Subconjunctival Infection with Dirofilaria Repens

Abstract

The first case of Dirofilaria repens (D. repens) parasite in Turkey was detected by Unat in 1944, 1 and human infection with D. repens in the subconjunctiva was also first reported from Adana in 1993 by Soylu et al. 2 Since then, no other cases of human subconjunctival infection with D. repens have been reported in this region.D. repens is a mosquito-borne filaria, a parasite of the subcutaneous tissue of domestic and wild carnivores such as dogs, cats and foxes. 3 Dirofilaria species may be divided into two groups: subgenus Dirofilaria represented by Dirofilaria immitis, which is charecterized by a relatively smooth cuticle and normally found in the right heart and pulmonary vessels of dogs, the natural hosts; and subgenus Nochtiella, which parasitize the subcutaneous tissue. Species of this group have longitudinal ridges on the cuticle. Representative species are Dirofilaria (Nochtiella) repens found in dogs and cats, and Dirofilaria (Nochtiella) tenius found in racoons. 4 As there are no racoons in Turkey, this parasite is not found here. 2 The mature D. repens live in the tissues and organs of vertebrates, while their immature stages prefer the blood and lymph vessels. D. repens is a subdermal parasite in dogs. It has been proven that the parasite, called D. conjunctivae and normaly found in humans, is not a different species from D. repens. 5,6 The main cause of D. conjunctivae cases is D. tenius, which occurs mostly in America, and D. repens, which occurs mostly in Europe (especially in the southern and eastern parts), Russia and Sri Lanka. 5 İt is reported that D. conjunctivae is the immature type of D. repens, therefore, the main infection source of human dirofilariosis is dogs having Dirofilaria. 2,5 D. repens infection, rarely seen in humans, is a zoonotic illness. Humans get infected through blood-sucking arthropods such as mosquitoes, fleas and ticks. During blood sucking, these arthropods receive the immature stages of the parasite called microfilaria. After becoming mature in the arthropods' body, microfilaria is transferred into human or other vertebrates by the blood-sucking arthropods. For D. repens settling in the subconjunctiva, the human body is not an appropriate host, and therefore, no mature stages of the parasite are found in humans. 5 The correct diagnosis of the parasite is usually made with histological examination, based on the identification of the nematode, using the morphological characters of the species to differentiate it from the other Dirofilariae. 5 It is important to identify D. repens by microscopic evaluation of tissue cross section, as well as through its macroscopic characteristics. 7,8 The dyes used in examining the cross transverse sections are hematoxylin-eosin (HE)

Human ocular dirofilariosis in Slovakia, a case report

“…Symptoms usually appear weeks after the infection with third larval stage. Pain in the eye, redness and swelling of eyelids represent symptoms that occurred in our patient and most patients with ocular dirofilariosis (Koltas et al, 2002;Yehudit et al, 2006;Raniel et al, 2006;Janjetović et al, 2010;Khoramnia & Wegner, 2010;Wesolowska et al, 2010). As observed by other authors, visual status usually remained intact after surgical removal of the worm (Koltas et al, 2002;Maraghi et al, 2006;Mittal et al, 2008;Argy et al, 2011;Otranto et al, 2011a;Otranto et al, 2011b).…”

“…Pain in the eye, redness and swelling of eyelids represent symptoms that occurred in our patient and most patients with ocular dirofilariosis (Koltas et al, 2002;Yehudit et al, 2006;Raniel et al, 2006;Janjetović et al, 2010;Khoramnia & Wegner, 2010;Wesolowska et al, 2010). As observed by other authors, visual status usually remained intact after surgical removal of the worm (Koltas et al, 2002;Maraghi et al, 2006;Mittal et al, 2008;Argy et al, 2011;Otranto et al, 2011a;Otranto et al, 2011b). Diagnosis of human dirofilariosis is primarily based on histological evaluation of infected tissue and the macroscopic characteristics of the worm (Rouhani & Athari, 2003;Nath et al, 2010;Tafti et al, 2010;Argy et al, 2011;Otranto et al, 2011b).…”

Discrete eyelid swelling caused by live subconjunctival Dirofilaria repens

“…Ocular Dirofilaria repens may have subconjunctival [5][6][7][8], orbital, intravitreal [3,[9][10][11][12][13][14][15][16][17], and subcutaneous locations, such as intrapalpebral locations [5,[18][19][20][21][22] even in the lacrimal gland [23]. The number of cases of ocular filariasis in the Balkans is increasing [3,[24][25][26][27][28].…”