Seroprevalence of Streptococcus equi subspecies equi in Croatia - Short communication.

Clinical cases resembling strangles are regularly seen in some areas of Croatia. However, there are no data on the prevalence of infection and the clinical forms or geographic distribution of the disease. The aim of this study was to determine the seroprevalence of Streptococcus equi subspecies equi in horses resident in Croatia, in order to estimate the geographic distribution of infection. The study included 291 horse sera from the eight counties where the majority of Croatian horses are kept. Sera were tested by indirect ELISA (iELISA) for the presence of serum antibodies against S. equi protein A (SEQ_2190) and protein C (SeM). Positive horses were detected in all counties. Overall seroprevalence was 16.5 per cent (48/291), ranging from 7.1 to 29.6 per cent. A positive association was observed between the population size of the horses in the counties and the seropositivity rates: the larger the population, the higher the seropositivity. The results of this study suggest that S. equi infection is widespread in Croatia. Further investigation of the clinical manifestations, circulating strains and other characteristics of the disease in Croatia and raising awareness of the disease among horse owners are now required.

Phylogenetic characterisation of feline immunodeficiency virus in naturally infected cats in Croatia indicates additional heterogeneity of subtype B in Europe.

This study was performed on 29 domestic cats with a variety of clinical signs, possibly related to FIV infection. Blood samples were tested by a rapid immunochromatographic (ICA) procedure for detection of FIV antibodies. Subsequently, polymerase chain reaction (PCR) was performed to amplify a portion of the proviral gag gene. All 11 positive PCR products were sequenced and compared with previously reported FIV sequences. Croatian proviral isolates that could be amplified were clustered within subtype B, and additional heterogeneity was confirmed by the formation of three separate clusters. Phylogenetic analysis of circulating strains in Croatia and in southeast Europe is necessary to improve diagnostic methods and selection of the appropriate vaccinal strains.

Association between Exposure to Leptospira spp. and Abortion in Mares in Croatia.

Leptospirosis is one of the most common zoonotic infections and a major problem in terms of both veterinary medicine and public health. However, the disease is under-recognised and under-diagnosed worldwide, particularly in horses. Clinical leptospirosis in horses is mainly associated with recurrent uveitis (ERU), which has recently been studied more intensively, and reproductive disorders, the epidemiology of which is still relatively poorly understood. To enhance our comprehension of abortions caused by leptospirosis in horses and to identify the causative strains, a serological study was carried out with subsequent molecular characterisation of the isolate obtained. Using the microscopic agglutination test (MAT), serum samples from mares that aborted and foetal fluids (when available) were tested for antibodies against Leptospira spp. Furthermore, bacteria isolation from kidney cultures was conducted. Of 97 mare serum samples, 21 (21.64%) tested positive, with Grippotyphosa and Pomona being the most frequently detected serogroups. A significantly higher seroprevalence was found in aborting mares compared to the healthy horse population from the same geographical area, as well as a pronounced seasonal variation. Leptospiral antibodies were not detected in any of the foetal fluids, but isolation was successful in 1 case out of 39 (2.56%). Genotyping by multilocus sequence typing (MLST) and core genome multilocus sequence typing (cgMLST) identified the obtained isolate as Leptospira kirschneri, serogroup Pomona, serovar Mozdok. Further surveillance and molecular typing of Leptospira strains causing abortion in horses would be invaluable in understanding the prevalence and impact of leptospirosis on equine reproductive health in Europe.

Serological Surveillance of Equine Leptospirosis in Croatia in the Period From 2012 to 2022: A Key Insight Into the Changing Epizootiology.

Leptospirosis is re-emerging zoonotic bacterial disease of global importance that affects domestic and wild animals and humans. Due to the public health importance, control of disease in Croatia is being implemented by monitoring the seroprevalence of equine leptospirosis and it is regulated by the law. In the period from 2012 to 2022, a total of 61,724 serum samples from apparently healthy horses were admitted to the Laboratory for leptospires, Faculty of Veterinary Medicine University of Zagreb. Serum samples were tested for Leptospira spp. antibodies using the microscopic agglutination test (MAT). Samples were considered seropositive with a cut-off titre 1:200 for Bratislava and 1:400 for other Leptospira spp. serovars. Out of 61,724 serum samples tested, 6,665 (10.80%) were found seropositive for at least one Leptospira serovar. In the studied period, seroprevalence varied between 5.00% and 15.94%. The highest seroprevalence was found for serovar Pomona (41.98%) and serovar Grippotyphosa (31.34%), followed by Sejroe (8.03%), Icterohaemorrhagiae (7.05%) and Bratislava (6.47%). Results indicated that horses in Croatia are particularly exposed to Leptospira spp. infections. The most prevalent presumed infective serovar was Pomona increasing each year. Investigated horses were randomly selected and healthy and most seropositive horses have anamnestic titre due to previous infection. This is the first study in Europe reporting such high seropositivity for the serovar Pomona in apparently healthy horses. According to the results of the present study, the question arises of the possible evolutionary adaptation of the pathogenic serovar Pomona as dominant for horses.

The Emergence of SARS-CoV-2 within the Dog Population in Croatia: Host Factors and Clinical Outcome.

Over a year into the COVID-19 pandemic, there is growing evidence that SARS-CoV-2 infections among dogs are more common than previously thought. In this study, the prevalence of SARS-CoV-2 antibodies was investigated in two dog populations. The first group was comprised of 1069 dogs admitted to the Veterinary Teaching Hospital for any given reason. The second group included dogs that shared households with confirmed COVID-19 cases in humans. This study group numbered 78 dogs. In COVID-19 infected households, 43.9% tested ELISA positive, and neutralising antibodies were detected in 25.64% of dogs. Those data are comparable with the secondary attack rate in the human population. With 14.69% of dogs in the general population testing ELISA positive, there was a surge of SARS-CoV-2 infections within the dog population amid the second wave of the pandemic. Noticeably seroprevalence of SARS-CoV-2 in the dog and the human population did not differ at the end of the study period. Male sex, breed and age were identified as significant risk factors. This study gives strong evidence that while acute dog infections are mostly asymptomatic, they can pose a significant risk to dog health. Due to the retrospective nature of this study, samples for viral isolation and PCR were unavailable. Still, seropositive dogs had a 1.97 times greater risk for developing central nervous symptoms.

New trends in human and animal leptospirosis in Croatia, 2009-2014.

Leptospirosis is a geographically widespread and globally underestimated zoonosis that affects humans and variety of animals. To identify trends and possible risk factors, joined medical and veterinary teams investigated epidemiology and epizootiology of leptospirosis in Croatia. Retrospective analysis of data obtained from referent diagnostic laboratories included a total of 1917 human and 123964 animal sera tested in the period from 2009 to 2014. We found high human leptospirosis average incidence rate of 1.53/100000 with clear predominance of male patients older than 40 years (sex ratio M/F:3.2; median age 51±15.1years). Statistical analysis revealed seasonal and annual variations of incidence in humans that were primarily associated with favourable weather conditions (temperature 10-19, 9°C and precipitation above 100mm/m2). Majority of infections in humans were caused by serogroups Sejroe, Australis and Icterohaemorrhagiae. Notable variations in seroprevalence and changing trends in prevailing serogroups were recorded in most of the domestic animals and during the entire period of investigation. All of the observed findings underline leptospirosis as a significant human and veterinary public health threat and emphasize the importance of continuous multidisciplinary surveillance. We also argue that only input from both professions improves our overall knowledge on leptospirosis and leads to better and more efficient prevention and control strategies.