Download Treat Fungal, Protozoal and Helminthic infections

Treat Fungal, Protozoal and Helminthic
Infections
003.11
Outline
• What is an opportunistic infection?
• Describe the epidemiology, signs and symptoms,
diagnosis, treatment and preventative measures of:
– Fungal infections
• Histoplasmosis
• Aspergillosis
• Systemic /Superficial Candidiasis
Outline
• Malaria
• Describe the the epidemiology, signs and symptoms,
diagnosis, treatment and prevention for:
– Amoebiasis, Giardiasis, Trichomoniasis,
Toxoplasmosis & Pneumocystis carnii
• Describe the epidemiology, signs and symptoms,
diagnosis, treatment and prevention for the following
helminthic diseases:
– Nematodes, Cestodes & Trematodes
Opportunistic infections
• Definition
– is any infection that results from a defective immune
system that is unable to defend itself against pathogens
found in the normal environment
– Host defence mechanisms such as physiologic,
anatomic or immunologic may be altered by disease,
trauma, procedures or agents used for diagnosis or
therapy
– Normally, fungal growth in the body is kept in check by
harmless bacteria that compete with the fungus for food
Deep Fungal Infections
• Histoplasmosis
• Aspergillosis
• Systemic Candidiasis
Histoplasmosis
• Has several forms
–
–
–
–
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asymptomatic
acute histoplasmosis
progressive disseminated
chronic progressive pulmonary
disseminated disease in the profoundly
immunocompromised
Histoplasmosis
• Treatment
– for progressively localized disease and for mild to
moderately severe nonmeningeal disseminated disease
in immunocompetent or immunocompromised patients:
• Itraconazole or Ketaconazole
• duration of therapy ranges from weeks to several
months depending upon severity.
Histoplasmosis
• Treatment
– for patients who cannot take oral medications, who
have failed itraconazole therapy or who have meningitis
and for management of severe disseminated disease in
an immunocompromised host:
• Amphotericin B up to 2.5 g total may be needed
• Oral itraconazole may be given once condition
stabilized
– patients with AIDs-related Histoplasmosis require
lifelong suppressive therapy with itraconazole
Histoplasmosis
• Prevention
– minimize exposure to contaminated areas such as caves
or chicken coop areas
– spray contaminated or suspect areas with water or oil
– wear protective masks
Aspergillosis
• Epidemiology & Etiology
– caused by
• Aspergillus Fumigatus, A. Niger, and A. Flavus
– infection caused by inhalation of mold, leading to
hyphal growth and invasion of blood vessels,
hemorrhagic necrosis, infarction and potential
dissemination to other sites in susceptible patients
Aspergillosis
• Epidemiology & Etiology
– found in world wide in decaying vegetation,
insulation, air conditioning or heating venting,
operating and patient rooms, on medical
instruments and in airborne dust
– acquired by inhalation or occasionally by direct
invasion in areas of damaged skin
– major risk factors include neutropenia, long term high
dose corticosteroid use, transplants, heredity disorders
or occasionally AIDs
Aspergillosis
• Treatment
• Fungal Balls
– do not respond to antifungal therapy
– resection may be required
• Invasive
– Amphotericin B
• Allergic
– oral prednisone
– Itraconazole
Aspergillosis
• Prevention
–
–
–
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monitoring of food with high levels of aflotoxins
avoidance
proper disposal of old foodstuff, decaying hay etc.
proper and regular maintenance of air conditioning and
heating units
– maintenance of good health
*Systemic Candidiasis*
• Epidemiology
– invasive infection caused by Candida causing:
• Esophagitis (most common)
• Hepatosplenic involvement
• Fungemia (presence of fungi in the blood)
• Endocarditis
• Meningitis
Systemic Candidiasis
• S&S
•
•
•
•
Esophagitis
Respiratory inf.
Endophthalmitis
Fungemia
• Endocarditis
- odynophagia, dysphagia
- nonspecific, such as cough
- white retinal plaques
- fever, fluffy white retinal infiltrates
-secondary to fungemia
Systemic Candidiasis
• Diagnosis
– cultures from sputum, mouth, vagina, urine, blood.
– presence of characteristic lesion
– positive cultures of blood, CSF, pericardium or
pericardial fluid or tissue biopsy specimens provide
definitive evidence
Systemic Candidiasis
• Treatment:
– all forms of disseminated candidiasis should be
considered serious, progressive and potentially fatal
– predisposing conditions such as neutropenia,
malnutrion, or uncontrolled diabetes should be reversed
whenever possible.
- Echinocandin (micafungin, caspofungin).
– IV Amphotericin B.
