Hаematologic indices in clinically healthy outdoor dogs exposed to vector-borne pathogens

Filip Janjic,Zorana Milanovic,Kristina Spariosu,Andjelo Beletic,Nenad Andric,Jelena Ajtic,Anja Ilic-Bozovic,Milica Kovacevic-Filipovic

doi:10.2298/vetgl191216005j

Abstract

Haematologic abnormalities possibly associated with exposure to vector-borne pathogens are rarely reported in clinically healthy outdoor dogs. Therefore, we analysed changes in the complete blood count (CBC) of clinically healthy outdoor dogs seroreactive to Anaplasma spp. and Babesia spp., with or without microfilariosis. Stray, shelter and hunting dogs, 81 in total, that were polymerase chain reaction negative for Anaplasma spp. and Babesia spp. were divided into groups according to their seroreactive status and results of a modified Knott?s test: seronegative to both Anaplasma spp. and Babesia spp. SN (N=26); seroreactive to A. phagocythophilum SR-A (N=12); seroreactive to B. canis, B. gibsoni and/or B. vogeli SR-B (N=25); and seroreactive to both of the pathogens SR-AB (N=8). These four groups were negative to microfilariosis, unlike the fifth group, seroreactive to either or to both of the pathogens and with microfilariosis SR-M (N=10). The frequencies of CBC alterations among all analysed dogs were: 0.35 ? leucocytosis, 0.44 ? granulocytosis, 0.28 ? anaemia, 0.74 ? microcytosis, 0.37 ? increased mean cell haemoglobin concentration (MCHC) and 0.33 ? thrombocytopenia. The frequency of alterations did not differ across the groups. An exception was the SR-M group wherein increased MCHC peaked with a frequency of 0.80, while in the other four groups, the frequency ranged between 0.10 and 0.50. Clinically healthy outdoor dogs have multiple CBC abnormalities, consistent with stress and low-level chronic inflammation, but not associated with a previous exposure to Anaplasma spp. or Babesia spp. The presence of microfilaria increases haemolysis in vitro.

Highlights

The epidemiology of canine vector-borne pathogens (VBPs) is commonly investigated in asymptomatic outdoor dogs in Serbia (Gabrielli et al, 2015; Obrenović et al, 2015).t Often, the studies included shelter, and stray and hunting dogs (Spasojević-Kosić s et al, 2015)
Exposure to various vectors and VBPs is rather common in these dogs because they spend most of the time in a natural environment without any appropriate ir protection against vectors and parasites
L Our aim was to investigate the frequency of the above-mentioned changes in the complete blood count (CBC) of clinically healthy outdoor dogs that were polymerase n chain reaction (PCR) negative but seroreactive to Anaplasma spp., Babesia spp., with O and without microfilariosis

Summary

Introduction

The epidemiology of canine vector-borne pathogens (VBPs) is commonly investigated in asymptomatic outdoor dogs in Serbia (Gabrielli et al, 2015; Obrenović et al, 2015). T Often, the studies included shelter, and stray and hunting dogs (Spasojević-Kosić s et al, 2015). Conducted in Serbia showed that a population of outdoor dogs were a significant source of potential hosts for several VBPs. F studies on prevalences of VBPs in clinically healthy dogs are numerous, only some of them assessed the health status of the animals (Spasojević-Kosić et al, 2015). Apart from the possible specific pathogenic effect that is associated with e blood cell tropism of VBPs, it is highly possible that frequent exposure to vectors and pathogens causes low-grade tissue damage that could lead to an asymptomatic chronic in inflammation (Otranto et al, 2009). It could be assumed that, as a consequence, haematologic changes consistent with a chronic inflammation, e.g. mild leucocytosis, microcytic anaemia and variable findings in the number of thrombocytes, could be induced

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Results