A woman who recently came home from a tropical vacation now has abdominal pain and diarrhea. Her blood test results how an elevated eosinophil level. Which of the following organisms is most likely to cause her illness?

A. Bacteria
B. Worm
C. Virus
D. Fungus

I think it's C but want to make sure. I'm torn between A and C.

According to the Merck Manuals on eosinophilia,

"...Causes and associated disorders are myriad but often represent an allergic reaction or parasitic infection...."

Draw your own conclusions.

Hint: the woman returned from a tropical vacation.

To determine which organism is most likely to cause the woman's illness, we need to analyze the given information.

First, the woman recently came home from a tropical vacation. This information is crucial because it suggests a possible exposure to organisms that are more commonly found in tropical regions.

Next, the woman is experiencing abdominal pain and diarrhea. These symptoms can be indicative of various gastrointestinal infections.

Finally, the blood test results show an elevated eosinophil level. Eosinophils are a type of white blood cell that are often associated with allergic reactions and certain infections, particularly those caused by parasites.

Given these facts, it is reasonable to assume that a worm, represented by option B, is the most likely organism to cause the woman's illness. Worm infections, also known as helminth infections, are common in tropical regions and can result in gastrointestinal symptoms such as abdominal pain and diarrhea. The presence of elevated eosinophil levels further supports the possibility of a parasitic infection.

Therefore, the correct answer is B. A worm is most likely to cause the woman's illness.