Infectious Disease Flashcards
If an equid with corona virus becomes acutely neurologic, what might be the cause?
Hyperammonemia may be due to increase from or absorption from the GI tract, and may contribute to the cause of death.
10.1111/jvim.12480
What kind of bacteria is Corynebacterium pseudotuberculosis?
C. pseudotuberculosis is a gram positive bacteria and causes extern and internal abscesses, was well ulcerative lymphangitis.
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What are the two biovars of Corynebacterium pseudotuberculosis?
Equis and Ovis.
The Equis biovar is nitrate (+) and the Ovis biovar is nitrate (-).
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Clostridium botulinum causes what in horses?
Botulism is characterized by progressive flaccid paresis and cranial nerve deficits (dysphagia, most common).
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What was most related to nonsurvival in horses with botulism? What are other factors?
Development of sustained recumbency at any point during hospitalization. Other factors related to nonsurvial were decreased rectal temp on arrival, cardiovascular compromise, dysphagia and abnormal respiratory effort.
10.1111/jvim.12502
What was the difference in animals that were colonized with M. haemolytica post-arrival colonization vs on arrival?
Recovery of M. haemolytica from 20% of cattle after arrival was higher than expected, as was the significant increase in prevalence over time. However, recovery of M. haemolytica in the second sample was not associated with increased morbidity or mortality, suggesting that post‐arrival colonization is more likely to be subclinical and may not be as great a concern for feedlot operators. In contrast, isolation of M. haemolytica on arrival was associated with a short‐term, significant increase in risk of clinical illness.
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What are possible vectors for Corynebacterium pseudotuberculosis? What possible insect vector was seen to be able to transmit?
Vectors in the horse are unknown, but speculations are: horse-to-horse contact, contact with pathogen-infested soil, insect vectors.
The bacterium can penetrate through skin, through abrasions.
The house fly, Musca domestica L. was seen to transmit.
House flies are not bloodsucking flies, but may transmit the bacterium through excoriated skin via mouthparts and tarsal exoskeleton. Further investigation is warranted to determine if house flies act as mechanical vectors or amplify the bacteria, and to determine if bacteria are carried on the external or in the internal organs.
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What is the pathogen for Lyme disease and what are some likely clinical signs? What is the vector?
Borrelia burgdorferi
Clinical signs in horses include shifting leg lameness, change in attitude, neurologic disease (eg, ataxia and weakness), skin lesions, uveitis, laminitis, lethargy, and hyperesthesia.
Ixodes scapularis is the vector.
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What does bovine corona virus cause in cattle?
Neonatal calves - diarrhea
Adults - winter dysentery
Both - respiratory illness
Also can be isolated in healthy animals
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What are characteristic clinical signs of Streptococcus equi ssp. equi?
Characteristic clinical signs include fever, accompanied by copious purulent nasal discharge, abscessation and rupture of lymph nodes in the head and neck region, followed by recovery over several weeks.
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In a study evaluating clinical, serologic and microbiologic factors related to unexpectedly mild disease severity in weanlings, which of these factors was of value in detecting exposure to S. equi?
immunologically naïve foals naturally exposed to an apparently fully virulent S. equi failed to exhibit classical clinical signs of strangles. This lack of clinical disease also was associated with incomplete serological reactivity to an enhanced serologic test for exposure to S. equi. The important aspect in relation to disease containment and control during outbreaks is that clinical signs alone may be insufficient to release horses from quarantine measures if they have clear exposure risks to known infected horses, and in particular with the well‐recognized risk of persistence as clinically silent carriers.
Serodiagnosis appears to be of value in detecting exposure to S. equi even in the absence of clinical signs.
10.1111/jvim.15037
What are some difficulties of diagnosing neuroborreliosis?
Documented clinical disease is rare, whereas subclinical infection with the causative organism appears to be widespread in horses living in endemic areas.
Less severe cases might be under‐reported because of the tremendous difficulty in confirming that clinical signs in the living horse are caused by Borrelia infection and not another cause. Lack of a reliable antemortem diagnostic test is a major obstacle.
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Since simultaneous testing of serum and CSF to calculate a CSF : serum ratio using the Lyme multiplex is not a reliable means of identifying equine neuroborreliosis cases, what criteria should be utilized for a presumptive diagnosis of neuroborreliosis in the horse?
First, the horse should have had possible exposure to Borrelia by residence in or travel to an endemic area.
Second, the horse should show neurologic signs for which other potential etiologies have been excluded by appropriate diagnostic testing.
These clinical signs should increase suspicion of neuroborreliosis: consistent with multifocal or diffuse nervous system involvement, often with cranial nerve involvement.
Abnormal CSF results, particularly those indicative of meningitis, with either a neutrophilic or lymphocytic pleocytosis, should increase suspicion for the disease.
Some horses with neuroborreliosis might have additional supportive evidence of nervous system infection, with either positive CSF PCR results or immunological test results suggestive of intrathecal antibody production.
10.1111/jvim.15067
In marine mammals with protozoan encephalitis, infection by 2 or more protozoa is linked with severity of disease. What might horses diagnosed with EPM, caused by Sarcocytis neurona, also be coinfected with?
Neospora hughesi or Toxoplasma gondii
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What has Theilers or idiopathic acute hepatitis been assoc. with in horses?
Been described in horses after treatment with equine serum products such as: tetanus antitoxin (most common), botulinum antitoxin, S. equi, pregnant mare serum, equine plasma.
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