West Nile virus (WNV), a neurovirulent mosquitotransmissible zoonotic virus, has caused recent outbreaks in Europe, including Serbia from August until October 2012. Although humans can be infected, birds are the main natural WNV reservoir. To assess WNV circulation in northern Serbia, 133 wild birds were investigated. These comprised resident and migratory birds, collected between January and September 2012 in the Vojvodina province. The birds belonged to 45 species within 27 families. Blood sera (n=92) and pooled tissues from respective birds (n=81) were tested by enzyme-linked immunosorbent assay (ELISA), plaque reduction neutralisation test (PRNT) and real-time reverse transcription-polymerase chain reaction (RT-qPCR). WNV antibodies were detected in seven (8%) sera: four from Mute Swans (Cygnus olor), two from White-tailed Eagles (Haliaeetus albicillas), and one from a Common Pheasant (Phasianus colchicus). Five sera neutralised WNV but not Usutu virus. For the first time in Serbia, WNV RNA was detected by RT-qPCR in pooled tissue samples of eight respective birds. WNV RNA was also derived from an additional bird, after a serum sample resulted infective in cell culture. The total nine WNV RNA positive birds included three Northern Goshawks (Accipiter gentilis), two White-tailed Eagles, one Legged Gull (Larus michahelis), one Hooded Crow (Corvus cornix), one Bearded Parrot-bill (Panarus biramicus), and one Common Pheasant. Phylogenetic analysis of partial E region sequences showed the presence of, at least, two lineage 2 Serbian clusters closely related to those responsible for recent human and animal outbreaks in Greece, Hungary and Italy. Full genomic sequence from a goshawk isolate corroborated this data. These results confirm WNV circulation in Serbia and highlight the risk of infection for humans and horses, pointing to the need for implementing WNV surveillance programmes.

Sodium, potassium and chlorides play a crucial role in maintaining body acid-base balance as well as osmotic pressure in body fluids. These processes are the result of synergetic action of all three elements, and the role of each individual component is diffi cult to defi ne without knowing and taking into consideration the other two elements. The maintenance of this value is determined by three major factors – balance and ratio ofelectrolytes in feed, endogenous acid production and level of renal activity. Electrolyte imbalance is quite rare, since body’s buff ering system provides maintenance of normal physiological pH value. Th is article will give an overview of the role, importance and needs of poultry for sodium, potassium and chlorides, as well as occurrences related to defi cit and the imbalance of those elements in feed.

Th e results of our 15-year long research on the eff ects of global warming in our region that relies on the database obtained from the Republic Hydrometeorological Service of the Republic of Serbia strongly suggested changes in the pattern of disease events associated with inevitable occurrence of heat stress in poultry regardless of the species and category. Having in mind the accelerating global warming and geographic position of Serbia the occurrence of frequent cyclical and intense meteorological extremes is expected (Kapetanov et al., 2011; Kapetanov et al., 2013; Kapetanov et al., 2013). In our country and surrounding regions characterized by continental climate, the risk from the heat stress in poultry production is limited to summer months. Still, summer period has been getting longer and is associated with increasing trend of tropical days and annual trend of global warming spreading of 0.2o geographic latitude. Heat stress of poultry is one of the most challenging problems of poultry production causing substantial damages and aff ecting all parameters of production performance and is oft en associated with sudden and massive deaths. Having in mind the aforementioned data, the objective of our research was monitoring of changes in mortality structure associated with temperature oscillations during production process with an aim of emphasizing some major sources, consequences and preventive measures related to heat stress.

Meat, table eggs and their products are very important in human nutrition. Therefore, it is necessary to monitor the health status of commercial flocks as much as the quality of poultry products in the food chain. Campylobacter sp. and Salmonella sp. are widely distributed in nature. The influence of these bacteria on animal health depends on the immune response. If animals are not immunologicaly compromised, the infection is latent and clinical symptoms are absent. Unlike animals, these bacteria cause serious diseases in humans and the morbidity is quite high. The main transfer of infection to humans is via poultry products. The goal of this work was to study the role of Salmonella in artificially infected chickens onto the outcome of clinical campylobacteriosis. It is certain that salmonella infection in poultry damages the immune system of chickens, enabling Campylobacter to multiply and subsequently induce a disease. Three groups of chickens were included in the experiment. The first group received a suspension of field strain of Campylobacter jejuni (C. jejuni) and Salmonella enterica serovar Enteritidis (S. Enteritidis). The second group received an inoculum prepared from the field isolate of Campylobacter jejuni and the third group received the field isolate of Salmonella enterica serotype Enteritidis, only. In artificially infected chickens Campylobacter and Salmonella were confirmed by isolation and identification according to morphological, cultural and biochemical properties. Humoral immune response of infected chickens was monitored using the complement fixation test (CFT). In chickens infected with C. jejuni and S. Enteritidis the clinical symptoms were recorded. The results from this experiment show that salmonella infection damages the immune system of the chickens enabling Campylobacter to alter the health status of the host

For over 10 years infectious laringotracheitis has occurred rarely in Vojvodina. In such situations morbidity was 40% and mortality was 16%. Drop in egg production was over 30% and after 4 weeks egg production returned to normal. After the disappearance of clinical symptoms and after 30 days of quarantine and disinfection of eggs with formaldehyde and 5% hydrogen peroxide there was no appearance of the disease in hatched chickens. Clinical observation and pathohistology results are valuable proof for diagnosis of ILT. Diagnosis of ILT should be confirmed by virus isolation or applying serological tests such as ELISA on sera from diseased chickens