1. Spirochaetales and their diseases
Spirochaetaceae – Treponema
Treponema pallidum pallidum - Syphilis
T. pallidum endemicum - Bejel
T. pallidum pertenue - Yaws
T. pallidum carateum – Pinta
Spirochaetaceae – Borrelia
Borrelia burgdorferi – Lyme disease
Borrelia recurrentis – Relapsing fever
Leptospiraceae – Leptospira
Leptospira interrogans – Leptospirosis (Weil’s disease)

2. Syphilis
Caused by the spirochete Treponema pallidum subspecies pallidum
T. pallidum cannot be propagated in vitro on laboratory media and is grown in rabbit testicles
No animal model available for the study of syphilis
Humans are the only reservoir
Sexually transmitted disease
that must be reported
The primary lesions is a
chancre at the infection site

3. Time course of Syphilis infections
Incubation period: 3-90 days (median 21) after sexual contact
Primary lesion: heals within 3-6 weeks
Secondary lesions: appear 2-8 weeks after onset of primary lesions; can last several months
Latent syphilis: no clinical signs, treponemes in blood and tissues, relapses do occur; early latent syphilis (year 1 after infection) and late l.s. (thereafter)
Tertiary syphilis: more than five years
Treatment:  Benzathine penicillin G (one injection 2.4 million units i.m.) for primary, secondary or early latent syphilis. Three injections in weekly intervals for late latent syphilis or syphilis of unknown duration; β-lactam allergy: doxycycline

4. Clinical manifestations of primary syphilis
Primary lesion (chancre) develops at the site of inoculation
Progresses from macule to papule to ulcer
Ulcer typically painless, indurated, and has a clean base
Highly infectious, Treponemes can be isolated from the chancre
Chancre heals spontaneously within 3 to 6 weeks
Multiple lesions can occur
Regional lymphadenopathy: classically rubbery, painless, bilateral
Serologic tests for syphilis are not positive during primary syphilis; diagnosis requires direct detection of T.p. in primary lesion exsudate

5. Clinical manifestations of primary syphilis
Chancre on the tongue
Perianal chancre

6. Secondary syphilis
Clinical manifestations of secondary syphilis often occur as isolated symptoms
Rash (75%–100%)
Lymphadenopathy (50%–86%)
Malaise
Mucous patches (6%–30%)
Condylomata lata (10%–20%)
Alopecia (5%)
Liver and kidney involvement may occur
Splenomegaly is occasionally present
Serologic tests (treponemal and non-treponemal) are usually highest in titer during this stage; both tests are required to establish diagnosis.
Treponemes can be isolated from Condylomata lata

7. Secondary syphilis Papulosquamatous rash Papulosquamatous rash,
includes palms and soles
Condylomata lata

8. Secondary syphilis
Alopecia
Nickel & dime lesions

9. Condylomata lata during secondary syphilis

10. Latent syphilis Positive non-treponemal and treponemal serology
May occur between primary and secondary stages, between secondary relapses, and after secondary stage
Absence of clinical manifestations
CNS manifestations may be borderline
Early latent (≤12 months following transmission), late latent (>12 months)

11. Tertiary syphilis – outcome of untreated syphilis in the Oslo Study Also, recall infamous US-PHS study in Tusgekee, AL!
Symptoms at re-examination or death
% of Total
Neurosyphilis
9.5
Cardiovascular syphilis
12.8
Benign late syphilis
12.2
Latent syphilis
14.1
Spontaneous cure – seronegative
27.9
Died of syphilis (non cardio or CNS)
0.8
Died of some other cause
22.6

12. Neurosyphilis, now and then
During the pre-antibiotic era – one day with venus, the rest of your life with mercury (then the therapeutic of choice)…
1920s: ~10% of psychiatric hospital admissions were for neurosyphilis
1920s: ~ 20% of patients in mental institutions had neurosyphilis
: symptomatic early syphilis (within 12 months of infection) occurs predominantly in HIV positive MSM (men who have sex with men; 1.5% show signs of neurosyphilis): visual disturbance, new onset headaches, acute meningitis syndrome (fever and meningismus: clinical signs of meningitis with sterile blood and CSF cultures)
Treatment: aqueous crystalline penicillin G, million units per day, administered as 3-4 million units intravenously every 4 hours or by continuous infusion, for days

