Caused by: Babesia bigemina

Transmitted by:  Boophilus annulatus (tick)

DALY

Diasability adjusted life years (of economic productivity)

Includes mortality (premature death) and short or long-term disability

Rigid exoskeleton (cuticle)

Phsyiological phenomena: molting (ecdysis)

Group of distinct organisms that share the molting trait

Other features:

Ventral nerve cord

Open circulatory system

Phylum: Arthropoda

Subphylum: Chelicerata

Mouthparts point straight out and cut like an electric steak knife

No antennae

Class: Arachnida

Order: Scorpiones

Four pairs of legs (may have 3 as larvae)

Fused cephalothorax (head and thorax)

Segmented abdomen

Pedipalps modified as claws (chelate)

Last abdominal segment (telson) modified as stinger

Class: Arachnida

Order: Araneae

Fused prosoma (cephalothorax) connected to opisthosoma (abdomen) by narrow pedicel

Pedipalps have sensory function

Chelicerae modified to function as venomous fangs

All spiders exert venom

Are all predators

Class: Arachnida

Order: Acari

(Ticks and mites)

Whole body fused

Podosome is part of body where legs are attached

Tick head is called capitulum.  Acts as a light sensing organ.  No brain or central nervous system here

Two pairs of antennae

Five or more pairs of legs

Biramous appendages

Fused cephalothorax, segmented abdomen with non-stinging telson

Parasites of snakes, sheep, etc

Live in nasal passages

No legs, feed on blood

Generally transmitted when an infected mother is nuzzling/grooming her offspring

Subphylum: Atelocerata

Class: Hexapoda

(Insecta)

1 pair of antennae

1 pair of compound eyes

3 body segments: head, thorax abdomen

3 pairs of legs

some have wings

Subphylum: Atelocerata

Class: Diplopoda 

(Millipedes)

Head and trunk

30+ pairs of legs

2 pairs of legs/body segment

Cylindrical body

Non-venomous mouthparts (feed on decaying matter)

Defense glands secrete cyanide located on each segment

Subphylum: Atelocerata

Class: Chilopoda

(Centipedes)

Head and trunk

15+ pairs of legs

1 pair of legs/body segment

Dorso-ventrally flat

Mandibles modified as venomous fangs

Subphylum: Atelocerata

Class: Hexapoda

Subclass: Entognatha

wingless; mouthparts recessed into pouch in head

Invaders and can cause infestation, but they don't vector/cause any diseases

ex: booklice, silverfish

Subphylum: Atelocerata

Class: Hexapoda

Subclass: Insecta

2 pairs of wings (may be secondarily modified to 1 pair or lost entirely), 

ectognathous: External mouthparts

Moving from the wild to inside a human dominated environment.

Live around domestic environment in the wild and will move into domestic houses (smoky brown roaches)

Some species are no longer found in the wild

Some bugs, like german roaches, are ONLY found around people

Coxa: Section of leg attached to body

Trochanter: Second segment of leg

Femur: Third segment of leg

Tibia: Fourth segment of leg

Tarsus: After tibia, often subdivided into several sections "foot"

Pleural membrane: Stretchy membrane allows to take up food because it can stretch to add more room in abdomen

Cercus: Sensory structure; receptors to gain info about environment

Ovipositor: Used for laying eggs

Spiracle: Opening to respiratory system

Tergum: Plate that covers the dorsal surface

Sternum: Shield or plate that covers the ventral surface

Sclerites: Rigid plates.  Exocuticle thick

Intersegmental membranes: flexible areas between sclerites.  Exocuticle thin

Epicuticle:  Outermost layer of exoskeleton, made up of waxes.  Waterproofs the insect (keeps water in and prevents desiccation

Exocuticle:  Makes up the rigid parts of the exoskeleton, extensive cross-linking

Endocuticle:  Some cross-linking, not really extensive- retains flexibility

Epidermis: Part that is alive

Seta: Mechano-receptor hair, sensitive to air movements, distributed all over the bodies of insects; why it's so hard to swat a mosquito

Circular muscles form digestive tract that contract in waves, like us

Logitudinal muscles used for movement - peristalsis

Crop: Storage organ

Malphigian: Excretory organs (extract waste= Frass)

Malphigian tubule: Fine hair like structures that extract waste from hemolymph and joins it to indigestible food to exit bug

Midgut: Where both digestion and nutrient absorption occur

Proventriculus: Break down and digest food

Peritrophic envelope: Area of cuticle ("chitin mesh") that wraps up food and keeps it from touching the surface of the gut

Rectum: Exit point, reserves water and mineral salts in body

Seminal vesicle: Where mature sperm is stored

Accessory gland: Where sperm is made

Spermatheca: Where females store sperm

Ganglia

Subesophageal ganglion: Fuses ganglia and goes to different mouthparts = regulates mouthparts (chewing and feeding)

Compound eyes - ommatidium

Rhabdom: Contains photoreceptors

Pigment cells: Accept and encode various wavelengths

Secondary pigment cells: Ensure photons don't cross from one ommatidium to adjacent ones.  These cells determine the color of insect eyes

Axon: Stimulates action potential

Substance produced at one site in the body and has an effect at a different site

Mating, migration, diapause, insulin, molting

Active hunters (mosquitoes)

Ambush (ticks)

Nest parasites (kissing bugs): These are arthropods that leave birth nest or rodents nest

