophylaxis do pass some medicine on to nursing children. The amount of medication, however, is not felt to be harmful to the child. Conversely, the amount transferred does not confer adequate protection to the child. Infants should receive standard chemoprophylaxis dosing, whether they are nursing or not.

Indeed, giving pretravel advice to families traveling with children can be a daunting task. Stauffer et al have helpfully contributed another useful review to the literature. This gives travel medicine practitioners specific, directed guidance in helping traveling families prevent insect bites and malaria in children. Implementing this information should help increase family comfort and decrease pediatric morbidity.

Dr. Fischer is Professor of Pediatrics, Department of Pediatric & Adolescent Medicine, Mayo Clinic, Rochester, MN. 

References

1. Stauffer WM, et al. Traveling with infants and young children. Part I: Anticipatory guidance: Travel preparation and preventive health advice. J Travel Med. 2001;8:254-259.

2. Stauffer WM, Kamat D. Traveling with infants and children. Part 2: immunizations. J Travel Med. 2002;9:82-90.

3. Stauffer WM, et al. Traveling with infants and young children. Part III: travelers’ diarrhea. J Travel Med. 2002;9:141-150.