Trichomonas vaginalis and other Ameba Infections Doç.Dr.Hrisi BAHAR.

Trichomonas vaginalisTrichomonas vaginalisand other and other

Ameba InfectionsAmeba Infections

Doç.Dr.Hrisi BAHAR

Trichomonas vaginalisTrichomonas vaginalis

Morphology and life cycleMorphology and life cycle

☻ TrophozoiteTrophozoite

Pear-shaped and actively motile, Pear-shaped and actively motile,

14-17 µm X 5-15 µm14-17 µm X 5-15 µm

An An undulating undulating membranemembrane

AxostyleAxostyle

Four anterior flagellaFour anterior flagella

A single A single nucleusnucleus

Four anterior Four anterior flagellaflagella

The single lateral The single lateral flagellum (the flagellum (the undulating membraneundulating membrane

Life cycleLife cycle

☻ Life cycleLife cycleThere is oThere is only trophozoite stage in nly trophozoite stage in life cyclelife cycle.. WomenWomen: vagina and urethra: vagina and urethra

TrophozoitesTrophozoites

Men:Men: urethra or prostate, urethra or prostate,

testes, epididymistestes, epididymis

☻ The infection is acquired by The infection is acquired by sexual sexual activityactivity or some or some indirect waysindirect ways

Only Only trophozoites in trophozoites in life cycle, no life cycle, no cyst stagecyst stage

The infective The infective stage isstage is trophozoitetrophozoite

The trophozoites The trophozoites multiply by multiply by binary fissionbinary fission

☻Trichomoniasis is a vaginal infections caused by T. vaginalis.

☻ This infection is among most common conditions in women attending reproductive health care centers.

EpidemiologyEpidemiology

☻ Most prevalent in age group 20-45.

☻Worldwide, over 180 million cases.

☻T. vaginalis accounts for 15-20% of all vaginitis.

EpidemiologyEpidemiology

Trichomonas vaginalisTrichomonas vaginalis

☻ The vagina is the most common site of infection in women, and the urethra (urine canal) is the most common site of infection in men.

☻ Women can acquire the disease from infected men or women, but men usually contract it only from infected women.

Signs and SymptomsSigns and Symptoms

Women:Women:

Signs and symptoms of infection range from having no symptomsno symptoms (asymptomatic) to very symptomaticto very symptomatic. Typical symptoms includeTypical symptoms include :

☻Foul smelling , pale yellow or gray-green discharge from the vagina

☻Vaginal itching or redness.


Other symptoms can includeOther symptoms can include ☻Lower abdominal discomfort

☻The urge to urinate

☻ The vaginal mucosa often is deeply erythematous.

☻ The cervix is friable and diffusely inflamed, sometimes covered with numerous petechiae ("strawberry cervix").


Men: ☻Urethritis and, more rarely, epididymitis or

prostatitis can develop in infected males

☻Most are asymptomatic.

☻Reinfection is common.

Trichomonas vaginalis is considered an important cofactor in amplifying human immunodeficiency virus transmission.

DiagnosisDiagnosis

☻ Finding trophozoitesFinding trophozoites

In women:In women: vaginal dischargevaginal discharge

In the male:In the male: urethral discharge , urethral discharge , prostates secretions, centrifuged urine.prostates secretions, centrifuged urine.

Methods:Methods: direct smear or culture direct smear or culture

T. T. vvaginalisaginalis Microscopic Diagnosis Microscopic Diagnosis

☻ Microscopy– Saline wet mount

50-60% sens in women,

30% sens in men, low specificity– Pap smear

50 % sensitivity, 90% specificit

Low PPV in low prevalence pop

T.T.vaginalis vaginalis Culture DiagnosisCulture Diagnosis

In-Pouch TVIn-Pouch TV

85-95% sens in women, >95% spec

60 % sens and high specificity in men

TT. vaginalis. vaginalis Antigen Detection Antigen Detection

OSOM Trichomonas Rapid Test (Genzyme Diagnostics, Cambridge, MA) ☻ 10 min point-of-care test

☻ 83.3% sensitive 98.8% specific vs. culture

☻(wet mount 71.4% sensitive)

TT. . vvaginalisaginalis Molecular Methods Molecular Methods

☻ PCR>90% sensitive and >95% specific for females

>90% sensitive and specific for malesCulture 70% sensitive vs. PCR

Recommended Treatment Recommended Treatment by CDCby CDC

☻ Metronidazole 2 g ………orally in a single dose OR

Tinidazole 2 g ……………orally in a single dose

Alternative Regimen

☻ Metronidazole 500 mg......... orally twice a day for 7 days

Patients should be advised to avoid consuming alcohol during treatment with metronidazole or tinidazole. Abstinence from alcohol use should continue for 24 hours after completion of metronidazole or 72 hours after completion of tinidazole.

