Brucellosis PDF

BRUCELLOSIS By Prof. Ameer kadhim Hussein M.B.Ch.B. FICMS (Community Medicine)  OBJECTIVES Describe and discuss the epidemiology, mode of transmission of Brucellosis.  Describe and discuss preventive, Epidemic and international measures to control Brucellosis ...

BRUCELLOSIS By Prof. Ameer kadhim Hussein M.B.Ch.B. FICMS (Community Medicine)  OBJECTIVES Describe and discuss the epidemiology, mode of transmission of Brucellosis.  Describe and discuss preventive, Epidemic and international measures to control Brucellosis  IDENTIFICATION Brucellosis is a bacterial disease caused by small, gram negative rod shaped, non motile, non sporing and intracellar coccobacilli of genus Brucella. It is a zoonotic disease meaning that it is primarily an infection of animals but can be transmitted to human. Different species of Brucella bacteria mostly infect domestic livestock including: 1. Cattle (B. abortus). 2. Sheep and goats (B. melitensis). 3. Pigs (B.suis). 4. Dogs which can also be infected with (B. canis). 5. Brucella ceti and Brucella pinnipedialis Other names of brucellosis: (Undulant fever, Malta fever and Mediterranean fever). BRUCELLOSIS  Pathogenicity  Brucella melitensis (from sheep; highest pathogenicity)  Brucella suis (from pigs; high pathogenicity)  Brucella abortus (from cattle; moderate pathogenicity)  Brucella canis (from dogs; moderate pathogenicity)   GEOGRAPHICAL DISTRIBUTION It is a worldwide infection traditionally associated with farm workers, veterinarians and persons whose occupation includes packing of meat or dairy products. It affects people of all age groups and of both sexes. Although there has been great progress in controlling the disease in many countries, there still remain regions where the infection persists in domestic animals and transmission to the human population frequently occurs.  GEOGRAPHICAL DISTRIBUTION It is an important human disease in many parts of the world especially in the Mediterranean countries of Europe, Africa, the Middle East, south and central Asia and central and south America and Mexico and yet it is often there are only a few countries in the world that are officially free of the disease although cases still occur in people returning from endemic countries. Significant proportion of brucellosis cases still remain undiagnosed. The disease is now rare in most European countries, North America and Australia. BRUCELLOSIS  AGE-RELATED DEMOGRAPHICS Brucellosis in the Mediterranean, chiefly due to B melitensis, has the highest age/sex-related incidence in males in their mid- 20s. A report from northern Saudi Arabia found that 60% of cases of brucellosis occurred in individuals aged 13-40 years, whereas 21% occurred in those younger than 13 years, 16% in those aged 40-60 years, and 2.5% in those older than 60 years. For unknown reasons, men aged 13-40 years are particularly vulnerable to the manifestation of illness due to B melitensis. Possible explanations include engaging in activities that increase exposure to Brucella organisms (eg, animal husbandry) and less diligent personal hygiene. AGE-RELATED DEMOGRAPHICS  The predilection is not universal, given that 60% of cases in Jordan occur in individuals younger than 24 years.  Elderly individuals with acute localized brucellosis are particularly likely to manifest destructive localized brucellosis of the spine.  Brucellosis is generally uncommon in infants. The international literature suggests that brucellosis may be more common in children in developing countries because of lack of pasteurization and working in an agrarian society. Transmission to infants may occur through breastfeeding or ingestion of raw milk.  SEX-RELATED DEMOGRAPHICS Worldwide, brucellosis is more common in males than in females. Young adult males predominate in most series of patients with brucellosis compiled in areas of endemic disease. A report from northern Saudi Arabia found a male-to-female ratio of 1.7:1, chiefly individuals aged 13-40 years. The cases represented in such series are caused chiefly by B melitensis. Occupational exposure to animals likely plays an important role in the enhanced vulnerability of men to the development of brucellosis. Food-borne brucellosis is not limited according to age or sex and is found in women and men in equal numbers.  CLINICAL MANIFESTATION Fever, Night sweats, Malaise, Anorexia, Arthralgia, Fatigue, weight loss and depression. Subclinical has been reported. Bone and joint involvement are the most frequent complications of brucellosis occurring in up to 20-60% of cases. Different syndromes have been reported including sacroiliitis, spondylitis, peripheral arthritis, osteomyelitis, bursitis and tenosynovitis. Brucella sacro-iliitis is especially common. Patients present with fever and back pain often radiating down the legs (sciatica). Genito urinary involvement occur in 2% to 20% of cases with orchitis and epididymitis as a common manifestations Neuro-brucellosis is less common but more severe (represent 3- 7%). Recovery is usual but disability is often pronounced. Case fatality rate in untreated cases represent 2% or less usually from endocarditis. In brucellosis relapse can occur.  MODE OF TRANSMISSION Brucellosis is a zoonotic disease transmitted to humans by: 1. Contact through mucus membranes and breaks in the skin with fluids from infected animals (including sheep, cattle, goats, pigs, or other animals) these fluids include blood, urine, vaginal discharges and aborted fetuses and especially placentas. 2. Ingestion of raw milk and dairy products such as unpasteurized milk and cheese and ingestion of undercooked meat from infected animals. 3. Airborne transmission has been reported in laboratory and slaughterhouse workers. 4. Accidenital self inoculation of strain 19, REV-1 and RB 51 brucella animal vaccines. 5. Person to person transmission is rare, possible sexual transmission and breast feeding women may transmit infection to their infants.  BRUCELLOSIS Reservoir Cattle, swine, goats and sheep. Dog is regard a reservoir for B. canis. Incubation period Highly variable. Usually 1-3 weeks, but may be as long as 6 months or more. Period of communicability Rare person to person transmission but risk may exist for medical personnel in endemic area expose to contaminated fomities, tissues or massive bleeding such as obstetric procedures.  BRUCELLOSIS Susceptibility Severity and duration of clinical illness vary. Duration of acquired immunity is uncertain. Diagnosis by the following: 1.Isolation of the infectious agent from blood, bone marrow or other tissues or discharges. 2. PCR. 3. Serological tests which allow precise diagnosis in about 95% of cases (including combination of Rose Bengal and seroaglutination test with coombs-test and ELISA- test).  CASE SCENARIO 81-year-old man, functionally able to walk with minimal assistance and had mild cognitive impairment who presented with high-grade fever with chills, anorexia, low back pain and arthralgia for 10 days. The above complaints occurred often for 1 month and had fever intermittently. Lab investigations revealed as high CRP 117 mg/l, low Hb 9.1 g/dl and mild elevation in liver enzymes with normal leukocyte and platelet count. His blood culture positive for Brucella melitensis with high brucella Antibody titter 1:1280. The diagnosis made as Brucellosis.  METHODS OF CONTROL The most effective method for preventing human brucellosis is control and eradication of infections in animal reservoirs. a. Preventive measures : 1.Educate the public especially the tourists about the risks associated with drinking unpasteurized milk or eating products made from unpasteurized milk. 2.Educate farmers and workers in slaughter houses and butcher shops about the nature of disease and risk of handling carcasses and product from infected animals and importance of appropriate ventilation. 3.Educate hunters to use protective gloves and clothing when handling feral swine or potentially infected wildlife such as elk.  METHODS OF CONTROL 4. Search for infection among livestock by serological testing and by ELISA or ring test and eliminate infected animals by segregation and or slaughtering. In high prevalence area immunize young goats and sheep with live attenuated Rev-1 strain of B. melitensis and immunize calves and adult animals with strain 19 (B. abortus) vaccine. Since 1996 the strain RB51 of B. abortus has replaced strain 19 for immunization of cattle against B. abortus. RB51 vaccine was designed to be less virulent for humans than strain 19 when accidentally injected.  METHODS OF CONTROL 5. Pasteurize milk and dairy products from cows, sheep and goats. Boiling milk is applied when pasteurization is impossible. Don’t eat meat from animals that appear ill. 6. Exercise care in handling and disposal of placenta and discharges and fetuses and disinfect contaminated areas. (REV-1) AND STRAIN 19 VACCINES  Methods of control b. Control of patient , contacts and immediate environment 1. Report to local health authority. 2. Isolation: draining and secretion precautions applied if there are draining lesions, otherwise none. 3. Concurrent disinfection of purulent discharges. 4. Investigation of contacts and source of infection: Trace infection to the common or individual source usually infected domestic goats, swine and cattle or raw milk or dairy products from cows and goats. Test for suspected animals and remove reactors.  METHODS OF CONTROL  For acute brucellosis in adults and children older than 8 years, the World Health Organization (WHO) guidelines recommend the following:  Doxycycline 100 mg PO twice daily plus rifampin 600-900 mg/day PO – Both drugs are to be given for 6 weeks; this regimen is more convenient but probably increases the risk of relapse  Doxycycline 100 mg PO twice daily for 6 weeks and streptomycin 1 g/day IM for 2-3 weeks – This regimen is believed to be more effective, mainly in preventing relapse; gentamicin can be used as a substitute for streptomycin and has shown equal efficacy  Ciprofloxacin-based regimens have shown efficacy equal to that of doxycycline-based regimens Epidemic and international measures Epidemic measures Search for common vehicle of infection usually raw milk or milk products especially cheese from infected herd. Stop production and distribution of product unless pasteurization is instituted. International measures: Control of domestic animals and animal products in international trade and transport.  SUMMARY  Brucellosis is found globally and is a reportable disease in most countries.  The disease causes flu-like symptoms, including fever, weakness, malaise and weight loss.  Person-to-person transmission is rare.  Brucellosis is a bacterial disease caused by various Brucella species, which mainly infect cattle, swine, goats, sheep and dogs. Thank you