reproduction and development

ex: plasmodium ssp. and T brucei ssp

development only

ex: filaroid worms

Subphylum uniramia

                          class insecta (insects-hexapoda)

31 orders

 Subphylum Chelicerata

   Calss Arachnida

                      order acari (ticks, mites)

head: feeding and sensory (moutparts, eyes, antennae

Thorax: locomotion (3 pairs of legs, 2 pair of wings

Abdomon: digestion and reproduction

chitinous exoskeleton

annelid ancestor

open circulatory system, hemocoel, dorsal heart/pulsatile organs, tracheal system, salivary glands, tubular gut, gastric caecae, malphigan tubules, ventral nerve cord

egg, nymph, adult

no pupal stage

nymphs and adults occupy the same space and use the same food source

eg. cockroach

what defines complete metamorphasis

egg, larva, pupae

wings internal

pupa non-feeding

larvae and adults occupy different habitats and eat different foods

eg: mosquito

crushing-chewing

sponging

cutting-sponging

piercing-sucking (2 types)

eg cockroach

solid food

carnivore

omnivore

vegiterian

no blood

eg blow fly

 liquid food

no blood

salivate

defacate

aspirate

regurgitate

all falls under telemophagy:

eg horse fly

 laerate skin with mandibles and maxillae

pools blood on skin surface and sucked up with labella

pool feeder

name the characteristics of

piercing and sucking type 1

falls under solenophagy

eg mosquito

inserts stylus throughout the skin

probe for capillary

inserts stylus into capillary

tube feeder

name the characteristics of

piercing and sucking type 2

Falls under telmophagy:

 eg: teste fly

rigid labium

lacerates skin surface with labellar teeth

sucked up pooled blood

pool feeder

two winged flies only one pair being functional

2nd pair used as balancing organs for flight (haltares)

important vector group

complete metamorphasis (egg,larva,pupae, adult)

Name the biting Diptera!

mosquito

Name the biting Diptera!

black flies

Name the biting Diptera!

sand flies

Name the biting Diptera!

horse flies

Name the biting Diptera!

stable flies

Name the biting Diptera!

tsetse flies

only females suck blood

piercing-sucking type 1 mouthparts

 transmits protazo, filarial worms, viruses

males feed on nectar and plant juices

important genre: aedes, anopheles, culex

diverse natural histories

usually females avoid sites with wave action

Anopheles: swamps, etc

Aedes: artificial water containers, treeholes, flooding areas

 culex: semiperminant impoundments, polluted water

other: crabholes, underside of leaves in aquatic plants

filter feeders

a few species are predacious on other mosquito larvae

 submerge when alarmed

air tube for breathing

about 60 of the 2700 species attack human

rest feed on other random creatures

use vision, heat, and chemical cues such as CO2 lactic acid to find host

can be daytime or nightime feeders

vectors for malaria in humans

ex

gambiae complex: Africa

Albimanus: Central Amer, carribean

Darlingi: South America

Stephensi: India

maculatus complex: SE Asia

Punctulatus complex: New Guinea

located in zambia

use various means to protect population from malaria

hope to reduce it by 75% by 2011

120 mil cases worldwide

many mosquito species vector 

mosquito biting patterns match microfilariae present in peripheral blood stream

Culex, anopheles, crepuscular, nighttime biters

Aede, Mansonia, and Psorophora daytime biters

aprox 200 know

dozens of mosquito species as vectors

yellow fever

dengue/dengue hemorrhagic fever

most are zoonoses

st louis, western/eastern equine encephalitis viruses

west nile virus

hundreds to thousands of cases annually

maintained in sylvatic cycle

bridge vector to urban cycle

aedes aegypti principal urban vector

vaccine available

vector control can be effective

located mostly in SA (rain forest) and central africa

four serotypes of dengue virus

single infection can cause dengue

multiple infections cause hemorrhagic

2.5 billion people at risk

no vaccine

recent epidemics in cuba and brazil

Ae. Aegypti: SE US, Brasil, central and south africa

Ae. Albopictus: central america, central africa,  India,Indonesia,australia

discovered in uganda

epidemics europe and israel in 60-70s

NA in 1999

infects humans and a variety of animals (110 bird species)

primary vector is Culex spp and 25 other mosquito species

 blood donar transmission

incubation 3-14 days

no vaccine

3-15% fatal, 80% inapparently infected, 19% mild clinical disease, .67% encephalitis, death

can result in encephalitis, meningitis, fever

cutting-sponging mouthparts (only females)

transmit onchocerca volvulus

africa, central and south America

vector: simulium spp

eggs, larvae, pupae(in slowly running water)

avermectins successfully used as oral systemic treatment for humans

Piercing-sucking mouthparts (female only)

cause sanf fly fever (virus)

