Filariasis Caused by Dirofilaria sp. Nematode | CDC EID

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Volume 17, Number 5–May 2011
Dispatch
Human Intraocular Filariasis Caused by Dirofilaria sp. Nematode, Brazil
Domenico Otranto, Daniel G. Diniz, Filipe Dantas-Torres, Maurizio Casiraghi, Izabela N.F. de Almeida, Luciana N.F. de Almeida, Jeannie Nascimento dos Santos, Adriano Penha Furtado, Edmundo F. de Almeida Sobrinho, and Odile Bain

Author affiliations: Università degli Studi di Bari, Bari, Italy (D. Otranto, F. Dantas-Torres); Universidade Federal do Pará, Pará, Brazil (D.G. Diniz, I.N.F. de Almeida, J. Nascimento dos Santos, A. Penha Furtado, E.F. de Almeida Sobrinho); Università degli Studi di Milano-Bicocca, Milan, Italy (M. Casiraghi); Universidade Federal de Minas Gerais, Belo Horizonte, Brazil (L.N.F. de Almeida); and Muséum National d'Histoire Naturelle, Paris, France (O. Bain)


Suggested citation for this article

Abstract
A case of human intraocular dirofilariasis is reported from northern Brazil. The nematode was morphologically and phylogenetically related to Dirofilaria immitis but distinct from reference sequences, including those of D. immitis infesting dogs in the same area. A zoonotic Dirofilaria species infesting wild mammals in Brazil and its implications are discussed.

Zoonotic filariases are caused by nematodes of the superfamily Filarioidea and are transmitted by blood-feeding arthropods. Within this taxonomic group, nematodes of the genus Dirofilaria are among the most common agents infecting humans (1–5). The 2 main species of zoonotic concern are Dirofilaria immitis, which causes canine cardiopulmonary disease, and D. repens, which is usually found in subcutaneous tissues. In addition, zoonotic subcutaneous infections with D. tenuis in raccoons and D. ursi in bears have been reported less frequently in North America (3). Dirofilaria spp. infections in humans have been detected mostly in subcutaneous tissue and lungs (3), and 1 intraocular case of infection with D. repens was reported from Russia (1). D. immitis and D. repens are the main causes of human dirofilariasis in the Americas (4,6) and Old World (2,5), respectively.

Morphologic identification of Dirofilaria spp. is based on the body cuticle, which is smooth in D. immitis (subgenus Dirofilaria) and has external longitudinal ridges in D. repens and other species of the subgenus Nochtiella. However, in many reported cases of zoonotic dirofilariasis, specific identification was not adequately addressed (5). Twenty-eight cases of human dirofilariasis in the Old World attributed to D. immitis have been reviewed recently and attributed to D. repens (5). On the basis of this information, the suggestion was made that D. immitis populations have different infective capabilities for humans in the Old and New Worlds (5). However, this hypothesis was not supported by recent genetic comparisons of specimens from the Old World (Italy and Japan) and New World (United States and Cuba) (7; M. Casiraghi, unpub. data).

We report a case of human intraocular dirofilariasis in which a live male Dirofilaria sp. worm was recovered from the anterior chamber of a patient's eye. Morphologic and molecular studies suggested that this zoonotic case of dirofilariasis was caused by a Dirofilaria sp. closely related to D. immitis.

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Filariasis Caused by Dirofilaria sp. Nematode | CDC EID


Suggested Citation for this Article
Otranto D, Diniz DG, Dantas-Torres F, Casiraghi M, de Almeida INF, de Almeida LNF, et al. Human intraocular filariasis caused by Dirofilaria sp. nematode, Brazil. Emerg Infect Dis [serial on the Internet]. 2011 May [date cited].
http://www.cdc.gov/EID/content/17/5/863.htm

DOI: 10.3201/eid1705.100916


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Domenico Otranto, Dipartimento di Sanità Pubblica e Zootecnia, Facoltà di Medicina Veterinaria, Università degli Studi di Bari, Strada Provinciale per Casamassima km 3, 70010 Valenzano, Bari, Italy; email: d.otranto@veterinaria.uniba.it