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Infectious diseases of
horse
Druhově specifické zvláštnosti
při používání antibiotik:
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Peniciliny podané per os mohou narušit bakteriální
fermentaci v caeku a kolonu u dospělých zvířat
vedoucí k vážným poruchám trávení.
Tetracykliny mohou vyvolat těžké enterokolitidy u
koní vystavených stresu.
S výjimkou perorálního podání
erythromyciniumestolatu spolu s rifampicinem
hříbatům při rhodokokové pneumonii (Rhodococcus
equi) je třeba se vyvarovat použití makrolidů a
linkosamidů.
Také je třeba se vyvarovat podávání
fluorochinolonů - obecně u rychle rostoucích
zvířat - zejména hříbatům.
Bacterial infection in respiratory
system
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The upper RS
airsaculitis, acute
sinusitis
–
–
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strangles
–
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Streptococcus equi
subsp.zooepidemicus
Streptococcus equi subsp.equi
(vaccine)
The lower RS
bronchopneumonia acute
–
S.equi subsp.zooepidemicus
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bronchopneumonia chronic

S.equi subsp.zooepidemicus
Staphylococcus intermedius
E.coli,
Klebsiella spp.
Enterobacter spp.
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Salmonella spp.
Rhodococcus equi
Actinobacillus equuli
Pasteurella spp.
Fusobacterium
necroforum
Bacteroides spp.
Respiratory system - Viruses
Equine Rhinopneumonia (EHV-1 and 4)
Equine viral arteritis
Equine Influenza
Equine Rhinovirus
Equine Adenovirus
Equine Rhinopneumonia
 Etiologic
agents- EHV-4, EHV-1
 Virus Replication on mucosal surface
of respiratory system, establishment
of latency
 Rhinofaryngitis, tracheobronchitis,
fever
 Disease of young horses(up to 2
years), older animals – mild clinical
signs
Equine Rhinopneumonia
 Incubation
period 2-10 days
 Frequent secondary bacterial
infection
 EHV-1 biphasic fever
 EHV-1 – fulminant pneumonia in
transplacental infection (late
pregnancy)
Equine Adenoviruses
 Viruses
with low virulence
 Ocurrence in the age of 3 – 6 months
 Mostly subclinical
 Horeses are periodically reinfected
 Bacterial superinfections
Equine Adenoviruses
 Adenoviral
pneumonia
– Immunosupression
– Failure of passive transfer of antibodies
 Polysystemic
disease
– SCID (severe combined immunodeficiency)
in arabian horses
Equine Influenza
 Acute
febrile, highly contagious
disease
 Incubation period 1-3 days
 Dyspnoe, cough, fever, rhinitis,
conjunctivitis
THE ALIMENTARY SYSTEM

acute enteritis
–
–
–
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chronic enteritiS
–

Salmonella spp
Actinobacillus equuli
Clostridium perfringens type A cpb2+
L.intracellularis
acute peritonitis
–
–
–
–
enterobacteria
Bacteroides spp.
Bacteroides fragilis
Rhodococcus equi
–
Actinobacillus equuli
THE URINARY SYSTEM

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pyelonephritiS
Escherichia coli
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cystitis, uretritis
E.coli, P.mirabilis
Klebsiella spp., Enterobacter
Actinobacillus equuli
Streptococcus equi subsp.zooepidemicus
Pseudomonas aeruginosa
THE REPRODUCTIVE SYSTEM

endometritiS
– E.coli, K.pneumoniae
– Pseudomonas spp.
– S.equi subsp.zooepidemicus

orchitis, epidimitis, vesiculitis
– S.equi subsp.zooepidemicus

abortions
– Salmonella spp., S.Abortus equi
Urogenital system - Viruses
EHV-1
EHV-3
Equine viral arteritis
Equine infectious anemia
Equine virus abortion
 Virus
is ubiqituous in the horse
population, animals became infected
in the first year of age
 Latency in the ganglion trigeminale
 abortogennic strains (various level of
endotheliotropism)
Pathogenesis
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Epithelial cells
Leukocytes
Endothelial cells
In respiratory tract,
immune system
Pregnant uterus
Pathogenesis
Primary replication - epithelial cells of
respiratory tract
 Infection of endothelial cells of vessels
in nasal region, viremia associated with
monocytes and lymphocytes.
 Secondary replication in endothelial
cells of the uterus, CNS, testes,
endocrinne organs, infection of ganglion
trigeminale

