Parasitic Infections: Clinical Manifestations, Diagnosis and Treatment

1
Parasitic InfectionsClinical Manifestations,
Diagnosis and Treatment

• Lennox K. Archibald, MD, PhD, FRCP, DTMH
• Hospital Epidemiologist
• University of Florida

2
The Reality

• 1.3 billion persons infected with Ascaris (1 4
  persons on earth)
• 300 million with schistosomiasis
• 100 million new malaria cases/yr
• At UCLA, 38 of pediatric and dental clinic
  children harbored intestinal parasites

3
Case1

• 42-yr-old previously healthy, UF professor
• 6-week history of intermittent diarrhea, flatus
  and abdominal cramps
• Diarrhea x8/day pale no blood or mucus
• No tenesmus
• Illness began slowly during camping trip to
  Colorado with loose stools
• Spontaneously remission for 5-6 days at a time,
  then recur

4
Case 1

• His 8-yr-old son had had a mild course of watery
  diarrheaascribed to viral gastroenteritis by
  general practitioner
• Stool smearno pus cells
• However, wet preps showed

5
(No Transcript)
6
(No Transcript)
7
Diagnosis?
8
Giardiasis (G. lamblia)

• Should be suspected in prolonged diarrhea
• Contaminated water often implicatedoutbreaks
• Campers who fail to sterilize mountain stream
  water
• Person-person in day care centers
• MSM
• Symptoms usually resolve spontaneously in 4-6
  weeks

9
Giardiasis Tests of choice

• Examination of concentrated stools for cysts (90
  yield after 3 samples)
• Usually no PMNs
• Stool ELISA, IF Antigen (up to 98
  sensitive/90-100 specific)
• Consider aspiration of duodenal
  contents--trophozoites
• Treatment Metronidazole for 5-7 days

10
Case 2

• 40 y/o male vicar returned from 2 years of
  missionary work in South Africa
• Excellent health throughout stay there
• 3 months after returning to U.S.
• Suddenly ill with abdominal distension
• Fever
• Periumbilical pain
• Vomiting
• Blood-tinged diarrheal stools
• Denied arthritis /known exposure to parasites
• Family history of inflammatory bowel disease

11
Case 2

• Physical examination
• Acutely ill
• Distended abdomen
• No hepatomegaly or splenomegaly
• Decreased bowel sounds
• Stool exam
• Gross blood present
• No pus cells
• Negative for OP, one negative CS

12
Sigmoidoscopy revealed

• Multiple punctate bleeding sites at 7 to 15 cm
  with normal appearing mucosa between sites
• This mucosa easily denuded when pressure applied
  to it, leaving large areas of bleeding submucosa

13
Case 2

• Diagnosed with ulcerative colitis
• Started on corticosteroids
• Temperature rose to 40C
• Abdomen distension increased and worsening of
  symptoms
• Emergency laparotomy for toxic megacolon

14
(No Transcript)
15
(No Transcript)
16
Diagnosis?
17
Entamoeba histolytica

• One of 7 amoebae commonly found in humans
• Only one that causes significant disease
• Causes intestinal (diarrhea and dysentery) and
  extraintestinal (liver primarily) disease
• In US
• Institutionalized patients
• MSM
• Tourists returning from developing countries
• Patients with depressed cell mediated immunity

18
Trophozoites with ingested RBC
19
Trophozoites in colon tissue (H E stain)
20
Cyst (wet mount)
21
Amoebiasis Clinical Manifestations

• Symptoms depend on degree of bowel invasion
• Superficial watery diarrhea and nonspecific GI
  complaints
• Invasive gradual onset (1-3 weeks) of abdominal
  pain, bloody diarrhea, tenesmus
• Fever is seen in minority of patients

22
Amoebiasis Clinical Manifestations

• Can be mistaken for ulcerative colitis
• Steroids can dramatically worsen and precipitate
  toxic megacolon
• Amebic liver abscesses
• RUQ pain, pain referred to right shoulder
• High fever
• Hepatomegaly (50)

23
Amoebic abscessremember

• Can occur in lung, brain, spleen

24
Amoebic Abscess

• Liquefaction of liver cells
• Do not contain pus
• Anchovy paste sauce
• Culture of contents usually sterile
• Liver affected
• 53-right lobe
• 8-left lobe

25
(No Transcript)
26
(No Transcript)
27
Remember

• That stool is merely a convenient vehicle passing
  by
• Amoebae live the bowel wall
• Direct observation preferable to mere examination
  of stool
• Trophozoites best seen in direct scrapings of
  ulcers

