ASCARIASIS

Prepared by: PRABHU KUMAR M D HVK 1225 Veterinary college Hassan

Ascariasis This disease is caused by ascarid worms

belonging to the family Ascaridae which includes

Ascaris, Parascaris, Toxascaris and Toxocara genera of vetertinarty importance.

Ascaris suum infectionAetiology:• Ascaris suum is a large parasite of pigs• Immature A. suum - found in sheep and cattle • A. lumbricoides - human beings No cross reaction between these twoEpidemiology:• Found throughout world• Young piglets are most susceptible. Adults have

resistant.Transmission:• Ingestion of eggs containg infective L2 through

contaminated feed and water

Pathogenesis: Pathology is due to migrating larvae

Eggs hatched in

SI

Liver (converted

to L3 & their

migration cause

damage )

Lungs and causes

transient pneumonia

Bronchioles, Bronchi, trachea, Pharynx

Coughed up and

swallowed into

intestine

In SI developed into adult

L2

BloodL3

L3

L3

Lay the eggs

Severe coughing in piglets

L/C

Ingestion of eggs

• Adult worms in intestine causes apparent damage of GIT epithelium, leading to diarrhoea.

• When there is heavy parasite load, bowel lumen get occluded by adult worms & Problem in the movement of bowel contents may occur (or) Intestine may rupture.

• Obstruction bile duct leads to jaundice.

Clinical findings:• During larvae migration, coughing and concurrently

pneumonia may also produced.• In acute-Dyspnoea, increased depth of respiration.• Piglets may die due to acute hepatic insufficiency.• Migrating larvae may result into latent infection of

Enzootic pneumonia.• Occlusion of bile duct by adult worms-Obstructive

jaundice.• Rupture of gut by severe obstruction- Peritonitis.• Vomition- presence of worms.• Diarrhoea.

Necropsy findings:• Milk spots in liver• Adults worms seen in intestine.• Liver is enlarged and congested.• Haemorrhages below the capsule of liver.• Bile duct obstruction – jaundice.

Diagnosis:• Clinical signs• History of endemicity of disease• Faecal examination-Thick, smooth shelled eggs.

Treatment:• Ivermectin/Doramectin @ 0.3mg/kg bw &

Fenbendazole @ 5mg/kg bw- against adult & larvae(L4).

• Febental @ 5mg/kg bw , Oxybendazole @15mg/kg bw, Enbendazole @ 5mg/kg bw, Thiophonate (or)Pyrental tarterate - only against adult worms.

• Piperazine compounds- Adult worms.

Parascaris equorum infection Ascariasis of equines is caused by Parascaris equorum.

Aetiology:• Parascaris equorum• Eggs are subglobulor with a thick pitted albuminous layer,

90-100micro meter in diameter.Epidemiology:• Parasite found throughout world infect horses, donkeys,

mules, and zebra. • Foals of 3-9 months of age are most susceptible.• After 6 months of age Immunity develops.• Summer season is highly conductive due to availability of

susceptible host(young foals) and the environmental temp is suitable for development of L2 inside eggs.

Important factors associated with high pathogenicity of parasite

• High fecundity- Millions of eggs per day and these are highly resistant to environmental conditions due to which eggs remain viable for several ears.

• Sticky nature of outer shell of eggs further facilitates passive diffusion of eggs.

Transmission:• Ingestion L2 containing eggs along with feed.

Pathogenesis:• Migrating larvae cause focal haemorrhages and

eosinophilic tracts in liver in liver which are converted to whitish areas after fibrosis.

• Also in lungs cause haemorrhages & eosinophils infiltration which later replaced by lymphocytes.

• Greyish-green lymphocytic nodule form around dead larvae in sub-pleural area(more in reinfection).

• 0ccasionally GIT occlusion (or) peritonitis by perforation.• Adult worms compete with host for nutrition leading to poor weight gain.

Clinical findings:• Frequent coughing & greyish nasal discharge.• Unthriftiness, poor weight gain, dull hair coat obstruction signs of gut in moderate to heavy infection.

Diagnosis:• Clinical signs• Confirmed by faecal examination-spherical brownish thick eggs having pitted outer coat.

Treatment:• Piperazine adepate @75-150mg/kg bw.• Ivermectin @ 0.2mg/kg bw.• moxidectin@ 0.4mg/kg bw.• enbendazole@ 7.5mg/kg bw.• Febental @ 6mg/kg bw.• Oxybendazole @ 10mg/kg bw.• Pyrental embroate @19mg/kg bw.

