It is vital that all imported cattle are tested after calving even if that calving is normal. Current regulations require all cattle that have had contact with infected animals to be slaughtered. This means that if imported cattle, which are subsequently found to have brucellosis, are mixed with the main herd before they calve, the cattle they have been mixed with will have to be slaughtered as well. It is therefore essential to ensure that imported animals are properly quarantined until they have tested negative for brucellosis after calving in the herd for the first time.
Work out a proper biosecurity with your vet before you bring the cattle on-farm. Brucellosis has been effectively controlled by a statutory testing programme to identify infected cattle.
This has changed brucellosis from a very common cause of abortion to a very rare disease. However, as the recent cases show the farming industry needs to be vigilant to prevent it from becoming a major problem once again.
B abortus can be recovered from the placenta but more conveniently in pure culture from the stomach and lungs of an aborted fetus. Most cows cease shedding organisms from the genital tract when uterine involution is complete. Foci of infection remain in some parts of the reticuloendothelial system, especially supramammary lymph nodes, and in the udder. Udder secretions are the preferred specimens for culture from a live cow. Serum agglutination tests have been the standard diagnostic method.
Agglutination tests may also detect antibodies in milk, whey, and semen. When the standard plate or tube serum agglutination test is used, complete agglutination at dilutions of or more in serum samples of nonvaccinated animals, and of of animals vaccinated at 4—12 mo of age, are considered positive, and the animals are classified as reactors. Other tests that may be used are complement fixation, rivanol precipitation, and acidified antigen procedures.
In official eradication programs on an area basis, the Brucella milk ring test BRT has effectively located infected dairy herds, but there are many false-positive tests. The brucellosis status of dairy herds in any area can be monitored by implementing the BRT at 3- to 4-mo intervals. Milk samples from individual herds are collected at the farm or milk processing plant. Cows in herds with a positive BRT are individually blood tested, and seropositive cows are slaughtered to determine herd status.
Nondairy and dairy herds in an area may also be screened for brucellosis by testing serum samples collected from cattle destined for slaughter or replacements through intermediate and terminal markets, or at abattoirs.
Reactors are traced to the herd of origin, and the herd is tested. The cost of identifying reactors by this method is minimal compared with that of testing cattle in all herds. Screening tests, including the brucellosis card or rose bengal test and plate test, may be used in markets and laboratories to identify presumptively infected animals, thus reducing the number of more expensive and laborious diagnostic tests. Brucellosis-free areas can be achieved and maintained, effectively and economically, by using the BRT on dairy herds and through market cattle testing.
Adult cattle are sampled at the time of slaughter. Supplemental tests using sensitive screening methods may be used in cattle in which the brucellosis status is unclear. Use of a battery of these tests improves the probability of detecting infected cattle that have remained in some herds as possible reservoirs of infection.
Supplemental tests are also used to clarify the results of plate or card tests, especially in serum samples from vaccinated cattle. These tests, which include complement fixation and rivanol precipitation, are designed to detect primarily the antibodies specifically associated with Brucella infection. Additionally, the residual PCR inhibition by complex matrices can also be overcome through the use of proper internal amplification control [ 89 ].
The circulating macrophages engulf and processes bacteria and negatively affect the PCR-based detection. However, the modern PCR method has the ability to detect even the non-viable or phagocytosed microorganisms [ 91 ]. Brucella DNA has also been successfully detected in milk samples from an infected animal using PCR-based assay [ 92 ].
Various gene and loci have been identified as potential targets for PCR-based amplification [ 50 , 93 ]. For example, IS insertion element is a potential target that can be used for the detection of traceable bacteria as its multiple copies are found in the Brucella chromosomes [ 94 ].
Moreover, 16S rRNA also serves as a potential target, not only for Brucella but also related microorganisms [ 95 ]. The species-specific real-time PCR and conventional Bruce-ladder PCR assays are also considered to be key tools, used for confirmation and delineation of Brucella species [ 96 ]. For the diagnosis of human brucellosis, multilocus variable number tandem repeat analysis 16 loci panel MLVA is considered to be an authentic target [ 97 ].
Summarizing the facts, molecular diagnostics have the edge over conventional methods as they are robust and versatile, and due to the non-infectious nature of DNA, therefore safer for laboratory personnel. PCR-based detection is also more reliable and specific when compared to the serum plate agglutination test SPAT [ 98 , 99 ]. However, for a PCR-based assay, a specialized machine like a conventional thermocycler or real-time PCR is required along with skilled personnel.
