Strongyloidiasis

Etiology

• Family Strongyloididae comprises of free living, parasitic and both forms.
• Parasitic form is parthenogenetic in nature.

Strongyloides species infection in various domestic animals:

Morphology

• Strongyloides eggs are blunt ends, thin shelled and contain fully developed embryos when passed in the faeces of host.

Host affected

• Piglets, foals, calves, lambs – neonatal infection (through colostrum) after birth – mobilization of arrested larvae in tissues of ventral abdominal wall of the dam, which are subsequently mobilized and excreted through milk.
• Dam is act as reservoir of larva for very young animal, clinical Strongyloidiasis in foals and pigs as a result of successive progeny from same dam causes heavy infection.
• S. ransomi  causes prenatal infection in pig.

Environment

• Larvae are not ensheathed and susceptible to adverse environmental condition.
• Warm and moist condition favours accumulation of infective larvae.

Pathogenesis

S. papillosus

• Catarrhal enteritis.
• Skin penetration by infective larvae causes erythematous reaction, which favours introduction of foot rot organism into skin around feet.

S. stercoralis

• In puppies during summer months causes catarrhal enteritis.

S. ransomi

• It infect mainly suckling piglets.
• Piglets get infection while suckling, because the infective larva is adhere on udder and teat.
• Piglets can also infected through skin penetration of larva from soil and litter.
• Protein losing gastroenteropathy.
• Erythematous skin lesion may be seen, pulmonary disorder is not frequent in natural outbreaks. verminous pneumonia in all animals, petechial/ ecchymotic haemorrhagic in lungs.

Clinical manifestation

• Skin lesion.
• Severe diarrhoea which may be blood stained, dehydration, anorexia, loss of weight and finally death (especially piglets mortality – 50 %).
• Foals – acute diarrhoea.

Immunity

• Young animals infected with few infected larvae develops marked immunity.
• Foals – satisfactory immunity occur15 to 23 weeks of after birth.

Diagnosis

• Based on clinical signs.
• Demonstration of eggs and larvae in faeces.

Treatment

• Sheep:
  • Thiabendazole @ 75 mg/ kg orally.
• Pigs:
  • Thiabendazole @ 50 mg/ kg through feed and Levamisole @ 5 – 10mg / kg.
• Dog:
  • Diethylcarbamazine @ 100 mg / kg
  • Dithiazanine @ 5 mg /kg (10 daily doses)
  • Pyvinium pamoate @ 20 mg /kg (5 days)
  • Thiabendazole @ 50 -75 mg/ kg – highly effective
• Foals:
  • Cambendazole @ 20 mg /kg
  • Fenbendazole @ 50 mg /kg

Prophylaxis

• For prenatal and transcolostral infection in anticipated cases, treat before manifestation of clinical signs.
• For pigs:
  • Mebendazole @ 72 – 104 mg / kg for daily 12 – 14 days prior to farrowing.
  • Levamisole @ 140 mg /kg – total dose.
  • Ivermectin -Single dose – 4 –16 days prior to farrowing.