parasite control (mallicote) Flashcards
1
Q
Goal for young horses
A
limit parasite burden until young horses develop their immunity
2
Q
goal for adult horses
A
minimize disase without inducing a resistance to parasiticides
3
Q
Major internal parasites
A
-
small strongyles (Cyathostomes)
- seasonally transmitted
- winter in FL, summer in north
- Large strongyles
- Anoplocephala perfoliata (Tapeworms)
- Ascarids - Parascaris equorum
- year round infection of young horses
4
Q
Minor internal parasites
A
- Gastrophilus intestinalis (Bots)
- Habronema muscae, Draschia megastoma (stomach worms)
- Oxyuris equi (Pinworms)
- Strongyles westeri (Threadworms)
- Dictyocaulus arnfieldi (lungworms)
5
Q
Small strongyles / Cyathostomes
A
- Most important parasite to manage in adult horses
- Significant concern for resistance in these populations
- prepatent period - minimum 5 weeks
- relatively short period of time
6
Q
Small strongyles / Cyathostomes
life cycle issues
A
- larvae migrate in cecum/colon walls for 4-6 weeks
- may encyst for months to years
- mature and encysted cyathostomes are not significant in causing disease if moderate numbers
7
Q
small strongyles
progression
A
emergence of larvae =>
Intense inflammation =>
hemorrhage and edema of cecum and colon =>
Colic and diarrhea
8
Q
Large strongyles
A
- migrate through abdominal tissues
- liver, pancreas, arteries
- LIve in lume of gut
- long prepatent period (6 months)
- don’t have to treat very often
- CS
- colic, poor growth, weight loss
*we rarely see this parasite (since advent of ivermectin)
9
Q
Parascaris equorum (roundworms)
A
- adult horses develop immunity
- eggs persist in environment for years
- deadly for young foals
*only parasite that will be in the small intestine of the horse (others in colon….I think)
10
Q
Parascaris equorum (roundworms)
progression
A
- parasite lives in small intestine =>
- lymphatics =>
- lungs =>
- pharynx =>
- small intestine
11
Q
Parascaris equorum (roundworm)
days to reenter SI
A
28 days
12
Q
Parascaris equorum (roundworms)
days to produce eggs
A
72-80 days
-before you see eggs in fecal
13
Q
clinical signs of ascarid infection
A
- coughing
- diarrhea, colic
- pot belly
- rough hair coat
- weight loss
- can’t be diagnosed prior to 80-90 days of infection by fecal float
14
Q
ascarid resistance
A
*
15
Q
Control of ascarids
A
- control fecal egg count reduction efficacy test
- deworm at 60 days of age (exposure, possibility of ascarids in spite of neg fecal)
- deworm q 60 days (ivermectin) until 8-12 months of age or
- q 30 days (pyrantel/benzimidizole group) until 8-12 months of age
16
Q
Anoplocephala perfoliata (Tapeworms)
A
- live at narrow ileo-cecal valve
- spasmodic colic
- intussusceptions
- ileal impactions
- praziquantel
- 1 mg/kg-2.5 mg/kg
- pyrantel
- 13.2 mg/kg
*don’t really see resistance to praziquantel
*intermittantly shed so may not see them on a fecal even if they are infected
17
Q
Tapeworms
foal deworming
adult deworming
A
- Foals
- deworm prior to weaning
- Adults
- deworm 1-2 times/year
18
Q
Gastrophilus intestinalis (botfiles)
A
- little yellow eggs on legs
- treatment
- remove bots from legs
- Ivermectin or Moxidectin
- cause very few clinical signs
- very susceptible to ivermectin
19
Q
Habronema, Draschia spp (stomach worms)
A
- transmitted by stable flies
- no significant internal damage
- cutaneous infections => granulomas (sometimes bx)
- eyes, sheath, ventral midline
- treat with ivermectin
- sometimes plus steroids
*if in their normal spot don’t cause lots of clinical dz
20
Q
Oxyuris equi (pinworms)
A
- live in small colon
- female cements eggs to skin of anus
- prepatent period 3.5-5 months
- diagnosis probs
- usually found as adult worms
- difficult to find on fecal float
*tape test around anus good for this
*some resistance to ivermectin…?