Bartonellosis spp (bacterium)

leishmaniasis spp (protozoa)

Phelbotomus spp (old world)

Lutzomyia spp (new world)

weak flyers and stay low to the ground biting the head, face, neck and sholder

Cutting sponging mouthparts (females only)

strong flyers, aggressive biters

Tabanus spp and Chrysops spp

mechanical transmission of anthrax, tularemia, surra, and anaplasmosis

 cyclodevelopmental transmisson of Loa Loa to humans by chrysops spp.

cause sleeping sickness

piercing-sucking 2 mouthparts (both sexes)

larviparous, "milk glands" (female)

pupation in soil

adults emerge in 3-4 weeks

24 glossina spp; tropical africa

weak flyers; aggressive biters

glossina palpalis, trypanosoma brucei gambiense (riverine)

Filth-inhabiting species

sponging mouthparts

musca domestica (muscidae)

blow flies (calliphoridae)

flesh flies (sarcophagidae)

mechanical transmission: typhoid fever, bacillary dysentery, trachoma, conjunctivitis, cholera, and yaws

Helicobacter pyloris- gastric ulcers

Escherichia coli

assassin bugs

new world only

simple metamorphosis

piercing-sucking mouthparts

insectivorous, hematophagous

crawl rather than fly

feed at night

peridomestic species dwell in cracks and crevices

 transmit Chagas' disease (T. Cruzi)

fleas

complete metamorphosis

wingless; walk/jump to host

piercing-sucking mouthparts

both sexes suck blood

host-specificity variable amoung spp

yersinia pestis: sylvatic plague (prairie dog is reservoir)

murine/endemic typhus (R. Typhi)

Tapeworm intermediate host

simple metamorphosis

wingless

movement by host-to-host transfer

Order Mallophaga- chewing lice

Trichodectes latus is intermediate host (dog tapeworm)

Order Anoplura (sucking lice)

pubic louse (phthiris pubis)

body/head louse (pediculus humanus spp)

can cause:

relapsing fever

epidemic typhus

trench fever

caused by Borrelia recurrentis

spirochete

lives in insect hemocoel

crush louse

infected hemolymph enter through break in skin or mucous membrane

Louse-Borne Typhus

Rickettsia prowazeki

multiply in insect midgut epithelium and shed in gut

pass out with feces and fecal remains can be infective for months

can be inhaled, skin breaks, or mucous membranes

Rochalimaea quintana

multiply in louse midgut epithelium and shed into gut

pass out with feces

can be inhaled, skin breaks, mucous membrane

rarely fatal

Subphylum Uniramia

 class insecta

 31 orders

ex insects-hexapoda

subphylum Chelicerata

Class Arachnida

Order Acari

ex ticks, mites

cephalothorax

abdomen

wingless

larva with 6 legs

nymph adult with 8 legs

body appears unsegmented

piercing-tearing

hypostome

chelicerae

pedipalps

salivary secretions form feeding tube in host skin (ticks and some mites)

hard ticks:

 Family Ixodidae (Dermacentor spp. Ixodes spp)

Soft Ticks:

Family Argasidae (ornithodorus spp.)

Mites:

Family Trombiculidae

(Leptotrombidium spp.)

