First Insight into the Seroepidemiology of Hepatitis E Virus (HEV) in Dogs, Cats, Horses, Cattle, Sheep, and Goats from Bulgaria

In recent years, hepatitis E virus (HEV) infection has been found to be widespread among different animal species worldwide. In Bulgaria, high HEV seropositivity was found among pigs (60.3%), wild boars (40.8%), and East Balkan swine (82.5%). The aim of the present study was to establish the seroprevalence of HEV among dogs, cats, horses, cattle, sheep, and goats in Bulgaria. In total, 720 serum samples from six animal species were randomly collected: dogs-90 samples; cats-90; horses-180; cattle-180; sheep-90; and goats-90. The serum samples were collected from seven districts of the country: Burgas, Kardzhali, Pazardzhik, Plovdiv, Sliven, Smolyan, and Stara Zagora. The animal serum samples were tested for HEV antibodies using the commercial Wantai HEV-Ab ELISA kit (Beijing, China). The overall HEV seroprevalence among different animal species from Bulgaria was as follows: dogs-21.1%; cats-17.7%; horses-8.3%; cattle-7.7%; sheep-32.2%; and goats-24.4%. We found the lowest overall HEV seropositivity in Plovdiv district (6.2%; 4/64; p = 0.203) and Smolyan district (8.8%; 4/45; p = 0.129), vs. the highest in Pazardzhik district (21.6%; 29/134; p = 0.024) and Burgas district (28.8%; 26/90; p = 0.062). To the best of our knowledge, this is the first serological evidence of HEV infection in dogs, cats, horses, cattle, sheep, and goats from Bulgaria. We found high HEV seropositivity in small ruminants (sheep and goats), moderate seropositivity in pets (dogs and cats), and a low level of seropositivity in large animals (horses and cattle). Previous Bulgarian studies and the results of this research show that HEV infection is widespread among animals in our country. In this regard, the Bulgarian health authorities must carry out increased surveillance and control of HEV infection among animals in Bulgaria.

Serological Searching for Hepatitis E Virus Infection Among Pig Liver Transudate from Bulgaria: An Alternative Method for Seroepidemiological Survey

Background: The aim of this research was to perform a seroepidemiological survey of hepatitis E virus (HEV) by an alternative method-serological establishment of the virus from pig liver transudate. This is the first such research in Bulgaria. Moreover, no studies have been conducted on HEV in pig liver in our country. Materials and Methods: A total of 90 liver samples from healthy pigs were collected from slaughterhouses in three parts of the country (Sofia, Lovech, and Stara Zagora districts). An equal number of samples (n = 30) were obtained from each district. Results: The overall HEV seropositivity was 67.7% of all 90 tested pig liver transudate samples; in Sofia district 20.0%, in Lovech district 90.0%, and in Stara Zagora district 93.3%. Conclusion: These data are similar to our previous serological studies for HEV in serum samples from industrial pigs, wild boars, and East Balkan swine. In this regard, testing the liver transudate could be a fine alternative method for seroepidemiological survey on HEV in swine.

Seroprevalence of Actinobacillus pleuropneumoniae infection in pigs from Bulgaria

Actinobacillus pleuropneumoniae (App) is the etiological agent of porcine pleuropneumonia. The purpose of the study was to present a serological report on App prevalence among pigs in industrial farms in Bulgaria. Seventy-two pigs from four industrial farms in four districts of Bulgaria – Eastern Bulgaria (Razgrad and Yambol districts) and Western Bulgaria (Lovech and Sofia districts) were included. Animals were divided in two age groups: weaners and fattening pigs. A commercial enzyme-linked immunosorbent assay (ELISA, INgezim APP MIX, Eurofins Ingenasa, Madrid, Spain) for the detection of antibodies against App parasuis in porcine serum was used. Microtitrе plate was coated with App antigen of the serovars 1, 2, 9 and 11. Positive results for anti-App antibodies were detected in 32 (44.4%) of all 72 tested sera. The overall seropositivity in weaners and fattening pigs was 22.2% (8/36), and 66.7% (24/36), respectively. The highest App seropositivity in pigs was found in Eastern Bulgaria - 61.1% (22/36; P<0.001) in comparison to App seropositivity in Western Bulgaria – 27.8% (10/36; P=0.137). This study on anti-App prevalence among pigs in Bulgaria gives new insights on App epidemiology in our country.

