Chapter 3Infectious Diseases Related To Travel
LeAnne M. Fox
Lymphatic filariasis is caused by the filarial nematodes Wuchereria bancrofti, Brugia malayi, and B. timori.
MODE OF TRANSMISSION
Vectorborne transmission occurs through the bite of infected Aedes, Culex, Anopheles, and Mansonia mosquito species.
Lymphatic filariasis affects an estimated 120 million people in tropical areas of the world. Lymphatic filariasis is found in sub-Saharan Africa, Egypt, southern Asia, the western Pacific Islands, the northeastern coast of Brazil, Guyana, Haiti, and the Dominican Republic. Since most infections are asymptomatic, many go unrecognized. Short-term travelers to endemic areas are at low risk for this infection. Travelers who visit endemic areas for extended periods of time (generally >3 months) and who are intensively exposed to infected mosquitoes are at higher risk of infection. Most infections seen in the United States are in immigrants from endemic countries.
A recent report from the GeoSentinel Surveillance Network showed only 0.62% (271 of 43,722) of medical conditions reported from 1995 through 2004 were caused by any filarial infection, and of these, only 68 (25%) were caused by W. bancrofti and were acquired worldwide: 32% from South America, 12% from sub-Saharan Africa, 22% from south-central Asia, and 14% from the Caribbean. As expected, most cases (62%) were seen in immigrants or refugees. In the few nonresident visitors with a known trip duration who acquired W. bancrofti, the stay was >180 days.
Most infections are asymptomatic, but living adult worms cause progressive lymphatic vessel dilation and dysfunction. Lymphatic dysfunction may lead to lymphedema of the leg, scrotum, penis, arm, or breast, which can increase in severity as a result of recurrent secondary bacterial infections. Tropical pulmonary eosinophilia is a potentially serious progressive lung disease that presents with nocturnal cough, wheezing, and fever, resulting from immune hyperresponsiveness to microfilariae in the pulmonary capillaries.
The standard for diagnosis is microscopic detection of microfilariae on a thick blood film. In most endemic areas, the highest concentration of microfilariae in the peripheral blood occurs at night; therefore, blood specimens should be collected between 10 pm and 2 am. Determination of serum antifilarial IgG is also a diagnostically useful test. This assay is available through the Parasitic Diseases Laboratory at the National Institutes of Health or through CDC’s Division of Parasitic Diseases and Malaria.
Diethylcarbamazine (DEC) is the drug of choice to treat travelers with W. bancrofti, B. malayi, or B. timori infection. DEC, which is available to physicians licensed in the United States for this purpose, can be obtained from the CDC Parasitic Disease Drug Service under an investigational new drug protocol (404-639-3670; www.cdc.gov/laboratory/drugservice/index.html). DEC kills circulating microfilariae and is partially effective against the adult worms. DEC is also used to treat tropical pulmonary eosinophilia.
Although ivermectin kills microfilariae, it does not kill the adult worms. Many patients with lymphedema are no longer infected with the filarial parasite and do not benefit from antifilarial drug treatment. For chronic manifestations of lymphatic filariasis, such as lymphedema and hydrocele, specific lymphedema treatment—including hygiene, skin care, physiotherapy, and in some cases, antibiotics—and surgical repair are recommended. To ensure correct diagnosis and treatment, travelers should consult an infectious disease or tropical medicine specialist.
PREVENTIVE MEASURES FOR TRAVELERS
No vaccine is available. No drugs for preventing infection are available. Protective measures include avoidance of mosquito bites through the use of personal protection measures against biting insects (see Chapter 2, Protection against Mosquitoes, Ticks and Other Insects and Arthropods).
- Abramowicz M. Drugs for Parasitic Infections. New Rochelle (NY): The Medical Letter, Inc; 2007.
- Dreyer G, Addiss D, Dreyer P, Noroes J. Basic lymphoedema management: treatment and prevention of problems associated with lymphatic filariasis. Hollis (NH): Hollis Publishing Co; 2002.
- Dreyer G, Addiss D, Noroes J, Amaral F, Rocha A, Coutinho A. Ultrasonographic assessment of the adulticidal efficacy of repeat high-dose ivermectin in bancroftian filariasis. Trop Med Int Health. 1996 Aug;1(4):427–32.
- Dreyer G, Addiss D, Roberts J, Noroes J. Progression of lymphatic vessel dilatation in the presence of living adult Wuchereria bancrofti. Trans R Soc Trop Med Hyg. 2002 Mar–Apr;96(2):157–61.
- Dreyer G, Medeiros Z, Netto MJ, Leal NC, de Castro LG, Piessens WF. Acute attacks in the extremities of persons living in an area endemic for bancroftian filariasis: differentiation of two syndromes. Trans R Soc Trop Med Hyg. 1999 Jul–Aug;93(4):413–7.
- Eberhard ML, Lammie PJ. Laboratory diagnosis of filariasis. Clin Lab Med. 1991 Dec;11(4):977–1010.
- Gardner A, Hardy L, Bell SK. Eosinophilia in a returned traveler. Clin Infect Dis. 2010 Mar 1;50(5):745–6; 92–4.
- Lipner EM, Law MA, Barnett E, Keystone JS, von Sonnenburg F, Loutan L, et al. Filariasis in travelers presenting to the GeoSentinel Surveillance Network. PLoS Negl Trop Dis. 2007;1(3):e88.
- Michael E, Bundy DA, Grenfell BT. Re-assessing the global prevalence and distribution of lymphatic filariasis. Parasitology. 1996 Apr;112 ( Pt 4):409–28.
- Nutman TB, editor. Lymphatic Filariasis. London: Imperial College Press; 2000.
- Ottesen EA. Efficacy of diethylcarbamazine in eradicating infection with lymphatic-dwelling filariae in humans. Rev Infect Dis. 1985 May–Jun;7(3):341–56.
- Shenoy RK, Suma TK, Rajan K, Kumaraswami V. Prevention of acute adenolymphangitis in brugian filariasis: comparison of the efficacy of ivermectin and diethylcarbamazine, each combined with local treatment of the affected limb. Ann Trop Med Parasitol. 1998 Jul;92(5):587–94.
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