Economic Zoology Economic Zoology is a sort of applied applied zoology , which which involves the study study of animals animals / living organisms
that
are
of
benefit
or
those
that
cause
harm
to
humans
..
So , it is a specialized branch of zoology zoology which deals with animal world world that is associated with the economy , health ,and welfare of humans . Actually , animal world is related to economy by all means that we can count. The economic value value of an animal is generally accepted accepted as the amount of money people are willing to pay for it . n this modern world , perhaps it is the most popular way to assign value to thing . !ut , certainly , each each and every animal has has righteous values values and causes to live on the "other Earth with dignity . The value of biodiversity can be separated into two categories i.e. Ethical i.e. Ethical value or intrinsic value and E#trinsic value or anthropocentric value . Ethical value value or ntrinsic value is is based on a respect respect for life, a reverence reverence for the living world world and a sense of intrinsic value in nature and a concept of divine creation. t also defines the e#istence value of an animal being . E#trinsic value value of an animal , which can be more more clearly defined defined as Anthropocentri Anthropocentric c value , is comprised of direct and indirect economic benefit to humans . !iodiversity provides a range of goods, from agricultural crops to medicines and fibers, to which a direct value and cost can be assigned. This direct economic value of the natural environment can be divided into those associated with consumption and production i.e. $onsumptive use and %roductive use values. $onsumptive use value is usually assigned to goods consumed locally that are neither sought nor sold and therefore do not contribute to the economy of a country. %eople &living off the land' obtain the goods that they need for survival from the environment. Should the environmental (uality decline, for whatever reason, their standard of living would obviously deteriorate.
%roductive use values are assigned to those goods harvested from the environment, which are bought and sold locally, nationally or internationally. "a)or products include construction timber, fuel wood, fish and shellfish, fruits and vegetables and seaweed, to name a few. The value of these products is determined not by the final retail cost of the product but by the amount paid at the first point of sale less the e#penses to that point. ndirect
value
of
biodiversity
can
be
discussed
under
following
headings
*
Aesthetic value + butterflies, nudibranches, ornamental fishes, birds, mammals , all lives in the
wilderness
etc
$ultural value + in various tribes , many animals are regarded as sacred creatures Ecological value + many organisms are considered as bio-indicator, though each and every animal has more or less impacts on environments. n a broad sense, according to economic importance, animals can be categorized under following i.
divisions* Animals
ii. iii.
for
food
Economically
and harmful
Animals
of
products animals
aesthetic
importance
iv. Animals in scientific research Animals for food and products : "any animals are useful to man because of their value as food . Almost every phylum or animal group contains species that provide us with food or other important products . These animal groups include shellfishes + lobsters, shrimps, edible oysters , fish, turtles, frogs, birds and mammals . f course , we largely depend upon fish and domesticated bird and mammals
for
supply
of
meat
and
protein
food
.
owever , there are many other animals that are associated with food chain of our food supplying animals in the ecosystem. So, these animals indirectly help us in the production of food . Animal products that are more or less important , among these sponges, corals, shells of mollus0s, pearls, honey, wa#, sil0, shellac, feathers, wool, leather, bones etc are notable .
Economically harmful animals : 1umerous animals are directly or indirectly affect our health , community and other assets . They
can
be
predators
,
parasites
or
pests
.
