Short communication

Several cases of dirofilariosis accidentallydiagnosed in dogs from Poland, includingtwo PCR positive Dirofilaria repens cases

R. Sapierzyński1, M. Fabisiak1, A. Sałamaszyńska2

1 Department of Clinical Sciences,2 Department of Preclinical Sciences, Faculty of Veterinary Medicine,

Warsaw University of Life Sciences (SGGW), Nowoursynowska 159c, 02-766 Warsaw, Poland

Abstract

The aim of the present study was a description of several microfilaremia cases diagnosed in dogsfrom Poland. The study was conducted on cytological samples of pathologic masses and peripheralblood smears taken for diagnostic purposes from dogs showing a various clinical findings. The pres-ence of the parasites in tissue samples was observed in 8 dogs, additionally, in 2 of these dogs PCRanalysis of blood samples revealed the presence of D. repens DNA.

Key words: cytology, Dirofilaria repens, dog, microfilariosis

Introduction

When reviewing different published sources forveterinary practitioners it is possible to meet a con-siderable amount of information about dirofilariosisin Poland, however, these repeating data mostly seemuncertain or are not supported sufficiently by respect-able diagnostic methods (Demiaszkiewicz andPolańczyk 2010). There are descriptions of cases ofcanine and human Dirofilaria infection accidentallybrought to Poland and countries as Germany, CzechRepublic and Slovakia (Svobodova et al. 2006,Cielecka et al. 2007, Miterpakova et al. 2009, Pan-tchev et al. 2009). In subcutaneous dirofilariosis, inthe blood of infected animals larval forms of parasiteare often observed, which are formed by an adult indi-vidual (female) that inhabits the subcutaneous andconnective tissue. The aim of the present study wasa description of several diagnosed microfilariemiacases in dogs from Poland.

Correspondence to: R. Sapierzyński, e-mail: rafal–sapierzynski@sggw.pl

Material and Methods

The study material consisted of cytologicalsamples (material taken during fine-needle aspirationbiopsy of dermal lesions or enlarged lymph node)or/and peripheral blood smears taken from 8 dogsshowing a various clinical findings, in which the pres-ence of parasites with morphology of microfilaria wasaccidentally discovered. In 6 out of 8 dogs after para-site detection another sample of 4 ml of blood onEDTA was taken for further hematological (Giemsastained smears evaluated in a light microscope) andDNA analysis (PCR). The PCR protocol was per-formed according to that reported by Rishniw et al.(2006) with primers targeting the internal transcribedspacer region 2 (ITS 2) of the ribosomal DNA andcytochrome oxidase subunit 1 (COI) gene for D. im-mitis, and the 5S ribosomal intergenic region and COIgene for D. repens.

Polish Journal of Veterinary Sciences Vol. 13, No. 3 (2010), 545-547

Results and Discussion

The presence of microfilariae was observed inmicroscopic samples of 8 dogs (Fig. 1). Moreover, in6 out of 8 animals examination, of additional periph-eral blood smear confirmed the presence of the para-sites. The indications for the primary examination inwhich the parasite was accidentally detected, samplesource, and confirmation methods results of micro-filaria presence in the peripheral blood are sum-marized in Table 1. PCR positive reaction for D. re-

Fig. 1. Dirofilaria repens larvae in peripheral blood smear obtained from dogs with apocrine gland adenocarcinoma (parasitespecies confirmed by PCR). Material obtained by fine-needle aspiration biopsy (Giemsa stain, magnification 1000x).

Table 1. Indications for the primary examination in which parasite was accidentally detected, sample source, and results ofconfirmation method for the presence of microfilaria in the peripheral blood in investigated the dogs.

Indications for the primary examinationand sample sourceLp. Confirmation tests Diagnosis/remarks

1. FNAB of subcutaneous tumour PBS, LM Mast cell tumour2. FNAB of mammary gland tumour PBS, LM, PCR Apocrine gland adenocarcinoma3. Lymph node FNAB NE Lymphoma4. FNAB of subcutaneous tumour PBS, LM Chronic subdermal inflammation5. Histopathological examination of subcutaneous PBS, LM, PCR Identification of adult parasite in paraffin tissue

tumour – presence of adult parasite block, subcutaneous nodule6. PBS – blood control preceding rhinoscopy PBS, LM Chronic rhinitis and sinusitis – presence

of microfilariae in microscopic slides7. PBS – leukemia suspicion NE Lymphocytosis, transient hind limbs oedema8. PBS – examination towards Babesia canis PBS, LM Severe haemolytic anemia

FNAB – fine-needle aspiration biopsy, PBS – Peripheral blood smear, LM – Light microscopy, NE – not examined

pens was obtained in samples No. 2 and No. 5. Infec-tions were considered native because none of the dogswas travelling abroad. In Germany, Dirofilaria wasdiscovered in peripheral blood in 6.8% of 44 testedhunting dogs (Pantchev et al. 2009). Recently, data ondirofilariosis (caused by Dirofilaria repens) conductedon a large military and police dogs population re-vealed dirofilariosis occurrence of level respectively20% and 8.4% (Miterpakova et al. 2009).

In only one of the cases (No. 5) discussed we wereable to identify the site of invasion of the adult para-

546 R. Sapierzyński et al.

site – it was subcutaneous tissue. In remaining cases,no anamnesis or clinical examination allowed to re-veal the invasion site. Particularly interesting seems tobe the possible relationship between parasite infectionand neoplasia. In our study, in 3 cases the presence ofmicrofilariae in blood was accompanied by malignanttumors. However, it has to be taken into account thatthe presence of tumor (indication to make a biopsy)contributed to accidental discovery of parasites ratherthan that the parasite caused the tumor lesions. Inhumans, it was shown that in a list of various patho-logical states (cysts and granulomas) connected to D.immitis infestation, also primary malignant and be-nign tumors were included.

Based on the present results it seems reasonableto assume that diseases from dirofilariosis groupshould be considered as a potential, differential diag-nosis in companion animals in Poland. Moreover,even in patients without visible clinical signs of theinvasion, it is advised to treat microfilariosis pharma-cologically in a perspective of breaking the epi-demiological chain, and allowing the disease spreadamong wider dog population, and in human popula-tion as well.

References

Cielecka D, Szymańska D, Salamatin R, TomaszewskaA (2007) Case report of human infection with Dirofilariarepens (Leidy, 1856) (Nematoda; Filarioidea: Onchocer-cidae) in Warsaw. Wiadomości Parazytologiczne 53(suppl): 165.

Demiaszkiewicz AW, Polańczyk G (2010) The first case ofDirofilaria repens invasion in a dog in Poland. Mag Weter154: 254-256.

Miterpakova M, Antolova D, Hurnikova Z, Dubinsky P, Pav-lacka A, Nemeth J (2009) Dirofilaria infections in work-ing dogs in Slovakia. J Helminthol 4: 1-4.

Pantchev N, Norden N, Lorentzen L, Rossi M, Rossi U,Brand B, Dyachenko V (2009) Current surveys on preva-lence and distribution of Dirofilaria spp. in dogs in Ger-many Parasitol Res 105 (Suppl): S63-74.

Rishniw M, Barr SC, Simpson KW, Frongillo MF, Franz M,Domoniguez Alpizar JL (2006) Discrimination betweensix species of canine microfilariae by a single polymerasechain reaction. Vet Parasitol 135: 303-314.

Svobodova Z, Svobodova V, Genchi C, Forejtek P (2006)The first report of autochthonous dirofilariosis in dogs inthe Czech Republic. Helminthologia 43: 242-245.

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