Brucellosis ppt

BRUCELLOSIS
Anjana K.C.
Roll no. 27
MSc. 3rd Semester
Central Department of Microbiology

Introduction
• Brucellosis is one of the zoonotic infection caused by the bacterial
genus Brucella, continues to be major public health problem
world wide.
• Zoonotic nature of the Brucellosis was demonstrated in 1905 by
Zammit isolating Brucella melitensis from goat’s milk in Malta.
• One of the infectious diseases transmissible from animals to
humans by ingestion of infected food products, direct contact with
an infected animals (sheep, cattle, goat, pigs or other animals), or
inhalation of aerosis.

• Many names of the brucellosis;
HUMAN DISEASES ANIMAL DISEASES
Malta fever Bang’s diseases
Undulant fever Enzootic abortion
Mediterranean fever Epizootic abortion
Rock fever of Gibraltar Slinking of calves
Gastric fever Contagious abortion

Bacteriology
• Morphology
 Small (0.5-0.7 × 0.6-1.5μm), gram negative, non-motile, non-capsulate,
non-sporing coccobacilli
 Arranged singly, sometimes in pairs and small clusters
• Culture
 Strict aerobes
 Fastidious and nutritional requirement are complex
 Grow best in on tryptose soy based or other enriched media
 Optimum temperature is 37°C and pH 6.6 to 7.4
 Addition of 5-10% CO2 improves the growth of B. abortus and B.
melitensis
 Addition of bacitracin, polymyxin or cycloheximide makes media
selective for brucellae

• Biochemical reactions
 Catalase positive, oxidase positive (expect for B. ovis and B.
neotomae) and urease positive
 Indole negative, MR-VP negative, citrate negative,
 Do not grow on MA.
 Reduce nitrate to nitrites
• Localize in the reproductive organs of the host animals, causing
abortions and sterility.
• Shed in large no. in the animals urine, milk, placental fluid and
others fluids.

Geographical distribution
• The diseases brucellosis occur worldwide, especially in countries
of Mediterranean, parts of Mexico, south and the center of
America, Africa, Asia, Arab peninsula, Indian subcontinent and
the Middle East.
• Source of infection and responsible organism vary according to
geographic area.
• Brucellosis is predominantly an occupational diseases of those
working with infected animals especially farm workers,
veterinarians and abattoir workers. Hence more frequent among
males.
• Sporadic cases and outbreaks occur among consumers of raw
milk and milk products (especially unpasteurized soft cheese)
from cow, sheep and goat.

Agent and Reservoir
• Various types of the Brucella species of bacteria exist (B. abortus, B.
melitensis, B. ovis, B. canis). B. melitensis is the most virulent and causes the
most severe and acute cases of brucellosis. B. abortus is associated with mild
to moderate sporadic disease that rarely causes complications.
Species Animal Reservoir
B. melitensis goats and sheep Majority of human cases (3 biotypes)
B. abortus cattle 7 biotypes
B. canis dogs
B. suis Pigs (swine) 5 biotypes
B. ovis Sheep (Not known to cause human diseases)
B. neotomae Rodents (Not known to cause human diseases)
B. pinnipedialis seal marine mammals – reservoir, but sporadic human
pathogens
B. ceti dolphin, porpoise, whale
B. microti common vole
B. inopinata unknown

Mode of transmission
Transmitted to humans by following ways:
a. Ingestion: Primarily by consuming raw milk or milk products (such as
unpasteurized soft cheese), meat of infected animals. Also be transmitted by
drinking water or eating raw vegetables contaminated with faces or urine of
infected animals.
b. Direct contact: Infection is acquired by direct contact with infected animals.
Inoculation through cuts and skin abrasions from handling infected animals
carcasses, placentas or contact with animal vaginal secretion or urine.
c. Inhalation: Infection is the transmitted by inhalation of dust from wool or
other dried material of infected animals. Infection by inhalation is important
among veterinarians and laboratory workers
d. Accidental inoculation: Accidental needle stick puncture with Brucella B19
vaccine while vaccinating animals. Also a serious risk in laboratory workers
who handle culture of the organism.