Moreover, specific primers for each Brucella species will be required. Though the complex nature of brucellosis makes it harder to treat, long-term treatment with an antibiotic is thought to be beneficial. In most cases, antibiotics in combination are found to be more effective against the infection; however, the state of the disease still does not lose its importance [ , ]. Several conventional antibiotics including tetracycline, trimethoprim-sulfamethoxazole, aminoglycosides, rifampicin, quinolones, chloramphenicol, doxycycline, and streptomycin are commonly used in clinics [ , ].
In several cases, the application of antibiotics in a specific order has given best results. Likewise, a case reported that treatment with doxycycline for six months, followed by streptomycin for three weeks was found very effective against brucellosis in human [ ].
Another study reported that the alkaloid columbamine in combination with jatrorrhizine were more effective against brucellosis caused by B. The World Health Organization recommends that acute brucellosis cases be treated with oral doxycycline and rifampicin mg for six weeks [ ]. However, rifampicin monotherapy is in common practice for treating brucellosis in pregnant women, and a combined therapy of sulphamethoxazole and trimethoprim is recommended for children [ ].
In underdeveloped countries, treatment of cattle is not a common practice; however, the infected animals are isolated, culled or slaughtered to prevent the spreading of infection to other herd and at substantial veterinary costs. In China, a case of subdural empyema complicated by intracerebral abscess due to Brucella infection was effectively treated with antibiotic therapy ceftriaxone, doxycycline, rifapentine [ ].
In line with this, several reports suggested the combination therapy of doxycycline and rifampicin for six weeks is enough to eradicate Brucella infection, as well as associated complications [ 46 , , , ].
This combination of doxycycline and rifampicin has also been proven experimentally [ ]. As a result of continued efforts by the scientific community to develop an effective therapeutics, Caryopteris mongolica Bunge Lamiaceae has been tested in combination with doxycycline [ , ].
Despite the fact that several therapeutics are in practice which makes the disease manageable, an effective therapeutic is required for the complete treatment of brucellosis. To overcome the widespread intra- and inter-species infection of brucellosis, potent vaccination would be the best strategy [ ].
Currently, several vaccines including S19, RB51, B. In cattle, B. S19 is used to vaccinate young female calves 3 to 12 months ; however, it is not recommended for pregnant cattle, as it results in abortion [ ]. S19 was found more effective in developing long-term immunity, when compared with RB51, in young calves [ , , ]. However, RB51 does not interfere with serological diagnosis [ , ].
S19 and RB51 are live attenuated vaccines derived from B. A cocktail lysate of S19 and RB51 was also tested as an immune-therapy to treat the bracelet infected cattle [ ]. DNA vaccines have also been tested and show promising results when compared with S19 and RB51; however, several boosters were required to achieve the desired immunity [ , ]. In China, the S2 vaccine is widely in practice; however, it triggers an innate immune response and causes increased inflammation [ ].
In conclusion, no effective and relatively safe vaccine is available that provides long-term protection against brucellosis. An effective approach should be adopted to eradicate and prevent brucellosis in cattle and humans. Vaccination is an effective strategy to prevent the spread of brucellosis and is in practice worldwide. However, there is demand for the development of new vaccines that are safer and more effective [ 9 ]. To cover the zoonotic aspects of brucellosis, proper education of field farmers, field workers, and the local community in endemic regions is required.
The effective pasteurization of milk and other products and disinfection of meat is of key importance before consumption. The regular sterilization of labwares and laboratory tools would also result in a decrease in infection of clinical laboratory personnel [ ]. Apart from local efforts, an effective global policy is required for the complete eradication of brucellosis. Proper veterinary legislation must be implemented and policies regarding animal health need to be encouraged.
Modern updated knowledge on brucellosis should be delivered to farmers, veterinary professionals, and health educators, especially for rural populations, which will help to prevail over the dispersal of Brucella infection [ , ]. Brucellosis is not only a threat to livestock but also a global public health issue. Unfortunately, we lack not only a proper treatment but also a reliable diagnosis.
Adequate and timely diagnosis of brucellosis is necessary to control and treat the disease in the best way. Different serological and molecular methods are used for the screening of the disease. However, each test has some drawbacks in one way or another. So here we suggest that due to the zoonotic importance of the Brucella infection, it is necessary to handle the disease in a proper way and a combination of particular tests should be used to screen for brucellosis in both humans and animals.
The different cited studies regarding brucellosis in humans and cattle revealed that the combination of both the molecular and serological methods must be practiced for accurate diagnosis.
If the infected animals are in chronic infected condition, they should be culled to prevent the disease spreading. The formal education and necessary training of farmers, especially those living in rural areas, would also help to get control over the disease.
