Table 1.
Differentiating morphological features, geographic distribution, and known hosts of female Thelazia spp.3,6–8,14
| Differentiating morphological features of adult female Thelazia spp. nematodes | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Thelazia species | Length of adult female (mm) | Diameter at widest point (μm) | Distance of vulval opening from anterior cephalic region (μm) | Position of vulval opening relative to esophago-intestinal junction | Morphological features of vulval opening | Morphological features of buccal cavity | Morphology of cuticular ridges in midsection | Morphological features of female posterior | Reported geographic range | Reported hosts |
| Thelazia bubalis | 6.5–7.8 | 250 | 900 | ND | ND | ND | ND | – | India | Water buffalo |
| Thelazia californiensis | 12–18.8 | 330–420 | 700–1,000 | Posterior | No distinctive features | Deep and cup like | Rounded, moderately prominent, and widely spaced | Anus protrudes, two phasmids protrude from tip of tail, and no unilateral tapering | USA and Brazil | Humans, canines, felines, bears, deer, and sheep |
| Thelazia callipaeda | 10.7–18.5 | 290–510 | 520–710 | Anterior | Short flap at opening | Wide and cup like | Serrated, very prominent, and tightly spaced | Anus protrudes, two phasmids protrude from tip of tail, and no unilateral tapering | Europe, Asia, and India | Humans, monkeys, canines, felines, and rabbits |
| Thelazia ershowi | 5.0–8.7 | 188–207 | 395–489 | ND | ND | ND | ND | ND | Former Union of Soviet Socialist Republics | Pig |
| Thelazia gulosa | 8.0–11.5 | 350–460 | 460–610 | Same level | No distinctive features | Deep and cup like | Rounded, very prominent, and widely spaced | Anus does not protrude, two postanal phasmids, and unilateral tapering postanally | North America, Europe, former USSR, and Australia | Human, Cattle |
| Thelazia lacrymalis | 10.5–12.5 | 279–289 | 493–593 | Posterior | No distinctive features | Deep and cup like | Rounded, not prominent, and tightly spaced | Anus does not protrude, two postanal phasmids, and unilateral tapering postanally | North America, South America, Europe, Asia, and North Africa | Buffalo, camel, dog, and equine species |
| Thelazia leesei | 14–21 | 400 | 425–440 | Same level | ND | ND | ND | ND | Europe, India, Central Asia, and Africa | Camels |
| Thelazia rhodesi | 12.5–20.5 | 300–500 | 505–536 | Posterior | Cuticular pattern differs, vulva protrudes | Deep and cup like | Serrated, very prominent, and widely spaced | Anus protrudes, one phasmids protrudes from tip of tail, and unilateral tapering postanally | North America, Europe, United Kingdom, Asia, Ghana, Zambia, Afghanistan, and Japan | Cattle, buffalo, zebu, bison horses, sheep, and goats |
| Thelazia skrjabini | 11–19 | 178–378 | 410–710 | Posterior | Protrudes | Short and indistinct | Rounded, scarcely visible, and widely spaced | Anus protrudes, two postanal phasmids and rounded with no unilateral tapering | North America, Europe, former USSR, India, and Australia | Cattle, buffalo, and horses |
ND = no data.