Parasitology 2: Biology of Parasitism
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Questions and Answers

What characterizes Simple Metamorphosis in ticks?

  • Ticks have distinct color changes throughout their life stages.
  • All life stages display significant morphological differences.
  • All life stages look similar except for size and minor differences. (correct)
  • Ticks undergo complete metamorphosis with distinct larval and pupal stages.

What stage of tick development follows the 1st Nymph?

  • 2nd Nymph (correct)
  • Adult Female
  • Larvae
  • Adult Male

How many hosts does Dermacentor variabilis, a common tick species, usually feed on?

  • 4
  • 3 (correct)
  • 2
  • 1

What happens to engorged female ticks after they feed?

<p>They drop off the host to deposit eggs in the environment. (D)</p> Signup and view all the answers

What is the leg count of larvae compared to that of nymphs and adults?

<p>Larvae have six legs; nymphs have eight; adults also have eight. (A)</p> Signup and view all the answers

What is the primary characteristic of a definitive host?

<p>It is infected by the sexually mature parasite. (B)</p> Signup and view all the answers

Which type of host is considered a transport host?

<p>Paratenic host (A)</p> Signup and view all the answers

What does the prepatent period refer to?

<p>The time from infection to the production of offspring. (B)</p> Signup and view all the answers

Which parasite characteristics indicate high host specificity?

<p>It only infects one or a few host species. (B)</p> Signup and view all the answers

Which factor distinguishes a biological vector from a mechanical vector?

<p>It is necessary for the pathogen's development. (D)</p> Signup and view all the answers

What stage do Free-living Larvae develop into after hatching from ova?

<p>Infective Larvae (L3) (C)</p> Signup and view all the answers

What happens to Infective Larvae after they are ingested by the Definitive Host?

<p>They become Arrested Larvae. (B)</p> Signup and view all the answers

Which organism is responsible for transmitting Trypanosoma cruzi?

<p>Triatomine bugs (B)</p> Signup and view all the answers

What is a consequence of Trypanosoma cruzi's tropism for cardiac muscle?

<p>It causes damage to the heart. (A)</p> Signup and view all the answers

What type of life cycle does Trypanosoma cruzi exhibit?

<p>Indirect Life Cycle (A)</p> Signup and view all the answers

What condition do larvae and adult worms primarily cause in the abomasal mucosa?

<p>Dysfunction (D)</p> Signup and view all the answers

Which of the following describes the state when larvae are inactive until environmental conditions improve?

<p>Hypobiotic larvae (C)</p> Signup and view all the answers

What is the main consequence of protein catabolism in infected hosts caused by these parasites?

<p>Weight loss (C)</p> Signup and view all the answers

Which type of larvae are known to be infective?

<p>Infective larvae (C)</p> Signup and view all the answers

What does high host specificity in pasture-borne parasites indicate?

<p>Parasites have a narrow range of hosts (B)</p> Signup and view all the answers

What is a common clinical sign seen when environmental conditions are right for parasite activity?

<p>Diarrhea (A)</p> Signup and view all the answers

Which life cycle type do many pasture-borne parasites, including Ostertagia spp., possess?

<p>Direct life cycle (C)</p> Signup and view all the answers

What is often the initial developmental stage of these parasites before they become infective?

<p>Free-living larvae (D)</p> Signup and view all the answers

What is the primary characteristic of Simple Metamorphosis in lice development?

<p>Life stages differ only in size. (A)</p> Signup and view all the answers

Which of the following stages do lice develop through?

<p>Nits, Nymphs, Adults (B)</p> Signup and view all the answers

What do Sucking Lice primarily feed on?

<p>Blood (A)</p> Signup and view all the answers

What is the role of the female louse regarding the eggs?

<p>She cements them to the host's hair or feather shaft. (B)</p> Signup and view all the answers

What is a common outcome of infestation by Chewing Lice?

<p>General irritation and pruritus. (B)</p> Signup and view all the answers

Which term accurately describes the eggs of lice?

<p>Nits (B)</p> Signup and view all the answers

How is host specificity classified for lice?

<p>High specificity. (A)</p> Signup and view all the answers

Which characteristic differentiates Hemimetabolous development from Holometabolous development?

