Andrews

1
Andrews Chapter 20pgs 526-547

• JoAnne M. LaRow, D.O.
• December 9, 2003

2
Phylum Protozoa

• One-celled organisms
• Divided into classes according to nature of
  locomotion
• Class Sarcodina move by temporary projections of
  cytoplasm (pseudopods)
• Class Mastigophora by means of one or more
  flagella
• Class Ciliata by short, hair-like projections of
  cytoplasm (cilia)
• Class Sporozoa with no special organs of
  locomotion

3
Class Sarcondina

• Best known organism in class ameba
• Entamoeba histolytica is ameba of medical
  significance
• Amebiasis cutis begins as deep abscesses that
  rupture
• These form ulcerations with distinct, raised,
  cordlike edges and an erythematous halo approx.
  20 cm wide
• Base is covered with necrotic tissue and
  hemopurulent, glairy, pus-containing amebae

4

• Multiple large ulcers
• Extensive tissue destruction
• Resembles pyoderma gangrenosum

5
Amebiasis Cutis

• Lesions may occur on trunk, abdomen, external
  genitalia, buttocks, or perineum
• Abdominal lesions may arise from hepatic
  abscesses
• All ages are at risk
• Intestinal amebiasis, with bloody diarrhea and
  hepatic abscesses, may be present
• Chronic urticaria may be sole manifestation of
  early amebiasis
• Organism may be found at base of lesion by direct
  smear or shave bx

6
Histology-Amebiasis

• Necrotic ulceration with many lymphocytes,
  neutrophils, plasma cells, and eosinophils
• E. histolytica is found in tissue, within blood
  and lymph vessels
• Organisms measures 50-60 microns in diameter
• Has a basophilic cytoplasm, a single eccentric
  nucleus with a central karyosome

7
Diagnosis Amebiasis

• Organism is frequently demonstrable in fresh
  material from base of ulcer
• Indirect hemagglutination test results remain
  elevated for yrs after initial invasive disease
  onset
• Whereas, results of gel diffusion precipitation
  tests and counterimmunoelectrophoresis become neg
  at 6 months
• This property can be used to test for recurrent
  or active disease in persons coming from endemic
  areas

8
Tx-Amebiasis

• Recommended is Metronidazole 750 mg orally TID
  for 10 days, followed by iodoquinol 652 mg TID
  for 20 days
• Surgical drainage for abscesses

9
Class Mastigophora

• Organisms are known as flagellates
• Many have undulating membrane with flagella along
  crest

10
Trichomoniasis

• Trichomonas vulvovaginitis is a common cause of
  vaginal pruritis with burning and frothy
  leukorrhea
• Vaginal mucosa appears bright red from
  inflammation and may be mottled with
  pseudomebranous patches
• Males may harbor organism and develop urethritis
  and prostatitis, and occasionally balanoposthitis
• Neonates may acquire infection during passage
  through birth canal, but require tx only if
  symptomatic or if colonization lasts more than 4
  weeks
• However, as this is otherwise nearly exclusively
  a sexually transmitted disorder, trichomonas
  vulvovaginitis in a child should make one suspect
  sexual abuse

11
Trichomonas

• Tx Metronidazole 2.0 g in single oral dose TOC
• Alternatively, 500 mg twice daily for 7 days may
  be given
• Warn pts not to drink alcohol for 24 hrs after
  last dose because disulfiram type of effects of
  this med
• Male sex partners should be tx
• Metronidazole is contraindicated in pregnant
  women-use clotrimazole intravaginally

12

• Colorless pyriform flagellate 5-15 microns long
• Demonstrated in smears from affected areas
• DIF is sensitive and specific

13
Leishmaniasis
14
Leishmaniasis

• Three forms
• A.) cutaneous form restricted to skin
• B.) mucocutaneous form affects both skin and
  mucosal surfaces
• C.) visceral leishmaniasis that affects organs of
  reticulo-endothelial system

15
Leishmaniasis

• Cutaneous leishmaniasis, American mucocutaneous
  leishmaniasis, and visceral leishmaniasis
  (kala-azar), which includes infantile
  leishmaniasis and post-kala-azar dermal
  leishmaniasis, are all caused by morphologically
  and culturally indistinguishable protozoa of the
  family Trypanosomidae, called Leishmania

16
Cutaneous Leishmaniasis

• Several types of lesions
• All tend to occur on exposed parts as all are
  transmitted by the sandfly

17
Pathogenesis

• Organisms are obligate intracellular parasites
  existing in two forms promastigote and
  amastigote
• In gut organisms multiply as extracellular
  flagellated promastigotes
• Following migration to the proboscis, parasites
  are inoculated (in promastigote form) via sandfly
  bite
• These transform into amastigotes within cells of
  the reticuloendothial system in host- be it
  human, rodent or canine

18
Life Cycle
19
Old World Leishmaniasis

• Limited to the skin
• Called Baghdad boil, oriental sore, leishmaniasis
  tropica, birskra button, Delhi boil, Aleppo boil,
  Kandahar sore, Lahore sore
• May present in two ways moist or rural type, a
  slow growing, indurated, livid, indolent papule
  which enlarges in a few months to form an ulcer
  as much as 5 cm in diameter
• Spontaneous healing takes place within 6 months,
  leaving a characteristic scar
• Contracted from rodent reservoirs such as gerbils
  via the sand fly as vector
• Short incubation period-1-4 weeks

20
(No Transcript)
21
(No Transcript)
22

• Bagdad boil of 5 months duration

23
Old World Leishmaniasis

• Dry or urban type
• Has a longer incubation period (2-8 months or
  longer)
• Develops more slowly, and heals more slowly than
  the rural type

24
Leishmaniasis Recidivans

• Rarely, after initial or mother lesion heals,
  there may appear at the borders of healed areas a
  few soft red papules covered with scales and
  having the apple jelly characteristics of lupus
  vulgaris
• These spread peripherally on an erythematous base
  and are called lupoid type
• Aka leishmaniasis recidivans
• Occurs most commonly with urban type caused by L.
  tropica

25
(No Transcript)
26
New World Leishmaniasis

• Subtypes present of purely cutaneous involvement
  are uta, pain bois, and bay sore or chiclero
  ulcer
• Primary papule may become nodular, verrucous,
  furuncular, or ulcerated, with an infiltrated red
  border
• Subcutaneous peripheral nodules, which eventually
  ulcerate, may signal extension of disease
• A sporotrichoid pattern may occur with
  lymphadenopathy, and nodes may rarely yield
  organisms
• Recidivans lesions are unusual in New World form
  of disease

27

• American cutaneous leishmaniasis
• Lesion of localized cutaneous leishmaniasis
  presenting as an indurated nodule with an
  ulcerated crateriform center

