Investigation of the spread of brucellosis among human and animal populations in southeastern Bulgaria, 2007.

Three human cases of brucellosis were reported in summer 2007 in the region of Haskovo in southeastern Bulgaria. Subsequently, the regional veterinary and public health authorities carried out investigations to determine the spread of infection in domestic animals and in the human population. As a result, over 90,000 animals were tested, and 410 were found infected with brucellosis. The screening of 561 people believed to have been at risk of infection yielded 47 positive results. The majority of these persons had direct contact with domestic animals or had consumed unpasteurised dairy products. The investigations revealed evidence of disease among animals in the region and a considerable risk to humans, thus emphasising the need for effective prevention and control programmes.

The sensing of respiratory gases in fish: Mechanisms and signalling pathways.

Chemoreception in fish is critical for sensing changes in the chemical composition of the external and internal environments and is often the first step in a cascade of events leading to cardiorespiratory and metabolic adjustments. Of paramount importance is the ability to sense changes in the levels of the three respiratory gases, oxygen (O2), carbon dioxide (CO2) and ammonia (NH3). In this review, we discuss the role of piscine neuroepithelial cells (NEC), putative peripheral chemoreceptors, as tri-modal sensors of O2, CO2 and NH3. Where possible, we elaborate on the signalling pathways linking NEC stimulation to afferent responses, the potential role of neurotransmitters in activating downstream neuronal pathways and the impact of altered levels of the respiratory gases on NEC structure and function. Although serotonin, the major neurotransmitter contained within NECs, is presumed to be the principal agent eliciting the reflex responses to altered levels of the respiratory gases, there is accumulating evidence for the involvement of "gasomitters", a class of gaseous neurotransmitters which includes nitric oxide (NO), carbon monoxide (CO) and hydrogen sulphide (H2S). Recent data suggest that CO inhibits and H2S stimulates NEC activity whereas NO can either be inhibitory or stimulatory depending on developmental age.

An emerging role for gasotransmitters in the control of breathing and ionic regulation in fish.

Three gases comprising nitric oxide, carbon monoxide and hydrogen sulphide, collectively are termed gasotransmitters. The gasotransmitters control several physiological functions in fish by acting as intracellular signaling molecules. Hydrogen sulphide, first implicated in vasomotor control in fish, plays a critical role in oxygen chemoreception owing to its production and downstream effects within the oxygen chemosensory cells, the neuroepithelial cells. Indeed, there is emerging evidence that hydrogen sulphide may contribute to oxygen sensing in both fish and mammals by promoting membrane depolarization of the chemosensory cells. Unlike hydrogen sulphide which stimulates breathing in zebrafish, carbon monoxide inhibits ventilation in goldfish and zebrafish whereas nitric oxide stimulates breathing in zebrafish larvae while inhibiting breathing in adults. Gasotransmitters also modulate ionic uptake in zebrafish. Though nothing is known about the role of CO, reduced activities of branchial Na(+)/K(+)-ATPase and H(+)-ATPase activities in the presence of NO donors suggest an inhibitory role of NO in fish osmoregulation. Hydrogen sulphide inhibits Na(+) uptake in zebrafish larvae and contributes to lowering Na(+) uptake capacity in fish acclimated to Na(+)-enriched water whereas it stimulates Ca(2+) uptake in larvae exposed to Ca(2+)-poor water.

Increase in IDDM incidence in Bulgarian children (1974-1995).

The incidence of insulin-dependent diabetes mellitus (IDDM) in children on the Balkan peninsula varies between 2.45 and 10.00/100,000. The present study aimed to assess the trends in the IDDM incidence in children 0-14 years for a 22-year period in Eastern Bulgaria. The data were collected on the basis of the Varna Paediatric Diabetes Registry, both retrospectively and prospectively, with ascertainment of the primary source up to 98.8%. The mean annual IDDM incidence was 6.32/100,000 (95% CI 5.91-6.78), with the incidence in towns significantly higher than in villages: 7.24 vs 4.58/100,000, p < 0.0001. A linear trend of increase in the incidence with time was found, applying Poisson regression analysis. According to the model the age-adjusted incidence rose by 1.9% annually. The analysis revealed a significant linear trend of increase for children living in towns and for those aged 10-14 years.

Significant urban/rural differences in the incidence of type 1 (insulin-dependent) diabetes mellitus among Bulgarian children (1982-1998).

The systematic registration of the incidence of childhood (0-14 yr) type 1 (insulin-dependent) diabetes mellitus in Bulgaria dates back to 1973, with an invariably present difference in the incidence according to the area of residence. The present study has been undertaken to assess the trends in the incidence of type 1 diabetes among children in eastern Bulgaria (1982-1998) with respect to area of residence at onset. The data were collected prospectively, with an ascertainment of the primary source of 95.8%. The mean annual incidence is 6.99/100,000 (95% CI = 6.45-7.54), varying between 5.09 and 11.54/100,000. The mean annual incidence in towns is higher than in villages: 7.89 vs. 5.26/100,000, p < 0.0001. A linear trend of increase in the incidence with time is revealed applying Poisson regression analysis, with the area of residence as a strong predictor of the risk (p < 0.001). According to the model, the age-adjusted incidence rose by 4.1% annually. The stratified analysis by age group has found a significant linear trend in those aged 5-9 (p < 0.001) and 10-14 yr (p = 0.002) for both sexes. In conclusion, the markedly increasing incidence of type 1 diabetes among children in this study is strongly dependent on area of residence at onset. We suggest that in conjunction with the pronounced seasonality at the onset of diabetes and its connection with population density, this phenomenon should be regarded as a reflection of environmental influence and further explored.