PAS 604 Medically Important Parasites & Fungi

non-mutual relationship between species

where one species (the parasite)

benefits and or survives

at the expense of the other (the host)

What is a parasite?

- Stool ova and parasite (O&P)

- Antigen serology

- Molecular/genetic identification

What testing is done for parasites?

- Wet mount

- Trichrome stain

What is looked at in a Stool ova and parasite (O&P) test>

- PCR

- NAAT

What are examples of molecular/genetic identification testing for parasites?

Amoebiasis

What disease does Entamoeba histolytica (ameba) cause?

- asymptomatic intestinal colonization

- invasive intestinal colitis (amebic dysentery

- invasive extra-intestinal forms (liver or pleuropulmonary abscesses)

What are the three forms of Amoebiasis?

Human reservoir - chronic carriers

What is the habitat of Entamoeba histolytica (ameba)?

Ingestion from fecal contaminated food, water, hands, or sexual contact

How is Entamoeba histolytica (ameba) transmitted?

stool O&P for cysts, serologic (EIA, PCR, GI pathogen panel)

How is Entamoeba histolytica (ameba) diagnosed?

Entaomeba histolytica

Giardiasis

What disease does Giardia Lamblia (flagellate) cause?

Incubation 1-14 days, sudden onset watery diarrhea, GI symptoms - abd pain/N/V/D

What are the symptoms of giardiasis?

Giardiasis

What is the most common diagnosed parasitic intestinal disease in the US?

- freshwater streams, daycare outbreaks

What is the habitat of Giardia Lamblia?

- Cyst ingestion from fecal contaminated food or water

- Animal reservoirs (cats, dogs, deer, beavers), person - person

How is Giardia Lamblia transmitted?

stool O&P; serologic Giardia antigen by ELISA or DFA, PCR available to speciate subtypes

How is Giardia Lamblia diagnosed?

Cryptosporidiosis

What disease does Cryptosporidium parvum (sporozoan) cause?

- asymptomatic/mild in immunocompetent host

- watery diarrhea m/c symptom

- severe GI symptoms immunocompromised

- infect intestinal epithelium - wt loss/abd pain, N/V/fever

What are the symptoms of Cryptosporidiosis?

- cyst ingestion from fecal contaminated food or water

What is the habitat of Cryptosporidium parvum?

- domestic or farm animals, person-person at the POOL

How is Cryptosporidium parvum transmitted?

modified Acidfast stain (Kinyon), serologic antigen detection by ELISA, PCR testing available

How is Cryptosporidium parvum diagnosed?

Cryposporidium

What is the leading cause recreational water related disease outbreaks?

Trichomoniasis

What disease does Trichomonas Vaginalis casue?

- Vaginitis/cervicitis

- purulent d/c, pain, dyspareunia

- urethritis, epididymitis, prostatitis

What are symptoms of Trichomoniasis?

Humans only known host

What is the habitat for Trichomonas Vaginalis?

sexual contact or via birth canal in infants

How is Trichomonas Vaginalis transmitted?

- DNA probe, PCR, NAAT (high sensitivity)

How is Trichomonas Vaginalis diagnosed?

Malaria

What disease does Plasmodium species (falciparum, vivax, ovale, malariae) cause?

- Travel hx important in endemic areas!!!

- Fever/chills, malaise, myalgia's, anemia, splenomegaly - depend on species and patient immune status

What are symptoms of malaria?

infected female anopheles mosquito bite, infected blood contaminated needles, blood transfusions, congenital transmission

What is the habitat of Plasmodium species (falciparum, vivax, ovale, malariae)?

migrate to liver and invade RBCs

How is Plasmodium species (falciparum, vivax, ovale, malariae) transmitted?

- Thin/thick blood smears - detection via Giemsa staining (purple top tube)

- RDT's (rapid diagnostic tests) by serologic antigen detection available but need confirmation by microscopy

How is Plasmodium species (falciparum, vivax, ovale, malariae) diagnosed?

Babesiosis

What disease does Babesia microti cause?

- Most cases asymptomatic

- similar to malaria- fever/chills, myalgia's, fatigue, hepatosplenomegaly

What are the symptoms of Babesiosis?

2 hosts - tick & rodent needed to reproduce - human dead-end host

What is the habitat of Babesia microti?

- bite from infected Ixodes scapularis tick

- blood transfusion

How is Babesia microti transmitted?

Thin/thick blood smears, serologic antibody detection IFA or IgM antibody titers, molecular diagnosis by PCR

How is Babesia microti diagnosed?

Toxoplasmosis

What disease is caused by Toxoplasma gondii?

- Manifest in body fluids, brain, eye and muscles

- Immunocompetent infection asymptomatic or benign, severe in immunocompromised or congenital

What are the symptoms of Toxoplasmosis?

distributed worldwide in vertebrates, definitive host/reservoir common house cat/other felines-

What is the habitat of Toxoplasma gondii?

feces contamination, transplacental transmission, or blood transfusion

How is Toxoplasma gondii transmitted?

- serologic testing IgG /IgM antibodies, new fluorescent stains for direct detection (IFA)

- PCR in blood, CSF, amniotic fluid

How is Toxoplasma gondii diagnosed?

Chagas Disease -American Trypanosomiasis

What disease is caused by Trypanosoma cruzi?

- Found in the Americas, endemic in Latin America, increasing incidence in US

- Acute/chronic infections may be asymptomatic result in cardiac/intestinal complications

What are the symptoms of Chagas Disease -American Trypanosomiasis?

Vector borne from triatomine insects

What is the habitat of Trypanosoma cruzi?