A Molecular Study on Hepatitis E Virus (HEV) in Pigs in Bulgaria

Information on hepatitis E virus (HEV) strains circulating in animal reservoirs in Bulgaria is currently lacking. Herein, by screening HEV seropositive sera obtained from Bulgarian swine and wild boars, viral RNA was detected at high prevalence rate (28.2%) in industrial pigs. Sequence analysis of the partial polymerase (RdRp) region revealed the highest genetic correlation with HEVs of genotype (Gt) 3 identified in French and Dutch patients. For three such strains, a 700-bp fragment of the open reading frame 2 gene was generated. On phylogenetic analysis, the Bulgarian strains clustered tightly (93.8-98.3% nt) with human and animal HEVs classified within the Gt3 subtype c.

Serological evidence of hepatitis E virus infection in pigs from Northern Bulgaria

The purpose of the present study was to investigate pigs in Northern Bulgaria for serological evidence of hepatitis E virus (HEV). Sera from 225 individuals from three industrial farms were tested for anti‑HEV IgG antibodies. The overall HEV seroprevalence was 36% (81/225); weaners 6.8% (5/74); fattening pigs 38.7% (29/75) and in sows 61.8% (47/76). Compared to weaners, HEV positivity was higher in fattening pigs and sows: OR = 8.70 (95% CI: 3.14‑24.12) and OR = 22.37 (95% CI: 8.07‑61.96), respectively. These data confirm that HEV is endemic in pigs throughout Bulgaria, and can be a Public Health problem due to the transmission of HЕV to humans through the consumption of pork meat and pork products.

Seroprevalence of Hepatitis E Virus Infection Among Wild Boars in Western Bulgaria

Scientific evidence indicates that hepatitis E virus (HEV) infection is a zoonotic disease. Domestic pigs and wild boars are the main animal reservoir for HEV worldwide. The aim of this study was to analyze the seroprevalence of HEV infection among wild boars in western Bulgaria. Serum samples from 240 wild boars from two regions of the country (northwestern and southwestern) were tested for anti-HEV Immunoglobulin G (IgG) antibodies. The overall HEV seroprevalence was 40.8% (98/240); northwestern region 40.0% (48/120); southwestern region 41.7% (50/120). HEV seropositivity in the southwestern region was higher than in the northwestern region: odds ratio = 1.071 (95% confidence interval: 0.640-1.793). This research provided the first seroprevalence study to HEV in wild boars from western Bulgaria.

High Seroprevalence of Hepatitis E Virus Infection Among East Balkan Swine (Sus scrofa) in Bulgaria: Preliminary Results

The East Balkan swine (Sus scrofa) is the only aboriginal pig breed in Bulgaria, and it is indigenous to the eastern part of the country. The aim of the present study was to investigate East Balkan swine (EBS) in Bulgaria for serological evidence of hepatitis E virus (HEV). Sera from 171 swine from two parts of the country (northeastern and southeastern) were tested for anti-HEV IgG antibodies. The overall HEV seroprevalence was 82.5% (141/171), and for weaners it was 77.2% (44/57), for fattening pigs 79.0% (45/57), and for adults 91.2% (52/57). HEV positivity was higher in fattening pigs and adults compared to weaners: OR = 1.108 (95% CI: 0.456–2.692) and OR = 3.073 (95% CI: 1.016–9.294), respectively. This study provides the first evidence of exposure to HEV in EBS from Bulgaria.

