Brucellosis: Epizootiologic and diagnostic challenge

Abstract

Although it has been known as a separate etiological entity for almost 150 years, brucellosis is, on a global scale, one of the most frequent diseases that is transferred from animals to humans. It is present as an endemic disease in almost all countries of the Mediterranean Sea, which indicates that a large number of aspects in connection with the control and epizootiology of this disease still remain unexplained. Three of the six types of brucella have been officially confirmed in our country as well. They are Brucella melitensis biotip 3, Brucella suis biotip 2 and Brucella canis. Brucellosis is endemically present in Kosovo and Metohija province and in southern Serbia proper; over the past few years, the spread of brucellosis in sheep and goats as primary hosts for B. melitensis to new territories, mostly in Vojvodina province, has shown that risk analysis is one of the main factors in selecting and implementing control programmes. A correctly selected set of diagnostic tests yields reliable data in most cases, but interpretations of results are prone to result in subjective assessments as well. A special problem in the serological diagnosis of brucellosis is the cross reactivity of brucellas and some other bacteria, often a weak immunological response of the animal, or that the type of brucella that causes the infection determines the sensitivity and specificity of the applied tests, most often screenings tests. Due to the big economic losses resulting from disease control and eradication, and the serious risk to human health, brucellosis still poses an epizootiological, and, in particular, a diagnostic challenge.

Mada poznata kao izdvojen etiološki entitet već skoro sto pedeset godina, Bruceloza je u svetskim razmerama jedna od najčešćih bolesti koje se sa životinja prenose na ljude. Endemski je prisutna u skoro svim zemljama Mediterana, što pokazuje da je veliki broj aspekata vezanih za kontrolu i epizootiologiju ove bolesti ostao još uvek nerazjašnjen. Od šest vrsta brucela, nedavno su tri zvanično potvrđene i u našoj zemlji. To su Brucella melitensis biotip 3, Brucella suis biotip 2 i Brucella canis. Bruceloza je endemski prisutna na Kosovu i Metohiji i jugu Srbije. Poslednjih nekoliko godina je širenje bruceloze ovaca i koza kao primarnih domaćina za B. melitensis na nove teritorije, uglavnom u Vojvodini, pokazalo da je analiza rizika osnov u odabiru i sprovođenju kontrolnih programa. Pravilno izabran set dijagnostičkih testova u najvećem broju slučajeva daje pouzdane podatke, ali su tumačenja rezultata podložna i subjektivnoj proceni. Poseban problem u serološkoj dijagnostici bruceloze predstavlja unakrsna reaktivnost brucela i nekih drugih bakterija, često slab imunski odgovor inficirane životinje, kao i kvalitet upotrebljenih testova. Najnovija istraživanja ukazuju da od vrste životinje, odnosno vrste brucele koja izaziva infekciju zavisi osetljivosti specifičnost primenjenih, najčešće screening testova. Zbog velikih ekonomskih gubitaka u kontroli i eradikaciji bolesti i ozbiljnog rizika za zdravlje ljudi, bruceloza i dalje predstavlja epizootiološki, a posebno dijagnostički izazov.