The first report on Hepatozoon canis in dogs and wolves in Poland: clinical and epidemiological features

Abstract

Background Canine hepatozoonosis caused by Hepatozoon canis is a common infection in dogs, with frequent case reports from the Mediterranean region and more recently from several Central European countries, such as Hungary and Germany. Despite the high prevalence of H. canis in red foxes, no infections have been reported to date in dogs in Poland. We describe here the first autochthonous cases of H. canis infection in dogs, including their clinical features, and report the prevalence of H. canis in grey wolves from different regions of Poland. Methods Thin smears prepared from blood samples collected from dogs were evaluated by microscopic examination. A total of 60 wolves and 47 dogs were tested. Infections were confirmed by PCR and sequencing. Results Gamonts of H. canis were found in > 50% of the neutrophils of two dogs and in < 10% of the neutrophils in another five dogs. Molecular typing by PCR sequencing of the 18S ribosomal RNA gene fragment confirmed infections in 11 dogs from different regions of Poland, in 2.7% of dogs attending veterinary practices in central Poland and in 35% of wolves from various geographical regions of Poland. Clinical features manifested mostly in older dogs, and the most common signs were anaemia and apathy. Young dogs usually remained asymptomatic. Conclusions This is the first report of H. canis infection in dogs and wolves in Poland. Although the exact vector of the parasite is not known, veterinary practitioners should be aware of this new parasitosis and should consider appropriate diagnostics to confirm/exclude this infection. Further studies are needed to understand the transmission routes of H. canis in domestic and wild canids in Poland. Graphical Abstract

Hematological and plasma profiles and ticks and tick-borne pathogens in wild Formosan black bears (Ursus thibetanus formosanus)

“…gamonts in the blood of bears with high ESR and globulin values. Notably, changes in albumin, globulin, and ALP levels have also observed in other Babesia -infected hosts, such as camels ( Camelus dromedarius ) [ 53 ], dogs ( Canis familiaris ) [ 54 ], and cattle [ 55 ] as well as Hepatozoon -infected dogs [ 56 – 58 ]. Collectively, these hematological and plasma data may serve as a reference for future investigation on host and tick-borne pathogen relationships in wild bears.…”

Vector-borne diseases imported to Poland between 2021 and 2023

“…So far, data on the occurrence of these diseases in dogs in Poland are fragmentary. The first cases of hepatozoonosis caused by Hepatozoon canis invasions in Poland were described in 2021–2022 ( 50 ). The infected dogs came to Poland from Ukraine (together with refugees) ( 9 ), but there were also dogs suffering from it which had never left Poland (autochthonous cases) ( 50 ).…”

“…Poland is a country where vector-borne diseases such as babesiosis (caused by Babesia canis ), granulocytic anaplasmosis and Lyme disease are relatively frequently diagnosed in dogs ( 55 , 56 ). In recent years, isolated cases of infections with Babesia gibsoni ( 47 ), Hepatozoon canis ( 50 ), Leishmania infantum ( 18 , 41 ) and Dirofilaria immitis ( 29 ) have also been observed. This may be a consequence of the increased frequency of tourist trips with pet dogs to countries where these diseases occur.…”

Molecular Survey of Hepatozoon canis Infection in Domestic Dogs from Sardinia, Italy

“…However, it was shown that dogs naturally infected with H. canis showed no clinical signs of the parasite despite its presence being confirmed by PCR tests and cytology [15]. Furthermore, eosinophilia, leukocytosis, lymphocytosis, neutrophilia, and other hematological abnormalities were present in almost all dogs analyzed [17].…”