13. Clinical manifestations of neurosyphilis
Acute syphilitic meningitis
Meningovascular syphilis
Parenchymal neurosyphilis:
tabes doralis (spinal myelopathy) &
general paresis
Gummatous neurosyphilis
Ocular manifestations: keratitis, uveitis, chorioretinitis, retinitis, retinal vasculitis, optic nerve neuropathies (Argyll Robertson pupil)
Asymptomatic neurosyphilis (abnormal CSF only)
Ocular involvement can occur in early (≤12 months) or late neurosyphilis (≥12 months)
T. pallidum in brain tissue
Parenchymal neurosyphilis

14. Tertiary syphilis
Approximately 30% of untreated patients progress to the tertiary stage within 1 to 20 years
Rare because of the widespread availability and use of antibiotics
Manifestations: Gummatous lesions & Cardiovascular syphilis (aneurysims)
Gumma
Syphilitic aneurysm

15. Syphilis—reported cases by stage of infection in the United States, 1941–2011

16. Primary and secondary syphilis—rates by state: United States, 2011

17. Congenital syphilis
Definition: Transplacental transmission of T.p. occurs only after 18 weeks of gestation; disease is predicated on the immunological status of the mother and her pathogen load (T. pallidum)
Stillbirth (high load)
Early congenital syphilis (intermediate load): premature birth with hepatosplenomegaly, skeletal abnormalities, pneumonia and bullous skin disease (pemphigus syphiliticus), rhinitis (snuffles), rhagades (linear scars at mouth)
Late congenital syphilis (lower load): occurs >2 yoa, Hutchinson’s teeth (notched incisors), keratitis, deafness, saddle nose, sabre shins, short maxillae, protruding mandible
Prevention: penicillin treatment before or during 16 weeks of pregnancy
Treatment: penicillin; developmental defects permanent

18. Congenital syphilis Syphilitic pemphigus Hepato- splenomegaly
Sabre shin tibia
Snuffles & rhagades
Hutchinson’s teeth

19. Epidemiology of congenital syphilis

20. Diagnosis of syphilis
Detection of T.p. in primary lesion exsudate: darkfield microscopy, fluorescence antibody test (DFAT-TP), (PCR not CDC recommended); positive test is diagnostic!
Non-treponemal tests: VDRL (Veneral Disease Research Laboratory) and RPR (Rapid Plasma Reagin) are used for screening (positive after 8 weeks); they detect cardiolipin-specific antibodies and yield false positives; cannot establish the diagnosis; useful to monitor therapy and disease progression
Treponemal tests: FTA-ABS (Fluorescent Treponemal Antibody Absorption Test), TP-PA (Treponema pallidumParticle Agglutination Assay), EIA (Enzyme Immuno Assay) detect antibodies against T. pallidum; when infected they remain positive for life and confirm the diagnosis; multiple tests give information on pathogenesis
Prenatal screening (first visit and third trimester repeat) is essential to prevent congenital syphilis
Darkfield microscopy
DFAT-TP

21. There was a young man from Back Bay
Who thought syphilis just went away
He believed that a chancre
Was only a canker
That healed in a week and a day.
But now he has “acne vulgaris”—
(Or whatever they call it in Paris);
On his skin it has spread
From his feet to his head,
And his friends want to know where his hair is.
There's more to his terrible plight:
His pupils won't close in the light
His heart is cavorting,
His wife is aborting,
And he squints through his gunbarrel sight.
Arthralgia cuts into his slumber;
His aorta is in need of a plumber;
But now he has tabes,
And sabershinned babies,
While of gummas he has quite a number.
He's been treated in every known way,
But his spirochetes grow day by day;
He's developed paresis,
Has long talks with Jesus,
And thinks he's the Queen of the May.
Anonymous, 1920s