28

• Cutaneous leishmaniasis
• A well circumscribed ulcerated lesion on the face
  of a child

29

• Cutaneous leishmaniasis
• Multiple ulcerated lesions on the legs of a rural
  worker

30

• Circular scars at previous sites of cutaneous
  leishmaniasis
• Often only sign of a previous infection

31
Chiclero Ulcer

• In Yucatan and Guatemala, a subtype of New World
  disease exists the chiclero ulcer
• Most frequently site of infection is the ear
• Lesions ulcerate and occur most frequently in
  workers who harvest chicle for chewing gum in the
  forests, where there is high humidity
• This form is a more chronic ulcer that may
  persist for yrs, destroying ear cartilage and
  leading to deformity
• Etiologic agent is L. mexicana and the vector, a
  sandfly, Lutzomyia flaviscutellatta

32
(No Transcript)
33
Uta

• Uta is a term used by Peruvians for leishmaniasis
  occurring in mountainous territory at elevations
  of 1200 to 1800 meters above seas level
• Ulcerating lesions are found on exposed sites,
  and mucosal lesions do not occur

34
Disseminated Cutaneous Leishmaniasis

• May be seen in New and Old World disease
• Multiple nonulcerated papules and plaques
• Chiefly on exposed surfaces
• Caused by several subspecies of L. mexicana
• L. aethiopica be etiology in Ethiopia and Kenya
• Begins with a single ulcer, nodule, or plaque
• Satellite lesions may develop cover entire
  body
• Disease is progressive and tx ineffective
• Characterized by anergy to organism
• Montenegro rxn is negative

35

• Disseminated cutaneous leishmaniasis

36
Epidemiology

• Cutaneous leishmaniasis is endemic in Asia Minor
  to a lesser extent in many countries around the
  Mediterranean Sea
• Iran and Saudi Arabia have a high occurrence rate
• Purely cutaneous lesions are found in Central and
  South America 9 pts who acquired their disease
  in Texas have been reported
• Children are affected most often, since immunity
  is acquired from initial infection
• Deliberate inoculation on thigh is sometimes
  practiced so that scarring on face- a frequent
  site for Oriental sore-may be avoided

37
Pathogenesis

• Organism has an alternate life in vertebrate and
  an insect host
• Man and other mammals such as dogs and rodents
  are the natural reservoir hosts
• Host vectors are Phlebotomus sandflies in Old
  World type and Phlebotomus perniciosus
  Lutzomyia sandflies for the New World cutaneous
  leishmaniasis
• After insect has fed on blood, the flagellates
  (leptomonas, promastigote) develop in gut in 8-20
  days, after which migration occurs into the mouth
  parts from here transmission into humans occurs
  by a bite
• In humans, flagella are lost and a leishmanial
  form (amastigote) is assumed

38
Histopathology

• Typical features of an ulcer heavy infiltrate of
  histiocytes, lymphocytes, and a polymorphonuclear
  leukocytes
• Numerous organisms are present ( mostly in
  histiocytes), which are nonencapsulated and
  contain a nucleus and a paranucleus
• Wrights, Giemsa, and monoclonal antibody
  staining may be helpful in identifying the
  organisms
• Parasitized histiocytes form tuberculoid
  granulomas in dermis
• Pseudoepitheliomatous hyperplasia may occur in
  edges of ulcer

39

• Localized cutaneous leishmaniasis a diffuse
  infiltrate extends into the subcutis
• Epidermis is ulcerated

40

• Mixed cell infiltrate with many plasma cells and
  neutrophils but with histiocytes predominating
• Organisms are seen within the histocytes

41
Diagnosis (contd)

• More sophisticated tests to diagnose and classify
  subspecies involve detection of monoclonal
  antibodies with immunoperoxidase, radiolabeling,
  or fluorescenation, DNA probes, DNA buoyancy,
  restriction-endonuclease fragment patterns of
  kenetoplast DNA, restriction-frequent length
  polymorphisms of unclear DNA, and isoenzyme
  electrophoresis

42
Montenegro skin test

• Uses leishmanial antigen to induce a
  cell-mediated response
• Can be used as a diagnostic method
• Cannot distinguish between past present
  infections
• Skin tests can be false-neg in anergic pts with
  disseminated infections

43
Diagnosis

• Demonstration of organism in smears
• Parasites can be cultured from tissue fluid
• A hypodermic needle is inserted into normal skin
  and to edge of ulcer base
• Needle is rotated to work loose some material and
  serum, which is then aspirated
• Culture on Nicolle-Novy-MacNeal (NNN) medium at
  22 degrees- 35 degrees C
• Leishmanin intradermal test may be helpful in
  nonendemic areas (Leishman-Montenegro-Donovan)
• It becomes positive 3 months after infection

44
Treatment

• Spontaneous healing occurs, usually within 12-18
  months, shorter for Old World disease
• Rationale for tx an ordinarily self-limited
  infection include avoiding disfiguring scars in
  exposed areas, avoiding secondary infection
  controlling disease in the population and
  failure of spontaneous healing in diffuse
  cutaneous and recidivans types, disease may
  persist for 20-40 yrs if untreated

45
Tx (contd)

• In areas which localized cutaneous leishmaniasis
  is not complicated by recidive or sporotrichoid
  forms or mucocutaneous disease, tx with topicals
  Paromycin sulfate 15 plus methylbenzethonium
  chloride 12
• Ketoconazole cream under occlusion,
• Cryotherapy, local heat, and laser ablation, or
  with intralesional sodium stibogluconate antimony
  or emetine hydrochloride, may be effective and
  safe
• Perilesional injections of interferon-gamma have
  also been reported to be effective but are
  expensive

46
Tx (contd)

• In pts who are immunocompromised or who acquire
  disease in areas where mucocutaneous disease may
  occur, systemic therapy is recommended
• Many alternatives reported effective
• Sodium antimony gluconate (sodium stibogluconate)
  solution given IV or IM-20mg/kg/day in two
  divided doses for 28 days
• Repeated courses may be given
• Antimony n-methyl glutamine (Glucantime) is used
  more often in Central and South America because
  of its local availability
• Ketaconazole (600mg/day for 28 days),
  itraconazole, dapsone, rifampin, and allopurinol

47
Tx (contd)

• Some of these have not been subjected to control
  trials, as is true of most topical treatments
• Recidive and disseminated cutaneous types may
  require prolonged courses or adjuvant interferon
  therapy
• Amphotericin B may be used in antimony-resistant
  disease
• Control depends on success of anti-fly measures
  taken by health authorities

48
Mucocutaneous Leishmaniasis (Leishmaniasis
Americana, Espundia)

• Infection occurs at site of fly bite
• Initially a destructive ulcer
• Secondary lesions on the mucosa occur at the same
  time or sometime during the next 5 yrs
• Earliest mucosal lesion is hyperemia of nasal
  septum with subsequent ulceration
• Ulceration progresses to invade septum and later
  paranasal fossae
• Perforation of septum eventually takes place
• Nose remains unchanged externally, despite
  internal destruction

