Neurotransmission

Synapses:
-Chemical synapses:
--About 20nm, wider than electrical synapse.
-Electrical synapses:
--2~3nm, forming gap junctions.
--When gap juntions exist problem, it might cause hereditary disease.

Synapses & Neuromuscular junctions:
-Synapse is used for integration for messages.
--Doesn't always have action when recieving stimulation.
--*Proteins accumulate at postsynaptic side -> Postsynaptic density.
-Neuromuscular junction is between motor neuron & skeletal muscle fibers.
--One stimulation results into on action or movement.
--*Juntional fold -> increasing the surface area.
--*Synaptic vesicles fuses with the presynaptic membrane -> electric capacity (++)

Neurotranmitter -> Synthesis, Storage, Release, Action, Termination.

Neurotransmission:
-Ca2+ - dependenct release.
--Determination step -> vesicle getting close to membrane.
--Quantal Release:
---Ca2+ open the channel in great amount, kicking out Mg2+.
---Mg2+ stucks the channel, while lack Mg2+ -> Quantal Release.
-Activation of neurotransmitter receptor.
--Including NMDA Receptor & GABA Receptor.
-Termination of neurotransmitter activation.
--Ach: G-protein couple receptor.
--Dopamine(DA):
---Dopamine increases -> raises emotion -> split personality.
---Medicine blockage of dopamine return to pre-synapse decreases melancholy.

Presynaptic & Postsynaptic inhibition.

Ionotropic receptors(ligand-gated ion channels)
Metabotropic receptors(G-protein coupled receptors)

Neurotransmitters:
-Acetylcholine:
--Nicotinic receptors & M1, M2, M3, M4, M5 receptors.
-Catcholamines:
--Dopamine -> D1, D2, D3, D4, D5 receptors.
--Norepinephrine -> alpha(1,2) & Beta(1,2,3) receptors.
--Epinephrine.
-Amino Acids:
--Excitatory Amino Acids(EAAs)
---Glutamate(Aspartate) -> NMDA, AMPA & kinate receptors, metabotropic receptors.
--Inhibitory Amino Acids(IAAs)
---GABA -> GABA(A) & GABA(B) receptors.

Satellite Cells - PNS Neuroglia

Also called "Ganglionic gliocytes"
-Appears only with peripheral ganlia.

Schwann Cells - PNS Neuroglia

Sometimes called "neurolemmocytes":
-Forming myelin sheath around nerve fibers.

One Schwann cell ensheathes ..
-One myelinated axon or several unmyelinated axons.

Both myelin sheath and nodes of Ranvier are covered by a basal lamina.

Nodes of Ranvier:
-Interruptions in myelin sheath, exposing the axon.
-Result in saltatory conduction.

Microglia - CNS Neuroglia

-Smallest.
-With scant cytoplasm.
-Oval to triangular nucleus.
-Irregular short process.

Possibly derived from mononuclear phagocytes.

Function as phagocytes in CNS:
-cleaning debris and damaged structures (like phagocytes in PNS).

Ependymal Cells - CNS Neuroglia

Cell type -> low columnar to cuboidal epithelial.

Lining ventricles of brain & central canal of spinal cords.

Most are ciliated -> facilitating movements of cerebrospinal fluid(CSF).

Choroidal ependyma & choroid plexus epithelium:
-Special ependymal cells on surface of choroid plexus.
-Producing the cerebrospinal fluid(CSF).

Tanycytes:
-Found in floor of the 3rd ventricle.
-Involved in endocrine control of enterior pituitary.

Oligodendrocytes - CNS Neuroglia

Present in both gray & white matter of CNS.

Smaller & contain lesser processes with sparse branches.

Nuclei smaller, rounder & denser.

Cytoplasm is denser and contain large quantities of..
-Free ribosomes, rER, mitochondra & microtubules.

Classification:
-Interfascicular Oligodendrocytes:
--Found in rows among myelinated axons.
-Satellite Oligodendrocytes:
--Surround cell body of some large neurons.

Astrocytes - CNS Neuroglia

Largest & most numerous & most elaborate of all glial elements

Distinct cytoplasmic bundles(intermediate filaments):
-Glial Fibrillar Acidic Protein (GFAP)

Form pervascular end feet by processes:
-Blood-Brain Barrier(BBB).
-External & internal limiting membranes lining ventricular system.

Scavenging ions and remnants of neuronal metabolism.

Contribute to energy metabolism by releasing glucose from stored glycogen.

Corpora amylacea:
-Clusters of glycoproteins and lipoproteins contained in processes.

Recruit cellular scar tissue to damaged areas.

Abnormal increase of astrocytes near trauma -> gliosis.

