protozoan disease

PROTOZOAN DISEASES

AMEBIASIS:

Etiology: 2 morphologically identical but genetically distinct sp:

1. E. dispar = more prevalent sp.2. E. histolytica = pathogenic sp.

= symptomatic disease

Can be killed by heating to 550C

Resistant to low temperature and chlorine

Epidemiology:

Prevalence of 5 – 81%

Humans – major reservoir

Means of infection: food and drink contaminated with E. cyst in direct fecal – oral route

Pathogenesis:

Trophozoites Galactose – specific lectin

receptor Colonic mucosa

Cysteine – rich proteinase Tissue destruction

(flask-shaped ulcers)

Commonly invade:-cecum -transverse colon -sigmoid colon

Clinical Manifestations:

Intestinal Amebiasis:

incubation period = 2 weeks gradual onset, colicky abdominal pain, frequent bowel movementassociation with tenesmus stools blood stained, fair amount of mucus, few

leukocytes 1/3 of pts with fever amebic colitis = affects all age group

= increased incidence 1-5 y.o.

Hepatic Amebiasis:

< 1% infected fever is hallmark assoc. with abdominal pain, distention, enlargement and tenderness of liverlab findings: sl. Leukocytosis

moderate anemia inc. ESR inc. Alkaline phosphate >50% (-) stool exam

computed tomography and MRI – localize and delineate size of abscess cavity

Diagnosis:Stool exam – 3X (90% sensitivity) Sigmoidoscopy Tissue biopsy Aspirate of liver abscess Antigen detection tests – differentiate E. dispar from E. histolytica

Treatment: Luminal Amebicides 1. Iodoquinol 2. Paromomycin 3. Diloxonide furoate

Extraluminal Amebicides: 1. Metronidazole

2. Nitroimidazole

3. Chloroquine

4. Dehydroemetine

All individuals with E. histolytica trophozoites or cysts in their stools, whether symptomatic or not, should be treated

Iodoquinol - asymptomatic carriers - 30-40 mg/k/24 hours in 3 divided doses orally X 20 days

Paromomycin - non-absorbable aminoglycoside - 25-35 mg/k/24 hours in 3 divided doses orally X 7 days

Metronidazole- tissue amebicidal drug - 30-50 mg/k/24 hours in 3 divided doses

(max. 500-750 mg/dose) orally X 10 days - A. R. nausea, abdominal discomfort, metallic taste

Dehydroemetine – Metronidazole – resistant to E. histolytica

- 1 mg/k/24 hours (IM, SQ) Chloroquine - for amebic hepatic abscess

Stool exam should be repeated every 2 weeks until (-)

Prognosis: = death occurs in 5% having extraintestinal

infection

Prevention: 1. proper sanitary measures 2. avoiding fecal – oral contact 3. regular exam. of food handlers

No prophylactic drug or vaccine available

GARDIASIS:

Giardia lamblia = flagellated protozoan infecting duodenum and S. I.

= clinical manifestation from asymptomatic to acute or chronic diarrhea and

malabsorption

= significant pathogen with malnutrition,

immunodeficiency and cystic fibrosis

Life Cycle: Composed of 2 stages:

1. trophozoites 2. cysts

Ingested cyst (10-100 cysts)

2 trophozoite in S. I

Excystation

Lumen of duodenum and proximal jejunum

stools (2 mos.)

viability not affected by usual chlorine conc.

Epidemiology:

inc. in childhood and decreased in adolescents

water contaminated with G. cyst – major reservoir

foodborne transmission is documented

resistant to UV light irradiation

boiling effective for inactivating cysts

person-person spread in low hygiene, lack of toilet training child care centers

Clinical Manifestation:

inc. period = 1-2 but may be longer asymptomatic, excretion, acute infectious diarrhea, chronic diarrhea no extraintestinal spread but may migrate to bile and pancreatic ducts signs and symptoms: with or without fever, nausea, anorexia, diarrhea and abdominal distention and cramps stools profuse and watery and later greasy and foul smelling, no mucus, blood or fecal leukocytes

Diagnosis:

Definitive: cysts or trophozoites in stools or duodenal fluid by DFS (within 1 hour) Cyst – infectious form Others: Aspiration or Biopsy of duodenum or upper jejunum

Enterotest Polymerase Chain Reaction (PCR) for environment

monitoring Gene probe-based detection system

DFS – 70% diagnosis single exam 85% 2nd stool exam >90% 3rd stool exam

Medications can interfere presence of parasite in stool Radiographic: irregular thickening of mucosal folds NO blood count: NO eosinophilia

Treatment: Metronidazole – drug of choice Paromomycin Furazolidone – 92% cure rate

Prevention: 1. .Strict hand washing after contact with feces 2. .Adequate purification of water supply 3. .Travelers advice to avoid uncooked foods

BALANTIDIASIS:

Balantidium coli - ciliated protozoan - largest protozoan - close assoc. with pigs

(host of org.) - infects L. I.

