Brucellosis- a neglected zoonosis

8/13/2019 Brucellosis- a neglected zoonosis

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Brucellosis- A neglected zoonosis

By

Ajay Pathak


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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 testpositive

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

Brucellosis- a neglected zoonosis

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