Control of tungiasis through intermittent application of a plant-based repellent: an intervention study in a resource-poor community in Brazil.

Abstract

BACKGROUND:

Tungiasis, an ectoparasitosis caused by the female sand flea Tunga penetrans, is an important health problem in many impoverished communities in the tropics. Sand flea disease is associated with a broad spectrum of clinical pathology and severe sequels are frequent. Treatment options are limited.

METHODOLOGY/PRINCIPAL FINDINGS:

We assessed the effectiveness of the intermittent application of the plant-based repellent Zanzarin to reduce infestation intensity and tungiasis-associated morbidity in a resource-poor community in Brazil, characterized by a very high attack rate. The study population was randomized into three cohorts. Initially, during a period of four weeks, the repellent was applied twice daily to the feet of all cohort members. This reduced the number of embedded sandfleas to 0 in 98% of the participants. Thereafter members of cohort A applied the repellent every second week twice daily for one week, members of cohort B every fourth week for one week, and members of cohort C served as controls. Infestation intensity and tungiasis-associated morbidity were monitored during five months. The intermittent application of Zanzarin for one week every second week significantly reduced infestation intensity from a median 4 lesions (IQR 1-9) during the whole transmission season. In contrast, in cohort B (application of the repellent every fourth week) the infestation intensity remained twice as high (median 8 lesions, IQR 9-16; p = 0.0035), and in the control cohort C 3.5 times as high (median 14 lesions; IQR 7-26; p = 0.004 during the transmission season). Tungiasis-related acute pathology remained very low in cohort A (median severity score 2; IQR 1-4) as compared to cohort B (median severity score 5; IQR 3-7; p<0.001), and control cohort C (median severity score 6.5; IQR 4-8; p<0.001).

CONCLUSIONS/SIGNIFICANCE:

Our study shows that in a setting with intense transmission, tungiasis-associated morbidity can be minimized through the intermittent application of a plant-based repellent.

• Authors: John Buckendahl, Jörg Heukelbach, Liana Ariza, Judith Dorothea Kehr, Martin Seidenschwang, Hermann Feldmeier
• Journal: PLoS neglected tropical diseases (PLoS Negl Trop Dis) Vol. 4 Issue 11 Pg. e879 (Nov 09 2010) ISSN: 1935-2735 [Electronic] United States
• PMID: 21085467 (Publication Type: Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)

Chemical References

• Insect Repellents
• Plant Oils
• Plant Preparations

Topics

• Adolescent
• Adult
• Aloe (chemistry)
• Animals
• Brazil (epidemiology)
• Child
• Child, Preschool
• Cocos (chemistry)
• Cohort Studies
• Communicable Disease Control
• Ectoparasitic Infestations (epidemiology)
• Female
• Humans
• Infant
• Insect Repellents (administration & dosage)
• Male
• Middle Aged
• Plant Oils (administration & dosage)
• Plant Preparations (administration & dosage)
• Poverty
• Tunga (drug effects)
• Tungiasis (drug therapy, economics, parasitology, prevention & control)
• Young Adult