Cytokines as intercellular signal molecules are responsible to a great extent for the pathological processes in Salmonella infection, as well as for the development of protective mechanisms in the disease. The present study aimed to reveal the correlation between serum levels of IFN-gamma, IL-12, TNF-alpha and IL-10, measured by enzyme-immunoassay, and clearance of bacteria in stool of patients with gastroenteric Salmonella infection. The study included 36 patients with culture confirmed gastroenteric Salmonella infection. At discharge from hospital, 20 patients recovered with bacteriological negative stool culture for Salmonella and 16 were Salmonella excretors. Mean serum concentrations of IFN-gamma, IL-12, TNF-alpha and IL-10 in the acute stage were compared between the 2 groups of patients and with those of healthy controls. Serum levels of examined cytokines were increased (p<0.001) in the patients in comparison with the healthy controls. In patients with early bacterial clearance mean serum concentrations of IFN-gamma, IL-12 and TNF-alpha in the acute stage were significantly (p<0.05) higher than in the non-clearance group. IL-10 serum level showed an opposite correlation (p<0.01) and higher values in Salmonella excretors. The accumulated data imply that Th1 type cytokines probably participate in protective immunity and early bacterial clearance in patients with gastroenteric Salmonella infection.

An aseptic meningitis outbreak emerged in two regions in Bulgaria in 2012 and echovirus 30 (E30) was established as the aetiological agent by cell culture isolation, serological test, and molecular-based techniques. A total of 157 patients with aseptic meningitis were investigated, of which 117 were confirmed as having E30-associated disease. Molecular analysis of 12 E30 isolates revealed 99-100% nucleotide and amino-acid identity between them and a close correlation with a Greek strain involved in an E30 outbreak in 2012. Children aged 5-14 years were mainly affected, which could reflect the absence of E30 epidemics in Bulgaria for a period of 11 years. The first case with E30 isolation (a 2-year-old patient from Plovdiv) was notified at the end of April 2012. This was most likely the index case, from which the spread of the virus started, causing sporadic cases first, which later led to an aseptic meningitis outbreak facilitated by person-to-person viral transmission.

The present report describes for the first time comparative analysis of epidemiological features, clinical manifestations and laboratory findings of DOBV and PUUV infections in Bulgaria.

Salmonella bacteria are the major cause of food-borne infectious diarrhea. There is great interest in understanding the pathogenesis and immunogenesis of Salmonella infection. Cytokines are key communicator molecules between host cells and the enteric pathogen Salmonella. Serum levels of IL-1, IL-1ra, IL-6, IL-10, IL-12, TNF-α and IFN-γ were studied in a prospective controlled study including 36 patients at the acute stage of gastrointestinal salmonellosis. Correlation between them was investigated, as well as between cytokines, body temperature and serum levels of Na + , K + and Cl-. The lowest correlation was found between TNF-α and IL-1ra. A significant and directly proportional correlation was established between IL-12 with IFN-γ and TNF-α, as well as in TNF-α/IL-1β and IL-1β/IL-1ra. The increased body temperature correlated significantly with IL-1β, TNF-α and IL-6. Significant but converse was the correlation between Na + with IL-1β and IL-6, as well as between body temperature with Na + , K + and Cl-. Our data imply evidence for the complicated network in which cytokines act with multiple potential synergistic and antagonistic effects between them participating in the main pathogenetic processes-intoxication and loss of fluids and electrolytes.

In a representative nationwide study, we have determined the prevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) coinfections among HIV-positive patients diagnosed during the period 2010-2014 in Bulgaria. Despite a relatively low rate of new HIV diagnoses, the rates of hepatitis B and C coinfections among these patients fell within the upper range reported in Europe. HBsAg and HCV antibodies (Ab) were found in 10.4% and 25.6% of the tested individuals, respectively. Importantly, high rates of active hepatitis infections were confirmed by detection of HBV DNA in 51.1% and HCV RNA in 78.1% of the tested individuals. Hepatitis coinfections affected mostly high risk groups and persons with multiple risk behavior, including people who inject drugs, men who have sex with men, prisoners, and Roma people.