Detect odors including Carbon dioxides, lactic acids, octanol, phenolics, fatty acids esters

Carbon dioxides at a distance, lactic acids and others they need to get closer

Heat

Water vapor

Shape/color Vision

Vasoconstriction (Platelet aggregation)

Coagulation (Clotting)

Arthropod must be associated with the vertebrate in nature, in a manner consistent with a role in disease transmission 

The parasite/pathogen must be found to be associated with the vector in nature

The arthropod must be able to acquire the pathogen by feeding on an infective vertebrate under controlled conditions

An infected arthropod must be able to infect a suitable vertebrate under controlled conditions 

The parasite increases in number in the vector, but does not change in developmental state

ex: arboviruses

Parasite increases in number and undergoes some developmental changes in the vector

ex. malaria, leishmaniasis, many others

The parasite undergoes developmental changes in the vector without increasing in number

ex. filarial worms

Transmission from mother to offspring

Transovarial: embryo is infected

Transovum: egg surface is infected, larva is infected at hatching

Haller's organ present

Feed on blood

Ixodidae and Argasidae and Nutellidae

Egg-larva-nymph-adult

Larvae 3 pairs of legs, nymphs and adults 4 pairs

Sex can be distinguished in ixodid ticks by presence/absence of a scutum

Western USA

Pathogen: Borrelia hermsi, Borrelia parkeri, Borrelia turicata

Vector: Ornithodoros hermsi, Ornithodoros parkeri, Ornithodoros turicata

Africa: Mainly Borrelia duttoni vectored by Ornithodoros moubata complex

25 cases/yr in US; many in Africa

Treatment: tetracycline type antibiotics eg doxycycline

High fever, chills, headaches, etc over 4-6 days

Flush phase: temp falls, etc, symptoms resolve

Symptoms return, each cycle 7-14 days

Antigenic variation

Borrelia expresses antigenic protein on surface.  Host starts to kill bacteria, a few Borrelia undergo genetic rearragnement, express a different surface antigen.  Immune system doesnt recognize new antigen at first, so symptoms return

Ascending flaccid paralysis

Caused by neurotoxin in tick saliva

USA: Mainly Dermacentor andersoni, Dermacentor variabilis

Bigger issue in Australia: "paralysis tick" Ixodes holocephalus

Causative agent: Borrelia burgdorferi

Responds well to tetracycline antibiotics eg doxycycline

Is a zoonosis:

Reservoir host: Microtine rodents, especially the white-footed mouse Perimyscus leucopus

Vector: Black-legged tick (Ixodes scapularis)

Synonym Ixodes dammini in the East, Midwest

Ixodes pacificus on West Coast

Humans are dead-end hosts

Deer are refactory to infection

1. Spring thaw, Ixodes scapularis nymphs and adults become active, as do rodents

Nymphs (many infected from previous summer when they fed as larvae) find and feed on rodents, infecting them with Borrelia burgdorferi

Adults lay eggs

2. Later in Summer, eggs hatch and larvae quest, feed on rodents.  Since many of these hosts were infected a month or two earlier when the nymphs fed, lots of larvae get infected

3. In Fall, nymphs molt to adults, feed on large hosts such as deer.

Larvae also molt to nymphs; many overwinter as nymphs without feeding, form population of nymphs that feed in Spring and perpetuate the cycle

Much less frequent than Northeast and upper Midwest

Vector: Ixodes pacificus

Reservoir: Microtine rodents

Transmission is often associated with forested habitats, higher (and cooler) elevations

Less frequent contact with human populations

Ixodes scapularis is abundant, but:

Less of an "inverted feeding cycle" because of less extreme seasonal temperature range

Ticks more active at night = less contact with humans

Lizards, skinks frequent hosts for larvae, nymphs but lizards are not reservoirs

Borrelia-killing factor in blood of some

Reduced transmission of Borrelia at elevated temperatures: 23 degrees 100% transmission

33 degrees 0% transmission

Southern tick associated rashlike illness

Vectored by lone star tick, Amblyomma americanum

New species, Borrelia lonestari, may be etiolytic agent

Pathogen: Rickettsia rickettsii

Vectors: Dermacentor andersoni (West)

Dermacentor variabilis (East)

Amplification through chipmunks, microtine rodents

Formerly in Rocky Mountain states, but now more prevalent in Appalachian states

Symptoms: Fever, headache, malaise, RASH

Vector: Amblyomma americanum

Reservoir: white-tailed deer

Pathogen: Ehrlichia chaffeensis

Incubation period: 7 days

Fever, etc

Vector: Ixodes scapularis

Reservoir: white-footed mouse

Pathogen of horses: Ehrlichia ewingi or Ehrlichia equi

Pathogen of dogs: Ehrlichia canis

Disease of cattle, sheep, wild ruminants

Pathogen: Anaplasma marginale, Anaplasma centrale, Anaplasma ovis

Vectors: About 20 species of ixodid ticks

Dermacentor variabilis, Dermacentor andersoni most important in USA

Infect erythrocytes

Protozoan parasite related to malaria

Infects erythrocytes

Vector: Ixodes scapularis

Reservoirs/tangential hosts: B. Bigemini (cattle)

