anticoccidial drugs
TRANSCRIPT
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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