Parasite (S-T) Flashcards
which causes sarcosystosis?
intracellular coccidian protozoan parasites;
genus Sarcocystis;
which species cause intestinal sarcocystosis?
how is it transmitted?
S. heydorni
S. hominis
S. suihominis
eating undercooked beef or pork
which species cause muscular sarcocystosis?
S. nesbitti
food, water, or soil contaminated with the feces from a reptilian sporocyst-shedding definitive host, likely snakes
which areas is sarcocystosis most reported?
tropics and subtropics, particularly in SE Asia;
recent outbreaks of muscular sarcocystosis in Malaysia
what are the symptoms of sarcocystosis?
most asymptomatic, or mild gastroenteritis, but severe illness has been described;
self-limited in immunocompetent hosts
symptoms: arthralgia, cough, fatigue, fever, headahe, myalgias; less frequent symptoms include diarrhea, nausea, vomiting, lymphadenopathy, rash, wheezing, cardiac involvment (palpitation)
how to dianose sarcocystosis?
oocysts or sporocysts in stool confirmed by light or fluorescence microscopy;
how to treat sarcocystosis?
no proven treatment;
trimethoprim-sulfamethoxazole might act against schizonts in the early phase of muscular sarcocystosis;
glucocorticoids and NSAIDS can improve the symptoms associated with myositis.
what causes scabies?
human itch mite, Sarcoptes scabiei var. hominis
how are scabies transmited?
Direct transmission of conventional scabies occurs after prolonged skin-to-skin contact with a person infested with the mite.
Crusted scabies, by contrast, is more contagious than conventional scabies.
Although <20 mites typically are found on a host with conventional scabies, a person with crusted scabies, formerly called Norwegian scabies, can harbor thousands of mites in just a small area of skin. The large number of mites present in crusted scabies greatly increases the chances that a person with crusted scabies will pass mites to others by both direct and indirect routes of transmission.
what are the symptoms of scabies?
intense itching, especially at night;
papular itchy rash;
how to treat scabies?
permethrine 5% cream;
ivermectin
permethrine - apply from neck down, left on 8-12 hours or overnight; wash off; 2nd application after 1 week
-treat household members and close contacts
ivermectin - 200 ug/kg, repeated after 1-2 weeks; oral ivermecti should not be used in children weight <15kg or in pregnant people
how to treat crusted scabies?
permethrin + ivermectin;
daily full-body application for 7 days;
7 or less doses of oral ivermectin
what causes schistosomiasis (bilharzia and snail fever)?
helminth parasites of the genus Schistosoma;
how do you get schistosomiasis?
larval cercariae, found in contaminated bodies of freshwater, penetrate the skin
what is the intermediate host of schistosomiasis?
snail
where are schistosomiasis cases found?
85% Africa; prevalence rates can exceed 50% in local population
which schistosomiasis species are found in Africa?
Schistosoma mansoni
S. haematobium
what schistosoma species found in Brazil, Suriname and Venezuela?
S. mansoni
what schistosoma species found in the middle east?
S. haematobium
which schistosoma specis found in the Caribbean (Guadeloupe, Martinique, Saitn Lucia, Dominican Republic)?
S. mansoni
which schistosoma species found in China, Indonesia, Philippines?
S. japonicum
what are two other species of schistosoma in Cambodia and Laos and in parts of Central and West Africa?
S. mekongi
S. intercalatum
what are some African transmission sites frequently visited by travelers that can cause schistosomiasis?
Banfora regions (Burkina Faso) and areas populated by the Dogon people (Mali), Lake Malawi, Lake Tanganyika, Lake Victoria, the Nile River, the Omo River (Ethiopia), and the Zambezi River
what is the incubation period of schistosomiasis?
incuation 14-84 days for acute schistosomiasis, and chronic asymptomatic infection can persist for years;
what is acute schistosomiasis called? symptoms?
penetration of cercariae can cause a rash that develops within hours or up to a week after contaminated water exposure;
Katayama syndrome - diarrhea, fever, headache, myalgia, respiratory symptoms
Eosinophilia;
painful hepatomegaly or splenomegaly also can occur
what is the cause of chronic schistosomiasis?
result of host immune responses to schistosome eggs;
eggs lodged in the capillaries of organs and cause granulomatous reactions;
where do S. japonicum and S. mansoni eggs most commonly lodge in the body?
S. japonicum and S. mansoni eggs most commonly lodge in the blood vessels of the liver or intestine - blood in the stool, constipation, diarrhea;
chronic inflammation can lead to bowel wall ulceration, hyperplasia, polyposis, and with heavy infections, to periportal liver fibrosis and splenomegaly
where do S. haematobium eggs typically lodge in?
Urinary tract - cause dysuria and hematuria;
calcifications in the bladder might appear late int eh disease.
can cause genital symptoms and has been associated with increased risk for bladder cancer;
eosinophilia might be present during chronic infection with any species
what is the rare consequence of schistosomiasis?
CNS manifestation - adult worms or eggs migrate and deposit in the spinal cord or brain - ectopic granulomas in the CNS and can present as transverse myelitis