mouthparts project forward

hard scutum dorsally

"ambushers" (await host) and will attach and feed for days

mate on the host

engorge, detach, drop

female lays eggs then dies

1,2, and 3 host species

Rickettsia rickettsia causes rockey mountain spotted fever in NA

D. andersoni vector in west and D. variabilis in central and eastern NA

 rickettsiae pass to host via tick saliva

transovarial transmission

RMSF is a zoonosis

can be fatal

transmit borrelia burgdorferi which causes lyme disease or lyme borrelios

I. scapularis : East NA

I pacificus:  West NA

I. ricinus: Europe

increase in disease in US related to deer population increase

not fatal

sequelae include neurological and cardiac malfunction and rheumatoid arthritis

treatable in early stages with antibiotics

vaccine is 70% effective

Mouthparts ventral

soft, leather-like integument

seek host (hunters)

attach and feed (20-30mins)

mate off the host

attach, engorge, depart

female produces dozens to hundreds eggs, then re-feeds

nighttime feeders

Borrelia and spirochaeta

tick borne relapsing fever

tropics and subtropics

zoonotic

small mammals reservoirs

1st feed to acquire infection

2nd feed to transmit infection

up to 11 febrile episodes in humans

scrub typhus

rickettsia tsutsugamushi

in asia, russia, and japan

small mammal reservoirs

mite larva are blood feeders

nymphs and adults trans stadially infected

transovarial transmission

zoonotic disease

List taxonomy for Order Kinetoplastida

 Subphylum Mastigophora

Order Kinetoplastida

           Family Trypanosomatidae

       Genus Trypanosoma

                   Subgenus-Schizotrypanum

             subegenus trypanzoon

  Genus Leishmani

Stercoraria-posterior gut development

discontinuous  development in mammalian host

vector is triatoma (reduviid bug) organism- typanosoma cruzi

salivaria-anterior gut development.

continuous development in mammalian host

vector: Tsetse fly (glossina)

organisms: T brucei brucei, T brucei gambiense, T. brucei rhodesiense

specialized mitochondrial structure containing tightly packed DNA in mini and maxi circles

Have a single mitochondrion

undulating membrane

microtubules (subpellicular)

glycosomes (carb metabolism) is minimally functional

forms differ in location relative to the nucleus and the single flagellum

trypomastigote, epimastigote, promastigote

Amastigote (intracellular form): flagellum not exteriorized

T. Cruzi is transmitted by blood sucking triatomine bugs (reduviid bugs, kissing bug, assassin bug)

Rhodnius prolixus, triatoma infestans

Species differ in feeding and defacating habits

Insects: Epimastigotes, metacyclic trypomastigotes (infective form)

Mammalian forms: Amastigot, trypomastigote

only in americas

16-18 mill infected

50,000 deaths yearly

transmission limited by vector

clearing of forests

zoonosis

blood transfusion

congeital transmission

research laborayory

Actue chagas disease:

mostly in children

inflammation of site of entry

chagoma-trypanosomal chancre (after 1 week)

romana sign in eye

lymph node and muscle infected

fevers, malaise, anoerxia, meningoencephalitis

heart: myocarditis-rhythm imblances, congestive failure

can self resolve: indeterminate phase

early immunosuppression

parasite controlled by cell mediated mechs such as CD8+ and CD4+ and T cells

question of autimmunity and cell damage resulting in chronic infection:

cell funeral hypothesis: infected cells undergo apoptosis, DC engulf apoptotic cells and recieve TLR signal

mature DC's present in parasite and host cell antigens to naive CD4+ and CD8+

The t cells reactive to host cause tissue destruction

no vaccine

no effective treatment

Blood smear during acute phase

biopsy of lymph node

detect anti-parasite IgG in chronic case

Xenodiagnosis: infect bug with blood of patient and examine bugs weeks later for detection (takes too long)

PCR

subgenus Trypanozoon:

Trypanosoma brucei brucei infects animals but not humans

Trypanosoma brucei rhodesiense: infect wild game and sometimes human

Trypanosoma Brucei Gambiense: infects humans

Transmitted by glossina spp aka tsetse fly (males and females go for blood meals)

only in africa

50 mil at risk

20,000 cases a year

 W Africa form: T.b.gambiense transmitted by glossina palpalis vecotrs being wooded areas best in dry season

