Yolanda Vaz Veterinarian Professor, Faculdade de Medicina Veterinária, Universidade de Lisboa Brucellosis is an infectious disease caused by bacteria of the genus Brucella. It is also known as Malta fever, Mediterranean fever, or undulating fever. It can affect different animal species, domestic and non-domestic, and man. It is transmitted from animals to man and, therefore, it is a zoonosis. It is a notifiable disease , both in man and in animals. Brucellosis transmission In livestock species, brucellosis is cause of significant economic losses . It is associated to abortion in the last third of pregnancy, birth of weak animals and infertility in males. Elimination of bacteria in the tissues of abortion and childbirth takes place and these are an important source of transmission of the disease between animals, which is done mainly by oral route. The c ontagion of brucellosis to humans can occur by: Consumption of raw milk, dairy products (especially fresh cheese and butter) prepared from unpasteurized milk or other products from infected animals; Skin and mucosa contact with tissues or fluids (urine, blood, milk) from infected animals; Inhalation of aerosols produced in heavily contaminated locations. Due to the characteristics of its transmission, brucellosis is an occupational disease in workers of livestock farms, slaughterhouses, dairy industries, laboratories and veterinarians. Prevention of brucellosis The control of brucellosis and the prevention of transmission of the disease to man is done mainly by: Surveillance of disease in animals; Mandatory pasteurization of milk for commercialization and preparation of dairy products, with the exception of long-lasting cure cheeses; Implementation of specific protection measures to reduce occupational risk. Individually it is important: Be careful not to consume raw milk or milk products (for example fresh cheese, butter, among others) prepared from raw milk, that is, milk without heat treatment; Avoid contact of skin and mucous membranes with tissues or fluids from infected or suspect animals and abortion products. Surveillance of disease in animals In Portugal, the control of the disease in livestock of dairy animals - cows, sheep, and goats - has been a concern since the 1950. Later, in 1991, a program for the eradication of the disease was initiated, supported by European funds, and implemented by the national authorities. This eradication program, which aims to eliminate brucellosis from domestic animals and thereby reduce the risk of infection and protect human health, has several measures , for example: Annual serological screening, with blood collection from all cattle, sheep and goats of reproductive age; Investigation of abortion outbreaks or other suspected cases of infection; Slaughter and elimination of all identified positive cases; Restriction of movement of animals, epidemiological survey to identify the source of the infection and possible contamination from other farms and regular testing of the animals, until guarantee of no infection; Application of other measures, such as vaccination, cleaning and disinfection and sanitary break, interdiction of production of dairy products without heat treatment of milk, long-lasting maturation of cheeses mandatory. Based on the results of the brucellosis eradication program, each ruminant farm in Portugal and each geographic region has a health classification for brucellosis . In 2020, according to the Direção Geral de Alimentação e Veterinária, 99.6% of bovine and 97.3% of sheep and goat farms were free from the disease. According to data from the Direção Geral da Saúde, in 1989 there were 1576 cases and in 2019 there were 33 cases of human brucellosis. Also know that: Brucellosis is known since the late 19th century, when the bacterium that causes it was first isolated by a British military doctor, Sir David Bruce , who described the disease in his soldiers on the island of Malta. It was also on this island that it was known, some years later, that the origin of the disease was the consumption of raw milk from sick animals , in this case of goats, and it was realized that this disease was a zoonosis. At that time, it was mandatory to boil the milk before its consumption and the cases of illness decreased rapidly. In Portugal , the first report of the disease dates from 1893. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
