Dragan Vasilev

First report of Trichinella britovi in Serbia

In Europe, Serbia ranks among countries with a high prevalence of Trichinella infection in pigs, which continues to be a serious human health problem. While in some Balkan countries, more than one Trichinella species/genotype has been described in both the sylvatic and domestic cycles, these data are lacking for Serbia. To date, only a few Serbian isolates of Trichinella have been genetically specified, and all were classified as T. spiralis. Although transmission of Trichinella from domestic pigs to wildlife could be assumed, neither the infection status nor the species of Trichinella circulating among wildlife in Serbia has been investigated. This study shows the presence of two Trichinella species, T. spiralis and T. britovi, in wild animals originating from five districts in Serbia, where Trichinella infections in domestic pigs and humans have been recorded. Trichinella spiralis was detected in jackals (n = 3), red foxes (n = 2) and a wild cat (n = 1). We also established that wolves (n = 4) and red foxes (n = 2) serve as sylvatic reservoirs for T. britovi. This is the first report on the presence of T. britovi in Serbia.

A large-scale study of the Trichinella genus in the golden jackal (Canis aureus) population in Serbia.

Over the last decades the golden jackal (Canis aureus) has significantly expanded its range throughout Southeast and Central Europe, and the Balkan Peninsula is considered to be a core area of the species distribution in this part of the range. Due to its increasing number, ability of long distance movement through a wide range of landscapes and opportunistic feeding habits, the golden jackal may represent an important reservoir and transmitter of a variety of zoonotic agents, including parasites. The Balkans, Serbia included, remain an endemic area for various zoonotic parasites including Trichinella spp. Trichinella has recently been recorded in jackals in Serbia, which prompted us to carry out a large-scale survey of its prevalence, distribution and species identification in this host. In cooperation with local hunters, carcasses of a total of 738 legally hunted golden jackals were collected at 24 localities over an 11-year period (2003-2013). Analysis of tongue base tissue revealed Trichinella larvae in 122, indicating a prevalence of infection of 16.5%. No difference in the prevalence of infection was found between genders [16.2% in males and 16.9% in females (χ(2)=0.05, p=0.821)], or among the study years (G=7.22, p=0.705). Trichinella larvae were found in 13 out of the 24 examined localities. Molecular identification was performed for 90 isolates, and 64 (71.1%) larvae were identified as Trichinella spiralis and 25 (27.9%) as Trichinella britovi. Mixed infection (T. spiralis and T. britovi) was recorded in a single case. Although T. spiralis was more prevalent, T. britovi had a wider distribution, and was the only recorded species in jackal populations from the mountainous region of eastern Serbia. On the other hand, T. spiralis was dominant in jackals in the lowlands of central and northern Serbia, where domestic pigs are mostly reared. These results show that the golden jackal is involved in both the domestic and sylvatic cycle, and that it has emerged as a major host species in the sylvatic cycle of the Trichinella genus. Therefore, continued monitoring of Trichinella infection in golden jackals in Serbia and the whole of the Balkans is recommended in order to control transmission of this parasite to humans and domestic animals.

The Wolf (Canis lupus) as an Indicator Species for the Sylvatic Trichinella Cycle in the Central Balkans

Abstract Wildlife is the most important reservoir of Trichinella spp. worldwide. Although the Balkans are a recognized European endemic region for Trichinella infections, data on wildlife are scarce. To monitor the circulation of these zoonotic parasites in the Central Balkan region, the wolf (Canis lupus) was selected because of its abundance (>2,000 individuals) and because it is at the top of the food chain. A total of 116 carcasses of wolves were collected in Serbia and in the neighboring areas of Macedonia and Bosnia and Herzegovina (B&H) between 2006 and 2013. Trichinella spp. larvae were found in 54 (46.5%) wolves. The great majority (90.5%) originated from Serbia, where 52 of the 105 examined animals were Trichinella positive (49.5%; 95% confidence interval  = 39.9–59.1). One positive animal each was found in B&H and Macedonia. All larvae were identified as Trichinella britovi. The high prevalence of Trichinella infection in wolves suggests that this carnivore can be a good indicator species for the risk assessment of the sylvatic Trichinella cycle in the Central Balkans.

