VPH - Quiz 2-2

drraythe's version from 2016-03-22 20:26


Question Answer
What kinda zoonoses are Taeniasis-Cysticercosis?Cyclozoonoses
How many hosts are reqd for Taeniasis/Cysticercosis?2 vertebrate hosts reqd to maintain the organism (humans may be 1 of them) (this is also the definition of a cyclozoonoses)
What is the definitive host for Taenia?HUMANS
What are the 2 types of cycles pertaining to humans w/ Taenia?Human-Swine
What does it mean if you are the definitive host of Taeniasis/Cysticercosis?You harbor the adult tapeworm
What is a Cysticercus?Larval stage
Definitive host of T. saginata?HUMANS (this is the cattle one)
Definitive host of T. solium?HUMANS
Cysticercus of T. saginata occurs in who?Cattle (saginata sounds Japanese makes me think of kobe beef)
Cysticercus of T. solium occurs in who?PIGS & HUMANS!!! (Down in their "soul", all humans are pigs)
What should you know about humans being the definitive host & able to host the cysticercus of ___? (ie, be the IH) (What organism & what should you know)T. solium. Humans alone could not maintain T. solium in nature, even if they can be DH & IH. (bc the cystercerci develop from eggs in the CNS & then they are unable to full mature/make eggs/pass eggs in feces)
How are animals infected w/ Taenia species?Pig (solium) or cow (saginata) ingests food contaminated w/ human feces containing tapeworm eggs which forms into Cysticerci in the muscle tissues. Animals are usually subclinically infected w/ ‘Cysticercosis”
(Beef infected w/ taenia Cysticercus is called what?)Measly beef
How are taenia species able to infect humans?Humans become infected by ingesting raw/ undercooked infected beef or pork containing Cysticerci which develops into the adult tapeworm
Which species of taenia's cysticerci cz problems for humans & what problems are they? How do humans get infected w/ this cysticerci?(Saginata DON'T cz problems) T. solium cysticerci DO cz problems in people. They cz Human Neurocysticercosis. This happens when a human ingests food or water contaminated w/ human feces that contain T. solium eggs. The eggs develop into cystersci in the human CNS to cz the neurocystercercosis
Neurocysticercosis happens w/ what sp? Symptoms?T. solium. Symptoms including seizures, encephalitis
What is happening in Human Cysticercosis?Cysticerci lodge in tissues &organs
What problems to humans get if they are the DH for taenia?Adult tapeworm in GI → usually just diarrhea if anything
Is there a Vx for pigs? Cattle?Yes for pigs. She didnt mention cattle so I assume no
How do you prevent Taeniasis-Cysticercosis in animals?Animals should not be exposed to food or vegetation contaminated w/ human feces
How do you prevent Human Taeniasis?Avoiding raw or undercooked pork (T. solium), pork & beef (T. saginata). Meat inspection reduces the risk of infxn
How do you prevent human Neurocysticercosis?Avoid contamination of soil & human & animal food & water w/ human feces that may contain eggs - Avoid the use of raw particularly human sewage for irrigation of pasture soil

Rocky Mountain Spotted fever (RMSF)

