Lara C. Pullen, PhD

September 10, 2014

CHICAGO — The adenovirus was found in 14% of patients who underwent appendectomy, say researchers, who obtained results using polymerase chain reaction (PCR) over immunohistochemistry, which in the literature is reported to have a much lower rate at 0.23%.

David Lynch, MD, from the San Antonio Uniformed Services Health Education Consortium in Houston, Texas, presented the findings in a poster session here at the College of American Pathologists (CAP) 2014 meeting.

Approximately 36,000 young trainees undergo about 8 weeks of initial military training at Lackland Air Force Base in Texas each year. About a third develop an adenoviral upper respiratory tract infection during basic training.

"Do these guys have a cold a couple of weeks beforehand?" Dr. Lynch said to Medscape Medical News. "We are in the process of going through those records now."

In 2010, the military began to vaccinate for adenovirus. The vaccine prevents most illness caused by types 4 and 7 adenovirus. The vaccine is approved for military personnel and is recommended by the Department of Defence for trainees and other military recruits at high risk for infection.

More Vaccine, Less Appendicitis

Dr. Lynch's research sprang from the observation that trainees who were given the adenovirus vaccine had a reduced rate of appendicitis compared with those who had not been vaccinated.

There are 52 different types of adenovirus, and types 4 and 7 have been documented to cause severe respiratory illness outbreaks among military trainees.

Dr. Lynch used PCR to test for adenovirus in his study. His team analyzed 114 samples and found that 16 were positive for adenovirus. In contrast, immunohistochemistry was positive for only 1 sample.

Table. Adenovirus in Appendectomy Samples

Adenovirus Number
Type 4 13
Type B14 1
Other 2

 

"We figured that we were going to find more," Dr. Lynch said. "We just didn't know how much."

Adenovirus has been reported as a rare cause of appendicitis in children. The results of the current study raise the question of whether or not a cold may heighten the risk for appendicitis.

Philip Cagle, MD, editor-in-chief of Archives of Pathology and Laboratory Medicine, told Medscape Medical News that the research is interesting, but "from a practical point of view, if someone has appendicitis, you are going to take the appendix out."

The next question for Dr. Lynch is whether or not the adenovirus vaccine has actually reduced the rate of appendicitis.

Dr. Lynch and Dr. Cagle report no relevant financial relationships.

College of American Pathologists (CAP) 2014: Abstract 75. Presented September 8, 2014.

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