INTRODUCTION The living organisms frequently associate together, often closely. There are a ...

215 Pages·2016·10.4 MB·English

INTRODUCTION
The living organisms frequently associate together, often closely.
There are a number of "motives" for these associations, including
protection, nutrition and as an aid to the dispersion (both
geographically and temporally) of the organism. There are four main
ways that animals of different species may be associated together;
Symbiosis, Mutualism, Commensalisms and Parasitism.
Many biologists see in a parasite a form of predatory animal.
Instead of killing and devouring its prey whole, it can, by virtue of its
smaller size, live on the host or in it, and eat it little by little. In nature
we find extremely varied and diverse types of parasitism.
In parasitism they associates live either partly or wholly at the
expense of the other associate, the other partner (the host
organism) not gaining anything from the association. This association
may give rise to extreme pathology in the host, or the parasitism may be
generally not very pathogenic. These parasites are an organism living in
or on another living organism, obtaining from it part or its entire
organic nutrient, commonly exhibiting some degree of adaptive
structural modification and causing some degree of real damage to its
host. Organisms in these associations may either be on the outer
surface of the host organism (Ectoparasites) or inside the host organism
(Endoparasites). Parasites may also be classified according to the
closeness of the relationship as Facultative Parasites, the parasitic
lifestyle taken up opportunistically, whereas in Obligate
Parasites, organism must parasitize another organism. These parasites
may often cause diseases; in this case they are referred to as Pathogenic
Parasites. In a somewhat wider interpretation of the term parasitism
some organisms exhibit parasitic behaviour only early in their lifecycle,
these being referred to as Brood parasites.

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INTRODUCTION
Parasitic helminths may have either simple or complicated
lifecycles. The adult parasites are found in the definitive host where the
parasite's sexual cycle usually takes place, with either cross or self
fertilization with hermaphroditic parasites, or sexual reproduction if the
parasites have separate sexes, followed by production of eggs, or more
rarely with viviparous helminths, larvae. In many cases the parasite
larvae are found in different hosts, these are called the intermediate
hosts. Parasitic helminth larvae may have one, two or more
intermediate hosts in their lifecycles, or they may have no intermediate
hosts. Often asexual stages of reproduction occur in these intermediate
hosts, (for example with platyhelminth parasites). The two terms
definitive and intermediate host are the most important in parasitology
when referring to the type of host.
Parasitic helminths or worms comprise a diverse group of
metazoan organisms that infect billions of people and their
domesticated animals worldwide (Colley et al., 2001). In large part,
helminthiasis is caused by members of the phyla Nematoda and
Platyhelminthes (Kennedy and Harnett, 2001). Species belonging to
both the phyla occupy numerous niches within their mammalian hosts,
ranging from intestinal lumen to intravascular and even intracellular
sites. While the majority of individuals infected with parasitic worms
experience relatively minor symptoms compared to those infected with
organisms that typify more acute viral or bacterial infections, a small
percentage suffer severe life-threatening consequences. Since the overall
prevalence of helminthiasis is so high, relatively low frequencies of
severe disease nevertheless equate to large numbers of people
experiencing infection associated morbidity.

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The parasitic disease have posed a complex problem and become
a great challenge to the parasitologists in the world today, coupled with
the rapid changing world; the changes in the human ecology and the
effect of climatic changes on parasitic system have further increased the
threat to human as well as animal’s life.
In parasitic infections where the association is much closer, are
generally less pathogenic, extreme pathology generally only being
associated with high parasitic load. Study of helminth parasites of
vertebrates have a great practical as well as scientific value directly
related to the welfare of human beings. Frogs and toads harbor many
adult parasites including nematodes and their larvae. The remarkable
changes in the living conditions of host body influence the helminth
fauna, which exist within their body. Acaudated amphibians are final
hosts for a great number of parasitic nematode species; they are
interesting as a source of infestation for many wild and domestic
animals (birds, mammals) because they are osculant hosts for the larval
stages of the development of many nematode species.
The host and its parasites constitute a community of organism
living in close intimacy and exerting a profound effect upon each other.
These anurans are susceptible to many parasitic infections. They
display a luxuriant nematode fauna in the major part of their
alimentary tract. In fact helminth parasites constitute the bulk of
parasitic infections within their host body.
Nematodes represent one of the most important groups of
metazoan parasites of vertebrates. Some of them are known to be the
agent of serious diseases of domestic and wild animals represents an
important public health problem. However in addition to their practical
importance the nematodes also represent a significant model for the