Question Answer
What is the agent which czs RMSF?Rickettsia rickettsii, an obligate intracellular bacterium
What are the Vertebrate Reservoir Hosts for RMSF?Rodents, lagomorphs (rabbits & hares) (rocky & bullwinkle-rockey is a rodent. They live by mountains)
What is the Invertebrate biological vector of RMSF?Ticks of the Ixodidae family
Dermacentor variabilis (American Dog Tick)
Dermacentor andersoni (Rocky Mountain Wood Tick)
Amblyomma spp.
Explain the Natural maintenance cycle(It is a complex of: Ticks & Small wild mammals, mainly rodents) Ticks become infected from feeding on rickettsemic rodents. Infected ticks can carry R. rickettsii for life. R. rickettsii circulates via ticks & is maintained primarily by transovarial & transstadial xmission in ticks. Infected ticks transmit the agent to other susceptible animals
What is the main way RMSF is maintained in tick populations?Infected ticks carry it for life - maintained primarily by transovarial (she creates infected eggs which cz infected larvae) & transstadial (if infected as a larvae/nymph, the infective agent continues tho as it develops into an adult) xmissin in ticks
What are the accidental dead end hosts for RMSF & how come they arent involved in the maintenance cycle?Dogs, opossums, humans. Not in maintenance cycle bc they do not become rickettsemic enough to transmit it to an uninfected tick
How do dogs/humans get RMSF?Tick bite: While attached to susceptible dog & human hosts, infected ticks transmit the agent in their saliva to these hosts
What is the role of the dog in human dz of RMSF?Dogs do not transmit R. rickettsii directly to humans, nor to uninfected ticks. However, they act as a sentinel, reports of concurrent infxns in dogs & owners, due to simultaneous exposure to infected ticks
How is R. rickettsii spread to humans?Tick bite, if not bite, ONLY by exposure to a crushed tick’s tissues, fluids or feces, which enter the body through skin wounds/lacerations/bites (so careful when removing ticks or handling blood & tissue specimens that may contain R. rickettsii)
How does RMSF clinically appear in...wildlife hosts?Infxn inapparent in the majority of wild life hosts
How does RMSF clinically appear in...dogs?Dogs may show clinical dz characterized by high fever, abdominal pain, depression & anorexia
Is RMSF reportable or notifiable? If so, when WHO gets RMSF is it the case?REPORTABLE when humans infected (rocky reportable & since there's people we only care about people)
What are the human clinical symptoms of RMSF?Clinical symptoms appear 2-14 days after tick bite. Flu-like symptoms. Fever, chills, muscle & joint pain
Also, the invasion of the human endothelial cells w/ the Rickettsia leads to a vasculitis that czs a Rash (Rocky Rash). This leads to symptoms - ~insomnia, delirium, circulatory, pulmonary complications, coma can occur
(How can you treat RMSF in dogs & humans?)If you suspect, treat anyway, response to Tx can confirm dx. Tx w/ Tetracycline, chloramphenicol, doxycycline. Tx greatly shortens the course of the dz.!!! Untreated can last wks/mos/ be fatal
How can you help prevent RMSF in pets?Early tick removal (careful not to smash them) to prevent xmission (take a little while for the agent to transmit through the bite), as well as vector control through Acaricides to kill ticks: (Environmental ones that are synthetic & EPA approved & also on the pet, like Frontline & others)
How can you prevent human exposure to vector?(Tick) Clear tick habitats (cut yo lawn), wear clothing, use insect repellents
Is there a Vx for RMSF?No. Not for anyone

Visceral larval migrans

Question Answer
What is/are the agent(s) for Visceral larval migrans?Nematode: Toxocara canis, Toxocara cati
What is the maintenance cycle/ reservoir for visceral larval migrans?Can be maintained w/in a single host but infective larval stage must develop from eggs deposited in the environment
What are the hosts for the agents of Visceral larval migrans?Dogs
Explain how the environment plays a role in the maintenance cycle of T. canis & T. catiThe nematode eggs require an environmental reservoir: Unembryonated eggs in dogs’ feces are not infectious until they are in the environment for 1-3 wks where they become infective (embryonated)
How do most humans get infected w/ T. canis & T. cati?Most infxns occur in children who eat dirt (pica) that contains embryonated (infectious) eggs & larvae migrate systemically. Also can happen w/ accidental ingestion of eggs on unwashed hands or in contaminated food/water, or rarely, infxns from eating undercooked meat containing Toxocara larvae (Vert xmission not known to occur in humans)
What is the human dz czd by T. canis & T. cati?Syndromes in humans due to migration of the larvae from the intestines to various organs & tissues:
(1) Visceral larva migrans
(2) Ocular larva migrans: retinal granulomas (larva)
How can you prevent T. canis & T. cati in dogs & cats?Deworming: Prevention of human infxns depends on the Tx/prevention of Toxocara infxns in animals by early, appropriate anthelmintic Tx
When are dogs/cats most likely to shed eggs?Pups from 3 wks-3 mos old excrete large numbers of T. canis eggs, this is the greatest hazard to humans
Cats shed T. cati, notably btwn the ages of 2-6 mos
How can you prevent Visceral larval migrans in humans?Prevent Children from eating soil. Children should not play in areas w/ animal feces. Also Wash hands after playing w/ pets /outdoor activities. Also Removal of dog / cat feces pre-embryonation of eggs so w/in 1 week of feces deposited in environment (prompt fecal removal from enviro) (don't put your pets feet in your mouth)
Cutaneous larval migrans (Grenada) - czd by what?Zoonotic. Happen from larvae of the dog & cat hookworms - A. caninum & Ancylostoma braziliense - don't complete lifecycle but stay in skin. Note that humans also have their own hookworms, where cycle is completed in humans


