Dirofilaria repens infection in a dog imported to Norway

Dirofilaria repens infection was diagnosed in a dog that had been imported to Norway from Hungary three years previously. The dog was a four-year-old castrated male mixed-breed dog and presented for examination of two masses on the right thoracic wall. Fine needle sampling from the subcutaneous nodules and subsequent cytological examination revealed a high number of microfilariae and a pyogranulomatous inflammation. At re-examination approximately 3 weeks later, both masses had apparently disappeared spontaneously, based on both inspection and palpation. However, examination of peripheral blood by a modified Knott’s test revealed a high number of unsheathed microfilariae with mean length of 360 μm and mean width of 6-7 μm, often with the classic umbrella handle appearance of D. repens. Polymerase chain reaction and sequencing confirmed the D. repens diagnosis. Subcutaneous dirofilariosis caused by D. repens is probably the most common cause of human zoonotic dirofilariosis in Europe, but currently is rarely encountered in northern countries such as Norway. However, travelling, import and relocation of dogs have increased, and thus the geographical range of these parasites is likely to increase from traditionally endemic southern regions. Increasing numbers of autochthonous cases of D. repens infections in dogs have been reported in eastern and central Europe. Although infection with D. repens often induces only mild signs or subclinical infections in dogs, they nevertheless represent a reservoir for zoonotic transmission and thus a public health concern, and, in addition, due to the long prepatent period and the high frequency of subclinical infections or infections with unspecific clinical signs, could easily be missed. Lack of experience and expectation of these parasites may mean that infection is underdiagnosed in veterinary clinics in northern countries. Also, predicted climate changes suggest that conditions in some countries where this infection is currently not endemic are likely to become more suitable for development in the intermediate host, and thus the establishment of the infection in new areas.     

Subconjunctival Dirofilaria repens infection in a dog resident in the UK

Dirofilaria repens infection was diagnosed in a 5‐year‐old female German shepherd crossbreed, originally from Romania but brought into the UK in February 2014. The dog presented with conjunctivitis in March 2014 and then again 2 months later with additional ocular and nasal mucopurulent discharge. Bacterial cultures from the nasolacrimal duct were negative for bacterial growth. The case was referred in August 2014 for ophthalmic examination, which revealed abnormalities in both eyes, especially the left. They included mild palpebral conjunctival hyperaemia and marked follicular conjunctivitis, as well as a dorsonasal bulbar conjunctival mass. Serum biochemistry was unremarkable and a conjunctival biopsy taken from the dorsonasal bulbar conjunctival mass revealed eosinophilic/lymphoplasmacytic conjunctivitis. At re‐examination, nematodes were found in the area of the previous biopsy site and in the ventral palpebral conjunctival fornix. Polymerase chain reaction and sequencing confirmed these to be D. repens. Treatment with 10% imidacloprid and 2·5% moxidectin (Advocate Spot‐On) was successful, and clinical signs resolved over a 6‐week period. This case report indicates that D. repens infection should be considered as a possible aetiological cause of ocular lesions in dogs in the UK, especially those with a history of foreign travel. Implications for establishment and spread of D. repens in the UK are discussed.     

Unusual localization of Dirofilaria repens (Spirurida: Onchocercidae) infection in the testicle of a dog

This report describes an uncommon localization of Dirofilaria repens in the testicle of a nine-year-old dog from southern Italy. The dog underwent neutring and three adult nematodes were found in the tunica vaginalis. At gross anatomy, no pathological changes were observed on the tunica, in the testicle or epididymis. The parasites, one female and two males, were morphologically and molecularly identified as D. repens. This is the first report of D. repens in the canine testicle in Italy. This case report highlights the asymptomatic nature of D. repens infection, suggesting that dogs living in endemic areas may act as silent carriers. Careful screening and an effective chemoprophylaxis should be ensured for all animals potentially exposed to D. repens infection in order to reduce the risk of infection to humans in areas where the parasite is endemic.     

Adult Dirofilaria repens in a subcutaneous granuloma on the chest of a dog

A 10-year-old, 9 kg, intact male crossbred dog was treated for nasal mites with milbemycin oxime using a dose of 1 mg/kg bodyweight orally, three times at 10-day intervals. One month after the initiation of this treatment a subcutaneous nodule developed on the sternum of the dog. The nodule was removed and found to contain a single, 82 mm long, thread-like nematode. Several exotic parasites were suspected as possibilities because the dog had been imported to Norway from South Africa. Microfilariae were not detected in the blood and heartworm antigen tests were negative. The worm was identified morphologically as an adult, female Dirofilaria repens. This is the first report of D repens from Norway. The case is of interest because of the differential diagnostic problem it posed and because infestation was recognised following treatment of another parasitic condition with a broad-spectrum, antiparasitic drug. In addition, the case provides a reminder of the necessity to be aware of geographical differences in disease occurrence which can produce unexpected disease in non-endemic areas as a consequence of increased international travel with pets.     

