Volume 11, Number 2 - December 1964
THE COVER PICTURE shows a tick. These arthropods spread Rocky Mountain spotted fever and may calise tick paralysis.
by Robert J. Boles
ABOUT THIS ISSUE
Published by The Kansas State Teachers College of Emporia
Prepared and Issued by The Department of Biology, with the cooperation of the Division of Education
Acting Editor: Carl W. Prophet, Department of Biology
Editorial Committee: Ina M. Borman, Robert F. Clarke, Helen M. Douglass, Gilbert A. Leisman, David F. Parmelee
Online format by: Terri Weast
The Kansas School Naturalist is sent upon request, free of charge, to Kansas teachers, school board members and administrators, librarians, conservationists, youth leaders, and other adults interested in nature education. Back numbers are sent tree as long as the supply lasts, except Vol. 5, No.3, Poisonous Snakes of Kansas. Copies of this issue may be obtained for 25 cents each postpaid. Send orders to The Kansas School Naturalist, Department of Biology, Kansas State Teachers College, Emporia, Kansas.
The Kansas School Naturalist is published in October, December, February, and April of each year by The Kansas State Teachers College, 1200 Commercial Street, Emporia, Kansas. Second-class postage paid at Emporia, Kansas.
ABOUT THE AUTHOR
The text and drawings of this issue of The Naturalist were prepared by Dr. Robert Boles, Assistant Professor of Biology at the Kansas State Teachers College. Many readers will recall th at the artistic ability of Dr. Boles has been employed OJ; numerous occasions in previous issues of The Naturalist.
by Robert J. Boles
Most of the 3,000,000,000 people in the world will sometime during their lives be unwilling hosts to one or more uninvited, unwanted, and often injurious "partners." These may be one-celled animals, round or flatworms, insects, mites, or ticks. Some cause serious diseases, while others serve to spread disease-producing organisms from host to host.
When one animal lives upon or within another animal, getting its living at the expense of that animal (the host), the condition is called parasitism. Several of the important parasites of humans and om domestic
animals, their life histories, symptoms, treatment, and control, will be discussed in this issue of
One of the great benefits of living in these United States is relative freedom from the most injurious human parasites. Our high standard of living, not only from the standpoint of sanitary conditions, but also from an adequate diet, helps prevent the incidence of parasite infection, and also helps keep some very serious human diseases from becoming established in this country.
Parasites reach their greatest numbers and do their greatest damage in countries in which people are over-crowded and undernourished and use water supplies which are not given adequate treatment. Unfortunately, this includes some of the most populous portions of the earth, such as India and China.
During World War II great numbers of our soldiers, fighting in foreign countries, were the unwilling victims of parasite infections. Our experiences in this great conflict, along with an increasing realization that no disease is more than a few hours away by modern methods of transportation, make it essential that we know something of these parasites and the human suffering they may cause or carry.
Chandler and Read (1961) state:
In these days of international travel as common as interstate travel was a generation ago, many a home-town physician has to deal with patients suffering from diseases which previously had been only names to him. Also the opportunity for dissemination of parasites or vectors entering as stowaways
in airplanes, or on or in the bodies of passengers, is greater than ever before. Even when it took weeks
to months to go from continent to continent, dispersal of parasites was common. Traders brought filariasis from the South Seas to Egypt, slaves brought hookworms and schistosomes from Africa to America, and trading vessels carried yellow fever from the American tropics to New York and Philadelphia. What can be expected when we can have breakfast in Colombia and supper in Florida?
Up until the middle of the seventeenth century the knowledge of parasitology was limited to the recognition of such obvious external parasites as lice and fleas, and a few internal worms too large to be overlooked, such as pinworms and tapeworms. These parasites were thought to be natural body products, as are warts and boils. Many people believed such organisms were produced by "spontaneous generation," just as they
believed that old rags would turn to mice and mud into frogs.
Some of the important advances in the field of parasitology have been:
- The discovery of the microscope, which allowed a careful study of the minute and immature forms.
