Lec 21 - echinococcosis. screwworm, and tick paralysis

Question 1

what are the scientific name for Echinococcosis

Answer 1

Echinococcus granulosus (cystic echinococcosis)

echinococcus multiocularis (alveolar echinococcosis)

Question 2

what are the species involved with echinococcus

Answer 2

intermediate host: herbivores and omnivores such as sheep, swine, cattle, deer, and rodents

accidental IH: humans

definitive host: canines

Question 3

what is the geographic location of alveolar echinococcosis

Answer 3

confined to northern hemisphere: central and northern Europe, central asia, northern russia, northern japan, north-central united states, northwestern alaska, and northwestern canada

Question 4

what is the geographic location for cystic echinococcosis for humans and livestock

Answer 4

humans - 5-10% may occur in parts of argentina, peru, east africa, central asia, and china

livestock - prevelance found in slaughter houses in hyperendemic areas of south america varies from 20-95% of slaughtered animals

Question 5

what are the clinical signs of the cystic Echinococcosis/hydatidosis in people

Answer 5

(incubation period many years until hydatid cysts grow large enough to trigger CS)

cysts in liver cause abdominal pain, nausea, vomiting. cysts in lungs cause chest pain, chronic cough, and shortness of breath. cysts are less common in bones, kidneys, spleen, muscles, and central nervous system

Question 6

what are the clinical signs of alveolar echinococcosis in people

Answer 6

(incubation period 5-15 years) causes tumor-like lesions in liver, may also have lesions in spleen, lungs, and brain; weight loss abdominal pain, general malaise, hepatic failure

Question 7

what are the clinical signs of echinococcosis in animals

Answer 7

cysts in liver are condemned at slaughter, weight loss, decreased milk production and decreased fertility

Question 8

what is the morbidity/ mortality of echinococcosis

Answer 8

little to no morbidity in definitive hosts

cystic echinococcosis have low morbidity in livestock (usually slaughtered before cysts spread) and in humans

alveolar echinococcosis there is a 90-100% mortality rate in untreated cases. in long term treatment cases, the mortality rate is 20% with a 1- yr survival

Question 9

how is Echinococcosis transmitted

Answer 9

disease in humans occurs only from ingestion of cestode eggs excreted by the definitive host. the cestode eggs mature and from cysts in the intermediate/incidental host. The encysted viscera are ingested by the definite host where the parasite mature to their adult stages and reproduce

Question 10

what is the treatment for echinococcosis in humans

Answer 10

chemotherapy - albendazole, mebendazole or praziquantel, and surgery to remove cysts if possible

Question 11

how can Echinococcosis be prevented

Answer 11

sanitation and avoiding contact with untreated at risk dogs and foxes

• monthly deworming for pets in endemic areas
• not feeding encysted organs from livestock/ wild game and not hunting rodents
• encourage dogs not to defecate where livestock live

Question 12

is echinococcosis zoonotic

Answer 12

yes

Question 13

what is the scientific name for new world screwworm

Answer 13

cochliomyia hominivorax

Question 14

what are the species involved with new world screwworm

Answer 14

all warm blooded animals, birds, primary concern for livestock

Question 15

is new world screwworm zoonotic

Answer 15

yes

Question 16

where is screwworm endemic

Answer 16

cuba, haiti, the Dominican republic, and countries in south america

Question 17

where has screwworm been eradicated

Answer 17

north america

Question 18

what are the clinical signs of screwworms

Answer 18

mammals and birds may show: irritated behavior, head shaking, the smell of decay, evidence of fly strike, draining and enlarged wounds, presence of fly larvae (maggots) in wounds, decrease in milk production and appetite

Question 19

what is the morbidity/mortality or screwworm

Answer 19

death from screwworm is not typical; usually pathology results from secondary infection.

Question 20

what makes screwworm highly consequential

Answer 20

production cattle with screwworm become condemned and are not fit for slaughter, making this disease highly consequential

Question 21

how is screwworm transmitted

Answer 21

adult flies mate – they survied in the environment feeding on food/feces – female lay eggs in the wool/fur of its host (eggs can also be laid in wounds) – these eggs hatch – the larvae feed on debris and open wound flesh – eventually larvae drop to the ground, pupae form and adults emerge - then the cycle continues

Question 22

what is the most effective form of control of screwworm

Answer 22

prevention - fly control and vigilant screening

implementing sterile insect technique (SIT) - sterile male flies were introduced into the environment and produced sterile eggs and eradicate the population

Question 23

what is the treatment for screwworm

Answer 23

treatment through eradication - females only mate once during their lifetime, while males mate multiple times — sterile insect technique

Question 24

t/f new world screwworm is highly invasive

Answer 24

true

Question 25

is screwworm reportable

Answer 25

yes - because if its effect on livestock, an out break can have severe socioeconomic consequences

Question 25

what are some other names for tick paralysis

Answer 25

tick toxicosis or tick bite paralysis

Question 26

what are the species involved with tick paralysis

Answer 26

humans, dogs, cats, sheep, goats, pigs, horses, birds, and reptiles

Question 27

what are the 3 genera of ticks the effect humans

Answer 27

Ixodes, Dermacentor and amblyomma

Question 28

what are the 7 genera of ticks that effects animals

Answer 28

ixodes, dermacentor, amblyomma, Ripicephalus, haemephysalis, otobius, argas

Question 29

what is the geographic location for tick paralysis

Answer 29

north america, south america, europe, africa and asia

• most humans occur in north america and australia

Question 30

what are the clinical signs of tick paralysis

Answer 30

• rapid ascending lower motor weakness
• signs start in the hind limbs, followed by weakness in the front limbs, progressing to paralysis of all four limbs
• nerves in the head can be affected resulting in facial weakness, voice changes, swallowing problems or decreased muscle tone in jaw
• severe cases respiratory muscles may become paralyzed
• pain sensation is intact

Question 31

what is the mortality of tick paralysis

Answer 31

mortality could be as high as 12% if left untreated or misdiagnosed

Question 32

how is tick paralysis diagnosed

Answer 32

diagnosis is based in clinical signs. finding and removal of ticks from the patient and rapid resolution of CS after tick is removed.

Question 33

how is tick paralysis transmitted

Answer 33

neurotoxins secreted in saliva form a tick bite by females of certain species. peaks during spring and early summer

Question 34

how is tick paralysis controlled

Answer 34

treatment is exam for ticks and removal
- if left untreated it can lead to resp failure and death

tick antiserum is aval in Australia and not in the US

Question 35

how can tick paralysis be controlled or prevented

Answer 35

using tick control, monthly preventions, and checking pets for ticks

Question 36

what should be considered with small childeren and tick paralysis

Answer 36

acute ataxia

Question 37

is tick paralysis zoonotic

Answer 37

yes