B. microti (rodents, occasionally humans)

Dermacentor spp

Rocky Mountains area

Often biphasic: symptoms abate, then return after 2-3 days

rarely fatal

Europe and northern Asia

Ixodes ricinus, Ixodes persulcatus

Can be fatal or have long-term complications

Subphylum Arachnomorpha

Class Arachnida

Subphylum Arachnomorpha

Class Arachnida

Order Scorpiones

Subphylum Arachnomorpha

Class Arachnida

Order Araneae

Subphylum Arachnomorpha

Class Arachnida

Order Acari

 Subphylum Arachnomorpha

Class Arachnida

Order Acari

Family Argasidae

Soft ticks; flexible exoskeleton with hard spines and structues, mouth parts on underside between first pair of legs

Can mate off the host, and only one sexual pheremone is involved

Subphylum Arachnomorpha

Class Arachnida

Order Acari

Family Ixodidae

Hard ticks; thickened exoskeleton; mouth parts can be seen from top; festoons on bottom abdominal side.  Females have a scutellum (scutum)

Can mate on the host, numerous sexual pheremones

Subphylum Mandibulate

Superclass Crustacea

Subphylum Mandibulate

Subclass Pentastomatida

Infraphylum Atelocerata

Infraphylum Atelocerata

Class Diplopoda

Infraphylum Atelocerata

Class Chilopoda

Epiclass Hexapoda

Class Entognatha

Wingless, mouthparts recessed into pouch in head; springtails, proturans, diplurans (not medically important)

Epiclass Hexapoda

Class Insecta

Reservoir:

           Vector/arthropod cause: Sarcoptes scabei

           Pathogen:

           Transmission cycle:

           Mechanism:

 Symptom: Allergic response, intense itching, scratching results in secondary infections

Treatment: topical steroids for humans; ivermectin, Frontline for dogs

Reservoir: Chigger mites

           Vector/arthropod cause:

           Pathogen: Orientia tsutsumagushi

           Transmission cycle: vertical

           Mechanism:

 Symptom:

Treatment: tetracycline type antibiotics

Reservoir:

           Vector/arthropod cause: House mouse mite, Liponyssoides sanguineus

           Pathogen: Rickettsia akari

           Transmission cycle:

           Mechanism:

 Symptom: Fever, headache, malaise

Treatment: doxycycline

Reservoir:

           Vector/arthropod cause: Ornithodoroa hermsi

           Pathogen: Borrelia hermsi

           Transmission cycle:

           Mechanism:

 Symptom: High fever, headache, chills, muscle and pain, nausea, dizziness, vomiting. Then "flush" - decrease in temperature, decrease blood pressure, symptoms disappear, then return (7-14 day cycle)

Treatment: doxycycline

Reservoir: Rodents, white-footed mouse (Perimyscus leucopus)

           Vector/arthropod cause: Black-legged tick (deer tick) Ixodes scapularis (East and Midwest) Ixodes Pacificus in West Coast

           Pathogen: Borrelia burgdorferi

           Transmission cycle:

           Mechanism:

 Symptom: Rash (Erythema), muscle pain (myalgia), arthritis, carditis, memory problems

Treatment: doxycycline

Reservoir: chipmunks, microtine rodents (amplified)

           Vector/arthropod cause: Dermacentor andersoni

           Pathogen: Rickettsia rickettsii

           Transmission cycle: Vertical and horizontal

           Mechanism:

 Symptom: Fever, myalgia, headache, nausea, and petecial rash

Treatment: doxycycline and chloramphenicol

Reservoir: White-footed mouse

           Vector/arthropod cause: Ixodes scapularis

           Pathogen:

           Transmission cycle:

           Mechanism:

 Symptom:

Treatment:

Reservoir: B. bigemini, cattle, B. microti, mice

           Vector/arthropod cause: Ixodes scapularis

           Pathogen: Apicomplexa

           Transmission cycle:

           Mechanism: Infects erythrocytes

 Symptom:

Treatment:

Reservoir:

           Vector/arthropod cause: Demodex

           Pathogen:

           Transmission cycle:

           Mechanism:

 Symptom:

Treatment:

Reservoir:

           Vector/arthropod cause: Chicken mite Dermanyssus gallinae which parasitize chickens and other bird species

           Pathogen:

           Transmission cycle:

           Mechanism:

 Symptom:

Treatment: w/ antihistamines, steroids, eliminating contact w/ mites

Class Insecta

Order Blattodea

Incomplete metamorphosis (egg-nymph-adult)

Eggs in ootheca

Pronotum large, shield-like

Mandibulate mouthparts

Antennae very long

Long hairly legs- fast runners

Forewings thickened

Paired cerci on abdomen

Blatella germanica

All stages aggregate in dark enclosed spaces, prefer wood or paper surfaces

Need humid warm environment

Blatta orientalis

Preferred habitat humid, cooler

Often associated with drains and sewers

Not highly mobile

Periplaneta americana

Largest species infesting houses in North America

Prefer warm and humid areas, eg around pipes, water heaters, drains, sewers, crawl spaces, attics, voids in walls and between floors, etc

Supella longipalpa

Ootheca glued to inconspicuous places such as behind furniture, cabinets, picture frames, walls and ceilings

Need high temperature, but can survive lower humidity than German roaches

Periplanta fulginosa

Found in wood piles, leaf litter

Will invade houses

Limiting entry to house 

Crickets

Orthoptera Gryllidae

Camel (or Cave) Crickets

Orthoptera Gryllacrididae

Earwigs 

Order Dermaptera

Silverfish

Order Thysanura

Behavioral: A heritable change in behavior that reduces exposure to insecticide

Penetration: A heritable change in the cuticle that reduces the rate that insecticide penetrates into the insect

