1. Parasitic disease diagnostic testing in poultry
Dr. Latif Ahmad (DVM-PhD), Assistant Professor, HOD

2. Progressive Examination Hints
Checking for some commonly encountered dis.
Students & start diagnostician must refer to:
Characteristic signs and lesions,
Diagnostic procedures, &
Characteristics of infectious agent to be covered in sp. dis

3. DIAGNOSING AVIAN ECTOPARASITES
Avian external parasites, or “ectoparasites,” (flies, beetles, mites etc.) are arthropods living on or in skin/feathers, using birds as both shelter & food source. Modern high-density, confined housing systems create conditions favoring development of manure-breeding flies & beetles associated with accumulated litter & northern fowl mites.

4. Three main poultry production facility types have their own pest problems & unique management needs.
Caged-layer houses: Deep pit below presents greatest fly- breeding pot. due to manure accumulation under cages.
Birds run free on a litter’s central portion surrounded on both sides by elevated slats supporting nesting boxes & hen feeders in breeder or broiler-breeder houses.
Dead air space under slats creates an area of high humidity, inhibiting manure drying & producing conditions conducive for fly ovi-position & maggot development.
Broiler houses: Dry litter supports high beetle populations.
B/c of direct bird-to-bird contact, northern fowl mites can spread rapidly in breeder houses.

5. Ectoparasites vary in their host specificity
Some ectoparasites (e.g., bird lice) living exclusively on birds.
Generalists (mosquitoes & bedbugs etc.) equally comfortable utilizing birds & mammals, freq. moving b/w groups during their lifetimes.
Others with intermediate host ranges (e.g., stick- tight fleas) prim. found on birds, but can develop on mammals.
3 most significant arthropod pests in poultry prod. are:
Flies,
Beetles, and
Mites

6. FLIES House fly (Musca domestica)
Little/lesser house fly (Fannia canicularis)
Other flies commonly associated with poultry
Blow flies (Calliphoridae),
Flesh flies (Sarcophagidae),
Dung flies (Sphaeroceridae) &
Fruit flies (Drosophilidae).

8. Beetles (بھونرا)
Beetle species associated with poultry litter & manure accumulations:
Can cause structural damage to poultry housing,
Serve as pot. dis. reservoirs
create community problems by migrating to nearby homes at cleanout.
Darkling beetles (Alphitobius diaperinus)
Hide beetle (Dermestes maculatus) and
Larder beetle (D. lardarius)

9. Hide beetle (Dermestes maculatus)

10. Common Larder Beetle (Dermestes Dermestes)

11. External Examination of Birds for Parasites
Lice & some mites found on the affected chicken.
Exam. roosting areas & cracks & crevices in houses & around the yards for
Red mites (Dermanyssus gallinae) or
Blue bugs (Argas persicus).

12. Mites - Northern fowl mite & Chicken mite
Northern fowl mite, Ornithonyssus sylviarum is most imp. mite on cagedlayers, breeders, range turkeys, & pheasants.
Chicken mite/Dermanyssus gallinae (red mite or roost mite) is an occasional problem in turkey breeder facilities & grow-out houses.
These parasites are:
Visible to naked eye &
Complete their life cycle in as little as 7-10 days.
Chicken mites have been known to spread fowl cholera.
They are transmitted to poultry via
Wild birds or
Rodents.

13. Northern fowl mite Ornithonyssus sylviarum
causes feather blackening and spoiling at various levels in birds

14. Red mites (Dermanyssus gallinae)

15. Red mites (Dermanyssus gallinae)

16. Mites - Quail mites
Quill mite (syringophilidae and gaudoglyphidae) lives in quills & feeds on fluids obtained by piercing calamus wall.
Calamus is hollow shaft of feather that runs in middle.

17. Mites - Scaly leg mites
Scaly leg mites (Knemidocoptes mutans) burrow under the leg scales of chickens, turkeys, pheasants, and other birds.
Neocnemidocoptes laevis var. gallinae (Depluming mites) are similar to, but smaller than, scaly leg mite.

