APICOMPLEXA

• Monoxenous


  Having a single host
• Monoxenous apicomplexans


  • Monoxenous coccidia (non-cyst forming coccidia)
  • Family Cryptosporidiidae
• Subclass Coccidea (Coccidia)


  • Typically intracellular parasites mainly of vertebrates
  • Asexually reproduce by schizogony and sexually by gametogony and syngamy
  • Have direct (monoxenous coccidia) and indirect (heteroxenous) life cycle
• Groups of coccidia


  • Monoxenous coccidia (non-cyst forming coccidia)
  • Family Eimeriidae
  • Family Klossiellidae
  • Heteroxenous coccidia (cyst-forming coccidia)
  • Family Sarcocystidae
• Family Eimeriidae


  • Endogenous stages are within the digestive tract mucosa or sub-mucosa and adnexa, and sometimes in the urinary system
  • The oocyst, the end stage of the life cycle in the host, undergoes sporulation in the environment
• Sporulated oocyst


  The infective stage or form, important in identification of members of the family and other coccidia
• Life cycle of Eimeria

  1. Sporozoite

  
• Endogenous stages of Eimeria necatrix in SI epithelium include schizonts, macrogametocytes, and macrogametes
• Sporogony


  Sporulation of oocysts, takes 2 days at normal temperatures
• Merogony/Schizogony


  Produces around 900 merozoites
• 1st generation meront/schizont


  Forms 900 merozoites, 2.5-3 days after infection
• 3rd generation meront/schizont

  Forms 4-30 merozoites, 5 days after infection
• 3rd generation meront/schizont


  Forms 4-30 merozoites, 7 days after infection
• Gamogony/Gametogony


  Produces oocysts in feces, 7 days after infection
• Clinical coccidiosis


  • Generally not a problem in the wild or on sparse pastures
  • Predisposing factors include high stocking density, high humidity, poor sanitation, and stress
  • Pathogenicity and clinical manifestations depend on certain factors
• Clinical signsof coccidiosis


  • Diarrheal enteritis (may or may not be bloody)
  • Poor weight gain
  • Weakness
  • Emaciation
  • Death
• Coccidiosis is self-limiting in the absence of re-infection
• Young animals are more commonly affected than older ones
• Immunity


  Recovered animals develop a specific and partial immunity
• Diagnosis


  • Finding oocysts in fecal smear
  • Clinical signs and finding lesions at necropsy
  • Polymerase chain reaction (PCR)
  • Shape analysis algorithms (COCCIMORPH)
• Anticoccidial agents


  • Chemical (clopidol, robenidine, decoquinate, amprolium, sulfonamides, sulfonamide-pyrimethamine combination, toltrazuril)
  • Ionophores (monensin, salinomycin)
  • Organics (steroidal sapogenin, oregano oil)
• Coccidiosis Preventive Medication Programs


  • Continuous feeding
  • Shuttle program
  • Rotation program
• Controlof Coccidiosis


  • Sanitation and disinfection
  • Avoid overcrowding
  • Chemoprophylaxis
  • Vaccination or controlled exposure to infection
• Important chicken coccidiosis

  • E. acervulina
  • E. brunetti
  • E. maxima
  • E. mivati
  • E. necatrix
  • E. tenella
• E. acervulina


  Most common chicken coccidiosis species, infects the intestinal tract
• E. necatrix


  A severe pathogen, causes congestion, hemorrhaging, necrosis, and bloody feces
• E. tenella


  A severe pathogen, causes bloody coccidiosis with frequent copious bloody discharges from ceca
• E. brunetti


  A moderately severe pathogen, causes thickening and sloughing off of intestinal lining, formation of fibrinous mass, and caseous cores in the ceca
• Oocysts of Eimeria spp.

  • E. maxima (nonviable)
  • E. necatrix (unsporulated)
  • E. brunetti (sporulated)
  • E. mitis/mivati (unsporulated)
  • E. tenella (sporulated)
• Other avian coccidiosis


  • Ducks (Wenyonella philiplevinei, E. boschadis)
  • Geese (E. truncata)
  • Turkeys (E. meleagrimitis, E. adenoides, E. dispersa)
• Bovine coccidiosis


  • Main pathogenic species are Eimeria bovis and E. zuernii
  • Affects young cattle, causes bloody diarrhea, progressive weight loss, and death in heavy infections
• Ovine coccidiosis


  • Main pathogenic species are Eimeria ovinoidalis and E. ahsata
  • E. ovinoidalis affects cecum and colon, causing severe hemorrhagic enteritis
  • E. ahsata affects small intestine, causing thickening, edema, and inflated Peyer's patches
• Caprine coccidiosis


  Main pathogenic species are Eimeria arloingi, E. christenseni, and E. ninakohlyakimovae
• Another form of bovine coccidiosis

  • Persisting, non-hemorrhagic diarrhea with continuous weight loss until cachexia lasting several weeks
• Surviving animals of bovine coccidiosis may regain weight for a long time or remain stunted
• Diagnosis of bovine coccidiosis involves signs and extremely high numbers of oocysts (50 000-500 000/g); note: ruminants normally excrete few Eimeria spp. oocysts
• Treatmentsof bovine coccidiosis 


  • Amprolium
  • Sulfa (listed previously)
  • Nitrofurazone
  • Toltrazuril
  • Diclazuril
• Preventionof bovine coccidiosis 


  • Sanitation
  • Good husbandry management
  • Anti-coccidials
• Eimeria ovinoidalis (the most pathogenic) and E. ahsata

  • Eimeria ovinoidalis affects the cecum and colon causing severe enteritis that may become hemorrhagic; E. ahsata affects the small intestine causing thickening, edema, inflated Peyer's patches and lower SI
• Eimeria bakuensis (E. ovina) in sheep


  • Causes white patches on the mucosa and sometimes polyps