-Fibrous astrocyte:
--Mostly in white matter of CNS, with long unbranched proccesses.
-Protoplasmic astrocytes:
--In gray matter of CNS.
--Stellate-shaped cell body with large nucleus.
--Many short banching process.
--Some surrounds synapses and nodes of Ranvier.

Cells of the Nervous System

Neurons:
-Cytology:
--Cell body(=perikaryon) + Neurites(axon + dendrites).
-Classification:
--Golgi type I & Golgi type II
-Myelin sheath on nerve fiber.
-Forming synapses between neurons.
-Small neurons reaches proximal parts where large neurons reaches distal part.

Neuroglia:
-CNS:
--Astrocytes, oligodendrocytes, ependymal cells & microglia.
-PNS:
--Schwann cells + satellite cells

Neuron cytology:
-Cell surface:
--Plasma membrane embedded with proteins -> channels, pumps & receptor.
-Cytoplasm:
--rER, Nissl body(large neurons), mitochondria, golgi apparatus.
--Filamentous organelles: microfilaments, microtubules & neurofilaments.
--lysosomes, lipofuscin, neuromelanin.( remnant of neurotrasmitter )
-Nucleus with prominent nucleolus.

Neurites:
-Axon:
--Surface -> axolemma
--Cytoplasm -> axoplasm
--Collateral branch -> 90 degree branch in middle.
--Terminal branch (Telodendria) -> ends as synaptic turminals. (100 degree)
-Dendrites:
--Dendritic spines -> increasing surface area.

Neurons:
-Cell bodies:
--CNS -> Nuclei
--PNS -> Ganglia
--*Nuclei & ganglia -> Gathering of neurons with same function.
--Spinal cord -> Laminae
--*Board like partition in the spinal cord.
-Axons:
--CNS -> Tract
--CNS -> Fasciculi
--*Pathway -> named by function, Tract -> named by destination.
--*Fasciculi has more than to functional component, can't name by destination.
--PNS -> Nerves

Classification of Neurons:
-Golgi type I (Principal) neurons:
--Projection neurons -> with distal destination.
-Golgi type II neurons:
--Interneurons -> with proximal destination.

Neurohistological techniques:
-Cation stain(Nissl stain), reduce silver methods, myelin stain(Weigert's stain).
-Golgi stain, filling techniques, histochemical stain.
-Electron & confocal microscopy.

Neuroanatomical Research Methods:
-Metabolic marking:
--Radioactively labeled 2-deoxy-D-glucose
--Neurons can only use glucose as the source of energy.
-Axonal transport:
--Anterograde -> from nuclei to fibers.
--Retrograde -> from fibers to nuclei.
-Transynaptic transport -> passes from on neuron to another.

Myelin sheath:
-CNS -> oligodendrocyte ( one to many ) - unmyelinated fibers
-PNS -> Schwann cells ( one to one ) - myelinated fibers
-Node of Ranvier -> saltatory conduction.

Nerve fiber -> axon & myelin surrounding it.

Size & Conduction Velocity of Nerve Fibers:
-Radius increase -> myelin sheath increase -> conduction velocity increase.
-In order of radius ( large -> small ):
--IA:motor to skeletal muscle + sensory from muscle spindle proprioceptive endings.
--IB:Sensory from tendons(tension), Ruffini endings in skin.
--II:Sensory from Meissner's(touch) & pacinian(press) corpuscles & similar endings.
--III:Sensory from small hair follicles and free nerve endings for temp & pain.

Synapes:
-Chemical synapes:
--Neurotransmitters released from synaptic vesicles(presynaptic terminals)
--Diffuse across synaptic cleft, bind on postsynaptic receptor.
--Receptors:
---Ionotropic receptor -> fast transmission.
---Metabotropic receptors -> slow transmission.
-Electrical synapes:
--Common in invertebrates & lower vertebrates (Ex. gap junction)

Introduction to Nervous System

Organization of nervous system
-Neurons (nerve cells) & supporting cells (neuroglial or glia)

Activities of nervous system:
-Conduction -> one cell to another.
-Synaptic transmission -> communication between cells adjacent.

CNS - Central Nervous System:
-Brain + Spinal cord.
-Gray Matter + White Matter.

PNS - Peripheral Nervous System:
-Cranial nerves + Spinal nerves + Ganglia

Size of Human Brain:
-Birth->400g, Adult male->1360g, Adult female->1275g
-Obtain connections by learning at age of 3.

Development of Central Nervous System:
-Sulcus limitans:
--in lateral wall of neural tube throughout future spinal cord and brainstem
--Dividing alar plate(dorsal->sensory) & basal plate(ventral->motor)
-4th ventrical:
--neural tube spreads apart forming the 4th ventricle.
-Brain vesicles and flexure:
--Cephalic flexure(Mesencephalon) -> forming future midbrain.
--Pontine flexure
---between metencephalon(Ant) & myelencephalon(Post) on dorsal surface.
--Cervical flexure -> between rhombencephalon & spinal cord.
--Rhombencephalon -> metencephalon + myelencephalon.

