Protozoan Parasites: Lecture 17 - Trichomonas & Histomonas Pages 10-18 Spencer Greenwood BSc, MSc, PhD, DVM Dept. of Biomedical Sciences Office: 2332N AVC-North Annex Phone: 566-6002 Home: 892-4686 E-mail: sgreenwood@upei.ca http://people.upei.ca/sgreenwood/index.htm
Trichomonosis Bovine Trichomonosis Trich Avian Trichomonosis Canker or Frounce Feline Trichomonosis Non-pathogenic Trichs Pigs, horses & dogs...
Bovine Trichomonosis Tritrichomonas foetus Infection of the reproductive tract Morphology Only a single life stage Trophozoite is the infectious stage pyriform shaped 10-25 um long with 3 flagella & an undulating membrane with a posterior free flagellum Do not produce cysts
Life Cycle Direct Transmitted by natural service Bulls Trophs in the prepuce, penis, epididymis & vas deferens Cows/ heifers Trophs in the vagina, cervix & uterus
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
Prevalence Bull infection rates 6-8% BUT as high as 44%!! Reports increasing: New Mexico Colorado Oklahoma Alberta...yes, Canada too!
Pathogenesis Invasion of the uterus Leads to placentitis which results in detachment, death & abortion of fetus Trophs may also invade the fetal tissues
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
Clinical signs Bulls No clinical signs of infection
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 http://www.indiancountryextension.org/extension.php?=24
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 tests @ weekly intervals
Treatment Cows/heifers: No treatment available 4 months sexual rest to clear infection ~3% remain as carrier cows Normal term pregnancy expected
Treatment Bulls: No approved drugs CULL ALL INFECTED BULLS
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
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
Avian Trichomonosis Trichomonas gallinae - Infection of the crop of birds
Trichomonas gallinae Infection of the crop of birds Disease known by many names: Canker pigeons, songbirds... Frounce Raptors Roup poultry & fowl
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 http://www.ucm.es/info/parasito/gallinae.jpg
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
Transmission
Pathogenesis Rapid disease 10-14 days Trophs invade upper intestinal tract Oral cavity, sinuses, pharynx, esophagus & crop
Pathogenesis Canker - yellow, caseous nodules
Pathogenesis Liver may be invaded by trophs (rare) Lesions on surface, solid white-yellow & circular
Clinical signs Difficulty swallowing Yellow-caseous mass, Drool, green- yellow mucus in oral cavity & dripping from beak Gape mouth Listless, ruffled & emaciated
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
Trich research in action
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
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 catteries @ International cat show First reports found that feral cats, same demographic - no trichs!
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)
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... http://www2.ncsu.edu/unity/lockers/proj ect/cvmaprhome/gookin_file2.htm
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 http://www2.ncsu.edu/unity/lockers/project/cvmaprho me/gookin_file2.htm
Diagnosis Direct fecal smear In pouch TF culture Medium selective for Trichs Polymerase chain reaction (PCR) @ CVM-NC State University Confounding organisms Other trichomonads, Giardia...
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!
Transmission - Cross infection?
Histomonosis Histomonas meleagridis Blackhead disease or Infectious enterohepatitis
Histomonosis Site of infection Cecum & liver Morphology Pleomorphic Various trophozoites Flagellate & amoeba stages 5-30 um long No cysts? Artist s rendering not mine
Transmission Fecal-oral Heterakis eggs Earthworm Mechanical vectors Flies Cloacal drinking Virulence/isolates?
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
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
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
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? http://www.vet.purdue.edu/courses/ai/vm 550/Spring%202003/Bird/fig8.jpg http://www.affrc.go.jp/ave M/Japanese/atlas/protozoa/ histomonas/histom1.jpg
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. 2007 Vet Record)
Amoebae, Ciliates & Coccidia