Systemic Candidiasis
• Prevention
– detection and treatment of oral or vaginal infections as
soon as possible
– maintenance of good health in immunocompromised
personnel i.e. Diabetics and HIV
Superficial Fungal Infections
Candidiasis
• Diagnosis
– Candida albicans can be cultured from the mouth,
vagina, urine and nails
– Vaginal smears reveal large ovoid cells
• Treatment:
– Fluconazole,
– Clotrimazole, Nystatin
– Itraconazole, Griseofluvin
Outline
• Malaria
– clinical presentation, pathophysiology, diagnostic criteria,
transmission and management of malaria sub-types
• PLASMODIUM Falciparum
• PLASMODIUM Vivax
• PLASMODIUM Ovale
• PLASMODIUM Malariae
• Plasmodium knowlesi
Malaria
• Epidemiology & Etiology
– a disease caused by a minute unicellular parasite
known as PLASMODIUM
– part of the life cycle is spent in man and part in the
mosquito
– major cause of ill health in many tropical and subtropical areas
– imported cases reported in Canada
– found worldwide due to imported cases
Malaria
• Epidemiology & Etiology
– although the disease has been eradicated from most
temperate zone countries, it continues to be endemic in
many parts of the tropics and subtropics & imported
cases occur in the USA & other countries free of
transmission
– especially dangerous to young children and pregnant
women
Malaria
• Endemic area: Malaria is present in parts of Mexico,
Haiti, Dominican Republic, Central & South
America, Africa, the Middle East, the Indian
subcontinent, Southeast Asia, China and Oceania
Malaria (Species )
•
Malaria has 4 different species
– most common are (>95% of clinical cases)
1. Plasmodium Vivax (80%)
2. Plasmodium Falciparum (15%)
– less common is
3. Plasmodium Malariae
– rare is
4. Plasmodium Ovale
Malaria
• Epidemiology & Etiology
– P. vivax & P. falciparum are responsible for most
infections & are found through out the regions which
have malaria
– P. falciparum is the predominant species in Africa &
the only plasmodium in Haiti & the Dominican
Republic
– P. malariae is also widely distributed but is less
common
Malaria
• Epidemiology & Etiology
– P.ovale although generally rare, seems to replace P.
vivax in West Africa.
– P.vivax infection is uncommon among black people
because their red blood cells do not have the Duffy
surface antigen, which is required for the invasion of
the RBC’s
– humans are the only important reservoirs for malaria
Malaria
• Transmission
– infected mosquito bites man and injects parasites into
blood stream
– congenital transmission
– blood infusion with infected blood
Malaria
• Incubation period
– Falciparum
• 12 days (7 - 25)
– Vivax and Ovale
• 14 days (8 - 27)
– Malariae
• 30 days (16 days - 8 wk)
Malaria
• Essentials for diagnosis
– history of exposure in a malaria-endemic area
– periodic attacks of sequential chills, fever & sweating
– headache, myalgia, splenomegaly, anemia and
leukopenia
– characteristic parasites in erythrocytes, identified in
thick or thin blood films
Malaria
• Essentials for diagnosis
– complications of P. Falciparum malaria
• cerebral findings (mental disturbances, neurological
signs, convulsions)
• hemolytic anemia
• hyperpyrexia
• dysenteric or cholera-like stools
• dark urine
• anuria
Malaria
• P. vivax & P. ovale
– rarely compromise the function of vital organs
– mortality is rare and if it does occur is from splenic
rupture
• P. malariae
– often no acute symptoms
– low level paristemia may persist for decades
– is the most common cause of transfusion malaria
Malaria
• Signs & Symptoms
– typical malarial attacks show sequentially over 4-6
hours
– shaking chills (the cold stage)
– fever to 410 or higher (the hot stage)
– marked diaphoresis (the sweating stage)
Malaria
• Associated symptoms may include:
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–
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fatigue, headache & dizziness
GI symptoms
myalgia, arthralgia & backache
dry cough
Splenomegaly usually appears when acute symptoms
have continued for 4 days or more
– Anemia and jaundice are common manifestations
Malaria
• P. falciparum
– causes the most severe disease and can be fatal if
untreated
– can cause a rapidly fulminating disease characterized
by persistent high fever and orthostatic hypotension
– infection can lead to capillary obstruction and death if
treatment is not prompt
Malaria
• Disease Cycle
– infected female anopheles mosquito bites person
– releases parasites into bloodstream
– parasite enters RBC and multiplies causing the RBC to
burst
– billions of RBC burst at the same time liberating
parasites
– massive discharge causes high fever / shivering
– temperature falls until new batch of parasites evolve
– signs and symptoms start again
Atovaquone/Proguanil
Primaquine
Chloroquine
Doxycycline
Mefloquine
Primaquine
Malaria (Cycle)
• S & S with the cycle
– either from onset or with progression of the disease, the
attacks may show:
• an every other day (tertian) periodicity such as in
falciparum, ovale or vivax
• an every third day (quartan) periodicity in malariae
• After the primary episode, recurrences are common with
each separated by a latent period
Malaria
• Management
– all species except chloroquine resistant P. falciparum
• Chloroquine often combined with primaquine for P.