49
Clinical Features

• Initially only dry crust is observed, or a bright
  red infiltration or vegetation on nasal septum
• Symptoms are obstruction and small hemorrhages
• Despite mutilation and destruction it never
  involves nasal bones
• When septum is destroyed, nasal bridge and tip
  of nose collapse, giving an appearance of a
  parrot beak, camel nose, or tapir nose
• Four of the great chronic infections (syphilis,
  tuberculosis, leprosy, and leishmaniasis) have a
  predilection for the nose
• Ulcer may extend to lips and continue to advance
  to pharynx, attacking soft palate, uvula,
  tonsils, gingiva, tongue

50

• Leishmaniasis americana (mucocutaneous)

51

• Eventual mutilation is called espundia
• Two perpendicular grooves at union of osseous
  palate and soft tissues, in mist of vegetative
  infiltration of the entire pharynx is called the
  palate cross of espundia
• Only in exceptional cases does American
  leishmaniasis invade genital or ocular mucous
  membranes
• Frequency of mucous membrane involvement is
  variable
• In Yucatan and Guatemala it is an exception
• In other countries such as Brazil, it may occur
  in 80 of cases

52
Epidemiology

• Mucocutaneous leishmaniasis is predominantly a
  rural and jungle disease
• It predominates in damp and forested regions
• Can be contracted at any time of the year-risk is
  highest just after the rainy season
• Affects all ages and races and both sexes are
  equally affected

53
Histopathology

• In cases of granulomatous infiltration, when
  intracellular parasites are found in histiocytes,
  leishmaniasis is one of several disease to
  consider
• Others are rhinoscleroma, histoplasmosis,
  granuloma inginale, and toxoplasmosis
• Leishman-Donovan body is nonencapsulated and
  shows a characteristic nucleus and parabasal body
• Touch smears stained with Giemsa are helpful in
  may cases of cutaneous and mucocutaneous
  leishmaniasis

54
Lab Findings

• Leishmania is demonstrated in cutaneous and
  mucous membrane lesions by direct smears or
  cultures
• Bx stained with Wrights stain intracellular and
  extracellular organisms with typical morphology
  or two chromatic structures nucleus parabasal
  body
• In later mucosal lesions there are less parasites
  making ID difficult
• Cx via NNN medium is useful
• Intradermal Montenegro test is performed
• A suspension of 0.1-0.2 ml injected intradermally

55
Lab Findings

• A reading is made 48-72 hrs later
• Positive rxn is an area of induration greater
  than 5 mm in diameter 24-48 hrs after injection
• Test is specific and sensitive, 95 positive
  results
• But can be neg in early cases of disease
• But it is easy to find the parasites
• Cross rxns occur with certain forms of TB, but
  are rare

56

• Montenegro test in leishmaniasis

57
Treatment-Mucocutaneous

• Same as described for cutaneous leishmaniasis
  except that antimony resistance is common
• Combination therapy using antimonials with other
  drugs like rifampin
• Or adding immunomodualtors such as interferon
  gamma or interleukin-2 may result in cure
• Amphotericin B tx may be needed

58

• Mucocutaneous leishmaniasis

59

• Leishmaniasis infiltrated dry inflammatory
  plaques of leishmaniasis in a woman from Italy

60

• Spectrum of American cutaneous leishmaniasis

61

• Disseminated leishmaniasis multiple erythematous
  plaques with scale-crust

62
Visceral Leishmaniasis (Kala-Azar,Dumdum Fever)

• Earliest lesion is cutaneous nodule or
  leishmanioma
• Occurs at site of initial sandfly inoculation
• Kala-azar means black fever
• Acquired its name because of patchy macular
  darkening of skin caused by deposits of melanin
  these develop later on in disease
• Patches are most marked over forehead and
  temples, periorally, and on midabdomen

63

• Nodules of various sizes
• Some pedunculated
• Pt has been tx for kala-azar over 6 month period
  over 20 yrs ago

64
Visceral Leishmaiasis

• Primary target for parasite is reticuloendothelial
  system spleen, liver, bone marrow, and lymph
  nodes
• Incubation period 1-4 months
• And intermittent fever,temps ranging from 39
  degrees- 40 degrees ushers in the disease
• Hepatosplenomegaly, agranulocytosis, anemia
  thrombocytopenia
• Chills, fever, emaciation, wt loss, weakness,
  epistaxis, and purpura develop
• Susceptibility to secondary infection may produce
  pulmonary and GI infection, ulcerations in the
  mouth (crancrum oris), and noma
• Death occurs in 2 yrs if untreated

65
Etiology

• L. donovani spp. Donovani, infantum, chagasi
• These are parasite of rodents, canines, and
  humans
• They are nonflagellate oval organisms 3 microns
  in diameter, known as Leishman-Donovan bodies
• In the sandfly it is a leptomonad form with
  flagella

66
Diagnosis

• Leishman-Donovan bodies may be present in
  individuals with kala-azar of India
• Specimens for examination in descending order of
  utility spleen pulp, sternal marrow, liver
  tissue, and exudate from lymph nodes
• Culture on NNN medium may also reveal organisms
• The intradermal Montenegro test is also reliable
• For tx general support measures pentavalent
  antimony is drug of choice

67
Post-Kala-Azar Dermal Leishmanoid

• In kala-azar leishmanoid forms (amastigote) may
  be widely distributed throughout apparently
  normal skin
• During after recovery a special form of dermal
  leishmaniasis known as post-kala-azar dermal
  leishmanoid appears
• Condition appears during or shortly after tx in
  African form
• Appearance may be delayed up to 10 yrs after tx
  in Indian form
• It is common in India, occurring in up to 20 of
  pts in Africa only 2 develop it

68
Post-Kala-Azar Dermal Leishmanoid

• Two constituents of eruption a macular,
  de-pigmented eruption found mainly on face, arms,
  and upper part of trunk a warty, papular
  eruption in which amastigotes can be found
• Pts may act as a chronic reservoir of
  infection-it may persist for up to 20 yrs
• Condition closely resembles leprosy
• Evidence that pts who will develop this have a
  marker interleukin-10 in their keratinocytes and
  sweat glands

69

• Post kala-azar dermal leishmaniasis

70
Vicerotropic Leishmaniasis

• 1 report of 8 soldiers developing systemic
  infection with L. tropica while fighting in
  Operation Desert Storm in Saudi Arabia
• None had symptoms of kala-azar, but 7 had fever,
  fatique, malaise, cough, diarrhea, or abdominal
  pain
• 1 pt was aymptomatic
• None had cutaneous disease
• In 7 diagnostic tests were pos. via bone marrow
  aspiration and 1 via lymph node aspiration
• 5 of 6 txd with sodium stibogluconate improved