Question Answer
What is the agent which czs Sporotrichosis?Sporothrix schenckii
What is the reservoir for Sporothrix schenckii?The environment is the reservoir, but infxns can go directly from cutaneous lesions on the cat to humans
Is Sporotrichosis zoonotic?Not technically zoonotic, as it does not require a nonhuman vertebrate reservoir for its life cycle
(What are the 2 forms of S. schenckii & which is the 1 you see in animals/ppl?)(1) Mold: A dimorphic fungus that grows as a saprophyte mold in soil & on moss; rotting vegetation
(2) Yeast: When inoculated into skin it grows as a yeast
What are possible hosts of S. schenckii?Humans, cats, dogs, horses, other animals
How are humans usually infected w/ Sporotrichosis (Sporothrix schenckii)?In most cases of Sporotrichosis, entry is from the environment through broken skin or bite/scratch wounds, usually from cats → this is bc cats have large numbers of organisms present in skin lesions, mouth, nasal cavity & NAILS → xmitted through cuts & abrasions to humans. Rarely, inhalation can result in pulmonary dz
How is Sporotrichosis xmitted from people to people or animals to animals?TRICK QUESTION → Sporothrix schenckii is NOT passed directly from person to person or animal to animal… except for direct xmission from cats to humans. (probably bc cats have such high numbers). (Potential for cat-cat spread from a scratch or bite from a cat that has contaminated claws or teeth)
What are risk factors for humans to get Sporotrichosis?Persons handling thorny plants, sphagnum moss, or baled hay are at ↑ risk of getting Sporotrichosis. Outbreaks have occurred among nursery workers handling vegetation contaminated by the fungus. Humans acquire infxn from environment as cats do!! This is why it is NOT ZOONOTIC!! Cats, are not a true reservoir for this organism. The environment is the reservoir. However, cats can be a source of infxn for humans. NOTE: There is also a risk factor of lab workers getting it from culturing organism in lab
(How does Sporotrichosis present in a cat?)Nodular, ulcerative pyogranulomatous dermatitis. Lesions often observed on face, nasal planum & legs
Which cats are you most likely to get this from?Usually occurs in young cats & you will see nodular, ulcerative pyogranulomatous dermatitis. Remember that the cat acquires the infxn from the enviro
(How does Sporotrichosis present in people?)Nodular, ulcerative pyogranulomatous dermatitis. Lesions begin as painless pink, red or purple bumps usually on the hands. Bumps appear btwn 1-12 weeks after infxn, but usually appear w/in 3 weeks. Infrequently, disseminated & fatal Sporotrichosis affects the lungs, joints, or CNS & can be serious
What are some things you can educate clients on & do for prevention of Sporotrichosis?Inform clients (& vet staff) of the potential for xmission via cat lesions to humans through contact. Wear gloves to avoid direct contact w/ lesions; Wash hands after handling cat. After the gloves are removed, the hands should be washed thoroughly & disinfected w/ chlorhexidine, povidone iodine, or another solution w/ antifungal activity

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