E African form: Trhodesiense by glossina morsitans. vectors inhabit savannah

tourist very susceptible children rarely infected

Acute infection: trypanosomal chancre (inflammatory lesion), 1 week after infection

self resolves

stage 1 there is no CNS involvement

 systemic hemolymphatic illness: paraistes in lymphatis induce massive cell proliferation that become fibrotic (enlarged cervical lymph nodes)

heart symptoms in T.b.rhodesiense

spleen enlarges (monocytic proliferation)

polyclonal b cell activatio, high IgM titers

antigen-antibody complexes

immune mediated hemolysis

in blood

parasites are in the blood can evade immune response or die

as a result they peridocially change surgace coat proteins

antigenically different proteins expressed on coat VATS and VSG

CNS is involved and induce monocytic infiltration causing meningoencephalitis

lymphocytes and other mononuclear cells in CSF

increased CSF pressure

perivascular accumulation of parasites and monocytes

the infected become listless, indifferent, and daytime somnolence

E African form can be fatal

parasites in the blood and/or CSF

high IgM levels

treat with suramin, pentamidine,and organic arsenicals

Two morphological forms the promastigote and amastigote

Vectors are Genera Lutzomyia (NW) and Phlebotomus..sandfly

subclassification:

Viannia develop in hind guy then migrate to midgut and forgut

Leishmania are parasites that develop in midgut and foregut of vector

the forms differ in location of the kinetoplast relative to the nucleus and the single flagellum

trypomastigote

epimastigote

amastigote (intracellular form) flagellum not exteriorized

Metacylogenesis: transformation of promastigotes (trypomastigotes in gen trypanosoma) in vector gut to infective form

change to slender and elongated parasites

thickening of surface coat: Lipophosphoglycan is elongated

increase in glucose metabolism (glycosomes more active in amastigote stage)

use of amino acids as carbon source

Caustive agents: L donovani, L.infantum, L.chagasi

main reserviors are dogs, foxes in SA, rats, gerbils, other rodents in africa

mostly found in children and young adults

asymoptomatic (self resolving) 3-6 months incubation to fever, weight loss, anemia, hepatosplenomegaly, and leukopenia (drop in white cell count)

Kala-azar in india, Assam fever, dumdum fever, or infantile splenomegaly

Wasting Syndrome (cachexia) may be meditaed by excessive secretions of tumor necrosis factor and is an opportunistic infection (AIDS)

Viscerotopic disease caused by Ltropica: gulf war syndrome

post kala-azar dermal leishmaniasis: development of skin leasions several years after treatment.

Causative Agents: L. Mexicana complex and L. Braziliensis along with related spp.

L. Major, L. tropica, L. Aethiopica

Sporadic disease and epidemics animals are important reserviors

Viscerotropic leishmaniasis caused by L. Tropica (part of gulf war syndrome)

sore or lesion at site of promastigote inoculation

"oriental sore", Bagdad boil, Dehli boil

L. Tropica lesions tend to be crusted and dry

L. major lesions:lesions can self resolve

L. mexicana lesions on exposed areas of extremities, face, or ears

Diffuse cutaneous leishmaniasis caused by L. Amazonensis. Do not have a tendency to self resolve

Causative Agent: L. Braziliensis, L. panamensis

Secondary lesions of mucous membranes of nose, oral cavity, pharynx

RNA editing is the process of posttranscriptional sequence alteration via insertion or deletion of uridylate residues at specific sites of mitochondrial RNAs

Kinetoplastids DNA is organized in two forms: maxi circles and mini circles

Macxi circles encode the enzymes of oxidative respration

Mini circles encode sequences that determine specificity of editing; guide to RNAs

Key enzyme: 3' terminal uridylyl transferase (TUTase)

other types of RNA editing

Nucletotide insertion and/or deletion (seen in acanthamoeba spp; physarum spp paramyoxovirues i.e addition of G results in change of reading frame

Base modification: 

Cystidine to Uridine

Adenosine to Inosine (by ADAR)

cell mediated immunity

studies show resistance to re-infection is associated with TH1 cytokines (Intergeron gamma, IL12) and susceptibility is associtated with production of TH2 cytokines (IL4, IL5, IL10) by T cells

T regulatory cells CD4+ CD25+ foxp3- prevent total parasite clearance by play a role in maintaining immunity to parasite 

AIDS and Leishmaniasis are correlated

no vaccine

For cutaneous lesion ID of parasites in touch preparations

In visceral disease ID of parasite from aspirates obtained after splenic puncture

Detection of anti-leishmanial antibodies in serum (high in visceral leishmaniasis)

Leishmanin skin test (Montenegro)

DNA Analaysis; PCR

Prevention is difficult but due to significant animal reservoirs. Vector control most promising

Liposomal Amphotericin B for visceral leishmaniasis

pentavalent antimony and pentamidine for all Leishmanias

Milteofsine