22. Countries reporting Yaws (purple), Bejel (blue) and Pinta (orange)

23. Yaws
T. pallidum spp. pertenue is transmitted by contact with Yaws lesion exsudate through cutaneous lesions to a new host; 75% in children (6-10 yoa)
Incubation 3-5 weeks, papules that erode, disseminate all over the skin and heal within 6 months (primary lesions)
Weeks to months later, secondary lesions erupt reiteratively over five years; lymphadenopathy, osteitis and periosteitis common
Late stage lesions: cutaneous plaques, nodules and ulcers, hyperkeratoses of the palms and soles, and gummatous lesions
Diagnosis: dark field microscopy of primary or secondary lesion exsudate; VDRL positive
Therapy: penicillin G; epidemiology: WHO estimates 300,000 cases in tropical Africa and Asia

24. Pinta
T. pallidum spp. carateum is transmitted by contact with Pinta lesion exsudate through cutaneous lesions to a new host
Incubation 7-21 days, small, erythematous, pruritic papules enlarge and become slightly squamous, and coalesce with surrounding lesions
Primary lesions persist for several years before healing with residual hypopigmentation
Disseminated lesions (pintids) appear 3 to 12 months after the initial lesions develop into dyschromic brown, gray, or blue lesions
Diagnosis: dark field microscopy of primary or secondary lesion exsudate; VDRL positive
Therapy: penicillin G; WHO estimates a few hundred cases in Central and South America

25. Bejel (endemic syphilis)
T. pallidum spp. endemicum is transmitted by direct contact, eating and drinking utensils
Primary lesions are rarely observed
Secondary lesions consist of oropharyngeal mucous patches, split papules at the corners of the mouth, condylomata lata, periostitis, and regional lymphadenopathy
Gumma or neurological manifestions are uncommon
Diagnosis: VDRL positive
Therapy: penicillin G; precise incidence not known

26. Lyme disease Caused by tick bite transmission of Borrelia burgdorferi
About 36,000 cases per year in the United States
Early localized stage: (3-30 days post tick bite): erythema migrans (EM or bull’s eye, 70-80%), fatigue, chills, fever, headache, muscle and joint aches, and swollen lymph nodes
Early disseminated stage (days to weeks): generalized rash, facial (Bell’s) palsy, headaches, nuchal rigidity, shooting pain, Lyme carditis (AV block); symptoms typically resolve even without therapy
Late disseminated stage (months to years): intermittent bouts of arthritis, severe joint pain and swelling (60%); neurological symptoms (5% - shooting pains, numbness, short-term memory loss)

27. Lyme Disease
Arthralgia
Erythema migrans
Bell’s palsy
Lyme carditis

28. Lyme diseases cases reported in the United States, 2012
The blacklegged tick (or deer tick, Ixodes scapularis) spreads the disease in the northeastern, mid-Atlantic, and north-central United States. The western blacklegged tick (Ixodes pacificus) spreads the disease on the Pacific Coast.

29. Enzootic life-cycle of Borrelia burgdorferi in Ixodes ticks
The enzootic cycle of Borrelia burgdorferi. Ixodes spp. ticks undergo a three-stage life cycle — larva, nymph and adult — with one blood meal per stage. Although some Borrelia spp. that cause relapsing fever can be passed from adult to egg (transovarial transmission), this does not occur with B. burgdorferi, so each generation of tick must acquire a B. burgdorferi infection anew. Larval ticks feed on many different animals, including Peromyscus spp. mice, squirrels and birds. B. burgdorferi infection is acquired by feeding on an infected reservoir animal, and the bacterium is retained during the subsequent stages (that is, trans-stadially) after each blood meal and moult. Nymphs feed on a similar range of hosts to larvae; transmission of spirochaetes to a competent reservoir host by a feeding nymph perpetuates the enzootic cycle for the next generation of larval ticks. Although small mammals are usually thought of as the primary reservoirs for Lyme disease spirochaetes, studies have called attention to the importance of migratory birds as disseminators of spirochaetes over large distances. Adult ticks are not generally important for maintenance of B. burgdorferi in the wild, as they feed predominantly on larger animals such as deer, which are incompetent hosts for B. burgdorferii. However, deer are important for maintenance of the tick population because adult ticks mate on them. Although all three stages of Ixodes scapularis can feed on humans, nymphs are responsible for the vast majority of spirochaete transmission to humans. It is unknown whether infected humans can transmit spirochaetes to feeding larvae, and humans are generally considered dead-end hosts and not part of the enzootic cycle. Dogs are probably incidental hosts and not part of the enzootic cycle.