"any predators attac0 or 0ill wildlife or our domestic animals . "any venomous animals can also be a threat to human . owever, these predators and venom bearers can be threat only when they are provo0ed . The parasites not only attac0 our wild fauna and domesticated animals but also can infect man . $oncisely, we can tell that parasitic creatures largely belong to %rotozoa, %latyhelminthes, 1ematoda and Arthropoda + particularly the insects and the arachnids Animals of aesthetic importance : "any animals and animal products are valuable to us in different ways . They are source of our recreation, decoration and other forms of )oy and pleasure. rnamental fishes, birds, reptiles, mammals are always in the centre of attraction to human. 2ife in the wilderness always offer heavenly beauty . Tropical rain forests , swamp forests , tropical wetlands/!ac0swamps, forests of tundra biome , deserts , prairies , coral reefs , deep blue seas are the real heavens of Earth and they can hardly be described by words . !esides , $ommunities of hobbyists are built up all over the world. !ecause of their enthusiasm, through selective breeding, many color variants / morphs of organisms become much popular in the hobby world .To describe a few , the astounding and )aw-dropping beauty , stri0ing coloration of several morphs of 3warf python + Python regius, glowing feathers +seems li0e they are painted by an artist of tiny little budgies + Melopsittacus undulatus or aristocrat movement of male Siamese 4ighter + Betta splendens
are
enough to ma0e a person love and get tangled with this colorful world. %ublic a(uariums, Zoos, Safari par0s are very much important now-a-days to ma0e the youth concern and feel about the wildlife that always remain entangled with man0ind with silence . Animals in scientific researches :
"any animals have been used and still be used for scientific researches . our 0nowledge in heredity and genetics are largely based on researches on Drosophila sp. or fruit fly. E#periments in animals have always been helped in understanding , most of the most of the physiological process. n medical science, surgery and drug effects are first observed on several animals such as rats, mon0eys etc . 5enerally , effectiveness of anti-venom serum is e#amined on horse . !esides , certain vaccines have been developed from animal serum . n present space research mon0eys, dog, toads, spiders etc have been used assess the effects of long space )ourneys . Glossary: Economic +ad). f or relating to the production, development, and management of material wealth, as of a country, household, or business enterprise. Economical +ad). ntended to save money, as by efficient operation or elimination of unnecessary features Economics i.e. the social science that analyzes the production,
distribution,
and
consumption of goods and services ntrinsic value i.e. an ethical and philosophic property. t is the ethical or philosophic value that an ob)ect has &in itself' or &for its own sa0e', as an intrinsic property. An ob)ect with intrinsic value may be regarded as an end or end-in-itself. E#trinsic value i.e. the value of ob)ects, both physical ob)ects and abstract ob)ects, not as ends-in-themselves but a means of achieving something else. t is often contrasted with items of intrinsic value.
PIROPLASMOSIS E(uine piroplasmosis is caused by the protozoan parasites Theileria equi +formerlyBabesia equi) and Babesia caballi, which is appro#imately twice the size of T. equi. E% affects horses, don0eys, mules, and zebras and sometimes dogs. The wild zebra
population is an important reservoir for the disease in Africa. Adult and nymphal tic0s are capable of transmitting the disease. 6hile obtaining a blood meal from an infected horse, the tic0 ingests infected e(uine red blood cells. As the erythrocytes are digested in the tic07s digestive tract, parasite trophozoites are released and undergo se#ual reproduction, resulting in the production of zygotes. Zygotes develop into sporozoites, which undergo division and spread via the tic07s haemolymph to its salivary glands. The causative agents are then transmitted when the infected tic0 bites a susceptible horse.
5enera of tic0s that transmit E% agents include Dermacentor, Hyalomma, Rhipicephalus, and Boophilus. Appro#imately 89 species of tic0s are capable of transmitting E% agents. nce infected, a horse can ta0e : to ;; days to show signs of illness. $linical signs of acute E% arenonspecific, and mimic many other diseases and conditions. Signs observed are the result of red blood cell destruction, complement activation, and release of inflammatory mediators +including brady0inin, histamine, and 9-hydro#ytryptamine. The severity of clinical signs reflects the number of cells destroyed and the degree of activation of the complement and inflammatory cascades.