vivax & P. ovale
• for severe attacks - parental quinine dihydrochloride
– for chloroquine resistant P. Falciparum – quinine plus
one other – doxycycline, clindamycin or others as listed
in table
Malaria
• Prophylaxis
– when out of doors between dusk and dawn use
protective clothing,insect repellant which contains
DEET
– screens should cover bedroom doors and windows
– mosquito nets are a must
– aerosols should be sprayed indoors, preferably with the
doors and windows closed, in the early evening
– burning mosquito mats and coils is a fairly effective
means of keeping mosquitoes at bay during the night
Prophylaxis
• Preventive Drugs
– Chloroqine sensitive:
• Chloroquine - 500mg/week while in area starting 1
week before and continue for 4 week after departing
– Chloroquine resistant:
• Malarone – one tab daily starting the day before
entering the area and continue for 7 days after
• Mefloquine – 250mg tab once a week starting 3
weeks before and continue for 4 weeks after
• Doxycycline – 100mg/daily start 2 days before and
continue with for 4 weeks after
Prophylaxis
• Other points to remember
– compliance with medication regime is of utmost
importance for maximum effectiveness
– symptoms can appear up to six months after leaving a
malaria area
– consult as soon as the following symptoms appear:
fever, rigors, headache, sweating abdominal pain,
diarrhea, loss of appetite, nausea, slight jaundice, cough
and enlarged liver and spleen
• www.who.int/ith/
Malaria
• Case reporting of malaria
– all cases of malaria occurring in CF members, military
members of other forces, dependants or other civilians
who receive their medical care from the CF are to be
reported IAW Current CF Regulations and Orders.
Outline
• Describe the epidemiology, signs and symptoms,
diagnosis, treatment and preventive measure for:
–
–
–
–
–
Amoebiasis
Giardiasis
Trichomoniasis
Toxoplasmosis
Pneumocystis carini
Amebiasis (Dysentery)
• Epidemiology
– is infection of the large colon, liver and other tissues
caused by the protozoan parasite Entamoeba histolytica
– infection results from ingestion of mature cysts found
on fecally contaminated food or water or through
person to person
– humans are the only established host and are
universally susceptible
Amebiasis
• S & S Non-invasive infection (up to 99%)
–
–
–
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asymptomatic (90%)
mild diarrhea
abdominal discomfort
even though asymptomatic can still pass infective cysts
in stool
Amebiasis
• S & S Intestinal infection
– intestinal symptoms can range from mild to moderate
(nondysenteric) to severe colitis (dysenteric colitis)
– abdominal pain & tenderness
– fatigue and wt loss
– flatulence, rectal pain, diarrhea / bloody stools
– fever uncommon initially but as infection increases so
does occurrence of fever
– prostration and systemic toxicity which can lead to
death
Amebiasis
• S & S Extraintestinal infection
– fever (often very high)
– pain (continuous, stabbing, or pleuritic and often very
severe)
– systemic toxicity
– enlarged and tender liver (Amebic Liver Abscess)
– nausea & vomiting
– diarrhea 50%
– hematuria, dysuria, urinary frequency & urgency
Amebiasis
• Diagnosis (laboratory)
– stool for ova & parasites
– diarrheal stool should be examined immediately for
trophozoites and cysts in ordinary stool
• repeated as necessary
– serologic test
• indirect hemaglutination (IHA), positive in 85% of
colitis patients with extraintestinal disease
• should be done in patients with idiopathic
inflammatory bowel disease to rule out amebiasis
Amebiasis
• Treatment
– Asymptomatic intestinal infection
• Iodoquinol
– Mild to Moderate intestinal
• Metronidazole (flagyl) plus iodoquinol
– Severe Intestinal
• Metronidazole (for trophozoites) plus iodoquinol
(luminal agent for protozoan).
• Parental administration may be required
Amebiasis
• Treatment cont’d
– Extraintestinal
• Metronidazole plus iodoquinol
• if hepatic abscess present add Chloroquine
– General Considerations
• fluid, electrolyte and nutritional balance
• pain control
Amebiasis
• Prevention
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avoid water or food that might be contaminated
sanitary disposal of feces
proper handwashing especially in food handlers
proper water treatment – hyperchlorination/iodine
treatment
– proper food storage – not allowing fly contamination
– good personal hygiene
Giardiasis
• Epidemiology
– small intestinal infection caused by a flagellated
protozoan parasite - giardia lamblia
– results from ingestion of trophozites which rapidly turn
into environmentally resistant cysts which in turn are
passed in stool
• Transmission
– cysts are transmitted as a result of fecal contamination
of water or food, by person to person or by anal-oral
sexual contact
Giardiasis
• Signs & symptoms
– may be asymptomatic (25 – 50%) or cause clinical
manifestations from intermittent flatulence to chronic
malabsorption
– acute or chronic diarrhea, mild to severe with bulky,
greasy, frothy, malodorous stools which are free of
blood and pus
Giardiasis
• Signs & symptoms
– upper abdominal discomfort, cramps, distension,
excessive flatulence and weakness are typical
– weight loss (from malabsorption), nausea
– lactose intolerance
Giardiasis
• Diagnosis (laboratory)
– stool for ova and parasite, repeated x 3 if necessary
– cysts are seen in fixed or fresh stools and occasionally,
trophozoites are found in fresh severe diarrhea
– fluorescent antibody and ELISA tests of fecal
specimens are available
Giardiasis
• Treatment
– metronidazole (Flagyl)
– Alternative drugs
• furazolidone
• paromomycin (humatin)
Giardiasis
• Prevention
– education of families, personnel working in daycares,
foodhandlers etc with regards to good hand washing
and personal hygiene
– proper removal of human and animal feces
– proper water treatment (soil filtration has been shown
to remove cysts) with chlorine and iodine based
disinfectant.