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INTRODUCTION
solution of a number of theoretical questions concerning host-parasite
relationships, biology, ecology, zoogeography and phylogeny of these
parasites and their hosts as well as questions of general biology. The
present knowledge of parasitic nematodes is still incomplete,
particularly in regard to their biology and ecology.
Nematodes play a significant role in the economy of man and
animals. Many species are zoonotic in nature capable of transmission
between humans and animals. They are successfully adapted to a
variety of habitats and are widely distributed as free living forms in
different terrestrial and aquatic habitats. They are also found parasitic
in several hosts, both plants and animals including man. Nematodes
parasitic in vertebrates show a wide range of adaptability. In these
hosts the worms are usually found in the alimentary canal. However
they may be found in the body cavity, lungs, heart, blood vessels,
urinogenital system etc. very often they also found in the connective
tissue, serous membrane, oral, nasal and orbital cavities. Their larvae
usually encysted have been found unrestrictedly distributed in the host
body. Many species of nematodes cause acute pathogenicity and misery
to humans as well as animals.
Nematode infection causes the skin on the thighs to become
rough and flaky. As this infection progress the entire body will be
affected. Nematode infection is highly contagious, especially among
frogs that are under a large amount of stress.
The class Amphibia includes frogs, toads, salamanders, newts
and caecilians. Amphibians are characterized by a glandular skin
without external scales, by gills during development (and in adulthood
in some), and by eggs that may have jelly coats but develop without
formation of extraembryonic membranes such as the amnion. Most

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INTRODUCTION
amphibians also have four limbs. Limbs and lungs are adaptations for
life on land; the limbs evolved from the ancestral fishes' lobed fins. The
scales and amniotic egg evolved by reptiles are further adaptations for
life on land and distinguish reptiles from amphibians.
They are very important to humans and also important to the
food chain. More than 73 amphibian species are known to have some
kind of medicinal values. The skin of frogs and toads has been used for
medicine by many cultures since ancient times. For example, in the
Korean culture during burning Japanese Tree frog (Hyla japonica) oil
was believed to heal wounds, whereas the Gold-spotted Pond
Frog (Rana plancyi chosenica) has been prescribed for fever, weakened
immune system and to cure infectious diseases from wild
animals. Each amphibian species has its own protective compounds
against predators and microorganisms. Compounds include amines,
alkaloids and peptides. They play as poisons, antibiotics and pain
relievers. Several hundred of amphibian antimicrobial peptides have
been isolated from amphibian species. Peptides may be active against a
broad spectrum of pathogens and have significant potential application
for our health and conservation of other species. For instance, the
peptide caerin 1.1 from Litoria caerulea inhibits growth of cancer cells,
viral infection of target cells, prevents growth of malaria parasite and
kills nematodes. Amongst the known alkaloids found in frogs, the
alkaloid epibatidine from the endangered Ecuadorian frog Epipedobates
tricolor is a potent non-addictive analgesic considered to be 100 to 200
times more effective than morphine.
In many countries, amphibians are still used in traditional
medicines often to meet primary health needs. More than 30 species of
amphibians have been recorded in traditional Chinese medicine alone.

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In Korea, a commercial medicine for athlete’s foot is made from toad
skin secretions. In Mexico, the endangered Axolotal Ambystoma
mexicanum is believed to provide remedies for respiratory aliments such
as bronchitis. Loosing more amphibian species (lost about 100 species
already!) would have terrible impacts on our current and future
applications for human health.
Amphibians are one of the main links in many ecosystem food
webs. Often unseen, they can be quite abundant in some habitats. In
temperate and tropical regions, amphibian can exceed all other
terrestrial vertebrates such as birds, mammals and reptiles.
Amphibians including their larvae are important predators of
invertebrates. Removal of amphibians from particular habitat can have
drastic consequence by increasing insect population. Through
metamorphosis, many species of frogs and salamanders are a link to
the transfer of nutrient from aquatic systems to terrestrial ones.
Therefore, removing amphibians from a particular habitat can
affect drastically algae communities, invertebrate population, predator
dynamics, leaf litter decomposition and nutrient cycling. Preserving
amphibian diversity is an important component for living in a healthy
environment.
Frogs and toads are one of the most important components of
ecosystem which are abundant in nature and help to maintain the
balance of nature like other amphibians. Man is a direct predator of
these animals in different parts of the globe, consume its meat and dry
it for food markets and use as experimental animals. Frog’s legs form
the staple food in some parts of the world. Not only in India, the export
of frog’s leg a major trade. Most of the toads secrete a poison which
acts as a harsh irritant to the mouths of predators. Its body secretion