28
Amoebiasis Treatment

• Most respond to metronidazole
• Open surgical drainage should be avoided, if at
  all possible

29
Case 3

• Previously healthy 3-year-old girl
• Attends day-care center
• 7 day history of watery diarrhea
• Nausea
• Vomiting
• Abdominal cramps
• Low-grade fever

30
(No Transcript)
31
Case 4

• 34 year-old AIDS patient
• Debilitating, cholera-like diarrhea
• Severe abdominal cramps
• Malaise
• Low-grade fever
• Weight loss
• Anorexia

32
(No Transcript)
33
Diagnosis?Case 3 4
34
Three cysts stained pale red are seen in the
center with this acid fast stain
35
Modified acid-fast stain of stool showing red
oocysts of Cryptosporidium parvum against the
blue background of coliforms and debris
36
Cryptosporidium parvum

• Causes secretory diarrhea 10 liter/day
• Significant cause of death in HIV/AIDS
• Animal reservoirs
• Incubation period 5-10 days

37
Cryptosporidium parvum

• Infants young children in day-care
• Unfiltered or untreated drinking water
• Farming practices lambing, calving, and
  muck-spreading
• Sexual practices oral contact with stool of an
  infected individual
• Nosocomial setting with other infected patients
  or health-care employees
• Veterinarians contact with farm animals
• Travelers to areas with untreated water
• Living in densely populated urban areas
• Owners of infected household pets (rare)

38
Diagnosis and Treatment

• Best diagnosed by stool exam
• No known effective treatment
• Nitazoxamide shortens duration of diarrhea

39
Case 5

• Mr. Mrs. R. were sailing with their 3 children
  in Jamaica
• Living primarily on the boat with several day
  trips to a small coastal island
• On island, ate several types of tropical fruit
• Both became suddenly ill with fevers, chills,
  muscle aches, and loss of appetite.
• Sought treatment locally, and were diagnosed with
  hepatitis, likely due to ingestion of toxic fruit

40
Case 5

• Two days later, Mr. R. became jaundiced and
  passed dark urine
• He progressively worsened, became comatose and
  died
• In the meantime, Mrs. R. was transferred to SUF
  for liver transplant

41
Case 5

• None of the children were sick despite having
  eaten the same fruits and other foods.
• The family had taken chloroquine prophylaxis
  against malaria, but the parents stopped the
  medicine 2 weeks prior to becoming ill because of
  side effects.

42
(No Transcript)
43
(No Transcript)
44
Falciparum vs. Vivax

• Location Falciparum confined to tropics and
  subtropics vivax more temperate
• Falciparum infects RBC of any age others like
  reticulocytes
• Falciparum-infected RBCs stick to vascular
  endothelium causing capillary blockage

45
(No Transcript)
46
(No Transcript)
47
Malaria Genetic susceptibility

• Two genetic traits associated with decreased
  susceptibility to malaria
• Absence of Duffy blood group antigen blocks
  invasion of Plasmodium vivax
• Significant number of Africans
• Persons with sickle cell hemoglobin are resistant
  to P. falciparum
• Sickle cell disease and trait

48
Malaria Clinical manifestations

• Non-specific, flu-like illness
• Incubation
• P. falciparum 9-40 days
• Non-P. falciparum may be prolonged
• P. vivax 6-12 months
• P. malariae and ovale years
• Fever is the hallmark of malaria
• Classically, 2-3 day intervals in P. vivax and
  malariae
• More irregular pattern in P. falciparum
• Fever occurs after the lysis of RBCs and release
  of merozoites

49
Malaria Clinical manifestations

• Febrile paroxysms have 3 classic stages
• Cold stage
• Pt feels cold and has shaking chills
• 15-60 mins. prior to fever
• Hot stage
• 39-41C
• Lassitude, loss of appetite, bone and joint aches
• Tachycardia, hypotension, cough, HA, back pain,
  N/V, diarrhea, abdo pain, altered consciousness
• Sweating stage
• Marked diaphoresis followed by resolution of
  fever, profound fatigue, and sleepiness
• 2-6 hours after onset of hot stage

50
Malaria Clinical manifestations

• Other symptoms depend on malaria strain
• P. vivax, ovale and malariae few other sxs
• P. falciparum
• Dependent upon host immune status
• No prior immunity/splenectomy ? high levels of
  parasitemia ? profound hemolysis
• Vascular obstruction and hypoxia
• Kidneys renal failure
• Brain (CNS) ? hypoxia, coma, seizures
• Lungs pulmonary edema
• Jaundice hemoglobinuria (blackwater fever)