- The introduction of experimental methods, which allowed scientists to work out complicated life histories, and to identify the various stages and hosts involved.
- The discovery that insects (and their relatives, like mites and ticks) can serve as vectors - that is, can carry diseases from host to host.
- The discovery that special chemicals may be introduced into the body to 'help control, or even cure, various parasitic diseases.
- The discovery of immunity, which is the ability of the body to build up special defenses to help fight the invading organisms.
SOME DISEASES CAUSED BY ONE-CELLED ANIMALS
A tiny protozoan (Entmnoeba histolytica) which has become adapted to live in the human large intestine causes this disease.
Anyone traveling in foreign countries, or even in areas of the United States where water supplies and sanitary facilities are not carefully supervised, must be extremely cautious or they may contact amebic dysentery. Because this disease-producing organism is so widely spread over the world, and is so common in the human large intestine, it must be ranked as one of the most important human parasites. Some parasitologists working in Egyptian villages near Cairo found practicallv 100% of the people infected!
Sometimes defective plumbing may lead to serious outbreaks. Such an outbreak occurred in South Bend, Indiana, in 1953, resulting in over 750 cases and several deaths.
The parasites may sometimes leave the large intestine, where they are normally found, and invade the liver, lungs, and other organs, causing large amebic abscesses to develop.
Like many protozoan diseases, amebiasis, if left untreated, tends to become chronic and to persist indefinitely.
A diet high in proteins and vitamins helps to reduce the seriousness of the disease. Some people go into a sort of "partnership" with the organism, showing no ill effects as a result of their presence, but spreading the disease to those with whom they associate. Such persons are known as "carriers."
Prompt relief from acute dysentery may be brought about in many cases by the administration of certain antibiotics, such as Terramycin and Aureomycin. Control of chronic cases is more difficult.
Sanitation and protection of water and vegetables from pollution are essential for prevention.
Food handlers are probably one of the most important means of transportation of the organism in large cities. Anyone handling food items intended for public consumption should be required to pass a careful health examination at regular intervals.
Careful washing of the hands with soap and water before eating or handling food will go far toward helping to eliminate the danger of infection.
A serious human disease that claims a considerable number of human lives each year in South America is called Chagas' disease. It is caused by a little one-celled animal (Schizotrypanum cruzi), and spread by a large, bloodsucking bug (Panstrongylus megistus). The Saturday Evening Post of November 9, 1963, carried a pathetic story of a Brazilian town in which the people are literally waiting to die from the disease.
The parasite normally lives in armadillos, opossums, bats, raccoons, and rodents. It can also survive in many other mammals. This makes it difficult, if not impossible, to eliminate the parasite from an area. Human infection occurs all the way from Mexico to Northern Argentina. It is surprising that only one human infection has been reported in the United States, as many species of blood-sucking bugs (including many found in houses) in the Southwest have been found to be infected with the parasite.
The disease is especially common among infants and young children. Their eyelids swell, severe headaches
develop, and there is a more or less continuous fever. If the patient survives, the disease goes into a chronic stage that may last for life. Nearly all fatal cases are due to injury to the heart muscle.
There is no successful treatment known, although a few antibiotics will give temporary relief. For prevention,
the house should be sprayed or dusted with the powerful insecticides Lindane or Dieldrin. In areas of South America where better houses are being built there has been a decline in the number of infections.
This disabling and disfiguring disease is especially prevalent in tropical America, Africa, and the Far East. Caused by a tiny slender, coiled organism much like the one causing the dread veneral disease syphilis, it attacks dark-skinned races almost exclusively.
In many areas practically 100% of the children get the disease. Many adults suffer from later manifestations of the disease, such as ulcerated lesions and bone deformities.
Yaws is transmitted through breaks in the skin when flies, especially eye flies, become infected while feeding upon parasite-filled skin sores.
Fortunately, the disease responds readily to treatment with penicillin. Before the discovery of this antibiotic,
there were estimated to be a half million cases of yaws. Nation-wide campaigns, sponsored by the World Health Organization, have helped reduce the number of cases.