Trichomoniasis
• Epidemiology & Etiology
– flagellated protozoan parasite found in men & women
at genitourinary site
– makes up 10- 25% of vaginal infection
– often coexists with gonorrhea (40%)
– highest incidence is in women age 16 to 35
– Sexually transmitted disease
– Incubation period is 4-20 days, (average 7 days)
Trichomoniasis
• Signs & Symptoms in Females
– symptoms typically begin or worsen at time of
menstrual period
– copious, greenish-yellowish and frothy vaginal
discharge with foul odor
– irritation of vulva, perineum and thighs
– dysuria and suprapubic pain, dyspareunia
– in severe cases vaginal walls and surface of cervix may
show punctate, red strawberry spots
Trichomoniasis
• Signs & Symptoms Male
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infects urethra, prostate and seminal vesicles
most are asymptomatic
symptomatic (20%)
may have transient, white, frothy or purulent urethral
discharge
– dysuria
Trichomoniasis
• Diagnosis
– detection of motile protozoans in vaginal or urethral
secretions through microscopic examination or by
culture
• For both genders a full STD workup should be done
Trichomoniasis
• Treatment
– metronidazole
• the single dose is effective in women but has a
higher failure rate in men
– all partners must be treated
– if clinical or microbiological resistance to drug then
high dose IV or topical administration
Toxoplasmosis
• Epidemiology
– infection with the protozoan toxoplasma gondii which
is found worldwide in humans and in many species of
animals and birds
– cats are the definitive host as sexual reproduction of T.
gondii occurs only in their intestinal tract
– the resultant oocysts are passed in feces and can remain
infectious for up to one year in moist soil
Toxoplasmosis
• Human infection results from:
– ingestion of cysts from raw or undercooked meat, or
contaminated food and water
– careless handling of cat litter
– from soil by soil-eating children
– transplacental transmission
– from direct innoculation of trophozoites as in blood
transfusion
Toxoplasmosis
• Four types:
– Primary
• in the immunocompetent patient
– Reactivated
• in the immunocompromised patient
– Congential
– Ocular (Retinochoroditis)
Toxoplasmosis
• Systems affected
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nervous
cardiovascular / pulmonary
GI
skin / exocrine
eyes
Toxoplasmosis
• Signs & Symptoms
• Primary in immunocompetent patients
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over 80% of primary infections are asymptomatic
may resemble infectious mononucleosis
febrile multisystemic complaints
non tender lymphadenopathy of the head and neck
nodes is the most common symptom
– could have one or multiples of malaise, myalgia,
arthralgia, headache and sore throat
Toxoplasmosis
• Reactivated in the immunocompromised
– occurs in 30 to 50% of AIDs patients and can occur in
those with cancer or patients who are receiving
immunosuppresive drugs
– can develop life-threatening encephalitis or
meningioencephalitis
– may present in lungs and eyes and in rare cases in GI
tract, heart, skin and liver
Toxoplasmosis
• Congenital Toxoplasmosis
– congenital transmission occurs as a result of infection
in a nonimmune woman during pregnancy
– up to 1% of pregnancies
– severe infections can result in abortions or stillbirths
– most dangerous in the early pregnancy
– less than 15% however show severe brain or eye
damage at birth, however of all the normal appearing
newborns more than 85% will develop symptoms as an
adult
Toxoplasmosis
• Ocular/Retinochoroiditis
– develops gradually weeks to years after congentital
infection
– focal necrotizing retinitis (yellow or white patches with
blurred margins)
– visual defects include blurring and central defects
– pain and photophobia
– may result in glaucoma and blindness
Toxoplasmosis
• Diagnosis
– skin test
– antibody levels
– amniocentesis at 20-24 wks in suspected congenital
disease
– cysts or trophozoites may be found in blood
– finding tachyzoites confirms acute infection
Toxoplasmosis
• Treatment (Acute)
– in immunocompetent hosts asymptomatic infection not
treated unless findings are severe or persistent
– symptomatic - treated until all signs of the illness have
subsided (3-4 weeks)
– immunocompromised - treated 4 to 6 weeks post
symptoms
Toxoplasmosis
• Treatment (Acute)
– pyrimethamine (daraprim) plus sulfadiazine
(microsulfon)
– Folinic acid may be given to counteract the suppression
of bone marrow by pyrimethamine
– ocular patients should receive corticosteroids
– Spiramycin for pregnant women
Toxoplasmosis
• Prevention
– freezing of meat to –200 C for 2 days or heating meat to
600 C for 4 minutes kills cysts in tissue
– wearing of gloves or using scoop when dealing with cat
