Flatworms, fasciolosis, fascioloidosis Flashcards
Class trematoda
Flukes
-9000 species are known
-body is unsegmented
-Life cycle is direct or indirect
- 2 strong suckers
Fasciolosis zoonotic aspect
emerging food- borne, neglected tropical human disease.
2,4- 15 million people are infected, and 180 milllion are at risk of infection.
what is Fasciolosis
-liver fluke disease
- worldwide occurence in grazing animals
- most commonly a chronic disease, with no characteristic clinical signs
what is the name of the common liver fluke and where can you find it?
- Fasciola hepatica
- found in temperate areas, in the tropics and subtropics
africa and asia
what is the name of the large liver fluke and where can you find it?
- Fasciola gigantica
- in tropical and subtropical regions
africa and asia
host spectrum of F. hepatica?
most herbivorus mammals and humans
host spectrum of F. gigantica?
camel, cattle, buffalo, sheep, goat, wild ruminants (in order of adaptation)
Levels of adaptation of Fasicola hepatica to the host species:
Low resistance: (rapid development, long survival) : sheep, goat, rabbit, hare, mouse, rat
Delayed resistance: cattle, buffalo, camel, red and roe-deer, moufflon, guinea pig, horse, man
Early resistance: pig, dog, cat
Fasciola hepatica
common liver fluke:
Adult
- up to 5 cm long, 1 cm width
- leaf - like apparance, brownish grey
-tegument with spine
- oral sucker is apical, ventral sucker
egg:
- oval, 130- 145 um long, golden yellow, thin shell inside zygote
- one operculate
- 4- 50 thousands egg per day in sheep
site: bile ducts ( gall blatter) , rarely in other organs (e.g lungs)
longetivity of F. hepatica?
several years ( in sheep up to 11 years)
lifecycle and hosts of fasiciola?
- intermediate host: amphibious freshwater snail
- life cycle is indirect
MI–> SPO –> RE1 –> RE2 –> CE –> MCE(infective stage)
how can you get infected with fasiciola?
per os with metacercariae ( prenatal very rare in cattle)
prepatent period fasiciola?
F. hepatica : 8-10 weeks
F. gigantica: 12 weeks or more
acute fasxiolosis ( in sheep)
- massive and short intake of MC (metacercaria)
- no characteristic clinical signs
- sudden death may occur at 2-5 weeks after massive infection
- diagnose with necropsy
subacute fasciolosis
- massive but longer period of MC intake
- clincal and pathological signs: loss of appetite and weight, anaemia, peritoitis, enlarged liver, liver fibrosis, death, cholangitis
chronic fasciolosis
- moderate, prolonged intake of MC
- clinical pathological signs: oedema under the jaw( bottle jaw) , anaemia, rarely jaundice, hepatic fibrosis
under natural conditions in western europe, when are the highest adult fluke burden normally observed?
during winter and spring
in cool and temperate areas
infections of snails early in summer, apperance of MC from late summer or atumn
in areas of milder climates
overwintering of fluke larvae in snails, apparance of MC on pasture from spring or early summer ( summer fasciolosis)
egg count in acute fasciolosis?
no eggs in the faeces!!! ( eggs of fasciolosis are very simular to rumen flukes!)
detection of F. hepatica DNA from faeces
PCR can detect infections 2 weeks post infection, before serum antibody develops and eggs in faeces.
blood parameters in fasciolosis?
Elevated liver enzymes, eosinophilia, anaemia, hypoalbuminaemia
post mortem in fasciolosis
enlarged, haemorrhagic liver. liver chirrhosis, cholangitis
treatment for acute disease
-stop grazing, move to fluke free pastures or stables
- treat with triclabendazole ( risk of developing drug resistance in fasciola
treatment for subacute and chronic disease
any flukicidal compound, which is effective against flukes aged 6 weeks or older.
e.g : nitroxynil, closantel, rafoxanide, triclabendazole.
how to control Fasciolosis?
-active immunization is not possible
- treatment of the infected hosts, reduction o f snail habitats, forecasting
large american liver fluke disease occurence
north america, mexico, SA, endemic in central europa
veterinary significance is high in sheep and goat.
Fascioloides magna
-large american liver fluke
- giant liver fluke
- deer fluke
- adults: 7-10 cm
- site: in biliary ducts and/ or liver tissue
- eggs: 110-160 um with zygote
intermediate snail : galba truncatula as the only snail species
definitive host, and paratenic host of F. magna
Definitive host: deer –> eggs in the faeces
paratenic host: cattle –> no eggs in the faeces
