A brief report on Gnathostoma spinigerum specimens obtained from human cases.

A total of 23 gnathostome specimens different stages from the Hospital for Tropical Diseases, other general hospitals and medical clinics in Bangkok metropolitan area and central Thailand were identified as G. spinigerum. The various stages were as follows: Five advanced third-stage larvae (22.0%) of various sizes; 2.20-3.50 mm X 0.40-0.63 mm were removed from the skin, mucous membrane and the eyeball, of which the smallest measured 2.20 X 0.40 mm. Fourteen immature worms of both sexes were from the skin and mucous membrane, one spontaneously voided in the urine. The sizes varied from 4.63-9.35 mm X 0.60- 1.05 mm (8 male worms), and 3.83-16.25 mm. X 0.83-1.0 mm (6 female worms). All these immature worms had 8 rows of complete cephalic-hooklets with the exception of two with 6 and 7 rows of complete cephalic-hooklets. Four mature males size ranged from 9.9-12.5 mm X 1.0-1.25 mm. The smallest was removed from the abdominal skin of a newly born 7-day old baby evidently the case was prenatally transmitted.

Electron microscopy of the advanced third-stage larvae of Gnathostoma spinigerum.

The morphological structures of the advanced third-stage larvae of Gnathostoma spinigerum are reported by using the scanning electron microscope. On the head-bulb, the larva bears two lateral lips, two labial papillae on each lip with an amphid between them. The head-bulb bears four transverse row of well-developed single-pointed hooklets. The number of the hooklets in each row increases posteriorly. The appearance of the hooklets by dorsal view and lateral view is also described. The whole body cuticle is transversely striated and covered with transverse rows of single-pointed spines which are dense on the anterior third of the body and became gradually less both in number and size towards the posterior extremity. The average number of transverse rows of these cuticular striations is 234. A pair of cervical papillae and an excretory pore are located on the anterior third of the body. A pair of body papillae is seen on the posterior half of the body. The subterminal anus is seen in the posterior extremity.

Gnathostomiasis in Southeast Asia.

Five species of Gnathostoma are at present reported from Southeast Asia with specific diagnostic characteristic of each. Also important references relating to the specific characters of the species concerned were mentioned, and the known experimental life cycles of three species namely G. spinigerum, G. hispidum, and G. doloresi found in the region were compared. The incomplete experimental study on the life cycle of G. vietnamicum is presented but the investigation on the life cycle of G. malaysiae is not yet initiated. Methods of transmission, symptoms and signs, the diagnosis and treatment of animal and human gnathostomiasis were also summarized. Effective therapeutic value of many anthelmintic drugs has not been satisfactory, by screening test on white mice previously infected in the tissue with G. spinigerum larvae. However, successful result of treatment was reported on one Japanese gnathostomiasis patient with thiabendazole. In the treatment of animal gnathostomiasis, Ancylol disophenol seems to be he effective drug for eliminating adult and migrating stage in the experimentally infected cats. Brief preventive measures against human gnathostomiasis was mentioned.

Chemotherapy of feline Gnathostoma spinigerum migrating stage with multiple subcutaneous doses of ancylol.

Twelve doses of Ancylol Disophenol at 0.05 ml per pound body weight administered subcutaneously was shown to be an effective chemotherapeutic agent against migrating stage of G. spinigerum in cats. A further investigation is required to determine whether this regimen is the minimum effective therapeutic dosage. None of eight cats treated with 12 doses of 0.02 to 0.05 ml per pound body weight showed signs or symptoms of toxicity due to the treatment and there were not gross pathological changes of the organs observed on necropsy of the animals.