litter or gardening
– cats should be kept as indoor pets only and fed dry,
canned or cooked food only
– ensure thorough washing of hands, utensils and kitchen
surfaces etc. after exposure to raw meat
Pneumocystis carinii
• Epidemiology & Etiology
– now considered a fungal disease rather than a protozoan
one
– pneumonia arising in immunosuppressed persons
caused by Pneumocystis carinii (PCP)
– one of the most common opportunistic infections
occurring in patients with HIV infections
– can cause organ involvement & disseminated disease as
well as pneumonia
Pneumocystis carinii
• Signs & Symptoms
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abrupt onset
fever
tachypnea, shortness of breath
usually non productive cough
radiographic findings
adult patients may present with spontaneous
pnuemothorax
Pneumocystis carinii
• Diagnosis (Laboratory)
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–
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serum LDH
positive lung washings
arterial blood gas shows hypoxia
CD4 cell count generally below 200 in HIV infected
patients with PCP
– Imaging - chest x-ray shows diffuse bilateral perihilar
infiltrates
– Histological demonstration of the organism in sputum
or in bronchoscopy
Pneumocystis carinii
• Treatment
– trimethoprim-sulfamethoxazole (bactrim, septra)
– adjunctive corticosteroid (prednisone or methyl
prednisolone) therapy begun within 72 hrs of Dx
decreases mortality in AIDS patient (adults & children)
• Prevention
– no true means of prevention however prophylaxis is
recommended in the immunocompromised
Outline
• Describe the epidemiology, signs and symptoms,
diagnosis, treatment and preventive measures for the
following helminthic diseases
– nematodes
– cestodes
– trematodes
Helminthic Disease
• Nematodes (Roundworms)
– are nonsegmented cylindrical or spindle shaped worms
ranging from 1mm to almost 1 m in length
– unlike other helminthics, these have have a complete
digestive system, including a mouth,body length
intestinal tract and an anus
– two kinds: intestinal and tissue
– most have separate, anatomically distinctive sexes
– mode of transmission depends on the species
Nematodes
• Intestinal
– Ascariasis
(Roundworm Disease)
– Trichuriasis
(Whipworm Disease)
– Hookworm Disease
– Enterbiasis (Pinworm
Disease
– Strongyloidiasis
(Threadworm Disease)
• Tissue
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–
–
–
Trichinosis
Loiasis
Dracunculiasis
Onchocerciasis (River
Blindness)
– Visceral Larval
Migrans
– Filariaisis
Ascariasis
• Epidemiology
– caused by ascaris lumbricoles
– most common of the intestinal helminths
– transmitted by ingestion of soil containing the
organism’s eggs or in fecally contaminated food and
drink
– humans are the sole host
– larvae grow in the intestine, causing abdominal
symptoms
– roundworms may pass to the blood and lungs
Ascariasis
• S&S
– larvae in the lung cause capillary and alveolar damage
– low grade fever, non productive cough, blood tinged
sputum, wheezing, dyspnea and sub-sternal pain
– adult worms usually produce little, if any, GI symptoms
but the passage of a worm in feces may bring the
patient in
– heavy infections may produce ulcer like symptoms or
intestinal obstruction
Ascariasis
• Diagnosis
– microscopic detection of eggs in stools and
occasionally adult worms in stool or vomitus
– during pulmonary phase eosinophils may be elevated as
much as 30 to 50% and remain high for about a month
– larvae may be found in sputum
Ascariasis
• Treatment
–
–
–
Albendazole
Mebendaxole (Vermox)
Pyrantel Pamoate
stools must be checked at 2 weeks and patients
retreated until all evidence of infestation is gone
Trichuriasis (Whipworm Disease)
• Epidemiology
– a nematode infection of the large intestine, usually
asymptomatic, caused by Trichuris trichiura
– passed through ingestion of eggs from contaminated
food or after incubation of larvae in 10 to 14 days by
fecal oral route
– adult worms embed their heads into the mucosal lining
of the cecum or colon
Trichuriasis (Whipworm Disease)
• S&S
– light infections often asymptomatic
– heavy infections may have abdominal cramps, diarrhea,
distention, flatulence, nausea and vomiting and weight
loss
– can lead to rectal prolapse
Trichuriasis (Whipworm Disease)
• Diagnosis
– characteristic lemon shaped eggs in stool
– eosinophilia is common in all but light infections
– severe iron deficiency in heavy infection
• Treatment
– asymptomatic infections do not require treatment
– for heavier infections can give Albendazole or
Mebendazole
Hookworm (Ancylostomiasis)
• Epidemiology
– caused by Ancylostoma duodenale and Necator
americanus. Common in 25% of population
– human infection occurs when larvae penetrate the skin,