Treatment via medication is instituted in affected horses. 3iminazene diaceturate, phenamidine isethionate, and amicarbalide diisethionate are effective in eliminating clinical
signs of B. caballi infection. !uparva(uone and other antitheilericidal drugs demonstrate some efficacy against T. equi, and may eliminate the parasite when combined with imidocarb. Theileria equi is more refractory to treatment than B. caballi, and higher dosages of imidocarb are re(uired. !ecause E% agents are transmitted by tic0s, tic0 control is a vital preventive measure. nfected horses must be (uarantined and isolated to reduce e#posure to tic0s. %ets and wildlife, including rodents must be prevented from entering the isolation area, as they may carry tic0s capable of transmitting E% agents. 1o vaccine is available. !EILERIASIS Theileriasis, also called east coast fever, is a tic0 born disease of cattle, sheep and goats caused by protozoan blood parasites, Theileria annulata, Theileria parva andTheileria ovis o the 5enus Theileria, 4amily Theileriidae and rder %iroplasmida. Animals are infected through the bite of vector tic0s. Tic0s possess large numbers of infective parasite Sporozoites, which develop in the salivary glands during the first two to four days of engorgement of nymph or adult tic0s. The first visible stages are found in lymphocytes and the infected lymph nodes shows an increase in mitotic figures. 6ithin ne#t several days parasites are increasingly apparent in the local nodes and elsewhere in the lymphoid and reticulo-endothelial tissue. $linical signs include loss of appetite, dullness, depression, high temperature, salivation, lacrimation, difficulties in breathing, anaemia, haemoglobinuria, )aundice, convulsion and death. ther symptoms include, enlargement of lymph glands, pale mucous membrane and nodules in the s0in, enlargement of liver, spleen, 0idney and gall bladder and presence of necrotic ulcers in the abomasums of stomach.
3iagnosis involves microscopic e#amination of blood with 5iemsa7s stain, presence of punched necrotic ulcers in abomasum of dead animal and serological test
Treatment is done by administering #ytetracycline, !erenil, Antihistamins and "ultivitamins. R"PA#OSOMIASIS Animal trypanosomiases include the following* $hagas% #agana or Animal African trypanosomiasis, also called &Souma' or &Soumaya' in Sudan< Surra< Mal de caderas of central South America< Murrina de caderas of %anama< (ourine< $ache)ial fe*ers
.aod/era or =hodesian trypanosomiasis< ahaga of camels in Algeria< Gal/ie,te or bilious fever of cattle or gall sic0ness of South Africa and Peste0+o+a of >enezuela. African animal trypanosomiasis +AAT is a disease comple# caused by tsetse-flytransmitted Trypanosoma congolense, T. viva!, or T. brucei in cattle but can cause serious losses in pigs, camels, goats, and sheep. nfection of cattle results in acute or chronic disease characterized by intermittent fever, anemia, occasional diarrhea, and rapid loss of condition and often terminates in death. n southern Africa the disease is widely 0nown as nagana, which is derived from a Zulu term meaning &to be in low or depressed spirits'? a very apt description of the disease. =uminants are widely 0nown to be active reservoirs of the trypanosomes. 6ild
E(uidae, lions,
leopards, and wild pigs are all susceptible
and can also serve as carriers of trypanosomes. f the three African animal trypanosomes, only T. viva! occurs in the
western emisphere in at least 8@ countries in the $aribbean and South and $entral America. n Africa, the primary vector for T. congolense, T. viva!, and T. brucei is the tsetse fly. These trypanosomes replicate in the tsetse fly and are transmitted through saliva when the fly feeds on animals. The three main species of tsetse flies for transmission of trypanosomes are "lossina morsitans, which favors the open woodland of the savanna< ". palpalis, which prefers the shaded habitat immediately ad)acent to rivers and la0es< and ". usca, which favors the high, dense forest areas. Trypanosomiasis is also mechanically transmitted by other biting flies of the genera Tabanus, Haematopota, #iperosia, $tomo!ys and %hrysops flies. nitial replication of trypanosomes is at the site of inoculation in the s0in, where swelling and a sore is caused. Trypanosomes then spread to the lymph nodes and blood and continue to replicate. T. congolense localizes in the endothelial cells of small blood vessels and capillaries. T. brucei and T. viva! localize in tissue. Antibody does not clear the infection, for the trypanosome has genes that can code for many different surface-coat glycoproteins and change its surface glycoprotein to evade the antibody. The cardinal clinical sign observed in AAT is anemia. 