Detection of icaA and icaD genes of Staphylococcus aureus isolated in cases of bovine mastitis in the Republic of Serbia

Abstract Staphylococcus aureus (S. aureus) is the most common agent of contagious mastitis that causes serious health and economic problems. The ability to form biofilms is an important virulence factor of S. aureus for the establishment of persistent infections. This study is aimed to investigate the presence of icaA and icaD, two genes of importance for the biofilm formation in S. aureus bovine mastitis isolates. In order to isolate and identify S. aureus, 1555 milk samples were collected from 401 cows, located in different regions of the Republic of Serbia. Using the conventional microbiological methods 100 isolates were characterized as coagulase-positive staphylococci. After primary biochemical identification, the species confirmation of 44 S. aureus isolates was done using MALDI-TOF Mass Spectrometry and PCR technique, targeting the S. aureus-specific nuc gene. Among all investigated S. aureus isolates 25.0% harbored both icaA gene and icaD genes. The presence of icaD gene alone was confirmed in 40.9% of cases totaling icaD positive isolates to 65.9%. The remaining 34.1% of S. aureus isolates were negative for the presence of both genes. The results of the present study indicate the existence of potential biofilm-producer strains in different regions of the Republic of Serbia, both under intensive and semi-extensive cows breeding.

VIRUSI - AKTUELNI ALIMENTARNI PATOGENI

Virusne infekcije prenosive hranom sve se češće javljaju u mnogim delovima sveta. Procena realne zastupljenosti virusnih bolesti koje se prenose putem hrane otežana je usled neprijavljivanja infekcija i nepostojanja sveobuhvatnih sistema za nadzor. Nekoliko grupa virusa može izazvati oboljenje ljudi nakon konzumacije kontaminirane hrane. Na osnovu simptoma infekcije, mogu se razvrstati na: one koji izazivaju gastroenteritis (Norovirus-NoV, Rotavirus-HRV, Astrovirusi, Adenovirusi i Sapovirusi), zatim one koji iz creva migriraju u jetru i uzokuju hepatitis (Hepatitis A-HAV i Hepatitis E-HEV) i virusi koji se umnožavaju u crevima, a do bolesti dovode jedino ako migriraju u druge organe, na primer u centralni nervni sistem (Enterovirusi). Trenutno najznačajniji alimentarni patogeni su Norovirus (NoV) i Hepatitis A virus (HAV). Svi pomenuti virusi se šire fekalnom kontaminacijom, ali i direktnim kontaktom ili transmisijom virusnih čestica putem aerosola. Hrana može biti primarno kontaminirana virusom ili naknadno tokom čitavog lanca hrane. Virusi se u njoj ne razmnožavaju, ali mogu opstati duži vremenski period ili u samoj hrani, ili kao infektivne čestice u okruženju. Danas dostupna Real Time RT-PCR metoda je glavna tehnika detekcije virusa u hrani, vodi i drugim uzorcima. Kao preventivne i kontrolne mere u sprečavanju virusnih infekcija preko hrane preporučiju se: podizanje svesti rukovaoca hranom standardizacija metoda za detekciju virusa u hrani razvoj laboratorijski baziranog nadzora za otkrivanje izvora epidemije u ranoj fazi, kao i naglašavanje značaja razmatranja virusa u integrisanim sistemima za bezbednost hrane (GHP, GMP, HACCP). Osim toga, naglašava se i značaj uvođenja monitoringa virusa u hrani, u cilju poboljšanja zaštite javnog zdravlja.

