Parasitology Exam 4

What type of arthropod is the mosquito?

Insect. Dipteran.

What is the distribution of the mosquito?

Worldwide.

What is the host/host spectrum of the mosquito?

Warm and cold-blooded animals. Depends on species.

What pathogenesis can mosquitoes cause?

Annoyance. Blood loss => anaemia. Allergic reactions in skin (mosquito bites). Production losses in livestock.

What type of metamorphosis do mosquitoes undergo?

Complex.

What are the stages of complex metamorphosis?

Egg, larva, pupa, adult.

What do female mosquitoes use blood for?

Use proteins to make eggs.

What is the difference between male and female mosquitoes?

Males have fuzzy antenna. Females do not.

Where are mosquito eggs laid, and where do immature stages develop?

In quiet, stagnant water.

What type of exoskeleton do arthropods have?

Chitinous external.

What type of appendages do arthropods have?

Jointed.

How is the arthropod body arranged?

Segmented into 2-3 body regions.

What type of circulatory system do arthropods have?

Open. Have haemolymph.

Are the nervous and excretory systems of arthropods advanced?

No.

Which arthropods have trachea?

Insects and arachnids.

How do arthropods respire?

By gills, booklungs, or trachea.

What type of digestive tract do arthropods have?

Complete.

Are arthropods monoecious or dioecious?

Dioecious.

What are the stages of simple metamorphosis?

Egg, nymph, adult.

In simple metamorphosis, do the nymph stages have wings? What size are they?

No wings. Smaller than adults.

In simple metamorphosis how mature are the nymph stages? Where are they in comparison to adults?

Sexually immature. In the same habitat.

What is the distribution of WNV?

Worldwide.

What are the primary hosts of WNV?

Birds.

What are the incidental hosts of WNV?

Humans. Horses.

What is the most common infection route for WNV?

Mosquito bite.

What are alternative routes of infection for WNV?

Congenitally/during delivery. Rarely, blood transfusion and organ donation.

What is the vector for WNV?

Mosquito.

Are most people with WNV symptomatic or asymptomatic?

Asymptomatic.

What are the mild symptoms of WNV?

Fever, headache, body aches, joint pain, vomiting, diarrhoea, rash, fatigue, weakness.

What are the severe symptoms of WNV?

Encephalitis, meningitis etc. Symptoms inc. neck stiffness, stupor, disorientation, coma etc.

What type of hosts are humans and horses for WNV? What does this mean?

Dead end. They cannot infect mosquitoes bc. the viraemia does not get high enough.

What is the leading cause of mosquito-borne disease in the continental US?

WNV.

Who is at greatest risk of severe WNV?

People > 60 yrs w/ underlying conditions, e.g. cancer, diabetes, hypertension, kidney disease etc.

What type of virus is WNV?

Flavivirus.

What is the common name for Calliphoridae?

Blow/bottle flies.

What is the common name for Sarcophagidae?

Flesh flies.

What type of myiasis do Calliphoridae and Sarcophagidae undergo?

Facultative.

What is facultative myiasis?

Larvae can be free-living or parasitic. Can adapt to parasitic existence in living host.

What is the host spectrum for Sarcophagidae and Calliphoridae?

For facultative myiasis, they lay eggs in living hosts w/ soiled/damaged tissues.

What is the pathogenesis caused by Sarcophagidae and Calliphoridae?

Anorexia. Weakness. Secondary bacterial infections. Fatalities due to toxin release. "Wool strike" in sheep and old, weakened dogs.

What are the physical body properties of the adult Sarcophagidae and Calliphoridae?

Gray or metallic bodies.

How do medical maggots treat open wounds?

Remove dead and infected tissue. Kill bacteria. Stimulate wound to heal.

How do you diagnose facultative myiasis?

By seeing larvae. Analyse posterior ends under microscope to differentiate types of larvae.

How do you treat/control facultative myiasis?

Cleanse wound and dress w/ insecticide. Use insecticidal sprays and dips. Careful husbandry. Medical maggots.

What are the common names for Cordylobia?

Tumbu/Mango fly.

What type of arthropod is Cordylobia?

Insect. Dipteran.

What are the hosts of cordylobia?

Humans, livestock, dogs, other mammals. Wide host spectrum.

What is the pathogenesis caused by Cordylobia?

Painful lumps/lesions.

Where are Cordylobia eggs laid?

In soil often contaminated w/ urine/faeces. On damp clothing. Larvae penetrate skin after transient host contact.

How are Cordylobia and Dermatobia hominis treated?

Carefully squeeze out of skin.

How are Cordylobia and Dermatobia hominis prevented?

Cover skin. Use insect repellent. Use window screens and mosquito nets.

In Africa, how are Cordylobia eggs killed?

Iron clothes that were put on the line.

What type of myiasis do Dermatobia, Cordylobia, and Cuterebra undergo?

Obligatory myiasis.

What is obligatory myiasis?

