A 35-year-old young man complained of his left eye painful and vision loss for 1 week. The patient went to our hospital and slit-lamp examination found a curly slender worm body on the surface of the iris, which was wrapped by the surrounding organizing membrane (Figure 1), with the appearance of uveitis like several mutton fat keratic precipitates and ++ flare and cells in both anterior chamber and vitreous cavity. No parasites were found in the fundus and vitreous cavity. The best corrected visual acuity of both eyes was 20/20, and the intraocular pressure was 20 mmHg (the range of normal intraocular pressure is 10–21 mmHg). At the same time, computed tomography scans of the head and chest and colour Doppler ultrasound of the abdomen were performed on the patient, and no positive findings were found. At the same time, we also checked the patient’s faeces, and no worm bodies and eggs were found. The patient’s blood was checked, and it was found that monocytes (0.76 × 109/l) and eosinophils (0.56 × 109/l) were elevated, and both erythrocyte sedimentation rate and C reactive protein were negative.
The patient’s left anterior segment photo showing that the parasite located on the surface of the subtemporal iris, wrapped by organizing membrane.
The parasite was 4 mm long and 0.25 mm wide. It could be seen under an optical microscope that there were four small hooks on the head, and the number of small hooks in each circle gradually increased from front to back. From the back view of the header, it could be seen that the first row of small hooks was smaller, and the other three rows were almost the same size. There were horizontal stripes on the surface of the worm body after the head hook, and a ring of small spines was arranged along with the horizontal stripes. The small spines were arranged densely and largely in the front part of the body, and gradually became smaller and thinner from the back to the back part. In the internal structure of the worm, a rod-shaped oesophagus could be seen, which was connected to the thick intestine. The intestinal epithelial cells were cylindrical with multiple nuclei. There were four obvious tubular neck capsules in the front 1/4 of the body, which opened on the head ball. The tail end was conical. The morphological characteristics of the worms accorded with the characteristics of the third-stage larvae of G. spinigerum.
The patient is a native of Xinjin County, Chengdu City, Sichuan Province, and has no history of foreign travel except Phuket, Thailand (7 years ago). In China, he has never been to border areas such as Yunnan and Guangxi. The patient has a history of eating raw food: he had eaten raw beef dozens of times and salmon sashimi several times in the past. One week before the onset of illness, the patient also ate raw beef locally (Xinjin County, Chengdu City, Sichuan Province). The patient had eaten cooked loach and Monopterus albus, but had no life history such as keeping pets.
We performed surgery to remove the parasite from the patient, made a transparent limbal incision during the operation, separated the larva with an iris restorer, clamped out it with tweezers and closed the incision. The extracted larva body is shown in Figure 2. It was identified as Gnathostoma, and the morphological characteristics of the worm accorded with the characteristics of the third-stage larva of Gnasthosoma spinigerum by Shandong Institute of Parasitic Diseases (Figure 2). We did not find other larvae after the operation. We also checked the contralateral eye and found no positive findings.
Among the cases reported in China, the most common is the case under the skin, followed by the gastrointestinal tract, but there is no case report in the eye, and the larvae of the most cases in China is G. spinigerum.1–3 So our case is the first case reported in the eye in China. The reports of cases in China are mainly concentrated in Guangdong, Guangxi, Fujian, Shanghai and other places. This is also the first report in inland areas, especially in western regions such as Sichuan. Guangdong, Guangxi, Fujian and Shanghai are all coastal areas with rich aquatic products. The locals have a long tradition of eating raw food. In the western region, this tradition is rare. This should be the reason for the large number of cases in coastal areas.
Authors’ contributions
Shuang Wang and Juan Guo did the surgery and participated in preparation of the manuscript. Jun Huang, Feng Miao and Ling Zhang helped identify the parasite. All authors read and approved the final manuscript.
Funding
Not applicable.
Conflict of interest
None declared.
