Introduction
Nematodes are unisexual and commonly called as roundworm. It is parasitic or free living, unsegmented, bilateral symmetry and usually elongate and cylindrical in shape with tapering ends. The colourless and translucent cuticle is covers the body. The underlying sub cuticular layer forms the cuticle known as hypodermis. Locomotion is done by undulating waves of muscle contraction and relaxation. The L1, eggs with L2 and L3 (strongylid) are the infective stage in the life cycle of nematodes. The development of infection in hosts viz ingestion, skin penetration, transplacental or transcolostral in direct life cycle while, ingestion of intermediate host or injection of L3 to host body in indirect life cycle. The life cycle of nematodes involves four moulting and five larval stages. Among these all 3 larval stages develops outside the host in open (in case of direct life cycle), however, in indirect life cycles these stages develops inside the intermediate host.
Various species of nematodes found in poultry
| S.no. | Name of parasites | Site |
|---|---|---|
| i. | Ascaridia galli (largest nematode of poultry) | small intestine |
| ii. | Heterakis gallinarum (ceacel worm) | caecum |
| iii. | Strongyloides avium | small intestine & ceacum |
| iv. | Syngamus trachea (gapeworm/ forked worm) | trachea |
| v. | Oxyspirura mansoni (eyeworm) | under nictitaing membrane |
| vi. | Subulura brumpti (pinworm) | caeca |
| vii. | Cheilospirura hamulosa | gizzard |
| viii. | Dispharynx spiralis | wall of oesophagus and proventriculus |
| ix. | Tetrameres mohtedi | proventriculus |
| x. | Capillaria caudinflata | duodenum |
| xi. | Capillaria obsignata | small intestine |
| xii. | Capillaria annulata | crop and oesophagus |
Ascaridia galli
- The eggs are ellipsoidal with smooth thick shell and oesophagus without a posterior bulb, while, precloacal sucker are present in males.
- Transmission of infection is done by ingestion of larvated (L2) egg with food or water or transport host (earthworm).
- The birds below three month of age are more susceptible.
- The predisposing factor like the deficiency of protein in the diet.
- The larvae cause catarrhal or haemorrhagic enteritis.
- Infection is common in free ranging in young birds while adults act as carriers.
- larvated egg remain viable for long time.
Diagnosis
- By faecal examination.
- The large adult is recovered during necropsy finding.
Treatment
- Piperazine adipate or citrate, phenothiazine and levamisole.
Prevention and control
- Treatment of infected birds.
- Isolation should be done of newly introduced bird in flock.
- Segregation should be adopted of young and adult birds.
- Regular cleaning of floor, feeding pen and drinking waterer.
- Provide proper ventilation.
- Regular deworming should be done.
- Proper sterilization of the litters before the placing of each new batch of birds.
- Provide ample quantity clean water.
- Offered feed free from the microorganism.
Heterakis gallinarum (caecal worm)
- Egg containing L2 is the infective stage.
- Eearthworm act as transport host.
- Transmission of infection is done by ingestion larvated egg with food or water
- It plays an important role in transmission of histomonas meleagridis (causes black head in turkey). this protozoan organisam are transmitted through the egg of this worm
Diagnosis, treatment and their control is similar to ascaridia galli infection.
Syngamus Trachea
- Adult males and females remain in permanent copulation such as ‘Y’ shaped appearance.
- Buccal capsule is well developed, cup shaped and up to 10 teeth at its base.
- Earthworm, slugs and snails act as transport host.
- Transmission of infection is done by ingestion of L3 larval stage with food.
- Eggs are ellipsoidal and have an operculum at both ends with embryonic cell.
- Adult birds usually act as carriers.
- The eggs and larva are very resistant and may survive several months in the soil.
- The earthworm act as a transport host where, L3 survive for years.
- Wild birds play an important role in the prevalence of infection.
- Prevalence is more during summer and rainy season (because earthworms are more active).
Symptoms
- Infected bird showed dyspnoea, asphyxia and gasping due to the blocking of air passage by worms load and secreted mucus.
- The affected bird opens their mouth widely and at the same time stretch out their neck assuming a gaping posture.
- In severe cases there may be death of the affected birds due to asphyxia.
Diagnosis
- Clinical Symptoms
- Finding the eggs in urine and worms at post mortem.
- By faecal examination to get characteristic egg.
Treatment
- Mebendazole,Thiabendazole and Febendazole.
Prevention and control
- Treatment should be done of sick bird.
- Regular deworming should be followed.
- Different species and age groups of birds should be reared separately.
- Rearing of birds on the moist ground having transport host should be avoided.
Oxyspirura mansoni
- The eggs of eyeworms, pass from the lacrimal duct and discharge through the dropping of the birds. Cockroach act as intermediate host.
- The infective stage develops in the cockroach which is taken up by the birds.
- Where they release larva wander up the oesophagus, pharynx and lacrimal duct reach to the eye and become adult.
Symptoms
- The eye of affected birds become inflammated with watery discharge and the nictitating membrane is swollen.
- A white cheesy material collects under the eyelids.
- Blindness occurs in heavy infection.
Diagnosis
- Detection of the worms in the eye.
Treatment
- Levamisole or Tetramisole Used topically or systematically to kill the parasite.
Prevention and control
- Control of cockroach by using insecticides.
- Provide the good hygienic measures.
- Isolation and segregation policy should be adopted.
- Sick bird should be treated properly.
Tetrameres mohtedi
- The infective stage develops in the cockroach and grasshopper.
- Transmission of infection is done by ingestion of infective stage.
Symptoms
- Parasite sucks blood and causes marked irritation and inflammation of proventriculus.
- Death may occur if bird is suffering from heavy infection, anaemiaand emaciation.
Diagnosis
- Clinical Signs
- Detection of larvated eggs in faeces
- During post mortem, female worm found in the glands of proventriculus
Treatment
- Levamisole, thiabendazole and haloxon etc can be used.
Prevention and control
- Use of fly proof wire net in the poultry house.
- Use of insecticides around the shed.
- Avoid the eating of intermediate host.
Capillaria sps
- It resembles morphologically, trichurid worms but size is smaller and hair like.
- The earthworm act as intermediate host.
- The egg have almost colourless cell, barrel shaped body with nearly parallel side.
- Bipolar plugs do not project.
Clinical Signs
- Inappetence, diarrhea, poor body growth, low egg production
Diagnosis
- Finding of eggs in faeces
Treatment
- Levamisole given in drinking water.
Prevention and control
- Control intermediate host like earthworm
- Proper cleaning of poultry house
- Proper deworming