how many hosts are required for Taeniasis/cysticercosis?
2 vertebrate hosts required to maintain the organism (humans may be one of them) (this is also the definition of a cyclozoonoses)
what is the definitive host for Taenia?
what are the two types of cycles pertaining to humans with Taenia?
human-swine and human-bovine
what does it mean if you are the Definitive host of Taeniasis/cysticercosis?
you harbor the adult tapeworm
what is a Cysticercus?
definitive host of T. saginata?
HUMANS (this is the cattle one)
definitive host of T. solium?
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 AND HUMANS!!! (down in their "soul", all humans are pigs)
what should you know about humans being the definitive host and able to host the cysticercus of ___? (ie, be the IH) (what organism and what should you know)
T. solium. Humans alone could not maintain T. solium in nature, even if they can be DH and IH. (because the cystercerci develop from eggs in the CNS and then they are unable to full mature/make eggs/pass eggs in feces)
how are animals infected with taenia species?
Pig(solium) or cow(saginata) ingests food contaminated with human feces containing tapeworm eggs which forms into cysticerci in the muscle tissues. Animals are usually subclinically infected with ‘Cysticercosis”
(beef infected with taenia Cysticercus is called what?)
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 cause problems for humans, and what problems are they? How do humans get infected with this cysticerci?
(saginata DON'T cause problems) T. solium cysticerci DO cause problems in people. They cause Human Neurocysticercosis. This happens when a human ingests food or water contaminated with human feces that contain T. solium eggs. The eggs develop into cystersci in the human CNS to cause the neurocystercercosis
Neurocysticercosis happens with what sp? symptoms?
T. solium. Symptoms include ..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 with human feces.
how do you prevent Human Taeniasis?
Avoiding raw or undercooked pork (T. solium), pork and beef (T. saginata). Meat inspection reduces the risk of infection.
how do you Prevent Human Neurocysticercosis?
Avoid contamination of soil, and human and animal food and water with human faeces that may contain eggs-- Avoid the use of raw particularly human sewage for irrigation of pasture soil
Rickettsia rickettsii, an obligate intracellular bacterium
what are the Vertebrate Reservoir Hosts for RMSF?
Rodents, lagomorphs(rabbits and hares) (rocky and bullwinkle-- rockey is a rodent. They live by mountains)
what is the Invertebrate biological vector of RMSF?
Ticks of the Ixodidae family--> Dermacentor variabilis (the American dog tick), and Dermacentor andersoni ( Rocky Mountain wood tick), and Amblyomma spp.
explain the Natural maintenance cycle
(it is a complex of:Ticks and 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 and is maintained 1*ly by transovarial & transstadial transmission 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- maintains primiarly by transovarial (she creates infected eggs which cause infected larvae) and transstadial (if infected as a larvae/nymph, the infective agent continues though as it develops into an adult) xmissin in ticks
what are the Accidental dead end hosts for RMSF, and how come they arent involved in the maintenance cycle?
dogs, opossums, humans. not in maintenance cycle because 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 disease of RMSF?
Dogs do not transmit R. rickettsii directly to humans, nor to uninfected ticks. However, they Acts as a sentinel,reports of concurrent infections 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?
Infection inapparent in the majority of wild life hosts
how does RMSF clinically appear in...dogs?
Dogs may show clinical disease characterized by high fever, abdominal pain, depression, and anorexia
is RMSF reportable or notifiable? if so, when WHO gets RMSF is it the case?
REPORTABLE when humans infected (rocky reportable and 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 and joint pain. Also, The invasion of the human endothelial cells with the rickettsia leads to a vasculitis that causes a Rash (Rocky Rash). This leads to symptoms > insomnia, delirium, circulatory, pulmonary complications, coma can occur.
(how can you treat RMSF in dogs and humans?)
If you suspect, treat anyway, response to tx can confirm dx. Tx with Tetracycline, chloramphenicol, doxycycline. Treatment greatly shortens the course of the disease.!!! 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 transmission (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 and EPA approved, and also on the pet, like frontline and others)
how can you prevent human exposure to vector?
(tick) clear tick habtats (cut yo lawn), wear clothing, use insect repellants.
what is/are the agent(s) for Visceral larval migrans?
Nematode: Toxocara canis, Toxocara cati
what is the maintainance cycle/ reservoir for visceral larval migrans?
Can be maintained within 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, cats, humans
explain how the environment plays a role in the maintainance cycle of T. canis and T. cati
the nematode eggs Require an environmental reservoir: Unembryonated eggs in dogs’ faeces are not infectious until they are in the environment for 1-3 wks where they become infective (embryonated)
how do most humans get infected with T. canis and T. cati?
Most infections occur in children who eat dirt (pica) that contains embryonated (infectious) eggs & larvae migrate systemically. Also can happen with Accidental ingestion of eggs on unwashed hands or in contaminated food/water, or, rarely, Infections from eating undercooked meat containing Toxocara larvae. (vert transmission not known to occur in humans)
what is the human dz caused by T. canis and T. cati?
Syndromes in humans due to migration of the larvae from the intestines to various organs and tissues---> (1) Visceral larva migrans (2) Ocular larva migrans: retinal granulomas (larva)
how can you prevent T. canis and T. cati in dogs and cats?
Deworming: Prevention of human infections depends on the treatment/prevention of Toxocara infections in animals by early, appropriate anthelmintic treatment.
when are dogs/cats most likely to shed eggs?
Pups from 3 wks - 3 mths old excrete large numbers of T. canis eggs -greatest hazard to humans. Cats shed T. cati, notably between the ages of 2 + 6 mths.
how can you prevent visceral larval migrans in humans?
Prevent Children from eating soil.Children should not play in areas with animal faeces. Also Wash hands after playing with pets /outdoor activities. Also Removal of dog / cat feces pre-embryonation of eggs so within 1 week of faeces deposited in environment (prompt fecal removal from enviro)
(Cutaneous larval migrans (Grenada)- caused by what?)
zoonotic one happen from larvae of the dog and 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 so this isnt zoonotic then
The environment is the reservoir, but infections 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 two forms of S. schenckii and which is the one you see in animals/ppl?)
(1) Mold: A dimorphic fungus that grows as a saprophyte mold in soil and 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 with Sporotrichosis (Sporothrix schenckii) ?
In Most cases of sporotrichosis, Entry 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 and NAILS--> transmitted through cuts and abrasions to humans. Rarely, inhalation can result in pulmonary disease.
how is Sporotrichosis transmitted 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 transmission from cats to humans. (probably because 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 increased risk of getting sporotrichosis. Outbreaks have occurred among nursery workers handling vegetation contaminated by the fungus. Humans acquire infection 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 infection 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, and 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 between 1-12 weeks after infection, but usually appear within 3 weeks. Infrequently, Disseminated and fatal sporotrichosis affects the lungs, joints, or CNS and can be serious.
what are some things you can educate clients on, and do for prevention, of sporotrichosis?
Inform clients (Vet staff) of the potential for transmission via cat lesions to humans through contact. Wear gloves to avoid direct contact with lesions; Wash hands after handling cat. After the gloves are removed, the hands should be washed thoroughly and disinfected with chlorhexidine, povidone iodine, or another solution with antifungal activity.
Pages linking here (main versions and versions by same user)