Protozoa - Coccidia - Eimeria

Question 1

What is schizogony?

Answer 1

multiple progeny from 1 cell

formation of merozoites

Question 2

What is sporogony?

Answer 2

Formation of sporozoites

Question 3

Apical complex features

Answer 3

Cytoskeletal and secretory functions

-> penetration and invasion

Question 4

What is a parasitophorus vacuole?

Answer 4

A bag that the parasite sites in to mask it from the hosts immune system. Also replicated and feeds in here.

Question 5

Apicomplexa replication

• Schizogony
• Gametogony
• Sporogony

Answer 5

• asexual -> merozoites (pathogenic stage)
• sexual - macro and micro gametes -> zygote -> unsporulated oocyst
• Asexual - sporulation of the oocyst in external environment or within the host (infective stage)

Question 6

Apicomplexa direct lifecycle

Question 7

Which species and what is the configuration?

Answer 7

Isospora

1 oocyst: 2 sporocyst: 4 sporozoite

= 8

Question 8

Which species and what configuration?

Answer 8

Eimeria

1 oocyst: 4 Sporocyst: 2 Sporozoite

Question 9

Which species and what is the configuration?

Answer 9

Sarcocystis

0: 2 sporocyst: 4 sporozoite

Question 10

Configuration of Cryptosporidium?

Answer 10

1 Oocyst: 0 sporocyst : 4 free sporozoite

Question 11

Non cysts forming coccidia

• lifecycle direct or indirect?

Answer 11

• Direct lifecycle
• Eimeria
• Cystoisospora
• Cryptosporidium

Question 12

Hosts of Eimeria

Answer 12

Birds, ruminants, lagomorphs (hare and rabbit)

highly host specific

Question 13

Eimeria adult site

Answer 13

• endogenous development in the intestinal mucosa

Question 14

Lifecycle of Eimeria

Answer 14

Oocysts in the faeces -> sporulation (sporogony) -> sporocyst and sporozoite -> infect a new host -> sporozoites released in gut -> invade host cells -> schizogony -> lyse host cell to release merozoites -> gametogony -> zygote -> oocyst

Question 15

Significance of coccidiosis due to Eimeria

Answer 15

Economic losses - poultry

Enteritis (watery/bloody diarrheo)

Question 17

Immunity to Eimeria

Answer 17

Immunity develops with exposure

-usually subclinical/asymptomatic infections

Question 18

Susceptibility to coccidiosis due to Eimeria

Answer 18

• naive animals (weaners)
• low immunity
• high dose
• overcrowding, stress, poor hygiene, poor nutrition

Question 19

Diagnosis of Eimeria

Answer 19

Post mortem (fresh)

• gross observation, predilection site, pathology
• mucosal smears/scrapings + fixed gut sections for histo

Ante mortem

• faecal floatation for unsporulated oocysts

Question 20

Control of Eimeria in poultry

Answer 20

Vaccinate

Hygiene

• ammonia based disinfectants
• desiccation
• treat and introduce
• biosecutiry

Question 21

Sporulation time of Eimeria

Answer 21

1-3 days

best at 21-30 degrees in humid conditions

Question 22

Anti coccidial agents

Answer 22

Ionophore antibiotic

Toltrazuril

Sulphonamides

Question 23

Cause of hepatic coccidiosis in rabbits

Answer 23

Eimeria stiedae

Question 24

Pathogenesis of E. stiedae in rabbits

Answer 24

-Merogony in the bile duct//gall bladder epithelium -> jaundice, diarrgoea, sudden death

Question 25

Important Eimeria of cattle

Answer 25

E. zuernii E. bovis

Question 26

Consuquenced of Eimeria in cattle

Answer 26

- calf diarrhoea/bloody scours - Production losses

Question 27

How to deal with Eimeria in cattle

Answer 27

Reduce overcrowding Coccidiostats in milk replacer, feed or drench with toltazuril

Question 28

Causes of coccidiosis in lambs and how old are they?

Answer 28

E. crandallis E. ovinoidalis 1-5 months old

Question 29

Prevention of coccidiosis in lambs

Answer 29

coccidiostats in feed - late gestation ewe and prior to weaning lambs

Question 30

Most important Eimeria in birds?

Answer 30

E. tenella E. necatrix

Question 31

Important Eimeria to remember

Answer 31

Question 32

Bird Eimeria

Answer 32