Acta Veterinaria Hungarica 53 (2) (2005)

CONTENTS AND ABSTRACTS

Animal breeding

Measurement of belly composition variability in pigs by in vivo computed tomographic scanning. R. Romvári, A. Szabó, J. Kárpáti, G. Kovach, G. Bázár and P. Horn 153

Bacteriology

Development of a pcr system for the characterisation of Salmonella flagellin genes. A. Imre, F. Olasz and B. Nagy 163

Immunology

Oesophageal tonsil of the chicken. N. Nagy, B. Igyártó, A. Magyar, Emese Gazdag, V. Palya and I. Oláh 173

Mycotoxin research

Novel strategies to control mycotoxins in feeds: A review. J. Varga and Beáta Tóth    189

Parasitology

Ultrastructural observations on the surface of Thelazia lacrymalis (Nematoda: Spirurida, Thelaziidae). Soraya Naem 205

Pathology

Haemorrhagic nephritis and enteritis of geese: Pathomorphological investigations and proposed pathogenesis. M. Dobos-Kovács, E. Horváth, A. Farsang, Edith Nagy, Andrea Kovács, F. Szalai and S. Bernáth 213

Osteoclast-like giant cell tumour arising from the kidney in a dog. R. Haziroglu, O. Kul, R. Tunca and T. Guvenc 225

Pharmacology

Pharmacokinetics and renal toxicity of three once-a-day doses of amikacin in cows. H. Sumano, Lilia Gutierrez, C. Velazquez and Sayuri Hayashida 231

Reproduction

Effect of the in vitro maturation medium on equine oocytes: Comparison of follicular fluid and oestrous mare serum. Lydia Gil, S. Saura, Arantxa Echegaray, Felisa Martinez, I. de Blas, A. Akourki, Noelia Gonzalez, E. Espinosa and A. Josa 241

Use of aglepristone and aglepristone + intrauterine antibiotic for the treatment of pyometra in bitches. K. Gürbulak, Ş. M. Pancarci, H. Ekici, C. Konuk, I. Kirşan and M. Uçmak 249

A modified surgical technique for repairing third-degree perineal lacerations in mares. G. Kaşikçi, Huriye Horoz (Kaya), S. Alkan, O. Düzgün and M. Aktaş 257

Virology

Detection of bovine herpesvirus 4 in cd11b+ leukocytes of experimentally infected rabbits. Katalin Fábián, Rita Ivanics, Melinda Terényi and L. Egyed 265

Acta Veterinaria Hungarica 53 (2), pp. 153–162 (2005)

MEASUREMENT OF BELLY COMPOSITION VARIABILITY IN PIGS BY IN VIVO COMPUTED TOMOGRAPHIC SCANNING

R. Romvári1*, A. Szabó1, J. Kárpáti2, G. Kovách1, G. Bázár1 and P. Horn1

1Faculty of Animal Science, Kaposvár University, H-7400 Kaposvár, Guba Sándor u. 40, Hungary; 2ISV Meat Production and Organising Company, Budapest, Hungary

(Received June 29, 2004; accepted December 16, 2004)

The belly region composition of a representative commercial pig sample of 130 castrates was examined by in vivo spiral computed tomographic (CT) scanning. The lean meat percentage, the muscle/fat tissue ratio within the total body and separately within the bacon part were estimated by image analysis. The lean meat content of the total body was determined by the EU reference method. A correlation of r = 0.97 was found between lean meat content of the total body determined by CT estimation and the slaughtering results. The pigs were divided into seven groups on the basis of their lean meat content. The muscle percentage of the bacon part was 26% and 67%, respectively, in the two groups representing the two extremes of lean meat percentage (36% and 67%, respectively). The total volume of the bacon part was relatively constant (8.6 ± 1 dm3) in the groups representing different lean meat categories. At the same time, the fat tissue volume of the bacon part was considerably higher while its muscle tissue volume was markedly lower in the group of the lowest than in that of the highest lean meat content (6.6 vs. 2.5 dm3 and 2.4 vs. 5.5 dm3, respectively). To describe changes in the tissue composition of the bacon part during fattening, 10 castrates were scanned repeatedly at 70, 90 and 110 kg of liveweight. A linear regression model was developed to characterise the continuous decrease observed in the muscle/fat ratio within the bacon part due to increasing liveweight.

