Ophtho/Derm/Rheum-Micro

What areas does Hansen’s disease have the highest prevailence

Texas

Lousiana

Hawaii

Key organism characteristics of M. leprae

AFB

Obligate Intracellular

Grow in cooler temps(Mouse feet, Skin Lesions)

How is M. leprae transmitted?

Prolonged exposure to respiratory secretions

Children are more suseptible

Reservoirs: 9 banded Armidillo, Mouse Footpad

How is M.leprae diagnosed

Smear of Skin, Nasal, Ear or Secretions for AFB

Lepra Cells

Lepromin Test: lepromatous form will be negative

How do the tuberculoid and lepromatous forms of leprosy differ based on:

Lepromin Test

AFB Counts

Immune Response

Type of Damage

Lesion Types

Lepromin Test: Only positive in Tuberculoid

AFB Count: Low in Tuberculoid

Immune response: Th1 response in Tuberculoid

Type of Damage: Immune-meadiated in tuberculoid, but Direct bacterial in; Lepromatous

Lesions: Tuberculoid-Hyperpigmented Macules(plaques), Lepromatous-Nodular(Leonizing), Anesthetic lesions(Face and Fingers)

How is leprosy Treated

Tuberculoid: Dapsone and Rifampin

Lepromatous: Clofazimine and 2 others

What are some characteristics of Borrelia burgdorferi

Spirochete

OspA,OspB Antigens

Complex media required

What are the areas of the US the lyme’s disease is more prevailent in?

Northeast

Midwest

Northwest/N. Cali

What is the pathogenesis of B. burgdorferi transmition to humans

Ixodes dammini

Mammalian blood trigers Osp expression

Osp Disseminated organism in Tick(Saliva)

How does B. burgdoferi cause disease in  humans and what people exhibit worse forms of the disease?

Bystander Effect of activated Lymphs and Macs

HLA-DR4 and IgG to OSpA develop chronic disease

How does lymes disease typically present

Stage 1: “Bull’s Eye” Erythema Marginatum (painless) along with systemic signs

Stage 2: Multiple Annular Rashs, Cranial Nerve Palsy, Flu-like

Stage 3: After months untreated chronic Arthritis and Chronic Neurological problems develop

How do you diagnose Lyme’s

2 Step Serology

1)Elisa(Low specificity)

2)Immunoblot for Ab against burgdoferi protein if (+)Elisa

How is Lyme’s disease treated
Doxycycline or Amoxicillin
How is Relapsing Fever transmitted?

Epidemic(Not US)(B.recurrentis): Spread by Lice(Pediculus humanas Corporis or Capitis)

Endemic(Occurs in US)(Borrelia hermsii, Borrelia turicate): Spread by Soft Tick(Ornithodoros) which exhibit transovarily

What are the areas of increased prevailence of relapsing Fever

Epidemic Form: Not US

Endemic Form: Western US

What is the virulence of Borrelia organism that produces Relapsing Fever
Antigenic Variation
How does Relapsing Fever typically present?

Fever, Reticuloendothelial(Hepatosplenomegaly, Cardiac, Neurological Symptoms)

3-10 day remission

Recurrent Fever(2-3 Episodes)

How do you diagnose and treat Relapsing Fever

Dx: Blood Smear

Rx: Tetracycline or Erythromycin

Categories: Microbiology