71
Human Trypanosomiasis

• Three species are pathogenic to humans
  Trypanosoma gambiense and T. rhodesiense in
  Africa T. cruzi in America
• Early stages of African trypanosomiasis a chancre
  may occur at site of tsetse fly bite
• Next erythema with circumscribed swellings of
  angioedema, enlargement of lymph glands, fever,
  malaise, headache, and joint pain occurs
• In West African (Gambian) form, illness is
  chronic over yrs with progressive deterioration
• In East African (Rhodesian) form illness is acute
  with a stormy, fatal course of weeks to months

72
(No Transcript)
73
Chagas disease

• Reduviid bug (kissing bug, assassin bug) usually
  bites at night, frequently at mucocutaneous
  junctions, where bugs infected feces are
  deposited when it feeds

74
(No Transcript)
75
American Trypanosomiasis

• Unsuspecting sleeping person rubs the feces into
  the bite and becomes infected
• If bite occurs around the eye Romanas sign
  develops this consists of unilateral
  conjunctivitis and edema of eyelids, with an
  ulceration or chagoma in area
• Bite becomes markedly swollen and red whether
  trypanosomes are involved or not
• Acute Chagas disease is usually mild with fever,
  malaise, edema of face and lower extremities and
  generalized lymphadenopathy

76
Chagas Disease

• Prevalent in Central and South America from the
  U.S. to Argentina and Chile highest incidence is
  Venezuela, Brazil, Uruguay, Paraguay, and
  Argentina
• Approx. 29 of all male deaths in 29-44 yr age
  group in Brazil are ascribed to Chagas disease

77
Tx Chagas Disease

• Before CNS involvement occurs, suramin, a
  complex, non-metal-containing, organic compound,
  is tx of choice
• For American trypanosomiasis, tx is of limited
  efficacy
• Nifurtimox and benzimidazole clear the
  parasitemia and reduce severity of acute illness
• There is a high incidence of adverse effects
• Conservative tx is most appropriate for pt with
  CHF from Chagas myocarditis
• GI complications(megaesophagus megacolon) may
  be txed surgically

78
(No Transcript)
79
Chronic Chagas

• Occurs in 10-30 of infected persons yrs to
  decades later
• Heart (myocarditis, arrhythmias, thromboembolism,
  and cardiac failure) GI (megaesophagus and
  megacolon)
• In the remaining infected but asymptomatic phase
  pts may pass the disease through transfusion

80
African Trypanosomiasis

• In West Africa due to Trypanosoma brucei
  gambiense infection
• In East Africa caused by Trypanosoma brucei
  rhodesiense infection
• Vectors are usually several species of tsetse
  flies
• Cutaneous manifestations include a localized bite
  rxn (trypanosomal chancre) an annular
  eruption coinciding with fever spike

81
(No Transcript)
82
Rhodesian Trypanosomiasis

• Endemic among cattle-raising tribes of East
  Africa
• With savannah habitat of the vectors determining
  its geographic distribution
• Wild game and livestock are reservoir hosts as
  well as humans
• The tsetse fly Glossina morsitans is the
  principal vector

83
Gambian Trypanosomiasis

• Humans are the only vertebrate host and the
  palpalis group of tsetse flies is the
  invertebrate host
• These flies are found close to water
• Their fastidious biologic requirements restrict
  their distribution distribution of disease
• Incidence is seasonal, with humidity and
  temperature being determining factors
• Highest incidence is in males 20-40 yrs old in
  tropics of West and Central Africa

84

• Bite rxn earliest lesion
• Called trypanosomal chancre
• Resembles a boil but is painless
• Aspirated fluid contains actively dividing
  trypanosomes

85
(No Transcript)
86
CLASS SPOROZOA

• Toxoplamosis

87
Toxoplasmosis

• A zoonosis caused by a parasite protozoan
• Called Toxoplasma gondii
• Manifestations vary (mild-severe)infection may
  be congenital or acquired
• Congenital infection occurs from placental
  transmission-abortion or stillborn may result
• Congenital toxoplasmosis presents with triad of
  hydrocephalus, chorioretinitis, and cerebral
  calcification
• In addition there may be hepatosplenomegaly and
  jaundice
• Skin changes are rare and nonspecific

88
Congenital Toxoplasmosis

• Macular and hemorrrhagic eruptions predominate
• Blueberry muffin lesions, reflect
  dermatoerythropoesis may occur
• Abnormal hair growth and exfoliative dermatitis
  may also occur

89
Acquired Toxo

• Cutaneous and subcutaneous nodules, macular,
  papular, and hemorrhagic eruptions, followed by
  scarlatiniform desquamation, roseola-like,
  erythema multiforme-like, and lichen planus-like
  eruptions as well as exfoliative dermatitis
• Eruption is usually accompanied by high fever and
  general malaise

90
Acquried Toxo

• Diagnosis of acquired toxo is important to
• healthy pregnant women concerned about recent
  exposure
• adults with lymphadenopathy, fever, and myalgia,
  acute or chronic, who might have other serious
  diseases, such as lymphoma
• immunocompromised persons such pts with AIDS,
  in whom toxoplasmosis might be fatal
• it is the most common cause of focal encephalitis
  in pts with AIDS

91
Acquired Toxo

• 20 of pregnant women have already had the
  disease and are protected
• They are identified by a positive test very early
  in pregnancy, or just before pregnancy
• A high titer just before the twentieth week of
  gestation might be an indication for tx or such a
  test before delivery-tx of infant
• Immunofluorescence or complement fixation tests
  may be helpful

92
Toxoplasmosis

• Diagnosis in adults is made by rising or high
  antibody test
• Characteristic histologic changes in lymph nodes
  may be confirmatory
• In congenital cases and rarely in acquired ones,
  chorioretinitis may occur a decade or more after
  infection
• In congenital infection chorioretinitis is
  usually bilateral, whereas in acquired type it is
  usually unilateral

93
Toxoplasmosis

• Toxoplasma gondii is a crescent-shaped, oval, or
  round protozoan
• Can infect any mammalian or avian cell
• Disease often is acquired through contact with
  animals-cats usually
• Two major routes of transmission oral and
  congenital
• Meats used for human consumption may contain
  tissue cysts, therefore serving as a source of
  infection when eaten raw or undercooked
• No evidence of human to-human spread other than
  from mother to fetus

