SNC4M- Parasites

Vector

Biting bug

Primary host

Host that a parasite needs to become sexually mature to reproduce

Intermediate host

Sometimes used as transportation/vessel for growth before going back to primary host

Ectoparasite

Lives outside of the host’s body

Endoparasite

Lives inside the host’s body

Chain of infection target #1

Susceptible host

NTD

Neglected Tropical Disease

Ways that parasites evade the immune system

• Can live in veins

• Can cover itself with body proteins

• Can change shape and bury antigens

• Can kill antibodies

• Can hide within macrophages

• Can be anti-inflammatory (suppresses immune response)

Antiparasitic drugs

• Drugs meant to kill & inhibit growth of parasitic organisms

• Very specific to parasite, unlike broad spectrum antibiotics (Parasites are eukaryotic)

Immunoglobulins

Y shaped proteins produced in B-cells

IgG antibody

• Account for 80% of antibodies

• Number increases as infection progresses

IgA antibody

Found in glandular secretions

Glandular secretions

Fluid released by glands (saliva, semen, sweat, milk)

IgM antibody

Anti-A and Anti-B antibodies

IgE antibody

Responsible for fighting parasitic infection

Allergies

“inappropriate immune response”

Mast Cells

• Produce inflammation

• Allergic reactions occur where mast cells are present

Histamines

Powerful chemical released to kill parasites - also released in allergic reactions, damages your body cells

Antihistamines

Drugs to combat allergy symptoms

Chain of infection target #2

Means of transmission

Preventing the cycle of parasitic infection

• Bug spray

• Avoiding biting times

• Don’t settle villages by rivers

Chain of infection target #3

Reservoirs

Vector control - Issues

• Too costly

• Some vectors may be missed → reproduction

• Gradual resistance to insecticide

Sleeping sickness

Trypanosomiasis

River blindness

Onchocerciasis

Guinea worm

Dracunculiasis

Bilharzia

Schistosomiasis

Trypanosoma Brucei

Comes from Africa, from Tse-Tse Fly saliva

Trypanosoma Cruzi (chagas disease)

Comes from central america, from vector feces