Key words: Pig, belly composition, computed tomography, selection

*Corresponding author: Róbert Romvári; E-mail: romvari.robert@freemail.hu; Fax: +36 (82) 320 175

Acta Veterinaria Hungarica 53 (2), pp. 163–172 (2005)

DEVELOPMENT OF A PCR SYSTEM FOR THE CHARACTERISATION OF SALMONELLA FLAGELLIN GENES

A. Imre1, F. Olasz2 and B. Nagy1*

1Veterinary Medical Research Institute of the Hungarian Academy of Sciences, H-1581 Budapest, P.O. Box 18, Hungary; 2Agricultural Biotechnology Center, Gödöllő, Hungary

(Received July 22, 2004; accepted December 16, 2004)

Analysis of flagellin genes was carried out on strains of Salmonella Typhimurium, Salmonella Hadar, Salmonella Abortusequi, Salmonella Enteritidis and Salmonella Gallinarum serovars, using a PCR system designed in this study. The purpose of these studies was to explore the flagellin genes of biphasic and monophasic Salmonellae for future targeted genetic interventions. The PCR primers were designed for two different structural genes of flagellin (fliC, fljB), for the repressor of fliC (fljA), for the operator region of fliC, and for the invertase system responsible for phase variation in Salmonella (hin, hixL, hixR). PCR analysis revealed that all of the examined genes (fliC, fliC-operator, fljB, fljA, hin, hixL, hixR) were present in all S. Typhimurium (n = 10) and S. Hadar (n = 10) strains tested. The results obtained on S. Typhimurium and S. Hadar strains confirmed their biphasic character at DNA level. However, the S. Enteritidis (n = 46) and S. Gallinarum (n = 5) strains lacked the invertase system (hin, hixL, hixR) as well as the fljA and fljB genes, while fliC and its operator were detectable. Consequently, the S. Enteritidis strains could only express fliC gene resulting in phase H1 flagellin. The examined S. Gallinarum strains were also demonstrated to have a cryptic flagellin gene (fliC). On the other hand, PCR results on S. Abortusequi (n = 2) indicated that both flagellin genes (fliC, fljB) and the whole phase variation system were present in both strains tested but only the H2 phase gene (fljB) was expressed. The phenotype of these strains could be clarified by motility test and/or by classical flagellar serology. The findings are also substantiated by the results of serovar-specific PCR for S. Typhimurium and S. Enteritidis. In conclusion, the PCR system developed in this study proved to be suitable for characterisation of Salmonella flagellin genes and confirmed serological results regarding all S. Typhimurium, S. Hadar and S. Enteritidis strains. This system could also identify cryptic flagellar genes of S. Abortusequi and S. Gallinarum.

Key words: Salmonella, PCR, flagellin genes, phase variation

*Corresponding author: Béla Nagy; E-mail: bnagy@vmri.hu; Fax: +36 (1) 252 1069

Acta Veterinaria Hungarica 53 (2), pp. 173–188 (2005)

OESOPHAGEAL TONSIL OF THE CHICKEN

N. Nagy1, B. Igyártó1, A. Magyar1, Emese Gazdag1, V. Palya2 and I. Oláh1*

1Department of Human Morphology and Developmental Biology, Faculty of Medicine, Semmelweis University, H-1094 Budapest, Tűzoltó u. 58, Hungary; 2CEVA-Phylaxia Veterinary Biologicals Co. Ltd., Budapest, Hungary

(Received July 22, 2004; accepted December 16, 2004)

The oesophageal tonsil of the chicken is a novel member of the mucosal-associated lymphoid tissue (MALT), which is located around the entrance of the proventriculus. It consists of 6 to 8 single units, which are surrounded by a thin fibrous capsule. Each one is organised around the bottom of the longitudinal folds of the oesophagus, and serves as a ‘tonsillar crypt’. Stratified squamous epithelium is infiltrated by lymphoid cells, i.e. T cells, plasma cells, macrophages, and dendritic cells, but not B cells, to form lymphoepithelium (LE). In the LE vimentin-, MHC II- and ATPase-positive cells possibly represent Langerhans’ cells, but the appearance of 74.3 positive cells in the LE is unusual, because the 74.3 monoclonal antibody (mAb) recognises chicken follicular dendritic cells in the germinal centre and medulla of the bursal follicles. The subepithelial lymphoid tissue is organised into T- and B-dependent regions, which are the interfollicular areas and the germinal centres, respectively. Existence of high-endothelial venules in the interfollicular region suggests an extensive cellular connection between the oesophageal tonsil and the other lymphoid organs. In the resting oesophagus the lumen is closed, but during swallowing a bolus the crypt opens and the lymphoepithelium can be exposed to undigested food, antigens, infectious agents and vaccines. The location of the oesophageal tonsil, cranial to the stomach, may provide this organ with a unique role as compared to the other parts of the MALT; namely, it may contribute to the replication of infectious bursal disease virus (IBDV) and/or the pathogenesis of infectious bursal disease.

