Week 7: Vector Borne Diseases

vector borne diseases

Infectious diseases caused by pathogens or parasites transmitted to humans via insects (e.g. mosquitoes, tsetse flies) or other invertebrates (e.g. snails); infected individuals are not directly infectious to other people; some vector-borne diseases also have reservoirs of infection in non-human vertebrates (i.e. they are zoonoses).

Eastern Equine Encephalitis Virus (EEEV)

Virus that infects horses and other mammals via bird vectors, is spreading due to climate change

Lyme disease

Illness caused by the Borrelia burgdorferi virus

Borrelia burgdorferi

virus that causes lime disease, carried by ticks

Borrelia burgdorferi transmission

Vector borne via ticks from animal hosts
possibly transplacental

signs and symptoms of lyme disease

begins 3-30d post bite Early localized infection: growing bulls-eye rash at site of tick bite, lymph node enlargement, flu-like symptoms.
severe cases can have permanent symptoms such as memory loss, meningitis, brain fog, neuropathy, facial paralysis, lyme carditis, arthritis, severe myalgia and perfuse rash, even leading to death if left untreated

west nile

disease caused by the west nile virus

west nile virus

virus that uses mosquitos as a vector between birds and humans

west nile spread

bird to human via mosquitoes
human to human with blood exchange
transplacental and through breastmilk

west nile in canada

becoming an increasing problem with climate change and more favourable mosquito environments

signs and symptoms of west nile

can be asymptomatic in 70-80% of those infected
onset 2-15 days post infection including rash, myalgia, fever and headache
severe symptoms include paralysis, high fever, weakness, difficulty swallowing, which may be permanent

Malaria

disease caused by the parasites Plasmodiums

Plasmodiums

parasitic family that causes malaria
includes p. falciparum and p. vivax, p. malariae, p. knowlesi

P. falciparum

species of Plasmodium that causes the most severe cases of malaria

p. vivax

most common form of malaria

signs and symptoms of malaria

begin 10-15 days post infection
mild: fever, chills, headache
p. falciparum infection; extreme myalgia, fatigue, decreased LOC, resp. distress, AKI, liver disease,
and high fever leading to seizures, death within 24hrs of onset

Malaria treatment

Artemisinin Combination Therapy (only works on p. falciparum), choroquine (only works on p. vivax) and primaquine (can be added to regimens to prevent relapse)
but resistance is increasing steadily to meds

malaria vaccine

RTS,S for children in p. falciparum endemic areas
Matrix-M (R21)

Malaria chemoprophylaxis

preventative administration of medications before travelling to endemic areas for high risk groups

malaria prevention

Physical: mosquito nets, insect repellants, clothing
vaccination and prophylaxis medication
eradication with genetic modification

climate change is predicted to impact VBD frequency and distribution in three ways:

- poleward spread
- re-emergence of endemic VBDs
- emergence of exotic VBDs (malaria)

neglected tropical diseases

diseases that affect people primarily in the poorest areas of the world in which housing, sanitation, and water supplies are deficient

i.e., hookworm, malaria, typhus