Flatworms, fasciolosis, fascioloidosis

Question 1

Class trematoda
Flukes

Answer 1

-9000 species are known
-body is unsegmented
-Life cycle is direct or indirect
- 2 strong suckers

Question 2

Fasciolosis zoonotic aspect

Answer 2

emerging food- borne, neglected tropical human disease.

2,4- 15 million people are infected, and 180 milllion are at risk of infection.

Question 3

what is Fasciolosis

Answer 3

-liver fluke disease
- worldwide occurence in grazing animals
- most commonly a chronic disease, with no characteristic clinical signs

Question 4

what is the name of the common liver fluke and where can you find it?

Answer 4

• Fasciola hepatica
• found in temperate areas, in the tropics and subtropics
  africa and asia

Question 5

what is the name of the large liver fluke and where can you find it?

Answer 5

• Fasciola gigantica
• in tropical and subtropical regions
  africa and asia

Question 6

host spectrum of F. hepatica?

Answer 6

most herbivorus mammals and humans

Question 7

host spectrum of F. gigantica?

Answer 7

camel, cattle, buffalo, sheep, goat, wild ruminants (in order of adaptation)

Question 8

Levels of adaptation of Fasicola hepatica to the host species:

Answer 8

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

Question 9

Fasciola hepatica

Answer 9

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)

Question 10

longetivity of F. hepatica?

Answer 10

several years ( in sheep up to 11 years)

Question 11

lifecycle and hosts of fasiciola?

Answer 11

• intermediate host: amphibious freshwater snail
• life cycle is indirect
  MI–> SPO –> RE1 –> RE2 –> CE –> MCE(infective stage)

Question 12

how can you get infected with fasiciola?

Answer 12

per os with metacercariae ( prenatal very rare in cattle)

Question 13

prepatent period fasiciola?

Answer 13

F. hepatica : 8-10 weeks
F. gigantica: 12 weeks or more

Question 14

acute fasxiolosis ( in sheep)

Answer 14

• 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

Question 15

subacute fasciolosis

Answer 15

• massive but longer period of MC intake
• clincal and pathological signs: loss of appetite and weight, anaemia, peritoitis, enlarged liver, liver fibrosis, death, cholangitis

Question 16

chronic fasciolosis

Answer 16

• moderate, prolonged intake of MC
• clinical pathological signs: oedema under the jaw( bottle jaw) , anaemia, rarely jaundice, hepatic fibrosis

Question 17

under natural conditions in western europe, when are the highest adult fluke burden normally observed?

Answer 17

during winter and spring

Question 18

in cool and temperate areas

Answer 18

infections of snails early in summer, apperance of MC from late summer or atumn

Question 19

in areas of milder climates

Answer 19

overwintering of fluke larvae in snails, apparance of MC on pasture from spring or early summer ( summer fasciolosis)

Question 20

egg count in acute fasciolosis?

Answer 20

no eggs in the faeces!!! ( eggs of fasciolosis are very simular to rumen flukes!)

Question 21

detection of F. hepatica DNA from faeces

Answer 21

PCR can detect infections 2 weeks post infection, before serum antibody develops and eggs in faeces.

Question 22

blood parameters in fasciolosis?

Answer 22

Elevated liver enzymes, eosinophilia, anaemia, hypoalbuminaemia

Question 23

post mortem in fasciolosis

Answer 23

enlarged, haemorrhagic liver. liver chirrhosis, cholangitis

Question 24

treatment for acute disease

Answer 24

-stop grazing, move to fluke free pastures or stables
- treat with triclabendazole ( risk of developing drug resistance in fasciola

Question 25

treatment for subacute and chronic disease

Answer 25

any flukicidal compound, which is effective against flukes aged 6 weeks or older.

e.g : nitroxynil, closantel, rafoxanide, triclabendazole.

Question 26

how to control Fasciolosis?

Answer 26

-active immunization is not possible
- treatment of the infected hosts, reduction o f snail habitats, forecasting

Question 27

large american liver fluke disease occurence

Answer 27

north america, mexico, SA, endemic in central europa

veterinary significance is high in sheep and goat.

Question 28

Fascioloides magna

Answer 28

-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

Question 29

definitive host, and paratenic host of F. magna

Answer 29

Definitive host: deer –> eggs in the faeces
paratenic host: cattle –> no eggs in the faeces