Key words: Gut-associated lymphoid tissue (GALT), chicken, tonsil, lymphoepithelium, dendritic cell

*Corresponding author: Imre Oláh; E-mail: olah@ana2.sote.hu; Phone: +36 (1) 218 2101; Fax: +36 (1) 215 3064. The first two authors contributed equally to this work.

Acta Veterinaria Hungarica 53 (2), pp. 189–203 (2005)

NOVEL STRATEGIES TO CONTROL MYCOTOXINS IN FEEDS: A REVIEW

J. Varga1* and Beáta Tóth2

1Department of Microbiology, Faculty of Sciences, University of Szeged, H-6701 Szeged, P.O. Box 533, Hungary; 2Cereal Research Non-profit Company, Szeged, Hungary

(Received May 4, 2004; accepted September 1, 2004)

Mycotoxin-producing fungi may contaminate agricultural products in the field (preharvest spoilage), during storage (postharvest spoilage), or during processing. Mycotoxin contamination of foods and feeds poses serious health hazard to animals and humans. For lowering mycotoxin contamination of feeds and foods, several strategies have been investigated that can be divided into biological, chemical and physical methods. This paper gives an overview of strategies which are promising with regard to lowering the mycotoxin burden of animals and humans.

Key words: Aflatoxin, fumonisin, mycotoxin, ochratoxin, detoxification, patulin trichothecenes

*Corresponding author: János Varga; E-mail: jvarga@bio.u-szeged.hu; Fax: +36 (62) 544 823

Acta Veterinaria Hungarica 53 (2), pp. 205–212 (2005)

ULTRASTRUCTURAL OBSERVATIONS ON THE SURFACE OF THELAZIA LACRYMALIS (NEMATODA: SPIRURIDA, THELAZIIDAE)

Soraya Naem*

Department of Pathobiology, Faculty of Veterinary Medicine, Urmia University, Nazloo Campus, P.O. Box 1177, Urmia, Iran

(Received September 6, 2004; accepted December 16, 2004)

Scanning electron microscopy (SEM) was used to study the surface ultrastructure of female Thelazia lacrymalis obtained from naturally infected cattle. At the anterior end, the buccal capsule was cup shaped. The mouth was without lips and was surrounded by four cephalic papillae and two amphids. There were two lateral cervical papillae. Also, a single small papilla was seen on the ventral side, close to the vulvar opening. The vulva was located posterior to the end of the oesophagus and the tail carried an anal pore and a pair of phasmids near the tip. The cuticle was transversally annulated with fine striations.

Key words: Morphology, Nematode, Spirurida, Thelaziidae, Thelazia lacrymalis, scanning electron microscopy

*E-mail: sorayanaem@yahoo.com; Fax: +98 (441) 3443442;

This work was carried out at the Department of Pathobiology, Faculty of Veterinary Medicine, Urmia University, Urmia, Iran and the Electron Microscope Facility, Department of Pathology and Molecular Medicine, Faculty of Health Sciences, McMaster University, Hamilton, Ontario, Canada.

Acta Veterinaria Hungarica 53 (2), pp. 213–223 (2005)

HAEMORRHAGIC NEPHRITIS AND ENTERITIS OF GEESE: PATHOMORPHOLOGICAL INVESTIGATIONS AND PROPOSED PATHOGENESIS

M. Dobos-Kovács1, E. Horváth2‡, A. Farsang2, Edith Nagy2, Andrea Kovács2, F. Szalai3 and S. Bernáth2*

1Department of Pathology and Forensic Veterinary Medicine, Faculty of Veterinary Science, Szent István University, Budapest, Hungary; 2Institute for Veterinary Medicinal Products, H-1475 Budapest, P.O. Box 318, Hungary; 3Ceva-Phylaxia Co. Ltd, Budapest, Hungary

(Received November 9, 2004; accepted December 16, 2004)

Haemorrhagic nephritis and enteritis of geese as a new disease was first described in Hungary in 1969. The authors identified the causative agent of the outbreaks occurring in 1969 as a polyomavirus by PCR in 2001. In order to study the pathogenesis of the virus, one-day-old goslings were infected with tissue homogenate that tested positive for polyomavirus by PCR. Morphological, light and transmission electron microscopic (TEM) examinations have revealed that goose haemorrhagic polyomavirus replicates in the endothelial cells of the blood vessels and capillaries of diseased birds. Infection causes damage and necrosis of the endothelial cells. The virus was not observed in the parenchymal cells. Oedema and haemorrhages found throughout the body may be due to the dysfunction or functional deficiency of endothelial cells damaged by the virus.

