zoonoses and communicable diseases common to ... - PAHO/WHO

44 BACTERIOSESthe disease can vary from a few weeks or months to several years. Modern therapyhas considerably reduced the disease’s duration as well as the incidence of relapses.At times, it produces serious complications, such as encephalitis, meningitis, peripheralneuritis, spondylitis, suppurative arthritis, vegetative endocarditis, orchitis, seminalvesiculitis, and prostatitis. A chronic form of the disease occurs in some patientsand may last many years, with or without the presence of localized foci of infection.The symptoms are associated with hypersensitivity. Diagnosis of chronic brucellosisis difficult.Separate mention should be made of human infection caused by the B. abortusstrain 19 vaccine, which is the vaccine used most often to protect cattle. Cases havebeen described of accidents among those administering the vaccine (veterinariansand assistants) who have pricked a finger or hand with the syringe needle or havegotten aerosol in their eyes. If someone has no prior exposure to brucellae and hasno antibodies to the agent, the disease sets in abruptly after a period of 8 to 30 days.The course of the disease is usually shorter and more benign than that caused by thefield strains of B. abortus, but there are severe cases that require hospitalization. Inindividuals who have been exposed to brucellae, as is usually the case with veterinariansand vaccinators, a different, allergic-type syndrome appears that is characterizedby painful swelling at the inoculation site. After some hours, the patient mayexperience systemic symptoms similar to those described in individuals infected bystrain 19 without prior exposure. The symptoms usually abate in a few days with orwithout treatment. Local and general symptoms may recur if the person has anotheraccident (Young, 1989). Considering the millions of doses of strain 19 vaccine usedeach year throughout the world, the rate of incidence of the disease due to this strainis insignificant.Another strain that is used to vaccinate small ruminants, B. melitensis Rev. 1, canalso infect the vaccinator. Under the aegis of the World Health Organization (WHO)and its collaborative centers, Rev. 1 vaccine was administered to 6 million animalsin Mongolia between 1974 and 1977. Six trained vaccinators inoculated themselvesaccidentally; four of them showed clinical symptoms but recovered after immediatehospital treatment.There are many infections that occur asymptomatically in areas with enzooticbrucellosis, particularly the bovine form.The recommended treatment for acute brucellosis is a daily dose of 600 mg to 900mg of rifampicin, combined with 200 mg per day of doxycycline for at least sixweeks. Relapses are very rare with this treatment. If there is a Jarisch-Herxheimerreaction upon starting antibiotic treatment, intravenous administration of cortisol isrecommended. Sometimes various series of treatment are needed. If antibiotic therapyis not successful, a chronic focus of infection should be sought, particularly ininfections caused by B. melitensis and B. suis (WHO, 1986). In the event of arelapse, the treatment indicated above should be restarted. Steroids may be administeredto counteract toxicity in patients who are very ill (Benenson, 1992).The Disease in Animals: The principal symptom in all animal species is abortionor premature expulsion of the fetus.CATTLE: The main pathogen is B. abortus. Biovar 1 is universal and predominantamong the seven that occur in the world. The distribution of the different biovarsvaries geographically. In Latin America, biovars 1, 2, 3, 4, and 6 have been con-