SOME DISEASES CAUSED BY PARASITIC WORMS
Chinese Liver Fluke Infection
This important human parasite is widely distributed in the Far East from Korea and Japan through China to Indo-China and India. Although the liver fluke is common in cats and dogs throughout this area, human infections are limited to localities where the people prefer to eat raw fish. There are estimated to be nearly 20,000,000 human cases of this disease.
This parasitic flatworm has a very complicated life cycle. The eggs hatch into tiny swimming larvae that are eaten by certain small snails. Inside the snails the larvae develop into bag-like structures, each of which produces a number of other sac-like bodies. This stage in turn produces large numbers of a tadpole-shaped stage that escape from the snail and enter a fresh-water fish, where they encyst in the flesh. When eaten along with raw fish each of these cysts develops into an adult fluke, which finds its way to the liver of its human host, where it dines upon the rich supply of blood and tissue around it. Eggs escape from the body with the feces, and the larvae are set free to start a new cycle when the raw human wastes are used to fertilize such irrigated crops as rice. A single egg may, by means of the multiplication that occurs in the snail, give rise to over 100,000 new individuals!
The parasites not only damage the liver tissue of the host, but they may even clog the bile ducts leading
to the small intestine. Light infections may show no symptoms at all; more severe infections are accompanied by diarrhea, often with blood, edema, enlarged liver, and abdominal discomfort.
The disease is difficult to treat, and complete cures are not usually obtained.
Schistosome - highly magnified
Prevention would be possible if "night soil," as the natives call the human wastes, were stored until the larvae died, or were treated with ammonium sulfate to kill the eggs before snails got to them. The best preventative method would be to prohibit the sale of raw fish and to educate the people to the dangers of eating fish which has not been cooked. Simple as this sounds, it is doubtful if these measures will be put into effect, as it is never easy to change a well-established taste, and the cost of fuel for cooking the fish would be a real economic factor in much of the infected area.
The Broad Tapeworm of Fish
The largest tapeworm found in man has been present in the people of Europe for many years. In Finland about one out of every five people have this worm, and in some local areas in the Baltics nearly 100% of the population are infected. The worm is not confined to Europe in its distribution, but occurs in many other parts of the world. In the United States it has been found in Michigan, Minnesota, Wyoming, Alaska, and Florida.
It is not known whether the tapeworm was brought to this country by Scandinavian lumbermen or whether wild carnivores carried the worm to North America across the Bering Straits. This tapeworm (Dibothriocephalus latus) is truly a "monster."
During its adult stage in the small intestine, it may grow to over 30 feet in length (one 60 foot individual was reported) and have over 4000 segments to its body. One Russian woman was reported to have had six worms that were over 290 feet long, and another had 143 worms!
Like many internal parasites, this worm has a very complicated life cycle. Eggs (one worm may lay over 35,000 a day) passing into the water with untreated human sewage hatch into little swimming larvae (coracidia), which must be eaten by tiny relatives of the crayfish, called copepods, that live in the open water of lakes. Inside the copepod the larvae form cysts (the procercoid stage).
When small fish eat the copepod, the procercoid is released from its cyst covering, and, entering the flesh of the fish, again encysts, this time to form the plerocercoid stage.
The plerocercoid stage is not the final stage, as still another intermediate host is involved. This host, a large carnivorous fish, gets the worm when it preys upon the smaller fish. In some of the small lakes in northern United States and Canada 50 to 75% of the pikes and walleyes are infected with the larval stage of this tapeworm.
Man gets the adult stage of the worm when he eats raw or improperly cooked fish whose flesh contains the plerocercoid larvae.
Though the ill effects produced by such tapeworms as those from beef and pork are usually highly exaggerated, the broad fish tapeworm does cause pathological symptoms. Common effects of infection are abdominal pain, loss of weight, and progressive weakness. However, probably the most severe effect is a very severe anemia of the pernicious type. Fortunately, most worms do not cause this severe anemia.
The control of infection must depend primarily upon more careful cooking of fish. Better sewage disposal would also help, as would stopping the feeding of raw fish to cats and dogs which may also harbor the adult worm.