<p>All life stages are similar in appearance. (C)</p> Signup and view all the answers

What type of life cycle do pinworms exhibit?

<p>Direct Life Cycle (D)</p> Signup and view all the answers

What is the definitive host of Oxyuris equi?

<p>Horses (A)</p> Signup and view all the answers

Which of the following terms describes a disease that is transmitted from animals to humans?

<p>Zoonosis (C)</p> Signup and view all the answers

Which symptom is primarily associated with infection from Oxyuris equi?

<p>Pruritus of the perianal region (D)</p> Signup and view all the answers

How does fecal-oral transmission relate to Direct Life Cycles?

<p>It is integral to their completion. (C)</p> Signup and view all the answers

What host specificity level do pinworms have?

<p>High (A)</p> Signup and view all the answers

Which statement about pinworms is true?

<p>They can cause alopecia in hosts. (D)</p> Signup and view all the answers

Which parasite stage is NOT present in the life cycle of pinworms?

<p>Intermediate (B)</p> Signup and view all the answers

Flashcards

Definitive Host

The animal host where the sexually mature parasite lives and reproduces.

Intermediate Host

The host where a parasite's immature larval stages develop further.

Prepatent Period

Time between infection and parasite reproduction.

Host Specificity (High)

A parasite's ability to infect only a limited number of host species.

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Biological Vector

A vector required for a parasite's life cycle development.

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Direct Life Cycle

Parasite life cycle where infective larvae directly infect the host without intermediate hosts.

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Zoonosis

An animal disease that can be transmitted to humans.

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Direct Life Cycle

A parasite life cycle that involves a single host.

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Pasture-borne Parasites

Parasites that are found in pastures and can infect animals.

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Fecal-oral transmission

Transmission of a parasite through contact with contaminated feces.

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Larvae and adult worms

Immature and mature stages of the parasite, causing abomasal damage.

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Parasite Stage

Different forms of the parasite during its lifecycle.

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Abomasal Mucosa Dysfunction

Damage to the lining of the abomasum, leading to digestive problems.

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Clinical Signs

Observable symptoms like diarrhea, anorexia, signifying a problem.

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Oxyuris equi

Horse pinworm.

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Host Specificity

A measure of the parasite's preference for a specific host.

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Infective Larvae

Immature parasite stages capable of infecting a host.

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Host Specificity

The degree to which a parasite infects specific host species.

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Pinworms

A type of parasitic worm.

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Free-living Larvae

The early stage of a parasite that lives independently in the environment, typically in soil or water.

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Arrested Larvae

The stage of a parasite's development that is paused or inactive within the host's body. It's also known as Hypobiotic Larvae.

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Trypanosoma cruzi

A protozoan parasite that causes Chagas disease and is transmitted by triatomine bugs.

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Tick Life Cycle

Ticks go through four stages: egg, larva, nymph, and adult. Each stage requires a blood meal to develop and molt into the next stage. Adult females lay eggs after mating, starting the cycle again.

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Host Specificity in Ticks

Some ticks are known as "3-Host Ticks" because each stage (larvae, nymph, and adult) feeds on a different host. Other ticks may be "1-Host" or "2-Host".

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Simple Metamorphosis

Insects with simple metamorphosis have similar-looking life stages, only differing in size or minor features. Ticks are an example.

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Engorged Female Tick

After feeding, females grow larger than males because they need to lay eggs. An engorged female drops off the host to lay eggs in the environment.

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Zoonotic Ticks

Ticks that can transmit diseases from animals to humans are called zoonotic ticks.

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Life cycle types

There are two basic life cycle types for arthropods: Simple Metamorphosis and Hemimetabolous. Simple metamorphosis means all life stages look similar, except for size, while Hemimetabolous development involves distinct nymph stages.

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What is a louse?

A louse is a type of insect parasite that feeds on the skin, feathers, or fur of animals, including humans. Chewing lice eat skin and debris, while sucking lice feed on blood.

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What are nits?

Nits are the eggs of lice, cemented to the hair or feathers of the host.

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What is Simple Metamorphosis?

In Simple Metamorphosis, all life stages of an arthropod look similar, except for size. Adults develop directly from nymphs.

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What is Hemimetabolous development?

