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Another world in Africa
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This month’s Pharmacology Consult will depart somewhat from the monthly norm to describe the experiences and information gathered from the column author and a team of clinicians when they recently traveled to Tanzania on a medical mission. Observed diseases and daily life activities allowed our medical mission team to, in many respects, experience another world in Africa.
Thirty-five clinicians — including several pediatricians, surgeons, nurses, pharmacists and care providers for optometry, dental and water treatment from the Midwest and Florida — comprised the pediatric medical team to Singida Regional Hospital and clinics in the Singida Region of central Tanzania in early April. An additional medical team providing care to adults followed the pediatric team. This medical mission was organized through Outreach International, a nonprofit organization with the goal of providing safe water, food, medical care and education to children in need in developing countries. Care provided from the team included medical personnel time in addition to donated pharmaceuticals, surgical equipment and formal teaching and lecture opportunities. Approximately 700 children were seen during one week by the pediatric team.
Malaria
Although many illnesses and diseases commonly seen in children in the United States, such as acute otitis media and asthma, were also seen in Tanzanian children, other diseases more unique to countries outside the United States were also seen.
Even though we saw no children with active malaria, the potential to acquire this common infectious disease was pervasively experienced. All team members slept with mosquito netting or tents and were taking oral prophylactic anti-malarial medications. The CDC lists Malaria Information and Prophylaxis by Country on its website, providing useful information on drug resistance and recommended chemoprophylaxis for Tanzania and other countries. Chloroquine resistance is listed for Tanzania, and atovaquone/proguanil (Malarone, GlaxoSmithKline), doxycyline, mefloquine or primaquine are recommended chemoprophylactic options.
How common is malaria? As one might imagine, malaria does not commonly occur in the United States — about 1,500 cases are diagnosed annually. Most of these cases are diagnosed in immigrants or travelers returning from countries where malaria is more common. Globally, however, 190 million to 311 million individuals had malaria in 2008, and 708,000 to 1 million deaths occurred. Most of these deaths were in children. Malaria is the fifth leading cause of death from infectious disease worldwide and the second leading cause of death from infectious disease in Africa (HIV/AIDS is the leading cause). Approximately 50% of the world’s population is at risk for malaria. Ninety percent of deaths from malaria occur in African countries located south of the Sahara desert. Malaria results from infection with one of the parasitic Plasmodium species (most commonly P. falciparum in Africa). If diagnosed early, malaria is generally treatable and curable.
Malaria has been described historically for more than 4,000 years, as descriptions of what may have been malaria have been found in ancient Chinese and Greek writings. More recently noted is evidence published this year that King Tutankhamun, ruler of Egypt from 1333 B.C. to 1324 B.C. during the 18th dynasty, had malaria. Researchers of several Egyptian mummies found DNA evidence suggestive of infection with P. falciparum, a parasitic species known to cause malaria. Researchers speculate that King Tutankhamun succumbed to multiple inflammatory, immune-suppressive disorders, avascular bone necrosis and fracture — as well as malaria.
In addition to oral chemoprophylaxis, our team members also frequently applied insect repellent, as certain types of mosquitoes that feed on humans commonly transmit malaria in many African countries. Although applying insect repellent to prevent malaria is not likely a goal in the United States, insect repellents are more likely to be used with the summer and outdoor season approaching and thus worthy of brief discussion. Parenthetically, acquiring malaria locally from a mosquito bite is not impossible in the United States (although highly unlikely). During the past 50 or more years in the United States, 63 outbreaks of locally transmitted malaria from mosquito bites have occurred.
How? Local mosquitoes bite individuals who have malarial parasites, which were acquired in endemic areas, and then these mosquitoes bite local individuals and transmit the malaria parasites. Several insect repellent agents are available in numerous products and dosage forms. Many factors affect insect repellent efficacy, including species of the biting insect; environmental conditions (temperature, humidity, altitude, wind speed); and individual characteristics (age, sex, level of activity). The intended goal of using insect repellent is also important (that is, preventing nuisance insect bites or preventing malaria in endemic areas). N,N-diethyl-3-methylbenzamide (DEET) is generally regarded as the most effective topically applied insect repellent. The CDC states that DEET is the most effective agent available, and published data from clinical studies support this. Insect repellent products containing picardin are also likely to be effective. Researchers of a controlled study evaluated several insect repellent agents on human volunteers and found products containing DEET to be the most protective and to have the longest duration of protection. In a 23.8% concentration, DEET provided five hours of protection as compared with 1.5 hours of protection from 4.75% DEET. Thus, products containing higher concentrations of DEET provide a longer duration of effect. Some products containing 98% DEET are available, and they may provide up to 10 hours of protection, although duration of effect can be diminished by activity, perspiration, wind and other factors. However, some data indicate that duration of effect does not increase significantly at DEET concentrations >50%. Products containing DEET in concentrations >50% may be appropriate where the risk for malaria or other serious diseases transmitted by insect bite is great. The AAP recommends if products containing DEET are used on children, the concentration should be limited to 30% (stating higher concentrations do not offer greater protection). The AAP also does not recommend the use of insect repellents on infants aged younger than 2 months.
Another medical world
One of our team physicians suspected a child had leprosy, although the diagnosis was not certain. Also known as Hansen’s disease, leprosy affects skin, peripheral nerves and mucous membranes and results from infection with Mycobacterium leprae. The CDC reports that this bacterium has never been successfully grown in bacteriologic media, although it has been grown in mouse foot pads. Worldwide, more than 1 million individuals are permanently disabled because of leprosy. Leprosy is curable if diagnosed early and treated appropriately. Countries where leprosy is more commonly found include Brazil, Madagascar, Mozambique, Nepal and Tanzania. The 2009 Red Book states that 101 new cases were reported in the United States, primarily in foreign-born individuals. Interestingly, certain individuals may be genetically at increased risk for contracting leprosy. An individual living with a spouse who has leprosy may be less likely to contract the disease than the biological children of the person.
As pediatric clinicians are well aware, treating group A streptococcal upper respiratory tract disease with antibiotics reduces nonsuppurative sequelae, such as acute rheumatic fever. The incidence of acute rheumatic fever has decreased significantly in the United States, although focal outbreaks can still occur. According to WHO, more than 2.4 million children (aged 5 to 14 years) globally have rheumatic heart disease. The majority, 79%, of these cases occur in less developed countries. Carditis is a “major” criterion of the Jones Criteria for Diagnosis of First Attack of Acute Rheumatic Fever. Valvulitis is a universal finding of rheumatic carditis and manifests as cardiac murmurs. Our team saw many children in the clinic with cardiac murmurs likely due to rheumatic heart disease.
Tanzania is a beautiful country — including its children, geography and wildlife. It is unfortunate that many of the children in Tanzania and other African countries acquire or succumb from infectious diseases relatively unknown to us in the United States. Increased awareness of global pediatric health issues is worthy of our attention.
Edward A. Bell, PharmD, is a Professor of Clinical Sciences at Drake University College of Pharmacy, Blank Children’s Hospital and Clinics in Des Moines, Iowa.
For more information:
- Fradin MS. N Engl J Med. 2002;347:13-18.
- Hawass Z. JAMA. 2010;303:638-647.