Brucellosis (
Undulant fever—Malta
fever—Mediterranean fever
)
Identification-
Identification-
a systemic bacterial disease of
acute
or
insidious onset; with fever, headache, weakness,
profuse sweating, chills, arthralgia, depression,
weight loss, and generalized aching.
localized suppurative
infections of organs
chronic
localized infections
subclinical
disease
The disease may last days, months, or occasionally a
year or more if not adequately treated.
Identification-
Osteoarticular
complications occur in 20%-
60%.
Genitourinary
involvement seen in 2%-20%.
Neurobrucellosis
occurs in 3%-7%.
The case fatality rate
of untreated brucellosis
is
2%.
Part or all of original syndrome may reappear
as
relapses
.
A neurotic symptom complex
is sometimes
misdiagnosed as chronic brucellosis.
Identification-
laboratory diagnosis
Isolation of infectious agent
from blood,
bone marrow, or other tissues, or
discharges.
Serological tests
(Rose Bengal and sero
agglutination) with other tests (Coombs
–IgG or ELISA-IgG) .These methods do not
apply to
B.canis
.
Epidemiology
Infectious agent.
Brucella
abortus
,
biovars 1-6 and 9;
B.melitensis
biovars
1-3;
B.suis
biovars 1-5; and
B.canis
.
Epidemiology
Occurrence.
Worldwide
, especially Mediterranean
countries (Europe and Africa), the Middle East,
Africa, central Asia, central and South
America, India, and Mexico.
Sources of infection
and responsible organism
vary
according to geographical area.
Cases are increasingly documented in non-
endemic areas due to
international travel
Epidemiology
Brucellosis is
an occupational disease
Another major risk factor for cases and
outbreaks
is consumption of raw or
unpasteurized milk and milk products
Epidemiology
Isolated cases of infection with
B
.
canis
occur
in
animal handlers
.
The disease is often
unrecognized and unreported.
Rare
cases of
marine-associated brucella
species reported.
Brucellosis remains among the most common
laboratory acquired
bacterial infections.
Epidemiology
Reservoir
Cattle, swine, goats and sheep
.
Dog
Coyotes
Marine mammals
Epidemiology
M ode of transmission
Contact
through breaks in the skin
Ingestion
of raw milk and dairy products
(unpasteurized cheese) from infected animals.
Airborne
infection
.
Accidental
self-inoculation with vaccine
.
Epidemiology
Incubation period:
Commonly
1-2 months
Epidemiology
Period of communicability
Rare person to person transmission
.
Epidemiology
Susceptibility
–
severity and duration of clinical illness
vary
.
Duration of acquired immunity
uncertain
Preventive measures
Preventive measures
Health education of the public
Health education of farmers and workers in
slaughterhouses, meat processing plants and butcher
shops
Health education of hunters
Preventive measures
Search for infection among livestock by serological
testing and by ELISA or testing of cows "milk (ring
test);
eliminate infected animals (segregation and
/or slaughtering).Infection among swine usually
requires slaughter of the herd. in high prevalence
area immunize young goats and sheep with live
attenuated Rev-1strain of B.melitensis ,and
immunize calves and sometimes adult animals with
strain 19 ,B.abortus .Since 1996 ,strain RB51 of
B.abortus has largely replaced strain 19 for
immunization of cattle .RB51 was designed to be
less virulent for human when accidentally injected .
Preventive measures
Rev-1 is resistant to streptomycin, and RB51 is
resistant to Rifampicin.
This must be taken in
consideration when treating human cases of animal
vaccine infection.
Pasteurize milk and dairy products
from cows,
sheep and goats. Boiling milk is effective when
pasteurization is impossible. Do not eat meat from
animals that appear ill.
Exercise
care in handling and disposable of
placenta, discharges and fetuses
.
Disinfect
contaminated areas.
Control measures
Control of patients, contacts and
immediate environment
Report to local health authority –obligatory in
most countries.
Class 2
.
Isolation:
Draining and secretion precautions
if there are draining lesions; otherwise none.
Concurrent disinfection
:
Of purulent
discharges
.
immunization of contacts :
Not applicable
Control measures
Specific treatment:
combination
of
doxycycline
(200mg daily) and
Rifampicin
(600-900mg daily) or streptomycin (1gm
daily) for
at least 6 weeks
. Relapses occur
in 5%-15% of cases due to sequestered
rather than resistant organisms.
Monotherapy should be avoided as relapses
can be as high as 50%. Arthritis may occur
in recurrent cases.
Control measures
Epidemic measures
Search for
common vehicle
of infection
,usually raw milk or milk products –especially
cheese –from an infected herd .Recall
incriminated products ;stop production and
distribution unless pasteurization is instituted
Disaster implications: None
Control measures
International measures:
Control of domestic animals and animal
products in
international trade
and
transport
.WHO collaborating centers
provide support as required
Control measures
Measures in the case of deliberate
use:
The potential to infect humans and
animals through
aerosol
exposure,
combined with
a low infectious dose
of
10-100 organisms, is such that Brucella
species may be as a potent biological
weapon.