A one-celled organism. Trypanosoma, causes African sleeping sickness (highly magnified).
Larvae of trichina worms encysted in muscle fibers of pork (much enlarged).
Tsetse Fly, the insect that spreads African sleeping sickness.
A fluke (much enlarged).
Practically every Caucasian family, no matter how fastidious it may be, will probably at some time play host to a small worm, commonly referred to as the pinworm or seatworm. The worms are found all over the world, though they are rare in the tropics. An estimated 30 to 60% of the white children in cities are infected with pinworms. Colored races are less susceptible.
The adult worms, which are a little less than a half inch long, live in the intestine, and may even enter the appendix. They may often be seen as a mass of tiny white worms wriggling in the feces after taking a laxative or an enema.
|Some Important Human Diseases||African Sleeping Sickness||Malaria|
|Causative Organism||A one-celled animal, Trypanosoma spp.||A one-celled animal, Plasmodium spp.|
|Way Disease is Spread or Contacted||Bite of a blood-sucking tsetse fly||Bite of Anopheles mosquito|
|Symptoms||A sore appears at site of bite of infected fly; fever, headache, weakness, enlarged glands; lowered resistance to other diseases; unconsciousness when parasite invades cerebra-spinal fluid of brain and spinal cord.||Recurring chills and fever; teeth chatter; sweating may be profuse; lowered vitality; anemia; spleen becomes
|Areas Where Disease Most Often Occurs||Occurs over a wide area in tropical Africa, especially along some of the large rivers, such as the Congo and the Niger.||West Africa, South America, Russia, Palestine, India, (eliminated from continental United States in 1951) .|
|Treatment||Two drugs (Bayer 205 and pentamidine) are now used to treat most cases. The antibiotic Puromycin has shown some promise as a treatment.||Use of new anti-malarial drugs (e.g., chloroquin and paludrine); daraprim has shown much promise.|
|Control or Prevention||Therapeutic and prophylactic treatment can reduce human infection to a low level; get rid of tsetse flies.||Good nutrition; spray with insecticides (e.g., DDT); dmint1se; use mosquito-eating fish, such as Gambusia and Tilapia.|
|Some Important Human Diseases||Schistosomiasis||Hookworms|
|Causative Organism||A small flat worm, or fluke, Schistosoma spp.||A small round worm, Necator americanus|
|Way Disease is Spread or Contacted||Immature (cercaria) stage of fluke enters the skin when the victim wades, swims in, or drinks contaminated water.||Larval worms bore through thin skin of toes or fingers.|
|Symptoms||Irritating cough; itching rash, local dermatitis; fever, aches, decrease in white blood corpuscles; diarrhea; enlargement of liver and spleen; bloated abdomen and emaciation.||"Ground itch" or "Dew sores" where parasites entered the skin; pneumonia-like symptoms as larvae bore through lungs;
nausea; intestinal discomfort;
anemia; stunting of children's
growth and intelligence.
|Areas Where Disease Most Often Occurs||Orient, especially Egypt, China (may he over 100,000,000 cases in the world).||May be found practically anywhere in the world where the winters are not too cold to kill the larval stages in the soil; more prevalent in southern areas.|
|Treatment||Use special drugs (e.g., Fuadin, Anthiomaline); surgical treatment may be necessary if spleen is too much enlarged.||Use of a new chemical, Hexylresorcinol, will get rid of most worms; iron, calcium , and proteins in diet essential.|
|Control or Prevention||Education and sanitation; treatment of infected host; elimination of snails.||Sanitary disposal of human wastes; wear shoes; a complete diet.|
|Some Important Human Diseases||Trichinosis or Trichiniasis||Filariasis|
|Causative Organism||A tiny round worm, Trinchinella spiralis||A small round worm, Wuchereria bancrofti|
|Way Disease is Spread or Contacted||Eating rare or uncooked pork||Bite of various species of mosquitoes.|
|Symptoms||Diarrhea, nausea, abdominal pains; flushing; often a fever; intense muscular pains; difficulty in chewing and breathing, face becomes puffy; pneumonia may develop.||Inflamed lymph glands; may be excessive swelling of arms and legs; skin becomes hard and dry; headache; backache; fatigue.|
|Areas Where Disease Most Often Occurs||Primarily a parasite of Europe, the United States and Arctic regions; some may occur in Mexico and Chili; almost none in tropical areas.||Very wide-spread and important
parasite in warm countries. Common in Africa, India, China, Japan , South Pacific Islands.
