3 Resistance of brucella Heating at 60CFor 10 minutes Phenol
1%For 15 minutes Direct sunlightIn a few hours MilkFor several days
Fresh cheeseFor 3 months Tap-waterFor 57 days Human urineFor 1 week
DustFor 6 weeks Damp soilFor 10 weeks Animal fecesFor 100 days
Slide 4
SpeciesBiovar/Ser ovar Natural HostHuman Pathogen B.
abortus1-6, 9cattleyes B.melitensis1-3goats, sheepyes B. suis1,
3swineyes 2haresyes 4reindeer, caribouyes 5rodentsyes B.
canisnonedogs, other canids yes B. ovisnonesheepno B.
neotomaenoneDesert wood ratno B. maris (?)marine mammals?
Slide 5
5 Occurrence in Wildlife
Slide 6
6 SpeciesBiotypes Br. Abortus1,2,3,4,5,6,8,9 Br. Melitensis12
Br. Suis12 Br. CanisNot found Isolated species in Iran
Slide 7
The Many Names of Brucellosis Human Disease Malta Fever
Undulant Fever Mediterranean Fever Rock Fever of Gibraltar Gastric
Fever Animal Disease Bangs Disease Enzootic Abortion Epizootic
Abortion Slinking of Calves Ram Epididymitis Contagious Abortion
7
Slide 8
Transmission to Humans Conjunctiva or broken skin contacting
infected tissues Blood, urine, vaginal discharges, aborted fetuses,
placentas, Sexual,Blood transfusion,Organ transplant Ingestion Raw
milk & unpasteurized dairy products Rarely through undercooked
meat 8
Slide 9
Transmission to Humans Inoculation with vaccines B. abortus
strain 19, RB-51 B. melitensis Rev-1 Conjunctival splashes,
injection Incubation varies 5-21 days to three months 9
Slide 10
10 Skin abrasion, conjunctivae, inhalation or ingestion
Engulfed by neutrophils and monocytes (resistant to killing)
Localize regional lymph nodes Infect phagocytic cells in the RE
system and form granulomas Pathogenesis
Slide 11
11 Occurs worldwide Endemic areas - Africa, Asia True incidence
not known
Slide 12
Who is at Risk? Occupational Disease Cattle ranchers/dairy
farmers Veterinarians Abattoir workers Meat inspectors Lab workers
Hunters Travelers Consumers of unpasteurized dairy products 12
Slide 13
13 Effect of Gender Men aged 15-45 years are affected twice as
often as women of the same age Male predominance seem to be a
factor in some cases The man is more likely than the woman to be
exposed to the heaviest concentration of organisms
Slide 14
14 Effect of Gender In Iran both sexes are nearly always
equally contacted with contaminated animals and dairy products
There is not a significant predominance of male to female
brucellosis in Iran
Slide 15
Sex distribution in Iran 15 Male 56% Female 44%
Slide 16
16 Age distribution Children are affected very much less than
adults The odd low incidence in children is unexplained It may be
that gastric acidity is less often deficient than in adult
Occupational exposure is much more important
B. abortus Worldwide Some countries have eradicated it
Notifiable disease in many countries abortions, arthritic joints.