Orientation & Section of CNS:
-Ventral & anterior has the same meaning in brainstem & spinal cord.
-Brain:
--coronal section = frontal section.
--transverse section = horizontal section.

Main regions of CNS:
-Telencephalon -> cerebral hemispheres
--Cerebral cortex, corpus stiatum & cerebral white matter.
-Diencephalon:
--epithalamus, thalamus, hypothalamus & subthalamus.
-Cerebellum
-Midbrain
-Pons
-Medulla oblongata
-Spinal cord

Taenia saginata - Order Cyclophyllidea

Also known as "beef tapeworm".

Morphology:
-Adult: 6~15m, 1000~2000 proglottids.
-Unarmed scolex:
--4 spherical suckers, no hooks.
-Gravid proglottids:
--More than 15 lateral uterine branches.
--Containing approximatly 100,000 eggs per proglottid.
-Larva is called Cysticercus bovis. (One head vesicle)

Diagnostic stage -> intact gravid proglottids may be found.

Life cycle:
-Final Host -> Human.
-Intermediate Host -> Cattle.
-Prepatent period -> 10~12 weeks.

Epidermiology:
-Cosmopolitan, Africa, South America.

Pathology and Symptomatology:
-Dizziness, abdominal pain, headache, nausea, diarrhea, loss of appetite.

Diagnosis:
-Stool examination of eggs and segment (mainly segment).

Treatment:
-Niclosamide or praziquantel.

Order Cyclophyllidea

Scolex:
-Globular with 4 suckers, (with or without rostellum or hooks)

Reproductive organs:
-1 or 2 set in each segment.
-Genital pore laterally.
-Blind-ending uterus (eggs shed with gravid segments).

Eggs:
-No operculum, thin capsule.

Life cycle:
-Most tapeworms of birds and mammals belong to this order.
-Only on intermediate host.

Spirometra mansonoides - Order Pseudophyllidea

Epidemiology:
-Far east & southeast asia.

Human ingests procercoid or plerocercoid
-Acting as an intermediate host or paratenic host.

Infection route:
-Swallowed infected copepods in drinking water.
-Consumed raw snakes or tadpoles for medical reason.
-Placed poultices of frog or snake flesh on open wounds or lesions.

Pathology and Symptomatology:
-Slow-growing, tender subcutaneous nodules.
-Painful inflammatory reaction in surrounding tissues.
-Ocular sparganosis.
--Periorbital edema, pruritis and pain in subconjunctival & peri-orbital tissues.

Diagnosis:
-Based on examination of gross specimen from human lesion.

Treatment:
-Surgical removal.
-Praziquantel.

Spirometra spp. - Order Pseudophyllidea

Eggs are more pointed, uterus forms spiral coils (2~7).
Cirrus and vagina have separate openings.

Life cycle:
-Final Host: dogs, cats and wild carnivores.
-1st Intermediate Host: cyclops.
-2nd Intermediate Host: frog, snake, bird, mammal.
*Drinking water makes human a 2nd Intermediate Host.
*Eating a frog make human a Paratenic Host.

Larva is called Sparganum:
-plerocercoid, wrinkled, whitish, ribbon-shaped.

Causes sparganosis.

Diphyllobothrium latum - Order Pseudophyllidea

Also known as "broad" or "fish" tapeworm.
25m, yellowish-gray with dark central markings (uterus with eggs).

Scolex:
-Finger-shaped 2-3mm long (2 sucking grooves).
Proglotted:
-Anterior broader than long.
-Rosette-shaped uterus winding forward from ootype to uterine tube.
Eggs:
-lightly brown, operculated.

Life cycle:
-Final Host: man, dog, pig, cat, fox, polar bear and other fish-eating animals.
-1st Intermediate Host: Copepodes.
-2nd Intermediate Host: Fish (fresh-water~half fresh-water).
-3 larval forms:
--Coracidium - Procercoid - Plerocercoid.
-Prepatent period: 3~6 weeks.
-Lives in the small intestine.

Epidermiology:
-Temperate and sub-arctic areas.

Pathology & Symptomatology:
-Severe anemia.
--Assimilating large quantities of vitamin B12 -> CNS disease.
-Severe depletion of vitamin results in pernicious anemia.

Diagnosis:
-Stool examination -> egg.
-Treatment:
--Niclosamide or Praziquantel (high efficiency but expensive)

Prevention:
-Proper disposal of human feaces.
-Fish -> thoroughly cooked or frozen at -10°C for 24~48 hours.

Order Pseudophyllidea

Size:
-May vary from a few mm to 30 meters in length.

Scolex:
-With narrow, deep grooves (weaker than suckers)

Neck:
-Inconspicuous.

