Lecture 18 11/9/23 Flashcards by Danika Boltz

What are the general characteristics of Chlamydia spp.?

-obligate intracellular
-parasites of epithelial cells
-susceptible to tetracycline
-dimorphic life cycle
-energy parasites/consume host ATP

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Which Chlamydia spp. is known for causing zoonotic infections?

C. psittaci

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Which Chlamydia spp. cause disease in humans?

-C. trachomatis (human chlamydiosis
-C. pneumonia

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What are the two life cycle stages of Chlamydia spp.?

-intracellular replicating form
-extracellular non-replicating form

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What are the characteristics of elementary bodies?

-infectious stage of Chlamydia spp.
-can survive outside the host

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What are the characteristics of C. psittaci?

-causes avian chlamydiosis
-BSL-3 pathogen
-zoonotic
-reportable

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What is the pathogenesis of C. psittaci?

-elementary bodies shed in carriers’ feces
-replicate in epithelial and phagocytic cells after inhalation
-cause septicemic, multi-organ infection

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Which lesions are associated with C. psittaci?

basophilic intracytoplasmic bacterial inclusions

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How are Chlamydia spp. diagnosed?

-microscopic detection
-culture in embryonated eggs, tissue, or animals
-serology
-PCR

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How are Chlamydia sp. treated?

tetracycline

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How are Chlamydia sp. controlled?

isolation and quarantine procedures

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What disease manifestations are caused by Chlamydia abortus in ruminants?

-placentitis
-abortion

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What disease manifestations are caused by Chlamydia pecorum?

-polyarthritis in lambs and calves
-sporadic bovine encephalomyelitis in young cattle

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What are the characteristics of Chlamydia felis?

-causes feline pneumonitis
-common signs are conjunctivitis and rhinitis

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What are the characteristics of Coxiella burnetii?

-causes Q fever
-obligate intracellular
-causes subclinical infection, abortion, and placentitis
-highly persistent in environment
-has resistant endospore-like form
-highly zoonotic

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How is Coxiella burnetii diagnosed?

-serology
-direct demonstration
-culture in cell lines
-PCR

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Which antimicrobials can be used to treat C. burnetii?

-tetracycline
-fluoroquinolones

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How can C. burnetii be controlled and prevented?

-hygiene
-education
-early diagnosis
-vaccination

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Which order Rickettsiales members are pathogens of dogs and cats?

-Ehrlichia canis
-E. chaffeensis
-E. ewingii
-Anaplasma phagocytophilum
-A. platys
-Neorickettsia helmintoeca
-N. risticii
-Rickettsia rickettsii

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What are the characteristics of Rickettsia?

-arthropod-transmitted
-parasites of blood cells or endothelial cells
-gram-neg. coccobacilli
-cause persistent infections
-obligate intracellular
-rodents/small mammals are reservoirs

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What are the two groups of Rickettsia?

-typhus group
-spotted fever group

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Which spotted fever group Rickettsia spp. is of most importance?

R. rickettsii

What are the characteristics of Rickettsia rickettsii infection?

-causes rocky mountain spotted fever
-organism invades and replicates in endothelial cells of smaller blood vessels
-causes progressive necrotizing vasculitis

What are the characteristics of Rickettsia felis?

-emerging infection in humans
-transmitted by cat fleas
-causes flea-borne spotted fever

How can Rickettsia spp. be diagnosed?

-direct detection -PCR -serology

Which antibiotics can be used against Rickettsia sp.?

-tetracycline -doxycycline -chloramphenicol -enrofloxacin

What are the characteristics of Piscirickettsia salmonis?

-causes piscirickettsiosis in farmed fish -antibiotic treatment commonly fails -vaccines available

What are the general characteristics of Anaplasmataceae?

-parasites of hematopoetic cells of vertebrates -transmitted by invertebrate hosts and vectors -can be zoonotic

Which genuses of Anaplasmataceae are of importance?

-Anaplasma -Ehrlichia -Neorickettsia

What are the characteristics of Anaplasma phagocytophilum?

-transmitted by Ixodes ticks -causes canine granulocytic ehrlichiosis -found in host neutrophils

What clinical sign of A. phagocytophilum is seen in dogs?

necrotizing small vessel vasculitis

What clinical signs of A. phagocytophilum is seen in horses?

-limb edema -icterus -ataxia

How is A. phagocytophilum diagnosed?

-direct staining/demonstration -PCR -SNAP test

Which antimicrobial can be used to treat A. phagocytophilum?

tetracycline

What are the characteristics of Anaplasma platys?

-causes infectious cyclic thrombocytopenia -infects platelets -often asymptomatic

How is A. platys diagnosed?

-direct detection -FA -PCR

How is A. platys treated?

doxycycline

What are the characteristics of Anaplasma marginale?

-causes anaplasmosis in ruminants -infects erythrocytes -causes icterus/jaundice -calves are more resistant than adults

How can A. marginale be diagnosed?

-direct stain -FA -PCR -ELISA -serology

How is A. marginale treated?

tetracycline

What are the characteristics of Ehrlichia canis?

-causes canine monocytic ehrlichiosis -infects monocytes and forms morulae -transmitted by R. sanguineus (brown dog tick) -acute and chronic phases -can cause pancytopenia in severe forms

How is E. canis diagnosed?

-IFA -snap test -PCR

Which antimicrobial is used to treat E. canis?

doxycycline

Which Ehrlichia species are spread by A. americanum ticks, and what diseases do they cause?

-E. ewingii: granulocytic ehrlichiosis -E. chaffeensis: human monocytic ehrlichiosis

What are the characteristics of Ehrlichia ruminantium?

-causes heart water disease -foreign and reportable -bacteria replicates in macrophages and endothelial cells -vectored by ticks

How is E. ruminantium diagnosed?

demonstration of colonies in the cytoplasm of capillary endothelial cells

Which antimicrobial can be used to treat E. ruminantium?

tetracycline

What are the characteristics of Neorickettsia risticii?

-causes potomac horse fever/equine monocytic ehrlichiosis -infects enterocytes and monocytes -leads to hemorrhagic enterocolitis

How is N. risticii diagnosed?

-based on clinical signs -PCR -direct detection

How is N. risticii treated and prevented?

-early diagnosis -tetracycline -vaccination

What are the characteristics of Neorickettsia helminthoeca?

-causes salmon poisoning in dogs -dogs eat tissue infected with flukes -infects monocytes and macrophages -causes lesions in intestines associated with the lymphoid tissues

How is N. helminthoeca diagnosed?

-detection of fluke eggs -PCR

How is N. helminthoeca treated?

-tetracycline -praziquantel