51
Malaria Clinical manifestations

• Always suspect malaria in travelers from
  developing countries who present with
• Influenza-like illness
• Jaundice
• Confusion or obtundation

52
Diagnosis

• Giemsa-stained blood smear
• Thick and thin smears
• P. falciparum
• Best just after fever peak
• Others
• Smears can be performed at any time
• Examine blood on 3-4 successive days

53
Differences in strains

• P. falciparum
• No dormant phase in liver
• Multiple signet ring trophs per cell
• High percentage (gt5) parasitized RBCs considered
  severe

54
Differences in strains

• P. vivax and ovale
• Dormant liver phase
• Single signet ring trophs per cell
• Schuffners dots in cytoplasm
• Low percent (lt 5) of parasitized RBCs

55
Differences in strains

• P. malariae
• No dormant stage
• Single signet ring trophs per cell
• Very low parasitemia

56
Treatment

• P. falciparum malaria can be fatal if not
  promptly diagnosed and treated
• Non- P. falciparum malaria rarely requires
  hospitalization
• Widespread drug resistance dictates regimen
  (www.cdc.gov/travel CDC malaria hot line
  770-488-7788).

57
TreatmentUncomplicated malaria

• P. vivax, ovale, malariae, chloroquine-susceptible
  falciparum
• Chloroquine
• Primaquine for dormant liver forms
• Chloroquine-resistant falciparum
• Quinine plus doxycycline
• Mefloquine
• Atovaquone plus proguanil (AP)
• Artemisins (common in SE Asia due to multi-drug
  resistance)

58
TreatmentSevere malaria

• Drug options
• Quinidine gluconateonly approved parenteral
  agent in US
• Artemisin

59
Prevention

• Mefloquine
• Doxycycline
• Nets
• 30-35 DEET
• Permethrin spray for clothing and nets

60
And dont forget baggage malaria!
61
Case 5

• Mrs. R. was treated with IV quinidine and
  improved rapidly.
• In retrospect, Mr. R. had died from untreated
  blackwater fever
• Few parasites in peripheral blood
• Acute renal failure

62
Case 6

• A 24-year-old white male army officer
• Referred to the VA ID clinic with a 3-month
  history of a lesion on his right leg, developing
  approximately 2 weeks after returning from Iraq
• Recent travel history 1 month in Kuwait and 2
  months traveling between Kuwait and Iraq
• Recalled being bitten numerous times by small
  flying insects and other nasty bugs

63
Case 6

• Physical examination essentially normal except
  for
• Non-tender (20 15 mm) scaly erythematous plaque
  with a moist central erosion of the left
  popliteal area.
• There was no lymphadenopathy and no mucosal
  lesions were noted

64
(No Transcript)
65
Diagnosis?
66
(No Transcript)
67
An intact macrophage practically filled with
amastigotes (arrows),
68
Leishmaniasis

• Tropical areas where phlebotomine sandfly is
  common South America, India, Bangladesh, Middle
  East, East Africa
• Sandfly introduces flagellated promastigote into
  human ? ingested by macrophages ? develops into
  nonflagellated amastigote

69
Leishmaniasis

• Cutaneous
• Most common among farmers, settlers, troops and
  tourists in Mid East (L. major and tropica),
  Central and South America (L. mexicana,
  braziliensis, amazonensis, and panamensis)
• L. mexicana reported in Texas
• Visceral (kala azar)
• Anemia, leukopenia, thrombocytopenia,
  hypergammaglobulinemia common

70
Leishmaniasis Diagnosis

• Biopsy and Giemsa stain with amastigotes
• Species most prevalent in different places
• L. donovani India
• L. infantum Mid East
• L. chagasi Latin America
• L. amazonensis -- Brazil

71
Visceral Leishmaniasis

• Dissemination of amastigotes throughout the
  reticulendothelial system of the body
• Spleen
• Bone marrow
• Lymph nodes
• Opportunistic infection in AIDS patients
• Ineffective humeral response

72
Hepatosplenomegaly
73
Splenic aspirate

• Most satisfactory method
• Spleen must be at least 3cm below LCM
• Aspirate stained with Giemsa

74
Leishmaniasis treatment

• Only drug approved in US is Amphotericin B
• Treatment of cutaneous disease depends on
  anatomic location
• Many spontaneously heal and do not require
  treatment

75
(No Transcript)
76
Remember..