21
Q
DDX for tail rubbing
A
- pin worms
- dirty gelding sheath
- dirty mare udders
22
Q
strongyloides westeri (threadworms)
A
- cause of diarrhea in foals
- 5 days - 4 months
- Infectio via milk
- stress of foaling induces larval activation in dam
- Parasite resides in SI
- Immunity quickly developed (4-5 months)
- prepatent period 5-7 days
*imp DDX for diarrhea in foals
23
Q
Strongyloides westeri
treatment
A
- treat mares in late gestation/foaling
- macrocyclic lactones
- treat foals PRN
24
Q
Lungworms (Dictyocaulus arnfeldi)
A
-
donkeys the problem
- can harbor with no CS
- Horses exposed parasite via donkeys
- cough
- decreased performance
- Treat with ivermectin
- DX: BAL (eosinophilia or parasites), Fecal (Baermans float-settle to bottom)
25
Parasites of concern for the adult horse
* **Small & Large Strongyles**
* **Tapeworms**
* Gastrophilus
* Oxyuris
26
Parasites of concern for the juvenile horse
* Ascarids-impaction
* Strongyloides
* Small and Large Strongyles
27
Refugia
* want to maintain a population of parasites that has not been exposed to parasiticides
* Wild type parasites that have not be exposed to anthelmintic pressures (lack resistance genes)
* Minimal deworming favors survival of 'wild type' parasites
28
New Paradigm
* Resistance as emerging problem
* use fecal egg reduction testint to determine to effective antihelmintics
* treat horses with high FEC
* treat during peak transmission season
29
Fecal egg counts
* Quantitation of strongyle burden
* \< 200 epg (don't treat)
* 200-500 epg (may not treat)
* \> 500 epg (treat)
30
Fecal egg count reduction test
[(pre-treatment EPG) - (post-treatment EPG)] X 100
samples pre and 10-14 days post deworming
31
FECRT interpretation
* \> 90% for pyrantel and BNZ = good
* 80-90% for Pyrantel and BNZ = suspicious
* \< 80% for Pyrantel and BNZ = resistance
* macrocyclic lactones \< 98% = resistance
32
deworming
new paradigm
* south: (85 deg F - death to larvae)
* north: (\<45 F - will not support hatching)
33
Egg reappearance Period
* **expected egg reappearance period**
* ****interval between treatment and resumption of FEC \> 200 EPG
* Benzimidazoles - 4 weeks
* Pyrantel salts - 4 weeks
* Ivermectin - 8 weeks
* Moxidectin - 12 weeks
34
Take home message
* Preserve refugia: deworming least often as possible
* Deworm individuals instead of populations
* keep season in mind
35
Normal foal behavoir
1-2-3 rule
* sternal recumbency within 2 min of birth
* suckle reflex within 30 minutes
* standing within 60 minutes
* nursing from mare within 120 minutes
\***1-2-3 rule =\> 1 hour to stand; 2 hours to nurse; 3 hours to pass placenta**
36
Physical exam
* first 12-24 hours of life
* systematic
* record
* monitor trends
* detect slow changes
37
foal temps
* normal 99-102 deg F
* hypothermia common in sick neonates
* unable to adequately cool in very hot climates
* FL
38
Cardiac auscultation
* HR immediately post partum 40-80 bpm
* inc to 100-120
* 80-100 bpm during week 1
* murmurs
* PDA
* innocent flow mumurs (not cont, discrete, etc)
* ventricular septal defect
39
Foal mucus membranes
* color, injected (red), yellow, abrasions, evidence of sepsis
* also look at conjuctiva (injected vessels consistent with dystocia)
40
Respiratory rate/Auscultation
* crackles usually last several hours from birth
* transition from fluid filld to air filled lung
* inc in minute ventilation
* rate x tidal volume
* 80 - 30 breaths/min
* inspiratory and expiratory crackles
* dependent atelectasis
* normal 30-40 breaths/min
41
Umbilical care
* very important
* dilute chlorahex
* dip several times per day until dry
* No tincture of iodine: toxic to tissues
42
Enema
* Give in first few hours of life
* fleet enemas
* warm soapy water ok too
* ivory
* Do NOT give repeat enemas
43
Colostrum
* critical for foal to receive to provide antibodies
* foals need about 2 liters in first 24 hours
* first 2 hours life most critical
* gut closure
44
Immunoglobulin (IgG)
* Measure IgG at 12-24 hours of age (Snap test)
* if \< 800 **consider** transfusion
* if \< 400 **definite** transfusion
\*colostrum replacers NOT USEFUL
45
Vaccinations and antimicrobials
Newborns
* Tetanus antitoxin
* if mare was not properly vaccinated
* Routine antimicrobials not necessary
* Non-observed birth - risk of sepsis - ok to give ABX
* History of problems on the farm - ok to give ABX
46
Newborn Check list
* 1-2-3 rule
* Dip umbilicus
* give enema
* DVM exam \< 24 hours old
* IgG check between 8-24 hrs of age
* +/- vaccinate/antimicrobials