Metabolic: A heritable change in the rate at which chemicals are metabolized and excreted

Target-site: A heritable change in the specific site at which an insecticide binds 

Order Phthiraptera

Suborder Anoplura

Eyes reduced or absent, antennae segmented

Piercing, sucking mouthparts retracted into head

Legs are very well developed for grasping hair

Robust tarsal claws allow firm attachment to host

Pediculus humanus capitus 

Incomplete metamorphosis

Three nymphal stages

Eggs are attached to the scalp with "cement" form female's reproductive system

Pediculus humanus humanus 

Only attach to host to blood feed; return to clothing once done

Attach eggs to host clothing; only type of lice to lay eggs off of the host

More resistant to lower temps and humidity

The condition of being infested with lice

Dermatitis and secondary infection occur in severe cases

Plica polonica = fecal material and matted hair provide medium for fungal growth --> hair becomes cemented and scalp inflamed

Pthiris pubis

More robust, triangular/large claws for coarser hair

Transferred through sexual contact

Cause intesne itching/dermatitis

Can use OTC pyrethin lotion or shampoo

Causative agent: Rickettsia prowazekii (intracellular bacterium)

Vector: Pediculus humanus humanus

Reservoirs: Humans

Symptoms: High fever, muscle/joint pain, headaches, thoracic rash

Necrosis and gangrene

Some reservoir people are asymptomatic carriers (main disease carriers)

Bacteria transmitted in frass or in body fluids if lice is crushed

In human host, bacteria destroy epthelial lining of blood vessel

Treatment: Tetracycline antibiotics eg doxycycline

Flying Squirrels in Southeast can be reservoirs

Vector is Neohaematopinus sciuroptera

Most outbreaks in Ethiopia (1000-5000 cases/year)

Vector: Human Body Louse

Reservoir: Humans

Pathogen: Borrelia recurrentis (bacterium)

Borrelia released when lice are crushed, not in saliva or feces

Symptoms: Sudden fever, headache, anorexia, nausea, dizziness, coughing, vomiting, decrease in platelets, liver and spleen enlarge which can increase difficulty breathing

Treatment: Tetracycline, penicillin

Vector: Body louse

Reservoir: Humans

Pathogen: Bartonella quintana

Symptoms: Headache, myalgia, fever, nausea, NOT FATAL

First noticed in troops during WWI

Haematopinus suis

May transmit swinepox

True vessel feeders

What lice are

Two-wing flies (posterior are peg-like halteres used for balance)

complete metamorphosis

Varied mouthparts

Order Diptera

Suborder Brachycera

Small-large stout bodies

Antennae made of 3-6 short segments

Larval stage has reduced head

Most of the species are predators or scavengers

Order Diptera

Suborder Nematocera

Small, delicate, gnat like

long filamentous antennae composed of 6+ similar freely articulate segments

Larval stage has a well developed head

Four families:

Culicidae (mosquitoes)

Psychodidae (moth/sand flies)

Ceratopogonidae (biting midges)

Simuliidae (Black flies or buffalo flies)

Order Diptera

Suborder Nematocera

Family Simuliidae

Black flies or buffalo flies

stout bodies and humped backed

found all over world

1554 species; four medically important:

simulium, prosimulim, cnephia, and austrosimulium

strong wing, long distance fliers

largely diurnal, vision important

adult females blood feed

Morphologically identical adults, but genetically and biologically unique

Life cycle: Eggs are ovoid and triangular

Eggs are either laid onto a substrate at the surface of running water or directly onto the water's surface

Larvae/pupae are aquatic, live in running water

Elongated and tubular

Seven larval instars

Mouthparts have prominent cephalic fans

Silk secreted from salivary glands helps with movement in the stream

Prefer clean, flowing water

Pupal stage

Builds a cocoon, during molting, pupal gills are exposed thus providing continuous exposure to oxygen

Its non-feeding

Characteristics of pupa useful for IDing species

Emergence 6-9 am; at cooler temps, later in the day

Mating and Dispersal

Mating usually while flying

Males make small swarms 

No pheromones involved

Two-chambered spermatophore is transferred into female

Feeding

3 types of female feeders:

Obligate autogeny: No blood needed, never a vector

Primiparous autogeny: No blood needed for first batch, but need after that; more common amongst river species

Obligate anautogeny: Need blood every batch (best pathogen vectors); more common amongst small stream species where larval food less abundant/less quality

Occurs during daylight

Pool feeders; commonly bite in same area as previous bites

Medical/veterinary importance:

Simulitoxicosis: toxic reaction to saliva

Can kill livestock if numbers are excessive

Onchocerciasis (river blindness)

River blindness

Pathogen: Onchocerca volvulus

Symptoms: Nodules with adult female worms on the head in new world, on body in old world (elephant skin)

Microfilariae migrate through skin --> skin thickened/depigmented/leathery --> cracks = elephant skin

Progressive blindness in 10-20% of infected

Control Strategies:

Kill the Fly

Onchocerciasis control project (OCP)

70s-2002

Larval Control:

insecticides

biological control (bacillus thuringiensis strain israeliensis)

infected people (ivermectin)

Community level:

