Answer to Case 715

 Answer to the Parasite Case of the Week 715: Cockroach ootheca (egg case or 'purse')

These fascinating structures contain about 30-40 eggs each. The female cockroach carries her ootheca until the eggs hatch and the first instar nymphs emerge. For those of you who had never heard of this phenomenon before, you can read more HERE. 

In this case, we can see the emerging nymphs:

Laura noted that the ootheca was hard and solid when it first arrived in the lab so she added some saline and waited for 30 minutes. This is when the nymphs began to poke out and she was able to remove them for individual viewing. Thinking about a house infested with cockroaches and their ootheca makes me shudder!

Although cockroaches are not human ectoparasites, they have important medical and economic implications. Not only are they a source of anxiety for home owners, but they also contaminate food products with their feces and secretions, cause allergic responses in susceptible individuals, and can serve as mechanical vectors and reservoirs of various pathogens such as Shigella dysenteriae, Salmonella typhimurium, poliovirus, and Entamoeba histolytica.

Thanks again to Dr. Mitchell, Laura, Gwen, and Brie for donating this great case!