|Treatment||Nothing is known that will kill larvae after they become emhedded in muscle tissue; nothing has been found that is too effective for expelling adult worms from intestine; cortisone and ACTH may help cut down inflammatory response of patient.||Antimony compounds to kill larvae in blood; arsen ic drugs to kill adults; a new drug, Hetrazan, may prove effective.|
|Control or Prevention||Cook all pork thoroughly; quick cooling to -34 degrees renders trichinae larvae non-infective; do not feed raw garbage to hogs.||Largely a matter of mosquito control.|
|Some Important Human Diseases||Rocky Mountain Spotted Fever|
|Causative Organism||A very tiny virus-like organism, Dermacentroxenus rickettsii|
|Way Disease is Spread or Contacted||Bite of various species of ticks, especially Dermacentor
|Symptoms||Fever; rash or purplish spotting of skin; nervous and
gastrointestinal disturbances; a marked reduction of leucocytes.
|Areas Where Disease Most Often Occurs||Has now spread over most of the United States; more prevalent in areas where ticks are common (e.g., wooded and brushy terrain).|
|Treatment||Responds to treatment with certain antibiotics, particularly to Terramycin and Aureomycin|
|Control or Prevention||Destroy ticks around premises; check carefully for ticks on the body, especially following a camping: or outdoor trip in the summer.|
Contact with the air stimulates the female worm to deposit her very tiny eggs around the anal opening of the host, usually at night. Over 10,000 eggs may be laid at one time. Intense itching results from the movements of the females.
Eggs probably get into the body most often when they are breathed in with the air or are carried to the mouth by the hands. Scratching, due to the intense itching results in great numbers of the eggs becoming lodged under the fingernails. Children chewing their nails or licking or sucking their fingers are easily infected. Shaking contaminated clothing or bedding may fill the air with eggs which maybe inhaled or settle as dust to be inhaled into the lungs later.
Eggs may scatter everywhere in the home-clothing, bedding, towels and washcloths, soap, floor, furniture, rugs - often into every room of a house occupied by children. Washing machines in self-service laundries may serve to spread the eggs to new families if the water is not hot enough. Scratching, however, seems to be the most common cause of heavy infections.
Itching caused by the migration of the worms and the allergic condition some people develop may cause loss of sleep, restlessness, and nervousness. No doubt many a "wormy" child has been raked over the coals by an unknowing teacher for disturbing the class or for not doing better work.
Several drugs, such as Terramycin and hexylresorcinol, will remove many of the worms. However, complete cure and prevention of reinfection is difficult, requiring non-porous pajamas which will not let the eggs escape into the bedding, daily changing and sterilization of bedclothes, towels, and underwear, use of ointments, frequent washing of the hands, close clipping of the fingernails, a dustless house - and constant work and vigilance on the part of the parents. Chandler (1961) states that efforts to eliminate infection completely may actually lead to "pinworm neurosis" that is worse than a mild pinworm infection!
SOME DISEASES CAUSED OR CARRIED BY ARTHROPODS
The "Itch" or Scabies
Many parents can remember having had, or hearing their parents tell of, the so-called "seven-year itch." Sometimes people jokingly said that a good scratcher could scratch his out in a little less than three years. Many old-timers thought the disease to have been caused by "bad blood." Now we know that scabies, caused by a minute whitish mite barely visible to the naked eye, need not persist for seven years, but if untreated, may conceivably be with an individual for many more than seven years.
