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8/13/2019 Brucellosis- a neglected zoonosis
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Brucellosis- A neglected zoonosis
By
Ajay Pathak
8/13/2019 Brucellosis- a neglected zoonosis
2/20
What is brucellosis ?
Brucellosis- important re-emerging zoonosis with a worldwide
distribution
It is primarily a disease of reproductive system of sexually
matured animals with concomitant loss in productivity of
affected animals
Causative agentBrucellaspp.
Brucella spp.- Gram negative, aerobic, non spore forming, non-
encapsulated, coccobacilli
Facultative intracellular pathogen
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The Many Names of Brucellosis
Human Disease
Malta Fever
Undulant Fever
Mediterranean Fever
Rock Fever of Gibraltar
Gastric Fever
Animal Disease
Bangs Disease
Enzootic AbortionEpizootic Abortion
Slinking of Calves
Ram Epididymitis
Contagious Abortion
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Taxonomic History of Brucella
1887: David Bruce Micrococcus melitensis
1897: B. Bang Bacillus abortus
1920: K.F. Meyer et. al. Brucella gen. nov.
1929: I.F. Huddleston B. suis
1956: M.B. Buddle B. ovis
1957: H.B. Stoenner B. neotomae
1968: Carmichael
& Bruner B. canis
2007: Foster et. al. B. ceti & B. pinnipedialis
2008: Scholz et. al. B. microti
2008-10: De et. al.&
Scholz et. al. B. inopinata
2010: Tiller et. al. Two new Brucella spp.
Strain BO2 from a human patient
(Australia)
7 rodent Brucellastrains from Australia
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Genus Brucella
Class -Alphaproteobacteria
Order -Rhizobiales
Family -Brucellaceae
Genus Brucella- 10 species affecting distinct primary hosts
B. abortus preferentially infects cattle, B.melitensis sheep andgoats, B. suis pigs, B.ovis sheep and B. canis dogs.
Above species infect humans with B.melitensis and B. abortus
being the most common.
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Species Biovars Preferential
host(s)
Pathogenicity in
humans
B. melitensis 1-3 sheep, goat highB. abortus 1-6, 9 Cattle high
B. suis 1, 3 Pig high2 wild boar, hare low
4 reindeer, caribou high
5 Rodent no
B. neotomae - desert rat moderateB. ovis - Ram No
B. canis - Dog moderateB. pinnipedialis - Seals ?
B. ceti - Cetaceans ?B. microti - soil, vole, fox ?
B. inopinata - Human ?
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Symptoms In humans
undulant fever, weight loss, muscular pain,
arthritis, excessive sweating,
malaise, anorexia, headache,
back pain, orchitis
Complications- osteoarthritis,endocarditis and several neurological
disorders
In animals
abortion in third trimester of pregnancy, stillbirth, orchitis in
males, retained placenta, endometritis, hygroma, occurance of
Brucellaorganisms in secretions(milk, vaginal fluid and other
body fluids)
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General characteristics The genomes of Brucella abortus, B. melitensis and some
biotypes of B. suis contain two distinct chromosomes
Brucellaspp. lacks most of the traditional virulence factors like
capsules, secreted proteases, exotoxins, endotoxins, pili and/or
fimbriae or virulence plasmids, seen in other pathogens
The lipopolysaccharide (LPS) layer of pathogenic Brucella is less
immunogenic than that of most Gram-negative organisms
because it does not bear a marked PAMP
Many strains require supplementary CO2 for growth
Usually oxidase and urease positive
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Global scenario
The zoonotic pathogens B. abortus, B. melitensis, and B. suis
were designated asSelect Agents of Category B by CDC, USA.
Brucellosis is widely distributed all over the world and it is one
of the world's major zoonotic problems accounting for the
annual occurrence of more than 500,000 cases (Pappas et al.
2006).
Worldwide, reported incidence of human brucellosis in
endemic disease are as varies widely, from 200 per
100,000 population
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Worldwide Incidence of Human Brucellosis
Pappas et al. The new global map of human brucellosis: Lancet Infect Dis, 2006;6(2):91-9.
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Bovine brucellosis (B. abortus) has been eradicated from
Australia, Canada, Cyprus, Denmark, Finland, The Netherlands,
New Zealand, Norway, Sweden and the United Kingdom
It remains an uncontrolled problem in regions of high
endemicity such as the Africa, Mediterranean, Middle East,parts of Asia and Latin America
The recent isolation of distinctive strains from marinemammals and humans has extended the ecologic range of the
genus and, potentially its scope as a zoonosis
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Indian scenario
Serological evidences are suggestive of high endemicity of
brucellosis in India.
