Cancer morbidity in Croatian cats: Retrospective study on spontaneously arising tumors (2009-2019).

One of the current leading causes of death in pet cats is neoplasia. The scarcity of data on tumor prevalence in cats from south-eastern Europe led to this retrospective study which reports an abundant collection of tumors diagnosed in cats living in Croatia. Archived histopathology findings (diagnosis, cell origin, and biological behavior), and epidemiological data (breed, sex, age, and anatomical site of the tumor) of the cats diagnosed with at least one tumor were collected and statistically analyzed. For the research, 2338 archived feline samples, obtained from 2009-2019, have been reviewed. In 659 samples (28.1%) one or more tumors were diagnosed. Tumors have most often affected non-pedigree cats, cats between 7 and 15 years of age, and female cats. Most tumors showed malignant behavior (85.7%). The most frequent diagnoses were mammary adenocarcinoma, lymphoma, and squamous cell carcinoma. Regarding origin, most samples were epithelial (46.9%), but mesenchymal (28.7%) and lymphoid tumors (17.0%) were also frequently found. Tumors most often occurred in the skin and subcutis, mammary gland (in females), digestive system, and hemolymphatic system (in males). Statistical analysis did not reveal breed, sex, and age predisposition, but female animals and non-pedigree cats were significantly more likely to develop malignant tumors. This detailed study gives insight into the most frequent tumors that occur in cats from Croatia, and the data reported here is likely applicable to other countries. This data will contribute to clinical veterinary oncology, as it presents the most extensive tumor index of cats in south-eastern Europe.

Acute lethal leptospirosis in a red fox (Vulpesvulpes).

Leptospirosis, caused by pathogenic spirochaetes belonging to the genus Leptospira, is a globally distributed zoonosis that can affect many species of domestic and wild animals, and humans. The red fox (Vulpes vulpes) is a native species in Croatia and, due to constant food availability and lack of interspecies competition, is becoming more abundant in urban and suburban areas. Although antibodies for Leptospira spp have been detected in red foxes, lethal disease has not been reported. We necropsied a young, male red fox that had jaundice, multifocal haemorrhages in the heart, lungs and urinary bladder, hepatomegaly, non-congestive splenomegaly and slight yellow discolouration of the renal cortex and medulla. Histology revealed multifocal haemorrhages in parenchymal organs, thrombi within lung septal capillaries and other blood vessels, interstitial lymphocytic and plasmacytic nephritis and erosions of the gastric mucosa. A microscopic agglutination test on the post-mortem cardiac blood clot revealed a high titre to Leptospira interrogans serovar Icterohaemorrhagiae, which implies contact with rats, which are natural reservoirs of this serovar in Croatia. The gross and histological findings in this fox were similar to those in dogs with leptospirosis, indicating that fatal leptospirosis can occur in foxes and suggesting that this species can act as a source of infection for other animals and humans.

Ovarian Suture Granuloma Resembling a Tumor in a Bitch.

Ovariohysterectomy is a common surgical procedure performed on female dogs throughout the world. One rare complication is the development of granulomas as a reaction to sutures. Granulomas can grossly and on diagnostic imaging mimic neoplasia, which can present a diagnostic challenge. We present a rare case of ovarian suture granuloma, which resembled a tumor on diagnostic imaging. A 5-year-old, spayed, mixed-breed bitch was presented for anorexia and apathy lasting for a week. On clinical examination fever, dehydration, enlarged lymph nodes, and a tense abdomen were evident. Radiology and ultrasound revealed a 9 cm x 7 cm mass at the location of the left ovary, presumed to be a tumor. The mass was removed on laparotomy and submitted for histopathology which diagnosed granulomatous inflammation as a reaction to a foreign body (most consistently with suture reaction). The current case presents a rare late complication of ovariohysterectomy in the form of a suture granuloma. The case emphasizes the need for additional diagnostic procedures for etiologic diagnosis of masses encountered in the abdomen, especially histopathology, as diagnostic imaging cannot distinguish inflammation from neoplasia.

Pyometra Associated With Staphylococcus Pseudintermedius in Two Bitches.