30. Architecture of Borrelia burgdorferi
a | Freeze-fracture electron micrographs showing the convex and concave leaflets of the inner and outer membranes (IM and OM, respectively). Integral membrane proteins (particles) are considerably more abundant in the IM; the density of OM particles is much lower than that in a prototypical Gram-negative bacterium. Scale bars represent 500 nm. b | Cryoelectron tomograms of the ends of borrelial cells showing IM, OM, peptidoglycan (PG), flagellar motor and filament assemblies (FMFA), chemoreceptor arrays (CR) and an external layer comprising outer-surface lipoproteins (Osps). Upper scale bar represents 1 μm, lower scale bar represents 100 nm. c | Cryoelectron tomographic cross-section showing the IM, OM, periplasmic space (PS) and periplasmic flagella (PFs). Scale bar represents 50 nm. d | Longitudinal cryoelectron tomographic slice showing a ribbon of nine flagellar filaments wrapping around the IM in a right-handed helix. Scale bar represents 200 nm.

31. The envelope of Borrelia burgdorferi
Schematic of the borrelial cell envelope shows the outer membrane, flagellar filaments, peptidoglycan, and cytoplasmic inner membrane. The outer membrane contains outer-surface lipoproteins (Osps) in high density and β-barrel outer-membrane-spanning proteins such as BamA in low density. The inner membrane is rich in integral membrane proteins, many of which are transporters. BbCRASP, complement regulator-acquiring protein; OppA1, oligopeptide permease A1; PTS, phosphotransferase system.

32. The tick-mammal interface
The tick creates a feeding pit with its mouthparts, using its hypostome (a barbed protuberance) as an anchor to the skin of its host. Initial salivary secretions form a cement cone around the hypostome that further anchors the tick during feeding. Subsequently, the tick produces copious amounts of saliva containing a plethora of bioactive agents that Borrelia burgdorferi exploits to help establish infection. The diagram shows just a few of these bioactive agents, including SALP15 (which binds to the spirochaetes and inhibits killing of the bacteria and T cell priming) and sialostatin L (which blocks neutrophil chemotaxis). A group of borrelial surface lipoproteins, collectively referred to as BbCRASPs (complement regulator-acquiring surface proteins), bind complement factor H, preventing activation of the alternative complement pathway. B. burgdorferi cells are recognized by innate immune effector cells such as dendritic cells (DCs), neutrophils and macrophages, initially via surface-exposed pattern recognition receptors; activation of these cells increases following internalization and degradation of spirochetes within phagolysosomes. DCs that have taken up spirochetes migrate to the lymph nodes, where they present processed borrelial antigens to T cells and B cells. Sensitized T cells enter the circulation and are recruited to the site of infection. Plasma cells secrete specific antibodies that can kill B. burgdorferi via complement-dependent and –independent pathways. Production of pro-inflammatory cytokines by activated macrophages results in the recruitment of additional neutrophils, T cells, macrophages and DCs to the bite site, and eventually the development of erythema migrans. OspC, outer surface lipoprotein C; TLR, Toll-like receptor.