• The factors determining the form of
  leishmaniasis
• Leishmanial species
• Geographic location
• Immune response of the host

77
Case 7

• 38-year-old businessman
• Previously fit
• 2-week history of fever since returning from
  Brazil business trip
• Flu-like symptoms and myalgia
• Had consumed steak tartare in Brazil
• Results all unremarkable---normal WBC and ESR
  negative smears CXR and urine OK
• Continued to have fever, tachycardia and myalgia

78
Case 8

• A 29-yr-old man with AIDS (CD4 count59) presents
  with a 2 week history of headache, fevers and new
  onset seizures
• He had not been taking any antiretroviral
  medications

79
Cases 7 8

• What parasite could
• cause this picture?

80
AIDS Patient
81
AIDS Patient
82
Toxoplasma gondii cyst in brain tissue with H E
stain (100x)
83
For the businessman

• Toxoplasma serology was positive at a very high
  titer
• Responded to treatment with sulphonamide
  pyrimethamine
• No relapse

84
Transmission

• Eating oocysts excreted by cats harboring sexual
  stages of parasite
• Outbreaks traced to inadequately cooked meat of
  herbivores (raw beef)
• Mutton

85
Toxoplasma gondii

• Worldwide distribution
• Human infection
• Ingestion of cysts in undercooked meat of
  herbivores
• Water/food contaminated with oocysts
• Congenitally
• Infected organs, blood (less common)
• Prevalence of latent infection in US about 10
  France about 75
• Generally higher in less-developed world
• 50 in AIDS patients up to 90 of AIDS patients
  in developing world

86
Toxoplasma gondii Immunocompetent hosts

• Latent infection (persistence of cysts) is
  generally asymptomatic
• Cervical lymphadenopathy (10-20)
• Mono-like presentation (lt1 of all mono-like
  illnesses)
• Chorioretinitis
• Very rare myocarditis, myositis

87
Toxoplasma gondii Immunocompromised hosts

• Often life-threatening
• Almost always reactivation of latent infection
• AIDS
• Encephalitis most common manifestation
• Usually subacute onset/focal (if CD4lt 200)
• Mental status changes, seizures, weakness,
  cranial nerve abnormalities, cerebellar signs,
• Can present as acute hemiparesis/language deficit
• Usually multiple ring-enhancing lesions on CT/MRI
• Pneumonitis
• Chorioretinitis

88
Toxoplasma gondii Clinical manifestations

• Immunocompromised hosts
• Non-AIDS (transplants, hematologic malignancies)
• CNS 75
• Myocardial 40
• Pulmonary 25

89
Toxoplasma gondii Clinical manifestations

• Congenital
• Acute infection asymptomatic in mother
• Clinical manifestations range no sequelae to
  sequelae that develop at various times after
  birth
• Chorioretinitis
• Strabismus
• Blindness
• Epilepsy, mental retardation, pneumonitis,
  microcephaly, hydrocephalus, spontaneous
  abortion, stillbirth

90
Toxoplasma gondii diagnosis

• Clinical suspicion crucial
• Serology is primary method of diagnosis
• IgM, IgG
• Histopathology
• Tachyzoites in tissue sections or body fluid
  (difficult to stain)
• Multiple cysts near necrotic, inflammatory
  lesions

91
Toxoplasma gondii Treatment

• Immunocompetent adults are usually not treated
  unless visceral disease is overt or symptoms are
  severe and persistent
• Immunodeficient patients
• Latent disease not treated
• Active disease pyrimethamine sulfadiazone
  folinic acid

92
Toxoplasma gondii Treatment

• Congenital
• Treatment of acute infected pregnant women
  decreases but does not eliminate transmission
• Spiramycin
• If fetal infection is documented, treat with
  pyrimethamine sulfadiazone folinic acid
• Postnatal treatment pyrimethamine sulfadiazone
  folinic acid

93
Case 22

• 25-year-old Caucasian woman presented with 1-week
  history of fever, chills, sweating, myalgias,
  fatigue
• No travel abroad
• Had gone cranberry picking in Massachusetts
  approx 3 weeks earlier
• PE anemic, hepatosplenomegaly
• Blood workup hemolytic anemia, reduced
  platelets 

94
Thick smear
95
Thin smear
Maltese cross
96
Diagnosis??
97
Babesiosis

• Babesiosis caused by hemoprotozoan parasites of
  the genus Babesia
• gt100 species reported
• Few actually cause human infection