Proglottid:
-Usually one set of hermaphroditic reproductive organs.
-Numberous testes, vitellaria are scattered.
-Ovary bilobed.
-Gravid uterus is usually sinuous tube.
-Uterine pore opening on ventral side.
-Eggs operculated.

Introduction to Cestodes

General considerations:
-also know as "Tapeworms"
-Intestinal parasites found in aquatic and terrestial vertebrates.
-Flattened, ribbon-like, segmented worms.
-No alimentary canal, respiratory system, circulatory system.
-Ontogenesis of cestoda proceeds in most species.

Medically important:
-Order Pseudophyllidae.
-Order Cyclophyllidae.

Morphology and physiology of adult:
-No body cavity -> organs supported by cellular parenchyma.
-Tegument:
--Surface covered with a complex cuticle which is biochemically active.
--Cuticle with microtriches increasing area.
--Cuticle -> Absorption & Excretion

Osmoregulatory system:
-Flame-cell system:
--Connected to excretory canals which run the length of body.
--Concerned with excretion and osmoregulation.

Muscular system:
-All parts of cestodes are capable of considerable movement.
-Movement completed by muscle cell dispersed within body parenchyma.

Body Structure:
-Scolex:
--Used for attachment and locomotion.
--Pseudophyllidea -> 2 sucking grooves
--Cyclophyllidea -> 4 suckers +(Rostellum) +(hooks)
-Neck:
--Highly active region from which the tapeworm segment grows.
-Strobila:
--Comprising of a chain of Segment(Proglottids).
--Grow from the neck and pushes back.

Mature proglottid is hermaphroditic:
-Containing both male and female reproductive organs.
**Immature proglottids: none to one set of genitalia.
**Mature proglottids: both set of genitalia are fully developoed.
**Gravid proglottids: Uterus contains large numbers of eggs.

Reproductive system (Hermaphroditic)
*Protandry(androgyny): Male organs mature first.
*Gynandry(protogyny): Ovary matures first.

Male reproductive system (Ventral):
-Contain one to a large number of testes.
-Into single vas deferens -> currus sac containing the cirrus (penis-like).

Female reproductive system (Dorsal):
-Single ovary and usually lobed.
-Oviduct leads to ootype (where egg shell formation takes place)
-Ootype leads to vagina, provided with a receptaculum seminis.
-Uterus arise from the ootype.
--Pseudophyllidea:
---Opens to exterior by uterine pore.
--Cyclophyllidea:
---Ends blindly and does not open to the exterior.
---Assumes various shapes as it becomes filled with eggs.
---not discharged until the egg-filled segment break up.
-Genital pore:
--Opens either in the midline(Pseudophylidea) or laterally(Cyclophyllidea)
--Vagina and cirrus sac have common opening to exterior at the genital pore.
-Vitelline gland:
--Pseudophyllidea:
---Dispersed around with shape of small flowers.
--Cyclophyllidea:
---Triangular shape behind the ovary.

Larvae type -> Solid & Vesicular

Eggs:
-Outer->Egg capsule & Inner->Embryophore.
-Hexacanth embryo -> Oncosphaera.
-Pseudophyllidea:
--Operculated, embryo not yet developed.
-Cyclophyllidea:
--Not operculated, with Oncosphaera inside.

Larvae:
-Solid:
--Coracidium, Procercoid, Plerocercoid.
-Visceral:
--Cysticercus, Strobilocercus, Coenurus, Hydatide.
-Pseudophyllidea:
--Coracidium, Procercoid, Plerocercoid.
-Cyclophyllidea:
--Cysticercus, Strobilocercus, Coenurus, Hydatide, Cysticercoid, Tetrathridium.

Capillaria hepatica - Blood & Tissue Nematodes

Morphology:
-Adult: Male->15~30mm Female->10cm

Adult worms live in the liver.

Life cycle:
-Final Host: Rodents, lagomorpha, human.
-Transport Host: Earthworms.

Epidemiology:
-An occasional parasite of humans.

Pathology & Symptomatology:
-Adult:
--Loss of liver cells -> loss of normal function
-Eggs:
--Replace large areas of parenchyma
--Carried to lungs or other organs by the bloodstream.
-Causing liver disorders, hepatitis with eosinophilia.

Diagnosis:
-Liver biopsy.
-Discovery of eggs in human feaces.

Treatment:
-Poorly known.
-Albendazole.

Anisakis spp. - Blood & Tissue Nematodes

Morphology:
-Adult: Male->3.5~7cm, Female->4.5~15cm

Life cycle:
-Final Host: Marine mammals (whale & dolphine)
-Intermediate Host: Crustaceans.
-Paratenic Host: Seafishes, squid.

Epidemiology:
-Japan, Holland, Scandinavia, pacific coast of South America.

