ectoparasites

What are ectoparasites?

Parasites that are attached to the skin or temporarily invade the superficial tissues of the host's body.

What phylum do ectoparasites belong to?

Ectoparasites are arthropods, which belong to the phylum Arthropoda.

What is the defining characteristic of arthropods?

Arthropods have jointed legs, chitinous exoskeletons, and segmented body parts.

What is the term for the invasive behavior of ectoparasites on a host's integument?

Infestation.

What is required for an organism to be classified as a true ectoparasite?

It must have an intimate relationship with the host.

Why are mosquitoes not considered ectoparasites?

Mosquitoes do not live on humans; they only visit for a blood meal.

What are the two main classes of arthropod ectoparasites?

Insects (Insecta) and arachnids (Arachnida).

What are the characteristics of insects?

Insects have 6 legs, a body divided into a head, thorax, and abdomen, and may have one, two, or no pairs of wings.

What are the characteristics of arachnids?

Arachnids have 8 legs and are wingless, including spiders, mites, ticks, scorpions, and pseudoscorpions.

What is a habitat-specific parasite?

A parasite that can live in only one specific location on or in its host.

What is a host-specific parasite?

A parasite that can live and reproduce on only one species of host or a group of closely related hosts.

How do insect ectoparasites typically survive?

They survive off the blood of their hosts, although some also eat skin, hair, and other secretions.

What are some typical adaptations of insect ectoparasites?

Loss of functional wings, flattening of the body, strong legs and claws for clinging, and biting or sucking mouthparts.

What is the order of fleas?

Order Siphonaptera.

What diseases can fleas vector?

Bacteria, protozoa, viruses, and tapeworms.

What is the order of lice?

Order Phthiraptera.

What is unique about lice compared to other ectoparasites?

Lice spend their entire lives on the host and are highly host-specific.

What is the life cycle type of lice?

Hemimetabolous (incomplete metamorphosis).

What do lice feed on?

Epidermal tissue debris, parts of feathers, sebaceous secretions, and blood.

What adaptations do lice have for survival as permanent ectoparasites?

They possess stout legs and claws for clinging tightly to fur, hair, and feathers.

What is the size range of lice?

Lice are about 0.5-8 mm in length.

What happens during the life cycle of lice?

Eggs are laid on the host, and immature lice (nymphs) also live on the host, growing and molting as they develop.

What is the process called when an insect sheds its skin?

Molting.

What happens to a nymph after each moult?

It looks a bit different or bigger, and after the final moult, the full adult form emerges.

What are the three types of lice that infest humans?

1. Crab louse (Pthirus pubis) - infests the pubic region. 2. Head louse (Pediculus humanus capitis) - prefers the head. 3. Body louse (Pediculus humanus humanus) - infests clothing on the body.

What is the common name for Pthirus pubis?

Pubic louse or crab louse.

What are the characteristics of adult crab lice (Pthirus pubis)?

Adults are 1.5 to 2 mm long, have a short, wide body, and the last two pairs of legs are larger for attachment to human hair.

What are the life cycle stages of the crab louse?

Nit (egg) and adult crab louse.

What disease is associated with body lice and what bacterium causes it?

Louse-borne typhus, caused by Rickettsia prowazekii.

What are the symptoms of typhus fever?

High fever, body rash, and CNS destruction.

What factors predispose humans to pediculosis?

Poor hygiene, close personal contact, severe itching, and scarred, hardened skin.

What insecticide was used during WWII for delousing?

DDT dust.

What modern treatments are used for lice control?

Lotions or shampoos containing Permethrin, such as 'Rid'.

What are the common hosts for fleas?

Rodents, bats, carnivores, and rabbits.

What is the scientific name for the human flea?

Pulex irritans.

What are the effects of flea bites on hosts?

Inflammation, pruritus (itching), or anemia.

What is the vector for plague?

Fleas, specifically those infected with Yersinia pestis.

What is the life cycle of a flea?

Egg hatches into a larva, then inactive pupa stage, and finally into an adult.

What type of metamorphosis do fleas undergo?

Holometabolous (complete metamorphosis).

What do flea larvae feed on?

Debris, such as feces produced by the host animal.

How do fleas typically interact with their hosts?

Adult fleas live in temporary association with their host, feeding on blood.

What is a common characteristic of flea morphology and behavior?

They are flattened, wingless, and spend most of their time on the host.

What are the implications of flea mobility?

Fleas can easily move between hosts, making them significant parasites in medical and veterinary contexts.

What is a common control measure for lice and fleas?

Good personal hygiene and laundering of clothes in hot water.

What is the scientific name of the cat flea?

Ctenocephalides felis

What attracts fleas to their hosts?

Carbon dioxide and body heat

What historical event was the Oriental flea associated with?

The Black Death, which killed 1/3 of Europeans between 1347 and 1352.

How do fleas transmit bacteria that cause plague?

Bacteria multiply rapidly in the flea's digestive tract, causing blockages that lead to regurgitation of infected blood into the bite wound.

