Brucellosis and Hepatitis B Quiz

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Questions and Answers

What is Brucella primarily classified as?

A Gram-positive bacillus

A virus

A spirochete

A Gram-negative coccobacillus (correct)

Which species of Brucella is associated with cattle?

Brucella ovis

Brucella abortus (correct)

Brucella melitensis

Brucella suis

What is the incubation period typically required for the cultivation of Brucella?

8-9 weeks

1-2 weeks

3-4 weeks

6-7 weeks (correct)

Which of the following is NOT a mode of transmission for Brucellosis?

Ingestion of contaminated meat (B) Signup and view all the answers

Which clinical manifestation is NOT commonly associated with Brucellosis?

Jaundice (C) Signup and view all the answers

What is the purpose of pasteurization in the prevention of Brucellosis?

To kill potential pathogens including Brucella (B) Signup and view all the answers

What type of virus is Hepatitis B Virus (HBV)?

DNA virus (B) Signup and view all the answers

Which component is NOT found in the outer shell of Hepatitis B Virus?

HBcAg (A) Signup and view all the answers

What is the role of excess HBsAg released from the Hepatitis B Virus?

To stimulate production of neutralizing antibodies (A) Signup and view all the answers

Which clinical finding is associated with Hepatitis B Virus infection?

Enlarged spleen (D) Signup and view all the answers

What is the incubation period for HBV infection?

6 weeks to 6 months (A) Signup and view all the answers

What does the presence of HBsAg indicate?

Acute infection (D) Signup and view all the answers

Which transmission mode has the highest rate for HBV?

Perinatal transmission (B) Signup and view all the answers

Which of the following is a common extra-hepatic manifestation of HBV?

Rash (B) Signup and view all the answers

What is the hepatitis B vaccine composed of?

Recombinant HBsAg (C) Signup and view all the answers

What does Anti-HBs (+) indicate?

Immunity from vaccination (B) Signup and view all the answers

Which of these is an effective method for preventing HBV transmission?

Blood screening before transfusion (A) Signup and view all the answers

What is a common symptom of acute HBV infection?

Nausea (C) Signup and view all the answers

What is the primary site of HBV replication in the body?

Liver (A) Signup and view all the answers

What can characterize fulminant hepatitis caused by HBV?

Is associated with acute liver failure (C) Signup and view all the answers

Study Notes

Blood Stream Infections 2

Presented by Dr. Heba Ahmed, lecturer of Medical Microbiology & Immunology

Brucella and Brucellosis

Overview of characteristics, pathogenesis, diagnosis, and prevention of Brucella and Brucellosis are covered

Characteristic Features

Brucella are short Gram-negative coccobacilli
They are aerobic and facultative intracellular pathogens
Primarily pathogens of animals

Species of Brucella Infecting Humans

Brucella abortus: Infects cattle, causes abortion
Brucella melitensis: Infects sheep and goats
Brucella suis: Infects pigs

Culture Characteristics

Grow on enriched media
B. abortus requires 10% CO₂ for growth
Culture characteristics aid in diagnosis

Biochemical Reactions

Biochemical tests differentiate Brucella genus and species
These tests aid in definitive identification.
A table listing CO₂, H₂S, and Urea test results for different Brucella species is provided

Brucellosis

Also known as Undulant Fever or Malta Fever
It is a zoonotic disease.
Countries with reported cases of brucellosis and human transmission are highlighted on a map

Modes of Transmission

Ingestion of contaminated unpasteurized milk or milk products
Direct contact with infected animals via skin abrasions
Inhalation of aerosols from infected animals or cultures

Pathogenesis

Brucella enter regional lymph nodes and proliferate
Acute lymphadenitis (lymph node is enlarged and hyperplastic)
Reach the bloodstream through the thoracic duct, causing bacteremia
Localized to different organs
Phagocytized by cells, resist intracellular killing, evade immune controls, grow in phagocytes
Spreads to spleen, liver, lymph nodes, bone marrow
Granulomas develop around infection foci