With rising interest of the scientific community in brucellosis, a significant improvement in diagnosis and treatment is expected. We are also in need of a broad-spectrum vaccine against Brucella for complete eradication of the disease worldwide.
National Center for Biotechnology Information , U. Trop Med Infect Dis. Published online Jun Author information Article notes Copyright and License information Disclaimer. Received Apr 28; Accepted Jun 9. This article has been cited by other articles in PMC. Abstract Brucellosis is one of the most common contagious and communicable zoonotic diseases with high rates of morbidity and lifetime sterility.
Keywords: brucellosis, cattle, human, serological and molecular methods. Introduction Brucellosis is thought to have been identified in the late Roman era, named because of its resemblance to the organism Brucellae later called Brucella from carbonized cheese. Open in a separate window. Figure 1. Summarizing the impact of Brucella infection in humans as well in cattle. Brucella: The Causative Agent of Brucellosis Brucellosis is caused by Brucella , a Gram-negative, aerobic, and facultative intracellular coccobacillus [ 16 ].
Brucellosis Transmission The infection of Brucella species is commonly mediated by direct contact with the placenta, fetus, fetal fluids, and vaginal discharges or byproducts e. Global Public Health Concerns Brucellosis has been reported in 86 different countries worldwide and is a serious threat not only to livestock but also to human health globally.
Clinical Picture of Brucellosis in Cattle Brucellosis is a widespread reproductive disease, commonly causing abortion, death of young ones, stillbirth, retained placenta or birth of weak calves, delayed calving, male infertility, and marked reduction in milk yield [ 37 , 58 , 59 , 60 ].
Human Brucellosis Human brucellosis is known by many different names such as Malta fever, Cyprus or Mediterranean fever, intermittent typhoid, rock fever of Gibraltar, and more commonly, undulant fever [ 61 ]. Diagnosis of Brucellosis 2. Serological Tests At the moment, no specific diagnostic test is available to identify Brucella. Molecular Diagnosis Polymerase chain reaction PCR -based diagnosis has been adopted in recent decades and is rapidly replacing conventional assays for diagnosis in clinical laboratories.
Treatment of Brucellosis Though the complex nature of brucellosis makes it harder to treat, long-term treatment with an antibiotic is thought to be beneficial.
Vaccination against Brucellosis To overcome the widespread intra- and inter-species infection of brucellosis, potent vaccination would be the best strategy [ ].
Control Strategies for Prevention of Brucellosis An effective approach should be adopted to eradicate and prevent brucellosis in cattle and humans. Conclusions Brucellosis is not only a threat to livestock but also a global public health issue.
Author Contributions M. Conflicts of Interest The authors declare no conflict of interest. References 1. Cutler S. Brucellosis—New aspects of an old disease. Christopher S. Brucellosis: Review on the recent trends in pathogenicity and laboratory diagnosis. Johansen M. Control of neglected zoonotic diseases.
Acta Trop. Olsen S. Advancement of knowledge of Brucella over the past 50 years. Byndloss M. Brucella spp. Virulence factors and immunity. Von Bargen K. Internal affairs: Investigating the Brucella intracellular lifestyle.
FEMS Microbiol. Pappas G. The new global map of human brucellosis. Lancet Infect. Foster J. African lineage Brucella melitensis isolates from Omani livestock. Wernery U. Camelid brucellosis: A review. Narnaware S. Pathological and diagnostic investigations of abortions and neonatal mortality associated with natural infection of Brucella abortus in dromedary camels.
Garcell H. Outbreaks of brucellosis related to the consumption of unpasteurized camel milk. Public Health. Gwida M. Brucellosis in camels. Comparison of diagnostic tests for the detection of Brucella spp. BMC Res. Rushton J. Brucella canis - affects dogs, causing canine brucellosis.
The Brucella diseases occur throughout the world and, excepting ovine brucellosis, are zoonotic, that is they can be spread from animals to humans.
Brucellosis in humans caused by Brucella abortus was known as undulant fever in Australia, before this disease was eradicated. It is an occupational disease of people who work with animals, such as veterinarians, farmers and abattoir personnel.
In animals the Brucella bacteria localise and multiply in the reproductive organs. In males this often results in reduced fertility. Pregnant females can suffer abortion, stillbirth or early death of the offspring when the uterus becomes infected. The disease can spread to other animals if they eat infected afterbirth, fluids or any contaminated feed. Brucella bacteria can also localise in mammary glands, infecting milk and in limb joints causing arthritis. Brucellosis in Cattle Bovine brucellosis or contagious abortion causes mass abortion in cattle herds.
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