Pathology & Symptomatology:
-Abdominal pain, nausea, vomitting, diarrhea, peritoneal irritation.
-Hematemesis.
-Granuloma:
--extensive eosinophilic infiltration.

Diagnosis:
-Gastroscopy
-X-ray
-Immunodiagnosis

Treatment:
-Surgery

Prevention:
-Freezing at -20°C for 5 days kills the larva.

Gnathostoma spinigerum - Blood & Tissue Nematodes

Morphology:
-Adult: Male->11-31mm, Female->25~52mm
-Body is stout and pink in life, 4 circles of stout spines.
-Anterior part:
--Covered with transverse rows of flat, toothed spines.
--Following the spine is a bare portion.
-Posterior part:
--Numerous tiny cuticular spines.

Epidemiology:
-India, Burma, Thialand, Malaysia, Sumatra, Philippines.
-China, Japan, New Guinea.

Life Cycle:
-Final Host: cat, dog, tiger, leopard.
-1st intermediate host:
--Cyclops (freshwater copepods)
-2nd intermediate host:
--Freshwater fishes, crustacea, amphibia, reptile, birds and mammals.
-Human -> Abnormal host or paratenic host.

Pathology & Symptomatology:
-Gnathostomiasis externa.
-Epigastric pain, fever, vomitting, anorexia.
-Circumscribed patches of edema.
-eosinophilic myeloencephalitis.

Diagnosis:
-High eosinophilia.
-Immunodiagnosis.

Treatment:
-Surgical removement.
-Thiabendazole for skin and eye lesion.

Prevention:
-Cooling by any means will kill the worms.
-Don't eat raw or previously unfrozen fish in endemic area.

Angiostrongylus cantonensis - Blood & Tissue Nematodes

Also know as "Parastrongylus cantonensis" or "rat lungworm"

Morphology:
-Adult: male->18mm, female->25mm, barber-pole
-L1:330µm

Life cycle:
-Final Host: rats
-Intermediate Host: slugs, aquatic & terrestrial snails
-Paratenic Host:
--Terrestrial planarians, freshwater shrimp, land crabs, coconut crabs.
--Salad (infected while being crawled).
-Human -> Abnormal Host.

Epidemiology:
-Southeast Asia, Pacific islands.
-Taiwan: southern & eastern.

Pathology & Symptomatology:
-Incubation period: 12~28days (Average 16.5 days)
-Eosinophilic meningitis + eosinophilic meningoencephalitis.
-High eosinophilia (Both peripheral blood & CSF)
-Headache, stiffness & pain in neck.
--Photophobia, blurring of vision, retroorbital pain.
--eye invasion.

Diagnosis:
-Base on clinical symptoms accompanied by high CSF & blood eosinophilia.
-L5->recovered from CSF
-Immunodiagnosis->ELISA

Treatment:
-Thiabendazole & mebendazole.
-Antipyretics.
-Lumber puncture.

Trichinella spiralis - Blood & Tissue Nematodes

Morphology:
-Adult: male->1.5mm, female->3~4mm, newborn larva->80~120µm
-Stichocytes
-Male: no spicule, 2 prominent conical papillae on side of cloacal opening.

Life cycle:
-Female -> viviparous.
-Prepatent period -> 1 week.

Epidemiology:
-Central and eastern Europe.
-Central, South & North America.
-Parts of Africa & Asia.

Pathology & Symptomatology
-Penetration of adult females into mucosa.
-Migration of juveniles:
--Localized edema, myocarditis.
-Penetration & encystment in muscle cells
--extreme eosinophilia

Diagnosis:
-Muscle biopsy
-Exnodiagnosis
-Immunodiagnosis:ELISA

Treatment:
-Corticosteroids+Prednisone
-Mebendazole
-Albendazole

Prevention:
-Inspection of pork & screening of pigs by specific serological test.
-Destruction of rats, which acts as source of infection to pigs.
-Cooking of all things fed to pigs.
-Processing of meat by freezing (larvae killed at -15°C for 24 hours).
-Education of public concering the need for proper cooking of pork.

Toxocara canis - Blood & Tissue Nematodes

Morphology:
-Adult: male->10~12cm, female->12-18cm
-Egg: 90 x 75 µm

Life cycle:
-Prepatent period: 4 weeks
-Final Host: dog
-Paratenic Host: Human

Epidemiology:
-Worldwide distribution
-Mainly infects children between 1 to 4 years old
-Pica (Geophagia, Coprophagia)
-Infective rate:
--Boys : Girls = 2 : 1

Pathology & Symptomatology:
-Most infections are subclinical.
-Hypereosiniphilia, hyperglobulinemia.
-Ocular larva migrans
-Cough, wheezing, pulmonary infiltration.
-Fever, pallor, convulsion, hepatomegaly.
-Eosinophilic granuloma.