usually in the foot, and pass via lymphatics and
bloodstream to the lungs where they enter the alveoli
– they are then carried by ciliary action up the bronchus,
trachea and mouth where they are swallowed and attach
to the mucosa of the upper small bowel
– worms suck blood at their attachment sites (anemia)
Hookworm (Ancylostomiasis)
• S&S
– ground itch is a characteristic pruritic erythematous
dermatitis, either maculopapular or vesicular
– in pulmonary stage there may be dry cough, wheezing,
blood tinged sputum and low grade fever
– in light infestations GI symptoms my be absent with
undetectable blood loss
Hookworm (Ancylostomiasis)
• S&S
– in heavy infections wide range from anorexia, diarrhea,
abdominal discomfort and palpitations
– can lead to iron deficiency and hypochromic,
microcytic anemia with fatigue, pallor, exertional
dyspnea, deformed nails and heart failure
Hookworm (Ancylostomiasis)
• Diagnosis
– thin shelled oval eggs and occult blood in stool
– low hemoglobin, serum iron and serum ferritin
– eosinophilia and leuckocytosis are present in the pulmonary stage
but not in chronic intestinal phase
• Treatment
- Albendazole
–
–
–
–
Mebendazole
Pyrantel Pamoate
Levamisole
re-treatment may be necessary at 2 week intervals
Enterobiasis (pinworms)
• Description
– intestinal infection with enterobius vermicularis
– transmission is person to person, indirect or auto
reinfection
– most common nematode infection and is most often
seen in children
– humans are the only host
– multiple infections in families
Enterobiasis (pinworms)
• S&S
–
–
–
–
–
nocturnal perianal itching (characteristic symptom)
perineal itching/vulvovaginitis
enuresis
abdominal pain
insomnia
Enterobiasis (pinworms)
• Diagnosis
– transparent tape test
– flashlight to perianal region at night for direct
observation
– digital rectal examination with saline slide preparation
of stool on gloved finger
• Treatment
– Mebendazole (vermox)
– Pyrantel pamoate
Enterobiasis (pinworms)
• Prevention / Avoidance
– careful hand washing, keep nail short and clean
– wash anus and genitals at least once a day, preferably in
the shower
– don’t scratch anus or put fingers near nose or mouth
– clean bedding, underclothing and night clothes daily
preferably after bathing
– vacuum infected house daily for several days after
treatment
Strongyloidiasis (Thread Worm)
• Epidemiology
– relatively uncommon intestinal nematode
– benign disease in normal individuals but can be fatal in
immunocompromised patient
– transmitted by direct skin penetration of larvae found in
fecally contaminated soil
– after entering the skin they enter the venous system and
travel to the lungs, ascend the trachea to the epiglottis
and then descend into the digestive tract
Strongyloidiasis (Thread Worm)
• S&S
– transient dermatitis
– cough, rales, sore throat, dyspnea, wheezing and
hemoptysis
– abdominal symptoms:
• diarrhea (may alternate with constipation)
• abdominal pain
• flatulence
• anorexia
Strongyloidiasis (Thread Worm)
• Diagnosis
– finding eggs and larvae in stool
• Treatment
- Ivermectin
– Thiabendazole (mebendazole)
– treatment should continue until all traces of parasite are
gone
Nematodes
• Intestinal
– Ascariasis
(Roundworm Disease)
– Trichuriasis
(Whipworm Disease)
– Hookworm Disease
– Enterbiasis (Pinworm
Disease
– Strongyloidiasis
(Threadworm Disease)
• Tissue
–
–
–
–
Trichinosis
Loiasis
Dracunculiasis
Onchocerciasis (River
Blindness)
– Visceral Larval
Migrans
– Filariaisis
Trichinosis (Trichinellosis)
• Epidemiology
– caused by Trichinella Spiralis, an intestinal nematode
that encysts in the tissues of human and porcine hosts
– transmitted by eating undercook pork
– in the epithelium of small intestine larvae develop into
adults
– female worms then produce larvae which penetrate
lymphatics or venules into the bloodstream then
become encapsulated in skeletal muscle
Trichinosis (Trichinellosis)
• S&S
– first week - diarrhea, cramps and nausea
– second week to 2 months – sudden appearance of
muscle pain, edema of upper eyelids, fever
photophobia, conjunctivitis and myalgia are
characteristic signs
– may be followed by subconjunctival, subungual and
retinal hemorrhages
– muscles of respiration, speech, mastication and
swallowing may be affected
Trichinosis (Trichinellosis)
• Diagnosis
– Eosinophilia and elevated serum muscle enzymes
– Positive serologic test, muscle biopsy
• Treatment
– Intestinal phase
• Abendazole / Mebendazole
– Muscle invasion phase
• severe infections require hospitalization and high
doses of corticosteroids
Loiasis
• Epidemiology
– chronic filarial diseased caused by Loa loa
– widely distributed in the African Rain Forest
– adult worms can live in subcutaneous tissue for up to
12 years
– transmission is by the deer fly.