Symptoms similar with Amebiasis

No extraintestinal spread

Diagnosis: Direct Saline Smear – trophozoites and cysts

Treatment:

1. Metronidazole (35-50mg/k/24hrs) divided by doses

(max. dose 750mg/day) orally X 5 days

2. Tetracycline (40mg/k/24hrs) divided by 4 doses (max. dose 500mg/dose) orally X 10 days in > 8 years

3. Iodoquinol (40mg/k/24hrs) divided by 3 doses (max. dose 650mg/dose) orally by 20 days

Prevention: Prevent contamination of the environment by pig

feces

SPORE – FORMING INTESTINAL PROTOZOA

1. Cryptosporidium

2. Isospora digestive tract

3. Cyclospora

4. Microsporidia – many organ systems - broad spectrum of disease

I. CRYPTOSPORIDIUM:Leading cause of diarrhea in children worldwide Common cause of outbreaks in child care centers

Etiology:Cryptosporidium parvum Infection due to infectious oocyst 2 stages:

a)Asexual – autoinfection at luminal surface of epithelium

b) Sexual – production of oocysts Cysts immediately infectious

Epidemiology:

In developing countries and <2 years of age

Etiologic agent of persistent diarrhea

Transmission: - contact with infected animals

- person to person

- contaminated water - zoonotic (cows)


Incubation period – 2-14 days Profuse, watery, non-bloody diarrhea, diffuse crampy abdominal pain, nausea, vomiting and anorexia Non-specific symptoms: myalgia, headache, weakness

fever – 30-50% cases malabsorption, lactose intoerancedehydration, weight loss, malnutrition–

in severe cases In immunocompromised hosts:

= assoc. with biliary tract disease = fever ® upper quadrant pain, nausea, vomiting and diarrhea = detected in pancreatic duct of child with AIDS

Diagnosis:

Self-limited

Supportive care

Immunocompromised: Paromomycin (25-35mg/k/24hrs)

4 doses orally Paromomycin (1g/day) and Azithromycin (600mg daily) followed by

Paromomycin monotherapy X 8 weeks in adult patients with AIDS

II. ISOSPORA:

Isospora belli Diarrhea in intestinal outbreaks, travelers, contaminated water and food More common in tropical and subtropical climates Not assoc. with animal contact May infect 15% of AIDS patients Life cycle same with Cryptosporidium except oocysts are not immediately infectious and must undergo maturation below 37OCClinical manifestation: indistinguishable from

Cryptosporidiosis but fever is more common Eosinophilia may be present

Diagnosis: AFS of stool Fecal leukocytes not detected

Treatment:

1. Trimethoprim – Sulfamethoxazole (TMP – SMZ) (5mg TMP, 25mg SMZ/k/dose) max.

160mg TMP, 800mg SMZ/dose orally 4 X/day X 10 days then 2 X a

day X 3 weeks

2. Pyrimethamine alone or Folinic acid – in patients intolerant of Sulfonamide drugs

III. CYCLOSPORA:

Cyclospora cayetanensis–AKA cyanobacterium– like bodyCommon in <18 months of age Pathogenesis and path. findings similar to isosporiasis Patients almost always have diarrhea Linked to contaminated food and water Clinical manif. similar to Crypto and Isosporiasis Moderate illness: Median of 6 stools/day with median duration of 10 day (range 3 – 35 days)

Assoc. symptoms: fatigue, abdominal bloating or gas, abdominal cramps, nausea, muscle joints and pains, fever, chill and weight loss

Oocysts remain infectious for days to weeks

Diagnosis: Ident. of oocysts in stool - modified AFS

- phenosafranin stain - autofluorescence

Fecal leukocytes not present

Treatment: TMP – SMZ (5mg TMP, 25mg/k/dose SMZ)

2X/day; max. 160mg TMP, 800mg SMZ/dose orally X 7 days

IV. MICROSPORIDIA:

Infect most animal groups including humans Assoc. with GI disease:

a) Enterocytozoon beineusi b) Septata intestinalis

Spores inject contents to host cells to cause infection Spores detected in urine and resp. epithelium Spores remain infectious up to 4 monthsAlmost exclusively reported in patients with AIDS Diarrhea is intermittent, copious, watery and non-bloody Biliary disease can occur