Drug resistance occur if we use same drug repeatedly for the treatment of the cases.

Toxocara infection Toxocara is an important ascarid worm found

in cattle, dogs & cats. It causes heavy mortality in young ones & retarded growth of the newborn animals.

Toxocara vitulorum - Cattle Toxocara canis - Dogs Toxocara cati - Cats

Toxocara vitulorum infection Aetiology:

• Toxocara vitulorum found in SI of calves & also recorded in sheep & goats.

Epidemiology:• World wide occurrence.• Commonly seen in calves.Transmission:• Contaminated feed and water having eggs with L2.• Transcolostral route- when an animal of above 6 months of

age ingests eggs containing L2 which may reach somatic tissue without developing & they become active around calving & migrate to udder & infect calves by transcolostral route/transmammary route.

• No prenatal transmission (transplacental).

Pathogenesis:

Eggs hatched

in SI

Liver (larvae

migration causes

damage )

Lungs and causes

pneumonia

Bronchioles, Bronchi, trachea, Pharynx

Coughed up and

swallowed into

intestine

In SI developed into L3,L4

& then adult

Ingestion of eggs

L2

L2

L2

L2

L2

L/C

By penetrating stomach wall

Through blood

• Larvae are present in greatest amount in colostrum for 2-5 days after calving though these are secreted up to 30days.

• Heavy infestation may leads death of calves.• Adult parasites cause irritation in GIT & diarrhoea

occurs along with malabsorption by the intestine.

Clinical findings:• Coughing and pneumonia.• Rough hair coat and anorexia.• Anaemia in severe cases• Loss of musculature & thigh muscles become thin.• Diarrhoea along with steatorrhoea having foul smell.• Malabsorption results in pot-belly condition.

• GIT perforation leads to peritonitis.• Heavy parasitic load ->Intestine obstruction ->calf may die.

Diagnosis:• History of prevalence of parasite in the herd & Clinical

signs.• Faecal examination-sub globular eggs & have thick pitted

shells(confirmatory)

Eggs in faeces can only be noticed by 3 wks of age if T/C infection occurs. Before that no eggs are passed

in faeces.

Treatment:• Pyrental salts @ 250 mg/calf -highly effective• Levamisole, febental, oxyfenbendazole , piperazine

can also be used. Repeat 2-3 times after every weeks interval to expel

all the worms.Prevention and control:• Treating pregnant dams by suitable antihelmintics

so that they do not shed L2 in colostrum.• Should allow the calves to graze on contaminated

pasture.• Bedding material and other left over should be

properly disposed.

Toxocara canis infectionAetiology:• Toxocara canis , it is up to 10cm long• Causes heavy mortality in young pups due to high

parasitic load.Transmission:• Ingestion of eggs containing L2.• Transplacental infection by L2, L2 migrates to foetal

lungs where they moult to L3 just before birth.• Transmammary route.• Paratenic hosts such as Rodents/birds may ingest egg

containing L2 travel to their tissue & remain as such, definite host get infected if they eat the flesh of p/h.

L/c :

Pathogenesis:• In mild infection no much damage in migratory phase.• In heavy infection migrating larvae result in sever

damage of lungs leads to pulmonary oedema.• Adult parasites cause mucoid enteritis, diarrhoea,

partial/complete obstruction & may also cause perforation and peritonitis.

• Human beings can also infected & they suffer from Visceral larva migration.

Clinical findings:• Pot-belly, diarrhoea & anorexia.• Vomition and adult parasite may present in parasite &faeces.• Coughing, increased RR, frothy nasal discharge.• Heavily infected pups may die due to massive lung

damage &oedema.

Diagnosis:• History of prevalence of disease & clinical signs.• Confirmed by faecal examination – sub globular eggs, brown in colour & have pitted shell.Treatment:• Pups should be dewormed @2 wks of age & again

after 2 wks, by using drugs like piperazine, mebendazole, fenbendazole (or) other benzimidazoles.

(Liver protectants should also be prescribed along with dewormers.)

• Pregnant bitches should also be dewormed.

Toxocara cati infection• This infects domestic cats, wild cats & other members of field.• Transmammary transmission is noticed- queen acts as chief source of infection for kittens.• Paratenic hosts play important role in spreading disease.• No migratory phase in development of parasite & damage is limited to intestine.• Important clinical signs- obstruction, pot-belly,

diarrhoea, poor hair coat, anorexia, poor growth & vomition.

• Controlling of infection by deworming and hygienic measures.

Prepared by: Prabhu kumar M D