33. Diagnosis and therapy of Lyme disease
Diagnosis step 1: CDC recommends a two-step FDA approved laboratory testing for Lyme disease; first, EIA (enzyme immunoassay, either ELISA or ELFA) for B. burgdorferi specific antibodies. Highly sensitive, not absolutely specific. If negative and clinical disease does not progress, no further test. Alternatively, repeat EIA at a later time.
Diagnosis step 2: If positive, immunoblot (Western blot) to detect B. burgdorferi specific antibody (>30 days of symptoms, IgG; ≤30 days, IgM and IgG immunoblot).
Positive Western blot
Other commercially available assays not approved by FDA!
Treatment of uncomplicated Lyme disease: oral doxycycline, ampicillin or cefuroxime axetil for 2-4 weeks.
Treatment of patients with neurological or cardiac forms of Lyme disease: intravenous ceftriaxone or penicillin G

34. Prevention of Lyme disease
Antibiotic prophylaxis with doxycycline (diminishes incidence by 87%) following tick bites; however, tick bites are often missed.
Protective measures to avoid tick bites in endemic areas: clothing, insect repellent (DEET=N,N-diethyl-m-toluamide), tick inspection and removal (36h before Ixodes ticks bite).
Lymerix® vaccination. Three immunizations with purified OspA prevent transmission in 79% of vaccinees and therefore disease following tick bite.
Lymerix, FDA licensed 1998, was withdrawn by GSK (2001) following community concerns over vaccine safety: local soreness, redness, or swelling as well as myalgias, fever, or chills for three days

35. Relapsing fever Distinguish louse-(B
Relapsing fever Distinguish louse-(B. recurrentis) and tick-borne (15 Borrelia spp.) relapsing fever
Louse RF transmitted by the human body louse (Pediculus humanus) whose gut is infected with Borrelia recurrentis; large outbreaks during war & famine, none in the US
Louse RF transmission requires crushing of infected lice and inoculation of Borrelia into the bite wound. Louse RF typically causes only one fever relapse.
Tick RF is transmitted by the bite Ornithodoros ticks that have been infected with Borrelia spp: 504 cases ( in 12 Western States (80% CA & WA).
Acute fever episodes (3-5 day) with rigors, headache, myalgias, arthralgias, lethargy, photophobia (iritis), and cough (pneumonia), petechiae, hepato/splenomegaly; 5-7 day remission. Mortality of untreated disease=40%
Diagnosis: blood culture isolation of Borrelia; Proteus OXK positive (VDRL/Lyme disease serology positive in 5%)
Treatment: Tetracycline, penicillin or erythromycin

36. Leptospirosis CDC NNDSS notifiable disease since 2013
Definition: Zoonotic disease caused by Leptospira interrogans that is disseminated by animal urine (domesticated (dogs) and wild animals); at risk: farmers, miners, sewer and slaughterhouse workers, veterinarians, athletes in contact with contaminated water
Transmission: contact with animal body fluids or contaminated water; cases in the US (50% in Hawaii)
Incubation period 2d-4 weeks (median 7d)
First phase (with fever, chills, headache, muscle aches, vomiting, or diarrhea); patient may recover for a time
Second phase (Weil’s disease): jaundice, red eyes, abdominal pain, rash, kidney or liver failure, meningitis; last ≥3 weeks
Diagnosis: culture or IF detection of L. interrogans in patient; 4x increase or ≥800 L. interrogans serum agglutination titer; positive PCR in patient sample
Treatment: doxycycline or penicillin

37. Clinical presentation of Leptospirosis

38. Jarisch-Herxheimer Reaction
Adolf Jarisch
Karl Herxheimer
Originally discovered during treatment of syphilis patients with mercury or salvarsan
Systemic reaction in spirochete infected patients treated with an effective antibiotic; typically J.-H. reaction is most severe with penicillin therapy (1-2 hours after injection)
Abrupt onset of fever, chills, myalgia, headache, tachycardia, hyperventilation, vasodilation with flushing, mild hypotension
Caused by the release of endotoxin (LPS) released from killed spirochetes