Adult Dirofilaria repens nematodes in a cat from Kiev, Ukraine

First report on natural infection by Dirofilaria repens in a cat in Spain: case report and literature review of feline subcutaneous dirofilariosis in Europe

Dirofilaria repens is an endemic mosquito-borne pathogen widely spread throughout Europe and other non-Europen regions. Infection by D. repens has been reported in dogs, although little is known about the occurrence and epidemiological features of this nematode in cats. During the surgical procedure within the framework of a trap, neuter and release sterilization program, two female filarial nematodes with spontaneous movement were removed from the internal part of the spermatic cord from asymptomatic stray cat in Spain (Grao de Castellón, Castellon de la Plana, province of Spain). Moreover, the presence of microfilariae was detected by using three different methods, including direct blood smear technique, the microhematocrit tube test, and Knott´s modified test. PCR performed from the nematodes extracted from the spermatic cord and from microfilariae in EDTA-blood sample tested both positive for D. repens. To the authors' knowledge, this is the first report that demonstrates the presence of D. repens in cats in Spain. In this sense, a review of the current scientific status of feline subcutaneous dirofilariosis in Europe was also performed. Future investigations should analyze the epidemiological role of cats in D. repens infection including the prevalence of infection. Veterinarians working in endemic areas should be aware of this infection in cats and their susceptibility.

Rare case of Dioctophyme renale (Nematoda: Enoplida) and Dirofilaria sp. (Nematoda: Spirurida) in the subcutaneous tissue of a cat in Espírito Santo, Brazil

Dioctophyme renale is the largest parasitic nematode of animals. It is most often found in the right kidney, but can also occur in the urinary system, ears, free abdominal cavity, mammary gland, thoracic cavity, and more rarely in subcutaneous tissue. The genus Dirofilaria has specific parasitic characteristics according to its location, and may parasitize the respiratory tract or even the skin, varying according to species. This report describes a case of Dioctophyme renale and Dirofilaria sp. in the subcutaneous tissue of a cat in the state of Espírito Santo, Brazil. An adult male mongrel cat showed physical enlargement in the left inguinal region, diagnosed as a subcutaneous nodule. Surgical excision and histopathological evaluation of the nodule were performed, and Dioctophyme renale and Dirofilaria sp. were found inside. Dioctophymosis and heartworm disease are present in Brazil and most other countries, but this is the unprecedented case of the association of Dioctophyme renale and Dirofilaria sp. in the subcutaneous tissue of a cat.

First report of Dirofilaria repens infection in a microfilaraemic cat from Romania

The present study describes the first report of Dirofilaria repens infection with the presence of both microfilariae and adult nematodes in a cat from Northeastern Romania. Briefly, a 5-year-old male mixed breed cat was presented to a veterinary clinic in Iasi (Romania), for neutering, in early February 2020. During the surgery, two whitish worms were removed from the internal part of the scrotum. Two adult nematodes, one female and one male, were identified, on the basis of morphological features, as D. repens with whitish, cylindrical bodies, measuring 12.5 cm and 6.5 cm in length, respectively. At histology, the female nematode showed two cavitated structures containing myriads of variably arranged microfilariae. The male had a transversal diameter of 350 μm, a 10 μm thick cuticle and a ridge-period of 10 Μm. multiplex PCR confirmed the diagnosis of D. repens from both nematodes. The Knott's test revealed the presence of microfilariae of D. repens. Routine biochemistry panel was within range with one exception, urea serum level slightly increased. The haematology results revealed an increased number of neutrophils, lymphocytes and eosinophils. The cat had an infection with Otodectes cynotis as well. The cat was discharged with the following therapy recommended: oral doxycycline (10 mg/kg) for 30 days and topical moxidectin, monthly doses. After six months, the Knott's test gave negative results. Further studies should include new insights of D. repens infection in cats concerning its epidemiology, diagnosis and control.

Dirofilarioses in cats: European guidelines from the ABCD on prevention and management

OVERVIEW

Dirofilaria immitis and Dirofilaria repens are the most important filarial worms, causing heartworm disease and subcutaneous dirofilariosis, respectively. D repens is currently considered an emerging zoonotic agent in Europe.

