The parasite diagnosed by examining blood is:

• A. Anaplasma species
• B. Tritrichomonas species
• C. Dictyocaulus species
• D. Dioctophyma species

Answer: (A)

Examining a blood smear targets pathogens that are present in the bloodstream. Anaplasma species are intracellular organisms that reside inside blood cells and appear as morulae (clumps of bacteria) within leukocytes—or as inclusions in red blood cells depending on the species—on stained blood smears. This direct visualization makes blood smear examination a classic method to diagnose anaplasmosis.

The other organisms are identified from non-blood specimens: Tritrichomonas is typically detected in feces or mucosal samples by wet mounts, culture, or PCR; Dictyocaulus is a lungworm diagnosed via fecal Baermann testing or respiratory samples; Dioctophyma is a kidney worm diagnosed through urine analysis or imaging.