Dipteran larvae are dependent on animal host for certain portion of life cycle.

What is the common name for Dermatobia hominis?

Primary human bot fly.

Where is Dermatobia hominis found?

C and S America.

What are the hosts of Dermatobia hominis?

Humans, livestock, dogs, other mammals.

What is the pathogenesis of Dermatobia hominis?

Painful lumps/lesions.

How is the lifecycle of Dermatobia hominis unique?

It hijacks a different fly for egg delivery to the host.

Who is more likely to get myiasis?

Those w/ untreated/open wounds.

What type of arthropods are Cordylobia, Cuterebra, and Dermatobia hominis?

Insects. Dipteran.

What are the hosts of Cuterebra?

Mainly rabbits, mice, squirrels, and chipmunks. Cats and dogs are suitable.

What does Cuterebra cause?

Large, subcutaneous cyst, often in cervical region of cats/dogs. Also in nasal/oral regions. Brain migration is fatal.

How can Cuterebra be treated in companion animals?

Surgical removal.

How do Cuterebra larvae enter the host?

Through ANY natural body opening.

What are the common names for Pthirus pubis?

Human pubic louse, "crabs".

What type of louse are Pthirus pubis?

Sucking louse.

What type of arthropod are Pthirus pubis and Pediculus humanus capitis?

Insect. Anopluran.

What is the distribution of Pthirus pubis?

Worldwide.

What is the host of Pthirus pubis and Pediculus humanus capitis?

Humans.

How is Pthirus pubis spread?

Primarily via sexual contact (pubic hair bridge). Minor route: via fomites, e.g. bedding.

What pathogenesis does Pthirus pubis cause?

Itching, "pruritus", in pubic and groin area. Potential for secondary bacterial infection.

What do Pthirus pubis look like compared to most lice?

More rounded body. Large tarsal claws for grasping coarse pubic hair.

Are Pthirus pubis bloodfeeders?

Yes.

Can pets transmit Pthirus pubis?

No.

Can Pthirus pubis transmit pathogens/disease?

No.

How can Pthirus pubis be controlled?

Examine all sexual contacts. Treat all who are infested. Machine wash and dry clothing and bedding at hot temps. Dry-clean non-washable items or seal in plastic bag and store for 2 weeks. Do NOT use fumigant sprays or fogs: not necessary and can be toxic.

How long-lived are sucking live when removed from host?

Short-lived.

What are Anoplura eggs like?

Operculated.

What is the common name for Pediculus humanus capitis?

Human head louse.

What is the distribution of Pediculus humanus capitis?

Worldwide.

How is Pediculus humanus capitis transmitted?

Direct contact via hair bridge. Fomites.

What is the pathogenesis of Pediculus humanus capitis?

Asymptomatic w/ first or light infestation. Itching.Tickling feeling of something moving in hair. Irritability. Sleeplessness. Secondary bacterial infections from sores.

Where does Pediculus humanus capitis reside? Why?

Close to scalp to maintain body temp.

Are Pediculus humanus capitis bloodfeeders?

Yes.

How can Pediculus humanus capitis be prevented/controlled?

Avoid head-to-head contact. Do not share items. Disinfect combs/brushes. Machine wash and dry clothing. bedding etc. that was used during the 2 days before treatment at high temps. Dry-clean or store non-washable items in sealed plastic bag for 2 weeks. Vacuum floor and furniture esp. where infested person sat. No fumigant sprays or fogs: not necessary and can be toxic.

What type of arthropod are bed bugs?

Insect. Hemiptera.

What is the distribution of bed bugs?

Worldwide.

What are the hosts for bed bugs?

Mainly humans. Occasionally pets and wild animals.

What pathogenesis do bed bugs cause?

Red, itchy lesions. Anaemia. Sleep disruption.

Are bed bugs blood feeders?

Yes. At nighttime.

Do bed bugs transmit disease?

No.

How do you prevent bed bugs?

Caulk cracks. Avoid clutter. No discarded furniture. Suitcases off floor/on metal racks.

How do you control/eliminate bed bugs?

Licensed pest control that uses insecticides (expensive). Heat treatment or certain gases. Wash and dry bedding at high temps. Steam upholstery. Interceptor cups.

Describe the morphology of the hemiptera arthropods.

2 pairs of wings. May be vestigial. Triangular dorsal plate. Piercing/sucking mouthparts. Simple metamorphosis.

What type of arthropod is Ctenocephalides felis?

Insect. Siphonaptera.

What are the preferred hosts for Ctenocephalides felis?

Cats, dogs. Will take blood meal from humans if present, but not preferred.

What pathogenesis does Ctenocephalides felis cause?

Localised scratching/chewing/grooming. Hair loss. Erythema. Papules and crust. Blood loss. Flea bite dermatitis.

What is the common name for Ctenocephalides felis?

Cat flea.

What is the most common ectoparasite of dogs/cats in N America?

Ctenocephalides felis.