Lyme Borreliosis (LB) in dogs and cats
Many animals can have Lyme disease and show no signs. In dogs, the most common signs include fever, loss of appetite, painful or swollen joints, lameness that comes and goes, swollen lymph nodes, and lethargy. If Lyme disease is left untreated it can lead to damage in the kidneys, nervous system, and heart.
Causes: Lyme disease spirochete
Vector: ticks
Microbiology
Borrelia is invisible in bright-field microscopy. For visualization dark-field microscope is used. In fluids spirochetes are likely body tissues and motile. In liquids and semi-solid cultures spirochetes grow slowly. Cell organelles are present in protoplasmic cylinder. Wavelike motion is caused by structure variation of endoflagella. Outer membrane is enclosed by mucous and amorphous layer. Special receptors in borrelia bind components of complement factor H of host. Borrelia depends on necessary metabolic products and temperature of host. Borrelia belongs to family of Spirochaetaceae. Borrelia genus is heterogenous. Ticks feed on reservoir hosts then get infection. On rodents, squirrels, birds, moles, and lizards ticks feed. Ticks feed on large mammals after winter. Nymph molt into adults in autumn. Female leaves the host after insemination and releases eggs on ground.
 |
| What causes Lyme disease in dogs and cats |
Transmission
Infected tick bites vertebrate host and transmits bacterial
infection. Infected bitch does not have colostrum and milk. When dogs get
infection from ticks bite, borrelia is not traceable.
How to leave the tick
Borrelia is not travelled to vertebrate host during first 12
to 24 hours. To survive later in immunocompetent mammalian and avian host
spirochetes undergoes complex process. For penetration of spirochetes in midgut
of ticks OspC is essential protein. For protection of immune system tick
salivary protein 15( Salp 15) is necessary.
How to survive in vertebrate host
It is still under discussion that how to disseminate
borrelia in host of mammals. It is told that borrelia disseminate in blood by
body in one hypothesis. It is suggested that cellular, blood and soluble
immunologic components stimulate borrelia to travel by tissues and stay in
those tissues which consist of collagen in other hypothesis. In extracellular matrix
of infected dogs borrelia is located. Borrelia depends on N-acetyl-glucosamine.
In collagen enriched tissues tropism and diseased lesions present. On plasminogen
activator borrelia can bind and travels to host. Borrelia secretes screw like body into round shaped vesicle. Unsuitable
conditions minimize the metabolism of cell.
Effect of immune
response of host
LB is acute and chronic illness. Spirochetes not easily
released from immune system of host during infection. Phagocytosis process
helps to release spirochetes after infection. Infection causes increment of
antibodies and immunoglobulin (Ig). In synovial joints and perineurium T
lymphocytes present in massive amount. Cytokines ( eg. IL-10 and IL-4) play
role in process of pathogenesis.
LB in dogs
Not all dogs get this infection. Dogs get swelling, pain and
lameness when spirochetes spread in skin, joints and connective tissues. Synovial
fluids get increased in joints. Lethargy, peripherial edema, uremia, azotemia
and proteinuria associated in this disease. Asymptomatic encephalitis,
meningitis and mild peri neuritis are found in infected dogs. Cardiac arrhythmia
and myocarditis occur in dogs during infection but spirochetes in cardiac
tissues are not detected in early stages of infection. Anaplasma
Phagocytophilum can be found with LB.
LB in Cats
Tick bites on cat causes LB. Arthritis and meningitis
develop in infected cat. Cats are not as susceptible to this borrelial
infection as in dogs. Cats are not much sensitive to infection.
Diagnosis
Biopsy is performed to detect LB. In biopsy blood, tissue or
synovial fluid are taken. There are no high sensitivity or specificity of
bacterial culture to detect spirochetes. PCR is used to detect infection
because it gives faster result. ELISA test is performed to analyze immune
response of dogs and cats.
Treatment
Survival of Borrelia can be eliminated by antibiotics such
as tetracycline, amoxicillin, cephalosporines and azithromycin. Orally given
drug is doxycycline. Non steroidal drugs are used to treat pain. With
antibiotics glucocorticoids should be given. Vaccines are used to prevent dogs
and cats from infection.
Prevention
Dogs and cats should live in cleaned areas where ticks are not present. Inspect woods and grassy settings. Ask doctor to check dogs and cats whether they are ill or healthy.