What are the symptoms of bubonic plague in humans?

Swollen lymph nodes (buboes), headache, fever, delirium, and hemorrhage.

How is bubonic plague contagious?

It can be spread by droplet spray, particularly from infected lungs.

What are the characteristics of bed bugs (Cimex lectularius)?

Wingless, reddish-brown, 5-8 mm in length, and lay eggs in furniture or wall cracks.

How long can bed bugs survive without food?

They can survive for months without food.

What type of insect are mosquitoes classified as?

Micropredators.

What do female mosquitoes require for reproduction?

Blood, while both males and females feed on nectar.

What diseases are transmitted by mosquitoes?

Dengue fever, dengue hemorrhagic fever, and malaria.

What is myiasis?

Infection of vertebrates by fly larvae (maggots).

What is the role of deerflies as vectors?

They are vectors for Tularemia and Loa Loa.

What disease is transmitted by tsetse flies?

African Sleeping sickness caused by Trypanosoma brucei gambiense.

What do houseflies do that makes them vectors of disease?

They carry bacteria and protozoan cysts from feces.

What is the life cycle of the horse bot fly?

Adult bot flies lay eggs on horse hairs, which are ingested; larvae live in the stomach and feed on blood.

What damage do cattle grubs cause?

They cause damage to the stomach mucosa of cattle.

What is the primary method of transmission for Chagas disease by reduviid bugs?

Transmission occurs through the bug's feces, which contain metacyclic trypanosomes.

What are the characteristics of the kissing bug?

They are temporary ectoparasites that typically feed on small mammals and can transmit Chagas disease.

What is the preferred environment for mosquitoes to lay their eggs?

Polluted standing water, preferably more than 4 days old.

What is the morphology of bed bugs?

They have a broad first segment of the thorax called the pronotum and three pairs of thin legs modified for running.

What is the significance of the blackfly as a vector?

They are vectors of Onchocerciasis, also known as river blindness.

What are ticks classified as in terms of their feeding habits?

Ticks are obligate, blood-feeding ectoparasites of vertebrates, particularly mammals and birds.

How do ticks differ from mites in terms of size and lifespan?

Ticks are usually relatively large and can live longer than mites, surviving for up to several years.

What are the two main types of ticks and how do they differ?

Hard ticks have a chitinized body and a hard plate (scutum), while soft ticks have a non-chitinized, flexible body.

What are the two main habitat requirements for ticks?

A large enough concentration of host species for developmental instars to locate new hosts and sufficiently high humidity to maintain water balance.

How do ticks adapt to low humidity environments?

Ticks resist desiccation by spending shorter periods questing for hosts and may enter diapause at unfavorable times.

What are some effects of tick bites on domestic animals?

Tick bites can cause mechanical damage, irritation, inflammation, hypersensitivity, anemia, and reduced productivity.

What serious condition can result from tick salivary secretions?

Some tick species' salivary secretions may cause toxicosis and paralysis.

What are the characteristics of soft ticks in the family Argasidae?

Soft ticks have a subterminal capitulum, no scutum, and a thick, leathery, often irregular idiosoma.

What is the life cycle of most tick species characterized by?

A large proportion of their life cycle occurs off the host, making their habitat particularly important.

What are common symptoms of tick-borne diseases?

Initial symptoms include flu-like symptoms such as fever, headache, nausea, and muscle stiffness, with more serious symptoms like rash and paralysis possible.

What disease is caused by the spirochete Borrelia burgdorferi and what is its tick vector?

Lyme disease is caused by Borrelia burgdorferi, with Ixodes scapularis as its tick vector.

What is the ecological role of most mite species?

The majority of mites are free-living predators, herbivores, or detritivores, occupying various habitats.

What are Demodex folliculorum and Demodex brevis known as?

They are known as eyelash mites.

What is acariasis?

Acariasis is the infestation by mites, which can result in severe dermatitis known as mange.

How do ectoparasitic mites feed on their hosts?

They inhabit the skin and feed on blood, lymph, skin debris, or sebaceous secretions by puncturing the skin or scavenging from the surface.

What is the primary mode of transmission for ectoparasitic mites?

Transmission from host to host is primarily by physical contact.

What is scabies and how is it transmitted?

Scabies is caused by a burrowing mite (Sarcoptes scabei) and is transmitted by direct physical contact.

What treatment is effective against mite infestations?

Acaricide drugs are effective in treating mite infestations.

What are the effects of mite infestations on host animals?

Mite infestations can cause significant welfare problems and economic losses.

What is the significance of the tick habitat in relation to their life cycle?

The habitat is crucial as a large proportion of the life cycle of most tick species occurs off the host.

What are the two main types of ticks based on their body structure?

Hard ticks and soft ticks.

What is the role of humidity in the habitat requirements of ticks?

Ticks require sufficiently high humidity to maintain their water balance.

What are the consequences of tick bites on livestock?

Tick bites can lead to mechanical damage, irritation, inflammation, anemia, and reduced productivity.