LIFE CYCLE AND INFECTION

Filarial worms infect mainly dogs, but also cats, ferrets, wild carnivores and humans. The life cycle involves an intermediate mosquito host. Compared with dogs, cats are imperfect hosts for dirofilarial worms. After inoculation, only a low number of L3 larvae develop to the adult stage in a small percentage of cats. Heartworm disease in cats may be associated with severe pulmonary thromboembolism and an eosinophilic inflammatory response in the lungs, potentially leading to sudden death. Otherwise self-cure occurs in most cases after 18-48 months. Subcutaneous dirofilariosis may present as subcutaneous nodules or dermatitis.

DIAGNOSIS AND TREATMENT

Diagnosis in cats is more difficult compared with dogs and needs a multistep approach (antigen and antibody tests, as well as diagnostic imaging). Cats with acute heartworm disease require stabilisation within an intensive care unit. Cats with respiratory signs or suggestive radiographic changes should receive prednisolone and follow-up with a similar multistep approach. Adulticidal therapy is not safe in cats.

PREVENTION

In endemic areas cats should receive year-round chemoprophylaxis from 2 months of age.

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.

Vector-borne pathogens in ticks and EDTA-blood samples collected from client-owned dogs, Kiev, Ukraine

Due to the availability of adequate habitats in urban environments, e.g. city parks and recreational green areas, ticks from such settings may also carry pathogens of veterinary and public health concern. Thus, tick-borne infections may readily be identified in companion animals residing in urbanised areas. To investigate the presence of vector-borne pathogens in Kiev, Ukraine, 52 engorged adult ticks, 33 Dermacentor reticulatus and 19 Ixodes ricinus, were collected from 15 dogs in the spring of 2010, and further 23 canine EDTA-blood samples were obtained in the spring of 2011 from client-owned patients presented in a veterinary clinic in Kiev. DNA of 9 pathogens was detected by PCR in ticks and canine EDTA-blood samples: Babesia canis canis, Anaplasma phagocytophilum, Rickettsia helvetica, Ri. monacensis, Ri. raoultii, and Dirofilaria repens (by proxy) were identified in engorged ticks and B. c. canis, Hepatozoon canis, Di. immitis, Di. repens, and Mycoplasma haemocanis in canine EDTA-blood samples. This is the first description of Ri. raoultii in the Ukraine. This study adds information on the occurrence of vector-borne pathogens of veterinary and public health importance in Kiev, Ukraine.

Clinical Aspects of Dermatitis Associated with Dirofilaria repens in Pets: A Review of 100 Canine and 31 Feline Cases (1990-2010) and a Report of a New Clinic Case Imported from Italy to Dubai

Cutaneous dirofilariasis is a parasitic disease caused by the mosquito-borne filarial nematodes Dirofilaria (Nochtiella) repens, living in the subcutaneous tissue of dogs, cats, wild carnivores, and humans. Cases have been recently reported also from Germany, Czech Republic, Hungary, Ukraine, Russia, Austria, Switzerland, France, The Netherlands, and the Middle East. D. repens is not widely known to cause chronic pruritic dermatitis in animals. Dermatological signs observed in 100 canine clinic cases were pruritus (100%), erythema (79%), papulae (62%), focal or multifocal alopecia (55%), hyperkeratosis (18%), crusting (14%), nodules (12%), acantosis (5%), and eczema (3%). Signs other than dermatological were conjunctivitis (46%), anorexia (35%), vomiting (26%), fever (25%), lethargy (20%), and lymph-adenomegaly (10%). A case imported from Italy to Dubai is described. The opportunistic role of D. repens might explain the presence of asymptomatic carriers, the concurrent observation of nondermatological signs, and the development of dermatitis in a subgroup of parasitized dogs.

A Case of Orbital Dirofilariasis in Northern Turkey

A 29-year-old male patient presented with complaints of a localized mass behind his right lower eyelid that had been present for the last 6 months. Ophthalmologic examination was completely normal except for a 2 cm x 2 cm painless mass localized on the inferior orbital rim behind the right lower eyelid. An excisional biopsy was planned, and an anterior orbitotomy was performed by a lateral canthotomy and inferior cantholysis. Premature rupture of the cyst occurred during dissection, disclosing a thin white parasite surrounded by copious purulent material. The parasite and surrounding cyst were submitted to laboratory for evaluation. The parasite was typed as Dirofilaria repens (13 cm, female). The patient remained symptom-free over the 4 months of postoperative follow-up. Detection of the first human case of orbital dirofilariasis in Northern Turkey, in a patient with no history of travel to any endemic areas, has raised questions about the parasite's zoonotic characteristics.