Often travel is also associated with curiosity about the culinary culture of the country one decides to visit. We all know that, in some parts of the planet, it is better not to drink water that is not bottled or to trust the ice cubes used to cool drinks; however, sometimes we forget that there are other foods to which we should also pay attention.
In industrialized countries, milk and its derivatives are almost always pasteurized before their consumption or use for cheese production (with the obvious exception of raw milk), but this is not the rule in other countries.
Brucellosis (also known as Maltese fever, melitensis fever, Mediterranean fever, Cyprus fever, Gibraltar fever, undulant fever, intermittent typhus) isa zoonosis, that is, a disease that is transmitted from animal to human, caused by bacteria belonging to the genus Brucella.
Brucellosis affects several types of animals, including cows, sheep, goats, deer, pigs and dogs. The infection culprits are six species of gram-negative bacteria belonging to the genus Brucella: B. melitensis, B. aboutus, B.suis, B. canis, B. ovis, B. neotomae. The first four are also capable of infecting humans.
.B. melitensis is, among them, the most invasive and related to more severe forms of disease, so it is considered the main cause of human brucellosis. In many developed countries (Europe, Australia, New Zealand, Canada, Japan, Israel), the annual incidence is 0.3 cases per million, so the disease can be considered essentially eradicated; in contrast, Brucellosis remains a public health problem in some areas where it is still endemic: Africa, the Mediterranean, Southeast Asia, parts of Asia and Latin America. To get an idea of the incidence in different states in the past, below are some examples of cases per 100,000 population: in China in 2009 of 2.7, in Greece in 2007-2012 of 1.43, In Italy in 2005 of 1.40, In Mexico in 2000 of 25.69, in Iran in 2008 of 43.2, and in Saudi Arabia in 2018 of 16.3.
Humans can contract the disease by coming into contact with infected animals or animal products.
There are three routes of infection:
- through contaminated food or drink;
- through inhalation;
- through small wounds on the skin.
Of these, however, surely the first is the most common route; in fact, the brucellosis bacterium is also present in the milk of infected animals: consumption of fresh milk from infected animals that has not undergone proper heat treatment, and of fresh or ripened cheese less than 72 days and prepared from infected unpasteurized milk is the main route of transmission.
The second route of infection, that by inhalation, is mainly occupational and relates to those who work in close contact with animals or hunters.
The second route of transmission is by inhalation.
Finally, human-to-human infection is extremely rare; although very rare, however, mother-to-child transmission through breast milk is possible. Then, cases of transmission by sexual route or from tissue transplantation have also been reported.
Diagnosis of brucellosis in humans is based on history (occupation, contact with animals, travel to endemic areas, ingestion of high-risk foods), symptomatology, and serologic test results. Definitive diagnosis is made by blood cultures, PCR, and bone marrow or other tissue cultures.
The main symptoms are entirely nonspecific:
.- wavy fever, i.e., characterized by moments of elevated temperature and moments of normal temperature within the same day, is more specific to the disease;
- high fever (in the acute form);
- widespread arthralgias;
- profuse sweating (especially at night);
- increased volume of the liver and spleen;
- dangerous central nervous system infections can also occur, and in some cases there is chronicity, characterized by recurrent fevers, fatigue states, and joint pain.
In the most severe cases, hospitalization may be necessary.
Even so, there is still a risk of mortality fortunately less than 2%.
Treatment is antibiotic and is continued for at least 6 weeks to avoid relapse.
As for prevention, to date there is still no vaccine for humans, and it is therefore essential to be aware of the epidemiological data of the areas where you want to go in order to pay more attention to the most important form of prevention, which is not to consume unpasteurized products!
Sources:
- Epicenter.iss.it
- Health.gov.it
- Reem AL JIndan, Saudi J Biol Sci. 2021 Jan; 28(1): 272-279.
- Skalsky K, Yahav D, Bishara J, Pitlik S, Leibovici L, Paul M. Treatment of human brucellosis: systematic review and meta-analysis of randomized controlled trials. BMJ 2008: 336: 701- 704.
- Gul, S., Khan, A.J.P.v.j., 2007. Epidemiology and epizootology of brucellosis: A review, 27(3), p. 145 .
- Li Z. Molecular characteristics of Brucella isolates collected from humans in Hainan Province, China. Front. Microbiol. 2020;11:452.
