Hindawi Publishing Corporation he Scientiic World Journal Volume 2013, Article ID 810380, 6 pages http://dx.doi.org/10.1155/2013/810380 Research Article Estimating the Optimal Control of Zoonotic Visceral Leishmaniasis by the Use of a Mathematical Model Laila Massad Ribas, 1 Vera Lucia Zaher, 1 Helio Junji Shimozako, 1 and Eduardo Massad 1,2 1 School of Medicine, University of S˜ ao Paulo and LIM 01-HCFMUSP, Avenida Dr. Arnaldo 455, 01246-903 S˜ ao Paulo, SP, Brazil 2 London School of Hygiene and Tropical Medicine, University of London, UK Correspondence should be addressed to Eduardo Massad; edmassad@usp.br Received 30 April 2013; Accepted 9 July 2013 Academic Editors: F. Henriquez, J. F. Lindo, and J. Lorenzo-Morales Copyright © 2013 Laila Massad Ribas et al. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. We argue that the strategy of culling infected dogs is not the most eicient way to control zoonotic visceral leishmaniasis (ZVL) and that, in the presence of alternative control strategies with better potential results, oicial programs of compulsory culling adopted by some countries are ineicient and unethical. We base our arguments on a mathematical model for the study of control strategies against ZVL, which allows the comparison of the eicacies of 5, alternative strategies. We demonstrate that the culling program, previously questioned on both theoretical and practical grounds is the less efective control strategy. In addition, we show that vector control and the use of insecticide-impregnated dog collars are, by far, more eicient at reducing the prevalence of ZVL in humans. 1. Introduction Zoonotic visceral leishmaniasis (ZVL) is one of the most important emerging parasite diseases [1]. It is endemic in rural areas of South America and is caused by Leishmania infantum (syn., L. chagasi). he parasite is transmitted by the phlebotomine sandly, Lutzomyia longipalpis, and the domestic dog is the main reservoir of the parasite in these areas [2, 3]. Once introduced into a community, the parasite is maintained in a dog-insect-dog peridomestic transmis- sion cycle [1], and occasionally infected lies bite people, causing ZVL. herefore, the prevalence and the incidence of canine ZVL are important epidemiological parameters for controlling transmission [4], and the estimation of which depends on the reliable identiication of infected dogs [5]. As a result, control programs for ZVL oten include elimination of infected dogs [6]. Control programs also include detection and treatment of human cases and vector control [7]. More recently, however, two additional control programs have been suggested as alternative or complementarily related to the classical approach, namely, insecticide-impregnated dog collars [8] and a transmission-blocking vaccine [9]. In the Mediterranean, where dogs are considered “valu- able” [10], ZVL is both a medical and a veterinary problem. In Brazil, the country were 90% of New World’s ZVL cases are reported, human cases are numerous and where human cases are many and dogs are considered “less valuable” [10], ZVL is chiely considered to be only a medical problem. As a result, 850,000 dogs are screened annually in Brazil, and between 20,000 [11] and 25,000 [10] dogs are culled upon positive diagnosis. his perspective of undervaluing dogs is the oicial position of some governments like the Brazilian Health Authorities, which forbid the treatment of infected dogs with drugs of human use (Interministerial law no. 1,426 of July 11 2008, Editorial of Clinica Veterin´ aria 83: 16-17, 2009) and impose the elimination of seropositive dogs as compulsory. Health agents threaten dog owners with heavy ines for refusing the serological analysis of their animals, and thousands of diagnosed dogs, with a high probability of being false positives, are eliminated every year without a counterproof. Hence, instead of submitting their dogs to the serological screening, owners refuse the entrance of health agents into their homes or transfer their animals to areas where there is no serological screening. Some owners even