Geographic distribution of canine heartworm (Dirofilaria immitis) infection in stray dogs of Eastern Romania

Abstract

A survey was conducted in the eastern part of Romania to assess theprevalence and geographical distribution of Dirofilaria immitisindogs. Plasma samples were collected from 458 stray dogs hosted inshelters in 8 counties and tested serologically for the presence ofheartworm. In addition, 45 blood samples from dogs of a shelter inGalati city were examined by the modified Knott and multiplex poly-merase chain reaction (PCR) techniques. The immmunological assayshowed a heartworm infection prevalence of 8.9% in the dogs. Opticaldensity results for positive samples ranged between 0.217 and 2.683.Geographical information systems (GIS) were used to produce over-lays of distribution maps of D. immitisprevalence and predictive mapsbased on temperature suitability. High prevalence of D. immitiswasfound in the central East up to the northern border of the country, i.e.Galati county (60%), followed by the counties of Vaslui (12.0%) andIasi (7.7%). Out of 45 samples examined using the Knott test, 23 werepositive for circulating microfilariae (51.1%), while 19 dogs were pos-itive for D. immitisand 4 for both D. immitis andD. repens with themultiplex PCR test. The high prevalence for D. immitisshown in dogsin the Southeast (Galati, 42.2%) also by multiplex PCR gave strongsupport to the results achieved by the serological tests. The presentstudy confirms the ability of GIS to predict the distribution and epi-demiology of dirofilariosis in different geographical territories as hasbeen already demonstrated by the empirical epidemiological dataobtained at the continental, national and intraregional levels.