Treat everyone is affected area annually; elimination of reservoir population

Disease of poultry, can decimate whole flocks

Expensive systems to exclude flies from poultry operations

Characterized by vesicles (clear blister) on tongue and mouth of cattle

Not lethal but bad for economy

Mosquitoes

Piercing-sucking mouthparts

Proboscis about as long as the thorax

Wings and body with hair modified as scales

Aquatic larvae, generally free-swimming

Life Cycle

egg --> 4 larval instars --> pupa --> adult

Subfamilies

1. Anophelinae; Anopheles

2. Culicinae; Aedes, Ochlerotatus, Masonia, Coquillettidia, Culiseta, 30+

3. Toxorhynchitinae; toxorhynchites

Eggs shape = species specific

Larva

Both anophelinae and culicinae feed by beating water into mouth-brushes to generate water movement, filter feed 

Host Finding/Selction:

Longer range attractants: CO2, lactic acid, octenol

Closer range: visual cues, heat, humidity, odor

target specific locations

Breeding sites:

Are not large bodies of water or flowing water (larvae usually eaten by fish)

Irrigation and drainage ditches produce many kinds

Can determine age by:

Count follicular relic multiply by 3 days

Accumulation of eye color pigment

Control Approaches:

Target larvae-

Found only in certain areas

Issues: habitat hard to access; efforts may disrupt natural control

Chemical larvicides

Target adults-

Control applied after natural control complete

Issues: Widespread so no target control; pesticide around other animals

adult spraying

Bio/natural control (pathogen, birds, etc):

Source reduction (eliminate breeding site)

Family Culicidae

Subfamily Anophelinae

Larvae

Have no siphon, have tergal plates, have palmate hairs, and larvae float parallel to water surface

Adult

Females: Maxillary palps long as proboscis

Males: Antennae are brushy; long palps, terminal segment "club like"

Feed straight into host

Use system of rectal spines to concentrate blood cells

Family Culicidae

Subfamilies Culicinae

Larvae

Have a siphon, no tergal plates, no palmate hairs, and larvae hang down from surface 

Adult

Females: Short maxillary palps

Males: Plumose antennae; palps long, hairy at tip

Feed down into hosts

Trap serum proteins and excrete water through malphigian tubules

Asian tiger mosquito

Ae albopictus

Came from old tires from Japan shipped to Southeastern US in 1984

Arthropod-borne virus

Transmission:

1. Mosquito female picks up virus from reservoir while feeding

2. Virus enters gut

3. Virus penetrates gut wall into hemocoel

4. Virus migrate to salivary gland and multiplies

5. Saliva injected into new host at feeding --> host infected

Sylvatic cycle between primates and Haemagogus spp.; urban cycle between humans and Aedes aegypti

Symptoms: Sudden fever, myalgi nausea, vomiting, reduced urine, low WBC

Nose/mouth bleeding, vomiting blood, jaundice, kidney/GI lesions

St. Louis Encephalitis

1. The mosquito will digest the HIV virus before it can penetrate the gut wall so chances of biological transmission is very unlikely

2. The mosquito has very little blood on mouthparts after feeding so chances of mechanical transmission is very unlikely

3. A mosquito sucks blood up one canal and delivers saliva via another canal.  This shows that the flow is unidirectional and the mosquito will not inject blood from a previous meal into a second host

Warm forested areas (New World)

Cool, arid areas (Old World)

Flies: Promastigotes (transferred to the human)

People: Amastigotes (sucked up by the fly)

Biting midges, No-See-Um's, Punkies, ("sandflies")

Wings generally with color patterns; wings folded over body at rest; not as hairy as true sand flies; legs proportionally smaller than sand flies

Four genera of medical or veterinary importance:

Culicoides (most significant medically)

Leptoconops

Forcipomyia

Austroconops

Distributed worldwide, associated with water, generally standing, as in ponds, marshes, and tree holes

Life Cycle:

Eggs are laid on the surface of wet soil, mud, leaf litter, semi-rotting vegetation, on objects near to or partly under water, sometimes in tree holes

Eggs have small hairs that retain a film of air around the eggs in water to allow respiration

Larvae:

4 larval instars

Larva has a well developed head and 11 body segments

Found in freshwater or saltwater marshy areas, and in wet and semi-waterlogged soil

Serpentine larvae move by rapid flexions of the body

Adults:

Males emerge earlier than the females, make swarms of 10-1000 individuals

In most species females require a blood meal to produce eggs (anautogenous)

In a few species females may mature first batch of eggs without a blood meal, but for subsequent egg batches they need blood

Feeding: Hosts include mammals, birds, possibly reptiles

A few species even suck haemolymph from other insects

Most species bite in early morning and around sunset

Generally exophilic (stay outdoors, don't enter houses) and exophagic (bite outdoors)

Serious biting pests

Major diseases transmitted:

Viral: 

Oropouche

Blue tongue virus in cattle

African horse sickness

Parasitic:

Mansonella in humans, horses, and cattle

Pathogen: Bunyaviridae

Vector: Culicoides paraensis

Reservoirs: Poorly understood but may include monkeys, sloths, birds

Epidemics in South and Central America

Primarily in urban areas

Up to 44% of population seropositive

Symptoms: Abrupt onset of headache, fever, myalgia, dizziness, chills, photophobia (meningitis sometimes occurs)

Remission is spontaneous, sometimes brief relapse after 10 days

No fatalities, Immune for life

Pathogen: Filarial worm

Vectors: Culicoides species

Enter vector as microfilaria, migrate from gut to thoracic flight muscle, develop to L3 stage, move to mouthparts, transmitted to host at subsequent blood meal.  Development requires 8-10 days

Widely distributed across Africa: M. perstans, M. streptocera

South America: M. ozzardi

Infections usually without clinical symptoms, but occasionally serious

Treatment: Ivermectin or diethylcarbamazine

Pathogen: Virus (serocomplex with 25+ serotypes)

Vector: Culicoides varripennis

Hosts: Sheep, other livestock

Reservoirs: Livestock with sublinical disease?

