Date: Thu 21 Jun 2018
Source: N Engl J Med [edited]
Citation Kartashev V and Simon F. Migrating Dirofilaria repens. N Engl J Med. 2018;378(25):e35. doi: 10.1056/NEJMicm1716138.
A 32-year-old woman presented to an ophthalmologist with a 2-week history of nodules that moved around her face. She had first noted a nodule below her left eye (Panel A) [for images see URL]. Five days later, it had moved to above her left eye (Panel B), and 10 days after that to the upper lip (Panel C). She documented these changes by taking photographs of her face (i.e., "selfies"). The nodules occasionally caused a localized itching and burning sensation, but otherwise she had no symptoms.
She had recently travelled to a rural area outside Moscow and recalled being frequently bitten by mosquitoes. A physical examination showed a superficial moving oblong nodule at the left upper eyelid. A parasite was fixed with forceps and removed surgically (Panel D). The parasite was identified by means of a polymerase-chain-reaction assay as _Dirofilaria repens_, which is a zoonotic filarial nematode.
Dogs and other carnivores are the definitive hosts, and mosquitoes serve as vectors. Humans can become aberrant hosts. Surgical excision of the worm is curative. After removal of the worm, the patient had a full recovery. -- Communicated by: ProMED-mail <firstname.lastname@example.org> [Human infections with _D. repens_ is well known in Russia and a recent review included data from 236 human patients (Ermakova LA, Nagorny SA, Krivorotova EY, Pshenichnaya NY, Matina ON. _Dirofilaria repens_ in the Russian Federation: current epidemiology, diagnosis, and treatment from a federal reference center perspective. Int J Infect Dis. 2014 Jun;23:47-52. doi: 10.1016/j.ijid.2014.02.008).
The reservoir are dogs and the infection is transmitted to humans by mosquitoes and is also described from other European countries (MiterpÃ¡kovÃ¡ M et al. Heartworm on the rise-new insights into _Dirofilaria immitis_ epidemiology.
Parasitol Res. 2018 Jul;117(7):2347-2350. doi: 10.1007/s00436-018-5912-9; Blaizot R et al.
Systemic Infection With _Dirofilaria repens_ in Southwestern France.
Ann Intern Med. 2018 Feb 6;168(3):228-229. doi: 10.7326/L17-0426). - ProMED Mod.EP]
[Until 2014 human dirofilariasis in the Russian Federation was considered as a rare helminthiasis. According to information by the Center of Hygiene and Epidemiology of Rospotrebnadzor, at the end of 2012, 1093 cases infected by _D. repens_ have been recorded in Russian Federation (since 1915, where the 1st case in Russia was recorded). But now, due to the sudden increase of infectious cases, the human dirofilariasis is recording separately from other Helminthiasis in the official statistical reports.
Due to the favorable natural and climatic conditions, as well as the high affection of definitive (dogs and other animals of the family of canines and felines) and intermediate hosts (mosquitoes), the territory of the South of Russia is a risk area for sustainable transmission of infestation. The incidence of human infestation correlated with the extent of infestation in final and intermediate hosts.
Dogs are the most important source for human transmission. The largest number of cases was revealed in the Rostov, Volgograd and Nizhny Novgorod regions. At the beginning of 2013, 242 patients with dirofilariasis were recorded in the Rostov region. This is 22.1 percent of all cases recorded in the Russian Federation. Often patients addressed for medical assistance in hospital due to detection under the skin dense fixed formations, up to 1.5 cm, or in cases of the visualization of thread like moving worms under the skin in various localization.
A migration of the parasite we observed in 43.6 percent of patients. In 17.7 percent of cases, worms moved considerable distances: from the knee to the groin area; lower back, upper eyelid or from periorbital region to shin and buttocks. Common localizations of _Dirofilaria_ were head and neck (most often in the periorbital area, and conjunctivitis (face, scalp and forehead), or more rarely in the area of the trunk and extremities. In 6 patients (2.3 percent), worms were found in the external genitals. - ProMED Mod.NP]
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