94
Toxodiagnosis

• Cannot be made clinically alone
• Must isolate the organism
• Protozoa can be found in tissue sections, smears,
  or body fluids by Wrights or Giemsa stain
  characteristic lymph node histology
  serologically
• Mouse inoculation with properly prepared tissue,
  ie lymph node, spinal fluid, or peripheral blood,
  may isolate and identify the parasite if stained
  with Giemsa or Wrights stain
• Antibodies are most commonly detected by
  Sabin-Feldman dye test, which becomes positive
  10-14 days after initial infection
• Maximum titer is attained in 4-5 weeks

95
Toxoplasmosis

• Worldwide distribution, with several areas having
  a greater than 90 seropositivity
• Occurs in eastern U.S. more frequently than in
  western U.S.
• Resevoirs of infection reported have been dogs,
  cats, cattle, sheep, pigs, rabbits, rats,
  pigeons, and chickens

96
Toxoplasmosistx

• Combination of pyrimethamine (Daraprim), and
  sulfadiazine act synergistically and form an
  effective tx
• Dosages and total tx time vary according to age
  and immunologic competence of infected pt
• Pyrimethamine is a folic acid antagonist, so
  concomitant folinic acid therapy is recommended

97
Phylum Cnidaria

• Jellyfish
• Hydroids
• Corals
• Sea anemones
• All are radial marine animals

98
Portugese Man-of-War Dermatitis

• Stings are characterized by linear lesions
• Erythematous, urticaria, and even hemorrhagic
• Common sites are forearms, sides of trunk,
  thighs, and feet

99
Portuguese Man-of-War Dermatitis

• Usual local manifestations are sharp, stinging,
  and intense pain
• Internally there may be severe dyspnea,
  prostration, nausea, abdominal cramps,
  lacrimation, and muscular pains
• Death may occur if areas stung are large in
  relation to size of pt
• Fluid of nematocytes contain toxin that is
  carried into human victim through barbs along the
  tenticle
• Venom is a neurotoxic poison that can produce
  marked cardiac changes

100
Portugese Man of-War Dermatits

• Each Portuguese man-of-war is a colony of
  symbiotic organisms consisting of a blue to red
  float or pneumatophore with a gas gland
• Several gastrozooids measuring 1-20 mm,
  reproductive polps, and fishing tentacles bearing
  the nematocytes from which barbs are ejected
• Hydroid is found mostly along southeastern
  Florida coastline and in Gulf of Mexico, and on
  windward coasts throughout the mid-Pacific and
  South Pacific

101
Jellyfish Dermatitis

• Produces similar lesions of man-of-war, except
  not as linear
• Delayed and persistent lesions were described by
  Reed et al from stings incurred in the Aegean and
  Caribbean areas
• Prolonged hypersensitivy reactions have been
  reported associated with specific antijellyfish
  immunoglobulins

102

• The most dangerous of all is Chironex fleckeri,
  the Australian sea wasp
• It is colorless and transparent
• Its sting is often fatal
• Another seas wasp Carybdea marsupialis, is much
  less dangerous and occurs in Caribbean

103
Seabathers eruption

• An acute dermatitis beginning a few hrs after
  bathing in the ocean
• Erythematous macules and papules appear that may
  develop into pustules or vesicles
• Urticarial plaques may be present less commonly
• Crops of new lesions may occur for up to 72 hrs
• Eruption persists for 10-14 days on average
• It is quite pruritic

104

• Seabathers eruption occurs along the coast of
  the Atlantic Ocean and affects covered areas of
  body
• Cnidatian larvae become entrapped under bathing
  suit and the nematocyst releases its toxin
  because of external pressure
• Buttocks and waist are primarily affected, with
  breast also involved in women
• It has been noted that seabathers who take off
  their suit and shower soon after leaving the
  water may limit the eruptions

105
Hydroid, Sea Anemone, and Coral Dermatits

• Pts contacting the small marine hydroid Halecium
  may develop a dermatitis
• These organisms grows like a centimeter-thick
  coat of moss on submerged portions of vessels or
  pilings
• Sea anemones produce reactions similar to those
  produced by jellyfish and hydroids
• Coral cuts are injuries caused by exoskeleton of
  corals, Milleporina
• Milleporina have a largely undeserved reputation
  for becoming inflamed and infected for delayed
  healing

106
Milleporina

• The combination of implantation of fragments of
  coral skeleton and infection (since cuts occur
  moat commonly on feet) probably accounts almost
  entirely for these symptoms
• Detoxification as soon as possible after injury
  is advisable for all of these types of stings or
  cuts

107
Tx of Stings Cuts

• All therapy is the same fire corals, hydroids,
  jellyfish, sea anemone
• Soak wound in 5 acetic acid (vinegar)
• Leading alternative is isopropyl alcohol (40-70)
• Meat tenderizer has been reported to be effective
  but not as reliable as vinegar
• Detoxicant should be applied continuously for at
  least 30 mins

108
Tx-continued

• Next, any large visible tentacles should be
  removed with forceps in a double-gloved hand
• Remaining nematocytes should be removed by
  applying a layer of shaving cream and shaving
  area gently
• Fresh water and abrasion will worsen the
  envenomation
• Topical anesthetics or steroids may be applied
  after decontamination
• Systemic rxns may occur either through large
  amounts of venom or a previously sensitizing
  exposure from which anaphylaxis may result
• Specific antivenin is available for the
  box-jellyfish

109
Sponges and Bristleworms

• Sponges have horny spicules of silicon dioxide
  and calcium carbonate
• Some sponges produce dermal irritants such as
  halitoxin and okadaic acid
• Others may be colonized by cnidaria
• Allergic or irritant rxns may result
• Bristleworms may also produce stinging
• All of these may be txd by first using adhesive
  tape to remove spicules, then applying vinegar
  soaks and then applying a topical steroid

110
Sea Urchin Injuries

• Puncture wounds inflicted by brittle, fragile
  spines of seas urchins, mainly genus Diadema or
  Echinothrix, are stained blue-black by the spines
  and may contain fragments of the spines
• These are rarely large enough to require removal
• Foreign-body or sarcoidlike granulomas may
  develop
• Injuries from spines of genus Tripneustes have
  been reported to cause fatal envenomation-but
  this genus is not found on U.S. coasts
• Envenomations may occur from stingrays,
  scorpionfish, stonefish, catfish, weaverfish

111
Treatment

• These wounds should be immersed in nonscalding
  water (45 degrees C) for 30-90 mins or until pain
  subsides
• Calcified fragments may be visible on x-ray
  evaluation, with fluoroscopy guiding extraction
  of spines, especially on hands and feet
• Debridement and possibly antibiotic therapy for
  deep puncture wounds of hands and feet is
  recommended
• There is a specific antivenin for stonefish stings