Class A quarantine disease: economic impact due to disruption in movement of livestock

Symptoms:
Fever, swelling of mucous membranes, necrosis of epithelium of nose and mouth, lesions between toes, lameness, respiratory distress, internal hemorrhaging, spontaneous abortion

Sheep: 20-75% mortality

Can also be fatal in horse, cattle

Most animals have subclinical infects, not clear why some develop severe illness 

Pathogen: Reovirus

Vector: Culicoides most important

Hosts and reservoirs: Various equids (wild and domestic)

Widely distributed across Africa; rarer epidemics in Pakistan, India, Spain, and Portugal

1. Fever form: mildest, seen in African donkeys and zebras

2. Cardiac form: Fever; oedema of eyes, head neck, chest; colic; hemorrhages in corneas and tongue; mortality up to 50%

3. Pulmonary form: Depression and fever, followed by respiratory distress, coughing, frothy discharge; mortality often >90%

4. Mixed form: Both cardiac and pulmonary symptoms

Control methods:

Insecticide applications- hard to target either larvae or adults

Repellents- work poorly

Special "no-see-um" proof netting

Management practices- Mostly around livestock

Reduce larval habitat

Ear tags impregnated with insecticide

Preventing access to host animals

"elephantiasis"

Filariasis is a general term for infection with nematode parasites

1.2 billion at risk

120 million infected

40 million disabled

Parasites:

Wuchereria bancrofti

Brugia malayi

Brugia timori

Reservoirs:

Only humans (anthroponosis)

Vectors:

Large variety of mosquito species including Culex, Aedes, Anopheles, and others

Microscopic examination for microfilariae

New diagnostic: Antigen-detection test

Parasite: Dirofilaria immitis (nematode worm)

Reservoir host: dogs

Also cats, but not as common

Vectors: Numerous species of mosquitoes including Aedes, Anopheles, Culex, Psorophora, Mansonia

Symptoms: Cough, exercise intolerance, and abnormal lung sounds in moderate infections

Diagnosis: Presence of microfilaria in blood sample (centrifugation test)

Abnormal radiograph: enlargement of the right side of the heart, pulmonary arteries

Serology: Sensitive antigen tests available

Treatment/Prevention:

Adulticides: Melarsomine dihydrochloride (Immiticide)

Thiacetarsamide (Caparsolate)

Preventatives: Diethylcarbamazine (requires daily treatment)

Ivermectin (Heartgard)

Milbemycin (Interceptor) (also includes hookworm, roundworm, whipworm)

Moxidectin (ProHeart)

Selamectin (Revolution) (includes fleas)

Class Hexapoda

Order Hemiptera

"half-wing"

Incomplete metamorphosis

Piercing-sucking mouthparts- fused into a beak or rostrum

Palps absent

Antennae with four segments

Flattened dorsoventrally

Most species feed on plants or are predators on other insects

Two families of medical significance:

Class Hexapoda

Order Hemiptera

Family Cimicidae

Bed bugs

Not known to vector any parasites or pathogens

Secondarily wingless, wings reduced to hemilytral pads

Class Hexapoda

Order Hemiptera

Family Cimicidae

Cimex lectularius

Cosmopolitan

Pest of humans, bats, domestic birds

Class Hexapoda

Order Hemiptera

Family Cimicidae

Cimex hemipterus

Worldwide in tropics

Pest of humans

Class Hexapoda

Order Hemiptera

Family Reduviidae

Subfamily Triatominae

"cone-nosed" or "kissing bugs"

Head elongated, with well-developed compound eyes 

Beak or rostrum fits into groove on base of thorax

About 118 described species in 14 genera

Southwestern USA

Problem associated with hypersensitivity to bites, anaphylactic shock syndrome

In some areas up to 20% of human pop' has Ab against Triatoma saliva

Only a small fraction of these are hypersensitive

Agent: Trypanosoma cruzi (Protozoan parasite, Order Kinetoplastida)

Vector: Triatomine bugs (Rhodnius)

Focus: Poor dwellings

Distribution: The Americas

Acute phase:
Romana sign (swelling around the eye)

Chagoma (skin sore and inflamed area at bite)

Often flu-like symptoms

Nifurtimox and Benznidazole can be used at this stage, but they are expensive, and have severe side effects

Chronic phase:

Parasite disappears from system except for cardiac and sometimes smooth muscle, rarely nervous tissue

Progressive tissue damage

Cardiac symptoms, leading to death, in about 30% of infections

Requires decades to progress

Currently no approved drug treatment or vaccine 

Eventually destruction of heart muscle (due to immune efforts to remove amastigotes) and loss of muscle tone leads to thinning of heart muscle, especially at tips of the ventricles, and cardiomegaly