98
Babesiosis

• Babesia microti
• Life cycle involves two hosts
• Deer tick, Ixodes dammini, (definitive host)
  introduces sporozoites into white-footed mouse
• Once ingested by an appropriate tick gametes
  unite and undergo a sporogonic cycle resulting in
  sporozoites
• Humans enter cycle when bitten by infected ticks

99
Babesiosis

• Deer are the hosts upon which the adult ticks
  feed and are indirectly part of the Babesia cycle
  as they influence the tick population

100
Babesiosis

• Clindamycin plus quinine
• Atovaquone plus azithromycin
• Exchange transfusion in severely ill patients
  with high parasitemia
• Approved by FDA

101
Case 9

• 6-year-old son of seasonal farm worker
• Presents with cough and fever, wheeze
• CXR reveals a lobar pneumonia
• Admitted for initial therapy
• After 2 days of antibiotics, with good
  defervescence, a worm is found in his bed
• Stool exam reveals

102
(No Transcript)
103
Diagnosis?
104
Ascaris lumbricoides

• In GI tract, few symptoms in light infections
• Nausea
• Vomiting
• Obstruction of small bowel or common bile duct.
• Pulmonary symptoms due to migration
• Alveoli (verminous pneumonia)cough, fever
  wheeze, dyspnea, X-ray changes, eosinophilia

105
Effects of Adult Ascaris Worms

• Depends on worm load
• Effects
• Mechanical obstruction, volvulus,
  intussusception, appendicitis, obstructive
  jaundice, liver abscesses, pancreatitis, asphyxia
• Toxic and Metabolic
• Malnutrition (complex)

106
Ascaris lumbricoidesDiagnosis

• Characteristic eggs on direct smear examination
• If treating mixed infections, treat Ascaris first
• Mebendazole
• Pyrantel
• Control
• Periodic mass treatment of children, health
  education, environmental sanitation

107
(No Transcript)
108
Case 10

• 11-year-old female
• Doing poorly in school
• Not sleeping well
• Anorectic
• Complains of itching in rectal region throughout
  the day
• A Scotch-tape test reveals

109
(No Transcript)
110
(No Transcript)
111
(No Transcript)
112
Diagnosis?
113
Enterobius (Pinworm)

• 18 million infections in U.S.
• Incidence higher in whites
• Preschool and elementary school most often
• Mostly asymptomatic
• Nocturnal anal pruritis cardinal feature due to
  migration and eggs
• May have insomnia, possible emotional symptoms
• DS-eggs or adults on perineum scotch tape
• Mebendazole 100 mg. Repeat in 2 weeks. Pyrantel
  pamoate 11 mg/kg repeat 2 weeks

114
Case 11

• 69-year-old male was admitted to VA Hospital
• Far East Prisoner of War (FEPOW)
• COPD--steroids for 3 years
• 2-month history of nausea, vomiting and anorexia
• 25 pounds weight loss

115
On the day of admission

• Fever, confusion, and not able to get out of
  bed---transported to the hospital
• Initial blood work
• Elevated WBC
• Raised eosinophil count 4 times normal
• Underwent UGI endoscopy
• Duodenal biopsy obtained

116
(No Transcript)
117
Diagnosis
118
Strongyloides Crucial Aspects of Life Cycle

• Infection acquired through penetration of intact
  skin
• Infection may persist for many years via
  autoinfection
• In immunocompromised patients, there is risk of
  dissemination or hyperinfection
• Hyperinfection syndrome

119
Disseminated Strongyloidiasis

• High mortality?75
• Penetration of gut wall by infective larvae
• Gut organisms carried on the surface of larvae
  results in polymicrobial sepsis, meningitis
• Larvae disseminate into all parts of body CNS,
  lungs, bladder, peritoneum

120
SummaryClinical Findings

• Defective cell-meditated immunity steroids,
  burns, lymphomas, AIDS (?)
• Gl symptoms in about two-thirds
• Abdominal pain
• Bloating
• Diarrhea
• Constipation
• Wheezing, SOB, hemoptysis

121
SummaryClinical Findings

• Skin rash or pruritis in one-third
• Larva currens (racing larva)
• Intensely pruritic
• Linear or serpiginous urticaria with flare that
  moves 5-15 cm/hr
• Usually buttocks, groin, and trunk
• In dissemination, diffuse petechiae and purpura

122
Summary-Clinical Findings

• Eosinophilia 60-95
• Less if on steroids

123
Case 12

• 57 year old farmer from Dixie County
• Presents with profound SOB
• Physical examination anemic otherwise
  unremarkable
• Laboratory examination reveals a profound anemia
  (hct 24) with aniso and poikilocytosis
• Remainder of laboratory examination normal.

