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

Emerging risk of Dirofilaria spp. infection in shelter dogs in southern Italy

In southern Italy, the number of autochthonous cases of Dirofilaria immitis in dogs has increased considerably. This also occurs in the Campania region, particularly in coastal areas, where infections with D. immitis and Dirofilaria repens have been reported more frequently. Therefore the aim of the present study was to better investigate the occurrence of Dirofilaria spp. in a local dog shelter in Castel Volturno (Campania region, southern Italy). Briefly, a total of 260 blood samples were analysed for identification of microfilariae (mff) and detection of Dirofilaria immitis antigen. Dogs were classified according to their age (1-3  years; 4-6  years; 7-11  years; > 11  years) and length of stay in the shelter at the time of sampling (dogs that entered in the shelter in the last 4  months; dogs housed in the shelter for more than 4 months up to 2  years; dogs housed for more than 2  years). The modified Knott's test revealed that 195 dogs (75.0%) were positive for circulating mff of Dirofilaria spp. Specifically, 104/260 (40.0%) dogs were positive for D. immitis and 91/260 (35.0%) were positive for D. repens. In addition, 72/260 (27.7%) dogs had both D. immitis and D. repens mff. Antigen testing revealed that 78/260 (30.0%) dogs were positive for D. immitis. However, 26/104 (25.0%) of the dogs with D. immitis mff were antigen-negative. The overall k concordance between the modified Knott's test and the antigenic test was ≤0.2 (poor) (p = 0.000). The results of the logistic regression model showed a significant association between Dirofilaria exposure and the period of time the dogs had spent in the shelter at the time of sampling. Dogs housed in the shelter for 4 months (group 1) and between 4 months and 2 years (group 2) had higher Dirofilaria positivity than dogs in group 3 (housed for more than 2 years) (80.4% vs. 79.6% vs. 62.4%, respectively). Moreover, male dogs and older dogs (between 7 and 11 years of age) were more likely to be infected with Dirofilaria spp.

Identity of Microfilariae Circulating in Dogs from Western and South-Western Romania in the Last Decade

Dirofilaria infections in dogs are recognized as widespread mosquito-borne diseases with zoonotic potential, that are caused by the filarioid nematode (Onchocercidae) species Dirofilaria immitis and Dirofilaria repens. The long-term survey conducted in western and south-western Romania was undertaken in order to provide valuable data on the occurrence of Dirofilaria infections in dogs. Blood samples from 1088 dogs, originating from 73 localities of 11 western and south-western counties in Romania, were collected and examined using the modified Knott test. Subsequently, all of the microscopically positive samples were subjected to molecular analysis for confirmation. Altogether, the data obtained showed the percentage of dogs with circulating microfilariae to be 21.42% (233/1088) of dogs tested in the investigated region. The identified species, in cases of monoinfections, were D. immitis, D. repens, and Acanthocheilonema reconditum in 106 (9.74%) samples, 102 (9.38%) samples, and 1 (0.09%) sample, respectively. Twenty-four (2.21%) samples were simultaneously positive for D. immitis and D. repens. There was no association (p > 0.05) between infection status and breed; however, sex and lifestyle were positively associated (p < 0.05) with the percentage of dogs with circulating microfilariae and might be regarded as risk factors for infection. The results of the present investigation indicate potential zoonotic risks for humans living in the screened area and support the imperative to increase awareness among both veterinarians and physicians, regarding the continuous spread of these zoonotic filariae.