Vector-borne diseases

vector-borne disease definition

infectious diseases caused by pathogens that are transmitted by arthropods or other invertebrate, biologic intermediaries

transmission of vector-borne pathogens usually occurs during…

blood feeding by an infected insect or acarine parasites

infection with vector-borne agents can also results when…

a vertebrate host ingests a vector, or on contamination of a wound by the feces

transstadially

when the vector maintains the infection as they molt from immature to mature form

transovarially

when the vector passes the organism from the female to the offspring

amplifying host

the arthropod infects a vertebrate that can develop a short-lived infection capable of infecting the rest of the vector population

bridge vector

the arthropod is required to actually bring the infection from the wildlife reservoir host to companion animals, livestock, or people

transmission rate

the number of new infections that occur per unit time

Togaviruses example

eastern equine encephalitis

resevoir host of eastern equine encephalitis

birds

vector of eastern equine encephalitis

mosquitos

definitive host of eastern equine encephalitis

horses

is eastern equine encephalitis zoonotic

yes it can infect humans

eastern equine encephalitis infection with humans

can cause meningitis

flavivirus example 

west nile virus

reservoir host of west nile virus

birds

vector of west nile virus

mosquitos

is west nile virus zoonotic

yes it can infect humans

who is the vector for the WNV rodents

ticks

who is the vector for the WNV primates and birds

mosquitos

Bunyavirus example

Rift Valley Fever

rift valley fever can cause

abortions and mortality

is rift valley virus zoonotic

yes it can infect humans

transmission of rift valley virus in mosquitos

transovarially

reovirus example

Blue tongue

species affected by blue tongue

ruminants (cow)

vector of blue tongue

mosquitos/midges

blue tongue infection causes

fever, abortion, circulation problems

how many strains of blue tongue

16

the blue tongue virus is not spread directly from 

infected tissues or body fluids

blue tongue disease is more prevelant in

warm and temperate regions

Tick borne disease example

rocky mountain spotted fever

pathogen of rocky mountain spotted fever

Rickettsia rickettsii

vector of RMSF

american dog tick 

transmission of RMSF infection

transovarially and trasstadially

the tick population serves as both the

reservoir and vector of the pathogen

what cells are damaged from RMSF

endothelial cells resulting in progressive necrotic vasculitis

thrombocytopenia

low platelets

people with RMSF often develop a

non-pruritic rash “spots” 3-4 days after initiation of fever

fatalities can follow

severe meningitis or meningeencephalitis

to be passed onto a dog, an infected tick must be feeding for

5-20 hours

symptoms of the infection may develop within

2 days to 2 weeks

risk of transmission to people in they come in contact with

the feces or saliva from an infected tick

if treatment is started early in the disease, dogs typically recover fully and may develop

life-long immunity

how long to treat for RMSF

3-4 weeks doxycycline

silent domestic disease example

murine typhus

is murine typhus zoonotic

yes it can infect humans 

the vector of murine typhus is

the cat/rodent flea

big host of murine typhus

cat