Preventative and Therapeutic Strategies Flashcards
PT01-03
start of PT01
would you give antimicrobials for a subsolar abscess?
no, drainage alone is usually curative
would you give antimicrobials to a horse with diarrhoea?
no
(not usually)
name 5 practical considerations when choosing an antimicrobial
- route of admin
- frequency of admin
- duration of therapy
- potential complications
- licensing
name a potential complication that can develop in horses with any antimicrobial
antimicrobial associated diarrhoea (AAD)
name the antimicrobial
bactericidal and time dependent;
++ for gram neg and pos, useless for anaerobic;
first line abx choice for horses, esp good for resp and urinary
Trimethoprim-sulphonamides (TMPS)
what is the main consideration/downside of TMPS
inactivated in purulent/necrotic tissue
what is the main complication of TMPS
fatal cardiac arrhythmias
name the only licensed oral antibiotic in horses
TMPS
(Equibactin, Trimadiazine)
name the antimicrobial
bactericidal, time dependent;
++ for gram pos, + for gram neg (NOT rods), ++ for most anaerobes;
injectable only;
often used in combo with Gentamicin for broad spectrum cover in hospital setting
penicillin (beta lactam)
name 3 possible complications of penicillin (beta lactam) in horses
- inadvertant IV injection (ataxia/seizure)
- hypersensitivity
- rapid IV admin (colic, loose faeces)
name the type of penicillin that should NOT be used in horses because it fails to reach MIC
Benthazine penicillin G
(Norocillin LA)
name the antimicrobial
bactericidal, concentration dependent;
+++ for gram neg;
injectable only;
commonly used in combo with penicillin for broad spectrum cover in hospital setting
Aminoglycosides
(Gentamicin)
what is the possible complication of aminoglycosides (Gentamicin) in horses
nephrotoxicity
(esp when dehydrated and used with NSAIDs)
name the antimicrobial
bactericidal, time dependent;
++ for gram neg, gram pos and anaerobes;
injectable only,
used for septic foals or following C&S;
NOT first-line usually, protected
cephalosporins
(Ceftiofur)
what is the possible complication of cephalosporins in horses
hypersensitivity
(urticaria, angioedema)
name the antimicrobial
bacteriostatic (cidal at high conc), both time and concentration dependent;
++ for gram neg and pos, + for anaerobes;
first line for intracellular oragnanisms: erlichial, rickettsial organisms, lawsonia, anaplasma
tetracyclines
(Oxytet, Doxy)
name 4 possible complications of tetracyclines in horses
- rapid IV injection (hypotension, collapse)
- oral ulceration
- nephrotoxicity (oxytet)
- incr risk of AAD
name the antimicrobial
bactericidal, concentration dependent;
+++ for gram neg, + for gram pos, no anaerobe;
protected, no licensed products;
used for renal disease and some pyogenic infections or for organisms resistant to other abx
fluoroquinolones
(Enrofloxacin)
name 2 possible complications of fluoroquinolones in horses
- oral ulceration
- arthropathy (foals)
name the antimicrobial
bacteriostatic (cidal at high conc), both conc and time dependent;
+++ for gram pos, + for gram neg and anaerobes;
not licensed for use in horses, canNOT be used in adult horses;
used in combo with Rifampin for treatment of Rhodococcus equi
Macrolides
(Azithromycin)
what is the complication of Macrolides in horses
fatal colitis if used in adults
name the antimicrobial
bactericidal and conc dependent;
+++ for gram pos, ++ for anaerobes, + for gram neg;
must be used in combo with other abx due to rapid development of resistances;
not licensed
Rifampin/Rifampicin
name the antimicrobial
bactericidal and conc dependent;
+++ for anaerobes, not for gram pos or neg;
not licensed in horses and NOT for food producing animals;
often used in combo with other abx if anaerobic coverage required (peritonitis)
Metronidazole
what is the potential complication of metronidazole in horses
anorexia
name the antimicrobial
bactericidal and conc dependent;
+++ for gram pos and neg and anaerobes;
not licensed, not for use in food producing animals, can cause aplastic anaemia in humans;
most common first line ocular choice for conjunctivitis
Chloramphenicol
what age must every horse have a passport and microchip by?
by 6 months
or by 31 Dec
what is the most important part of a horse passport
section IX, for human consumption or not
(impacts drugs able to be used)
start of PT02 - name the type of vaccination
induces an antigen specific immune response: dead antigen, live antigen, DNA expressing protein antigen
active vaccination
name 6 active vaccinations for horses
- equine influenza
- tetanus
- equine herpes virus
- equine viral arteritis
- strangles
- lawsonia
name the type of vaccination
administer pre-formed antibodies;
ex: tetanus antitoxin, plasma transfusion
passive vaccination
name the 3 UK brands of Equine Influenza vaccines
- Prequenza
- Equip
- Proteq
when should the 3 doses of equine influenza vaccines be given to horses
- from 5-6 months old
- 4-6 weeks
- 5 months
what is the booster interval for equine influenza vaccines?
