Microbiology Quiz: Anaplasma and Rickettsia

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Questions and Answers

What is the primary method for diagnosing Anaplasma platys infection?

PCR

Observation of morulae in platelets (correct)

Blood culture

Serology

Which of the following symptoms is NOT associated with Rickettsia rickettsii infection?

Thrombocytopenia (correct)

Neurologic signs

Lymphadenomegaly

Retinal hemorrhage

What is the recommended treatment for Anaplasma platys infection?

Clindamycin

Amoxicillin

Doxycycline (correct)

Azithromycin

Which tick species is NOT a known vector for Rickettsia rickettsii?

Ixodes scapularis (D) Signup and view all the answers

In which geographic regions is Rickettsia rickettsii commonly found?

North, Central, and South America (B) Signup and view all the answers

What is the primary mode of transmission for Tularemia?

Inoculation and skin/mucosal contact (A) Signup and view all the answers

Which antibiotic is considered a first-line treatment for Tularemia in humans?

Gentamicin (B) Signup and view all the answers

What is a common clinical sign of Tularemia in infected cats and dogs?

Splenomegaly (C) Signup and view all the answers

What is the initial classification of anemia caused by Canine Babesiosis?

Mild, normocytic, normochromic (A) Signup and view all the answers

What is the incubation period for Tularemia in dogs and cats?

1-5 days (C) Signup and view all the answers

Which diagnostic method is NOT recommended for Tularemia due to safety concerns?

Culture (A) Signup and view all the answers

Which treatment is likely to reduce morbidity and mortality for B. gibsoni?

Atovaquone and Azithromycin combination therapy (D) Signup and view all the answers

What is the significance of a negative slide exam in diagnosing Babesiosis?

It does not rule out the presence of the parasite. (A) Signup and view all the answers

Which diagnostic method requires careful interpretation due to varying species?

Nucleic acid-based detection (PCR) (A) Signup and view all the answers

Which dog breed has the highest reported cases of Babesiosis in the US?

Bully breed (B) Signup and view all the answers

What is the primary mode of transmission for Ehrlichiosis?

Tickborne (D) Signup and view all the answers

Which species of Ehrlichia is known to cause canine monocytic ehrlichiosis?

Ehrlichia canis (A) Signup and view all the answers

What is a common clinical sign associated with E.canis infection in dogs?

Uveitis (C) Signup and view all the answers

Which tick species is primarily responsible for transmitting Ehrlichia ewingii?

Amblyomma americanum (C) Signup and view all the answers

Which of the following is NOT a geographic region for E.canis spread?

Northern polar regions (A) Signup and view all the answers

The major clinical signs of E.ewingii infection include which of the following?

Fever and lethargy (C) Signup and view all the answers

Which of the following leukocytes does E.canis primarily infect?

Monocytes and macrophages (B) Signup and view all the answers

Which species is associated with human monocytic ehrlichiosis?

Ehrlichia chaffeensis (D) Signup and view all the answers

What is the most significant clinical sign associated with M.haemofelis infection in cats?

Severe hemolytic anemia (D) Signup and view all the answers

Which of the following hemotropic mycoplasmas is known for rarely being seen in blood films?

Candidatus Mycoplasma haemominutum (B) Signup and view all the answers

What is a common risk factor for cats infected with Candidatus M.haemominutum?

Outdoor exposure (A) Signup and view all the answers

What does a positive Coombs test indicate in the context of hemotropic mycoplasmas?

Presence of autoagglutination (C) Signup and view all the answers

Which organism is primarily responsible for chronic infections in cats that do not exhibit significant anemia?

Candidatus Mycoplasma haemominutum (B) Signup and view all the answers

What is the typical duration of anemia in cats infected with M.haemofelis?

18-30 days (C) Signup and view all the answers

Which tick species is known for the experimental transmission of M.haemocanis in dogs?

Rhipicephalus sanguineus (D) Signup and view all the answers

What percentage of M.haemocanis infected dogs may experience rapidly progressive anemia?

60-70% (A) Signup and view all the answers

What is the typical clinical manifestation timeframe for acute disease after infection with Ewingii?

2-3 weeks (A) Signup and view all the answers

Which of the following is a key diagnostic method for canine granulocytic anaplasmosis?

Detection of morulae within granulocytes (A) Signup and view all the answers

Which species is responsible for canine thrombocytotropic anaplasmosis?

Anaplasma platys (D) Signup and view all the answers

What is the primary treatment for infections caused by Ewingii?

Doxycycline (D) Signup and view all the answers

How does Anaplasma phagocytophilum primarily affect the host's blood cells?

Leads to thrombocytopenia (D) Signup and view all the answers

What key feature distinguishes Anaplasma phagocytophilum from Anaplasma platys in terms of clinical signs?

Anaplasma phagocytophilum often results in polyarthritis (C) Signup and view all the answers

What is the role of dogs in relation to Anaplasma phagocytophilum concerning human health?

