9隻の虫体を片眼に認めた東洋眼虫症の1例

A case of infestation of Thelazia callipaeda in the conjunctival sac with nine worms in one eye

要約　目的：東洋眼虫（Thelazia callipaeda）が結膜囊に寄生した症例の報告。症例：89歳男性が数週前からの右眼異物感で受診した。イヌの飼育歴はないが，多数の野良猫が近所に住んでいる。所見：右眼瞼を翻転すると活発に蠕動する白色線条の虫体が下結膜囊内に4隻，上結膜囊内に2隻いた。これらすべてを摘出した。4週間後の再診時にさらに3隻の虫体を発見して摘出し，以後は再発はない。虫体は雄1隻，雌8隻で，平均体長は雄7.5mm，雌11.6mmであった。光学顕微鏡で東洋眼虫と同定した。mtDNAのCox 1遺伝子塩基配列の解析では従来の2報告と部分的に一致した。結論：結膜囊の東洋眼虫症では複数の虫体が寄生していることがあり，経過観察で注意が必要である。

Abstract.　Purpose：To report a case of infestation by Thelazia callipaeda in the conjunctival sac. Case：A 89-year-old male presented with foreign body sensation in the right eye. There were reportedly numerous free-living cats in the neighborhood. Findings：Four motile white worms were present in the lower and two in the upper conjunctival sac of the right eye. They were all manually removed. Three more worms were found and removed 4 weeks later. There has been no recurrence thereafter. Out of 9 worms,one was male and 8 were females. Their length averaged 7.5 mm for the male and 11.6mm for the females. They were identified as Thelazia callipaeda under light microscopy. Sequence of Cox 1 gene in mtDNA partially agreed with two previous reports from Italy and China. Conclusion：This case illustrates that careful follow-up is needed as numerous worms may be present when the conjunctival sac is infested by Thelazia callipaeda.