6ithin a wee0 of infection, there is usually a pronounced decrease in hemoglobin, red blood cell, and white blood cell levels, and within ; months these may drop to below 9@ percent of their pre-infection values. Also invariably present are intermittent fever, oedema and loss of condition. n the early phases of infection, especially with T. viva! and T. congolense, the parasite can readily be observed by microscopic e#amination of a wet-mount of blood slides. Thic0 blood films and stained with 5iemsa are also a good techni(ue. 4ly eradication and drug prophyla#is are effective trypanosomiasis control methods. Some of the older drugs such as the (uinapyramine derivatives Antrycide andAntrycide Prosalt are still used and give effective protection against T. brucei infection in horses, camels, and
cattle. The drug pyrithidium +romide is useful in the prophyla#is of T. viva! and T. congolense infections in cattle, sheep, and goats and can give protection for up to months. The most widely used of the newer drugs is isometamidium chloride.!omidium +romide has also been found to be an effective drug in Benya, and the newly introduced arsenical $ymelarsan is effective in treatment of T. brucei infection. A very widely used drug is dimina/ine aceturate, which is effective against all three African animal trypanosomes. The isometamidium drugs are also e#cellent chemotherapeutic agents as are the (uaternary ammonium compounds Antrycide1 Ethidium andProthidium2 1o vaccine is currently available for African animal trypanosomiasis. $O$$I(IOSIS
$occidiosis is the name given to a group of closely related diseases caused by a protozoan parasite called &imeria, which develops inside cells lining the intestine. As the parasites reproduce they cause bleeding and massive swelling of the gut. This leads to a huge loss of li(uid and the bird is unable to absorb the nutrients from its food. ut of 88 species of $occidia, the most common species are &imeria tenella, &. acervulina and &. ma!ima, which cause chronic intestinal coccidiosis.
&imeria tenella develops in the cells of the cecca which are the two blind sacs near the end of the intestine. t is one of the most pathogenic coccidia to infect chic0ens. &. necatri! develops in the small intestine and later in the caecum, within deeper tissues of the small intestine and is a ma)or pathogen of poultry. &. accervulina and &. ma!ima develop in epithelial cells, primarily in the upper part of the small intestine. The Sporozoite stage is the infective stage that contains special proteins and enzymes that allow it to penetrate the cell wall. nce inside the cell the sporozite begins its development through various stages. "ore parasites are produced during these stages, they
in turn move on and in to healthy cells to begun the cycle again. The result is wea0ened cell walls that allow moisture to lea0 and damaged blood vessels. This loss of blood and fluid is often fatal to the bird. $occidiosis is passed to another bird during the oocyst stage, which is an egg-li0e structure that is e#creted by the bird and can remain inactive for many wee0s and still infect another bird. The infection starts when an oocyst is ingested. nce ingested, symptoms may appear as early as C- days later. Symptoms of the disease include listlessness, lethargy, weight loss and blood in the droppings or elsewhere in the body, diarrhoea, and dehydration are all common signs of $occidiosis. The birds may also appear to have dirty or wet vents and may eventually die. A controlled dose of coccidial vaccine is administered once to day-old chic0s, initiating the development of natural immunity against &imeria. >accination eliminates the need for withdrawal times, which are re(uired when anticoccidials are used, as well as concerns about possible drug residues in poultry meat. >accination is also used to restore sensitivity to anticoccidials by replacing resistant, in-house strains of &imeria with drugsensitive &imeria strains.
LEIS!MA#IASIS 2eishmaniasis is primarily a zoonotic disease in which wild and domestic animals such as the fo#, )ac0al, rodents and wolves serve as reservoir hosts. ther animals in the surrounding areas can become infected and these are referred to as secondary or incidental hosts. The only proven vector of the #eishmania is the blood-suc0ing female sand fly of the genus Phlebotomus in the old world and #ut'omyia in the new world.>isceral leishmaniasis is caused by the parasites #eishmania donovani, #eishmania inantum and #eishmania
archibaldi in the old world and by #eishmania chagasi in the new world.