They are sentinels for human granulocytic anaplasmosis (A) Signup and view all the answers

Which of the following is a common serological finding in Ewingii infections before seroconversion occurs?

Morulae in blood smears (A) Signup and view all the answers

Study Notes

Blood Borne Infections

Objectives include understanding transmission routes, prevention, cytology findings, clinical syndromes, diagnostic limitations, and treatment recommendations for various diseases.
The presentation outlines different transmission modes for bloodborne infections, specifically focusing on tick-borne and eating-the-host transmissions, listing diseases such as Ehrlichiosis, Anaplasmosis, Rickettsiosis, Cytauxzoonosis, Mycoplasmosis, Babesiosis, and Tularemia.
Greene's Infectious Diseases of the Dog and Cat, 5th edition (chapters 44, 45, 46, 58, 74, 97, 98) is recommended for further reading. These chapters are accessible online via the UGA Library.

Ehrlichiosis

Three species (Ehrlichia canis, ewingii, chaffeensis) are intracellular, gram-negative bacteria.
They are part of the Anaplasmataceae family; include Anaplasma platys and Anaplasma phagocytophilum, with E. canis causing canine monocytic ehrlichiosis.
Geographic distribution: E. canis is worldwide but common in tropical/subtropical areas. E. ewingii is prevalent in south-central and southeastern USA. E. chaffeensis is common in southern and south-central USA and Africa
Transmission is tick-borne (Rhipicephalus sanguineus: Brown Dog tick, Amblyomma americanum: Lone Star tick), and Amblyomma maculatum: Gulf Coast tick.
Clinical signs in dogs include fever, lethargy, anorexia, weight loss, skin/mucosal hemorrhages, lymphadenopathy, splenomegaly, uveitis. Cats present with similar symptoms plus joint pain, hyperesthesia, and polyarthritis.
Form morulae within phagocytes of circulating leukocytes (e.g., E. canis in monocytes, macrophages, and lymphocytes;CMD, and E. ewingii in granulocytes, E chaffeensis, human monocytic ehrllichiosis).
Acute, subclinical, and chronic phases of ehrlichiosis are covered, including thrombocytopenia commonly seen 1-4 weeks after infection (more than 90% of acute cases).
Diagnostic methods for Ehrlichiosis include IFA (gold standard), detecting antibodies 7-28 days after infection, ELISA (e.g., SNAP 4Dx Plus, IDEXX), Western immunoblotting (primarily research), and PCR (whole blood) for acute infections. PCR and serology should be combined for the best outcome
Treatments: Doxycycline/minocycline, focusing on high blood, tissue, and intracellular concentration (10 mg/kg/d PO x 21-28 days); alternative doses/regimens are noted (5mg/kg q12 x 14 days). Supportive care is also essential.

Anaplasmosis

Two species: Anaplasma platys (canine thrombocytotropic anaplasmosis) and Anaplasma phagocytophilum (canine granulocytic anaplasmosis).
Obligate intracellular, gram-negative pleomorphic bacteria lacking a cell wall. Part of the Anaplasmataceae family
Geographic distribution: A. phagocytophilum in upper midwestern, northeastern, and western US states, and A. platys throughout the Americas.
Transmission occurs via tick bites (Ixodes ricinus-persulcatus complex—Ixodes scapularis, I. pacificus - Western Blacklegged tick; Rhipicephalus sanguineus—Brown Dog tick).
Clinical signs in A. phagocytophilum infections include fever, lethargy, inappetence, lameness (polyarthritis). A. platys may cause fever, lethargy, and potential effects on the platelet count.
A. phagocytophilum infects humans, causing granulocytic anaplasmosis while dogs are sentinels, meaning they can be a warning indicator of possible issues in the animal population or in surrounding areas
Diagnosis involves identification of morulae within granulocytes (as early as 4 days post-inoculation), and PCR for acute infections without morulae, as well serological tests (titers)/ELISA. Acute and convalescent titers are needed to confirm the infection (4-fold change).
Treatment: Doxycycline 5mg/kg PO q12 x 28 days or 14 days, depending on treatment. Clinical improvement within 24-48 hours of treatment, and platelet counts normalize within 2-14 days.

Rickettsia rickettsii

Rickettsia rickettsii causes Rocky Mountain Spotted Fever (RMSF), a gram-negative, obligate intracellular bacterium infecting endothelial cells. It affects humans and dogs, part of the Rickettsiaceae family.
Widely distributed in North, Central, and South America.
Transmission: ticks (Dermacentor variabilis (American dog tick), andersoni (Rocky Mountain wood tick), Amblyomma americanum (lone star tick), cajennense sensu lato (Cayenne tick), aureolatum (yellow dog tick), Rhipicephalus sanguineus (brown dog tick)).
Clinical signs: acute febrile illness, vasculitis, fever, vomiting, ocular signs, lymphadenomegaly, splenomegaly, peripheral edema, cutaneous hyperemia, necrosis, polyarthritis and neurological signs. Young and purebred dogs (e.g., English Springer Spaniels with PFK deficiency) and GSDS may be overrepresented as patients.
Diagnosis involves acute CS + PCR or IHC, serological conversion (fourfold change in acute and convalescent titers), and PCR (especially acute phase).
Treatment: Doxycycline(5 mg/kg PO q12 * 7-14 days), starting before the diagnosis is confirmed. Rapid clinical response typically observed within 24-48 hours.