Staphylococcus pseudintermedius is a commensal bacterium residing on the mucosae and skin surfaces of dogs. Under favorable conditions, the organism may cause serious infections, primarily involving the skin, but it is also isolated in eye and ear infections. This report describes pathologic findings of pyometra associated with S pseudintermedius in two bitches. One bitch was a 6-year-old Pomeranian bitch who died after three days of diarrhea, vomiting, and depression. During necropsy, the uterus of the bitch was diffusely enlarged and filled with 30 mL of thick, yellow, creamy pus. Histology revealed acute to subacute, diffuse, severe, purulent endometritis with intralesional Gram-positive round cocci revealed as S pseudintermedius. The cause of death was pyometra with subsequent septic shock. The other bitch was a 2-year-old West Highland White Terrier who underwent diagnostic laparotomy due to suppurative peritonitis of unknown cause. During the procedure, about 100 mL of yellow, opaque exudate from the abdominal cavity was removed. The distended uterine horns noted during the procedure were removed and submitted for histopathology which revealed necrosis of endometrium with the accumulation of pus and numerous, intralesional S pseudintermedius in the uterine lumen. Focally, uterine wall necrosis was evident, with a spread of bacteria and purulent inflammation into the adjacent mesometrium causing purulent peritonitis. Although S pseudintermedius presents a common cause of skin and mucosal infection, it should be considered a possible etiological agent of canine pyometra.

Endometrial Mucinous Adenocarcinoma in a Bitch With Pyometra-A Case Report.

Endometrial adenocarcinomas present rare neoplasia of bitches. This case report describes mucinous endometrial adenocarcinoma in a bitch with concurrent pyometra for the first time. A mass on the uterine stump was removed during surgery of a 13-year-old bitch with clinically suspected pyometra. Histopathology revealed mucinous endometrial adenocarcinoma. The tumor was classified according to human classification, responding to women's type I (endometrioid carcinoma). Immunohistochemistry showed a positive expression of estrogen receptor α, progesterone receptor, p53, and p16 gene, while vimentin was not expressed.

Retrospective study of canine infectious haemolytic anaemia cases reveals the importance of molecular investigation in accurate postmortal diagnostic protocols.

Infectious haemolytic anaemia (IHA) in dogs share similar clinical signs including fever, lethargy, icterus, paleness of mucous membranes and splenomegaly. Postmortal findings are similar and, without additional diagnostic methods, an accurate aetiological diagnosis is difficult to achieve. In order to investigate causes of lethal IHA in Croatian dogs, we performed a retrospective study on archived formalin-fixed, paraffin-embedded tissue blocks (FFPEB) from dogs that died due to haemolytic crisis, using microscopic and molecular diagnostic tools to determine the aetiological cause of disease. Molecular analysis was performed on kidney, lung, myocardium and spleen on FFPEB from all dogs. The originally stated aetiological diagnosis of B. canis or leptospirosis was confirmed in only 53% of the dogs. PCR and sequencing revealed that, in addition to the expected pathogens, B. canis and Leptospira interrogans, the presence of previously undiagnosed "new" pathogens causing anaemia including Candidatus Neoehrlichia mikurensis and Anaplasma phagocytophilum. Furthermore, Theileria capreoli was detected for the first time in a dog with postmortal descriptions of lesions. Intensive extravascular hemolysis was noticeable as jaundice of the mucosa, subcutis and fat tissue, green or yellow discoloration of renal parenchyma caused by bilirubin excretion in the renal tubules and bile accumulation within the liver in 90% of the dogs. This work highlights the value of molecular diagnostics to complement traditional ante-mortem and post-mortem diagnostic protocols for the aetiological diagnosis of pathogens associated with IHA.

Seroprevalence of vector-borne pathogens in dogs from Croatia.