18. Knemidokoptosis (scaly or chalky legs)

19. Knemidokoptosis (scaly or chalky legs)
Lesions (formation of crusts on legs) are sec. to an inflam. reaction comprised of
Adult birds are generally affected (hens, turkeys, pheasants, exotic birds).
Thickening of cut. epidermis
Released exudate
It is caused by Knemidokoptes mutans and characterized by:
Inf. by contact b/w birds.
Appearance of extensive, rough and hard crusts on the featherless part of the legs.
The control is done by
Isolation of affected birds,
Leg bathing with warm acaricide soln &
Warm vegetable oil that helps decrustation

20. Harvest Mites or Red Bugs or Chiggers
Chiggers, Trombicula splendens, Neotrombicula alfreddugesi, and Neoschongastia americana, also known as harvest mites and red bugs, are bright red and less than 1 mm long.
Birds on range may be exposed to chiggers, but housed animals are not at risk.
Trombicula splendens feed on all kinds of animals & are most common in damp habitats.
Common chiggers are prevalent in transition areas b/w forests & grasslands, swamp margins, berry patches & thickets.

21. Chiggers

22. Fowl ticks/Argas persicus/blue bugs
Rare pests of com. poultry.
During day these ticks secrete themselves in protected hiding places nearby.
Light red to dark brown,
6–9 mm long as adults,
Life cycle can be completed in as little as a month.
Wrinkled skin.
All life stages of fowl tick feed on blood, but can live for up to yr without feeding.
♀ fowl ticks lay their eggs in cracks & crevices near flock.
Fowl ticks are active at night, moving to birds & taking a blood meal, causing roosting birds to act uncomfortable.
Ticks can transmit various bacterial & rickettsial dis.

23. Blue bugs/
Soft tick/
Arachnida/
Fowl tick
(Argas persicus).

24. Lice
Chicken body louse, Menacanthus stramineus, & shaft louse (feather louse) and Menopon gallinae, are ectoparasites of layer & breeder chickens
These are chewing lice; feed on dry skin and feathers, with the entire life cycle (egg, nymph, and adult) occurring on the host. Female lice glue their eggs (nits) to host feathers.
These eggs hatch into nymphs in about 4-7days. Nymphs have the same feeding habits as adults and resemble adults, except that they are smaller in size.
Nymphs undergo several molts, reaching adulthood in about 3-4 wks.

26. Chicken body louse (Menacanthus stramineus)

27. (1.5 to 2.0 mm long).
Shaft louse or feather louse

29. Fleas
Fleas are rare in poultry facilities, but when they do occur, they are more common in breeder and grow-out houses.
1. The EUROPEAN CHICKEN FLEA (Ceratophyllus gallinae) is a nest flea that is fairly common in poultry facilities and in wild birds’nests, having been found infesting several dozen avian species.

30. (Echidnophaga gallinacea):
Fleas (Contd.)
STICKTIGHT FLEA/ SOUTHERN CHICKEN FLEA
(Echidnophaga gallinacea):
Adult females are permanently affixed to host via their mouthparts, which are tightly embedded in skin.
Females attach themselves and lay their eggs on face & wattles
Sticktight fleas may also attack mammals, esp. CANINES in close proximity to infested flock.

31. DIAGNOSING AVIAN ENDOPARASITES

32. Endoparasites
Worms living in the intestines of chickens fall mainly into four categories. 3 nematodes & 1 cestode:
Hairworms (Capillaria), only measure cm long.
Caecal worms (Heterakis), usually 1.5 cm long.
Nematodes/ Roundworms
Cestodes/Tape worms, usually 7 to 10 cm long, consisting of many small segments.
Ascarids: usually 5 to 7 cm (2-3 inches) long.

33. Endoparasites – Nematodes/Roundworms
Longitudinal folds, or alae, may be present at ant. (cervical alae) or post. (caudal alae) part of body.
Most imp. worms of poultry.
Nematodes/roundworms are usually spindle shaped with ant. and post. ends attenuated.
Nematode male usually can be distinguished from female by presence of 2 (rarely 1) chitinous structure(s) known as spicules, located in post. end of body.
Body covering, or cuticle, is often marked by transverse grooves.

34. Diagnosis of Endopararsites
Intestinal contents exam. will reveal without difficulty
Inf. of Capillaria will result in severe emaciation & mortality in both immature & producing flocks.
Roundworms &
Caecal worms/Tape worms.
Capillaria can usually be found when intestinal contents are washed through a fine mesh sieve.
In floor-housed breeders & com. layers red. in egg prod. occurs.

35. Nematodes/Roundworms - Capillariasis
Hairworms (Capillaria), measure cm long. Most imp. in quails.
Inf. of crop (Capillaria contorta) & Ingluvitis (inflam. of the crop) is associated with C. contorta. They may also live in esophagus.
Inf. of intestine (Capillaria obsignata) show muc. thickening & focal enteritis with C. obsignata.

36. Capillaria contorta embedded in the mucosal surface of the crop of a quail.

37. Male Capillaria obsignata having no spines on spicule & esophagus more than half as long as body.
Female C. obsignata having shorter esophagus as long as body.
Female C. obsignata characterized by vulva - slightly prominent (black arrow) & post. to union of esophagus & intestine (white arrow).

38. Nematodes/Roundworms - Capillarids
Parasitism can be diagnosed by exam. of muc. scrapings & fecal flotation. Collect mucous exudate & deep mucosal scrapings
Examine before a strong light or under low-power magnification for the presence of parasites.
Under magnification, look for characteristic bi- operculated ova i.e., bi- polar, lemon-shaped eggs in the female capillarids.
Press into a thin layer b/w two thick pieces of plate glass.

39. Nematodes/Roundworms - Capillarids

40. Nematodes/Roundworms - Ascaridia
Ascaridia: largest roundworms of birds. Most imp. in CHICKENS & TURKEYS
Ascaridia galli: most common Ascaridia; in jejunum
Adults live in lumen of small intestine.
Larval stages invade intestine.
Worms are easily seen on PM exam. in small intestine
Extensive A. galli inf. may:
Reduce egg prod. in floor-housed breeders & com. layers.
Cause death due to intestinal obstruction in birds which are:
Immunosuppressed or
Are affected by an intercurrent debilitating condition.

41. Large roundworms (Ascaridiasis) in the small intestine of a chicken
Large roundworms (Ascaridiasis) in the small intestine of a chicken. This is the most common worm of poultry, and is usually found in the middle portion of the small intestine.

42. Large roundworms in the small intestine of a chicken
Large roundworms in the small intestine of a chicken. Severe infestation may cause obstruction of the intestinal tract.

43. Ascarid worms (round worms) in the intestine

44. Heterakis gallinarum in caeca.
Female: mm long
Male: 7-13 mm long
It is usually relatively harmless; however it can carry ‘black head’ which normally affects turkeys & occasionally chickens & pea fowl.
Heterakis gallinarum in caeca.

45. Nematodes/Roundworms - Eyeworm
Other nematodes which may be encountered in subsistence or small-scale flocks include:
Oxyspirum mansoni
1.5 cm nematode in corner/beneath nictitating memb. of eye
It is carried by some insect (cockroach, fly, mosquito)

47. Nematodes/Roundworms - Gapeworm
Syngamus trachea (gapeworm or Y-shapped worm) – a 2 cm nematode in the trachea. Esp. imp. in pheasants

48. Nematodes/Roundworms - Proventricular Nematode
Tetrameres americana – a 3 mm spherical nematode beneath mucosa of proventriculus.

49. Nematodes/Roundworms - Cheilospirura hamulosa
Cheilospirura hamulosa – a 2.5 cm nematode causes severe gross lesions in gizzard (haem., ulcers & thickening of mucosa & cuticle) & single yellowish nodules on caudoventral muscle
Cheilospirura hamulosa

50. Cestodiasis/Tapeworms infestation
Numerous cestode species may occur in the intestinal tract and can be diagnosed at postmortem or by exam of feces.
Cestodiasis results in emaciation in mature flocks, esp. if severe infestation is exacerbated by malnutrition or immunosuppression.

51. Cestodiasis (contd.) Most commonly diagnosed cestodes include:
Raillietina tetragona - a 25 cm cestode located in the distal jejunum.
Davainea proglottina - a 4 mm cestode located in the duodenum.
Raillietina echinobothridia - a 30 cm cestode of jejunum resulting in nodular granulomas & catarrhal enteritis.
Choanotaenia infundibulum - a 25 cm cestode located in the distal duodenum and jejunum.

52. Cestodiasis (contd.) - Raillietinosis
It is caused by some representatives of Raillietina genus that parasitize in dif. areas of the intestine.
It is a cestodosis characterized by:
Diarrhoea (sometimes bloody) during acute stage &
Usual intermediate hosts are ants or other insects.
Emaciation to cachexia & anaemia during chronic stage.
Pathoanatomically, gross exam. reveals:
Haemorrhages with various intensities in intestinal muc.,
Catarrhal haem.
Enteritis &
Parasites throughout

53. Make fresh blood smears and air dry for staining by
Blood Parasites
Make fresh mounts, preferably with citrated blood, & examine under light- and dark-field illumination for viable organisms.
Make fresh blood smears and air dry for staining by
Giemsa’s,
Gram’s,
Wright’s, or
Other method.

54. Protozoa Protozoa contain all one-celled animals.
Its various classes are separated into 7 dif. phyla.
Two of these phyla contain species imp. in poultry:
Apicomplexa is characterized by presence of an apical complex in sporozoites, and all are INTRACELLULAR
Sarcomastigophora includes flagellates and amebas. Generally, they possess pseudopodia, flagella, or both as LOCOMOTOR ORGANELLES.

55. Protozoa - Apicomplexa
Genera of poultry parasites in this phylum include:
Sarcocystis,
Wenyonella,
Tyzzeria, and
Eimeria,
Cryptosporidium.
Isospora,
Haemoproteus,
Leucocytozoon,
Plasmodium,
Toxoplasma,

56. Blood Parasites (Contd.)
Haemoproteus, Plasmodium  & Leucocytozoon are harmful to a greater or lesser degree, depending:
Range of hosts they can infect,
Environmental stress,
Age,
Nutrition &
Availability of suitable insects (vectors) to transmit dis. b/w birds.
Avian red blood cells infected with Haemoproteus.

57. Blood Parasites (Contd.)
Leucocytozoons are most imp. blood protozoa found in birds & are spread by an intermediate host blackfly of Simuliidae family.
L. Smithi affects turkeys,
L. simondi affects geese & ducks, &
L. caulleryi affects chickens

58. Protozoa - Sarcomastigophora
Genera in this phylum, which are important to poultry, include
Histomonas,
Trypanosoma,
Chilomastix,
Entamoeba,
Endolimax, and
Spironucleus.

59. Sarcomastigophora
Histomonas meleagridis causing Blackhead (Histomoniasis, Enterohepatitis)
Trichomonads (Trichomonas gallinae)
Make wet mounts of affected areas, adding a little warm physiologic saline soln. if necessary to provide fluid, and
Darkening of head parts, esp. in turkeys, gave name to dis. (blackhead). Circular necrotic areas in livers with a crater- like center & cheesy cores in caeca.
Examine under a m/s for hexamita, histomonads & trichomonads

60. Histomoniasis. Circular yellow necrotic tissue surrounded with white rings of a turkey liver.

61. Protozoa (Contd.)
Encephalitozoon cuniculi, a protozoan in a 3rd phylum, Microspora, recently has been discovered infecting chickens & other birds.
Identified in GIT, urogenital organs & muscle.
In embryos, brain & heart also infected.
It is not known how widespread or imp. Microsporidians in poultry.
Egg-transmitted.
Embryo mortality, but usually unapparent.
The discovery of Cochlosoma associated with losses in turkeys & ducks suggests yet another emerging parasitic dis.
Inactivity, lameness, mild diarrhea, & wt. loss.

62. COCCODIOSIS

65. Coccidia Protozoa (Contd.)
Make wet mount smears of mucosal scrapings from various segments of intestine & cecal contents & examine directly under m/s:
Coccidia
Observe & note subserosa before incising intestine.
Suspended oocysts & merozoites &
Stages undergoing development in epi cells - tissue stages

66. Coccidiosis
The presence of faeces with blood, dysentery, or diarrhoea suggests coccidiosis.
Coccidiosis is one of the most important diseases of poultry worldwide.
Locally, it is a serious problem and one of the biggest causes of economic losses.
However, PM exams necessary to confirm Dx.
Greatly enlarged caeca distended with clotted blood confirm caecal coccidiosis,
It mostly occurs in rainy season, and is characterized by bloody diarrhoea and high mortality.
Whereas small intestine distended with blood confirms intestinal coccidiosis.
Mostly dis. of young birds.

67. Coccidiosis can be divided into 2 groups:
Caecal coccidiosis: Mainly caused by E. tenella in chickens up to 12 wks.
Lab. exam. shows haem. in caecal wall. After severe bleeding a core will be formed in lumen.
Small intestinal coccidiosis by
Mortality upto50 %.
E. acervulina,
Inf. birds are listless with bloody droppings, pale comb & lack of appetite.
E. brunetti,
E. maxima,
E. necatrix

70. Coccidiosis
Caecal coccidiosis in a 45-day-old cockerel. Note the bird is emaciated and anaemic, as evidenced by the yellowish discoloration of its beak, comb, and legs.

72. Coccididiosis
Caecal coccidiosis: Caeca are greatly enlarged and markedly distended with blood

73. Caeca are now cut open to reveal the presence of clotted blood.

74. Intestinal Coccidiosis by Eimeria Acervulina
E. Acervulina may affect birds of any age. E. acervulina is not normally very pathogenic, but in some cases considerable mortality may be seen. Birds infected show loss of weight, combs may be shriveled and a drop or even cessation of egg production in layers may be seen. At necropsy, haemorrhagic lesions of E. acervulina are seen throughout the upper portion of the affected intestine and also grey or whitish patches may be present.

75. Intestinal coccidiosis: The affected portion of the small intestine reveal the presence of clotted blood.

76. Intestinal coccidiosis: Affected portion of the small intestine revealing clotted blood is shown differently.

77. Intestinal Coccidiosis by Eimeria brunetti
E. Brunetti may affect birds of any age. E. brunetti is definitely pathogenic, in severe infections mortality can be high. Birds infected show emaciation and diarrhoea. At necropsy a white cheese-like material is found in the lumen of the lower intestine and rectum. The caeca and cloaca are inflamed. The gut wall is thickened.

78. Combined quail dis./ulcerative enteritis & Eimeria brunetti coccidial inf. in intes. of chicken. Note small ulcers in ceca & rectum. Diphtheritic membrane is due to coccidial infection

79. Intestinal Coccidiosis by Eimeria maxima
E. maxima may affect birds of any age.
E. maxima is less pathogenic than E. acervulina, necatrix and brunetti, mortality is generally low.
Diarrhoea, loss of weight and a drop in egg production of layers, will be seen; bloody droppings are common.
At necropsy the lower portion of the small intestine is dilated and the wall is thickened; the gut is filled with thick mucus, grayish, brownish or pinkish in color.

80. Intestinal Coccidiosis by Eimeria necatrix
Mainly in chickens up to 4 months of age. E. necratrix is very pathogenic.
Blood in droppings,
Birds listless & lose wt.
In layers, drop in egg prod. be observed.
Infection with E. necratrix may result in a two stage clinical outbreak of coccidiosis.
At necropsy:
Middle portion of intestine is affected, haem. will be seen.
Unopened intestine looks spotty, white areas (schizonts) intermingled with bright or dull red spots (haemorrhages) will be observed.
In the acute stage mortality may be high in the first week after infection.
In the chronic stage:

81. Intestinal coccidiosis in 10-wk-old grower chicken caused by E
Intestinal coccidiosis in 10-wk-old grower chicken caused by E. necatrix. Small intestine greatly enlarged & distended with blood

82. Coccidiostats
Practice to include low levels of chemotherapeutics in feed of birds. These chemicals are referred to as coccidiostats & as such keep in check development of p/s so that a pathological situation does not develop.
Rx of infected flocks may be carried out by administration of coccidiostats at a higher therapeutic level to affected birds.
There are certain products available which are specifically designed for Rx & which are not satisfactory for prevention.
However, coccidia can develop a resistance to all chemicals so far used for this purpose & so it is necessary to change from one chemical to another periodically.
These chemicals are sometimes referred to as coccidiocidal agents. Whenever administering these products, particular attention should be paid to dosage recommendation of manufacturer.

83. COMMUNICATING PARASITISM Dx

84. Immunosuppression Immunodysfunction may also be caused by parasites.
External parasites can also cause immunosuppresion through indirectly influencing non- infectious causes including
Internal parasites decrease immunity as do other infectious causes of immunosuppression including bacteria and viruses.
Chemicals,
Hormones,
Antibiotics,
Toxins,
Environmental stresses and
Lack of dietary ingredients.

85. Communicating the Owner
The report should include:
A verbal report or telephone call to the flock owner, manager, or service worker soon after completion of necropsy & initial tests is highly advisable.
Necropsy findings,
Results of lab. studies: histopathologic, serologic, cultural
Dx (temporary or final) & conclusions &
Recommendations.
Tentative Dx be offered pending further confirmation.
Owner is seeking prof. advice. Vet. should give his/her best finale & advice based on facts available.