Page 316 - parasitology for medical and clinical laboratoryprofessionals

296 GLOSSARY

Lyme disease Caused by the spirochete bacterium Borrelia Malaria A hemolytic disease characterized by periods of fever
burgdorferi. A certain tick (of the genus Ixodes in the major- based on species of malaria infecting the victim; four species
ity of cases in the United States) carry these organisms. The of the genus Plasmodium infect humans, with differing geo-
disease was originally identified in Old Lyme, CT, but is now graphic locations, incubation times, fever cycles, symptoms,
found in most parts of the United States. There are three stages and manner of treatment.
of Lyme disease, that of primary, secondary, and tertiary. Malarial stippling This is a useful method for a rapid
Lymph nodes Small kidney-shaped enlargements of lym- and presumptive identification of the species of malarial
phoid tissue that lie along the lymphatic vessels; lymph nodes parasites.
are linked by lymphatic vessels and are found throughout the Malignant disorders Conditions are capable of invading
body. They function as filters for foreign materials such as or- into adjacent tissues, and are frequently capable of spreading
ganisms and contain WBC’s that use oxygen to destroy inva- to widespread tissues.
sive organisms Malnutrition General term for a medical condition re-
Lymphadenopathy Activation of lymphocytes and other sulting from insufficient diet but is caused by a number of
phagocytic white blood cells may cause an engorgement of malfunctions of the body as well as low intake of nutrients.
the lymph system, resulting in lymph nodes that are notice- Causes other than insufficient consumption relate to poor
ably larger and perhaps harder. Many infectious diseases cause absorption or excessive loss of nutrients, which often occurs
lymphadenopathy, but in addition rheumatoid arthritis, sar- in parasitosis.
coidosis, and a number of less common diseases may result in Maltese cross forms When a stained blood film shows a
lymphadenopathy. Maltese cross form for an organism, this may be presumptively
Lymphatic filariasis Refers to infections by worms of diagnostic of babesiosis and will differentiate between babesio-
Wuchereria bancrofti, Brugia malayi, and Brugia timori. sis and malaria.
These worms invade the lymphatic system, including the Mammillated Refers to a structure, organism, or cell that
lymph nodes and sometimes result in a disease called elephan- has relatively small protrusions from the exterior that occur
tiasis, due to the grotesquely large limbs of its victims. primarily on the surface.
Lymphatic varices Dilated submucosal veins that occur in Mandibles Lower jaw of a vertebrate animal is the most com-
various parts of the body such as the stomach and the exopha- mon use, but biting insect mandibles are a pair of appendages
gus, as well as in diseases of veins, lymphatic vessels and lymph near the insect’s mouth.
nodes. Mange Term for a persistent and contagious skin disease
Lymphocytes White blood cell that is responsible for much caused chiefly by sarcoptic mites for some types of the disease.
of the immune response. Lymphocytes are found primarily in They generally infect domestic animals including dogs but are
the lymph system, with a small percentage found in the circu- capable of affecting humans.
lating blood. Lymphocytes are divided into T-cells, B-cells, Maturation Process of reaching full development and size as
and natural killer (NK) cells. a growth process.
Mature proglottids Segments of the tapeworm, those clos-
M est to the scolex, that have matured to the point that they are
capable of producing eggs.
Macrogametes In heterogamous reproduction, where both Meningitis Inflammation of the membranes (arachnoid, pia,
male and female gametes exist, the larger and usually female of and dura mater) of the central nervous system; may be as result
a pair of conjugating gametes is called the macrogamete. of bacterial, viral, amoebal, mycobacterial (TB or associated
Macronucleus Found in eukaryocytes where the nucleus is organisms), or fungal infection, and in some cases from chemi-
organized into one large structure and is surrounded by a nu- cal irritation and from toxins.
clear membrane (prokaryocytes, as are most bacteria, lack the Measles Infection of the respiratory system by a virus seldom
organized nucleus surrounded by a nucleus). seen due to childhood immunizations. It is caused by a virus of
Macrophages Refers to a white cell called a monocyte that the genus Morbillivirus.
has left the vascular system and has matured (becomes much Meningoencephalitis Medical condition that concurrently
larger) in tissues of the body such as the spleen, tonsils, alveoli resembles meningitis, an infection or inflammation of the me-
of the lungs, lymph nodes, and the liver (Kuppfer cells) as well ninges surrounding the brain, and encephalitis which is an ac-
as many other tissue types, including that of the central ner- tual infection or inflammation of the brain.
vous system (microglia). Mecuric chloride Chemical used as a fixative when the pre-
Mad cow disease Disease caused by a subviral particle (i.e., servatives that include polyvinyl alcohol (PVA) are used.
prion), and is known variously as mad cow disease (bovine Merozoites In infections by Plasmodium spp., chiefly,
spongiform encephalopathy or BSE), scrapie, or Creutzfeldt- a breaking up of schizonts in the asexual reproductive
Jakob disease. process, merozoites are freed and invade other red blood
Malaise A nonspecific and generalized feeling of discomfort, cells, where they again undergo schizogony or develop
illness, or lack of well-being. The symptom can occur with into gametocytes (for sexual reproduction by union of two
almost any major disease condition. gametocytes).