Key words: Pathogenesis, haemorrhagic enteritis and nephritis of geese, electron microscopy

*Corresponding author: Sándor Bernáth; E-mail: bernath@oai.hu; Fax: +36 (1) 262 2839; ‡Present address: EMEA, 7 Westferry Circus, Canaray Wharf, London, UK

Acta Veterinaria Hungarica 53 (2), pp. 225–230 (2005)

OSTEOCLAST-LIKE GIANT CELL TUMOUR ARISING FROM THE KIDNEY IN A DOG+

R. Haziroglu1*, O. Kul2, R. Tunca3 and T. Guvenc4

1Department of Pathology, Faculty of Veterinary Medicine, University of Ankara, 06110 Diskapi, Ankara, Turkey; 2Kirikkale University, Yahsihan, Kirikkale, Turkey; 3Kafkas University, Kars, Turkey; 419 Mayis University, Samsun, Turkey

(Received August 6, 2004; accepted December 16, 2004)

In this study, a case of osteoclast-like giant cell tumour arising from the kidney is reported in an eight-year-old female Anatolian Shepherd dog. Macroscopically, the tumorous mass covered the hilus of the left kidney. It was 26 × 22 × 12 cm in size and 3700 g in weight. Metastatic tumorous nodules, 0.5–2.0 cm in diameter, were found on the abdominal side of the diaphragm and in the lungs. Microscopically, numerous large osteoclast-like multinucleated giant cells and spindle-spheroidal-shaped cells were seen. Osteoblastic differentiation and osteoid matrix were noted in a few areas at the periphery of the tumour, near the connective tissue septa. The stroma of the tumour tissue was vascular, oedematous and loose. By immunoperoxidase staining, tumour cells showed immunoreactivity for vimentin but not for keratin and desmin, indicating that the tumour had mesenchymal origin. This is the first report in the literature on a malignant osteoclast-like giant cell tumour arising from a visceral organ in animals.

Key words: Dog, giant cell, kidney, osteoclast-like, tumour

*Corresponding author: Rifki Haziroglu; E-mail: hazirogl@veterinary.ankara.edu.tr; Fax: +90 (312) 316 4472

Acta Veterinaria Hungarica 53 (2), pp. 231–240 (2005)

PHARMACOKINETICS AND RENAL TOXICITY OF THREE ONCE-A-DAY DOSES OF AMIKACIN IN COWS

H. Sumano1*, Lilia Gutierrez1, C. Velazquez2 and Sayuri Hayashida1

1Department of Physiology and Pharmacology, School of Veterinary Medicine, National Autonomous University of Mexico, Mexico City 04510, Mexico; 2PARAFARM S.A., Mexico City, Mexico

(Received October 12, 2004; accepted December 16, 2004)

Pharmacokinetic variables of amikacin in cows were determined after administration of amikacin sulphate either intravenously (IV) or intramuscularly (IM) at a dose of 25 mg/kg per day for three days. Amikacin concentrations at time zero and maximum serum concentrations were 240.8 µg/mL and 122.53 µg/mL, respectively. The elimination half-life remained unchanged during the three days of administration (T1ß = 1.33 ± 0.029 h for the IV route and T1ß = 2.75 ± 0.38 h for the IM route). Apparent volumes of distribution suggest limited distribution out of the central compartment (VdAUC = 0.154 ± 0.005 L/kg; Vdc = 36.50 ± 2.35 L; Vdss = 0.092 ± 0.004 L/kg). Bioavailability after IM administration was 95%. Serum profiles of urea, creatinine, albumin, electrolytes and pH after 5-day treatment with amikacin at a dose of 25 mg/kg per day IM revealed no changes. Assessment of diffusion of amikacin to milk by a commercially available screening method to detect antibiotic residues revealed that amikacin could not be detected by the fifth milking period after the last treatment. These results suggest that it would be rational to use a large single-daily dose of amikacin for future clinical trials in cows.

