fly vectors mechanical transmission of pathogens
DESCRIPTION
repeated egg batches. eg. Moraxella transmission by Musca or Trypanosoma by tabanids. FLY VECTORS MECHANICAL TRANSMISSION OF PATHOGENS. flies take many meals for each egg batch, thus rapid transmission on contaminated mouthparts. repeated egg batches. - PowerPoint PPT PresentationTRANSCRIPT
FLY VECTORS MECHANICAL TRANSMISSION OF PATHOGENS
flies take manymeals for each egg batch, thus rapid transmissionon contaminatedmouthparts
eg. Moraxella transmission by Musca or Trypanosoma by tabanids
repeated egg batches
FLY VECTORS BIOLOGICAL TRANSMISSION OF PATHOGENS
repeated egg batches
one blood meal per egg batch, pathogen develops internally over ~10 days
eg. encephalitis virus in mosquitoes
FLY VECTORS FLIES COMPARED TO TICKS AS VECTORSsingle female fly
transmission by one female during feeds for repeated egg laying ~ 8 days
larva nymph adult
transmission from stage to stage, one feed per stage, interval 6-18 months
single tick
FLY VECTORS VERTEBRATES AND VECTORS AS RESERVOIRS
January January
seasonal peak of vectors
reservoir host
new reservoir host
disease host
Nos
eg. bluetongue by Culicoides
FLY VECTORS AMPLIFICATION OF VIRUS TRANSMISSION
reservoir host disease host
but insufficient virus in vector
refractory host disease host + plenty virus in vector
vector needs to survive well and feed ofteneg. bluetongue by Culicoides
.
FLY VECTORS DISEASE SPREAD eg. AHS and Bluetongue
AFRICA
increasingly milder winters >> longer midge survival during yearEUROPE
Culicoides imicola in Africa is competentvector of AHS and BT viruses. Spreads far on wind.
• Culicoides obsoletus in Europe could become competent vector under warmer conditions.• Can C.imicola become common in Europe?• Baton effect, virus passes from African midges >> cattle >> European midges
cattle are reservoirs for BTVfor ~200 days
sheep are not carriersafter infection