– the larvae crawl under the skin and can enter the eye
where adult worms are visible in the conjunctival space
around the iris
Loiasis
• S&S
– characteristic tracks and visible worms under the skin
– transient swellings several centimeters in diameter
anywhere on the body (Calabar swellings)
– these swellings are non pitting and nonerythematous
and are at times associated with low grade fever, local
pain and pruritis
– migration of worms across the eyes may cause pain
and intense conjuctivitis
Loiasis
• Diagnosis
– detection of microfilariae in blood specimens taking
during daytime (between 10 AM to 4 PM)
• Treatment
- Diethylcarbamazine (DEC)
– Albendazole
Dracunculiasis
• Epidemiology
– infection of the subcutaneous and deeper tissues by the
large nematode Dracunculus medinensis
– only occurs in humans and is a major source of
disability in affected areas
– found in Saudi Arabia, Iran, Central and West Africa,
Yemen and the Indian subcontinent
– transmission is by drinking water containing the
intermediate hosts copepods, water fleas, in which the
larvae live
Dracunculiasis
• Epidemiology
– the larvae are liberated in the stomach and cross the
duodenal wall into the viscera and become adults
– after mating the male worm dies and the pregnant
female (60-100 cm x 1.7 – 2.0 mm) moves to the
surface of the body, where its head reaches the
dermis and provokes a blister, which when in
contact with water ruptures and the uterus discharges
great numbers of larvae
– some worms retract and re-emerge many times and
others eventually disintegrate
Dracunculiasis
• S&S
– infection may be at several sites
– normally asymptomatic during the 9 to 14 month
incubation period except in the last 1-2 weeks when the
worm reaches and becomes palpable in the skin
– a blister will develop around the worms anterior end
– several hours before the head appears at the surface,
local erythema, burning, pruritis and tenderness
develop
Dracunculiasis
• S&S cont’d
– systemic allergic reactions such as pruritis, fever nausea
and vomiting,dyspnea, periorbital edema and urticaria
may occur 24 hours in advance of head emergence
– after rupture of the ulceration, tissues may become
indurated, reddened and tender
– secondary infections such as tetanus are common
– ankle and knee joints infections often result in
deformity
Dracunculiasis
• Diagnosis
– if not visible on or just below the surface of the skin
then larvae may be seen in smears from discharging
skin sinuses
– immersion of area in cold water will stimulate
expulsion of larvae
– Eosinophlia is normally present
Dracunculiasis
• Treatment
–
–
–
–
tetanus immunization
manual Extraction
surgical Removal
following drugs have an anti-inflammatory effect but
do not kill the larvae:
• Metronidazole
• Mebendazole
Onchocerciasis (River Blindness)
• Epidemiology
– caused by Onchocerca volvulus
– found in Guatemala, southern Mexico, Venezuela,
Amazon area and sub Saharan Africa
– transmitted to humans through black fly bites
– a chronic non-fatal filarial disease with fibrous nodules
which contain the worms
– adult worms also found in deep seated bundles lying
beside the periosteum of bones or near joints
Onchocerciasis (River Blindness)
• Epidemiology cont’d
– female worm discharges microfilariae that migrate
through the skin often causing an intense pruritic rash,
chronic dermatitis, altered pigmentation, edema and
atrophy of the skin
– microfilariae often reach the eye, where their
invasion and subsequent death causes visual
disturbances and blindness
Onchocerciasis (River Blindness)
• S&S
–
–
–
–
pruritic rash
subcutaneous nodules
ocular lesions
pigment changes (usually lower limbs) – often called
leopard skin
– loss of skin elasticity and lymphadenitis
– in heavy infections larvae may be seen in urine, blood,
tears and sputum
Onchocerciasis (River Blindness)
• Diagnosis
– Microscopic examination of superficial skin biopsies
– Evidence of larvae in body fluids
– Slit lamp examination
• Treatment
– Ivermectin
– surgery
Visceral Larval Migrans
(Toxocariasis)
• Epidemiology
– due to toxocara canis (dogs) and T. cati (cats)
– a chronic and usually mild disease predominantly in
young children but on the increase in adults
– eggs are shed in feces of infected dogs and cats
– direct or indirect transmission from contaminated soil,
food and meat
– most common in female dogs and puppies
Visceral Larval Migrans
(Toxocariasis)
• S&S
– migrating larvae may induce fever, cough,wheezing,
enlarged liver and spleen
– most cases are in children, who present with visual
impairment in one eye, leukocoria, squint and loss of
red reflex.
• Diagnosis
– elevated WBC and eosinophilia
– microscopic evidence of larvae
Visceral Larval Migrans
(Toxocariasis)
• Treatment
–
–
–
–
primarily supportive
Albendazole/ Mebendazole
symptoms may persist for months
usually good outcome but permanent neurological
deficits can occur
Filariasis (Elephantiasis)
• Epidemiology
– the most frequent cause of this is Wuchereria
bancrofti, Brugia malayi and Brugia Timori
– these filarial worms block the flow of lymph, causing
edematous arms, legs and scrotum
– transmission is through the bite of the Anopheles,
Aedes and Culex mosquitoes
– humans are the only hosts for Bancrofti and Timori but
monkeys and cats may harbour Malayi
Filariasis (Elephantiasis)
• S&S
– incubation period can be 8-16 months
– many infections are asymptomatic
– in acute disease:
• fever with or without inflammation of lymphatic
nodes which occur at regular intervals and lasts for
several days
• in men, as disease progresses may have orchitis and
epididymitis