124
(No Transcript)
125
Diagnosis?
126
(No Transcript)
127
Hookworm

• Hookworm responsible for development of USPHS
• Caused by two different species (North American
  and Old World)
• Very similar to strongyloides in life cycle
• Attaches to duodenum, feeds on blood
• Elaborates anticoagulant, attaches and reattaches
  many times
• Loss of around 0.1 ml/d of blood per worm

128
(No Transcript)
129
(No Transcript)
130
Case 13

• 8-yr-old schoolgirl visiting the U.S. from
  Malaysia
• 1 week history of epigastric pain, flatulence,
  anorexia, bloody diarrhea
• No eosinophilia noted
• Clinical diagnosis of amoebic dysentery made
• However, microscopy of stool prep

131
(No Transcript)
132
Diagnosis?
133
Trichuris trichiura (Whipworm)

• Common in Southeast U.S.
• Frequently coexists with ascaris
• Entirely intraluminal life cycleeggs are
  ingested
• Frequently asymptomatic
• Severe infections diarrhea, abdominal pain and
  tenesmus
• Rectal prolapse in children
• DS-eggs in stool
• Mebendazole 100 mg bid x 3 days

134
(No Transcript)
135
(No Transcript)
136
(No Transcript)
137
Case 14

• 18-year-old trailer park handyman seen in ER
• Worked under trailers wearing shorts and no shirt
• Developed intensely pruritic skin rash
• Unable to sleep
• WBC 18,000
• 65 eosinophils.

138
(No Transcript)
139
Case 15

• An 8 year old boy
• Presents with skin lesions and itching after
  spending the summer at a beach condo in St.
  Augustine with his family (mother, father,
  younger sister, dog and cat).
• Legs show several raised, reddened, serpiginous
  lesions that are intensely pruritic.

140
(No Transcript)
141
Diagnosis ?
142
Cutaneous Larva Migrans

• Caused by filariform larvae of dog or cat
  hookworm (Ancylostoma braziliense or Ancylostoma
  duodenale
• Common in Southeast U.S.
• Red papule at entry with serpiginous tunnel
• Intense pruritis
• Self limiting condition
• Diagnosis clinical
• Topical or oral thiabendazole 25 mg/kg bid for
  3-5 days
• May use ethyl chloride topically

143
Cutaneous larva migrans (creeping eruption)

• More common in children
• Larvae penetrate skin and cause tingling followed
  by intense itching.
• Eggs shed from dog and cat bowels develop into
  infectious larvae outside the body in places
  protected from desiccation and extremes of
  temperature
• Shady, sandy areas under houses, at beach, etc.

144
Cutaneous larva migrans (creeping eruption)

• Usually not associated with systemic symptoms

145
Cutaneous larva migrans (creeping eruption)

• Diagnosis and treatment
• Skin lesions are readily recognized
• Usually diagnosed clinically
• Generally do not require biopsy
• Reveal eosinophilia inflammatory infiltrate
• Migrating parasite is generally not seen
• Stool smear will reveal eggs

146
(No Transcript)
147
(No Transcript)
148
Visceral Larva Migrans

• Infection with dog or cat round worms
• Toxocara canis Toxocara catis
• Underdiagnosed based on seroprevalence surveys
• Heavy infections associated with fever, cough,
  nausea, vomiting, hepatomegaly, and eosinophilia
• Uncommon in adults
• Ocular type more common in adults
• Diagnosis-ELISA
• Thiabendazole 25 mg/kg bid X 5 days

149
Case 17

• A 34 yr-old woman from Saudi Arabia
• Radiation and cyclophosphamide, adriamycin,
  vincristine and prednisone for diffuse large B
  cell lymphoma of the neck.
• Mild eosinophilia (AEC500) at the time of
  diagnosis
• 4 months after initiation of chemo, c/o
  intermittent diffuse abdominal pain, bloating,
  constipation and occasional rectal bleeding.
• Absolute eosinophil count 1000

150
Case 17

• No evidence of lymphoma found on re-staging
• Completed chemo, was deemed to be in complete
  remission, but had persistence of GI complaints.
• Upper endoscopy was unrevealing.
• Colonoscopy and biopsy revealed granulomatous
  inflammation, prominent eosinophilic infiltrate,
  surrounding a collection of eggs.

