Gongylonema pulchrum Infection in a Resident of Williamsburg, Virginia, Verified by Genetic Analysis

We describe the thirteenth reported case of human infection with Gongylonema spp. in the United States and the first to be confirmed as Gongylonema pulchrum. The parasite described was isolated from the oral cavity of a resident of Williamsburg, Virginia. The identity of the parasite was verified through morphological and genetic approaches, and provided the first genetic confirmation of a Gongylonema sp. in humans. Nematodes of the genus Gongylonema have a cosmopoli- tan distribution and are frequently encountered in domestic livestock 1 but are only rarely described in humans. 2 Despite the apparent rarity of Gongylonema spp. in humans, healthcare providers should be aware of the possibility of human infec- tion, even in the absence of any obvious risk factors for para- site acquisition. We report a case of human infection by the parasitic nematode Gongylonema pulchrum in one of the authors (JDA) that was genetically verified by polymerase chain reaction (PCR) analysis. In December 2012, an otherwise healthy, 36-year-old man removed an intact, living, parasitic nematode from the mucosa of his cheek. The removal and subsequent analysis of the nematode occurred after approximately three months of symp- toms. These symptoms involved the sensation of intermittent rough areas present in the gum mucosa, which could be felt by the tongue. These rough patches would appear and disappear on a daily basis, giving the patient the indirect sense that there was an organism moving within the oral cavity. Direct move- ment of the nematode could not be detected while feeling the rough patch with his tongue. There were no other symptoms reported during this period. One day before removal of the parasite, the patient was able to visualize the rough patch in the mucosa of his lower lip after migration of the worm towards the opening of the mouth (Figure 1A). The patient, coincidentally trained as an invertebrate biologist, suspected the presence of a parasitic worm and immediately contacted his general practitioner, who then referred him to an oral surgeon for a formal medical evaluation. Upon presenting the oral surgeon with photo- graphic evidence (Figure 1A and B) and a detailed description and preliminary diagnosis of gongylonemiasis, the surgeon disputed the patient's self-diagnosis, claiming this was simply normal discoloration of the affected area. However, at the time of the medical examination, the worm had moved toward the back of the oral cavity and was not in a position for easy removal or visual inspection. The next morning, the patient awoke with the sensation that the worm was once again in the cheek mucosa near the front of the oral cavity. The patient used a pair of fine forceps (#5 super fine tip) to carefully remove the intact worm from the mucosa. The living and highly active parasite was trans- ported to the patient's research laboratory at the College of William and Mary for identification, photomicrography, and subsequent analysis. The patient showed no additional symp- toms after removal of this parasite and he was not adminis- tered treatment for nematode infection. The mucosa where the worm was removed recovered to its normal, healthy state within two days. The parasite, upon collection, was analyzed and photo- graphed while still alive by using a dissecting microscope. The long, transparent worm was readily identified as a nema- tode belonging to the genus Gongylonema through the pres-