Hemimetabolous development is a type of arthropod life cycle where nymphs go through molting stages to become adults. Each nymph stage looks different from the previous one.

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Why is host specificity important?

Host specificity refers to the degree to which a parasite infects specific host species. High host specificity means the parasite can only infect a limited number of species, while low host specificity means it can infect a wider range of species.

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What does zoonotic mean?

A disease is considered zoonotic if it can be transmitted from animals to humans.

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How do lice reproduce?

Male and female lice mate on the host, and the female lays eggs (nits) on the hair or feathers. These nits hatch into nymphs, which eventually become adults.

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Study Notes

Parasitology 2

  • Covers the biology of parasitism
  • Slide deck credit: NC State Veterinary Parasitology Group (VMP 930)

Parasite Groups

  • Protozoa:
    • Hemoflagellates (in blood)
    • Mucoflagellates
    • Coccidia
    • Piroplasms (in blood cells)
  • Helminths:
    • Trematodes (flukes)
    • Cestodes (tapeworms)
    • Nematodes
    • Acanthocephalans
  • Arthropods:
    • Ticks
    • Mites
    • Lice
    • Fleas
    • Flies

Infectious Diseases

  • Microbiology:
    • Virology
    • Bacteriology
    • Mycology
  • Parasitology:
    • Protozoology
    • Helminthology
    • Entomology

Types of Life Cycles

  • Direct life cycle: Parasite does not require an intermediate host. The infective stage is in the environment (egg, cyst, larva).
  • Indirect life cycle: Parasite requires an intermediate host.
    • Facultative indirect life cycle: Parasite may use a paratenic host, but it is not necessary.

Parasite Stages

  • Various terms for stages. Examples include larval, adult stages for worms, protozoa, and arthropods.

Hosts

  • Definitive host: Primarily infected by sexually mature parasite.
  • Intermediate host: Infected by larval stage(s). Development continues, but doesn't mature in these hosts.
  • Vector: Organism that transmits a pathogen between hosts.
    • Mechanical vector: Doesn't need development of the pathogen.
    • Biological vector: Needs the pathogen to develop.
  • Paratenic host: Infected by a larval stage which does not develop further.
  • Aberrant host: Accidentally infected, but doesn't transmit the parasite, also called a dead-end host

Other Concepts

  • Host Specificity:
    • High: Parasite infects only a few or one host species.
    • Low: Parasite infects many or several species.
  • Prepatent Period (PPP): Time between infection to the production of offspring.
  • Patent: Infection where sexually mature parasites generate offspring.
  • Zoonosis: Animal disease transmitted to humans.

Helminth Life Cycles (Oxyuris equi, Physaloptera rara, Ostertagia ostertagi, Trypanosoma cruzi, Giardia canis, Cystoisospora spp., Dermacentor variabilis, Trichodectes canis, Ctenocephalides felis)

  • Life cycle types: direct, indirect, etc. Description of parasite's life stages (eggs, larvae, pupae, adults, etc.) in each host and their stages in the environment. Key info like hosts involved (definitive, intermediate, reservoir/paratenic).
  • Host Specificity: Examples: high (infect only a few hosts), moderate, low (relatively few, or many hosts infected)
  • Zoonotic: yes or no (can infect humans)

Parasite Pathogenesis

  • Factors that cause disease: trauma, nutrient robbing, excretion of toxins. Hosts response; infection processes (inflammation, etc.) are also important aspects of pathogenesis.

Parasite Impact on Host

  • Continuum from no effect to disease. Different levels include subclinical, no effect, subclinical (no obvious symptoms). disease (symptoms evident).
  • Clinical judgment regarding treatment necessity.

Distribution of Autoimmune Disorders and Helminths

  • Epidemiological data show a correlation between developing countries and lower incidence of autoimmune diseases vs higher parasitic worm infection. Developed countries have much lower parasitic infections incidence but much higher autoimmune diseases incidence.

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Related Documents

Biology of Parasitism Part 2 PDF

Description

Explore the fascinating world of parasitism in this Parasitology 2 quiz. Delve into the biology of various parasite groups including protozoa, helminths, and arthropods, along with their life cycles and stages. This quiz is based on lectures from the NC State Veterinary Parasitology Group.

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