Diagnosis:
-Liver biopsy (Danger, harmful).
-Serodiagnosis:
--ELISA, IHA, fluorescent antibody test.

Treatment:
A.
-Thiabendazole: 25mg/Kg BW, b.i.d.
-Diethylcarbamazine(DEC): 2mg/KG BW, t.i.d.
B.
-Corticosteroids
C.
-Broad-spectrum antibiotics

*Infects baby dog when pregnant or breasting the baby dog.

Prevention:
-Protect children against contact with dogs or cat.
-Especially kittens & puppies.
-Regular deworming with anthelminthic drugs.
-Wash hands after contact with animals.
-Puppies and nursing bitches should not be allowed indoors.
-Children's pica habit should be stopped.

Blood and Tissue Nematodes of Man

Larva migrans:
-Migran of larval nematodes in unsuitable host.
-Unable to complete their normal development.
-Distributed in the host tissue & eventually dies.
1.Visceral: larvae of nonhuman ascarids.
2.Cutaneous: cat or dog hookworms, dog filariform larva.
3.Subcutaneous & Visceral: spiruroid larva.

Visceral larva migrans (VLM):
-Extraintestinal migration of larval nematodes of lower animals.
-Invading tissues:
--Liver, lung, eye, brain, spinal cord, heart, kidney, lymphn node.
-Toxocara canis (primary causative agent)

Cutaneous larva migrans (CLM):
-Life cycle:
--Dog -> Final Host
--Human -> Foreign Host
-Epidemiology: Cosmopolitan.
-Clinical aspect:
--Linear inflammatory lesion of skin -> creeping eruption.
--Secondary bacterial infections.
-Treatment:
--Thiabendazole: 25mg/Kg BW, b.i.d for 5 days

Hookworms - Intestinal Nematodes

Distribution between 45°N and 30°S, infecting about 9 billion people.

Infection of human:
-Necator americanus, ancylostoma duodenale.
Infection of other species:
-Ancylostoma caninum & ancylostoma braziliense.
-Ancylostoma ceylanicum & ancylostoma malayanium.

Copulatory bursa:
-For reproduction, attaches to the females vagina.

Transmission:
-Penetration of skin by filariform larvae(L3, infective)
-Ingesting of infective larvae in A. duodenale.
-Transmammary transmission of larvae in A. duodenale.

Diagnostic stage -> Egg in feaces.
Infective stage -> Filariform larva(L3).

Migrates similar to Ascaris lumbricoides.

Clinical pathology:
-Ground itch:
--Skin reaction at site of larval penetration.
--Feeling stinging.
--Followed by irration, erythea, oedema & papulovesicular eruption.
-Creeping eruptions:
--A. braziliense and A.caninum wandering through the cutaneous layer.
--cutaneous larva migrans cause intense irritation and inflammation.
--Most larvae die in the skin.

Migration of F-form larvae(L3):
-During invasion of circulation:
--Usually no ill-effect.
-During migration through the lung:
--pneumonitis with cough, wheeze, feever, transient X-ray shadows.
--Not as severe as Ascaris.

Causes hookworm anemia(HWA):
-Losses of blood, iron and proteins.
-Occasionally associated with folate deficiency.

Worms move every 4-6 hours -> blood leaking while hooking on different places.

Laboratory diagnosis:
-Direct smear for eggs (Oval-shaped, thin shell).
-Egg culture for 1st stage larva(L1).

Strongyloides stercoralis - Intestinal Nematodes

Also know as "threadworm", very small about 1mm only.
World-wide distribution, especially tropical and subtropical countries.

Free-living life cycle:
-can be completed with out human's participation.
-all life cycle occur in the soil.

Free-living(Inderect development):
-doesn't need any host to complete the life cycle.
-can be completed outside of host body.

Parasitic Generation(Direct development):
-larvae developes in the host's body and comes out in feaces.

Visceral Larval Migration - Filariform larva (L3) -> adult

Eggs in mucosa -> Rhabditiform larva(L1) in feaces
-Autoinfection -> develop into L3 -> penetrate intestinal skin.
-Direct Development -> develop into L3 -> penetrate skin.
-Indirect development -> develop into L3 (Soil) -> penetrate skin.

Transmission:
-Infective filariform(L3) larvae penetrates skin.
-Transmammary transmission of larvae in breast milk.
-Autoinfection:
--Rhabbditiform larvae enters circulation system directly then develop.
--After developed into filariform, enter circulation(direct development).
--Penetrate from perianal skin into body by host's own feaces.

Clinical Features:
-Cutaneous:
--Itchy dermmatitis,pruritus and rash.
-Pulmonary:
--Allergic and respiratory symtoms.
--haemorrhages in the long alveoli, pneumonitis.
-Intestinal:
--Diarrhoea, ulcerative enteritis, anaemia, malabsorption.
--Steatorrhoea, electrolyte disturbance and eosinophilia.
-Disseminated hyperinfection infection:
--Infection can be found in almost all organs.