Diagnosis: Hematoxylin – Eosin Periodic acid – Schiff (PAS) Giemsa and Gram stain AFS Electron Microscopy

Treatment: No proven therapy Albendazole (adult dose: 400mg 2X/day X 4 weeks) Atovaquone – dec. symptoms, no clinical trials

TRICHOMONIASIS

Trichomonas vaginalis Sexually transmitted >60% - female partners of infected men 30 – 80% male sexual partners of infected women rare in menarche: if (+) in younger child – a possibility of sexual abusecan be transmitted to neonates thru infected birth canal

pathogenesis:Vaginal secretions – 101 – 105 or more

protozoa/ml pear-shaped

clinical manifestations:-incubation period – 5 – 28 days -10% - 50% asymptomatic female -copious, malodorous yellow vaginal discharge -vulvovaginal irritation -dysuria, dyspareunia -P.E: frothy discharge with vaginal erythema and

cervical hemorrhages (“strawberry cervix)

Most males are asymptomatic

5 – 15% of men with non-gonococcal urethritis

Symptomatic males: Dysuria Scant urethral discharge – 36% resolve

spontaneously

Diagnosis: Demonstration of protozoan in genital secretions Wet mount technique = 60-70% infected females

= 50-90% infected men

A (-) wet mount method does not rule out diagnosis of trichomoniasis

Culture of the organism = most sensitive

= >95% sensitive = not routinely available

Treatment:1. Nitroimidazole 2. Metronidazole 3. Tinidazole 4. Ornidazole

Metronidazole = 2g orally single dose in adoles females

250mg 3X/day or 375mg 2X/day orally X

7days in infected children – 15mg/k/24hrs / 3 doses orally X 7 days

All sexual partners should be treated

It is now recommended to treat trichomoniasis during pregnancy – safe in last 2 trimesters

TOXOPLASMOSIS:

Toxoplasma gondiiAcquired perorally, transplacentally, rarely parenterally, transfusion, transplacented organ Organism persist for lifetime Organism remain in tissues especially CNS, skeletal and heart muscles oocysts excreted by infected cats Cat excreted 105 – 107 oocysts/day Acquired by oral route via uncooked or raw meat

containing cysts or by ingestion of oocysts

= pork – 5.35%= lamb – 60% = beef – 0-9%

Freezing meat – 200C or heating 600C – uninfectious

Pathogenesis:

Ingestion of Oocysts

bradyzoites released from cyst

sporozoites from oocysts

GIT lymphatics

disseminate throughout body

- pneumonitis- myocarditis- necrotizing encephalitis

Congenital Toxoplasmosis:

Mother acquires infection during gestation

Disseminate hemaatogenously to placenta (transplacentally) or during

vaginal delivery

1st trimester – 17% infected

3rd trimester – 65% infected

almost all infected fetuses manifest chorioretinitis by adolescence


Acquired Toxoplasmosis:fever, stiff neck, arthralgia, maculopapular rash sparing palms and soles, localized or gen. lymphadenopathy, hepatomegaly, hepatitis, meningitis, brain abscess, pneumonia, pericardial effusion, myocarditis

Ocular Toxoplasmosis:blurred vision, photophobia, loss of central vision strabismus, microophthalmia, microcornea, cataract, nystagmus

Congenital Toxoplasmosis:

SKIN: rashes, petechiae, ecchymoses, large hemorrhages 20

thrombocytopeniaJaundice due to hepatic involvement

Systemic signs: Endocrine: hypothalamic or pituitary involvement

myxedema, persistent hypernatremia, D.I. without polyuria –

polydispsia, sexual precosity

CNS: hydrocephalus, seizures EYES: chorioretinal lesions – 50% severe visual

impairment EARS: Sensorineural hearing loss

Diagnosis: 1. Culture – isolation from blood or body fluids

- demo. of tachyzoites in tissues and body tissues - cysts in placenta or tissues of fetus

2. Serologic testing:a) Sabin-Feldman dye test – sensitive & specific - measures IgG antibodies b) IgG – indirect fluorescent – antibody (IgG – IFA)

- does not correlate severity of illness c) Agglutination test – detect IgM antibodies d) IgM – IFA – dx of acute infection in older children e) Double Sandwich ELISA – more sensitive and

specific than IgM-IFA test f) Immunosorbent agglutination assay (ISAGA) g) Indirect hemaglutination (IHA) measures diff. T.

gondii antibodies

Treatment: 1. Pyrimethamine + Sulfadiazine or Trisulfapyrimidines

= act synergistically = treat many forms of toxoplasmosis

2. Spiramycin – prevent transmission of infection to fetus

Acquired Toxoplasmosis: Pyrimethamine – 2mg/k/24hrs (max.