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INTRODUCTION
use to poison arrowhead. These animals also preyed by many
carnivorous fishes, reptiles, birds, mammals and thus form a major
nutritional source for them. It also acts as a predators of insects, pests
and destroy a large number of insects mainly mosquitoes. So the
numbers of amphibians are directly related to the control measures of
insects and pest by biological control and thus they keeping the insect
population in check and maintain a balance in nature.
Frogs and toads are also used in laboratories for dissection and
study purpose in biology subject. The larvae afford excellent materials
for the study of embryology and endocrinology. The health of frogs and
toads are closely linked to the health of environment and these animals
are early indicators of significant environmental changes that may
otherwise go undetected by humans. Thus they are considered for their
economic importance and having zoonotic importance too. They also
serve as intermediate, complementary or reservoir hosts for some of the
helminthes infecting domestic and wild animals.
Moreover a considerable amount of work has been done on the
seasonal occurrence and abundance of parasites in fishes, birds and
mammals but the helminth parasites of toads and frogs have not
received adequate attention as they are not considered to be of any
significant economic importance. Several species of frogs have been
examined for helminth parasites but there is no information on long
term parasite population changes. Keeping in view the economic values
to human survival, their variety along with the diversity of nematode
parasites and its importance from biodiversity point of view, this work
has been undertaken as an utmost necessity.
In last two decades a region wise and host wise systematic study
of nematode parasites was taken up in various places but the

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INTRODUCTION
biodiversity of macro parasitic infection mainly by nematode parasites
in anurans from Marathwada region is unexplored and the knowledge
in this concern is almost lacking. No record on the nematode infections
in these amphibians in the industrial areas surrounding the
Aurangabad region like Waluj, Ranjangaon, Shendra, and Chikalthana.
Prevalence of parasitic nematodes of toads and frogs of these localities
were compared among themselves which are climatically not so different
regions in Aurangabad. Since literature on nematode infections,
taxonomic importance and its diversity in frogs and toads in the study
areas are almost lacking, hence the present work is of considerable
importance.
Thus the taxonomic status, species richness, diversity and
knowledge of nematode parasites are augmented by undertaking the
current work. As there was no previous records of such work on
diversity of nematode parasites in Maharashtra especially in
Marathwada region.

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LITERATURE SURVEY

The nematodes are common parasites encountered more or less in
every vertebrate host. The study on amphibian nematodes in
Maharashtra, India and also from all over the world has been reviewed
time to time. It is true that quite a considerable work has been done on
the taxonomy and morphology of this group in everywhere except this
Marathwada region, Maharashtra state where the work on nematode
parasite in toads and frogs are meager. The study of amphibian
nematodes in India and neighbouring countries (South Asia: Bangladesh,
Sri Lanka, Myanmar, Nepal and Pakistan) are rather poor and scanty
than the other parts of the globe.
Oerley (1882) reported nematode parasites with a review of the
classification of the order in British Museum. Linstow (1904) worked on
nematodes from the Colombo Museum.
In 1915 Lane investigated Oxysoma falcatum Von Linst, 1906a and
described Falcaustra falcate. Railliet and Henry (1915a) discussed the
species of the genus Camallanus. An ecological study of the helminth
parasites of amphibians along with other hosts in Western
Massachusetts and vicinity were made by Rankin in 1945.
Skrjabin (1916) recorded the result of collection of nematodes from
the expedition of Dogiel and Skolow in British East Africa and Uganda.
Steiner described Aplectana Kraussei n.sp. in 1923 and in next year
(1924) recorded nematodes from alimentary tract of the Carolina Tree
frog (Hyla carolinensis Pennant) in Pacific Ocean.
Travassos (1917) established the genus Oswaldocruzia from Brazil
in South America. In 1918 he worked on family Kathlamidae Lane and
genus Falcaustra. In 1931 they worked on family Cosmocercidae. Their
contributions on nematodes of amphibian hosts were mentioned in 1919,
1920 and 1925. In 1923a they mentioned Oxuyoridea–Kathlanidae,
Oxyuroidea-Oxyuridae and Oxyuroidea-heterakidae. In 1926 they
described Rhabdias filleborni and in 1930 they discussed Rhabdias oidea

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