Bovine Tuberculosis in the Republic of Macedonia: Postmortem, Microbiological and Molecular Study in Slaughtered Reactor Cattle

Bovine tuberculosis is a chronic infectious disease in cattle caused mainly by Mycobacterium bovis and to a lesser extent by Mycobacterium caprae. The other members of the Mycobacterium tuberculosis complex (MTBC) can also cause the disease in domestic and wild animals and all of them have a zoonotic potential. The main purpose of the study was to determine the presence and distribution of the tuberculous lesions in reactor cattle, and to isolate and identify the causative agents of bovine tuberculosis in the Republic of Macedonia. Lymph nodes and affected organs from 188 reactor cattle slaughtered due to a positive intradermal comparative cervical tuberculin test were analyzed by detection of tuberculous lesions, followed by isolation and molecular identification of the isolated mycobacteria. The isolation was performed on selective media - Lowenstein Jensen with glycerol, Lowenstein Jensen without glycerol and Stonebrink medium supplemented with pyruvate. The molecular identification of the MTBC members was performed by analysis of the Regions of difference (RD1, RD9 and RD4) and detection of single nucleotide polymorphisms in the lepA gene for Mycobacterium caprae. Typical tuberculous lesions were detected in 62 animals (33.0%) and the lesions were most prevalent in the mediastinal lymph nodes (47.5%). The isolated mycobacteria in the MTBC were identified as Mycobacterium bovis and Mycobacterium caprae and were found in both animals with visible lesions (82.2%) and animals without visible lesions (27.7%). The slaughterhouse postmortem examinations and laboratory investigations should be included on regular bases in order to improve the National eradication program.

Sheep and goats as indicator animals for the circulation of CCHFV in the environment

Crimean-Congo hemorrhagic fever virus (CCHFV) is a tick-borne virus, which causes a serious illness with case-fatality rates of up to 80% in humans. CCHFV is endemic in many countries of Africa, Asia and Southeastern Europe. Next to the countries with endemic areas, the distribution of CCHFV is unknown in Southeastern Europe. As the antibody prevalence in animals is a good indicator for the presence or absence of the virus in a region, seroepidemiological studies can be used for the definition of risk areas for CCHFV. The aim of the present study was to reveal which ruminant species is best suited as indicator for the detection of a CCHFV circulation in an area. Therefore, the prevalence rates in sheep, goats and cattle in different regions of Albania and Former Yugoslav Republic of Macedonia were investigated. As there are no commercial tests available for the detection of CCHFV-specific antibodies in animals, two commercial tests for testing human sera were adapted for the investigation of sera from sheep and goats, and new in-house ELISAs were developed. The investigation of serum samples with these highly sensitive and specific assays (94-100%) resulted in an overall prevalence rate of 23% for Albania and of 49% for Former Yugoslav Republic of Macedonia. Significant lower seroprevalence rates for CCHFV were found in cattle than in small ruminants in given areas. These results indicate that small ruminants are more suitable indicator animals for CCHFV infections and should therefore be tested preferentially, when risk areas are to be identified.

Application of Fluorescence Based Molecular Assays for Improved Detection and Typing of Brucella Strains in Clinical Samples

Bacteria from the genus Brucella are causative agents of brucellosis - a zoonotic disease which affects many wild and domestic animal species and humans. Taking into account the significant socio-economic and public health impact of brucellosis, its control is of great importance for endemic areas. The chosen control strategy could be successful only if adapted to the current epidemiological situation. This implies that a choice of appropriate diagnostic procedures for detection and typing of Brucella spp. strains are of essential importance. Significant advancement of molecular techniques and their advantages compared to classical methods, give strong arguments in promotion of these techniques as a powerful tool for comprehensive diagnostics of brucellosis. Considering this, the major tasks of the study were to select and implement molecular tests for detection and genotyping Brucella spp. and evaluate their performances using DNA from cultivated brucellae (islolates) and limited number of tissue samples from seropositive animals. The obtained results confirmed that implemented real time PCR for Brucella spp. detection, as well as MLVA-16 used for genotyping, have excellent analytical sensitivity (4.2 fg of Brucella DNA were successfully detected and genotyped). Furthermore, compared to bacteriological cultivation of Brucella spp., real time PCR and MLVA-16 protocols showed superior diagnostic sensitivity and detected Brucella DNA in tissues from which Brucella could not be cultivated. Based on the summarized study results, we propose a diagnostic algorithm for detection and genotyping of Brucella spp. bacteria. Routine use of proposed diagnostic algorithm will improve the effectiveness of infection confirmation and help for accurate evaluation of epidemiological situation.