The sand fly vector becomes infected when feeding on the blood of an infected individual or an animal reservoir host. The parasites live in the macrophages as round, nonmotile amastigote fiorm +D-: micrometers. The macrophages are ingested by the fly during the blood-meal and the amastigotes are released into the stomach of insect. Almost immediately the amastigotes transform in to a motile, elongated +8@-;@ micrometers, flagellate promastigote form. The promastigotes then migrate to the alimentary tract of the fly, where they multiply by binary fission. 4our to five days after feeding, the promastigotes move forward to the proboscis of the insect. 6hen the sand fly ne#t feeds on a mammalian host, it7s proboscis pierces the s0in and saliva containing anti-coagulant is in)ected into the wound to prevent the blood from clotting, the promastigotes are transferred to the host along with the saliva. nce in the host the promastigotes are ta0en up by the macrophages where they rapidly revert to the amastigote form. The leishmanias are able to resist the microbiocidal action of the acid hydrolases released from the lysozymes and so survive and multiply inside the macrophages, eventually leading to the death of the macrophages. The released amastigotes are ta0en up by the additional macrophages and so the cycle continues. ltimately all the organs containing macrophages and phagocytes are infected, especially the spleen, liver and bone marrow. $ommon symptoms include high undulating fever often with ;-D pea0s in ;C hours and drenching sweats which can easily be misdiagnosed as malaria< $hills, rigors, weight loss, fatigue, poor appetite, cough, burning feet, insomnia, abdominal pain, )oint pain,
anore#ia, epista#is and diarrhoea. $linical sings include splenomegaly, hepatomegaly and lymphadenopathy. The two pentavalent antimonial compounds, sodium sti+ogluconate andmeglumine antimoniate have been used as first-line chemotherapeutic agents against all forms of leishmaniasis including visceral leishmaniasis. f treatment with pentavalent antimonials is unsuccessful a preparation of an aromatic diamidine1 pentamidine isethionate 3Pentamidine4 or pentamidine dimethane sulphonate 3Lomidine4 is used.Amphotericin -1 which is a macrolide, is another drug of second choice used in the treatment of leishmaniasis. There are three preparations of lipid associated Amphotericin ! currently under trial for treatment of leishmani asis* Am-isome +>estar, SA, Amphocil+2iposome technology nc, SA and Amphotericin - lipid comple) +!ristol "eyers S(uibb, SA.
Types of parasites The major types of organisms that cause parasitic infections include species of protozoa, helminths or worms, and arthropods. Protozoa. Protozoa
are single-celled organisms that carry out most of the same physiological
functions as more complex organisms. More than 45, species of protozoa are !nown, many of which are parasitic. "s parasites of humans, this group of organisms has historically #een the cause of more suffering and death than any other category of diseasecausing organisms. $ntestinal protozoa occur throughout the world. They are especially common in areas where food and water sources are su#ject to contamination from animal and human waste. Typically, protozoa that infect their host through water or food do so while in an inacti%e state, called a cyst. " cyst consists of a protozoan encased in a protecti%e outer mem#rane. The mem#rane protects the organism as it tra%els through the digesti%e tract of a pre%ious host. &nce inside a new host, the parasite de%elops into a mature form that feeds and reproduces.
"me#ic dysentery is one of the most common parasitic diseases. $t often afflicts tra%elers who %isit tropical and su#tropical regions. The condition is characterized #y diarrhea, %omiting and wea!ness. $t is caused #y a protozoan !nown as Entamoeba histolytica. "nother protozoan that causes se%ere diarrhea is Giardia lamblia. This organism was originally disco%ered #y 'eeuwenhoe! and has #een well-pu#licized as a parasite that can infect hi!ers who drin! untreated water.
Other types of parasitic protozoa infect the blood or tissues of their hosts. These protozoa are typically transmitted through another organism, called a vector. A vector is an organism that carries a parasite from one host to another host. In many cases, the vector is an invertebrate, such as an insect that itself feeds on a host and then passes the protozoan on through the bite wound. Some of the most infamous of these protozoa are the ones that cause malaria and African sleeping sickness. Hosts
"iardia infects humans, but is also one of the most common parasites infecting cats, dogs and birds. "ammalian hosts also include dozen of species, F9G including cattle, sheep,FG andgoats.FG