Cytauxzoonosis

A hematoprotozoal parasite (Cytauxzoon felis) affecting domestic cats.
Two forms: Nonerythrocytic (schizont) and erythrocytic (piroplasm)
Bobcats serve as a reservoir. Amblyomma americanum (lone star tick) and Dermacentor variabilis (American dog tick) are vectors.
Geographic distribution is in the Midwest, south-central, south-eastern, and mid-Atlantic states with expansion with the range of Amblyomma Americanum.
Clinical signs include a 1-3 weeks rapid progressive, clinical course frequently resulting in death (within days); fever (up to 107º F), icterus, pallor, lymphadenomegaly, splenomegaly, and seizures are common.
Diagnosis relies on identifying Cytauxzoon felis piroplasms in red blood cells ("signet rings") via blood smears. Epicellular cocci/rods/rings, and PCR are additional diagnostic tools.
Treatment involves supportive care, IV fluids, red blood cell transfusions (for severe anemia), and immidocarb which may be less efficient or has fewer beneficial outcomes. Atovaquone and azithromycin are more effective. Careful attention is needed if the patient is experiencing DIC. Prevent tick bites as there are no vaccines for Cytauxzoonosis

Hemotropic Mycoplasmas

Gram-negative, obligate epierythrocytic bacteria; wall-less bacteria, non-acid-fast. Formerly called Haemobartonella and Eperythrozoon.
Geographic distribution is worldwide.
Transmission in dogs is via ticks (Rhipicephalus sanguineus), other arthropods (fleas or mosquitoes) and biting or aggressive interactions and also vertical transmission.
Clinical signs in cats include fever, lethargy, anorexia, weakness, pallor, and dehydration.
Diagnosis in cats is with blood films showing small, dark, blue-staining rods or cocci and possibly ring-forms and loss of normal RBC appearance/shape. Diagnosis in dogs involves cytologic examination of stained blood smears (50%), PCR, and serological testing.
Treatment includes antibiotics like doxycycline (for M. haemocanis) in both cats and dogs and supportive care is critical in cases of severe anemia.

Canine Babesiosis

Various intraerythrocytic protozoan parasites (Babesiaspp.) infecting dogs.
Species include Babesia canis (vogeli), rossi, vogeli, gibsoni, conradae, vulpes, negevi sp Nov. More species are unnamed.
Babesia felis*, canis, gibsoni, cati, and lengau and unnamed species are in cats
Worldwide distribution; species-specific geographic distribution.
Transmission and diagnosis involve ticks (like Rhipicephalus sanguineus) and dog fighting wounds (Haemaphysalis spp., Rhipicephalus sanguineus) and transplacental transmission. Stained slides for Babesia species and convalescent titers are part of the testing protocol. PCR is also useful.
Treatment: Imidocarb dipropionate is used in milder cases, while atovaquone + azithromycin, or clindamycin/metronidazole/doxycycline combinations are used in severe or persistent cases. At least 3 months of treatment is common.

Tularemia

Francisella tularensis, a gram-negative coccobacillus (facultative intracellular bacteria, aerobic), is responsible for tularemia.
Transmission includes inoculation, skin/mucosal contact, aerosols, inhalation, ingestion, and vector transmission.
Vectors include ticks (e.g., Dermacenter andrsoni, variabilis) and biting flies (Western USA).
Geographic distribution is in Northern Hemisphere (between 30 and 71 degrees latitude) with virulent strains prevalent in the USA.
Clinical signs: fever, lethargy, inappetence, lymphadenopathy, skin abscesses, splenomegaly, hepatomegaly, and GI signs. Young adult dogs and cats are susceptible. Tularemia is a reportable disease in the USA
Incubation lasts 1-5 days in dogs/cats.
Diagnosis involves thrombocytopenia, and culture/PCR/serological tests.
Treatment in humans involves parenteral aminoglycosides like gentamicin or fluoroquinolones. For animals use gentamicin 5-8 mg/kg IV, IM or SC q24 x 14 days or doxycycline 5mg/kg PO q12 x 2-3 weeks or marbofloxacin 2.75-5.5 mg/kg PO x 2-3wks for initial 72 hours and minimize caregiver exposure.

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Description

Test your knowledge on the diagnosis, symptoms, and treatment of Anaplasma platys and Rickettsia rickettsii infections. This quiz covers the diagnosis methods, associated symptoms, and tick vectors for these pathogens, providing insights into their geographic prevalence. Perfect for students studying microbiology or veterinary science.