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Thelazia Californiensis
''Thelazia californiensis'' is a nematode that originates in the genus ''Thelazia'', which comes from phylum Nematoda. This worm has been known to cause Thelaziasis in hosts. Morphology As with most ''Thelazia'' worms, they are small parasites that average about 12-13 mm long. To differentiate between other members of this genus, ''T. californiensis'' has a vulva that opens mid-ventrally, while ''T. callipaeda'' has an anterior vulva. Hosts Similar to Thelazia callipaeda, the worm has definitive hosts in dogs, cats, sheep, and occasionally humans. They also use intermediate hosts to move around, specifically using the lesser house fly (''Fannia canicularis''). Life cycle The worm starts its life cycle by laying eggs in the tears and tear ducts of the host and the eggs are picked up by the flies. Because the eggs develop into larvae inside the fly, it is a parenthetic host. After developing in the fly, the larvae move so they can easily escape the fly's mouth when it feeds again ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nematode
The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-Parasitism, parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a broad range of environments. Less formally, they are categorized as Helminths, but are taxonomically classified along with Arthropod, arthropods, Tardigrade, tardigrades and other moulting animalia, animals in the clade Ecdysozoa, and unlike platyhelminthe, flatworms, have tubular digestion, digestive systems with openings at both ends. Like tardigrades, they have a reduced number of Hox genes, but their sister phylum Nematomorpha has kept the ancestral protostome Hox genotype, which shows that the reduction has occurred within the nematode phylum. Nematode species can be difficult to distinguish from one another. Consequently, estimates of the number of nematode species described to date vary by author and may change rapidly over ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thelaziasis
Thelaziasis is the term for infestation with parasitic nematodes of the genus ''Thelazia''. The adults of all ''Thelazia'' species discovered so far inhabit the eyes and associated tissues (such as eyelids, tear ducts, etc.) of various mammal and bird hosts, including humans. ''Thelazia'' nematodes are often referred to as "eyeworms". Signs and symptoms In animal and human hosts, infestation by ''Thelazia'' may be asymptomatic, though it frequently causes watery eyes ( epiphora), conjunctivitis, corneal opacity, or corneal ulcers (ulcerative keratitis). Infested humans have also reported "foreign body sensation"the feeling that something is in the eye. Cause Life cycle In the uterus of the adult female, the embryos develop into first-stage larvae (L1), which remain in the eggshell (sheath). The female deposits these sheathed larvae in the tears of the mammal or bird definitive host, and the larvae are ingested by tear-feeding flies. In the fly, the larvae "hatch" (exsheath), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thelazia Callipaeda
''Thelazia callipaeda'' is a parasitic nematode, and the most common cause of thelaziasis (or eyeworm infestation) in humans, dogs and cats. It was first discovered in the eyes of a dog in China in 1910. By 2000, over 250 human cases had been reported in the medical literature. Morphology The adult ''Thelazia callipaeda'' worm typically measures 5 to 20 mm in length and 250 to 800 µm in diameter. The males tend to be smaller than the females in size. In distinguishing this species from other worms, they have a distinct buccal capsule and a cuticle with spaced transverse striations giving it a ridged appearance. Adult females could also be identified by the position of their vulva which is anterior to the oesophagus-intestinal junction. The males can be distinguished by their possession of five pairs of postcloacal papillae. Hosts In addition to humans, cats and dogs, definitive hosts of ''T. callipaeda'' include the wolf (''Canis lupus''), raccoon dog (''Nyctereutes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lesser House Fly
The lesser house fly or little house fly, ''Fannia canicularis'', is somewhat smaller () than the common housefly. It is best known for its habit of entering buildings and flying in jagged patterns in the middle of a room. It is slender, and the median vein in the wing is straight. Larvae feed on all manner of decaying organic matter, including carrion. Morphology ''Fannia canicularis'' is a slim fly reaching a length of from 4 to 6 mm. The white-bordered eyes meet above in the male, a condition described as holoptic. In females, the eyes do not meet. The brown-grey thorax has three black, longitudinal stripes in the males. These are much less distinct in the female. The first two segments of the abdomen are translucently yellow with a dark-brown basal colour. The dark trapezoid marks of the males are hardly recognizable in the females. The halteres are yellowish. Development The females lay their eggs in batches of up to 50 and may lay up to 2,000 eggs altogether. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tear Duct