STUDY ON THE EFFECTIVENESS OF INTRACISTERNAL ANTIBIOTIC TREATMENT FOR THE CONTROL OF MASTITIS IN GOATS

The aim of this study is to investigate the healing and prophylactic effect of drying-off antibiotic therapy using the selective and non-selective approach of administration of the antibiotics. First experimental group at the start of the dry period were treated non-selectively (all halves) intra-cisternally with antibiotics. In the second group, we only treated those halves that were diagnosed with subclinical mastitis. The control group of 9 goats was not treated. The number of somatic cells in treated groups after birth decreased from 2586 x 10³/ mL to 560 x 10³/mL in the first group and from 1978 x 10³/mL to 526 x 10³/mL in the second. Post partum, 10% of the halves were found to have subclinical mastitis. A healing effect was achieved in 25% (n=5) milk halves. New intramammary infections developed during the dry period also occurred in 5% (n=1) of the milk halves. In the second post-partum study, subclinical mastitis was observed only in 5% (n=1). Healing was achieved in 30% (n = 6) and the new intramammary infections (NIMIs) were 10% (n=2). In the control group, healing was only observed in 5% (n=1) and NIMI were 27.78% (n=5). The application of both treatment approaches, results in reduction in prevalence and manifestation of mastitis, as well as reduction of somatic cells in milk after kidding. The selective treatment method may be preferred, in order to reduce the cost of medications in conducting treatment and prophylaxis programs.

Seroprevalence of Hepatitis E Virus Infection in Pigs from Southern Bulgaria

Hepatitis E virus (HEV) has been isolated from humans and several animals' species. During the last years, the knowledge of HEV infection dramatically changed and enriched. The aim of this study was to estimate the seroprevalence of HEV in industrial pigs in different districts of Southern Bulgaria. Three hundred sixty swine serum samples were tested for anti-HEV IgG antibodies. The samples were collected from four industrial farms from three districts of Southern Bulgaria. HEV-specific antibodies in porcine serum were detected by enzyme-linked immunosorbent assay (PrioCHECK HEV Ab porcine). The overall HEV seroprevalence was 60.3%. The seropositivity varied widely depending on age groups and investigated farms. The overall prevalence in weaners was 25%, in fattening pigs 75.8%, and in group of sows was found the highest HEV positivity of 80%. The occurrence of HEV positivity in sows and fattening pigs presented odds ratio (OR) = 17.200 (95% confidence interval [CI]: 8.8-33.7) and OR = 11.342 (95% CI: 6.1-21.0), respectively, compared to weaners. The study indicated that HEV is widespread in industrial farms in Bulgaria and presented high seroprevalence in pigs. The results found that HEV seropositivity showed age dependency. The National Health Authorities should raise awareness of HEV and its zoonotic potential.

Hepatitis E Virus Infection in Bulgaria: A Brief Analysis of the Situation in the Country

BACKGROUND:

Over the past two decades, more thorough investigations for hepatitis E virus (HEV) infection have been done in the world. Reports from Southeast European countries have increased.

AIM:

The current article presents a critical analysis of all studies for HEV in Bulgaria.

MATERIAL AND METHODS:

A literature search was done using available medical databases. We analysed the literature in PubMed databases and Bulgarian medical databases for English and Bulgarian languages sources. Preference was given to the sources published within the past 24 years (January 1995 – September 2018).

RESULTS:

Two thousand two hundred and fifty-seven blood serums were tested for the analysed period (1995 – 2018), and 13.1% of them were positive for acute HEV (Mean ± SD: 20.38 ± 25.77%; 95% CI: 1.29 – 39.47%). The following subtypes were established in the country – HEV Subtype 3e, HEV Subtype 3f, HEV Subtype 3c, HEV Subtype 3i, HEV Subtype 3hi and HEV Subtype 1.

CONCLUSION:

We hope that the National Health Organizations will take adequate and timely measures to increase the knowledge and research for HEV among Bulgarian citizens.

Clinical Testing of Combined Vaccine Against Enzootic Pneumonia in Industrial Pig Farming in Bulgaria

In the pig farm with signs of a respiratory disease complex and laboratory confirmed enzootic pneumonia, the prophylactic efficacy of the combination vaccine (M. hyo+PCV2), a single injection administered intramuscularly 21 days after birth, at a dose of 2 ml was tested. The clinical condition, pathological changes in the lungs and some epidemiological and economic results were reported. It was found that vaccinated pigs are in a better clinical condition in comparison with the control group. Morbidity in the rearing period was reduced from 16.3% in the control group to 6.0% in vaccinated pigs, and in the fattening period, respectively, from 30.6% in the control group to 10.0% in the vaccinated group. Pathological features in the lung characteristic for the enzootic pneumonia in the vaccinated pigs were reduced from 25.5%±7.24 to 4.0%±2.44, and PCVI - from 13.0%±4.66 to 0%. Vaccination of pigs has been received and a higher average daily gain in groups for rearing (0.624 kg) and for fattening (0.723 kg) was recorded.