protozoa infections Flashcards
Humans can become infected by toxo by any of several routes:
4
- Eating undercooked meat of animals harboring tissue cysts
- Consuming food or water contaminated with cat feces
- Blood transfusion, organ transplantation, needlestick
- Transplacentally from mother to fetus (aka congenital toxo)
________ localize to neural or muscular tissue
Tachyzoites
oocysts
capsule
congenital tox
1st and 3rd trimester. with those from the 1st more CNS related effects
primary infection for toxo is
a positive IgM
Reactivation: Cannot use presence or absence of IgM to diagnose reactivation
yep
tx with toxo:
primary vs reactivation
Primary Infection Usually self-limited, no treatment needed If eye involvement, treat with Pyremethamine + sulfadiazine OR Pyremethamine + clindamycin AND Leucovorin (folinic acid)
Reactivation: the same as primary with eye involvement, but with higher doses
prevention of toxo in HIV
need to be on trimethoprim sulfamethoxazole (Bactrim) until CD4 count > 100
Protozoa that are flagellates
Transmitted by bite of the sandfly which usually bites at night
leishmaniasis
three forms of leishmaniasis
- cutaneous
- mucocutaneous
- visceral (kalazar)
leishmaniasis:
Lesions can be single or multiple; appear 6 weeks after inoculation, starts as a papule, ulcerates over time
Classic appearance: “heaped up” borders, non-tender; on exposed skin
May heal spontaneously (90% of cases)
Cutaneous:
leishmaniasis :
Initial symptoms similar to cutaneous and resolve
Months to years later, 1-5% of patients develop ulcers on oral or nasal mucousa
Progression of the infection is slow, but unless treatment is given, the entire nasal mucosa and the hard and soft palates can be destroyed.
Death usually occurs from secondary infection
Mucocutaneous (Only New World)
leishmaniasis :
Amastigotes enter macrophages; disseminate to liver, spleen, and bone marrow
Mostly seen in children and immunosupressed adults from Bangladesh, India, Sudan and Brazil
Onset can be insidious or acute; weeks to months after initial infection
Symptoms: Fever, weight loss, cachexia, diarrhea, malabsorption
Physical Exam: Organomegaly; Earth gray skin color, nodular skin lesions, oral and nasal ulcers
Labs: Pancytopenia, Hypergammaglobulinemia
visceral
Cellular immune responses (Th1) are \_\_\_\_\_\_\_\_ Humoral responses(Th2) \_\_\_\_\_\_\_\_\_\_\_
AIDS patients and
Immunocompromised hosts
Cellular immune responses (Th1) are protective
Humoral responses(Th2) protective
AIDS patients frequently develop severe Leishmania infections
Immunocompromised hosts tend to relapse
diagnosis of cutaneous form of leishmans
Smear, scrape or touch prep of skin lesion stained with giemsa
