Cystic echinococcosis in a domestic cat:

an Italian case report

OIE Reference Laboratory for Echinococcosis

Istituto Zooprofilattico Sperimentale (IZS) of Sardinia

National Reference Laboratory for Cistic Echinococcosis (CE)

13th NRL Workshop, Rome, 24-25 May, 2018

E. canadensis G6

camel strain

E. canadensis G7

pig strain

E. canadensis G8-G10

cervid strain

E. equinus G4

equid strain

E. ortleppi G5

cattle strain

E. granulosus s.s. G1-G3

sheep strain

E. felidis

lion strain

Cystic echinococcosis (CE) is a parasitic disease of global importance caused by the larval stage

of Echinococcus granulosus sensu lato (s.l.). Taxonomic classification is still controversial. E.

granulosus s.l. comprises different genotypes: genotypes G1-G3 (E. granulosus sensu stricto),

G4 (E. equinus), G5 (E. ortleppi), G6-G7, G8, G10 (E. canadensis) and E. felidis (“lion strain”).

E. canadensis G6

camel strain

E. canadensis G7

pig strain

E. canadensis G8-G10

cervid strain

E. equinus G4

equid strain

E. ortleppi G5

cattle strain

E. granulosus s.s. G1-G3

sheep strain

E. felidis

lion strain

Echinococcus granulosus s. l. life cycle is indirect and includes definitive and

intermediate hosts. The adult tapeworm resides in the small intestine of wild and

domestic carnivores. Intermediate hosts, usually ungulates, are infected by ingesting

eggs released in the feces of definitive hosts.

E. granulosus s.s. (G1-G3)

E. granulosus sensu stricto (s.s.), and in particularly

G1 genotype, is responsible for the vast majority of

human CE worldwide (ca. 90%),

G1 is mainly transmitted within a dog–sheep cycle

Accidentally, other animals,

including humans, could

ingest eggs and contract

cystic echinococcosis acting

as aberrant hosts.

E. granulosus s.s. G1

Sardinia is considered an hyperendemic area with the highest hospitalization incidence rates

of human CE (>6,5/105 inhabitants) in Italy

Prevalence in intermediate hosts

More than 3.300.000 sheep in Sardinia

Cystic echinococcosis in cat

Cystic echinococcosis in cats has already been reported in the past few years in South

America, New Zealand and Europe. Recently, cats infected with the larval form of E.

granulosus s.s. were found in Uruguay, Russia, and Turkey.

CLINICAL CASE REPORT

The cat was brought to a private veterinary clinic in Sassari

ANAMNESIS

• 3-years-old neutered female cat

• kept indoor with outdoor access

to suburban surroundings

• Abdominal distension

• Anorexia

• Reluctance to movement

PHYSICAL EXAMINATION

• Dyspnea

• Apathy

• Abdominal palpation

Pain Presence of multiple

rounded masses

Ultrasound imaging reported a voluminous splenic mass with a

multiloculated structure and multiple intraperitoneal vesicles of different

dimension characterized by anechoic content and delimited by a

hyperechoic rim. In hydatids of large dimensions, a bilaminated structure

of the wall appearing as a double echogenic line separated by a

hypoechogenic space was evidenced.

ULTRASOUND IMAGING

CE1

Unilocular cyst, evidence of the wall, considered active

EXPLORATORY LAPAROTOMY

Following general anesthesia (isoflurane in oxygen) and surgical field disinfection the

peritoneal cavity was entered by midline incision and the abdominal organs examined.

Numerous hydatids disseminated in the whole abdominal cavity were found either free

or attached to the omentum, presumably secondary hydatids as a result of the rupture of

the primary splenic cyst.

EXPLORATORY LAPAROTOMY

EXPLORATORY LAPAROTOMY

Peritoneal hydatids, from 5 to 50 mm in diameter, presented thin walls and contained

semitransparent liquid. Fertility of hydatids was determined by microscopical observation of

protoscolices confirming that the parasite can complete full development in cats.

EXPLORATORY LAPAROTOMY

Unfortunately, samples fixation hampered evaluation of their viability.

INTRAPERITONEAL HYDATIDS

Peritoneal hydatids showed the

presence of an outer periodic-

acid-Schiff (PAS) positive

acellular laminated layer with an

inner cellular nucleated germinal

layer regarded as a suggestive

pattern of metacestodes of

Echinococcus genus. Brood

capsules and protoscolices with

their characteristic hooks were

also detected

SPLENIC CYSTS

A distinct encapsuled cystic mass of

65 mm in diameter protruding at

one extremity of the spleen was also

observed. On the cut section it

appeared sponge-like for the

presence of multiloculated cysts

displaying analogous histological

characteristics to peritoneal hydatids

except for the presence of a host-

produced fibrous adventitial layer

surrounded by inflammatory cells.

Molecular identification of DNA

extracted from protoscoleces

was performed by amplification

and sequencing of a short

fragment of the mitochondrial

cytochrome c oxidase subunit1

(cox1) gene.

MOLECULAR ANALYSIS

Sequence alignment showed also that it was 100% identical to the common haplotype

previously reported as dominant in Europe and found to be the most common also in

the Mediterranean basin

CE should be suspected in cats with abdominal distension

and US evidence of multiple peritoneal vesicles especially

in hyperendemic areas and in association with

immunosuppressive diseases

Molecular findings suggest that no specific E. granulosus

haplotype is necessarily related to infection in domestic

cats confirming the host multitropism of E. granulosus G1

genotype

The report of a clinical case of CE in a domestic

cat points out the problems dealing with

environmental contamination in urban contexts

and the implied risk for public health

CONCLUSION

Thank you