Epidemiologistsundertake the duty of researching disease outbreaks. Understandingthe causative agent and transmission process of diseases are crucialin developing treatment drug or preventative measures (Aparicio,2013). The essay will discuss a disease outbreak case in Montanafarm.
The disease seemed to affect both the farm workers and cattle.
The farm workerscomplained of severe fever, headache, back pain, abdominal pain,aches and pains all over the body, cough, night sweats and weakness.The farm manager informed me that two of the pregnant heifers hadaborted. On examining the bull, I noticed the testicles were swollen.Furthermore, the membranes of the cattle showed signs of infections(inflammation). Consequently, I took fluid and biopsies of the animal(Aparicio, 2013).
Upon thelaboratory examination of the milk, urine, feces, blood, placentafluid and bone marrow biopsy. I determined the causative agent to beBrucella abortus (Aparicio, 2013).
HowI Identified the Agent
I carried outblood cultures using Constaneda medium. I made frequent examinationsto assess whether there was any growth. Close to six weeks, therewas no growth at all. On the sixth week, I noticed tiny rod-shapedcolonies on the plate. I isolated the organism and carried out amicroscopic examination and biochemical tests. The gram stain on theisolate was positive. Furthermore, the isolate was positive foroxidase and catalase biochemical tests. On further analysis of itsgrowth demand, I determined that the strain required carbon dioxide.The tests for the growth in fushin were positive while in thionin itwas negative. The test for production of hydrogen sulfide duringgrowth was positive. I carried out, serological tests such asagglutination which was positive. I also carried outenzyme-linked-immunosorbent assays (ELISA), to improve thesensitivity and specificity of my tests. All my tests on ELISA werepositive (Aparicio,2013). At this point, I felt confident I haveestablished the causative agent of the disease. Further tests thatmay be used include polymerase chain reaction (PCR), the method isvery specific for Brucella strains (Aparicio, 2013).
The possibleroute of infection could be the feeds given to the cattle werecontaminated with Brucella. It is also possible that one of the cowswas not vaccinated against the disease. The bulls may have acquiredthe disease by licking the genitals of the cows. A possibility alsoexists, the disease was carried by the bull and was brought to thecows through venereal transmission, and open wounds on the skin mayhave enabled penetration of Brucella into the cow (Aparicio, 2013).
Originof the Disease
The disease isendemic in Kazakhstan (Aparicio,2013). Most countries in the CentralAsia including China, Mongolia are at risks of an epidemic. Theincidences of the disease in the rest of the world are low.
Brucellosis doesnot have an effective antibiotic to treat it, but there is a vaccinefor calves. Therefore, calves should be vaccinated against thedisease. The farmer needs to use the artificial insemination toreduce risks of venereal infection by the bull. The feeds should bescreened for Brucella. The farm workers need to be treated. Milk orany other animal product should be cooked adequately (Aparicio,2013).
In conclusion,Brucellosis is a disease that can be transmitted from animals tohuman (zoonotic). The symptoms of the disease are severe in thehumans and mild in animals. Brucella exists in many strains. However,the type that affects cattle is called Brucella abortus. Thebacteria grow slowly in standard culture and are gram-positive.
Aparicio, E. D. (2013). Epidemiology of brucellosis in domesticanimals caused by Brucella melitensis, Brucella suis and Brucellaabortus. Rev sci tech Off int Epiz, 32(1),53-60.
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