For instance, Wyeomyia larvae typically get frozen into solid lumps of ice during winter and only complete their development in spring. The eggs of some species of Aedes remain unharmed in diapause if they dry out, and hatch later when they are covered by water. Eggs hatch to become larvae, which grow until they are able to change into pupae. The adult mosquito emerges from the mature pupa as it floats at the water surface. Bloodsucking mosquitoes, depending on species, sex, and weather conditions, have potential adult lifespans ranging from as short as a week to as long as several months. Some species can overwinter as adults in diapause. Breeding
In most species, adult females lay their eggs in stagnant water: some lay near the waters edge while others attach their eggs to aquatic plants. Each species selects the situation of the water into which it lays its eggs and does so according to its own ecological adaptations. Some breed in lakes, some in temporary puddles. Some breed in marshes, some in salt-marshes. Among those that breed in salt water (such as Opifex fuscus), some are equally at home in fresh and salt water up to about one-third the concentration of seawater, whereas others must acclimatize themselves to the salinity. Such differences are important because certain ecological preferences keep mosquitoes away from most humans, whereas other preferences bring them right into houses at night.
Diffuse unilateral subacute neuroretinitis (DUSN) is a rare condition that occurs in otherwise healthy, often young patients and is due to the presence of a subretinal nematode. Signs and symptoms
The clinical findings in this disease can be divided into acute and end-stage manifestations:
In the acute phase, patients often present with decreased visual acuity, vitritis, papillitis, and crops of gray-white or yellow-white outer retinal lesions. The clustering of the retinal lesions is important because this often helps to localize the causative nematode. If left untreated, patients ultimately develop late sequel, which may include optic atrophy, retinal arterial narrowing, diffuse retinal pigment epithelial changes, and an abnormal electroretinogram. The late findings of this condition are often misinterpreted as unilateral retinitis pigmentosa. Cause
DUSN may be caused by a helminthic infection with Toxocara canis, Baylisascaris procyonis, or Ancylostoma caninum. The characteristic lesions are believed to result from a single nematode migrating within the subretinal space. Although previously thought to be endemic in some areas, that belief was likely due to under awareness. DUSN has been diagnosed in patients in many countries and climates including America, Brazil, China and India. Diagnosis
Treatment
If the nematode can be seen by an ophthalmologist, which occurs in less than half of cases, it should be treated with photocoagulation for extramacular location and surgical removal in case the larva is lying in the macula. After the worm is killed, visual acuity loss usually does not progress. Alternatively, Antihelminthic treatment such as high dose oral Albendazole and prednisolone may be used. References


== External links ==