1 year
name the tetanus vaccine for horses
two vaccines 1 month apart;
booster 2 years;
booster 6 weeks prior to parturition
tetanus toxoid
name the tetanus vaccine for horses
passive immunisation;
foals and unvaccinated horses;
remote site to vaccination
tetanus antitoxin
name the combined flu/tetanus vaccine for horses
Equilis Prequenza TE
name the disease horses should be vaccinated against
type 1: respiratory, abortion and neurological;
type 4: respiratory and occasionally abortion;
general protection for respiratory disease/racehorses: initial course 4 weeks apart, booster q6months;
breeding mares: vaccinate at 5,7 & 9 months to reduce abortion risk
Equine Herpes Virus
name the disease horses should be vaccinated against
initially 2 vaccines, 4wks apart;
booster every 2 months (3-6mo off-license);
reduces clinical signs/shedding;
serological ELISA test negative
Streptococcus equi subsp. equi
name the disease horses should be vaccinated against
2 doses 3-6wks apart from age of 9mo;
establishment of negative status of stallions prior to vax is important;
mostly used in competitions stallions traveling to endemic areas
Equine Viral Arteritis (EVA)
name the disease horses should be vaccinated against
live pig vaccine;
two doses (30mL) per rectum a month apart;
aim to complete a full course before risk period
Lawsonia
name the equine parasite
most pathogenic equine nematode;
encysted larvae in large colon over winter can lead to ‘en masse’ emergence late winter/early spring;
commonly affects horses <5years old and geriatric horses;
common cause of colic, diarrhoea, and weight loss
Cyathostomes
name 3 available diagnostic tests for parasites in horses
- faecal worm egg count (FWEC)
- Cyathostome ELISA (blood)
- tapeworm ELISA (saliva or blood)
name the anthelmintic regime for horses
encourages resistance;
not recommended now
interval dosing
name the anthelmintic regime for horses
anthelmintic dosing at specific times of year
ex: when first turned out, mid-season, autumn
strategic dosing
name the anthelmintic regime for horses
for adults only;
FWEC every 10-12wks during grazing season (spring to autumn),
no Tx if less than 250epg,
worm if more than 250 epg (ivermectin or pyrantel),
FECRT if more than 1000epg ;
treat for encysted redworm (moxidectin) +/- tapeworm (praziquantel) in december,
tapeworm saliva test 1-2 times yearly
targeted strategic
name 5 aspects of pasture management that can help reduce worm burden in horses
- minimum twice weekly removal of faeces from pasture
- avoid high stocking density/overgrazing
- avoid horses with high FECs
- avoid presence of young horses
- co-graze/alternate with other species
name 4 factors in anthelmentic resistance
- suboptimal dosing
- over-worming using interval programme
- use of only one drug class
- leaving no pasture refugia
when should routine worming be started in foals?
