Lec 21 - echinococcosis. screwworm, and tick paralysis Flashcards
(38 cards)
what are the scientific name for Echinococcosis
Echinococcus granulosus (cystic echinococcosis)
echinococcus multiocularis (alveolar echinococcosis)
what are the species involved with echinococcus
intermediate host: herbivores and omnivores such as sheep, swine, cattle, deer, and rodents
accidental IH: humans
definitive host: canines
what is the geographic location of alveolar echinococcosis
confined to northern hemisphere: central and northern Europe, central asia, northern russia, northern japan, north-central united states, northwestern alaska, and northwestern canada
what is the geographic location for cystic echinococcosis for humans and livestock
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
what are the clinical signs of the cystic Echinococcosis/hydatidosis in people
(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
what are the clinical signs of alveolar echinococcosis in people
(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
what are the clinical signs of echinococcosis in animals
cysts in liver are condemned at slaughter, weight loss, decreased milk production and decreased fertility
what is the morbidity/ mortality of echinococcosis
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
how is Echinococcosis transmitted
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
what is the treatment for echinococcosis in humans
chemotherapy - albendazole, mebendazole or praziquantel, and surgery to remove cysts if possible
how can Echinococcosis be prevented
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
is echinococcosis zoonotic
yes
what is the scientific name for new world screwworm
cochliomyia hominivorax
what are the species involved with new world screwworm
all warm blooded animals, birds, primary concern for livestock
is new world screwworm zoonotic
yes
where is screwworm endemic
cuba, haiti, the Dominican republic, and countries in south america
where has screwworm been eradicated
north america
what are the clinical signs of screwworms
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
what is the morbidity/mortality or screwworm
death from screwworm is not typical; usually pathology results from secondary infection.
what makes screwworm highly consequential
production cattle with screwworm become condemned and are not fit for slaughter, making this disease highly consequential
how is screwworm transmitted
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
what is the most effective form of control of screwworm
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
what is the treatment for screwworm
treatment through eradication - females only mate once during their lifetime, while males mate multiple times — sterile insect technique
t/f new world screwworm is highly invasive
true