It was first reported in 1942. B. abortus biotype-1 is the
predominant infective biotypes in cattle and buffaloes while B.melitensis biotype-1 is in sheep, goats and man.
In India, 5% cattle, 3% buffaloes, 7.9% sheep and 2.2% of goats
are infected with brucellosis (Renukaradhya et al. 2002).
Growing dairy industry in India- Increased risk due to increased
trade and rapid movement of livestock
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In a detailed study of 47 organized farms in the southern State of
Karnataka by Isloor et al. (1998), 207 of 4,995 (4.1%) serum samples from
cattle showed titres for brucellosis. In organized farms with a history ofabortion, placenta retention and repeat breeding, the prevalence rate was
17%.
Chahota et al. (2003) reported an outbreak of brucellosis in an organized
dairy farm, leading to abortions, retained placenta and stillbirths in cows atHimachal pradesh. In a dairy herd of about 290 animals 24 pregnant cows
in the farm at the time of outbreak were affected. The Brucella abortus
biotype-I was isolated from infected animals.
India has an enormous cattle wealth. The disease has been repeatedly
reported in the animals in India. However, very few human studies have
been undertaken. It is estimated that the true incidence is 25 times higher
than the reported cases due to underdiagnosis
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Author Reports
Mathur (1964) Reported seroprevalence of 8.5% among dairy workers and
4.2% in aborted women. He also isolated Brucellaspp. from
the blood of 7 human cases from north India
Panjarathinam (1984) Reported seroprevalence of 6.46% in aborted women
Rana et al. (1985) Reported brucellosis (20.7%)among workers of veterinary
hospitals and slaughter house of Union Territory of Delhi
Kumar et al.(1997) Reported seroprevalance of 20.6, 12.75, 25.45% by RBPT,
STAT,ELISA among abattoir personnel of Delhi
Handa et al.(1998) Reported 11.11% seroprevalence in north India
Kadri et al.(2000) Reported seroprevalnce in 0.8% patients of pyrexia of
unknown origion (PUO) in Kashmir
Kalla et al.(2001) Reported outbreak of polyarthritis with pyrexia related to
brucellosis in Western Rajasthan (48 cases)
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Author Reports
Thakur and Thapliyal (2002) Reported a seroprevalence of 17.39% in field
veterinarians and abattoir workers
Sen et al.(2002) Seropositive cases were seen in 28 of 414 (7.0%)
patients of PUO in Varanasi
Mudaliar et al. (2003) Reported 5.33 % seropositivity in animal handlers of
Maharashtra
Mantur et al.(2007) Reported seroprevalence of 1.6% by STAT and isolated B.
melitensisin 43 pediatric patients during a period of 13years. During the same period they diagno sed 492
adult patients from Belgaum, Karnataka
Jain et al.(2008) Reported 31.28% seropositivity and obtained 8 isolates
of Brucellamelitensis biotype 1 from Varanasi
Sathyanarayanan et al. (2011) Reported 61 out of 68 seropositive cases by STAT from a
tertiary care center in karnataka
Appannanavar et al. (2012) Reported 9.98% seropositivity by STAT from tertiary care
centre in north India
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Samples
Blood (with and without anticoagulant)
Milk
Vaginal Swabs
Vaginal Discharge
Placental tissue
Aborted fetus- stomach content, spleen, lung, liver, heart blood, peritoneal
fluid
Human serum in plain tube
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Processing of samplesSerological tests-
Rose Bengal Plate test (RBPT)-
38 animal samples were found
positive by RBPT
Standard tube agglutination Test (STAT)
Indirect ELISA
IgG IGM ELISA
Negative Positive
RBPT
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Isolation of Brucella
Isolation was performed according to standard
procedures described by Alton et al. (1975)
Milk
Centrifuged at 8000 rpmPellet & cream Inoculated on Brucellaagar
Incubated for 3-4 days at 370C
Vaginal swabsenrichment in supplemented Brucellabroth for 48 hrs
Streaked on Brucellaagar with selective supplement
Incubated for 3-4 days at 370C
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Identification
Gram staining- Small, gram negative cocobacilli in clumps
Oxidase Test- positive
Catalase test- positive
Rapid Urease testpositive
Nitrate reduction- positive
Dye inhibition test using thionin and basic fuchsin
PCR detection of the bcsp31 andIS711 genes
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Thank you