Free Living AmebasFree Living Amebas

Free Living AmebasFree Living Amebas

Small free-living amebas belonging to the genera :

►► Acanthamoeba

►► Naegleria

occur world-wide .

AcanthamoebaAcanthamoeba spp spp

►► At least 5 species of Acanthamoeba have been identified in human tissues, this is one of the most common amebas in soil and freshwater.

►► Trophozoits occur only as amoeboid forms:


Trophozoits occur only as amoeboid forms:


Life Cycle Stages

Free-living trophozoites and cysts occur in both the soil and freshwater.

AcanthamoebaAcanthamoeba spp. spp.

These species cause 2 pathological effects

►► Granulomatous amebic meningoencephalitis.

►► Inflammation and opacity of the cornea.


Symptoms

►► Foreign body sensation, severe ocular pain, photophobia and blurred vision.

►► Often pain is more severe than signs in early course of the disease.


Most of these ocular infections were in contact lens wearers who used home-made saline water.

AcanthamoebaAcanthamoeba spp. spp.

Management

►► Early diagnosis a prognostic factor of

a successful outcome.

►► Topical anti-amoeba agents.

►► Penetrating keratoplasty in a severe

progressive keratitis.

Naegleria sppNaegleria spp

►► Free-living in freshwater and soil including thermal pools

►► They have even been isolated from bottled mineral water in Mexico.

Life cycle of NaegleriaLife cycle of Naegleria


►► N. fowleri is the only species of Naegleria genus that is pathogenic to humans

►► It lives in nature fresh water, lakes and ponds (especially warm water) .


Exists in 3 forms

►► Trophozoite invasive, reproductive form

(7- 20 µ m) which lives in temperatures from

35- 46 .C

►► Flagellate form ,do not divide

►► Resistant cyst form 7 -10 µm in size

Primary Amoebic Meningoencephalitis imary Amoebic Meningoencephalitis (PAM)(PAM)

►► Acute, suppurative infection of the brain and meninges caused by N. fowleri

►► First described in 1965 by R.F. Carter and M. Fowler in Australia

►► Usually affects immunocompetent children and young adults.


Epidemiology

►► N. fowleri has been isolated all over the world

►► As of 1997, approximately 200 cases have been reported worldwide with 81 cases in the US (primarily in central and southeast)

►► Risk factors: jumping/diving, IgA defic

►► Males/females =3/1

►► Mortality rate > 95%


Pathophysiology

►► Trophozoites penetrate the nasal mucosa

and the cribiform plate during inhalation or

aspiration of contaminated dust/water

►► The organisms migrate via the olfactory nerves to invade brain tissue

►► Enzymes are produced resulting in diffuse and

rapid hemorrhage and necrosis of the brain


Clinical manifestation ►► Indistinguishable from acute bacterial meningitis ►► Symptoms begin 2 -14 days from exposure►► Initially may notice change in taste/smell ►► fever, nausea, vomiting.►► Mental status changes seen in 66% ►► Myocarditis has been reported ►► Rapid progression with death occurring in 3-

7days-


Diagnosis

►► Lab studies reveal leukocytosis , hyperglycemia and glycosuria leukocytosis,

►► Molecular studies PCR/DNA probes under research


CT scan of head

►► Not diagnostic for PAM

►► May be normal early in disease

►► Later, may show signs of elevated leptomeningeal enhancement

Important notesImportant notes

►► Consider Naegleria when all studies point to bacterial meningitis but the gram stain is negative

►► Overall mortality is near 95% therefore you need a high index of suspicion

►► Plug your nose or wear nose clips when jumping into fresh water


Treatment

►► Amphotericin B is the mainstay of therapy

►► Successful outcomes are reported with high dose systemic and intrathecal ampho b.

►► Other adjunctive therapy includes miconazole and oral rifampin

►► New studies show that azithromycin may be a useful addition to therapy.

Trichomonas vaginalis and other Ameba Infections Doç.Dr.Hrisi BAHAR.

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