- Vector borne from triatomine insects (kissing bugs) biting human faces, blood or organ transfusion, congenital transmission

How is Trypanosoma cruzi transmitted?

- Acute - Giemsa stained blood smears

- Chronic - serologic detection of T. cruzi (ELISA, IFA) and PCR for congenital cases

How is Trypanosoma cruzi diagnosed?

Chagas Disease -American Trypanosomiasis

- Taeniasis

- Cysticercosis

What disease do Cestodes (flatworms/tapeworms) cause?

- Taenia saginata (beef)

- Taenia solium (pork)

What are the types of cestodes (tapeworms) and where do they come from?

intestinal - asymptomatic or mild GI symptoms w/passage of proglottids (from ingestion of adult form in pork/beef as cysterci) GB complications due to migration of parasite

What are the symptoms of Taeniasis?

(extraintestinal)- T. solium only - infection by larval cysts due to ingestion of eggs from contaminated feces. Burrow into blood, travel into muscle, brain, eye and form cysticerci - cause seizures, HA

What are the symptoms of Cysticercosis?

flatworms, tapeworms

What are cestodes?

roundworms

What are nematodes?

ingestion of infected undercooked meat containing adult tapeworm

How is taeniasis transmited?

ingestion of T. solium eggs from contaminated food/water or fecal-oral route

How is Cystercercosis transmited?

- Stool O & P (proglottids may be seen in stool)

- serologic antibody testing of tissue, blood or muscle biopsy

- PCR testing

- MRI/CT scan of brain for neurocystercercosis

How are cestodes diagnosed?

only T. solium

What causes Cysticercosis?

Both T. solium and T. saginata

What causes Taeniasis?

Taenia solium

What casues Neurocysticercosis?

Diphyllobothriasis

What disease does Diphyllobothrium latum cause?

Diphyllobothrium latum (30 feet)

What is the largest human tapeworm?

- Most infections asymptomatic/long lasting

- Abdominal pain, V/D, weight loss

- Resides in small intestine

What are symptoms of Diphyllobothrium latum?

Vit B12 deficiency, intestinal obstruction, GB disease (proglottids migrate)

What are complications of Diphyllobothrium latum?

freshwater fish

What is the habitat of Diphyllobothrium latum?

ingestion of raw or undercooked freshwater fish

How is Diphyllobothrium latum transmitted?

- Molecular PCR

- Eggs or segments of tapeworm in stool

How is Diphyllobothrium latum diagnosed?

Roundworms, Hookworms, Pinworms, Threadworms

What are nematodes?

hookworms

What are Necatur Americanus, Ancylostoma duodenale?

Itching/rash @ infection site, range from asymptomatic to mild diarrhea/abd pain can progress to anemia (IDA), delayed growth & development

What are the symptoms of hookworm disease?

humans sole host/no person-person

What is the habitat of hookworms?

- contact w/soil contaminated w/human feces through bare feet or ingesting contaminated soil

- larvae forms infective (children at high risk)

- larvae migrate to lungs, coughed up, swallowed to small intestine , attach to wall and suck blood

How are hookworms transmitted?

stool O&P for detection of eggs, earlier detection with ELISA antigen availability

How are hookworms diagnosed?

roundworms

What are Ascaris lumbricoides?

Ascariasis

What disease is caused by Ascaris lumbricoides?

- Intestinal w/abdominal pain - may cause obstruction in small intestine OR

- Pulmonary manifestation as pneumonia

What are the symptoms of Ascariasis?

humans sole host

What is the habitat of Ascaris lumbricoides?

1. Enterobius vermicularis (pinworm)

2. Ascaris lumbricoides (roundworms)

What is the most common type of parasite in humans?

ingestion of eggs in soil contaminated with human feces, they hatch and enter blood circulation and travel to lungs, coughed up and re-enter intestines for maturation

How is Ascaris lumbricoides transmitted?

- stool O&P for detection of eggs

- early detection with ELISA antigen availability

How is Ascaris lumbricoides diagnosed?

Enterobiasis

What disease is caused by Enterobius vermicularis?

- ingestion of eggs fecal oral route with reinfection & family exposure common

How is Enterobius vermicularis transmitted?

humans only host

What is the habitat of Enterobius vermicularis?

- Scotch tape test

- worms visible in stool or perianal area

- Serology not available

How is Enterobius vermicularis diagnosed?

pruritis ani

What are the symptoms of Enterobiasis?

Strongyloides stercoralis

What causes threadworm disease?

Strongyloidiasis

What disease is caused by Strongyloides stercoralis?

- GI - abd pain/diarrhea

- Pulmonary manifestations, lead to septicemia

What are the symptoms of Strongyloidiasis?

soil contaminated by feces via direct skin penetration into bloodstream to lungs, coughed up and swallowed into GI tract

How is Strongyloides stercoralis transmitted?

stool O&P for larval forms - examine stool for adult worms, antibody detection by EIA

How is Strongyloides stercoralis diagnosed?

Humans, cats, dogs as definitive hosts

What is the habitat of Strongyloides stercoralis?

yeast and mold

What are the two forms of fungi?

fungi

_______ are dimorphic

yeast form in one environment mold form in another (due to variances of CO2 and temperature)

What does dimorphic mean?

- superficial mycoses (opportunistic)

- deep mycoses (systemic infections)

What are skin fungal infection types?

true pathogens (can infect healthy & immunocompromised)

What are deep mycoses?

opportunistic pathogens (only infect immunocompromised

What are superficial mycoses?

Candidiasis

What disease is caused by candida species?

albicans, tropicalis, glabrata

What are common Candida species?

- Thrush (mouth), vaginitis (F), balanitis (M)

- can become systemic (need blood cultures)

What are the symptoms of candidiasis?