A female mite, full of eggs, digs little crooked tunnels in the epidermis, especially where the skin is thin and delicate. She lays two or three eggs a day as she bores along under the skin. After some 35 to 50 eggs have been laid, the female dies. Young mites, hatching in the burrow where the eggs were laid, begin to excavate fresh tunnels of their own.
Body or head louse. Lice spread such diseases as cholera, typhus, and relapsing fever.
At night, or when the skin is warm and moist, the mites may come out and wander about the skin. Although the potential rate of increase of the mites is enormous, most infested people usually have less than a dozen females.
The intense itching that characterizes the disease does not begin until a month or so after the parasites attack the host, when the skin has become sensitized; up to this time there is very little discomfort. After six weeks there is enough irritation to disturb sleep, and after about 100 days the itching may be continuous and almost unbearable. The lesions, or sores, where the mites have burrowed and the fingernails have ripped
away the skin, may get worse and often appear where there are no longer any mites, and secondary infections, such as impetigo, develop. Reinfections are especially uncomfortable, as the host is already sensitized.
Mites invade the skin of the wrists and hands most often. The head is rarely attacked. Most infections probably occur at night, from one bedfellow to another, although it is possible to get infected from a mangy animal.
The old standard treatment of "sulfur and lard" was used for many years. Now a single painting of the body from the neck down with a preparation containing benzyl benzoate emulsion is usually successful. A lindane ointment is also effective.
Prevention consists of avoiding contact with infected individuals and avoiding public towels and soiled bed linens. When scabies is introduced into a group of previously uninfected individuals (e.g., a crowded grade school) it may cause an extensive epidemic.
Redbugs or "Chiggers"
Almost anyone who has gone on a summer picnic or camping trip, especially if he was around a wild blackberry patch, has been introduced to the red bug, harvest mite, or "chigger." In some areas, in addition to the itching torment caused by its feeding activities, it may transmit a disease called scrub typhus. During World War II this disease caused more trouble in the Pacific area than any other insect-borne disease except malaria.
A malaria-carrying mosquito.
Chiggers are actually the six-legged larvae of mites, the adults of which are velvety, scarlet red arthropods, about as large as the head of a match, and do not feed upon vertebrates. Eggs of the chigger are laid on the ground. A few days after hatching, the larvae attaches itself to a vertebrate host, where it may remain attached from a few days to a month. They not only attack man, but feed upon lizards, turtles, rabbits, domestic animals, and birds.
The chiggers are anchored to the skin surface by a tissue reaction to the irritating saliva that is superficially
injected. The larva then drools into the skin; the saliva dissolves the skin tissue as it penetrates, finally forming a sort of tube in the skin, nearly as long as the body of the mite and filled with semi-digested tissue debris on which the mite feeds. The mites do not feed on blood, though their bright red color might give that
Irritation is largely due to the person becoming sensitized to the saliva injected. The itching is usually the worst 12 to 24 hours after the mites become attached. Some people develop an immunity, and the few reactive bites early in the season act as booster shots to revive this immunity.
Alcohol, camphor, or calamine lotion will reduce the itching. A good bath or shower soon after exposure to chiggers will cut down the number of bites and give some relief. Baking soda added to the bath water will help. Dusting sulfur in the stockings and on the legs will repel many of the mites.
Clothing may now be purchased that has been impregnated with repellants, such as diethyltoluamide, which will be effective for as much as six weeks.
Back in the days of log cabins, feather beds, attic sleeping quarters, and long red underwear, bedbugs were a rather common occupant of human habitations. They still persist in many parts of the world, although better housing, vacuum sweepers, and insecticides have greatly reduced their numbers in most areas.
Bedbugs are broad, flat, reddish brown insects. Though they have no wings they are fast runners. A peculiar, unpleasant odor from stink glands on their bodies cause some people to claim an ability to smell bedbugs if they are present in a home. This disagreeable odor is said to have been responsible for ancient peoples believing them to have a medicinal value, and some of the early literature contains instructions as to how to use bedbugs to cure such things as fainting spells, or to make hens immune to snake bites. Even today there are places in the world where they are used to treat fever and ague.