112
Seaweed Dermatitis

• Caused by marine alga
• Dermatitis occurs 3-8 hrs after individual
  emerges from ocean
• Distribution is in parts covered by a bathing
  suit scrotum, penis, perineum. And perianal area
• Caused by marine plant-Lyngbya majuscula Gomont
• Observed on in bathers off windward shore of
  Oahu, Hawaii
• Prophylaxis refraining from swimming in waters
  turbid with such algae
• Shower within 5 mins after swimming active tx
  same as acute burns

113
Dogger Bank Itch

• Eczematous dermatitis caused by sea chervil,
  Alcyondium hirsutum
• A seaweed-like animal colony
• These mosses or sea mats are found on the Dogger
  Bank, an immense shelflike elevation under the
  North Sea between Scotland and Denmark

114
Phylum Platyhelminthes

• Flatworms two classes
• Trematodes Cestodes
• Cestodes segmented, ribbon-shaped flatworms that
  inhabit intestinal tract as adults and involve
  subcutaneous tissue, heart, muscle, eye in larval
  form
• Encased in a sac eventually becoming calcified

115
CLASS TREMATODA

• Schistosome cercarial dermatitis
• Severely pruritic, widespread, papular dermatitis
• Caused by cercariae of schistosomes for which
  humans are not hosts (usually waterfoal and
  rodents like muskrats)
• Eggs in excreta of these animals are deposited in
  water then hatch into swimming miracidia
• Miracidia enter a snail, where further
  development occurs
• From snail, free-swimming cercariae emerge to
  invade human skin on accidental contact

116
Schistosome Cercarial Dermatitis

• These swimming, colorless, multi-cellular
  organisms are less than a millimeter long
• Exposure to cercariae occurs when swimming or
  more often wading in water containing them
• They attack by burrowing into skin, where they
  die
• Species that cause this eruption cannot enter the
  bloodstream or deeper tissue
• After coming out of water a transient
  erythematous eruption appears
• After a few hrs eruption subsides and pruritis
  too
• After quiescent period of 10-25 hrs symptoms
  recur, erythematous macules papules develop in
  exposed areas

117
(No Transcript)
118

• After several days the dermatitis heals
  spontaneously
• There are two types freshwater swimmers itch
  saltwater marine dermatitis or clam-diggers itch
• It is not communicable
• Can be prevented by thoroughly washing and drying
  with a towel after exposure

119
Visceral Schistosomiasis (Bilharziasis)

• Cutaneous manifestations begin with mild itch and
  a papular dermatitis of feet and other parts
  after swimming in polluted streams containing
  cercariae
• Types of schistosomes causing this can penetrate
  into bloodstream and eventually inhabit venous
  system draining the urinary bladder (Schistosoma
  haematobium) or intestines (S. mansoni or S.
  japonicum)
• After an asymptomatic incubation period, there
  may be a sudden illness with fever and chills,
  pneumonitis, and eosinophilia petechial
  hemorrhages may occur

120
Cutaneous Schistosomiasis

• Granulomas most frequently involve genitalia,
  perineum, and buttocks
• These bilharziomas usually caused by eggs of S.
  haematobium or S. mansoni
• Vegetating, soft, cauliflower-shaped masses occur
• Fistulous tracts and extensive hard masses occur
  these are riddled by sinuses exudating a
  seropurulent discharge with characteristic odor
• Phagedenic ulcerations and pseudoelephantiasis of
  scrotum, penis, or labia may occur

121

• Schistosomal granulomas of the scrotum

122
(No Transcript)
123
Cutaneous Schistosmiasis

• Infrequently, ectopic or extra-genital lesions
  may occur mainly on trunk
• This is a papular eruption tending to group in
  plaques and become darkly pigmented and scaly

124
Cutaneous Schistosomiasis
125
Katayama Fever

• Severe urticarial eruption
• Aka urticarial fever
• Frequently present along with a S. japonicum
  infection
• Occurs at beginning of oviposition,4-8 weeks
  after infection
• Occurs mainly in China, Japan, Philippines
• Fever, malaise, abdominal cramps, arthritis, and
  liver and spleen involvement are seen
• Felt to be a serum sickness-like rxn

126
Katayama Fever

• Prevention includes reducing infection sources,
  preventing contamination by human excreta of
  snail-bearing waters, control of snail hosts,
  avoiding exposure to cercaria-infested waters
• Prophylactic measures are still being sought
  after
• Tx praziquantel (Biltricide) 20 mg/kg orally for
  each of two treatments in 1 day TOC
• S. japonicum requires 3 doses in 1 day
• Schistosomicides exhibit toxicity for host as
  well as for parasite
• Risk of undesirable side effects may be enhanced
  by concomitant cardiac, renal, or hepatosplenic
  disease

127
(No Transcript)
128
Cysticerosis Cutis

• Natural intermediate host of pork tape worm is
  the pig
• But humans may act in this role
• Tapeworm known as Taenia solium
• Larval stage of T. solium is Cysticercus
  cellulosae
• Infection takes place after ingestion of food
  contaminated with eggs or by reverse peristalsis
  of eggs or proglottides from intestines to
  stomach
• Eggs hatch, freeing the oncospheres
• Onchospheres enter general circulation and form
  cysts in various parts of body striated muscle,
  brain, eye, heart, and lung

129
Cysticercosis Cutis

• In subcutaneous tissues lesions are usually
  painless nodules containing cysticerci
• These are more or less stationary, numerous and
  often calcified (therefore seen on x-ray)
• Pain and ulceration may occur
• Disease is most prevalent in countries where pigs
  feed on human feces
• Ddx gumma, lipoma, epithelioma
• Positive dx is via incision and examination of
  interior of calcified tumor, where parasite will
  be found

130
Cysticercosis Cutis

• Tx Praziquantel 10mg/kg of body wtTOC for
  intestinal tapeworms
• Five times this dose for 15 days is required if
  CNS is involved
• This regimen has no effect on calcified
  parasites-these need to be surgically removed

131
Sparganosis

• Caused by larva of tapeworm of species Spirometra
• Adult tapeworm lives in intestines of dogs and
  cats
• Rare tissue infection
• Occurs in two forms
• Application sparganosis-occurs when an ulcer or
  infected eye is poulticed with flesh of an
  infected intermediate host-larvae become encased
  in small nodules in the infected tissues
• Ingestion sparganosis occurs when humans ingest
  inadequately cooked meat, such as snake or frog,
  or when humans drink water contaminated with
  cyclops which are infected with plerocercoid
  larvae

132
Sparganosis

• 1-2 slightly pruritic or painful nodules may form
  in subcutaneous tissue or on the trunk and legs
• Humans are the accidental intermediate host of
  the Sparganum which is the alternative name for
  the plerocercoid larva
• Tx is surgical removal or ethanol injection of
  infected nodules