Filariasis (Elephantiasis)
• S&S cont’d
– in travellers allergic like findings are common and
include:
• hives, rashes and eosinophlia
– in chronic disease:
• obstruction of lymphatic flow including hydrocele,
scrotal lymphedema, lymphatic varices
• elephantiasis of extremities, genitals and breasts
Filariasis (Elephantiasis)
• Diagnosis
– microscopic examination of blood or hydrocele fluid
reveals microfilariae
– there is an antigen test for Bancrofti
– Bancrofti are found mostly in nocturnal specimens
(10PM – 2AM)
Filariasis (Elephantiasis)
• Treatment
– Diethylcarbamazine, albendazole or invermectin
– Mass treatment involving 80 countries continues to be
underway to reduce disease and to achieve total
eradication by 2020
– albendazole and invermectin are used in Africa and
albendazole and diethylcarbamazine are used in all
other locations
Nematodes (Roundworms)
• Generalized Precautions and Prevention Methods
– adequate sanitation and proper disposal of feces
– proper water treatment
– uncooked or unwashed vegetables should be avoided in
areas where human feces is used as fertilizer
– proper cooking of fish and other marine life
– proper handwashing and ensuring good health and
hygiene in foodhandlers
– proper follow-up and education to ensure infection is
eradicated and/or prevented
Nematodes (Roundworms)
• Generalized Precautions and Prevention Methods
– ensuring pets are properly cared for, immunized and
dewormed and not fed raw or uncooked food
– children’s sandboxes kept covered
– ensure food is properly stored e.g. freezing, not left
open
– fly/insect control
Cestodes (tapeworms)
• Description
– adult cestodes are long, flat, segmented worms that lack
a digestive tract
• Three parts to a tapeworm
– Scolex (head) - functions as a holdfast organ
– Neck - unsegmented region of highly regenerative
capacity
– Segments(proglottides) - distal segments are gravid and
contain eggs
Cestodes (tapeworms)
• Transmission
– ingestion of meat, pork or fish that is improperly
cooked or vegetables that have been fertilized with
human or animal feces
– autoinfection - hand to mouth
– human to human
– contaminated water
– ingestion of intermediate hosts (fleas, beetles or
cockroaches
Cestodes (tapeworms)
• Six tapeworms infect humans
–
–
–
–
–
–
Beef tapeworm:
Pork tapeworm:
Fish tapeworm:
Dwarf tapeworm:
Rodent tapeworm:
Dog tapeworm:
Up to 25m in length
7m
10m
25-40 mm
20-60 cm
10-70 cm
Cestodes (tapeworms)
• S&S
– large tapeworm infections are generally asymptomatic,
but may have vague gastrointestinal symptoms
– nausea, diarrhea, abdominal pain, fatigue, hunger
dizziness
– infection by a beef or pork tapeworm is often
discovered by the patient finding segments in stool,
clothing or bedding
Cestodes (tapeworms)
• Diagnosis
– stool evaluation of O & P
– microscopic evaluation of proglottid collected in water
or saline
– cellulose tape
– serologic testing
– imaging, Ct and MRI
Cestodes (tapeworms)
• Treatment:
– Praziquantel
– niclosamide
• Prevention
–
–
–
–
–
proper cooking of beef, pork, fish
proper freezing of meat or fish
fecal-oral precautions with good hand washing
treatment of infected dogs, and preventing fleas
education
Trematodes (Fluke)
• Trematodes
– parasitic flat worm
– depending on the species, infest various organs of the
host (intestinal veins, urinary bladder, liver or lung)
– two kinds:
• hermaphrodite - ingested
• sexual flukes – direct penetration though skin
– all use freshwater snails as intermediate host
Trematodes (Fluke)
• Types and Causes of Trematodes:
–
–
–
–
–
Schistosomiasis - direct skin penetration or ingestion
Fasciolopsiasis – eating uncooked water plants
Clonorchiasis – eating raw freshwater fish
Fascioliasis – raw plants (watercress)
Paragonimiasis – eating raw crab meat
Trematodes (Fluke)
• Schistosmiasis
– most important Trematode infection
– snails are intermediate hosts
– two kinds:
• New World – s. mansoni – intestinal
– damage to the intestinal wall is caused by host’s
inflammatory response to deposited eggs
– eggs secrete proteolytic enzymes that further
damage tissue
Trematodes (Fluke)
• Schistosmiasis
• Old world – S. hematobium – urinary
– primary sites of infection are the veins of the
urinary bladder
– organism’s eggs can induce fibrosis, granulomas
and hematuria
Schistosmiasis
• S&S
• Acute phase
– Intestinal
• fever, urticaria, diarrhea (sometimes bloody),
malaise, myalgia, weight loss, headache, dry cough,
liver and spleen enlargement
– Urinary
• frequency, dysuria, terminal hematuria and
proteinuria
Schistosmiasis
• Chronic Intestinal phase
– this stage begins 6 months to several years after
infection
– abdominal pain, irregular bowel movements bloody
stool, hepato/splenomegaly, hematuria, urethral/bladder
pain
– with subsequent slow progression the following may
appear: anorexia, weight loss, polypoid intestinal
tumors, and features of portal and pulmonary
hypertension
Schistosmiasis
• Chronic Urinary
– bladder polyp formation, cystitis, chronic salmonella
infection
– pyelitis, pyelonephritis, urolithiasis, hydronephrosis
– bladder cancer has been associated with vesicular
schistosomiasis
Trematodes (Fluke)
• Diagnosis
– stool examination
– serologic tests (highly sensitive)
– MRI or ultrasonography
• may detect periportal fibrosis & calcified eggs in the
liver, the intestinal wall, or the bladder & ureter
– abdominal x-ray
Trematodes (Fluke)
• Treatment
– praziquantel
– oxamniquine
• Prevention
– proper disposal of feces and urine
– control of snail population through use of molluscides
– scrupulously avoiding contact with contaminated water
prevents infection