Gambusia aifinis, a tiny fish, is stocked in
ponds, wells, etc. to help control mosquito
populations by eating their larvae and pupae.
Pigeons may bring bedbugs to houses when they nest in the eaves or on the roof. Sparrows, starlings, and rats may also bring them into houses. Often exterminating campaigns to get rid of pigeons, sparrows, starlings, or rats are followed by human bedbug attacks; as their normal food supply is gone, they turn to the next meal available, the people in the house.
Bedbugs are normally night prowlers and are very "clever" at hiding in cracks in the daytime. If hungry enough they may come out and feed during the day. When feeding they usually cling to bedding or clothing, taking about 10 to 15 minutes to get a full meal, then returning to their hiding places.
A case of elephantiasis
These insects are able to go without eating for a long time. They have been kept alive without food for over a year.
As in the case of chiggers, the degree of irritation depends to a large degree on the development of hypersensitivity or eventual immunity. The irritation is produced by the salivary secretion, but when a feeding bug is undisturbed much of the secretion is redrawn with the blood meal and the irritation is lessened. (However, it is doubtful if many people would sit and let a bedbug finish its meal just to reduce the itching a little.) When bedbugs are allowed to continue to feed in large numbers on a human, anemia, nervousness, and insomnia may result.
Because bedbugs tend to "stay at home," they are not readily spread from home to home. They may be common in the upholstery of theaters, cheap motels and hotels, etc. The writer is familiar with one case where a young lady was severely bitten while sitting in an upholstered chair under a hair dryer in a beauty shop.
Prevention of "bugginess" consists principally of good housekeeping, though anyone may get them at some time or other. They are easily controlled by spraying or dusting with chlorinated hydrocarbons or organic phosphorus compounds. Fumigation of such large places as theaters and hotels may be necessary.
Allred, Donald M. 1960. Medical Arthropodology - A Laboratory Guide. Burgess Publishing Company, Minneapolis.
Armbrister, Trevor. 1963. Village Beyond Dispair. Saturday Evening Post. 236:66-9. Nov. 9.
Cameron, Thomas W. 1956. Parasites and Parasitism. Wiley, New York. 322 pp.
Chandler, Asa and Clark P. Read. 1961. Introduction to Parasitology. 10th edition. John Wiley and Sons, Inc.,
New York. 822 pp.
Cheng, Thomas C. 1964. The Biology of Animal Parasites. W. B. Saunders Company, Philadelphia. 727 pp.
Craig, Charles Franklin and Emest Carrol Faust. 1943. Clinical Parasitology. 3rd edition. Lea and Febiger, Philadelphia. 767 pp.
Noble, Elmer R. and Glenn A. Noble. 1961. Parasitology - The Biology of Animal Parasites. Lea and Febiger, Philadelphia. 769 pp.
Olsen, Oliver W. 1962. Animal Parasites: Their Biology and Life Cycles. Burgess Publishing Company, Minneapolis. 346 pp.
AUDUBON SCREEN TOURS
The Department of Biology presents the eighth Audubon Screen Tour Series in 1964-65. This series consists of five all-color motion pictures of wildlife, plant science, and conservation personally narrated by leading naturalists. All pictures are presented in Albert Taylor Hall at 7:30 p.m. on the dates listed below. Both group and single admission tickets are available; for further infomraiton write Dr. Carl W. Prophet, Department of Biology, KSTC, Emporia.
Allan D. Cruickshank, River of the Crying Bird, Sept. 30, 1964.
Emerson Scott, Our Changing Heritage, Oct. 21, 1964.
D. J. Nelson, Inherit the Wild, Dec. 4, 1964.
Walter H. Berlet, Northwest to Alaska, Jan. 8, 1965.
Roy E. Coy, Missouri Northwest, Feb. 4. 1965.
Those printed in boldfaced type are still available, free of charge except Poisonous Snakes of Kansas, which is sold for 25¢ per copy postpaid, to pay for the increased printing costs due to the color plates.
The out-of-print issues may be found in many school and public libraries in Kansas.
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