2007: Bulgarian Brucellosis in Humans and Animals

EU - 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.

1 May 2009

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As a result, over 90,000 animals were tested, and 410 were found infected with brucellosis, reports Eurosurveillance. 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.

Introduction

Brucellosis, also called undulant fever or Malta fever, is a zoonotic infection caused by Gram-negative bacteria of the genus Brucella. Brucella melitensis affects predominantly small ruminants, such as goats and sheep, B. аbortus is found mainly in cattle and B. suis in pigs, whereas B. canis occurring in dogs is the least common. Transmission to humans may take place by direct contact with affected animals or their post-partum/post-abortion secretions, by ingestion of contaminated, unpasteurised food (mainly dairy products), and by inhalation of infected aerosols. The potential to infect humans and animals through aerosol exposition has raised the possibility of deliberate use of Brucella spp. as a biological weapon .

The mean incubation period in humans is 2-10 weeks, but could range from several days up to six months. The symptoms include intermittent fever, chills, asthenia, fatigue, weakness, malaise, arthralgias, low back pain, headache, anorexia. Chronic untreated brucellosis can lead to osteoarticular or, less commonly, genitourinary complications, in some cases even death.

Globally, brucellosis remains a serious problem, with more than 500,000 cases per year worldwide. In Europe, brucellosis affects mainly the Mediterranean countries, but the epidemiology of this infection has been changing over the past decade due to various sanitary, socioeconomic, and political factors, and to international travel. In 2006, a total of 1,313 human cases, of which 955 were confirmed, were reported in the European Union (EU) countries, representing a notification rate of 0.20 per 100,000. Twelve countries reported zero cases. The highest notification rates per 100,000 were reported by Greece (1.1), Italy (0.78), Portugal (0.72) and Spain (0.3).

In Bulgaria, since 1903, only sporadic cases had been reported in humans. However, during the last few years, the numbers increased; 37 cases were reported in 2005 and 11 in 2006. In 2007, in the course of the investigations described in this paper, 50 cases were identified in the province of Haskovo in southeastern Bulgaria, which brought the total number of cases registered in the country to 57.

The investigations reported here were undertaken after three cases with clinical symptoms and laboratory confirmation of brucellosis had been detected in the town of Harmanli (two cases) and a nearby village of Valche pole (one case) in the Haskovo region. The objectives were to determine the spread of disease in domestic animals, conduct active case-finding in the human population potentially exposed to infection, identify risk factors and provide recommendations for appropriate control and response measures.