Dogs as reservoirs for Leishmania braziliensis.
Article Type: Letter to the editor
Subject: Leishmania (Health aspects)
Dogs (Diseases)
Dogs (Research)
Author: Dantas-Torres, Filipe
Pub Date: 02/01/2011
Publication: Name: Emerging Infectious Diseases Publisher: U.S. National Center for Infectious Diseases Audience: Academic; Professional Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2011 U.S. National Center for Infectious Diseases ISSN: 1080-6040
Issue: Date: Feb, 2011 Source Volume: 17 Source Issue: 2
Topic: Event Code: 310 Science & research
Geographic: Geographic Scope: Brazil Geographic Name: Ceara, Brazil; Ceara, Brazil Geographic Code: 3BRAZ Brazil
Accession Number: 251376970
Full Text: To the Editor: I have read the review by Sousa and Pearson (1), which provides a fascinating historical account of the Great Drought and the smallpox epidemic of the 1870s and their association with the emergence of cutaneous leishmaniasis in Ceara, Brazil. In their review, the authors went back to the 19th century, remembering the hard years experienced by those who faced the Great Drought, which prompted the immigration of thousands of persons from Ceara to the Amazon region, and a devastating smallpox epidemic, which resulted in the death of >100,000 persons. Later, they returned to the present situation of cutaneous leishmaniasis in Brazil.

I would like to address the role of dogs as reservoirs of Leishmania (Viannia) braziliensis. Sousa and Pearson stated that "no animal reservoir other than dogs has been identified in Ceara" and that "a sylvatic reservoir has not been identified for L. (V) braziliensis in Ceara and other areas," concluding that "dogs appear to be the most important reservoir in domestic and peridomestic transmission."

Conversely, recent studies have indicated that rodents and other small mammals are the primary reservoirs for L. (V) braziliensis (2) and that, so far, no strong evidence indicates that dogs could act as reservoirs for this parasite (3,4). The finding of dogs infected by L. (V.) braziliensis in leishmaniasis-endemic areas is expected because they are susceptible to this parasite and are often exposed to phlebotomine sandflies. However, this finding does not imply that dogs are important reservoirs. Indeed, they represent a poor source of L. (V.) braziliensis (3). For these reasons, dogs cannot be incriminated as the most important reservoirs in the domestic and peridomestic transmission cycles of L. (V.) braziliensis.

Filipe Dantas-Torres

Author affilion: Universita degli Studi di Bari, Bari, Italy

DOI: 10.3201/eid1702.091823

References

(1.) Sousa AQ, Pearson R. Drought, smallpox, and emergence of Leishmania braziliensis in northeastern Brazil. Emerg Infect Dis. 2009;15:916-21. DOI: 10.3201/ eid1506.071331

(2.) Brandao-Filho SP, Brito ME, Carvalho FG, Ishikawa EA, Cupolillo E, FloeterWinter L, et al. Wild and synanthropic hosts of Leishmania (Viannia) brazil iensis in the endemic cutaneous leishmaniasis locality of Amaraji, Pernambuco State, Brazil. Trans R Soc Trop Med Hyg.2003:97:291-6.

(3.) Dantas-Torres F. The role of dogs as reservoirs of Leishmania parasites, with emphasis on Leishmania (Leishmania) infantum and Leishmania (Viannia) bra ziliensis. Vet Parasitol. 2007;149:139-46. DOI: 10.1016/j.vetpar.2007.07.007

(4.) Reithinger R, Davies CR. Is the domestic dog (Canis familiaris) a reservoir host of American cutaneous leishmaniasis? A critical review of the current evidence. Am J Trop Med Hyg. 1999;61:530-41.

Address for correspondence: Filipe Dantas-Torres, Dipartimento di Sanita Pubblica e Zootecnia, Facolta di Medicina Veterinaria, Universita degli Studi di Bari, Strada Provinciale per Casamassima km 3, 70010 Valenzano, Bari, Italy; email: f.dantastorres@veterinaria.uniba.it

In Response: We agree with most points raised by Dantas-Torres (1). However, so far our statement related to the reservoir(s) of Leishmania (Viannia) braziliensis (2) is correct for Ceara. Oliviera-Lima (3) conducted a case-control study that definitively incriminated dogs as a reservoir host of L. (V) braziliensis in Baturite, Ceara. He showed that infected dogs in households increased the risk for infection with L. (V.) braziliensis by 3.2-fold among resident children. The risk increased to 6-fold when infected dogs had leishmaniasis-like skin lesions. Additionally, his observations suggested that animals other than dogs might be involved. In another study, Santana (4) examined 272 small mammals (213 rodents and 59 marsupials) in the same area; tissue culture and hamster inoculation showed none to be infected with L. (V) braziliensis, although some cultures were contaminated by fungi and bacteria. On the basis of these findings, a sylvatic reservoir for L. (V) braziliensis has not been identified in Baturite, Ceara. However, Brandao-Filho et al. found that rodents in Pernambuco State, Brazil, were infected with L. (V.) braziliensis and stated that they were the primary reservoir (5). We concur with Lainson and Shaw (6) and conclude that information about mammalian reservoirs of L. (V.) braziliensis is incomplete.

Anastacio de Queiroz Sousa and Richard D. Pearson

Author affiliations: Federal University of Ceara School of Medicine, Fortaleza, Brazil (A.Q. Sousa); and University of Virginia School of Medicine, Charlottesville, Virginia, USA (R.D. Pearson)

DOI: 10.3201/eid1702.101669

References

(1.) Dantas-Torres F. Dogs as reservoirs for Leishmania braziliensis [letter]. Emerg Infect Dis. 2011;17:324-5.

(2.) Sousa AQ, Pearson R. Drought, smallpox, and emergence of Leishmania braziliensis in northeastern Brazil. Emerg Infect Dis. 2009;15:916-21. DOI: 10.3201/ eid1506.071331

(3.) Oliveira-Lima JW. Domestic transmission of cutaneous leishmaniasis in Brazil [dissertation]. Cambridge (MA): Harvard University; 1995.

(4.) Santana EW. The role of small mammals as reservoir hosts of cutaneous leishmaniasis in the "serra de Baturite," an endemic zone in Ceara State, Brazil [dissertation]. Bristol (UK): University of Bristol; 1999.

(5.) Brandao-Filho SP, Brito ME, Carvalho FG, Ishikawa EA, Cupolillo E, Floeter-Winter L, et al. Wild and synanthropic hosts of Leishmania (Viannia) braziliensis in the endemic cutaneous leishmaniasis locality of Amaraji, Pernambuco State, Brazil. Trans R Soc Trop Med Hyg. 2003;97:291-6. DOI: 10.1016/S0035 9203(03)90146-5

(6.) Lainson R, Shaw JJ. Evolution, classification and geographical distribution. In: Peters W, Killick-Kendrick R, editors. The leishmaniases in biology and medicine. Vol. 1. London: Academic Press; 1987. p. 1-120.

Address for correspondence: Anastacio de Queiroz Sousa, Departamento de Medicina Clinica, Federal University of Ceara School of Medicine, Rua Professor Costa Mendes, 1608-4[degrees] Andar, Rodolfo Teofilo, CEP 60430140, Fortaleza, Ceara, Brazil; email: aqsousa@ gmail.com
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