Control:

Southern Cone Initiative

Vector control

Improved housing

Genetic modification of vector population:

Takes advantage of the presence of a symbiont, Rhodococcus

Symbiont has been engineered to express a peptide that kills T. cruzi in the gut of the vector

Development of a vaccine:

Difficult because parasite is efficient at evading immune response, genetic variability of parasite in field

In the US:

T. cruzi has been isolated from racoons, opossums, dogs in several areas of the southern US

Also found in several endemic Triatoma species

Very few human cases of T. cruzi infection acquired here

1. Local Triatoma species don't defecate on host

2. Housing in the US doesn't support colonization by triatomines

Pathogen: Plasmodium falciparum, P. vivax, P. malariae, P. ovale

Only P. falciparum causes significant mortality

Plasmodium gallinaceum (infects chickens)

Rodent-specific malarias:

Plasmodium berghei

Plasmodium yoelii

Plasmodium chabaudi

P. knowlesi is a parasite of long-tailed macaques

Vector: Anopheles (mainly A. gambiae species complex in Africa, A. stephensi in SE Asia, but many other species have a role

Symptoms: Extreme fever alternating with extreme chills, brief period without either, then cycle repeats

P. falciparum produces VAR proteins which allow the infected erythrocytes to stick to the endothelial cells lining capillaries.  Infect erythrocytes accumulating in capillaries can block blood flow, starving downstream tissues of blood.  Capillaries are especially abundant in brain tissue, so this effect can lead to cerebral malaria, a major cause of death, especially in children

Children under the age of five and women in their first, and to some extent second, pregnancies are the most at risk

Diagnosis:

Giemsa-stained blood smear (traditional method)

Immunofluorescence assay (IFA)

Observe with fluorescence microscope

Control:

Vector control (elimination of breeding sites)

Surveillance

Treatment of active cases (eg chloroquine)

More surveillance

Best current tool: Insecticide-treated bednets

Treated with permethrin

Sterile Insect Technique (SIT)

Family Psychodidae

Subfamily Phlebotominae 

Sand flies

Small, long-legged flies with narrow bodies

Wings and body conspicuously hairy

Lutzomyia, Sergentomyia, Phlebotomus are the predominant medically important genera

Inhabitants of the warmer areas of the world

Important in disease transmission

(Leishmania, Bartonella)

Complete metamorphosis

Only females blood feed

Weak fliers, tend to approach hosts by hopping along ground

Males have elaborate genitalia

Bites are painful, often intensely itchy, can last for days

Vectors of Leishmaniasis

Cutaneous leishmaniasis:

Open wet ulcerating sores on skin

Visceral leishmaniasis:

Spleen becomes grossly enlarged

Wasting of limbs, muscle mass, high fatality rate

Mucocutaneous leishmaniasis: (Espundia)

Parasite attacks and destroys mucosal tissue

Nose, lips, palate usually involved

Sometimes ear

Mortality unusual

In New World only

Treatment:

Pentavalent antimonials (Pentostam)(High degree of resistance)

Miltefosine: Effective at curing visceral (not cutaneous) 

Paromycin: Still in clinical trials for visceral 

Oroya fever

Pathogen: Bartonella bacilliformis (bacteria)

Vector: Lutzomyia verrucarum

Location: Andes, mostly Peru

Symptoms:

Severe hemolytic anemia, high fever, chills, headache

Verruga peruana: Complication with blood-filled blisters throughout skin

Usually not fatal, but can produce immuno-suppression that can lead to fatal secondary infections

Large family of sandfly-vectored viruses

Fever, headache, myalgia, photophobia

Self-limiting, generally lasts 2-4 days

Ctenocephalides felis felis

Flea Allergy Dermatitis - Severe Allergic Reaction to Flea salivary secretions

Dipylidium caninum

Hosts: Dogs, cats and children

Vectors: Dog flea (ctenocephalides canis, rarely found in North America mainly in Europe on dogs); cat flea; human flea

Life cycle of Dipylidium caninum:

Egg hatch and cysticercoids develops in flea or louse

Infected intermediate host with cysticercoids eaten by dog or cat

Cysticercoid develops into adult tapeworm in host's small intestine

Eggs passed in the feces of an infected dog or cat.  Eggs stick to perianal skin

Eggs ingested by a flea or louse

Digested and enters bloodstream

Kills adult fleas for a month

An insect growth regulator (IGR)

Does not kill fleas, sterilizes females

Methoprene

Pyriproxyfen

Bubonic Plague

Murine Typhus

Myxomatosis: Viral disease of rabbits

Dipetalonema reconditum: Filarial worm of dogs and foxes

Tapeworms: 

Dog tapeworm: Dipylidium caninum

Rodent Tapeworm: Hymenolepsis diminuta

Pulex irritans

Both genal and pronotal ctenidia are absent

Ocular bristle inserted beneath the eye

Tunga penetrans

Tropical and subtropical Africa and South America

Both genal and pronotal ctenidia absent

Female embeds head into host causing swelling

Echidnophaga gallinacean

Most abundant in southern states, but found worldwide

Female remains fastened to a single host

Xenopsylla cheopsis

Cosmopolitan

Both pronotal and genal ctenidia absent

Ocular bristle inserted in front of eye

Primary vector in Urban Cycle of Bubonic Plague

Rickettsia typhi

Vectors:

Northern Rat Flea and Oriental Rat Flea

Class Insecta

Order Diptera

Class Insecta

Order Diptera

Suborder Brachycera

Horse flies, deer flies, house fly, face fly, stable fly, tsetse fly, eye gnat, bot flies, louse flies, blow flies, flesh flies

Mostly stout-bodies flies

Large compound eyes

Antenna: First two segments greatly expanded, remainder reduced to filament-like structure called arista

Class Insecta

Order Diptera

Suborder Nematocera

Piercing-Sucking:

Mosquitoes, stable fly, horn fly, tsetse fly, louse flies

Sponging:

House fly, face fly, flesh flies, blow flies

Non-functional (atrophied, vestigial):

Warble flies and bot flies

Exclusion

Source reduction

Sanitation

Biological Control:

Parasitoid- An organism that spends its immature stages in or on another organism, the host, which it eventually kills. Adult parasitoids are free-living

Black dump fly:

Hydrotaea aenescens

Predator of the house fly

Fly pathogen:

Entomophthora- a fungus that attacks adult flies

Dung-beetles:

Family Scarabeidae

Disrupt manure to maximize rapid drying

Sarcophagidae

Larviparous: Eggs hatch internally so that larvae are "laid" by female

Calliphoridae

Adults have metallic appearance

Diptera species having larvae which normally develop in or on the body of living vertebrates

Predilection sites: Location where the parasitic larvae are found

Digestive tract: Gasterophilinae

Nasopharyngeal cavities and other internal respiratory systems: Oestrinae

Dermic or subdermic: Hypodermatinae and Cuterebrinae

Wound: Cochliomyia hominivorax

These are all subfamilies

Common horse bot fly:

Gasterophilus intestinalis

Oviposits on the horse's front legs

Throat bot fly:

Gasterophilus nasalis

Sheep nose bot:

Oestrus ovis

Nasopharyngeal bots of cervids:

Cephenemyia spp.

Common cattle grub:

Hypoderma lineatum

Northern cattle grub:

Hypoderma bovis

Cochliomyia hominivorax

Chemical control:

Avermectins such as ivermectin, doramectin, and abamectin

Stomoxys calcitrans

Both sexes blood feed

Checkerboard markings on abdomen

Developmental vector of Habronema microstoma, spirurid nematode causing summer sores in horses

Hippoboscidae

Don't transmit disease agents, don't cause illness

Nycteribiidae

Highly host specific

Both sexes feed on blood

Lack eyes and wings

Streblidae

Glossina spp.

Transmit the trypanosomes that cause African sleeping sickness

Glossina morsitans: Larvipositor

Nagana (cattle):

Trypanosoma brucei brucei

African Sleeping Sickness (Human):

Trypanosoma brucei gambiense

Trypanosoma brucei rhodesiense

All spiders have venom; no vegan spiders; not hematophagous

Silk, 8 legs, 2 body segments

Pedipalps, cephalothorax, and abdomen

Not a spider

No venom glands, do not secrete silk, single body segment

Kukulcania hibernalis

Most common spider found in Georgia homes

Most commonly misidentified as a brown recluse spider

American House Spider

Parasteatoda tepidariorum

Second most common spider found in Georgia homes

Pholcus phalangioides

Third most common spider found in Georgia homes

"Bounce" in web when disturbed

Heaviest spider found in Georgia

Subterranean so seldom seen

Latrodectus mactans

Red Hourglass

Smooth egg sac

Latrodectus geometricus

Orange Hourglass

Spiked egg sacs

Loxosceles reclusa

Not in web

Fiddle on Cephalothorax

No abdominal markings

6 Eyes, 3 dyads, arranged in horseshoe shape

Not a recluse because:

Found outdoors

Builds a web

Has 8 eyes

Mistaken for recluse because of the six eyes in three pairs

But has patterned abdomen

Only insects with stingers derived from ovipositor

True defensive/offensive venom

Africanized Bees (aka "Killer Bees")

Bombus

Solitary bees

Fuzzy abdomen

Not aggresive but capable of stinging if handled

Xylocopa virginica

Solitary bees (no hive)

Not aggressive but females capable of stinging if handled

Shiny abdomen

Vespa crabo

Can sting repeatedly (don't leave stinger like honeybees)

Trypoxylon

Solitary

Stings only if provoked

Mutillidae

Females wingless

Only females can sting; sting very painful ("cow killer")

Feed on nectar

Females enter nests of solitary bees, lay one egg that parasitizes bee larva

Two native species:

Tropical fire ant

Southern fire ant

Two imported species:
Red Imported fire ant

  Much more aggressive

Black Imported fire ant 

Very limited range

Winged males and females mate in midair

Fall back to the ground, males die shortly after

Mated queen's wings detach; she digs a hole in ground (nest)

She begins to lay eggs, which will develop into small workers in about a month or two

More than one queen in a colony

More difficult to control

Spread by budding

Mature colony may contain around 400,000 individuals

Phorid fly

Parasitic Ant:

Solenopsis dagerrei

Pogonomyrmex

Intensely painful sting but rare as ants are large and red and generally avoided 

Western Harvester Ant:

Pogonomyrmex occidentalis

Monomorium pharaonis

Main problem is contamination in hopitals, nursing homes, clinics, etc.

Hickory Horned Devil

Tomato Hornworm