The interactive effects of transportation and lairage time on welfare indicators, carcass and meat quality traits in slaughter pigs

This study assessed the effects of transportation and lairage time and their interaction on welfare, carcass and meat quality traits in slaughter pigs under commercial conditions. The study was conducted on 120 pigs with a live weight of approximately 115 kg and about six months old. A complete blood picture was measured in pigs to assess pre-slaughter stress. Also, nine different carcass quality parameters including live weight, hot and cold carcass weights, cooling loss, dressing percentage, backfat thickness, meatiness and skin lesions score were measured. The pH and temperature measurements were performed 45 minutes post-mortem. The results showed that short transportation time and slaughtering without lairaging and long transportation time and overnight lairaging negatively influenced the hematological parameters, which meant that the animal welfare was seriously compromised under these pre-slaughter conditions. Long transportation time and overnight lairaging reduced live and carcass weights and increased the incidence of skin lesions on the carcass and DFD pork. In addition, short transportation time and slaughtering without lairaging caused a significant deterioration in pork quality. It can be concluded that, from the standpoint of animal welfare, carcass and meat quality, the above-mentioned pre-slaughter conditions are not recommended to the farmers and/or pork producers.

Perspectives in production of functional meat products

The meat industry has met new challenges since the World Health Organization classified processed meat in carcinogenic Group 1. In relation to this, the functional food concept in meat processing has gained importance, especially in reducing carcinogenic N-nitroso compounds and polycyclic aromatic hydrocarbons (PAHs) as an additional imperative, apart from the usual fat and salt reduction and product enrichment with functional ingredients. PAH reduction relies on control of the smoking process, but there is also a possibility they could be degraded by means of probiotic microorganisms or spices. The reduction of N-nitroso compounds could be provided by lowering the amount of added nitrite/nitrate, using substitutes for these chemicals, and/or by preventing conditions for the creation of N-nitroso compounds. Nevertheless, fat and salt reductions still remain topical, and rely mostly on the use of functional ingredients as their substitutes.

Some risk factors that affect contamination of mussels (Mytilus galloprovincialis) from the Bay of Kotor, Montenegro

Pollution and contamination of the Bay of Kotor ecosystem arise from both anthropogenic sources and natural weathering. In recent decades, a need has arisen for regular control of marine organisms, which are used in human nutrition, because the entire bay is constantly and increasingly exposed to negative anthropogenic impact. Molluscs, including mussels (Mytilus galloprovincialis), can be involved in foodborne disease. They are filter feeding organisms, able to retain and concentrate in their bodies the bacteria, parasites, viruses and biotoxins of marine algae present in their external environment. A structured field study was undertaken in the Bay of Kotor, Montenegro, in order to investigate plausible influence of environmental factors, like rainfall and temperature, on the variability of Escherichia coli and norovirus (NoV). This study focuses on human-derived pathogens that are abundant in sewagerelated sources. We proved the negative correlation between outside temperature and the number of E.coli and the presents of Norovirus in Bay of Kotor mussel. We used this data from the sampling site to discuss options to better manage the risk of contamination of shellfish. From the aspect of food safety, an upgrade of monitoring plans in the future could lead to obtaining safer products.

Influence of Environmental Conditions on Norovirus Presence in Mussels Harvested in Montenegro

This study comprises the first systematic survey of the occurrence of Norovirus in Mediterranean mussels from harvesting areas in Montenegro coast of Adriatic Sea. Mussels may accumulate contaminants of public health concern, including pathogenic bacteria and viruses. Microbiological monitoring of harvesting areas is based on count of Escherichia coli in bivalve molluscs in the European Union. It is assumed that E. coli does not reflect contamination with enteric viruses. A structured field study was undertaken at six locations in Bay of Kotor, Montenegro, in order to investigate plausible influence of environmental factors on the variability of E. coli and norovirus (NoV). From July 2015 to July 2016, a total of 72 samples of mussels were collected in coastal harvesting areas of the Montenegro. The samples were screened for NoV of genogroups GI and GII using reverse transcription-qPCR (RT-qPCR). There were 43% NoV positive samples with higher presence of genogroup GII (74.2%). With regard to influence of environmental conditions on Norovirus presence, we have proved seasonal pattern of virus occurrence i.e., the largest number of positive samples was noticed during winter, while other physico-chemical factors were not of great significance. It was found that count of E. coli did not correlate with Norovirus prevalence. From the aspect of food safety, an upgrade of monitoring plans could lead to obtaining safer products.