Protozoan Parasites: Lecture 17 - Trichomonas & Histomonas Pages 10-18

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1 Protozoan Parasites: Lecture 17 - Trichomonas & Histomonas Pages Spencer Greenwood BSc, MSc, PhD, DVM Dept. of Biomedical Sciences Office: 2332N AVC-North Annex Phone: Home: sgreenwood@upei.ca

2 Trichomonosis Bovine Trichomonosis Trich Avian Trichomonosis Canker or Frounce Feline Trichomonosis Non-pathogenic Trichs Pigs, horses & dogs...

3 Bovine Trichomonosis Tritrichomonas foetus Infection of the reproductive tract Morphology Only a single life stage Trophozoite is the infectious stage pyriform shaped um long with 3 flagella & an undulating membrane with a posterior free flagellum Do not produce cysts

4 Life Cycle Direct Transmitted by natural service Bulls Trophs in the prepuce, penis, epididymis & vas deferens Cows/ heifers Trophs in the vagina, cervix & uterus

5 Transmission Cows/heifers Trophs during copulation Infections persist for weeks- months Usually recover but can be re-infected Bulls A.I. Trophs during copulation Bulls may be infected for life (carrier) Mature bulls > young bulls Rare - contamination

6 Prevalence Bull infection rates 6-8% BUT as high as 44%!! Reports increasing: New Mexico Colorado Oklahoma Alberta...yes, Canada too!

7 Pathogenesis Invasion of the uterus Leads to placentitis which results in detachment, death & abortion of fetus Trophs may also invade the fetal tissues

8 Cows/heifers Typically minimal Mild mucopurulent discharge Open cows Calf production decreases by 50-80% in newly infected herd Abortion before 5 months gestation Vaginitis &/or pyometra Retained fetus & membranes Leading to endometritus & sterility Increased calving interval Clinical signs

9 Clinical signs Bulls No clinical signs of infection

10 Diagnosis Trophs Preputial scrapings or washings (smegma) Vaginal secretions, vaginal washings Absorbed fetuses Avoid contamination with gastrointestinal trichs (nonpathogenic confounders) Distinct "rolling" motion Diff-Quick/iodine stain

11 Diagnosis In Pouch TF - culture kit Look for trophs under microscope Selective medium for Trichs Polymerase chain reaction (PCR) Immunofluorescent assay (IFA) Repeat sampling may be required to confirm infection status 3 weekly intervals

12 Treatment Cows/heifers: No treatment available 4 months sexual rest to clear infection ~3% remain as carrier cows Normal term pregnancy expected

13 Treatment Bulls: No approved drugs CULL ALL INFECTED BULLS

14 Control Bulls: Cull infected bulls & use noninfected or virgin bulls Pre-breeding exam Use A.I. Test all bulls for trich Younger bulls Reduce transmission Replace every two years

15 Control Cows: Maintain a limited breeding season ID & separate infected cows Sexual rest of 4 months or cull Buy only confirmed pregnant replacements Vaccine: Trich Guard Female herd only partial efficacy Annual re-vaccination No efficacy in Bulls

16 Avian Trichomonosis Trichomonas gallinae - Infection of the crop of birds

17 Trichomonas gallinae Infection of the crop of birds Disease known by many names: Canker pigeons, songbirds... Frounce Raptors Roup poultry & fowl

18 Morphology Trophozoite Single life stage Pyriform shaped 5-9 um, with 4 flagella & an undulating membrane with embeded recurrent flagellum Trophozoite or Trich is the infectious stage No cysts

19 Life cycle Transmission: Direct Oral-oral, contaminated waterers, bird baths, puddles... Moist bird feed! Trophs reproduce by binary fission T. gallinae & other Trichs are normal oral flora Avirulent & virulent strains STRESS

20 Transmission

21 Pathogenesis Rapid disease days Trophs invade upper intestinal tract Oral cavity, sinuses, pharynx, esophagus & crop

22 Pathogenesis Canker - yellow, caseous nodules

23 Pathogenesis Liver may be invaded by trophs (rare) Lesions on surface, solid white-yellow & circular

24 Clinical signs Difficulty swallowing Yellow-caseous mass, Drool, green- yellow mucus in oral cavity & dripping from beak Gape mouth Listless, ruffled & emaciated