Laboratory diagnosis:
-Finding rhabditiform larvae in feaces.
-Finding R-form larvae in duodenal aspirates.

Examination of feaces for S. stercoralis.
-Direct saline preparation.
-Formol ether concentration technique.
-Stool culture (L3 easier to exam).

Ascaris lumbricoides - Intestinal Nematodes

Largest intestinal nematode - mouth with 3 lips

Causes Ascariasis, about one fourth of world population is infected.
World wide distribution - where human feaces are used as fertilizer.
Children more often and heavily infected.

Diagnostic stage -> Eggs in feaces (Fertilized & Unfertilized)
Infective stage -> Embryonated egg (L2)

Pathogenesis:
-Effects of visceral larval migration (VLM)
-Abdominal pain, nausea, diarrhoea and vomiting
-Impaired absorption & Malnutrition.

Larvae migration:

Larva hatches in intestine -> Portal circulation -> Lungs(L3)
-> Trachea -> Pharynx -> Adults in small intestine.

*Mechanical -> inflammatory, bacterial infection & hypersensitive reaction.
*In lung -> Loeffler's syndrome (Ecdysis occur in lung)

Heavy infection:
-Intestinal obstruction & perforation.
-Bile duct and pancreatic duct obstruction.
-Can be fatal.

Atopic Ascariasis:
-Bile duct, pancreatic duct, liver, peritoneal cavity, kidney.
-Appendix, pleural cavity, upper respiratory tract.
-Atopic ascariasis causes granuloma.

Laboratory Diagnosis:
-Finding eggs in feaces
--Fertilized egg & unfertilized egg & decorticated egg
-Identifying worms expelled through anus or mouth

A. lumbricoides eggs:
-Fertilized egg & unfertilized egg & decorticated egg.
-Embryonated egg -> contains larva (R-form, 1st or 2nd stage)
--infective

Prevention and control:
-Preventing soil becoming feacally pulluted:
--avoid using human feaces as fertilizer.
-Preventing eggs from ingestion:
--wash hands before eating.
--avoid eating uncooked vegetables, salad or fruits.

Treatment:
-Levamisole & Albendazole & Mebendazole

Capillaria philippinensis - Intestinal Nematodes

Small whipworm which is normally parasitic in fish-eating birds.

Distribution:
-Philippine (Northern Luzon & North eastern Mindanao)
-Thailand & Japan

Infective stage -> larvae
Intermediate host -> fish
Natural definitive host -> fish-eating bird

Transmission:
-Ingestion of egg in raw undercooked fishes.
-Eggs develop into infective larvae in intestine.
-Autoinfection by ingestion of egg.

Clinical Features:
-Adults and larvae live in crypts of small intestine.
-Especially jejunum, upper ileum and less in duodenum.
-Villi tends to be flattened and atrophic.

Early and mild infections:
-Abdominal pain, intestinal gurgling, and chronic watery diarrhoea.

Heavy infections:
-Anorexia, nausea, vomiting & watery diarrhoea(5~10 times/day).
-Death in 2~8 weaks.

Trichuris trichiura - Intestinal Nematodes

Also known as "whipworm", commonly found in tropical & subtropical regions.
Live at human's appendix, anterior part long and thin (about 3/5 length).
*The anterior part often pierce the appendix thus seeing only the tail.
*Tail used to consume the intestinal cell & host's blood.

Diagnostic stage -> Egg in feaces.
Infective stage -> Embryonated egg.

Light infection:
-No recognizable clinical manifestations.
-Discovered only on routine stool examination.
*Anemia, eosinophilia, malabsorption.

Heavy infection:
-Systemic symptoms & gastrointestinal symptoms.
*Nauesa, vomiting, rectal proplase.

Laboratory Diagnosis:
-Find eggs with sigmoidoscopy and proctoscopy in feaces.
-Eggs have to plug on each side.

Enterobius vermicularis - Intestinal Nematode

Also known as pinworm or threadworm -> cause enterobiasis
Commonly found in temperate and tropic regions, child more common infected.