133
(No Transcript)
134
Echinococcosis

• Also known as hydatid disease
• In humans, infection is produced by ova reaching
  mouth by hands, in food, or from containers
  soiled by ova-contaminated feces from an infected
  dog
• Leading to Echinococcus granulosus infestation of
  liver and lungs
• Soft, fluctuating, semitranslucent, cystic tumors
  may occur in skin, sometimes in supraumbilical
  area as fistulas from underlying liver
  involvement
• These tumors become fibrotic or calcified after
  the death of the larva
• Eosinophilia or intractable urticaria and
  pruritus may be present

135
Echinococcosis

• Tx excision with care not to rupture the cyst
• Albendazole combined with percutaneous drainage
  may also be used

136
Leeches

• Marine, freshwater, or terrestrial types
• After attaching to skin, they secrete an
  anticoagulant, hirudin
• They then engorge themselves with blood
• Local symptoms at site of bite include
  ulceration, bullae, hemorrhage, pruritus,
  whealing, necrosis
• Allergic rxns including anaphylaxis may occur
• They may be removed by applying salt, alcohol, or
  vinegar, or by use of a match flame
• Bleeding may be stopped by direct pressure or by
  applying a styptic pencil to site
• Medicinally leeches may be used to salvage tissue
  flaps threatened by venous congestion

137
CLASS NEMATODA

• Enterobiasis
• Hookworm
• Creeping Eruption
• Gnathostomiasis
• Larva Currens
• Dracunculiasis
• Filariasis

138
Enterobiasis

• Pinworm, seatworm, oxyuriasis
• Main complaint is nocturnal pruritus ani
• Seen most frequently in children
• Vagina may become infested with gravid pinworms
• Restlessness, insomnia, enuresis, irritability
  may be seen

139
Enterobiasis
140
Enterobiasis

• Cause by roundworm Enterobius vermicularis
• May infest small intestines, cecum, and large
  intestine of humans
• Worms, especially gravid ones, migrate toward
  rectum and at night emerge to peri-anal and
  perineal areas to deposit thousands of ova
• Worm then dies outside the intestines
• These ova are carried back to mouth of host on
  the hands
• Larvae hatch in duodenum and migrate into the
  jejunem and ileum where they reach maturity
• Fertilization occurs in the cecum, thus
  completing the life cycle

141
(No Transcript)
142
Enterobiasis

• Humans are only known host of pinworm
• It is probably the widest distributed of all
  helminths
• Infection occurs from hand-to-mouth transmission,
  often from handling soiled clothes, bedsheets,
  etc
• Ova under the fingernails are a common source
• Ova may be airborne and collect in dust on
  furniture and floors
• Investigation may show that all members of the
  family of an affected person harbor the infection
• It is common in orphanages and mental
  institutions and among people living in communal
  groups

143
Enterobiasis

• Diagnosis is made by demonstration of ova in
  smears taken from anal region early in morning
  before defecation
• With pt in knee-chest position, a smear is
  obtained from anus with a small eye curette
• This is placed on a glass slide with a drop of
  saline solution
• It is also possible to use Scotch tape, looping
  the tape sticky-side out over a tongue depressor
  and then pressing it several times against
  perianal region
• Tape is then smoothed out on a glass slide
• A drop of a solution containing iodine in xylol
  may be placed on the slide before the tape to aid
  in detection of ova

144
Enterobiasis

• These tests should be repeated on 3 consecutive
  days to rule out infection
• Ova may be detected under the fingernails of
  infected persons
• It is also feasible to identify dead pinworms in
  the stool
• Tx Albendazole 400 mg or mebendazole 100 mg
  repeated in 2 weeks
• Personal hygiene and cleanliness at home ar
  important
• Cut fingernails short, and scrub frequently
• Sheets, underwear, towels, pajamas, and other
  clothing should be laundered throughly and
  separately

145
Hookworm Disease

• AKA ground itch, uncinariasis, ancylostomiasis,
  necatoriasis
• Earliest skin lesions are erythematous macules
  and papules, which become vesicles in a few hrs
• These are itchy and occur on soles, toe webs, and
  ankles
• Contents of vesicles become rapidly purulent
• These lesions are produced by invasion of the
  skin by Ancylostoma or Nector larvae and precede
  the generalized symptoms of disease by 2-3 months
• Cutaneous lesions last less than 2 weeks before
  larvae continue their human life cycle
• Eosinophilia may rise to 40 around 5th day of
  infection

146
Hookworm Disease

• Onset of constitutional symptoms is accompanied
  by progressive iron deficiency anemia and
  debility
• Urticaria often occurs
• Skin becomes dry and pale or yellowish
• Hookworm is a specific communicable disease
  caused by Ancylostoma duodenale or Necator
  americanus
• In soil they become infective larvae in 5-7 days
• Tiny larvae (which can scarcely be seen with a
  small pocket lens), when they come into
  accidental contact with bare feet, penetrate skin
  and reach capillaries

147
Hookworm Disease

• Larvae are carried in circulation to
  lungs-through capillary walls into bronchi-move
  up trachea to pharynx and being swallowed,
  eventually reach their habitat in the small
  intestine
• Here they bury their heads in mucosa and begin
  their sexual life

148
Hookworm Disease

• Prevalent in most tropical and subtropical
  countries and is often endemic in swampy and
  sandy localities in temperate zones
• In temperate zones larvae are killed off each
  winter and soil is re-contaminated from humans
  the following summer
• Nector americanus prevails in Western Hemisphere,
  Central and South Africa, South Asia, Australia,
  Pacific islands

149
Hookworm Disease

• Defecation habits of infected individuals in
  endemic areas is responsible for its widespread
  distribution
• Also cause is human feces for fertilization in
  may parts of the world
• The climate is such that people go barefoot due
  to heat
• Finding the eggs establishes a diagnosis
• Ova appear in feces 5 weeks after onset of
  infection

150
Hookworm
151
Hookworm Disease

• Tx expulsion of parasites from body and tx by
  preventing re-infection through proper disposal
  of human feces
• Albendazole 100mg once or mebendazole 100 mg BID
  for 3 days is effective
• Prophylaxis depends on preventing fecal
  contamination of soil

152
Creeping Eruption

• AKA larva migrans
• Twisting, winding linear skin lesions produced by
  burrowing of larvae
• Victims are people who go barefoot at beaches,
  children playing in sandboxes, carpenters and
  plumbers working under homes, and gardeners
• Most common areas involved are feet, buttocks,
  genitals, and hands
• Onset characterized by local itching and
  appearance of papules at sites of infection

153
Larva Migrans

• Intermittent stinging pain occurs, and thin, red,
  tortuous lines are formed in skin
• Migrations begin 4 days after inoculation and
  progress at a rate of 2 cm per day
• Larvae may remain quiescent for several days or
  even months
• Linear lesions are often interrupted by papules
  marking sites of resting larvae

