Trematodes - flukeworms

Question 1

Paragonimus kellicotti

Answer 1

Common name: Lung fluke

Zoonotic: yes

Host: Dog, Cat, humans

Additional host: IH: 1. snail 2. crayfish

Characteristics: large eggs

Site of infection: Lungs

Mode of infection: Ingestion

Clinical signs: Intermittent cough

Life cycle: metacercariae infective stage

PPP: 4 - 5 wees

Diagnostic stage: eggs

Method of diagnosis: radiographs; sedimentation; formation of pulmonary cysts

Question 2

Nanophyetus salmincola

Answer 2

Common name: Salmon poisoning fluke

Zoonotic: yes

Host: Dogs, cats, humans

Additional host: IH: 1. snail 2. various salmon fish

Characteristics: yellowish-brown eggs

Site of infection: small intestine

Mode of infection: ingestion

Clinical signs: enteritis; salmon poisoning (Neorickettsia helminthoeca) - sudden fever, vomiting, diarrhoea, high mortality

Life cycle: Metacercariae infective stage

PPP: 1 week Diagnostic stage: eggs

Method of diagnosis: Sedimentation

Question 3

Alaria spp.

Answer 3

Common name: Intestinal fluke

Zoonotic: yes

Host: Dogs, cats, fox, and mink

Additional host: IH: snails and tadpoles; PH: frogs, snakes, rats, humans

Characteristics: distinct operculum on the egg

Site of infection: adult: small intestine; immature stages: lungs

Mode of infection: ingestion

Clinical signs: non-pathogenic; duodenitis in heavy infection

Life cycle: metacercariae infective stage

PPP: 5 weeks

Diagnostic stage: eggs

Method of diagnosis: sedimentation

Question 4

Platynosomum fastosum

Answer 4

Common name: Lizard poisoning

Host: Cats

Additional host: IH: 1. Snails 2. crustaceans; Obligate PH: lizard, geckos

Characteristics: operculated egg

Site of infection: bile duct

Mode of infection: ingestion

Clinical signs: lizard poisoning - palpable liver, jaundice, diarrhoea, vomiting, lethargy, emaciation, icterus

Life cycle: Metacercariae infective stage

PPP: 2 - 3 months

Diagnostic stage: eggs

Method of diagnosis: sedimentation; hyperplastic bile ducts

Question 5

*Fasciola hepatica

Answer 5

Common name: Liver fluke

Zoonotic: yes

Host: Cattle, sheep, and goats

Additional host: IH: Snails

Characteristics: operculated egg

Site of infection: liver

Mode of infection: ingestion

Clinical signs: Anaemia, hyperplasia, hypoproteinaemia

Life cycle: eggs –> miracidia –> IH –> sporocysts –> cercariae –> metacercariae –> adult

PPP: 10 - 12 weeks

Diagnostic stage: metacercariae

Method of diagnosis: sedimentation, ELISA of milk, elevated globulin and albumin; necrotic fibrosis in liver; “pipestem liver”

Question 6

*Fascioloides magna

Answer 6

Common name: Deer fluke

Zoonotic: no

Host: White tailed deer, Wapiti, caribou

Additional host: Dead-end host: cattle; aberrant host - sheep and goats; IH - snails

Characteristics: oval shaped adult

Site of infection: Liver

Mode of infection: ingestion

Clinical signs: sheep develop bottle jaw, death often occurs before egg production

Life cycle: metacercariae infective stage

PPP: 8 months

Diagnostic stage: eggs

Method of diagnosis: liver tissue destruction by larvae; faecal sedimentation

Question 7

Paramphistomum spp.

Answer 7

Common name: Stomach flukes

Host: Cattle, sheep and goats

Additional host: IH - snailes

Characteristics: ventral sucker at the posterior end

Site of infection: rumen

Mode of infection: ingestion

Clinical signs: enteritis, diarrhoea, anorexia, haemorrhage; secondary infection by Clostridium spp.

Life cycle: development in host in the alimentary tract

PPP: 7 - 10 weeks

Diagnostic stage: eggs

Method of diagnosis: eggs usually not fount, disease occurs before egg production