Adult Morphology:
-Light yellow & Three lips
-Cervical alae & Oesphagus bulb

Diagnostic stage -> Eggs on perianal skin
-Eggs -> 6hr -> infective -> remains infective for 2weeks

Infective stage -> Embryonated egg

Transmission:
-Ingestion of infective eggs
-Autoinfection
-Airbrone transmission
-Retroinfection

Laboratory Diagnosis:
-celulose adhesive tape & anal swab

Clinical Features:
-Rarely cause serious symptoms
-Nocturnal anal pruritus

Ectopic migration:
-Granulomatus reaction
-Vagina, fallopian tube, ovary, omentum, lung, urinary bladder, urethra
-Lymph node, liver, spleen, & kidney

Prevention & control:
-Washing anal skin & changing bed cover+clothing
-Personal hygiene
-Group therapy

Human Parasitic Helminthes

Platyhelminthes:

-Trematoda (Flukes)
--Leaf-like, segmented
--Suckers but no hooks, mouth presented
--Digestive tract presented but no anus
--Hermaphrodite

-Cestoda (Tapeworms)
--Tape-like, segmented
--Suckers & hooks, no mouth
--Digestive tract absent
--Hermaphrodite

Nemathelminthes:

-Nematoda (Roundworms)
--Cylindrical, unsegmented
--No suckers or hooks, mouth present
--Digestive tract present with anus
--Separate sexes

Introduction to Nematodes

General morphology:
-Cylindrical.
-Sexes separated (Females usually larger than males).
-Pseudocoel (False body cavity) is presented.

-Body Wall:
--Cuticle:
---Thin, transparent, elastic acellular layer.
---Covering outside of the body.
---Smooth or.. *Ridges *Spines *Ala *Bosses
--Hypodermis:
---Hypodermal chords.
---one dorsal cord, one ventral cord
---Two lateral cord which contains excretory canal
--Somatic muscles
---Polymyrin: A. lumbricoides - 4 side
---Meromyrin: E. Vermicularis - 2 side
---Holomyrin: T. trichiura

Reproductive system
-Male: Copulatory bursa & Spicules

Excretory system

Nervous system

Digestive system:
-Tube-like, independent.
-Dorsal lip x1, Lateroventral lip x2.

Male reproductive system -> one gonad.
Female reproductive system -> one or two gonad.

General biology:
-Monoxeneous -> only one host in life cycle.
-Heteroxeneous -> two or more hosts in life cycle.

Egg->L1&M1->L2&M2->L3&M3->L4&M4->Adult
-Soil-transmitted infection
-Snail-transmitted infection
-Arthropod-transmitted infection

Infective Stages -> L3 & Embryonated Eggs

Drugs for Intestinal Nematode Infections
-Mebendazole & Albendazole

Introduction to Parasite - Life Cycles

-Life cycle:
--Whole life story of parasite.

-Direct life cycle:
--Completed without participation of an intermediate host.

-Indirect life cycle:
--Can only be completed with the participation of intermediate host.

-Infective stage:
--Specific stage in lifecycle of parasites.
--Have ability to initiate an infection in definitive or intermediate host.

-Free-living stage:
--Stage in life cycle where parasites exist free in the general environment.

-Biotic potential:
--Reproductive capacity of the parasite.

-Prepatent period:
--Between "initiation of infection of definitive host" & "appearance of product".

-Incubation period:
--Between "initiation of infection" & "onset of disease".

-Infestation:
--Presence of arthropods on skin of host.

-Infection:
--Presence of parasite in or on the tissue of host.
--May or maynot have deleterious effect on the host.

-Route of infection:
--Route which a parasite gains entry to a host.

-Route of migration:
--Route which some parasites follow in the body of the host.

-Ecdysis:
--Loss of the old cuticle during change of larval stage.
--Also called "Molt" => arthropod & nematodes.

Introduction to Parasitology - Parasites

-Parasite:
--Organism metabolically dependent on another organism.

-Ectoparasite:
--Parasite living on the integument of the host.

-Endoparasite:
--Parasite living in the organs or tissues of the host.

-Obligatory parasite:
--Life cycle can't be complete without a parasitic phase.

-Facultative parasite:
--Life cycle can be completed without a parasiteic phase.
--May optionally include a parasitic phase.

-Aberrant parasite:
--Migrates to or develope in wrong part of the host's body.

-Oviparous parasite:
--Produces eggs which passes out of the body without hatching.
--Undeveloped egg when passed out => unembryonated egg.
--Developed and contains a larva => embyonate egg.

-Viviparous parasite:
--Lays active larvae instead of eggs.

-Ovi-viviparous parasite:
--Lays eggs which hatchs within the body of the host.
--Larvae passes out from the host, not eggs.

Introduction to Parasitology - HOST

-Definitive host:
--Parasite reaches sexual maturity or undergoes sexual reproduction.

-Intermediate host:
--Usually essential to parasite's life cycle.
--Undergoes development to juvenile but not mature stages.

-Vector:
--Carry disease organisms from an infected animal to non-infected animal.
--Biological vector & Mechanical vector

-Paratenic Host:
--Optional to parasite's life cycle.
--Juvenile stage may persist but do not develop.

-Transport host:
--No development occurs & may be shed at any time.

-Reservior host:
--Where parasites maintain in the nature.
--Sources of individual's new cases.

-Abnormal host:
--Can't develope to mature stages.
--Usually found in other host species.