154
(No Transcript)
155
(No Transcript)
156
Larva Migrans

• As eruption advances, old parts tend to fade, but
  sometimes there are purulent manifestations
  caused by secondary infection erosions and
  excoriations caused by scratching may occur
• If disease is not interrupted by tx larvae
  usually die in 2-8 weeks, with resolution of
  eruption
• Rarely eruption has persisted for up to 1 yr

157
(No Transcript)
158
Larva Migrans

• Majority of cases in this country are caused by
  penetration by larvae of a cat and dog hookworm
  Ancylostoma braziliense
• This is acquired from body contact with excreta
  of dogs and cats
• This is common along coast of southwestern US
• Tx Ivermectin 150 micrograms/kg as a single
  12-mg dose or albendazole 200 mg BID for 3 days
• Criteria for successful tx are relief of symptoms
  and cessation of tract extension- usually occurs
  within a week
• Topical thiabendazole 10 oral suspension QID
  will help with pruritus and tracts become
  inactive within 1 week

159
Gnathostomiasis

• Characterized by migratory, intermittent,
  erythematous, urticarial plaques
• Each episode of painless swelling lasts from 7-10
  days and recurs every 2-6 weeks
• Movement of underlying parasite may be as much as
  1 cm/hr
• Total duration of illness may be 10 yrs
• Histopathologic exam of skin swelling will
  demonstrate eosinophilic panniculitis
• Clinical manifestation has been called larva
  migrans profundus
• Nematode Gnathostoma dolorosi or spingerum is
  cause

160
Gnathostomiasis

• Most cases occur in Asia or South America
• Eating raw flesh from second intermediate host,
  most commonly freshwater fish, in form of sashimi
  ceviche allows humans to become definitive host
• One report of eating raw snake flesh

• As the larval cyst in the flesh is digested,
  larva becomes motile and penetrates gastric
  mucosa, usually within 24-48 hrs of ingestion
• Symptoms then occur as migration of parasite
  continues
• Surgical removal is TOC if parasite can be
  located
• This can be combined with albendazole 400 mg
  daily or BID for 21 days

161
Larva Currens

• Intestinal infections with Strongloides
  stercoralis may be associated with a perianal
  larva migrans syndrome, called larva currens
• Named because of the rapidity of larval migration
  currens means running or racing
• An auto-infection caused by penetration of
  perianal skin by infectious larvae as they are
  excreted in feces
• An urticarial band is primary lesion of cutaneous
  strongyloidiasis

162
(No Transcript)
163
Larva Currens

• Often is a chronic disease
• Has been reported to last 40 yrs or more
• Symptoms include abdominal pain, diarrhea,
  peripheral eosinophilia
• Skin lesions originate within 30 cm of anus
• Extend as much as 10cm/day
• Fatal cases of hyper-infection occur in
  immunocompromised pts
• Parasite load increases dramatically and can
  produce fulminant illness
• Widespread petechiae and purpura and chronic
  urticaria may be a presenting sign of
  dissemination

164
Larva Currens

• Tx ivermectin 200 micrograms/kg/day for 2 days
  or albendazole 400 mg/day for 3 daysTOC
• Immunosuppressed hosts may be tx with
  thiabendazole 25 mg/kg BID for 7-10 days

165
Dracunculiasis

• Guinea worm disease or medina worm
• Endemic in India, southwest Asia, northeast South
  America, West Indies, and Africa
• Caused by Dracunculus medinensis contracted
  through drinking water contaminated with infected
  water fleas in which Dracunculus is parasitic
• In stomach, larvae penetrate into mesentery where
  they sexually mature in 10 weeks
• Female worm burrows to cutaneous surface to
  deposit her larvae and causes skin manifestations
• As worm approaches surface it may be felt as a
  cordlike thickening and forms an indurated
  cutaneous papule

166
(No Transcript)
167
(No Transcript)
168
Dracunculiasis

• Papule may vesiculate and a painful ulcer
  develops, usually on the leg
• Worm is often visible
• When parasite comes into contact with water, the
  worm rapidly discharges its larvae, which are
  ingested by water fleas (Cyclops), contaminating
  the water

169
Dracunculiasis

• Cutaneous lesion is usually on lower leg, but may
  occur on genitalia, buttocks, or arms
• There may also be urticaria, gastrointestinal
  upsets, eosinophilia, and fever
• Disease may be prevented by boiling water before
  drinking, providing safe drinking water through
  boreholes, or filtering water through mesh fibers
• Native tx consists of gradually extracting the
  worm a little each day, with care not to rupture
  it
• If ruptures larvae escape into tissues and
  produce fulminating inflammation
• Surgical removal is TOC
• Metronidazole 500 mg/day resolves inflammation
  and permits easier removal of worm so does warm
  water immersion

170
Filariasis

• Elephantiasis Tropica (elephantiasis Arabum)
• Widespread tropical disorder caused by
  infestation by filarial worms of Wuchereria
  bancrofti, Brugia malayi, or B. timori
• Characterized by lymphedema
• Resulting in hypertrophy of skin subcutaneous
  parts
• Enlargement of affected areas usually legs,
  scrotum, labia majora
• More common in men than women

171
Filariasis

• Onset characterized by recurrent attacks of acute
  lymphangitis
• Episodes last days weeks
• Occurs for months-yrs
• After each attack swelling subsides only
  partially
• As recrudescences supervene thickening and
  hypertrophy worsen
• Overlying epidermis becomes stretched, thin,
  shiny
• Over yrs becomes leathery, insensitive, verrucous
  or papillomatous from secondary pyogenic
  infection

172
Filariasis

• Involvement may then involve scalp, vulva, penis,
  female breasts, arms
• Legs are usually affected symmetrical manner
• Thickening becomes massive and pachydermatous
• Thickened integument hangs in apposing folds
  between which there is a fetid exudate

173
(No Transcript)
174

• Scrotal involvement causes area to become
  enormous and penis becomes hidden in it
• Skin, first glazed, later becomes coarse and
  verrucous or ulcerated or gangrenous
• Resistant urticaria may occur
• Filarial orchitis and hydrocele are common
• Testicle may enlarge rapidly to apple size and
  can be painful
• Swelling may subside within a few days,
  enlargement may be permanent
• Resulting obstruction and dilation of thoracic
  duct may occur obstruction of lower abdominal
  tributaries into urinary tract, chyle appears in
  urine

175
(No Transcript)
176
Filariasis

• Lobulated swellings of inguinal and axillary
  glands, called varicose glands occur
• These are caused by obstructive varix and
  dilation of lymphatic vessels
• Filaria are transmitted person-to-person by bites
  of mosquitoes
• Culex, Aedes, and Anopheles species
• Adult worms are threadlike, cylindrical and
  creamy white
• Females are 4-10 cm long
• Microfilarial embryos may be seen coiled each in
  it