Canine vector-borne pathogens (VBPs) are a group of globally distributed and rapidly spreading microorganisms transmitted by arthropods. In the present survey, we investigated Anaplasma spp., Ehrlichia canis, Dirofilaria immitis and Borrelia burgdorferi sensu lato seroprevalence between three groups of dogs (asymptomatic, suspected and deceased) from continental and coastal regions of Croatia with the commercial point-of-care SNAP®4Dx®Plus for VBPs. The overall prevalence for tested pathogens in dogs was 6.1% with the highest prevalence detected for Anaplasma spp. (4.5%), while the remaining pathogens were found at a prevalence of less than 1% (E. canis 0.6%, B. burgdorferi s.l. 0.4%, D. immitis 0.6%). No statistically significant differences in VBP detection between dog cohorts could be found with the exception of D. immitis in the deceased group. Interestingly, no evidence of D. immitis could be found in the hearts of dogs in this group at necropsy, however. This study provides the first data on the seroprevalence of selected VBPs between dogs of different health statuses in Croatia. The results demonstrate that serological evidence of VBPs alone or in combination with co-infections were found just as frequently in asymptomatic dogs as those with suspected or confirmed evidence of VBP disease, raising questions about the pathogenic potential of these organisms in domesticated dogs.

Hepatozoon martis n. sp. (Adeleorina: Hepatozoidae): Morphological and pathological features of a Hepatozoon species infecting martens (family Mustelidae).

Species of the genus Hepatozoon (Adeleorina: Hepatozoidae) are arthropod-transmitted protozoan parasites that infect a wide range of vertebrate hosts. In the present study, we describe a new species of Hepatozoon primarily infecting martens and propose the name Hepatozoon martis n. sp., based on its unique morphological, molecular and pathogenic features. The overall prevalence of infection with H. martis n. sp. assessed by PCR in European pine martens (Martes martes) from Bosnia and Herzegovina and stone martens (Martes foina) from Croatia was 100% and 64%, respectively. Gamonts were found in neutrophils and monocytes, and various developmental stages were described in tissue cross-sections. Hepatozoon martis n. sp. shows a high predilection for muscle tissue, and the heart was the most frequently affected organ among the tissues tested by histopathology. Microscopically, pyogranulomatous lesions associated with the presence of the parasitic forms were observed in the cardiac and skeletal muscles of all positive animals examined. Furthermore, the possible existence of alternative, non-vectorial routes of transmission is discussed.

Microscopic and molecular analysis of Babesia canis in archived and diagnostic specimens reveal the impact of anti-parasitic treatment and postmortem changes on pathogen detection.

BACKGROUND: Classification of Babesia parasites has traditionally relied on morphological differentiation based on piroplasm size and shape. Molecular typing has subsequently revealed a more complex taxonomy for these piroplasms than previously thought. To evaluate the factors that influence the morphology of Babesia species upon microscopic examination and hence, their taxonomic classification, we performed detailed characterizations of piroplasms from archival and prospective collections of cytological samples of dogs with piroplasmosis before and after death. Merozoite morphology and time of parasite disappearance following imidocarb dipropionate was also investigated. METHODS: The study was divided into a (i) review of archived cytological slides from confirmed cases of canine piroplasmosis, and (ii) a prospective study of smears and tissue imprints from 15 recently necropsied dogs. The latter group could be further sub-divided into a non-treated group and an imidocarb dipropionate-treated group. Exact times of treatment before death were reviewed. Additional blood smears prepared from the live dogs and taken before therapy were also evaluated in the latter group. Parasite burden per each slide was determined in both studies. The shape and size of merozoites were described from blood smears taken while the dogs were alive and from different organs during necropsy. The results of all measurements were statistically analyzed. RESULTS: The morphology and size of merozoites from live dogs corresponded to that of previously described 'large' Babesia. The morphology and size of merozoites were significantly different (P < 0.001) in postmortem samples, however, and more consistent in shape and size with piroplasm cells previously referred to as 'small' Babesia. PCR and sequencing confirmed B. canis as the causative agent of disease in all investigated dogs, including in postmortem negative tissue imprints from dogs treated at least 24 h before death. CONCLUSIONS: Changes in the morphology of 'large' B. canis to 'small'-like Babesia observed by light microscopy appear to represent a common postmortem change. Classification of Babesia parasites into 'large' and 'small' Babesia using only microscopy of postmortem slides should be treated with caution. PCR-based methodologies for detection and molecular typing of Babesia spp. may prove valuable for investigating suspected cases of babesiosis following necropsy.

Molecular detection of Anaplasma platys, Anaplasma phagocytophilum and Wolbachia sp. but not Ehrlichia canis in Croatian dogs.