50mg) 1st 2 days 1mg/k/24hrs (max. 25mg/24hrs)

Folinic Acid – 5-20mg 3X/week orally Sulfadiazine – in >1year of age

- 75mg/k/24hrs LD then 50mg/k/24hrs

Ocular Toxoplasmosis:Pyrimethamine Sulfadiazine 1 week Leukovorin

Congenital Toxoplasmosis: should be treated for 1 year

Oral Pyrimethamine – 1-2mg/k/24hrs X 2days then,

1mg/k/24hrs X 2 or 6months then, 1mg/k/24hrs M – W – F

Sulfadiazine – 100mg/k/24hrs LD100mg/k/24hrs / 2 doses

Calcium leukovorin – 5 –10mg/k/24hrs M-W-F

Pregnant Women with Toxoplasmosis:Spiramycin and Pyrimethamine + Sulfadiazine

= reduces infection in placenta and severity of disease

Spiramycin – 1g every 8hrs. without food

Prognosis: Early treatment for congenital infection cures manifestations Guarded – infected babies

Prevention:1. Counseling women about methods of

preventing transmission of T. gondii during pregnancy

2. Eat well cooked meat 3. Avoid contact with oocysts excreted by cats

PNEUMOCYSTIS CARINII

Pneumocystis carinii pneumonia (interstitial plasma cell pneumonitis)

Extracellular parasite of the lungs

Epidemiology: Mostly affected - <4years of age Immunocompromised patient - 40%

= infants and children 70% = adults with AIDS 12% = leukemia 10% = organ transplant

Pathogenesis: 2 types of histopathologic features of P. carinii pneumonia:

a) infantile interstitial plasma cell pneumonitis = 3-6mos. of age

b) diffuse desquamative alveolar dis. = immunocompromised children and

adult

Clinical Manifestation:Tachypnea without fever intercostal, suprasternal and infrasternal retractions nasal flaring cyanosis rales not detected chest radiograph: bilateral diffuse alveolar disease with granular pattern

Diagnosis:

demonstration of P. carinii in the lung

1) bronchoalveolar lavage

2) tracheal aspirate

3) transbronchial lung biopsy

4) bronchial brushings

5) percutaneous transthoracic needle aspiration

6) open lung biopsy – most reliable

Treatment:TMP – SMZ – (15-20mg TMP, 75-100mg SMZ/k/24hrs) 4 doses

IV or orally = 3 weeks with AIDS 2 weeks in other patients

Pentamidine isethionate (4mg/k/24hrs) SD IV – resistant to TMP –

SMZ

Prednisone = inc. survival rate in mod. – severe infections

= >13 years old–80mg/24hrs/ 2 doses 1–5 days

40mg/24hrs 6 – 10th days

20mg/24hrs 11 – 21st days

= children – 2mg/kg/24hrs 1st 7 – 10 days

taper next 10-14 days

Prognosis:

without treatment – fatal

10 – 30% mortality rate

chemoprophylaxis - TMP – SMZ Dapsone Aerosolized pentamidine

MALARIA (PLASMODIUM)

acute and chronic protozoan illness charac. by paroxysms of fever, chills, sweats, fatigue, anemia and splenomegaly

Etiology: Plasmodium protozoa Transmitted to humans by female Anopheles mosquito 4 species:

1. P. falciparum 2. P. malariae 3. P. ovale 4. P. vivax

Life Cycle:a) Asexual phase – in human host b) Sexual phase – mosquito

Exoerythrocytic phase = cells in the liver Erythrocytic phase = in rbc’s

Exoerythrocytic phase:

Inoc. of sporozoites to blood stream by Female Anopheles mosquito

Hepatocytes (multiply asexually)

Schizont (1-2 weeks)

Rupture of hepatocytes

Release of merozoites to circulation

Erythrocytic phase:

Merozoites from liver center erythrocytes

Ring formation _____trophozoite

Multiply to form erythrocytic merozoite

bloodstream

rbc membrane rupture (fever)

ingested by mosquito

male and female gametocyte fuse to form

zygote

sporozoites enter the salivary glands of mosquito

Epidemiology:Transmitted through blood transfusion, use of contaminated needles, pregnant woman to her fetus

