7 Flashcards

Question

Malaria prophylaxis and treatment

Answer 1

* Chloroquine and mefloquine are drugs of choice for prevention and treatment * drug resistance is a serious problem

Answer 2

Largely a man-made disease (clearing of forests, building of irrigation canals) * Eradication or control of mosquitoes (resistance to insecticides) * Protection against mosquito bites – Avoid rural areas at night – Long-sleeved shirts/long pants – Insect repellent – Bed netting

Answer 3

recognized as human pathogen (1976) * reported in humans worldwide * The most common symptom of cryptosporidiosis is watery diarrhea; other symptoms include dehydration, weight loss, abdominal pain, fever, nausea, vomiting * chronic, debilitating, and potentially life-threatening symptoms in immunocompromised

Answer 4

complex life cycle including both sexual and asexual phases (oocysts 4-6 µ) obligate intracellular protozoan which infects the intestinal epithelial cells of the host (typically in small intestine)

Answer 5

WATER * numerically the most important mode of transmission (contaminated drinking water) * recently numerous outbreaks associated with water parks/pools

Answer 6

PERSON-TO-PERSON * ingestion of oocysts due to poor hygiene (e.g., day cares, institutionalized patients) AUTOINFECTION * thin-walled oocysts are released into the lumen and cause autoinfection * responsible for chronic and life-threatening disease in immunocompromised ZOONOTIC * cattle serve as important reservoir hosts * calves with diarrhea can excrete up to 1010 oocysts/day * environmental contamination; veterinary personnel and animal handlers at increased risk (petting zoo visitors)

Answer 7

MICROSCOPY * oocyst shedding intermittent; multiple stools examined * concentration methods can be used when low oocyst shedding * wet-mounts or permanent stains are used (acid-fast) * Fluorescein-labelled IgG mAb is used in immunofluorescence microscopy

Answer 8

PUBLIC HEALTH EDUCATION * in endemic areas, avoid drinking tap water/ice cubes, raw fruits and vegetables unless you can peel them * immunocompromised patients should consider bottled water * exposure to temperatures above 60°C and below -20°C will kill oocysts because crypto is spread person-to-person, handwashing helps prevent infection * precautions are required when caring for patients with crypto diarrhea; lack of effective disinfectants against oocysts (nosocomial infections)

Answer 9

Identified as a coccidian protozoan parasite and named in 1993 * Cases reported in North, Central, South America, Caribbean, S.E. Asia, Europe, UK, India, Africa * Endemic countries include Nepal, Haiti, Peru, and Guatemala

Answer 10

Low infectious dose * Incubation period approximately 1 week * Profuse and prolonged diarrhea * Abdominal pain, nausea, vomiting, fatigue, fever, loss of appetite * Effectively treated with bactrim (trimethoprim-sulfamethoxazole)

Answer 11

microscopic examination of wet mount stool for oocysts (brightfield, differential interference contrast, autofluorescence) * staining methods (e.g. acid-fast)

Answer 12

Person-to-person transmission unlikely * Zoonotic transmission unlikely * Most earlier outbreaks were waterborne * 90-99% of cases in U.S. are foodborne * Numerous foodborne outbreaks in recent years

Answer 13

Prevalent world wide * Highest incidence in school-age children * Up to 50% of children in North America * More of a nuisance than a health problem * Eggs ingested (faecal-oral route)

Answer 14

Mild infection of caecum/colon * May cause itching (pruritus ani) leading to disturbed sleep, irritability * Scratching may cause secondary infections

Answer 15

Scotch-tape test of perianal area * Microscopic identification of eggs; adult female worms may also be present (8-13mm) * Drug of choice is pyrantel pamoate

Answer 16

Personal hygiene education for children (wash hands) * Discourage scratching, nail biting * Frequent bathing; regular change of underclothing, pajamas, and bedding

Answer 17

Small roundworm found worldwide in many carnivorous and omnivorous animals, including humans * Transmitted through ingestion of larvae in raw or poorly cooked meat * Survives as adult in small intestine; as larvae encysted in striated muscle

Answer 18

Trichinella spiralis (domestic form) - humans, swine, rats (responsible for endemicity) - horses! (probably fed animal products as supplement) Trichinella nativa (sylvatic or wild form) - humans, bears, wild boar, wolf, fox, walrus, etc

Answer 19

Symptoms dependent upon phase of life cycle * When larvae excyst in small intestine - diarrhea, abdominal pain, vomiting * When next generation of larvae migrate into muscle tissues - facial edema, conjunctivitis, fever, myalgias * Occasional life-threatening manifestations include myocarditis, central nervous system involvement, and pneumonitis

Answer 20

Thiabendazole effective against intestinal phase * Mebendazole and albendazole have some effect on tissue phases * Steroids may be used to reduce inflammation

Answer 21

Rodent control * Avoid garbage feeding to livestock * Inspection programs (trichinoscopy, digestion, ELISA) * Cooking /freezing (T. nativa very resistent to freezing

Answer 22

large tapeworm (10 m long) * Adult tapeworm inhabits the small intestine of humans and other fish-eating mammals * Larval stages in freshwater fishes (e.g. pike, trout, perch, whitefish, salmon) which act as intermediate hosts

Answer 23

Transmitted through the consumption of raw or poorly cooked freshwater fish containing infective larvae

Answer 24

* Most cases are asymptomatic * Abdominal pain, dizziness, fatigue, vomiting, diarrhea/constipation * Vitamin B12 deficiency with pernicious anemia

Answer 25

* Stool examination for eggs (microscopy) or proglottids (segments) Anthelmintic drugs effective (Praziquantel)

Answer 26

Large tapeworms (up to 20 m in length) * Adult stage only found in humans * Transmitted through ingestion of larvae in raw or poorly cooked meat

Answer 27

Symptoms (adult tapeworm) -mild abdominal complaints Diagnosis -Eggs or proglottids in stool -Serological techniques Treatment -Anthelmintic drugs (Praziquantel) -surgery