The nasolacrimal duct (also called the tear duct) carries tears from the lacrimal sac of the eye into the nasal cavity. The duct begins in the eye socket between the maxillary and lacrimal bones, from where it passes downwards and backwards. The opening of the nasolacrimal duct into the inferior nasal meatus of the nasal cavity is partially covered by a mucosal fold ( valve of Hasner or ''plica lacrimalis''). Excess tears flow through the nasolacrimal duct which drains into the inferior nasal meatus. This is the reason the nose starts to run when a person is crying or has watery eyes from an allergy, and why one can sometimes taste eye drops. This is for the same reason when applying some eye drops it is often advised to close the nasolacrimal duct by pressing it with a finger to prevent the medicine from escaping the eye and having unwanted side effects elsewhere in the body as it will proceed through the canal to the Nasal Cavity. Like the lacrimal sac, the duct is lined by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Larvae
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The larva's appearance is generally very different from the adult form (''e.g.'' caterpillars and butterflies) including different unique structures and organs that do not occur in the adult form. Their diet may also be considerably different. Larvae are frequently adapted to different environments than adults. For example, some larvae such as tadpoles live almost exclusively in aquatic environments, but can live outside water as adult frogs. By living in a distinct environment, larvae may be given shelter from predators and reduce competition for resources with the adult population. Animals in the larval stage will consume food to fuel their transition into the adult form. In some organisms like polychaetes and barnacles, adults are immobil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keratitis
Keratitis is a condition in which the eye's cornea, the clear dome on the front surface of the eye, becomes inflamed. The condition is often marked by moderate to intense pain and usually involves any of the following symptoms: pain, impaired eyesight, photophobia (light sensitivity), red eye and a 'gritty' sensation. Classification (by chronicity) Acute * Acute epithelial keratitis * Nummular keratitis * Interstitial keratitis * Disciform keratitis Chronic * Neurotrophic keratitis * Mucous plaque keratitis Classification (infective) Viral * Herpes simplex keratitis (dendritic keratitis). Viral infection of the cornea is often caused by the herpes simplex virus (HSV) which frequently leaves what is called a 'dendritic ulcer'. * Herpes zoster keratitis, associated with herpes zoster ophthalmicus, which is a form of shingles. Bacterial * Bacterial keratitis. Bacterial infection of the cornea can follow from an injury or from wearing contact lenses. The bacteria involved ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conjunctivitis
Conjunctivitis, also known as pink eye, is inflammation of the conjunctiva, outermost layer of the white part of the eye and the inner surface of the eyelid. It makes the eye appear pink or reddish. Pain, burning, scratchiness, or itchiness may occur. The affected eye may have increased tears or be "stuck shut" in the morning. Swelling of the sclera, white part of the eye may also occur. Itching is more common in cases due to allergies. Conjunctivitis can affect one or both eyes. The most common infectious causes are viral infection, viral followed by bacterial infection, bacterial. The viral infection may occur along with other symptoms of a common cold. Both viral and bacterial cases are easily spread between people. Allergies to pollen or animal hair are also a common cause. Diagnosis is often based on signs and symptoms. Occasionally, a sample of the discharge is sent for microbial culture, culture. Prevention is partly by handwashing. Treatment depends on the underlying c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nematodes
The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a broad range of environments. Less formally, they are categorized as Helminths, but are taxonomically classified along with arthropods, tardigrades and other moulting animals in the clade Ecdysozoa, and unlike flatworms, have tubular digestive systems with openings at both ends. Like tardigrades, they have a reduced number of Hox genes, but their sister phylum Nematomorpha has kept the ancestral protostome Hox genotype, which shows that the reduction has occurred within the nematode phylum. Nematode species can be difficult to distinguish from one another. Consequently, estimates of the number of nematode species described to date vary by author and may change rapidly over time. A 2013 survey of animal biodiversity published in the mega jo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