Key words: Amikacin, high dose, renal, toxicity, cows

*Corresponding author: Hector Sumano; E-mail: sumano@servidor.unam.mx; Phone: +525 (56) 22 59 08; Fax: +525 (56) 10 69 92

Acta Veterinaria Hungarica 53 (2), pp. 241–248 (2005)

EFFECT OF THE IN VITRO MATURATION MEDIUM ON EQUINE OOCYTES: COMPARISON OF FOLLICULAR FLUID AND OESTROUS MARE SERUM

Lydia Gil1*, S. Saura1, Arantxa Echegaray2, Felisa Martinez1, I. de Blas1, A. Akourki1, Noelia Gonzalez1, E. Espinosa1 and A. Josa1

1Department of Veterinary Pathology, Faculty of Veterinary Medicine, University of Zaragoza, Spain; 2Empresa Magapor SL, Ejea de los Caballeros, Zaragoza, Spain

(Received January 15, 2004; accepted September 1, 2004)

The present study evaluated the effect of supplementing the medium used to mature equine oocytes in vitro with oestrous mare serum (EMS) or horse follicular fluid (HFF). To this end, 144 ovaries were obtained from mares aged 16–21 months and transported to the laboratory in Dulbecco’s phosphate buffered saline (D-PBS) at 30 °C. Oocytes were harvested from the ovaries by slicing, and then selected for in vitro maturation (IVM) according to the number of cumulus cell layers and the characteristics of the cytoplasm. The selected oocytes were washed three times in TCM199 medium plus HEPES (TCM-199H) or in the same medium plus glutamine (TCM-199G), then matured in vitro in six study groups established according to the in vitro maturation (IVM) treatment to see possible interactions between HEPES and glutamine on other supplements: Ten percent EMS was added to two of these media (TCM-199H+EMS and TCM-199G+EMS) and 10% HFF was added to the media in two other groups (TCM-199H+HFF and TCM-199G+HFF). IVM was performed at 38.5 °C for 40 h in a controlled atmosphere (5% CO2, 95% relative humidity). The findings indicate that the presence of EMS or HFF in the TCM-199H medium gives rise to the best results in terms of the proportions of oocytes reaching maturity (37.7% and 36.8%, respectively). The values obtained with EMS and HFF were statistically similar to each other but differed from the other treatments. The media containing glutamine led to the highest proportions of degenerated oocytes.

Key words: Horse, follicular fluid, oestrous mare serum, glutamine

*Corresponding author: Lydia Gil Huerta, Depto. de Patología Animal (Reproducción), Facultad Veterinaria, Universidad de Zaragoza, C/ Miguel Servet 177, 50013 Zaragoza, Spain; E-mail: lydiagil@posta.unizar.es; Phone: +34 (976) 761 566; Fax: +34 (976) 761 612

Acta Veterinaria Hungarica 53 (2), pp. 249–255 (2005)

USE OF AGLEPRISTONE AND AGLEPRISTONE + INTRAUTERINE ANTIBIOTIC FOR THE TREATMENT OF PYOMETRA IN BITCHES

K. Gürbulak1*, Ş. M. Pancarci1, H. Ekici2, C. Konuk 2, I. Kirşan2, M. Uçmak2 and Seval Toydemir2

1Department of Obstetrics and Gynaecology, Faculty of Veterinary Medicine, University of Kafkas, 36100 Kars, Turkey; 2Department of Obstetrics and Gynaecology, Faculty of Veterinary Medicine, Istanbul University, Avcilar, Istanbul, Turkey

(Received February 17, 2004; accepted September 1, 2004)

In this study, the efficacy of aglepristone and/or intrauterine antibiotic administration for the treatment of bitches with cystic endometrial hyperplasia/pyometra complex was investigated. Twenty-four bitches (5–12 years old) with the diagnosis of pyometra were treated at the University of Kafkas and at Istanbul University. The diagnosis of pyometra was established on the basis of the results of clinical, ultrasonographic and vaginal examinations, the haematological and biochemical findings and the history data. In Group I (n = 13), aglepristone (Antiprogestin, Alizine®, Virbac, France; 0.33 ml/kg, s.c.) was administered on days 1, 2, 7, and 14 (day 1: diagnosis). In Group II (n = 11), intrauterine antibiotic treatment was performed according to the antibiogram on days 1, 2, 4, 6, 8 in addition to aglepristone given as in Group I. Clinical and ultrasonographic examinations, haematological results and occurrence of oestrous cycles revealed that the ratio of effectively treated bitches was 6/13 and 9/11 in Groups I and II, respectively.