Pathogenesis
Brucella organisms
Entry via lesions or cuts, ingestion or inhalation
Phagocytosed by macrophages
Survive and replicates with phagocytes and monocytes (much of the pathogenesis
of brucellosis is associated with intracellular survival)
Infected macrophages localize in reticuloendothelial system namely lymph nodes,
liver, spleen and bone marrow
Results to formation of granuloma with lymphocytes and epitheloid gaints cells,
which can progress to form focal abscesses and caseation
a. Virulent brucellae

b. Avirulent strain
Ingested by mononuclear or polymorphonuclear leucocytes
No symptoms of disease
• Placentas and fetal membranes of cattle's, sheep contains erythritol, a
growth factor for brucellae. The proliferation organism in pregnancy
animals leads to placentitis and abortion.
• No erythritol in human placentas thus abortion is not part of Brucella
infection of humans

Brucellosis: Phase of diseases
• Incubation phase: before clinical symptoms are evident.
• Acute phase: during which time the pathogen invades and disseminates in
host tissue
• Chronic phase:
 ability of the organism to persist in the cells of the host in which brucellae
are distributed by way of the lymphoreticular system
 to eventually cause cardiovascular, hepatic, lymphoreticular, neurologic, and
osteoarticular disease
 can eventually result in severe organ damage and death of the host organism

Clinical manifestation
• Incubation period - 1-3 weeks (up to several months)
• Target population - All age groups (occupational exposure)
• Acute brucellosis (influenza like syndrome) :
 Undulant fever (usually peaks in the evening and slowly returns to
normal by morning)
 Headache
 Limb and back pains are unusually severe, night sweating and fatigue
are marked
 Anorexia, weakness, loss of weight, depression
• Chronic brucellosis:
 It is usually non-bacteremic.
 There is lassitude sweating and joint pain.
 Symptoms last for 3-6 months and occasionally for a year or more.

• Complications:
 Arthritis, meningitis, spondylitis, uveitis, orchitis
 Endocarditis (caused by B. melitensis infection) is rare (< 2%) but has
a high fatality rate (approx. 80%)
• Human brucellosis can cause chronic debilitating illness.
Complications may affect any of the organ systems.
• B. Melitensis infections are characterized by more severe clinical
symptoms than other brucellosis.
• The fever may occur in cycle with febrile periods alternating with
afebrile periods. This fever pattern had given the diseases the name of
undulant fever.
• With the development of cell mediated immunity body is better able to
contain and eliminate Brucella organism.

Diagnosis
https://medchrome.com/basic-science/microbiology/brucella-and-brucellosis/
Specimen:
Blood, Urine, sputum, Milk, Lymph node biopsy, Bone-marrow aspirate,
Vaginal secretions (swabs), Semen

Diagnosis:
 Clinical features
 Serology
 Blood or tissue culture
 PCR
Serodiagnosis
Diagnosis are based on antibody detection. These includes:-
• Serum agglutination test (standard tube agglutination test)
 Most commonly used serological test
 Detects the presence of antibodies against LPS components of Brucella
 Useful for the diagnosis of brucellosis caused by B. abortus, B.
melintensis and B. suis but not useful for B. canis.
 Considered positive when titers are greater than or equal to 1 in 160 or
when fourfold rise is demonstrated in convalescent sera.
• 2ME (Mercaptoethanol) test: more specific, positive in chronic
brucellosis

• ELISA
 Most sensitive test for the detection of IgM, IgG and IgA Brucella antibodies
during acute and chronic brucellosis.
 High IgM in acute infection
 High IgG in chronic infection
• Others tests- coombs, FTA, CFT
False positive: cross reactivity with ab. of E.coli, V. cholerae
False negative: in Prozone phenomenon.
Culture of Blood, Bone marrow and Tissue fluids
 Blood culture: positive in about; 50-70% of cases
 Bone marrow culture: standard criterion since reticuloendothelial system holds a
high concentration of organism. Sensitivity- 80 to 90%
Blood or bone cultures should be incubated atleast 6 weeks.
PCR (Polymerase Chain Reaction)
 Rapid and accurate method for the diagnosis of Brucella species

