Anticoccidial drugs By:Mohamed Khalid Ali Newera

• coccidiosis introduction

• Etiology

• life cycle

• Pathogenesis

• Economic losses

• Treatment

• Control measures

coccidiosis introduction

characterized by: 1.Host specific

2.Tissue specific

3.Immune specific

Definition : is a usually acute invasion and destruction of

intestinal mucosa by protozoa of the

generaEimeria or Isospora.

Etiology

Eimeria species (intracellular parasite) host-specific protozoa Oocyst survive for years. Dryness and direct sun are lethal.

Mode of infection

Ingestion of sporulated oocyst.

Mode of transmission

Mechanical transmission through persons

and equipements.

Life Cycle

Clinical signs

• Vomiting

• Immunosuppression

• anorexia

Dogs and

cats may

shed oocysts

in feces but

remain

asymptomatic

.

In poultry :

• Drop in egg

production

• Emaciation

,pale legs and

peak

1.Broiler growth and weight are reduced. 2.feed conversion rate is reduced by 5-10%. 3.increase in condemnation rate at processing. 4.increase in mortality rates. 5.increase the susceptibility to other disease agents.

Economic Importance:

in poultry

In other animal

Immunosuppressive effect

Cost of treatment

Decrease production

Mortility

Anticoccidial drugs

Characters of Ideal anticoccidials :

1-Efficacy : Broad spectrum activity.

2-Safety : Wide margin of safety , at least three-fold difference

between registered and toxic level.

3-Cost effectiveness : least effective cost.

4-Residues : Should be metabolized, excreted, without toxic

residues.

5-Carcass and meat quality : should not affect organoleptic

criteria.

Causes of Coccidiostat failure :

1. Not effective against all species of Eimeria

2. More than average exposure oocysts

3. Low inclusion level of Coccidiostat

4. Faulty management ( wet litter )

5. Intercurrent disease

6. Drug resistance after prolonged uses.

Ionophores

Category : Streptomyces

Actions: anticoccidials

Toxic effects : directly facilitates

Ca++ transport in cells and increased intracellular concentration of Ca++ in cardiac and skeletal muscle cells

Mechanism of action: facilitate transport of Na+ ion in cells and elevates the intracellular concentration of Na+ ion. This increased concentration of Na+ ion inhibits the certain mitochondrial functions such as substrate oxidation and ATP hydrolysis.

Monensin

Category : fermentation product of Streptomyces

Actions: 1. 1st antibiotic used as an anticoccidials. Due to its broad spectrum

activity, it acts on trophozoites and 1st generation schizonts. Its activity

is generally within 1st 2 days of life cycle of coccidian.

2. increases the weight gain and feed conversion and in some cases

causes suppression of necrotic enteritis

M.O.A: This drug has ability to form complexes with

sodium and potassium ions in the host and developing parasite.

Lasalocid

Actions: increases weight gain, feed conversion and

reduces the lesion in severe coccidiosis

Category : fermentation product of Streptomyces

Amprolium

Category : quarternized derivative

Action : active against E. tenella, E. necatrix and

E. acervulina and to lesser extent E. maxima.

N.B. Combination of amprolium with ethopabate, sulphaquinoxaline or even pyrimethamine extended and strengthened the spectrum of activity.

N.B. may lead to development of drug resistance

M.O.A. 1. thiamine antagonist and due to its close structural

similarity it blocks the thiamine receptors. 2.suppresses the sexual stages, gametogony and sporulation of oocyst.

side effect: thiamine deficiency

Treatment of toxicity : add thiamine

Uses : it is only agent which can be used in

laying birds both for prevention and treatment of outbreaks.

Nicarbazin

Action: broad spectrum activity and

effective against all Eimeria spp.

N.B. may lead to development of drug resistance

Uses: The drug is suitable for administration

to broiler flocks

M.O.A. can enter the cells of the coccidia and paralyze the

intracellular energy-supplying ATP which leads to the interruption of cellular energy supply and the cease of function of sodium-potassium ion pump which results in the abundant influx of sodium ions and with them the influx of abundant water which causes the intracellular imbalance of ions in the cells of the coccidia or the rupture of the cells and the death of coccidia occurs.

Side effect : 1.reduces both egg production 2. Reduces the proportion of fertile eggs that hatch. 3.causes depigmentation of eggs, mottled egg yolk and poor hatchability,

Sulphonamides

Action : broad spectrum of activity

against eimerian species and have coccidiostatic action.

M.O.A. inhibit growth in which Sulfonamide

and PABA (necessary for growth) is similar in nature

Sulphadimidine

Action : against E. tenella, E.

necatrix and other species of coccidia.

Side effect : The problem of this drug is that it interferes

with vitamin K synthesis in the intestine and resulting into prolongation of blood coagulation time. At higher doses it causes loss of egg production in laying hens and hyperplasia of the somniferous tubules of testicles of male birds.

Category : sulfonamide derivatives

Ethopabate

Category : monocyclic aromatics

Action : anticoccidial activity especially against

intestinal forms

M.O.A. competitor of PABA for absorption by

the parasite and interferes with folate synthesis.

Quinolones

M.O.A. inhibiting DNA gyrase

Action : anticoccidial activity

Buquinolate

Action : broad spectrum of activity against

all chicken coccidia

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