151
(No Transcript)
152
Chronic intestinal schistosomiasis
153
Case 17

• The patient was treated with praziquantel and did
  not have relapse of symptoms at 2-year follow-up
• AEC250

154
Schistosomiasis Epidemiology and life cycle

• Cercariae in fresh water penetrate human skin.
• Cercariae mature to schistosomulae, which enter
  the bloodstream, liver and lung.
• Mature worms migrate to the venous system of the
  small intestine (S. japonicum), large intestine
  (S. mansoni) or bladder venous plexus (S.
  haematobium).

155
Schistosomiasis Epidemiology and life cycle

• Worms release eggs for many years into stool or
  urine, resulting in fresh water contamination.
• Freshwater snails are infected by miracidia and
  are necessary for the production of cercariae and
  human infection.
• S. mansoni
• South America, Caribbean, Africa, Mid East
• S. japonicum
• China and Philippines
• S. haematobium
• Africa, Mid East

156
Schistosomiasis Clinical manifestations

• Three stages of disease, corresponding to life
  cycle within human hosts
• Swimmers itch
• Within 24 hours of cercariae penetration
• Serum sickness syndrome (Katayama fever)
• 4 to 8 weeks later when worms mature and release
  eggs
• Fever, headache, cough, chills, sweating,
  lymphadenopathy, hepatosplenomegaly ? usually
  resolves spontaneously
• Elevated IgE and eosinophils
• Most common with S. japonicum

157
Chronic Schistosomiasis

• Granulomatous reaction to egg deposition in
  intestine, liver, bladder, lungs
• S. mansoni, japonicum
• Chronic diarrhea, abdominal pain, blood loss,
  portal hypertension, hepatosplenomegaly,
  pulmonary hypertension
• Eosinophilia is common
• Liver function tests are usually normal
• S. Haematobium
• Hematuria, bladder obstruction, hydronephrosis,
  recurrent UTIs, bladder cancer

158
Schistosomiasis Diagnosis and Treatment

• Detection of characteristic eggs in stool, urine
  or tissue biopsy is diagnostic
• Urine is best between 12N and 2Pm, passed through
  10 µm filter to concentrate eggs
• Antibody tests are available, but limited by
  sensitivity, specificity
• Praziquantel is the drug of choice

159
(No Transcript)
160
S. haematobium Urine
S. japonicum
S. mansoni Stool
161
Case 18

• 15-yr-old girl
• Fever, rash, swelling around the eye and hands,
  severe headaches
• Fatigue, aching muscles and joints
• Swollen lymph nodes on the back of neck
• Weight loss
• Progressive confusion, personality changes
• Sleeping for long periods of the day
• Insomnia
• Had been on a safari with parents to West Africa
• Dusky red lesion developed within 1 week
• Vaguely remembered being bitten by a fly

162
Diagnosis?
163
Investigations

• Blood films
• Lumbar puncture

164
Blood smear
165
African trypanosomiasis

• Trypanosoma brucei gambiense

166
Tsetse fly
167
Treatment

• Suramin
• Melasoprol

168
Case 19

• 6-yr-old boy recently arrived from Brazil
• Swelling around the eye
• Conjunctivitis
• Fever
• Enlarged lymph nodes
• Hepatosplenomegaly
• Had stayed in a hoteladobe style with thatched
  roof

169
(No Transcript)
170
Diagnosis?
171
Blood smear
172
Reduviid bug(assassin bug)
173
Chagas disease Clinical manifestations

• Local edema is followed by fever, malaise,
  anorexia
• More rarely myocarditis, encephalitis
• Years later chronic Chagas Disease (10-30)
• Heart primary target
• Cardiomyopathy associated with CHF, emboli,
  arrythmias
• GI tract mega-esophagus, megacolon

174
Chagas disease Diagnosis and treatment

• Acute disease is diagnosed by seeing
  trypomastigotes on peripheral blood smear
• Chronic disease is diagnosed by ELISA detecting
  IgG antibody to T. cruzi
• Treatment slows the progression of heart disease

175
Chagas Disease

• Public health implications in the US
• Chronic
• Cardiomyopathy
• Megaesophagus
• Megacolon
• Blood transfusion
• Transplant
• Solid organ
• Musculoskeletal allograft tissue

176
Case 20

• 20-yr-old male
• Abdominal pain and nausea for several months
• More common in the morning
• Relieved by eating small amounts of food
• Some diarrhea and irritability
• Weight loss
• Pruritus ani
• Passage of white bits

177
(No Transcript)
178
Diagnosis?
179
Taenia saginata

• Ingestion of raw or poorly cooked beef
• Cows infected via the ingestion of human waste
  containing the eggs of the parasite
• Cows contain viable cysticercus larvae in the
  muscle
• Humans act as the host only to the adult
  tapeworms
• Up to 25 meters in the lumen of intestine
• Found all over the world, including the U.S.