Pathogenesis:

4 important pathologic process:a) fever = when the rbc ruptures and merozoites

are released b) anemia = hemolysis, sequestration of rbc’s in the

spleen and other organs, suppression of the rbc prod. in BM c) immunopathologic events = formation of immune

complexes, immuno-suppresion, release of cytokines

(TNF) d) tissue anoxia = resulting from cytoadherence of

infected erythrocytes

= occur in P. falciparum malaria

• Clinical Manifestations:Incubation period:1. P. falciparum = 9-14 days2. P. vivax = 12-17 days or as long as 6-12

months3. P. ovale = 16-18 days4. P. malariae = 18-40 days

Prodromal symptoms = 2-3 days= headache, fatigue, anorexia, myalgia, slight fever, pain in chest,

abdominal and joint pains

• P. falciparum = most severe form

= infects both immature and mature erythrocytes

P. ovale & vivax = infects immature rbc’s

P. malariae = infects mature erythrocytes

= mildest & most chronic

P. ovale = least common type

= in conjunction with P. falciparum

• Diagnosis of P. falciparum malaria constitute a medical emergency

• Diagnosis:

Giemsa-stained peripheral smear

thick smear = scan large no. of rbc’s quickly

thin smear = identification of malaria species & determine % of infected erythrocytes

• A single negative blood smear does not rule out malaria

• Other tests:

Monoclonal Antibody test = as sensitive as thick smear

PCR

• Treatment:

1. Therapeutic

- Chloroquine phosphate = oral DOC

- Quinidine gluconate = IV DOC

2. Supportive

1. blood transfusion to maintain hematocrit

of >20%

2. exchange transfusion in P. falciparum malaria with parasitemia of 15%

3. careful IV rehydration

4. supplemental oxygen + ventilatory support for pulmonary edema or cerebral malaria

5. IV glucose for hypoglycemia6. anticonvulsants7. dialysis for renal failure

Complications:1. cerebral malaria = 20-40% fatality rate2. renal failure3. “Blackwater fever” = clinical syndrome that

consist of sevre hemolysis, hemoglobinuria and renal failure

• Prevention:

1. reducing exposure to infected mosquitoes

2. travelers to endemic areas should remain in well screened areas

3. using of mosquito repellants

4. use of chemoprophylaxis

SCHISTOSOMIASIS

Etiology:

Schistosoma sp:

1.S. haematobium

2.S. mansoni

3.S. japonicum

4.S. intercalatum

5.S. menkongi

Flukes or trematodes that parasitize bloodstream

Cercariae – infective stage

Anatomic sites migrated by schistosoma S. haematobium – perivesical and periureteral venous plexus S. mansoni – inferior mesenteric veins S. japonicum – superior mesenteric veins S. intercalatum and mekongi – mesenteric vessels

Charac. egg morphologic features: S. mansoni – lateral spine S. haematobium – terminal spine S. japonicum – smaller size and short curved spine

Humans – only definitive host

Clinical Manifestations:Papular pruritic rash (schistosomal dermatitis or

swimmer’s itch)Katayama fever = serum sickness – like syndrome

- acute onset of fever, chills, sweating, lymphadenopathy,

hepatosplenomegaly, eosinophilia S. japonicum – may migrate to brain vasculature

Diagnosis: Kato’s thick smear

Treatment: Praziquantel

TRICHINOSIS

Etiology: Trichinella spiralis

Transmitted by ingestion of pork or other meat carrying

parasite

Larva penetrate gut wall, striated muscle, CNS, heart

Clinical manif: 1st week = gastroenteritis

muscle = periorbital, facial edema, myalgia

= common in masseters, diaphragm, intercostals

Diagnosis: - periorbital edema - myalgia fever - eosinophilia

- muscle biopsy - bentonite flocculation test- inc. creative kinase + lactose

dehydrogenase = 50%

Treatment:Mebendazole – eliminate adult worm from gut

TRICHURIASIS

Etiology: Trichuris trichiura or whipworm Final habitats: cecum and ascending colon Clinical manif: abdominal pain, colic, distention Adult worm suck 0.005ml of blood/worm/day

Anemia, blood diarrhea, rectal prolapse – massive infantile trichuriasis

Associated with Shigellosis and protozoan infections of GIT Treatment: Mebendazole – 70 – 90% cure rate