Diagnosis in animals
• Rapid latex agglutination and Rose Bengal test: Rapid
diagnosis methods and also used for the diagnosis of brucellosis
in cattle production
• Milk ring test: Frequently used serological test in which
Brucella agglutinins are detected in the milk of infected dairy
cattle. A positive test shows a blue line above the white skim-
milk..

Treatment
• Successful vaccines have been developed for livestock while there
is no vaccine available for humans, but an extended course of
antibiotics is recommended.
• Combination of tetracycline and doxycycline is effective.
• Combination of doxycycline with rifampin is effective.
• Doxycycline (dosage-200mg/day) in addition with streptomycin
(dosage-1g/day) given intramuscularly for 2-3 weeks is most
effective for treatment of brucellosis in adults

Prevention and Control
• Humans
 People should reduce exposure to infected animals or byproducts. Consume only
properly cooked meat and pasteurized or boiled milk and dairy products from cows,
sheep, and goats.
 Hygiene is the best preventative measure for workers who are in contact with
animals on a daily basis; this applies to farm, meat production chain and laboratory
personnel.
 Provide instructions in infection-control practices to minimize risk of exposure.
 If infection is detected in an individual, an antibiotic treatment is usually prescribed
for a specific duration of time. Sometimes a surgical intervention is needed, but full
recovery is common.
• Animals
 The key to prevent brucellosis in an animal herd is to be rigorous. Always isolate
newly purchased animals to make sure they are brucellosis free.
 Laboratory techniques used to identify the cause of abortion is also a way to single
out sick animals.
 Good disposal of placentas and non-viable fetuses is important to reduce the risk of
contamination.
 Hygiene and precautionary measures are the best allies for prevention.

• The most effective way to control this disease is by vaccination. A
strain of B. abortus is injected most commonly in sexually
immature females to minimize the risk of abortion caused by the
vaccine which can be an effective method for elimination of
clinical diseases and to reduce the number of organisms excreted
per animal.
• Eradication of B. abortus is hard to achieve because it requires a
surveillance system, laboratory support and a high level of
hygiene.

https://doi.org/10.4178/epih.e2016042
Review of brucellosis in Nepal
Brucellosis is a significant public health problem in Nepal. The first human
case was reported in 1979 when the disease was diagnosed by the isolation
of B. melitensis in a shepherd from Pokhara, who most likely acquired the
disease from his sheep.

The presence of brucellosis in Nepal was first reported in 1977
https://doi.org/10.4178/epih.e2016042

Bibliography
• Parija SC (2016). Brucella: Textbook of Microbiology and Immunology, third edition,
India:El;sevier, 325-331
• Hasanjani Roushan MR and Brahimpour S (2015). Human brucellosis: An
overview. Caspian journal of internal medicine, 6(1), 46–47.
• Christopher S, Umapathy BL, Ravikumar KL (2010). Brucellosis: review on the recent
trends in pathogenicity and laboratory diagnosis. Journal of laboratory physicians, 2(2),
55–60
• Ebrahimpour S, Youssefi MA, Karimi N, et al. The prevalence of human brucellosis in
Mazandaran province, Iran. Afr J Microbiol Res. 2012;6:4090–4.
• Pappas G, Papadimitriou P, Akritidis N, Christou L, Tsianos EV. The new global map of
human brucellosis. Lancet Infect Dis. 2006 Feb; 6(2):91-9.
• Acharya KP, Niroula N, and Kaphle K (2016). Review of Brucellosis in
Nepal. Epidemiology and health, 38, e2016042. https://doi.org/10.4178/epih.e2016042
(Retraction published Epidemiol Health. 2017 Apr 24;39:e2017018)

Brucellosis ppt

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