Page 324 - parasitology for medical and clinical laboratoryprofessionals

304 GLOSSARY

organization whose stated aims are facilitating cooperation in Wet mount In order to allow light to pass through a micro-
international law. scopic preparation more effectively, a wet mount of water or
Urethral occlusion Characterized by the failure to pass normal physiological saline may be used for microscopic ex-
urine, the urethra may be blocked by edema, renal stones, or amination under a high-power objective.
parasite eggs such as in schistosomiasis. Wheatley modification Wheatley’s modification of
Urethritis Urethritis refers to inflammation of the urethra, Gomori’s trichrome technique is useful in examining stained
usually as a result of infection. fecal film for the presence of parasites.
Uterine pore Small opening through which eggs of certain Whipworms A slender, whip-shaped, parasitic nematode
tapeworms are discharged. worm (Trichuris trichiura) that often infects the intestine of
humans.
V WHO World Health Organization.
Wolbachia The term refers to a genus of bacteria that infect
Vacuolar Structure or organism with small cavities called vac- a wide variety of invertebrates that includes insects, spiders,
uoles spread through the cytoplasm of cells. crustaceans, and nematodes.
Vacuole Small cavity in the cytoplasm of a cell, bound by a Worms Used as a general description of a variety of parasites
single membrane and containing water, food, or metabolic other than protozoa.
waste. Wright stain Hematology stain for staining blood cells for
Vascular system Veins, arteries, and heart of an organism differentiation, morphology.
such as a mammal. Wright’s-Giemsa Combination hematological stain useful
Vector Organism that carries and perhaps transports para- for identifying intracellular parasites.
sites from one host to another; snails, other mollusks, and in- Wyle’s disease Caused by spirochetes that are also respon-
sects often serve as vectors for parasites as well as viruses and sible for relapsing fever, infectious jaundice, Lyme disease,
bacteria. sores, ulcers, and Vincent angina.
Vincent’s angina An acute communicable infection of the
respiratory tract and mouth marked by ulceration of the mu-
cous membrane. Y
Visceral larva migrans Caused by parasitic worms that in-
fect the intestines of dogs and cats. The dog parasite is called Yellow dog tick The American dog tick is from a genus of
Toxocara canis and the cat parasite is called Toxocara cati. The hard-bodied ticks of which most species are important vectors
disease is contracted where eggs in the feces of infected ani- of disease. It has a decorative white or yellow outer dorsal cov-
mals enter soil and allow the infection to spread to humans. ering called the scutum.
Vitamin B Used to treat pernicious anemia. Yellow fever This disease is an acute viral hemorrhagic dis-
12 ease resulting in jaundice due to the destruction of RBCs.
Volutin Granular, phosphoric substance that stains with basic
dyes and is found in the cytoplasm of some bacterial and fun- Aedes aegypti mosquitoes primarily but along with some other
gal cells. species are capable of transmitting the virus which is prevalent
in tropical and subtropical areas in South America and Africa.
W
Z
West Nile virus Mosquito-borne virus that can cause en-
cephalitis or meningitis (inflammation of the membranes sur- Zinc sulfate The specific gravity of zinc sulfate is adjusted
rounding the brain). to a particular level and is used as a fecal flotation medium for
Western blacklegged tick This tick is a three-host tick that finding the ova and some cysts of parasites.
primarily feeds on lizards or small rodents before adulthood and Zoonosis Diseases of animals, such as rabies, that can be
on large mammals, commonly deer, canids, and dusky-footed transmitted to humans.
woodrats. This organism is the principal vector for Lyme dis- Zygote This term is used for the union of two gametes resulting
ease in the western United States, as it readily bites humans. in a complete cell that may develop into a mature organism.