Key words: Bitches, pyometra, aglepristone, intrauterine

*Corresponding author: Kutlay Gürbulak; E-mail: k_gurbulak@hotmail.com, gurbulak@kafkas.edu.tr; Phone: +90 (474) 242 6800/1237; Fax: +90 (474) 242 6853

Acta Veterinaria Hungarica 53 (2), pp. 257–264 (2005)

A MODIFIED SURGICAL TECHNIQUE FOR REPAIRING THIRD-DEGREE PERINEAL LACERATIONS IN MARES

G. Kaşikçi1, Huriye Horoz (Kaya)1, S. Alkan2, O. Düzgün3 and M. Aktaş3*

1Department of Obstetrics and Gynaecology, 2Department of Reproduction and Artificial Insemination and 3Department of Surgery, Faculty of Veterinary Medicine, Istanbul University, 34320 Istanbul, Turkey

(Received February 5, 2004; accepted September 1, 2004)

A modified surgical technique has been developed for repairing third-degree perineal lacerations in mares. Complications of the currently used methods include rectovaginal fistula formation, urine pooling, complete dehiscence of the repair, constipation, tenesmus and difficulty of performance in the practice. The modified method is simpler and more practical. This method was performed on eight Thoroughbred mares with third-degree perineal lacerations after delivery. The rectovestibular septum was reconstructed by three lines of sutures in a transverse direction in relation to the longitudinal axis of the rectum. In one of the eight cases pneumorectum was observed after using the new method. The conception rate obtained after using the new surgical technique was 62.5%. Pregnant mares delivered normally without any new lacerations at the subsequent parturition. It can be concluded that this new surgical technique can be used successfully for repairing third-degree perineal lacerations in mares.

Key words: Mare, perineal lacerations, surgical technique

*Corresponding author: Mustafa Aktaş; E-mail: aktasmus@hotmail.com; Fax: 0212 4737070/17297

Acta Veterinaria Hungarica 53 (2), pp. 265–273 (2005)

DETECTION OF BOVINE HERPESVIRUS 4 IN CD11B+ LEUKOCYTES OF EXPERIMENTALLY INFECTED RABBITS

Katalin Fábián1, Rita Ivanics2, Melinda Terényi2 and L. Egyed3*

1Institute for Veterinary Medicinal Products, Budapest, Hungary; 2Department of Veterinary Microbiology and Infectious Diseases, Faculty of Veterinary Medicine, Szent István University, Budapest, Hungary; 3Veterinary Medical Research Institute of the Hungarian Academy of Sciences, H-1581 Budapest, P.O. Box 18, Hungary

(Received November 8, 2004; accepted December 16, 2004)

The presence and numbers of bovine herpesvirus 4 (BoHV-4) infected CD11b+ leukocytes were investigated during experimental infections of New Zealand White rabbits by Fluorescence Activated Cell Sorter (FACS) analysis. Peripheral blood leukocytes (PBL) were collected every second day, and the cells were stained with phycoerythrin-labelled CD11b-specific mouse monoclonal antibody and fluorescein-conjugated bovine herpesvirus 4-specific mouse monoclonal antibody. The numbers of double-stained cells from PBLs of the control and inoculated groups were measured and compared in FACSTREK analyser. Double-stained cells were detected in the virus-inoculated group on postinoculation days (PID) 2–5 and 9–12. The results indicated that CD11b+ PBLs were permissive for BoHV-4 infection, and are probably the main reservoir of the virus during the latent period. The data did not indicate production of infectious viral particles, but virus-specific proteins were expressed on the surface of CD11b+ cells. The two waves of double-stained cells gave similar results to the PCR assays from serum samples, which showed the presence of viral DNA in the serum on the same days when virus-infected CD11b cells were also present. Productive BoHV-4 infection of mast cells or undifferentiated leukocytes in the bone marrow and the antiviral immune response might be responsible for this periodic appearance of the virus in CD11b+ PBLs and in the serum. The paper provides evidence that CD11b+ PBLs are the main target cell populations in the blood for BoHV-4.

Key words: Bovine herpesvirus 4, peripheral blood leukocytes, CD11b and BoHV-4 specific antibodies, FACS analysis, rabbit

*Corresponding author: László Egyed; E-mail: laci@vmri.hu; Phone: +36 (1) 467 4073; Fax: +36 (1) 467 4076