25 Diagnosis Clinical signs & gross lesions (PM) Restricted to the upper portion of the digestive tract Direct smears - Definitive Dx Trophs in oral fluids or lesions in the mouth, crop or digestive tract Culture In Pouch technique useful Medium selective for Trichs Confounding non-pathogenic Trichs PCR

26 Trich research in action

27 Control & Treatment Eliminate infected birds & suspected carriers Avoid feeding pigeons to raptors in rehab Proper sanitation Source of fresh, clean food & water Prevent pigeons from contaminating water & food supply of domestic fowl Anti-flagellate drugs Metronidazole, dimetronidazole & ronidazole REDUCE STRESS

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31 Feline Trichomonosis Discovered in 1996 Problem in young cats in multi-cat households, catteries & shelters Tritrichomonas foetus Morphology identical to bovine trichomonad 31% infection in 117 cats from 89 International cat show First reports found that feral cats, same demographic - no trichs!

32 Transmission Trichomonads usually commensal organisms & cause no clinical signs Transmission route unknown No cysts, so trich/troph is infectious stage Direct cat to cat most likely Mutual grooming Multi-cat litter box? Trichs can survive ~6-24 hours in feces (moist but firm)

33 Clinical Signs Chronic large bowel diarrhea P.E. Waxing & waning Duration up to ~ 2 years May resolve spontaneously Cow-pie diarrhea w/wo blood & mucus Often with fecal incontinence Anus edematous & painful Dribbling feces, rectal prolapse... ect/cvmaprhome/gookin_file2.htm

34 Pathogenesis T. foetus colonizes mucosal surface of ileum, cecum & colon Less frequently found in colonic crypts lumen Infiltration of lymphocytes & neutrophils, loss of goblet cells in intestinal mucosa mild to severe lymphoplasmacytic colitis Mechanism unknown likely involves disruption of normal flora, adherence to the epithelium & induction of host cytokines & enzymes me/gookin_file2.htm

35 Diagnosis Direct fecal smear In pouch TF culture Medium selective for Trichs Polymerase chain reaction CVM-NC State University Confounding organisms Other trichomonads, Giardia...

36 Treatment Sanitation & hygiene Human infections? Reduce stress Numbers of cats No approved treatment Ronidazole: 30 mg/kg twice daily for 2 weeks Resolves diarrhea & eradicates infection!

37 Transmission - Cross infection?

38 Histomonosis Histomonas meleagridis Blackhead disease or Infectious enterohepatitis

39 Histomonosis Site of infection Cecum & liver Morphology Pleomorphic Various trophozoites Flagellate & amoeba stages 5-30 um long No cysts? Artist s rendering not mine

40 Transmission Fecal-oral Heterakis eggs Earthworm Mechanical vectors Flies Cloacal drinking Virulence/isolates?

41 Epidemiology Common in North America Histomonas remain viable within Heterakis eggs for 1-2 years Mainly affects young birds Turkeys 3-12 weeks old High mortality (50-100%) Chickens 4-6 weeks old High morbidity, low mortality

42 Pathogenesis Trophs penetrate Cecum & invade liver via the blood stream Cecal lesions Edematous & lumen is filled with yellow caseous smelly exudate Liver lesions Circular depressed yellowgreen to grey areas of necrosis (1-2 cm) ~ 10 days post infection w3.ufsm.br/.../ histomonastrofozoitofigado2.jpg

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44 Clinical signs 2-3 weeks post infection Hunched appearance, droopy wings & tail, ruffled feathers Anorexia & emaciation Black or cyanotic head (occasionally) Foul smelling, sulfur- coloured diarrhea

45 Diagnosis Clinical signs Brilliant yellow (sulfur) feces with cecal & liver lesions (PM) Histomonas on histo sections (liver & cecum) Cecal or liver scrapings Saline smear Beware confounding cecal flagellates Normal flora? 550/Spring%202003/Bird/fig8.jpg M/Japanese/atlas/protozoa/ histomonas/histom1.jpg

46 Treatment & Control Good sanitation practices Turkeys & chickens must be raised separately Control Heterakis gallinarum in birds & limit access to eggs & earthworms Prophylactic & therapeutic treatment? Antibiotic resistance emerging Tiamulin 25 mg/kg for five days (Birch et al Vet Record)

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48 Amoebae, Ciliates & Coccidia