Should be considered in any patient with clinical signs of<unk>  and a recent history of travel to the western United States or any other<unk>  endemic area.
Possible diagnostic samples:
Lymph node aspirate
Affected bubo should contain numerous organisms that can be evaluated microscopically and by culture.
Blood cultures
Organisms may be seen in blood smears if the patient is septicemic.
Blood smears taken from suspected bubonic<unk>  patients early in the course of illness are usually negative for bacteria by microscopic examination but may be positive by culture.
Sputum
Culture is possible from sputum of very ill pneumonic patients
However, blood is usually culture-positive at this time as well.
Bronchial/tracheal washing
May be taken from suspected pneumonic<unk>  patients
Not ideal for isolation of<unk> , since they often contain many other bacteria that can mask the presence of<unk> .
Affected bubo should contain numerous organisms that can be evaluated microscopically and by culture.
Organisms may be seen in blood smears if the patient is septicemic.
Blood smears taken from suspected bubonic<unk>  patients early in the course of illness are usually negative for bacteria by microscopic examination but may be positive by culture.
Culture is possible from sputum of very ill pneumonic patients
However, blood is usually culture-positive at this time as well.
May be taken from suspected pneumonic<unk>  patients
Not ideal for isolation of<unk> , since they often contain many other bacteria that can mask the presence of<unk> .
Gram, Wright, Giemsa, or Wayson's stained smears of peripheral blood, sputum, or lymph node specimen.
Visualization of bipolar-staining, ovoid, Gram-negative organisms with a "safety pin" appearance permits a rapid presumptive diagnosis of<unk> .
If cultures yield negative results, and<unk>  is still suspected, serologic testing is possible to confirm the diagnosis.
One serum specimen should be taken as early in the illness as possible, followed by a convalescent sample 4-6 weeks or more after disease onset.
One serum specimen should be taken as early in the illness as possible, followed by a convalescent sample 4-6 weeks or more after disease onset.
Plague
Psittacosis
Tinea
Anthrax 
Anthrax
Brucellosis 
Scabies
Q fever 