from 4-6wks of age
(single dose fenbendazole OR pyrantel)
name the wormer
macrocytic lactone;
commonly used to treat horses with high FWEC during summer;
resistance common in ascarids - avoid in youngstock
Ivermectin
name the wormer
macrocytic lactone;
often used yearly as part of targeted strategic worming programme +/- praziquantel;
reserve for encysted cyathostomes where possible (i.e. NOT in summer, save for winter)
Moxidectin
name the wormer
pyrimidine;
commonly used to treat horses with high FWEC during summer;
double dose for tapeworm
Pyrantel
name the wormer
benzimidazole;
5-day course licensed to treat encysted redworm (rarely used in adults now due to resistance);
useful in foals and for pinworm
Fenbendazole
(Panacur)
name the wormer
Pyrazinosiquinoline;
tapeworm only;
no OTC products available, off-license vet product only
Praziquantel
this is a disease that has appeared in a population for the first time, or that might have existed previously but is rapidly increasing in incidence or geographic range
emerging disease
name the notifiable disease
genus Orbivirus (morphologically similar to Bluetongue virus) - 9 serotypes;
biologically transmitted by Culicoides spp;
zebras shown to be a reservoir in South Africa;
Africal Horse Sickness
(African Horse Sickness virus)
name the form of African Horse Sickness
severe pyrexia 1-2d (40-41 C);
acute onset dyspnoea, coughing;
death within a few hours;
95% mortality;
fully susceptible animals (in UK)
per-acute / pulmonary form
name the form of African Horse Sickness
pyrexia 3-4d (39-41C);
subcutaneous oedema of head/neck;
resultant dyspnoea, dysphagia;
petechiation;
colic signs;
mortality 50%
acute / cardiac form
name the form of African Horse Sickness
combination of pulmonary and cardiac forms;
majority of cases;
70% mortality
mixed form
name the form of African Horse Sickness
donkeys, zebras, immune horses;
pyrexia (up to 40 C);
loss of appetite, mild dyspnoea, tachycardia, congested conjunctivae (but often subclinical)
horse sickness fever
name 6 differential diagnoses for African Horse Sickness
- anthrax
- equine infectious anaemia
- equine viral arteritis
- equine encephalosis
- piroplasmosis
- purpura haemorrhagica
name the notifiable disease
genus Flavivirus;
humans and horses are dead-end hosts;
spread by mosquitos;
travels to LNs then blood and causes brief low grade viraemia associated with transient fever;
other CS: ataxia, weakness, recumbency, muscle fasiculations, pyrexia, impaired vision;
dying birds often precede equine outbreaks
West Nile Fever
(West Nile virus)
name 7 differential diagnoses for West NIle Fever
- EEE
- WEE
- rabies
- EPM
- EHV-1
- verminous meningoencephalomyelitis
- hepatoencephalopathy
how to diagnose West Nile Fever
IgM ELISA on serology
name 3 treatments for West Nile Fever
- hyperimmune plasma
- supportive veterinary care
- euthanasia
name 4 risks to the UK for West Nile Fever
- migrating birds from WNV regions
- mosquito vectors within UK
- susceptible native birds
- ‘jet-setting’ mosquitoes
name the notifiable disease
lentivirus;
mechanical transmission by infected blood or blood products & vertical transmission;
pyrexia, inappetance, weight loss, signs of depression, anaemia, thrombocytopaenia, dependent oedema;
can be fatal;
all become carriers
Equine Infectious Anaemia (EIA)
(“Swamp Fever”)
name 2 ways to diagnose Equine Infectious Anaemia (“Swamp Fever”)
- Coggins test
- ELISA
name the toxic plant
alkaloids (taxines) block Na+ movement and depress myocardium;
causes collapse and sudden death;
possibly preceded by tremors and weakness
Yew
name the toxic plants
cardiac glycocide containing plants;
inhibit Na/K ATPase transport system (alter cardiac construction);
hyperkalaemia;
arrhythmias, sudden death
- Fox-glove (Digitalis purpurea)
- Oleander
name the toxic plant
tannins and their metabolites;
colic, haemorrhagic diarrhoea, haemoglobinuria, tachypnoea, tachycardia, sudden death;
treatment with fluid therapy and supplement electrolytes
acorns
name the toxic plants
chronic over-supplementation;
oxidative stress to RBCs causing Heinz body anaemia;
potential secondary haemoglobin-induced nephropathy;
fluid and electrolyte therapy
onion and garlic
name the toxin
mycotoxins produced by Aspergillus spp;
form in carbohydrates (grains) in field and storage;
cause liver disease, colic and haemorrhagic faeces;
can be fatal
aflatoxin
this disease is caused by toxin produced by endophyte (fungus) Neotyphodium lolii;
clinical signs of diffuse vestibulocerebellar disease (hypometria, ataxia, wide-based stance, intention-tremor, muscle tremors);
remove from pasture, provide new hay source
perenial ryegrass staggers
name 2 treatments for lead poisoning
- chelation therapy with calcium disodium EDTA
- Ca supplementation decr further GIT absorption
name the toxin
1st generation (warfarin) and 2nd generation (brodifacoum);
competitively inhibit vitamin K (required for clotting factors II, VII, IX, X);
haemorrhagic diathesis;
treatment with vitamin K1
coumarin derivatives
name the toxin
ionophore abx - transport ions across cell membranes, used as growth promoter and coccidiostat in cattle and poultry feed;
extremely toxic to horses, interferes with Na/K transport across cell membranes;
heart is main target;
signs vary from mild inappetance to sudden death (hypovolaemic shock)
monensin