Sow Productivity on Commercial Pig Farms in the Republic of Macedonia

The objectives of the present study were to determine the production performances of sows on commercial pig farms in the Republic of Macedonia, to compare the differences in sow productivity data between small and large farms and to examine interrelationships of key production parameters among farms with different sizes. The study was retrospectively based and included the annual (2012) analyses of the sow productivity data in small (<200 sows, n=4) and large (200-1000 sows, n=5) commercial pig farms. The data was statistically evaluated and compared with the known literature. Sows productivity was greater on the small farms compared to the large ones. The small farms had larger litter per sow (PBL), more pigs born alive (PBA), higher weaning weight (WW) and more pigs weaned per sow per litter (PWSL) than the large ones (p<0.001). Small farms also had greater farrowing rate (FR) (p<0.01). Higher replacement rate (RR), lower average parity (AP), greater number of litters per sow per year (LSY) and higher sow death rate (SDR) were observed in large farms (p<0.001). The large farms also had less non-productive days (NPD) than the small farms (p<0.001). Different intensity of correlations also were observed for several productive parameters among the farm groups. The data obtained in this study show that sow productivity on Macedonian pig farms is lower than in EU countries. Small herds are more efficient than the large herds. Despite all limitations, our study provides information for veterinarians regarding reproductive parameters of sows and their interrelationships on Macedonian pig farms. Further investigation should be made in order to identify whether specific management factors have effect on the productivity of the breeding herd.

Circulation of Crimean-Congo Hemorrhagic Fever Virus in the former Yugoslav Republic of Macedonia revealed by screening of cattle sera using a novel enzyme-linked immunosorbent assay

BACKGROUND

There are only few assays available for the detection of Crimean-Congo Hemorrhagic Fever Virus (CCHFV)-specific antibodies in animals, and data about diagnostic sensitivity and specificity are incompletely documented for most of these tests. This is unfortunate since CCHFV antibodies in animals can be used as indicator for virus circulation in a geographic area and therewith potential risk of human exposure. This paper therefore reports on a novel ELISA for the detection of CCHFV-specific antibodies in cattle and on its application for testing ruminant sera from the Former Yugoslav Republic of Macedonia.

PRINCIPAL FINDINGS

A highly sensitive and specific ELISA was developed to detect CCHFV-specific IgG antibodies in cattle. The assay was validated by using 503 negative serum samples from a country where CCHFV has never been detected until now, and by using 54 positive serum samples. The positive sera were verified by using two commercially available assays (for testing human serum) which we have adapted for use in animals. The sensitivity of the novel ELISA was 98% and its specificity 99%. The presence of Hyalomma ticks was demonstrated in the Former Yugoslav Republic of Macedonia and depending on the region antibody prevalence rates up to 80% were detected in the cattle population.

CONCLUSION

This article describes a fully validated, highly sensitive and specific ELISA for the detection of CCHFV-specific IgG antibodies in cattle. Using this assay, CCHFV-specific antibodies were detected for the first time in cattle in the Former Yugoslav Republic of Macedonia, giving evidence for an active circulation of this virus in the country. Supporting this conclusion, the occurrence of the main vector of CCHFV was demonstrated in the present work for the first time in Former Yugoslav Republic of Macedonia.

Molecular characterisation of rabies virus strains in the Republic of Macedonia

Rabies, a worldwide zoonosis, remains a public-health concern despite oral wildlife vaccination in Europe. After a ten-year break, Macedonia reported eight rabies cases in 2011-2012. Two countries (Serbia and Bulgaria) bordering Macedonia are reporting cases in domestic and wild animals. This report describes the genetic characterisation of eight isolates from Macedonia compared with representative samples from neighbouring countries. All of the isolates tested belong to the Eastern European group, with a high degree of nucleotide sequence identity in the nucleoprotein gene. The close genetic relationship between isolates from the three bordering countries suggests that wildlife is responsible for rabies movements in the region.