The bacteria Anaplasma platys, Anaplasma phagocytophilum and Ehrlichia canis are tick-borne agents that cause canine vector-borne disease. The prevalence of these pathogens in South Eastern Europe is unknown with the exception of an isolated case of A. platys detected in a dog imported into Germany from Croatia. To gain a better insight into their presence and prevalence, PCR-based screening for these bacterial pathogens was performed on domesticated dogs from different regions of Croatia. Blood samples from 1080 apparently healthy dogs from coastal and continental parts of Croatia as well as tissue samples collected from 63 deceased dogs with a history of anaemia and thrombocytopenia were collected for molecular screening by an Anaplasmataceae-specific 16S rRNA conventional PCR. Positive samples were confirmed using a second Anaplasmataceae-specific PCR assay with the PCR product sequenced for the purpose of bacterial species identification. All sequenced isolates were georeferenced and a kernel intensity estimator was used to identify clusters of greater case intensity. 42/1080 (3.8%; CI 2.7-5.0) of the healthy dogs were PCR positive for bacteria in the Anaplasmataceae. Sequencing of the 16S rRNA gene amplified from these positive samples revealed the presence of A. platys in 2.5% (CI 1.6-3.4%, 27 dogs), A. phagocytophilum in 0.3% (CI 0-0.6%, 3 dogs) and a Wolbachia endosymbiont in 1.1% (CI 0.4-1.6%, 12 dogs) of dogs screened in this study. Necropsied dogs were free from infection. Notably, no evidence of E. canis infection was found in any animal. This survey represents a rare molecular study of Anaplasmataceae in dogs in South Eastern Europe, confirming the presence of A. platys and A. phagocytophilum but not E. canis. The absence of E. canis was surprising given it has been described in all other Mediterranean countries surveyed and raises questions over the regional vector capacity of the Rhipicephalus sanguineus tick.

The prevalence and impact of Babesia canis and Theileria sp. in free-ranging grey wolf (Canis lupus) populations in Croatia.

BACKGROUND: Babesia spp. and Theileria spp. are important emerging causes of disease in dogs. Alongside these domesticated hosts, there is increasing recognition that these piroplasms can also be found in a range of wild animals with isolated reports describing the presence of these pathogen in foxes (Vulpes vulpes) and captive grey wolves (Canis lupus). The prevalence and impact of these infections in free-ranging populations of canids are unknown. To gain a better insight into the epidemiology and pathogenesis of piroplasm infections in free-ranging grey wolves, pathological and molecular investigations into captive and free-ranging grey wolves in Croatia were performed. RESULTS: The carcasses of 107 free-ranging wolves and one captive wolf were the subjects of post-mortem investigations and sampling for molecular studies. A blood sample from one live captured wolf for telemetric tracking was also used for molecular analysis. PCR amplification targeting the 18S RNA gene revealed that 21 of 108 free-ranging wolves and one captive animal were positive for Theileria/Babesia DNA. Subsequent sequencing of a fragment of the 18S RNA gene revealed that 7/22 animals were positive for Babesia canis while the other amplified sequence were found to be identical with corresponding 18S rDNA sequences of Theileria capreoli isolated from wild deer (15/22). Haematological and cytological analysis revealed the presence of signet-ring shaped or pear-shaped piroplasms in several animals with the overall parasite burden in all positive animals assessed to be very low. Pathological investigation of the captive animal revealed fatal septicemia as a likely outcome of hemolytic anaemia. There was little or no evidence of hemolytic disease consistent with babesiosis in other animals. CONCLUSION: Importantly, the presence of B. canis in free-ranging grey wolves has not been described before but has been reported in a single fox and domestic dogs only. That B. canis infections cause disease in dogs but have little impact on wolf health possibly suggests that the wolf is the natural and the domestic dog is a secondary host. Surprisingly, the frequent finding of Theileria capreoli in wolves suggests that this Theileria species is not restricted to ungulates (cervids) but commonly infects also this carnivore species. Nevertheless, the potential role that these asymptomatically infected animals may play in the dispersal of these pathogens to susceptible sympatric species such as domesticated dogs requires further investigation.