180
Beef Tapeworm
181
Treatment

• Praziquantel
• Albendazole
• Niclosamide

182
Tapeworms (Cestodes)

• Adult worms inhabit GI tract of definitive
  vertebrate host
• Larvae inhabit tissues of intermediate host
• Humans
• Definitive for T. saginata
• Intermediate for Echinococcus granulosus
  (hydatid)
• Both definitive and intermediate for T. solium
• Adult worms shed egg-containing segments in stool
  ingested by intermediate host larval
  form in tissues

183
Case 21

• A 33 year-old Indian man was admitted with a
  grand mal seizure
• 2 yrs PTA, he had vertigo and CT revealed an
  enhancing calcified lesion in left
  temporal-parietal region
• FHx Brother had grand mal seizure several years
  earlier
• Throughout his life, he has eaten a diet heavy in
  pork

184
Case 21

• Difficulty speaking and loss of consciousness
  while on the phone
• Co-workers noticed generalized tonic-clonic
  seizures lasting 10 minutes.
• CT revealed new localized edema around the
  previously identified lesion and a second
  contiguous ring enhancing lesion.
• He received phenytoin (Dilantin, an antiseizure
  med) and 5 days of corticosteroids.

185
(No Transcript)
186
Case 21

• ELISA titer was positive for antibodies against
  Taenia solium.
• The neurosurgeons tell you that resection is
  impossible because of the extent and location of
  the lesion

187
Cystercercosis

• Human infected with the larval stage of Taenia
  solium
• Humans can serve as definitive or intermediate
  host
• Eggs are ingested, or possibly get to stomach by
  reverse peristalsis
• Probably much more common than is reported, since
  most infections are asymptomatic

188
Cystercercosis

• Symptoms depend on location of cysts, but
  frequently include motor spasms, seizures,
  confusion, irritability, and personality change
• In the eye, often subretinal or in vitreous.
  Movement may be seen by the patient. Pain,
  amaurosis, and loss of vision may occur.

189
Cysticercosis

• Clinical manifestations
• Adult worms rarely cause sxs
• Larvae penetrate intestine, enter blood, and
  eventually encyst in the brain.
• Cerebral ventircles ? hydrocephalus
• Spinal cord ? compression, paraplegia
• Subarachnoid space ? chronic meningitis
• Cerebral cortex ? seizures
• Cysts may remain asymptomatic for years, and
  become clinically apparent when larvae die
• Larvae may encyst in other organs, but are rarely
  symptomatic

190
Cysticercosis

• Diagnosis
• CT and MRI preferred studies
• Discrete cysts that may enhance
• Usually multiple lesions
• Single lesions especially common in cases from
  India
• Older lesions may calcify
• CSF
• Lymphs or eos, low glucose, elevated protein
• Serology
• Especially in cases with multiple cysts

191
Cysticercosis

• Treatment
• Complex and controversial
• Praziquantel and albendazole may kill cysts, but
  death of larvae can increase inflammation, edema
  and exacerbate sxs
• When possible, surgical resection of symptomatic
  cyst is preferred
• Corticosteroids vs. edema and inflammation
  antiseizure meds

192
(No Transcript)
193
(No Transcript)
194
Case 21

• He was not treated with praziquantel or
  albendazole
• He continued to receive dilantin for seizures and
  was treated with corticosteroids for edema

195
Classification of Parasitic Diseases

• Protozoa amoeba flagellates ciliates
• Metazoa (two phyla)
• Helminths (worms)
• Nematodes
• Intestinal
• Extra-intestinal
• Flatworms (platyhelminths)
• Cestodes (tapeworms)
• Trematodes (flukes)
• Arthopods (ectoparasites) scabies, lice, fly
  larvae

196
General rules of treatment

• Protozoa require species-specific treatment
• Metozoa species-specific

197
General rules of treatment of metazoa
198
This is just the beginning of a great adventure
in infectious diseases

• Sine qua non
• history and physical examination

199
Thank you

• Lennox K. Archibald, MD, PhD, FRCP
• lka1_at_ufl.edu