Neurologic complications after melarsomine dihydrochloride treatment for Dirofilaria immitis in three dogs

Melarsomine dihydrochloride is highly effective against both sexes of adult and L5 Dirofilaria immitis. Common adverse reactions include injection site irritation and reluctance to move. Neurologic complications associated with i.m. injection of melarsomine dihydrochloride for treatment of heartworm disease in 3 dogs are described. Different degrees of neurologic complications have been identified; the pathophysiologic features are unknown. It is speculated that the compound migrates out of the injection site via fascial planes and causes an ascending inflammation along nerve roots. The resulting extradural cord compression secondary to extensive inflammation and necrosis of epidural fat could induce a variety of neurologic deficits. Alternatively, inappropriate injection technique may result in direct contact of melarsomine with neural tissue. A heightened awareness of proper injection technique might prevent the development of most neurologic complications.     

Nodular presentation of Dirofilaria repens infection in a cat mimicking a fibrosarcoma

A cat with multiple subcutaneous nodules suggesting a soft tissue sarcoma by physical and computed tomographic examination was diagnosed as being affected by subcutaneous filariosis based on cytologic and ultrasonographic assessments. Nodules were surgically removed and extracted nematodes were identified by PCR as Dirofilaria repens. Furthermore, DNA of Dipetalonema dracunculoides (syn. Acantocheilonema dracunculoides) was detected by PCR, with no evidence of circulating microfilariae. To the best of the authors' knowledge, this represents the first report describing adults of D repens in multiple subcutaneous nodules in a cat. Cytopathologic examination allowed characterization of the parasitic nature of the nodules. Veterinary practitioners should be aware of the possible nodular presentation of D repens in cats and should include D repens in the differential diagnosis of subcutaneous neoformations in the cat.     

Dirofilaria repens in a cat with acute liver failure

Acute liver failure was diagnosed in a 12-year-old cat. Fine needle aspirate cytology revealed high numbers of unsheathed microfilariae and a hepatocellular reaction with no evidence of bacterial infection. The microfilariae were identified as those of Dirofilaria repens by acid phosphatase staining. The high number of microfilariae seen in both the blood and the liver aspirate samples as well as the favourable response to ivermectin amongst other drugs administered, is suggestive that D. repens was the cause of the liver insult. A positive result obtained with an antigen-capture ELISA (Dirochek) for Dirofilaria immitis antigen was interpreted as false. This is the 1st report of Dirofilaria repens for South Africa.     

Autochthonous Dirofilaria (Nochtiella) repens infection in dogs in Kuwait

Human dirofilariasis caused by Dirofilaria repens is a rare but increasingly reported zoonosis in the Middle East. However, eligible animal reservoirs seldom have been investigated in the area until now. Seven (1.8 percent) out of 381 dogs examined in Kuwait carried D. repens microfilariae showing compatible cutaneous clinical signs and positive response to the adulticide and microfilaricide therapies. This study indicates that dogs from Kuwait are natural hosts of D. repens and therefore act as an animal reservoir for the zoonotic condition.     

Glomerulonephritis associated with simultaneous canine adenovirus-1 and Dirofilaria immitis infection in a dog

This article describes a case of glomerulonephritis and immunocomplex (IgM, IgG and C3c) deposition in the mesangium and basement membranes of a 2-year-old dog with canine viral hepatitis and dirofilariasis. The deposits observed in the mesangium were in the vicinity of cells with viral replication. However, no clear relationship was found between viral replication and the deposition of immunocomplexes in the glomerular capillary basement membranes, which may be the reason why these deposits have only been tentatively related to the concomitant infestation by Dirofilaria immitis.     

Human Dirofilaria repens infection in Hungary: a case in the spermatic cord and a review of the literature

Orchiectomy was performed in a 37-year-old Hungarian man exhibiting a swelling in his right testicle. Histology revealed a nodule attached to the spermatic cord, consisting of a granulomatous tissue around sections of a nematode. The worm was identified as Dirofilaria repens, an uncommon parasite in Hungary. As the patient had been abroad only in Italy where cases of dirofilariosis in dogs and humans are relatively frequent, it is assumed that the infection might have been acquired in that country 5 years earlier. This is the fifth case, published so far in the world, of such a localization in a human. The human cases of dirofilariosis reported in Hungary are reviewed.     

Nodular skin disease associated with Dirofilaria immitis infection in the dog.

Three dogs with dirofilariasis had a dermatologic syndrome, characterized by pruritus and multifocal nodules which tended to ulcerate. The cutaneous nodules revealed angiocentric pyogranulomatous inflammation with variable numbers of eosinophils. Microfilariae were often present in the blood vessels surrounded by the pyogranulomatous process. Therapy for dirofilariasis resulted in complete resolution of the dermatitis.     

Dermatitis associated with Dirofilaria repens microfilariae in three dogs in Saudi Arabia

The presence of microfilariae of the zoonotic nematode Dirofilaria repens is reported in three dogs from Saudi Arabia, manifesting as pruritic dermatitis with signs including erythema, alopecia, papules, crusting and hyperkeratosis. All dogs were found to have concurrent babesiosis. Specific treatments against the two conditions led to complete clinical recovery and disappearance of microfilariae from the blood one month later.     

Autochthonous canine Dirofilaria repens in the vicinity of Warsaw

In 2009 microfilaremia was recognized in ten dogs living in five distinct districts located near Warsaw, the capital of Poland. Based on PCR results, all the animals were found to be infected with Dirofilaria repens. Nine of the infected dogs have never travelled outside the country and it was assumed that the cases were native. Monitoring the infection in the European countries should be introduced to establish the actual geographic range of dirofilariosis.