Instructions for use Title Clinical Cutaneous Leishmaniasis Rates Are Associated with Household Lutzomyia gomezi

American cutaneous leishmaniasis (ACL) transmission patterns have been increasingly associated with domestic and peridomestic environments. Here, we present results from an epidemiological survey of 94 people from 24 households in Trinidad de Las Minas, western Panama. We studied the role of sand fly abundance, housing quality, peridomicile landscape matrix, and vegetation structure on shaping household clinical ACL rate patterns at Trinidad de Las Minas. We found that sand fly abundance was significantly associated with household clinical ACL rates, with a 6% rate increase for each additional Lutzomyia gomezi sand fly found inside a domicile. American cutaneous leishmaniasis (ACL) is an increasing public health concern in the New World. Disease burden is primarily concentrated in the most socially excluded populations of Panama, a pattern common in Central America. In Panama ACL control is focused on the clinical treatment of human patients with skin lesions, without considering active surveillance and sand fly control. Nevertheless, the increased evidence for domicilary and peridomiciliary transmission calls for improving current vector control strategies. Here, we present results from a baseline epidemiological survey, conducted before a sand fly control insecticide thermal fogging intervention. We surveyed 24 households (with 94 residents in total) at Trinidad de Las Minas (8 °46¢322N; 79 °59¢452W), western Panama province. Climate has a dry (December toMarch) and a rainy (April to November) season, the mean temperature is 26°C year-round and rainfall can vary between 28 and 570 mm per month. The survey was conducted during May 2010 in 24 houses (out of 128 houses in the village). Households were selected based on sand fly presence and presence of wild animal reservoirs (both confirmed by residents). The number of selected houses was limited by existing resources for the study, especially the availability of light traps (we only had 48 traps). On average (±SE) households had 3.91 ± 0.09 individuals. Clinical ACL was considered when the next conditions were met: 1) closed lesions: presence of characteristic ACL scars assessed by experienced clinicians and parasitologists of the research team, and self-reported parasitologic positive diagnosis at a health center (confirmed by the attendance record to the local government health facility); 2) active lesions were parasitologically diagnosed at the Parasitology Department and Clinical Tropical Medicine unit of the Gorgas Institute in Panama and were clinically treated at the local government health facility. From April to June 2010, sand flies were collected monthly using modified HP light-traps with an additional LED light. Monthly sand fly collections included one trap placed 2 mt above the ground for one night in the main bedroom of every household (domicile) and a second trap was placed at the same height, above vegetation, within 50 m of the house (i.e., peridomicile). Traps were set to sample sand flies from 6:00 PM to 6:00 AM. We also collected data on different aspects of the housing quality (materials, floor, electricity, ceiling and whether walls and doors had gaps or holes that allowed the entrance of insects), the peridomiciliary landscape matrix (presence of rubbish, water bodies, wood logs, cultivation of vegetables, kind of tree: palms, fruits, or ornamental) and vegetation structure (percentage of: canopy cover, canopy height, vegetation ground cover, bush cover, and shade, all measured following standard ecological protocols) for each household. This study was approved by the National Review Board, Comité Nacional de Bioética de la Investigación, Instituto Conmemorativo Gorgas de Estudios de la Salud, Panamá City, Panamá (561 /CNBI/ICGES/06). In the 94 people surveyed we found a total of 32 closed lesions and 6 active lesions. Combining closed and active lesions each household had an average (±SE) of 1.58 ± 0.09 ACL cases. The most common sites of lesions were the legs and arms (58%), followed by lesions in the face (29%). Single lesions were observed in 75% of cases (range 1–3), and no apparent mucosal involvement was observed in this sample. Most of the active lesions were in children £ 12 years of age (5 of 6; 83%). To assess the role of sand fly abundance, housing quality, peridomicile landscape matrix, and vegetation structure on clinical ACL rates at surveyed households, we used Poisson rate generalized linear models (PRGLM). The PRGLMs have the advantage of accounting for household size (i.e., number of individuals living in a household) and residuals can be further inspected for unaccounted spatial autocorrelation. Given that we had 24 observations (households), i.e., at most 23 parameters could be estimated, we reduced the number of predictors by estimating the first principal component (pc) of a variance–covariance matrix, respectively, for the group of variables related to housing quality (DI), peridomicile landscape matrix (PI) and vegetation structure (EI). In all three sets of variables the first pc accounted for slightly over 40% of the variability, and in all cases the first pc could be interpreted as weighted averages *Address correspondence to Jose E. Calzada, Departamento de Parasitologı́a, InstitutoConmemorativoGorgas deEstudios de la Salud, Apartado Postal No. 0816-02593, Panama City, Republic of Panama. E-mail: jcalzada@gorgas.gob. pa