Micro: bacteria, virus, and protozoan blood borne infections

What species are you thinking is you see:

gram negative, bacillus (rods), catalase and oxidase negative

Bartonella

What pathogen and type?

cat stratch disease/fever

you see enlarged lymph nodes, low grade fever, malaise, and potential bacillary angiomatosis

more common in the immunocompromised (not the immunocompentent)

bartonella henselae

bacteria

What pathogen and type?

transmission through a body louse that causes trench fever

you see high fevers, rash, HA, back and leg pain

there is a 5 day interval between febrile episodes

bartonella quintana

bacteria

What pathogen and type?

seen in Peru, Ecuador, Colombia

caused by a sandfly; causes Oroya fever/ Carrion disease

clinical features: massive anemia, myalgia, and arthralgia

multiplies within the erythrocyte cytoplasm

Bartonella bacilliformis

bacteria

How do we diagnose suspected bartonella bacilliformis infection?

blood culture or peripheral smear

How do we diagnose suspected bartonella quintana?

PCR, culture of lymph nodes, aspirate or blood, serology

How do we diagnose suspected bartonella henselae infection?

clinical signs, PCR, and cultures (can take up to 21 days)

What species do you think of when you see spirochetes (corkscrews) that are viewed under dark field microscopy or with Giemsa stain (no gram stain)

Borrelia species

What pathogen and type?

seen in the Northeast and upper midwest and certain parts of Europe

vector: Ixodes (deer) tick bite

lyme disease: 3 stages from the erythema migrans (bullseye rash) to facial palsy, HA, lyme carditis, and lyme arthritis, to the last stage with lyme encephalopathy and acrodermatits chronica atrophicans

Borrelia burgdorferi

bacteria

How do we diagnose a suspected borrelia burgdorferi infection?

clinical features, dark-field microscopy of wet mound, and serology (ELISA, immunoblot)

What pathogen and type?

First in Japan then Conneticut and Russia

bite from Ixodes tick

hard tick relapsing fever

fever, chills, HA, myalgia, fatigue, neurological disease in the immunocompromised

Borrelia miyamotoi, bacteria

How do we diagnose a suspected borrelia miyamotoi infection?

PCR and serology (Western blot)

What pathogen and type?

seen in northeast and midwest USA

deer/ixodes tick

causes flu-like illness with fever, chills, fatigue, myalgia, hemolytic anemia

Causes Babesiosis

Babesia microti, protozoan

How do we diagnose a suspected babesia microti infection?

blood smear with giemsa stain

you see the classic tetrad pattern (Maltese cross) in RBCs

Expain the life cycle of babesia microti

the tick bites a human and introduces sporozoites into the host, then they enter the RBCs and replicate, this multiplication leads to clinical manefestations (human to human transmission can oddur through blood transfusion)

Plasmodium species causes what disease?

malaria

Which plasmodium?

fever pattern: irregular

does not create hypnozoites in the liver

is the most severe form of malaria

can get blackwater fever and cerebral malaria

Plasmodium falciparum

Which plasmodium?

fever: quotidian (every 24 hours)

does not form hypnozoites in the liver

typically infects monkeys (Rarely infects humans)

Plasmodium knowlesi

Which plasmodium?

fever: tertian (Every 48 hours)

forms hypnozoites in the liver

Plasmodium vivax and Plasmodium ovale

Which plasmodium is capable of forming hyponozoites in the liver?

Plasmodium vivax and Plasmodium ovale

Which plasmodium?

fever: quartan (every 72 hours)

has a long incubation

does not form hypnozoites in the liver

Plasmodium malariae

What pathogen and type?

worldwide but more prevalent in warm climates

tramsission: house cats, contaminated meats or shellfish, transplacental or organ transplant (both rare)

can cause TORCH infections (passed from mother to fetus)

• triad: chorioretinitis, hydrocephalus, and intracranial calcifications

Toxoplasma gondii, protozoan

How do we diagnose a supsected toxoplasma gondii infection?

elevated Ab titer

ring-enhancing lesions on heat CT/MRI

What pathogen and type?

central and south america, africa, and the middle east

vector: sandfly

blood-borne flagellate, obligate intracellular

Leishmania spp., protozoan

Explain the life cycle of leishmania

an adult salndfly delivers promastigote stage (flagellated form) to humans, then the promastigotes invade the macrophages, then they become the non-motile amastigotes and multiply in the macrophages

How do we diagnose a suspected infection of leishmania?

microscopy of skin scrapings/biopsy from ulcer base (you see macrohpages with amastigotes)

There are 3 types of Leishmania clinical forms:

describe the cutaneous form

the bite results in ulcerating lesion that leads to scarring

There are 3 types of Leishmania clinical forms:

describe the ,ucocutaneous form

mucous membrane involvement

initial sign: dermal ulcer that heals quickly

months to years later: you can get ulcers in mouth and nose

There are 3 types of Leishmania clinical forms:

describe the visceral (Kala-azar) form

you see a spiking fever, reticuloendothelial system cells, hepatosplenomegaly

diagnose with liver and spleen biopsy

fatal if untreated

What pathogen and type?

seen in Mexico, central america, south america, and south texas

transmission: Reduviid (kissing) bug

disease: Chagas disease

Trypanosoma cruzi, a protozoan parasite

What pathogen and type?

clinical features: Chagoma: hardened red skin rash at site of entry; romana sign: rash and edema around the eyes

common sx: mild fever ,malaise, and lymphadenopathy

Trypanosoma cruzi, a protozoan parasite causing Chagas disease.

What pathogen do we see the classic triad of: megaesophagus, megacolon, and dilated cardiomyopathy

thrives in poor housing conditions/ rural areas

Trypanosoma cruzi, a protozoan parasite causing Chagas disease.

What pathogen and type?

seen in Africa

vector: tsetse fly

causes African sleeping sickness (African trypanosomiasis

first manefestations: hard, red painful skin ulcer

systemic: relasping fever, HA, dizziness

neurologic: lethargy, behavioral changes, ataxia, slurred speech, coma, death

Trypanosoma brucei

protozoan

trypanosoma brucei:

which subtype goes with West Africa and which one goes with East Africa? which one is more severe?

west africa: T. gambiense

east africa: T. rhodesiense (more severe)

How do we diagnose a suspected infection of trypanosoma brucei?

giemsa stain of blood smear or microscopy of lymph nose aspirate

must examine CSF to determine CNS involvement

What pathogen and type?

flaviviridae family

Aedes mosquito

Peurto rico, US virgin islands, hawaii

transmission: perinatal, gestational, sexual, and blood-born

Zika

virus

What infection is assocaited with higher incidence of Guillain-Barre syndrome?

Zika virus infection (also causes microcephaly in babies)

How do we diagnose a suspected zika virus infection?

clinical (Travel history), RT-PCR, ELISA, serology

What pathogen and type?

has 2 major surface glycoproteins, one is a spike protein that binds to the ACE2 receptor of host cells

clinical features: cough, fever, difficulty breathing, acute respiratory distress syndrome, cytokine storm, diffuse alveolar wall thickening

SARS-CoV-2 virus

How do we diagnose a suspected SAR-coV-2 virus infection?

antigen test and PCR