- 90 – 99% reduce egg output

- 100mg bid X 3 days or 500mg once a day

Albendazole – alternative - 400mg X 3 days

STRONGYLOIDIASIS

Etiology: Strongyloides stercoralis Filariform larva Capable of infecting same individual (autoinfection) Pathogenesis: Dermatitis – repeated skin penetration

- larva currens Loffler’s Syndrome

Clinical manif: Pruritus and popular erythematous rash Abdominal pain, vomiting, diarrhea Diagnosis: feces or duodenal fluid for larva Treatment: Ivermectin – 200mg/k/24 hrs X 1-2 days Thiabendazole – 50mg/k/24 hrs divided by

2 doses X 2 days

LYMPHATIC FILARIASIS

Etiology: 1. Brugia malayi (Malayan filariasis) 2. Wuchereria bancrofti (Bancroftian filariasis)

Characterized by: - lymphadenitis - lymphangitis - lymphatic obstruction and

hydrocoele - elephantiasis

Clinical manifestation: -Fever -Lymphangitis of extremity -Lyphadenitis -Headaches, myalgias

Diagnosis: Blood – microfilariae

Treatment: 1. Diethylcarbamazine – modifies course of acute

lymphangitis 2. Ivermectine

HELMINTHIC DISEASES

Ascariasis: Ascaris lumbricoides Common in pre-school and early school age

Etiology:Mature larva containing egg – infective stage Female – life span 1-2 years

200,000 eggs/24 hours

Epidemiology:MOT– hand–mouth, fingers contaminated by soil contactFoods - raw

Pathogenesis:

Ingested eggs

larva

intestinal wall pulmonary tissues

alveolar spaces

bronchial tree and

trachea

re-swallowed

Clinical Manifestation: Pulmonary ascariasis: Cough blood-stained sputum +

Eosinophilia = Loeffler’s – like

Syndrome GI : Abdominal pain and distention

Intestinal obstruction – 1-6 year old ,sudden, severe, colicky

abdominal pain and vomiting (bile –

stained)

Diagnosis: DFS Kato’s thick smear method Pulmonary ascariasis or GI is based on clinical symptoms and high index of suspension

Treatment:1. Albendazole – 400mg PO SD 2. Mebendazole – 100mg BID X 3 days 500mg once 3. Pyrantel pamoate – 11mg/k once (max.1g) PO

4. Piperazine – 50-75mg/k X 2 days PO- neuromuscular paralysis and expulsion of parasite

Prevention: 1. Deworming every 3-6 months 2. Improve sanitary practices

HOOKWORMS

Ancylostoma Necator americanus

Etiology: 1. Ancylostoma:

a) A. duodenale – classical hookworm infection b) A. ceylanicum c) A. caninum – eosinophilic enteritis syndrome d) A. braziliense – cutaneous larva migrans

2. Necator americanus – anthropophilic hookworm = infect humans thru skin penetration

Pathogenesis:

• adhere to mucosa & submucosa of S.I. (cutting plates) = causes intestinal blood loss

•In moderate to severe infections: Anemia + IDA


• “ground itch” = skin penetration

• Cough = Laryngotracheobronchitis; pharyngitis

• Chronic: Chlorosis – yellow green pallor

• Malnutrition

Diagnosis :

• DFS

• Colonoscopy

Treatment:

• !. Nutritional support

• 2. Albendazole

• 3. Mebendazole

• 4. Pyrantel pamoate

Prevention:

• 1. Sanitation

• 2. Health education

• 3. Avoidance of human feces as fertilizers

ENTEROBIASIS (Pinworm Infection)

• Enterobius vermicularis

• Embryonated egg in fingernails, clothing, beddings or house dust

• Gravid female migrate by night to perianal region

• Humans = only natural host

• High in 5-14 years of age


• nocturnal anal pruritus

• sleeplessness

Diagnosis:

• parasite eggs or worms in stools

• pressing adhesive cellophane tape technique

Treatment:

• 1. Albendazole

• 2. Mebendazole

• 3. Pyrantel pamoate

•Repeat treatment after 2 weeks

TOXOCARIASIS:

• Visceral larva migrans

= < 10 yrs of age

= fever, hepatomegaly, pulmonary disease & eosinophilia

= Toxocara cati – feline ascarid

= Toxocara canis – canine ascarid

Clinical manifestations:

• fever = 80%

• cough with wheezing = 60-80%

• seizures = 20-30%

• Hepatomegaly = 65-87%

• rales or rhonchi = 40-50%

• urticarial rash = 20%

• lymphadenopathy = 8%

• decreased visual acuity = 75% (ocular larva migrans)