Fever of Unknown Origin (FUO) ( ( Contagious/ Infectious
abortion)
Slide 20
B. canis Poorly understood 1-19% prevalence in United States
contact with aborted fetuses and semen. Rarely causes disease in
humans. 20
Slide 21
B. suis Biovars 1 and 3 Worldwide problem. Free United Kingdom,
Canada Eradicated Holland, Denmark Low Incidence Middle East, North
Africa 21
Slide 22
Human Disease Can affect any organ or system All patients have
a cyclical fever Headache, weakness, arthralgia, depression, weight
loss, fatigue, liver dysfunction 22
Slide 23
Clinical manifestation Triad: Fever, Arthralgia / Arthritis,
Hepatosplenomegaly +ve History of animal or food exposure 23
Diagnosis History of animal contact is pivotal In endemic area,
it should be in the DDx of any nonspecific febrile illness 32
Slide 33
33 Laboratory changes Serologic Tests Tube Agglutination 2ME
Agglutination Coombs test Complement fixation Radioimmunoassay
ELISA Rapid Agglutination Rose bengal test
Slide 34
Laboratory changes Serologic Tests STA 2ME COOMBS C.F. RIS
ELISA IgM + IgG IgG 1) If STA is negative and disease is chronic
then only IgG 2) If STA is positive, IgM + IgG IgG IgG & IgM
separately 34 Tests Antibodies which can be detected
Slide 35
Diagnosis in Humans Isolation of organism Blood, bone marrow,
other tissues Serum agglutination test Four-fold or greater rise in
titer Samples 2 weeks apart Immunofluorescence Organism in clinical
specimens PCR 35
Slide 36
Laboratory WBC (N) or. Monocytosis ESR of little help Blood
cultures slow growth = 4 weeks new automated system BATEC
identifies he organism 4-8 days more recent (BACT/ALERT) - 2.8 days
36
Slide 37
37 Laboratory changes C.B.C Granulopenia in acute brucellosis
Lymphocytosis in chronic brucellosis Atypical lymphocytosis Anemia
due to hypersplenism Thrombocytopenia causing hemorrhage Moderate
elevation of ESR
Slide 38
38 Laboratory changes Bacteriologic tests Taking bone marrow is
more rewarding Brucella can be isolated from liver taken by biopsy
Human semen may be positive
Slide 39
39
Slide 40
40 Serologic Tests IgM in acute brucellosis Rises first Is the
only antibody for the first weeks Peaks at about 3 months Drop off
after 3 months
Slide 41
Untreated Brucellosis 41
Slide 42
Treated Brucellosis Treatment 42
Slide 43
43 Laboratory changes Serologic Tests Serologic tests are based
on rising and falling of IgM and IgG During re-infection or
exacerbation, antibody titers become elevated In relapses, IgG may
be the only antibody which rises
Slide 44
44 Standard tube agglutination test Is the most frequently
utilized test Measuring antibodies to brucella abortus antigen A
fourfold or greater rise in titer to 1:160 or higher is
significant
Slide 45
45 Standard tube agglutination test Titer of => 1:160 is
suggestive if there is symptoms consistent with brucellosis Acute
brucellosis is most likely to be associated with a titer above
1:160 A great majority of patients will have titers of 1:160 to
1:320
Slide 46
46 Standard tube agglutination test Individuals with
subclinical infection may demonstrate significant STA titers A
diagnosis of brucellosis can not be established on the titers alone
STA test can not differentiate persisting active infection from
treated brucellosis
Slide 47
47 Standard tube agglutination test In chronic localized
brucellosis STA titers may appear absent or low It is not useful in
differentiating relapsing infection from other febrile illnesses in
patients with past brucella infections
Slide 48
48 Standard tube agglutination test False positive results : F.
tularensis Y. enterocolitica V. cholera Salmonella Vaccine against
F. Y. V & S. Brucella skin testing Stenotrophomonas maltophila
E. coli O157
Slide 49
49 Standard tube agglutination test False negative results
Agammaglobulinemia First week of disease Disease due to Br. Canis
Chronic brucellosis Prozone phenomenon
Slide 50
False-negative results in STA test Prozone & postzone
phenomenon ( ) ( ) 50
Slide 51
51 False-negative results in STA test Prozone phenomenon The
Prozone phenomenon appears to be related to the presence of IgG or
IgA (Blocking antibodies) It can be eliminated if dilutions are
carried out to at least 1:1280
Slide 52
52 False-negative results in STA test Brucella Canis infection
The antigen used in the STA test does not reacts with brucella
Canis If Br. Canis infection is suspected serologic tests specific
