Search results
Results From The WOW.Com Content Network
Histomonas meleagridis reproduces by binary fission.The free trophozoites are very delicate and can survive only for a few hours in the external environment. However, when they are transmitted between flocks in the eggs of Heterakis gallinarum, a cecal nematode, which in turn can be transmitted by earthworms that ingested the nematode eggs, they gain entry into the nematode eggs.
The eggs measure 50 to 60 μm by 20 to 30 μm, and have a thick shell flattened on one side. [18] The small size and colourlessness of the eggs make them invisible to the naked eye, except in barely visible clumps of thousands of eggs. Eggs may contain a developing embryo or a fully developed pinworm larva. [18] The larvae grow to 140–150 μm ...
Root-knot nematode females lay eggs into a gelatinous matrix produced by six rectal glands and secreted before and during egg laying. [19] The matrix initially forms a canal through the outer layers of root tissue and later surrounds the eggs, providing a barrier to water loss by maintaining a high moisture level around the eggs. [ 20 ]
Nematode sperm is thought to be the only eukaryotic cell without the globular protein G-actin. [49] Eggs may be embryonated or unembryonated when passed by the female, meaning their fertilized eggs may not yet be developed. A few species are known to be ovoviviparous. The eggs are protected by an outer shell, secreted by the uterus.
The direct counting of nematode eggs in feces is the method of choice for yearling animals, whereas in adult animals it may yield high variability due to a cow's immunity and low egg output. [41] Other biochemical methods have been developed to help more accurately diagnose O. ostertagi parasitism. These include the determination of specific ...
The egg is about 70–85 μm long by 44 μm wide, and the early stages of cleavage contain between 16 and 32 cells. The adult female is 18–30 millimetres ( 3 ⁄ 4 – 1 + 1 ⁄ 8 in) long and is easily recognized by its trademark "barber pole" coloration.
In egg-laying hens, heavy infection significantly reduces egg production. Diagnosis commonly is through the presence of eggs in host feces. Effective treatment is by using mebendazole, which is normally distributed to a flock of birds in their food and water. In addition, rearing the birds on hardware cloth assists in the elimination this parasite.
The release of oocytes (eggs) in female worms does not depend upon the presence of a male worm, although they may attract male worms using unidentified pheromones. [8] The first larval stage, microfilariae , are 300 μm in length and unsheathed, meaning that when they mature into microfilariae, they exit from the envelope of the egg.