Diagnosis: ELISA

Treatment:

• In pulmonary disease: Prednisone

• Ocular Larva Migrans : Diethylcarbamazine

Albendazole

Mebendazole

Prevention:

• Wash hands after playing with pets

• Periodic deworming of dogs & cats

TAPEWORM INFECTIONS

TAENIASIS:

1. Taenia saginata = beef tapeworm

2. Taenia solium = pork tapeworm

Difference:

T. saginata = 4 anterior suckers

= > 20 uterine branches

T. solium = scolex with double row of hooks

= < 10 uterine branches

Treatment: Preaziquantel

DIPHYLLOBOTHRIASIS:

• Diphyllobothrium latum = fish tapeworm

= longest human tapeworm

• Uses Vitamin B12 for production of segments

• Inhibits Vitamin B12 uptake by inactivating Vit. B12 intrinsic factor

• Megaloblastic anemia

• Treatment: Praziquantel = 5-10 mg/k P.O. single dose

HYMENOLEPIASIS:

• Hymenolepis nana = dwarf tapeworm

= in rodents, ticks, fleas

= poor hygienic conditions

Treatment:

•Praziquantel

•Niclosamide

DIPYLIDIASIS:

• Dipylidium caninum = tapeworm of domestic dogs & cats

Treatment: Praziquantel

CYSTICERCOSIS:

•Infection due to T. solium

•Common parasitic cause of CNS disease (Neurocysticercosis)

•Invade primarily the brain and muscle tissues


• seizures – primary finding

- 70% of cases

- 80% generalized

- initially simple or complex partial

•4th ventricle = most common site of obstruction

Diagnosis:

• CT scan

•EITB (Enzyme Linked Immunotransfer Blot)

Treatment:

•Albendazole

•Corticosteroids

ECHINOCOCCOSIS:

•Hydatid disease of Hydatidosis

•Most serious human cestode infection

•Echinococcus species:

1. E. granulosus = unilocular or cystic hydatid disease

2. E. multiformis = alveolar hydatid disease

•Lungs = commonly affected

•Right lobe of the liver = 70% affected in adults

Treatment:

•Surgery = in alveolar hydatidosis

•Prophylactic Albendazole

MYCOTIC INFECTIONS

Neonatal Infections:

•Candida species = common cause

•Oral thrush & diaper dermatitis

•Isolated from GIT & vaginal flora

•10% term infants – GIT & respiratory tract

- 1st 5 days of life

•30% in <1,500 grams neonate

•Systemic infections in VLBW infants

Risk factors:

•Abdominal surgery

•Prolonged ventilatory support

•Prolonged IV catheterization

•Use of IV alimentation

•Administration of broad spectrum antibiotics


•Asymptomatic

•Associated with sepsis or shock in severe cases

•Disseminated candidiasis = mimics bacterial sepsis with respiratory distress, apnea, bradycardia, temperature instability, glucose intolerance, abdominal signs and symptoms

•Cutaneous: diffuse erythroderma or vesiculopustules

>50% renal involvement

•CNS – 1/3 of cases

- meninges, ventricles, cerebral cortex with abscess formation

•Endolphthalmitis = 20-50% of cases

•Candidal endocarditis = central venous catheters extending to atrium

•Pneumonia = 70% of cases

Diagnosis:

•Culture = body fluids

•Buffy coat smears = show yeast

= preliminary diagnosis

•Skin scrapings

•Ultrasonography = CV, renal, CNS

Treatment:

1. Amphotericin B = Drug of choice

= 0.5-0.1 mg/k/24 hrs IV

= active against yeast & mycelial forms

= duration of therapy depends on the extent of infection, clinical response, drug toxicity

= adverse reaction: Nephrotoxicity

2. Liposomal Amphotericin B = 5 mg/k/24 hr

= less renal toxicity

= in neonates with renal compromise

3, Flucytosine = 100-150 mg/k/24 hrs every 6 hrs P.O.