for Br. Canis must be requested
Slide 53
53 False-negative results in STA test Chronic brucellosis STA
test may be positive in low titer or may be negative Coombs test
and C.F. tests may be positive A positive coombs test and CF test
at 1:16 in such cases is strung evidence of continuing
infection
Slide 54
54 Serologic Tests 2-Mercaptoethanol test (2ME) The STA test
measures both IgM and IgG The addition of 2ME to the STA test
results in the destruction of disulfide bonds of IgM 2ME test
result is the detection of only IgG
Slide 55
55 Serologic Tests 2-Mercaptoethanol test (2ME) With prompt and
adequate therapy IgG usually become undetectable within 5-12 months
Those patients who develop persistent infection usually maintain
elevated IgG agglutinins
Slide 56
56 Serologic Tests 2-Mercaptoethanol test (2ME) 2ME test will
be negative if STA test is really negative 2ME test is less
sensitive than STA test The prognosis of acute brucellosis may be
predicted from the fall of 2ME
Slide 57
57 Serologic Tests 1:160 1:160
Slide 58
58 Serologic Tests A and M antigens Antigen A and M are common
to the three main brucella species In the Br. Abortus, there is
more A antigen than M antigen In the Br. Melitensis there is more M
antigen than A antigen A M M A BABM
Slide 59
59 Serologic Tests A and M antigens Specific antigen may show
higher agglutinin titers in patients infected with brucella other
than Br. Abortus Ideally in all countries prepared antigen for
serological testing should consist of predominant species A M M A
BA BM
Slide 60
60 Serologic Tests A and M antigens In IRAN We have human
brucellosis nearly always due to Br. Melitensis but use Br. Abortus
antigen Br. Abortus antigen in our laboratories shows lower
agglutinin titers A M M ABA BM
Slide 61
61 Serologic Tests A and M antigens In IRAN We must accept
titers lower than 1:160 if there is signs and symptoms compatible
with brucellosis A M M ABA BM
Slide 62
Comparison of serological tests using Br. Abortus and Br.
Melitensis antigen Tests Due to Br. AbortusDue to Br. Melitensis A
antigenM antigenA antigenM antigen STA Coombs 1:640 1:1280 1:320
1:640 1:5120 1:1280 1:10240 62 Ideally in all countries prepared
antigen for serological testing should consist of predominant
species
Slide 63
63 Serologic Tests Coombs test Serologic Tests Coombs test
Serum may contain brucella antibodies which do not produce
agglutination Non agglutinating antibodies are called incomplete
antibodies Incomplete antibodies can be detected by addition of
rabbit anti- human globulin
Slide 64
64 Serologic Tests Coombs test If STA is negative and there are
symptoms and signs compatible with chronic brucellosis, then coombs
titer of => 1:40 should be considered positive Coombs test is
not recommended when STA test is positive
Slide 65
65 Serologic Tests Complement fixation test The CF test
measures IgG antibodies Titers of => 1:16 should be considered
positive
Slide 66
66 Serologic Tests Radioimmunoassay test RIA test determines
anti-brucella IgM and IgG Avoids the difficulties with blocking or
non-agglutinating antibodies Can differentiate between chronic and
acute brucellosis
Slide 67
67 Serologic Tests ELISA test ELISA test can distinguish acute
cases from chronic cases In ELISA test cross reaction can occur
with yersiniosis
Slide 68
68 Serologic Tests Rose Bengal plate test Is an agglutination
test in which the brucella cells are bound to a dye Is quick and
easy to read It is a useful screening test
Slide 69
69 Brucella skin test (Brucellin) Demonstrate delayed
hypersensitivity The antigen is a filtrate of a culture of brucella
organisms or purified extract Injects intradermally
Slide 70
70 Brucella skin test (Brucellin) The test is positive if local
redness with induration is present after 24-48 hours Antigen can
provoke an antibody response or a significant rise in a
pre-existing response Brucellin test, should not be performed
Slide 71
71 Laboratory changes PCR Tests The sensitivity was 100% The
specificity of the test was 98.3%
Slide 72
Prognosis Preantibiotic era Mortality 2% mainly endocarditis
Morbidity High with B. melitensis Nerve deafness Spinal cord damage
72
Slide 73
Prognosis May last days, months, or years Recovery is common
Disability is often pronounced About 5% of treated cases relapse
Failure to complete the treatment regimen Sequestered infection
requiring surgical drainage Case-fatality rate: