Trypanosoma, Leishmania, Giardia, Trichomonas, Histomonas

Question 1

General morphology

Answer 1

1. Monomorphic/ polymorphic
2. Large nucleus, kinetoplast, flagellum
3. Forms: TRYPOMASTIGOTE (infective form), epimastigote, promastigote, amastigote

Question 2

Transmission of trypanosomas

Answer 2

1. Cyclic: via arthropod vectors (biological vector) which is necessary for thier multiplication and getting into infective state
2. Non cyclic: only mechanical transmission by arthropod vectors

Question 3

Dourine - “Trypanosoma equiperdum”

Answer 3

(genetic variant of T. Brucei evansi + equiperdum)

1. Eq, donkey - veneral disease
2. Clinical signs: genital mucous membrane - inflammation. Skin- dollar spots (thorax+neck). Nerves- anesthesia, ascending motor paralysis
3. Diagnosis: peripheral blood sample , genital mucous scraoing, puncture of dollar spots.
   * Parasitaemia: motile trypanosomes (trypomastigotes) - centrifuge >Ht tube> btw buffy coat to plasma
   * Giemsa
   * Serology: test 2x with 3W interval

Question 4

Nagana

T. Vivax, Congolese, Brucei brucei

Answer 4

1. Eq, cattle, camel - tropical parts in Africa
2. Clinical signs: Lymphomegaly, splenomegaly , anemia (cattle)
   * Eq: limbs+genitillia oedema
   * Ca: anemia , myocarditis, ataxia
3. Diagnosis:Peripheral blood, dark ground/phase contrast microscopy (trypomastigotes detection)
   * Parasitaemia: motile trypanosomas in blood (btw buffy coat to plasma)

Question 5

Surra

T. Brucei evansi

Answer 5

1. Camel, horse , dog, Ru
2. Clinical signs: fever, lymphadenomegaly, abortion, odema. Eq: paralysis, dog; hemorrhages , ocular signs
3. Diagnosis: Giemsa of blood smear detecting trypomastigotes

Question 6

Giardosis

Answer 6

Zoonosis , mainly dog
2 forms: i Trophozoites (vegetative) intestine - KITE form pearl shape, symmetrical, 2 nuclei, 2 axostyles , 4 pairs of flagella
ii. Cyst (spore) - feces , oval, 4 nuclei

1. Clinical signs: usually symptomless , young dogs- malabsorption , pancreatic insufficiency , poor growth, emaciation. Yellow, slimy diarrhrea , loss of appetite , vomiting , abdominal pain.
2. Diagnosis: direct examination (x400) of fresh faecal sample mixed with saline and Lugal solution- MOVEMENT DETECTION. Giemsa , immunological methods - Ag detection - COPROANTIGEN TEST

Question 7

Trichomonas foetus

Answer 7

THREE anterior flagella , 1 posterior.
1. Clinical signs: Bulls are reservoir , check bulls before insemination. Rarely causes preputial inflammation , urethral discharge
Cows are effected the most - vestibulitis , vagitinitis , ascending endometritis , anoestrus, early abortion (before 4th month) often undetected (small foetus)

2. Diagnosis: i.washing preputium with saline , collecting genital discharges - centrifuge , direct examination, sedimentation. ii. Giemsa . iii. PCR iv. Serological
3. Necroscopy: greyish yellow papules on the chorion of the foetus

Question 8

Trichomonas Gallinae

Answer 8

FOUR anterior flagella , 1 posterior
Mainly young pigeons . Can also be turkey, chicken

1. Clinic signs: foul odor from mouth and crop, Visible yellowish pseudombrane , necrotic lesions in the mouth+ pharynx , apathy , diarrhrea, suffocation , cachexy.
2. Diagnosis: smear from the crop or esophageal lesions , dark ground/phase contrast microscope.
   Fresh sample - vividly moving lemon shaped .
3. Necroscopy: yellowish diphtheric membrane in mouth , larynx , esophagus .
   Hepatic form: necrotic lesions in liver
   Generlized form- necrotic lesions in the liver , heart , aur saces

Question 9

Histomonas meleagridis

Answer 9

“blackhead” , infectious enterohepatitis
Mostly young turkeys , chicken , guinea fowl

2 infection ways:

i. Flagellated form: (oviod , one flagellum) in caecum
ii. Amoeboid form: (round,no flagellum) in tissue , PLEOMORPHIC. Detection of parasites is difficult

1. Clinical signs: loss of appetite, diarrhrea, yellow feces , “blackhead (head cyanosis)
2. Diagnosis : smears from the edge of the lesion , dark ground/phase contrast microscope.
   *In vitro breeding of parasites from fresh carcass!
   PAS positivity and Gram negative . Flagellated anf amoeboid forms can be detected.
3. Necropsy: caecum: yellowish , necrotic , caseous material , thickened walls+ ulcers.
   Liver: cut dry surface , sharp edges , deep circular necrotic foci.
   *Generalized form of guinea fowl: Spleen , lung , kidney necrotic lesions with wet cut surface of liver.