Viremia
Establishment
of latency
(Lymphocytes)
Reactivation
Infection of the
uterus ...
Latency
(lymphocytes,
gangl. trigem.)
Equine Viral Arteritis
Virus
is ubiqitous
American isolates are more virulent
Incubation
period 3 – 14 days
Subclinical course
Clinical signs: fever, leukopenia, oedema
of scrotum and abdomen, conjunctivitis,
nasal and ocular discharge, abortion (10 –
60%)
Pathogenesis
Initial infection of bronchial macrophages
Following 48 h. regional lymph-nodes,
3. day viremia
Secondary replication in the walls of
medium and small vessels
Longlasting immunity follows natural
infection(up to 3 years). Protection
mediate by colostral antibodies last for 2 –
6 months, but interferes with vaccination.
Pathogenesis
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Respiratory route – primary and most
frequent way of infection, virus is shed for
7 – 14 dní
Infected semen - virus id transmitted
from persistently infected stallion to the
mare.
In stallions virus can persist in accessory
glands for the life . Perzistence is
testosteron dependent!
EHV-1 × EVA

EHV-1
– Virus reactivation preceedes abortion for
months
– Pulmonary eodema, transudate in the thoracic
cavity, petechias in myocardum of the foetus

EVA
– Abortion follows the disease of mare
– Foetus is partially autolysed
– Without specific changes
Equine exanthema coitale
 Occurs
in mares and stallions
(vesicular and pustular changes,
ulcerations)
 Virus replicationon the mucosa of
genital tract
 Infection is „self-limiting“ because of
the termosensitivity of the virus
 Ulceration are often contaminated by
bacterias
THE CENTRAL NERVOUS
SYSTEM

meningo-encefalitis(secondary
infection)
– S.equi subsp.zooepidemicus
– enterobacteria

Tetanus (Clostridium tetani)
CNS infection - Viruses
EHV-1 Myeloencefalopathy
Rabies
Bornas disease
EHV-1 Myeloencephalopathy


Virus strains displaying endotheliotropism
Ischemic changes due to infection of vascular
endothelium (vasculitis, thrombosis, petechias in
the CNS)
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Dysuria, cystitis (dysfunction of motor. neurons)

Infection of mare in 2/3 pregnancy

Higher incidence during winter and spring
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Paresis, ataxia of pelvic limbs
THE EYE

bacterial conjunctivitis
–
–
–
–
–
S.equi subsp.zooepidemicus
Pseudomonas aeruginosa
Staphylococcus intermedius
Moraxella equi
Listeria monocytogenes
– Acinetobacter spp.
– Corynebacterium spp.
– Bacillus spp.
SEPTICEMIA
 E.coli
 Salmonella
spp.
 Actinobacillus equuli
 S.equi subsp.zooepidemicus
 Staphylococcus intermedius
 CNS.
Equine infectious anemia
 Disease
of odd-toed animals
 Acute febrile disease with frequent
exacerbations (2-3 týdny)
 Virus is replicating in monocytes and
macrophages
 Virus transmission


blood sucking insect
needles (vaccination)
Pathogenesis
Antigenic variations – cause of frequent
exacerbations
 Immunocomplexes of free virus with
antibodies - glomerulonephritis,
 Virus is sensitizing erythrocytes and
thrombocytes to the action of
complement– anemia, petechias, icterus,
hearth failure, oedemas
 Splenomegalia
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THE SKIN
 folikulitis

a furunculosis
Staphylococcus intermedius
 lymphangitis
 S.equi subsp. equi
 Mycotic
infection
– Microsporum canis
– Trichophyton equinum(vaccines)
Equine Papillomaviruses
Virus type
Lesions
Localisation
EqPV-1
Papillomas
Hairy skin
EqPV-2
Papillomas
Genitals
BPV-1
Sarcoids
Hairy skin
BPV-2
Sarcoids
Hairy skin
Equine Papillomaviruses
 Typical
cytopathology on the skin
 Histological changes in the stratum
granulosum (inclusions)
 Virus id shed by contact and
desquamation
 Decontamination of the environment
is impossible
MUSCULOSKELETAL SYSTEM
 Septic
–
–
–
–
–
artritis
E.coli
Salmonella spp.
Actinobacillus equuli
Pseudomonas aeruginosa
S.equi sp.zooepidemicus
– Rhodococcus equi
– Staphylococcus intermedius
WOUNDS
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Traumatic
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Surgical wounds
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Clostridium perfringens
type A

enterobacteria

Actinobacillus equuli
Pseudomonas aeruginosa

S.equi sp.zooepidemicus
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Pseudomonas aeruginosa

S.equi
subsp.zooepidemicus

Staphylococcus aureus

S.intermedius
Nosocomial infection in
veterinary hospital
 multirezistant
strains
– Actinobacillus equuli
– Staphylococcus inetrmedius
– S. aureus (MRSA)
S. equi supsp. zooepidemicus