= CNS and parenchymal kidney infections

ORAL CANDIDIASIS:

•Oral thrush or oral pseumembranous candidiasis

•2-5% in newborns

•7-10 days of age

•Recurrent or persistent thrush = use of antibiotics during 1st year of life

•Removal of plaques causes bleeding = confirms the diagnosis

•Asymptomatic or with pain, causes decreased feeding

•No history of antibiotic intake = diabetes mellitus, HIV infection

Treatment:

•Mild = no therapy

•Severe = nystatin, Miconazole gel, Amphotericin B suspension, Gentian violet

DIAPER DERMATITIS:

•Complicates oral antibiotic treatment of otitis media

•Treatment: Nystatin cream, powder or ointment

1% Clotrimazole cream

2% Miconazole ointment

1% hydrocortisone = inflammation

VULVOVAGINITIS:

•Common in pubertal & post pubertal women

•Predisposing factors: pregnancy

oral contraceptive use

poor hygiene

use of oral antibiotics


•Pain or itching

•Dysuria

•Vulvar or vaginal erythema

•Cheesy exudate

•Thrush like mucosal palques

Treatment:

•Nystatin cream

•Clotrimazole

•Miconazole

•Fluconazole

CRYPTOCOCCOSIS:

•Cryptococcus neoformans =

•Soil contaminated with avian droppings, fruits & vegetables carried by cockroaches

•60% in adults

•5-10% in HIV infected adults

•Acquired by inhalation of fungal spores

•Disseminate into the brain, meninges, skin, eyes, skeletal; system

•Pulmonary cryptococcosis = granuloma

= subpleural location

= contain yeast forms

•CNS = cystic cryptococcomas

= 20% non-HIV infected patients


•Pneumonia = most common form

= fever, cough, pleuritic chest pain

= x-ray: poorly localized bronchopneumonia

•Disseminated infection = follows primary pulmonary disease

= in immunocompromised individuals

•Meningitis = sub acute or chronic

= headache as initial symptom – good outcome

= cryptococcal antigen titer < 1:32

= 15-30% mortality

= >50% relapse in HIV infection

•Skeletal infection = 5% of cases

= soft tissue swelling and tenderness

= arthritis ( effusion, erythema, pain on motion)

= vertebrae – common site

•Ocular infection = acute loss of visual acuity, eye pain, visual floaters, photophobia

= >20% mortality rate

= 15% recover full vision

Diagnosis:

•Cuture

•Histology

Treatment:

•In immunocompromised host with asymptomatic or mild disease = oral fluconazole (200-400 mg/24 hrs) for 3-6 months

•Immunocompetent with progressive pulmonary disease or non-HIV infected = Amphotericin B (15mg/k/24 max. 1.5 g total dose)

•CNS and disseminated infections = combination of Amphotericin B and Flucytosine

•Cutaneous infections = surgical biopsy for diagnosis and apply appropriate topical antifungals

•Skeletal = surgical debridement & systemic antifungal

•Chorioretinitis = amphotericin B + Flucytosine of Fluconazole

HISTOPLASMOSIS:

• Histoplasma capsulatum = contaminated bird droppings or decayed wood

• Often carried by wings of birds

• Resembles Ghon complex of TB

• 3 forms:

1. Acute pulmonary infection

2. Chronic pulmonary histoplasmosis

3. Progressive disseminated histoplasmosis

Acute Pulmonary Histoplasmosis:

•Follows initial or recurrent respiratory exposure to microconidia

•Flu-like symptoms: headache, fever, chest pain, cough

•Hepatosplenomegaly in children and infants

•In severe cases: respiratory distress, hypoxia – may require intubation, ventilation, steroid therapy

Chronic Pulmonary Histoplasmosis:

•Opportunistic infection in adults with centrilobular emphysema

•Rare in children

Progressive Disseminated Histoplasmosis:

•Affects infants & immunosuppressed individuals•Infants <1 year & follows primary pulmonary histoplasmosis•Fever = most common

= last for weeks to months•Hepatosplenomegaly, anemia, thrombocytopenia

Diagnosis:•Culture of bronchoalveolar lavage fluid•Culture of blood = >90% patients with progressive disseminated histoplasmosis

Treatment:•Amphotericin B = DOC•Ketoconazole•Itraconazole

MUCORMYCOSIS:

•Characterized by vascular invasion, thrombosis and necrosis

•Rhinocerebral and pulmonary infections – inhaled spores

•Occur in patients with leukemia, DM, Fanconi’s anemia

•Headache, retro orbital pain, fever, nasal discharge

•Nasal discharge = dark & bloody

•Nasal mucosa = black with necrotic areas

•Brain abscess may occur

•Pulmonary mucormycosis: fever, tachypnea, productive cough, pleuritic chest pain, hemoptysis

Diagnosis:

•Culture

•Histology

Treatment:

•Amphotericin B (1-1.5mg/k/24 hrs to a total dose of 70 mg/kg)

•Extensive surgical debridement

protozoan disease

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