Clinical Manifestations

Symptoms including fever (undulant), chills, weakness, sweating, headache, body aches
Findings such as enlarged lymph nodes, liver, and spleen enlargement
Potential complications including osteomyelitis, endocarditis, meningitis

Laboratory Diagnosis A, Specimens

Specimens: Blood or bone marrow (during acute illness phase)
Cultivation: Rare due to long incubation periods (6-7 weeks), and risk
Serologic Diagnosis (STAT): Identifies IgM and IgG antibodies
ELISA: Measures IgG or IgM antibodies
Brucellin Test: A skin test for delayed hypersensitivity

Prevention Strategies

Pasteurization of milk and products
Vaccination with live attenuated vaccines (e.g., for cattle)
Control of animal infections

Hepatitis B Virus (HBV)

HBV is a DNA virus that causes serum hepatitis.

Hepatitis B Virus (HBV) Structure

Intact virion: Known as the Dane particle (42 nm diameter).
Structure: Composed of outer shell (HBsAg) and core containing HBcAg, HBeAg, DNA-dependent DNA polymerase, and partially double-stranded DNA
Outer Shell (Lipoprotein): HBsAg; excess released as non-infectious particles (spherical: 22-25 nm; tubular: 200 nm).
Function: Stimulates neutralizing antibodies for long-term protection
Core: Contain HBcAg, HBeAg, and viral DNA polymerase
Genome: Partially double-stranded DNA

Hepatitis B Virus (HBV) Modes of Transmission

Body fluids: High viral load (~10⁹ copies/mL of serum).
Main Routes: Perinatal transmission, blood and percutaneous transmission, sexual transmission
Comparison: Higher transmission rate (30%) than HIV (0.3%) and HCV (3%).

Pathogenesis and Clinical Presentations

Pathogenesis: HBV replicates in the liver, causing hepatic dysfunction
Extrahepatic Manifestations: Immune complex-related (rash, urticaria, polyarthralgia, vasculitis, glomerulonephritis)
Incubation Period: 6 weeks to 6 months
Onset: Gradual
Symptoms: Malaise, anorexia, nausea, vomiting, abdominal pain, jaundice, rashes, joint pain, arthritis, enlarged, tender liver

Prognosis and Outcomes

Fulminant Hepatitis: Occurs in 1-2%, hepatic failure in 0.1-0.5%
Chronic Infection: Chronic active hepatitis, cirrhosis & liver failure, hepatocellular carcinoma
Recovery: Most patients recover fully within 4-6 months

Laboratory Diagnosis

Serology: HBsAg (early marker, indicates infection), Anti-HBs (immunity marker), Anti-HBc (IgM-recent infection; IgG-past infection), HBeAg (high infectivity), Anti-HBe (recovery marker).
Molecular Tests: DNA polymerase activity, HBV DNA via PCR
Liver Tests: ALT, bilirubin

Interpretation of HBV Serology

HBsAg (+), Anti-HBc (+), Anti-HBs (-): Acute infection
HBsAg (-), Anti-HBc (+), Anti-HBs (-): Window phase
HBsAg (+), Anti-HBc IgG (+), Anti-HBs (-): Chronic infection
Anti-HBc IgG (+), Anti-HBs (+): Immunity from natural infection
Anti-HBs (+): Immunity from vaccination

Virus Replication

Replication Site: Liver
Partial DNA converted to full double-stranded DNA, mRNA formation, viral protein synthesis, and genome replication
Significance: Replication level affects clinical manifestations

Prevention and Control

General Measures: Blood screening before transfusion, Standard precautions (hand hygiene, gloves, disposable syringes)
Specific Prophylaxis: HBV vaccine (recombinant HBsAg vaccine, three doses 0, 1, 6 months). Hepatitis B Immunoglobulin (HBIG), post-exposure prophylaxis

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Description

Test your knowledge on Brucella and Hepatitis B Virus with this comprehensive quiz. Explore topics including transmission modes, incubation periods, clinical manifestations, and prevention methods for these significant infectious diseases. Enhance your understanding of microbiology and public health.