Hepatozoon canis in hunting dogs from Southern Italy: distribution and risk factors

L Pacifico,A Fioretti,M Santoro,F Buono,M Beall,B Neola,J Buch,J Braff,P Tyrrell,D Piantedosi,R Chandrashekar,E B Breitschwerdt,V Veneziano,G Sgroi

doi:10.1007/s00436-020-06820-2

Abstract

Hepatozoon canis is a hemoprotozoan organism that infects domestic and wild carnivores throughout much of Europe. The parasite is mainly transmitted through the ingestion of infected ticks containing mature oocysts. The aims of the present survey were to determine the prevalence of H. canis in hunting dogs living in Southern Italy and to assess potential infection risk factors. DNA extracted from whole blood samples, collected from 1433 apparently healthy dogs living in the Napoli, Avellino, and Salerno provinces of Campania region (Southern Italy), was tested by a quantitative real-time polymerase chain reaction (qPCR) assay to amplify H. canis. Furthermore, the investigated dog population was also screened by qPCR for the presence of Ehrlichia canis, a major tick-borne pathogen in Southern Italy, in order to assess possible co-infections. Two hundred dogs were H. canis PCR-positive, resulting in an overall prevalence of 14.0% (CI 12.2–15.9). Breed category (P < 0.0001), hair coat length (P = 0.015), and province of residence (P < 0.0001) represented significant risk factors for H. canis infection. The presence of H. canis DNA was also significantly associated with E. canis PCR positivity (P < 0.0001). Hunting dogs in Campania region (Southern Italy) are frequently exposed to H. canis, and the infection is potentially associated with close contact with wildlife. Further studies are needed to assess the pathogenic potential of H. canis, as well as the epidemiological relationships between hunting dogs and wild animal populations sharing the same habitats in Southern Italy.

Highlights

Section Editor: Domenico OtrantoValenzano, Italy 5 Stazione Zoologica Anton Dohrn, Naples, Italy 6 Comparative Medicine Institute, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, USA 7 Osservatorio Faunistico Venatorio - Regione Campania, Naples, ItalyCanine hepatozoonosis is a vector-borne disease (VBD) caused by hemoprotozoan organisms of the genus Hepatozoon, transmitted by ticks (Ixodidae)
The aims of this study were to determine the H. canis prevalence in hunting dogs living in Southern Italy and to assess the potential risk factors associated with infection
Two hundred of the 1433 dogs were H. canis PCR-positive, with an overall prevalence of 14.0% (200/1433; 95% CI 12.2– 15.9%)

Summary

Introduction

Section Editor: Domenico OtrantoValenzano, Italy 5 Stazione Zoologica Anton Dohrn, Naples, Italy 6 Comparative Medicine Institute, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27607, USA 7 Osservatorio Faunistico Venatorio - Regione Campania, Naples, ItalyCanine hepatozoonosis is a vector-borne disease (VBD) caused by hemoprotozoan organisms of the genus Hepatozoon (phylum Apicomplexa: Adeleorina), transmitted by ticks (Ixodidae). Two Hepatozoon species are known to infect dogs and other wild canids: Hepatozoon canis (James 1905) and Hepatozoon americanum (Vincent-Johnson et al 1997). H. canis is widely distributed in several countries of Europe, Asia, Africa, and America, while H. americanum has been reported only from the North American continent (Giannelli et al 2013; Léveillé et al 2019). Transmission to vertebrate hosts occurs through the ingestion of the infected tick vectors, which harbor mature oocysts of H. canis (Baneth 2011); after merogonic phase in dog tissues, micromerozoites invade the neutrophils and monocytes, where they mature into gamonts that represent the infective stage for the tick (Baneth et al 2007). In contrast to H. americanum, the transmission by ingestion of H. canis monozoic cysts from paratenic host during predation has not been demonstrated (Baneth and Shkap 2003; Baneth 2011)

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