Ancylostoma caninum

veterinary parasitology
Introduction
morphology
Life cycle
Pathogenesis
Clinical signs
Diagnosis
Treatment and Control

1. Ancylostoma caninum Dr. Dhaval F. Chaudhary ( B.V.Sc . & A.H.) College Of Veterinary Science And Animal Husbandry, AAU, ANAND

2. Introduction Family : Ancylostomatidae Sub family : Ancylostominae Genus : Ancylostoma Species : ancylostoma caninum Host : Dog Location : small intenstine Common name : Hook Worm of Dog

3. Morphology They are fairly rigid Grey or reddish in colour depending upon the amount of blood in the intestine. Buccal capsule is well developed It contains 3 pair of ventral teeth. Eggs are oval thin shelled contains 8 cell stages. The ant end bend dorsally. Male : 1-1.2 cm; Female : 1.4-1.6 cm

4. Life cycle

5. In A.caninum , infection occurs in four ways, Oral ingestion Skin penetration. Prenatal. Transmammary infection

6. Oral ingestion Following oral ingestion of infective larvae either directly develops to mature or the infective larvae penetrate the oral mucosa and follow the tracheal route of migration. Finally the infective stage reaches the intestine and develops to adult. Skin penetration Following skin penetration, the infective larvae reaches the lungs via circulation and then follow the tracheal route of migration. Finally enter the intestine where it develops to adult.

7. Prenatal infection In older bitches following oral ingestion or skin penetration, a few larvae directly develops to adult but majority of the larvae follows somatic migration and remain dormant in the tissue until pregnancy. In the pregnant bitches dormant larvae is activated by the hormonal influence. These activated larvae enter the foetus via placental circulation. The worms do not mature until birth of the pups. They mature with in 30 days of birth of pups and eggs can be seen in faeces. Prenatal infection is common in pups.

8. Transmammary infection The larvae passed to pups via colostrum they directly develop to adult without any migration. Paratenic host may also involved (rodents) infection is by ingestion of infected rodents.

9. Pathogenesis Heavy infection occurs in young puppies below one year old. Smaller breeds are severely affected than larger breed. Worms are attached to intestinal wall (mucosa) with the help of well-developed buccal capsule and suck the blood. The worms frequently change the site of attachment. Hence numerous necrotic foci are seen. Since anticoagulants are found in the secretion of worms the blood continuously oozes from the site of attachment. In heavy infection puppies becomes anaemic because each worms suck about 0.001 ml per day.

10. Development of anaemia  coincides with emerging L5 stage because it has developed buccal capsule (the anaemia is microcytic hypochromic ). In dogs due to skin penetration by L3 causes dermatitis and swelling of s/c tissue. There will be decrease in RBC - Hb content and also haemorrhage in the lungs and pneumonia due to larval migration.

11. Clinical sign Anaemia, it depends upon the age of the host, nutritional status and iron reserve. Mucous membrane will be pale, diarrhoea with bloody mucous and passing tarry red coloured faeces. Oedema of legs and dependant part, coat become dry and harsh in nature and stunted growth will be seen.

12. Pale Mucus membrane Oedema of leg

13. Diagnosis Clinical signs. Fecal examination: By fecal flotation method where the stool is mixed with a solution that causes the parasite eggs to float to the top of the solution and adhere to glass slide placed on its surface since there are many eggs produced daily and the eggs have unique appearance. In very young puppies detection is less reliable because it takes 2-3 weeks for hookworm larvae to mature and producing eggs.

14. Eggs of Ancylostoma

15. Treatment and control Disophenol - 7.5 mg / kg b wt. - s/c. Mebendazole - 40 mg / kg b wt. Tetramisole - 7.5 mg / kg b wt. – s/c . Fenbendazole - 20 mg / kg b wt or 100 mg / kg single dose 100% effective. Regularly deworming should be carried out for preventing infections.

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