25 – Parasites III

Question 1

Coccidiostat

Answer 1

• Arrest development of the parasite, but do NOT kill COCCIDIAL stages
• Long term preventative drugs

Question 2

Coccidiocide

Answer 2

• If KILL most of the coccidial stages
  o More in later stages when can see clinical signs (ex. diarrhea)

Question 3

Coccidiostat and coccidiocide

Answer 3

• Many vary between them
  o Depends on duration of treatment, dosage and species of coccidia

Question 4

3 different label claims regarding coccidia

Answer 4

• TREATMENT of coccidiosis: when clinical case
• CONTROL/PREVENTION of coccidiosis: coccidiostats
• Reduction in FECAL SHEDDING

Question 5

Coccidiosis therapy: ‘groups’

Answer 5

• **Ionophore class (preventative)
  o *Monensin (Rumensin)
• Sulfonamides and potent. Sulfas
• Amprolium (Amprol)
• Toltrazuril (Baycox)

Question 6

Ionohores

Answer 6

• Old drug class
• Widely used as prophylaxis for coccidia in POULTRY and CATTLE
• Generalized inhibitory activity against ALL coccidial stages
• Act by Na/K pump activation and disruption of electrolyte balance
  o Also metal cation transport into cell, osmotic
• *other indications besides coccidosis as well

Question 7

Ionophores are good for coccidiosis prevention

Answer 7

• Not so great for treatment?
• Most have an ‘aid in prevention’ label claim
• *coccidiostat (arrest development) indication in broilers/turkeys, calves, sheep, rabbits

Question 8

What are some examples of ionophores?

Answer 8

• **Monensin (cattle)
  o *very large bolus: if use on a too small of animal=stuck in animal
• Lasalocid
• Salinomycin
• Narasin, nicarbazin
• Maduramycin
• *feed additive

Question 9

Ionophore toxicity and potentially death

Answer 9

• Especially in HORSES, also in dogs
• Disruption of Na/K ATPase and/or heavy metals/osmotic balance in CARDIAC and SKELETAL MUSCLE cells

Question 10

What are some common reasons for ionophore toxicity?

Answer 10

• Ionophore containing feed meant for pigs/poultry/calves is ingested by horses on same farm
• Mistaken delivery of ionophore-containing feed
• Incorrect ionophore concentration in feed

Question 11

What are the other indications for monensin?

Answer 11

• Antibiotic: will kill specific Gram-positive bacteria (ex. Strept. Bovis)
  o Osmotic disruption=increase propionate and decrease methane production
• Improved feed efficiency in feed lot cattle=increased weight gain
• Aid in reducing bloat in cattle grazing on legume pasture
• Reduction in fecal sheading of MAP in Johne’s disease herds
• Decrease rumen lactic acid production after acute CHO ingestion

Question 12

Specific dairy claims of monensin

Answer 12

• Aid in prevention of ketosis in lactating dairy cattle
• Reduced milk fat in lactating dairy cows
• Minimizing loss of body condition during lactation in dairy cows
• Improving feed efficiency of milk protein production in lactating dairy cows

Question 13

Sulfonamides (‘sulfas’)

Answer 13

• Old fashioned antibiotics
• **Can be used for cases of CLINICAL disease associated with coccidiosis
• *analogue of PABA (what bacteria need for DNA)
  o Interrupts synthesis of folate in bacterial and coccida
• Ex. Sulfamethazine: calves, sheep, poultry

Question 14

Amprolium (Amprol, AmproMed)

Answer 14

• Thiamine analogue
• Important for PREVENTION of coccidial disease, but not for clinically affected animals
  o Producers like to use it as a treatment=probably doesn’t work that well (need dose just right)
• Oral solutions and feed solutions available for poultry and calves

Question 15

Coccidia are more sensitive to thiamine effects than mammals (but not that much difference)

Answer 15

• But overdose is significant
  o Clinical sign of thiamine deficiency: polioencephalomalacia
• *treatment with thiamine might be successful, especially early on

Question 16

Deccox (Decoquinate): coccidiostats

Answer 16

• Able to add it to milk replacer
• *very beneficial for GOATS! (kids usually separated from moms)

Question 17

Toltrazuril (Baycox)

Answer 17

• Registered for use in piglets, lambs and calves
  o Variable for REDUCTION IN SHEDDING and treatment of clinical infection
  o *need to pick a window before the animals are exposed=need the dose at the right time
• *prolonged withholding time (48-70 days, should be okay since using early in life)
• Very expensive (people use compounded=not great)

Question 18

Forceris (Toltrazuril and iron supplement for pigs)

Answer 18

• IM behind the ear
• 70 day withdrawal period

Question 19

What are some extra-label uses of toltrazuril (Baycox)?

Answer 19

• Treating coccidiosis in puppies and kittens (other parts it is licensed)
• Effective for control of coccidiosis in poultry

Question 20

Ponazuril (toltrazuril metabolite): Marquis

Answer 20

• Aid in REDUCING clinical severity of Equine Protozoal Myeloencephalitis caused by Sarcocystis neurona in horses
• Oral paste in dial-a-dose syringe
• Administered daily for 28 days
• EXPENSIVE! ($250 per multi-dose tube)
• *BIG DEAL IN THE STATES! (know horses travel history, can show up years later)

Question 21

Halofuginone (Halocur, Halagon)

Answer 21

• Does NOT work to treat Cryptosporidium

Question 22

Clindamycin: lincosamide (macrolide) category of antimicrobials

Answer 22

• Antirobe oral drops or capsules
• Wide variety of antibacterial label claims
• High volume of distribution: good concentraitons in CNS

Question 23

Clindamycin extra-label use

Answer 23

• Toxoplasmosis and neospora in small animals

Question 24

Treatment of Giardia infections: 2 classes

Answer 24

• Benzimidazoles
• **Metronidazole

Question 25

Benzimidazoles

Answer 25

• Can work but not used as much

Question 26

Metronidazole

Answer 26

• *banned in food producing animals
• Works great for Giardia treatment (ex. Flagyl: humans)
  o Can be used in dogs (Eradia oral suspension)
• Antimicrobial used for anaerobic infections