Arboviruses Flashcards
Define Arbovirus.
Arthropod borne virus, capable of replicating in the gut and salivary glands of insect vector and the host.
Factors affecting arbovirus infection?
Weather/climate, predators, food/space.
Ross River Virus characteristics?
Famliy:Togaviridae, Genus:Alphavirus, (+)ssRNA, icosahedral shell, lipid bilayer. RME.
Clinical outcome of Ross River virus infection.
Incubation of 3 days - 3 weeks. Fever chills, muscle aches, headache -> disabling rheumatic symptoms; joint pain, swelling, stiffness.
Treatment of Ross River Virus?
No specific antivirals, no vaccine, just paracetamol for pain/fever.
Dengue Virus Characteristics?
Family: Flaviviridae, Genus: Flavivirus, (+)ssRNA, icos. NC, lipid envelope. 4 Subtypes (DENV 1-4, DENV-2 most severe). Forms single protein, buds into ER
Clinical disease of Dengue fever?
INITIAL infection: mild, asymptomatic. Secondary infection: Rash, fever, chills, headache, severe abdo. or back pain, muscles and joints ache. OR Dengue haemorrhagic fever/Dengue Shock syndrome.
Explain Dengue Haemorrhagic fever.
Fever + Headache + resp./GIT symtpoms AND haemorrhage (bruising, stool, gums, nosebleeds leading to shock.)
Cells targeted by dengue?
Monocyte lineage (reticuloendothelial system/dendritic cells), endothelial cells (cause increased capillary permeability.)
Antibody role in Dengue infection?
Antibodies are produced by initial infection to a single serotype. When infected with another serotype, the antibodies activate the immune system, however are not protective against the virus. This prevents more appropriate antibodies from being produced (antigenic sin). Leads to overt immune reaction, which effects blood vessels.
Treatment of Dengue?
Fluid replacement. In the future there may be antivirals or cytokine therapy. Any vaccine produced must be equally protective against all serotypes, to prevent cross-reactivity.
Ways to control Mosquito, and therefore Arbovirus spread?
Mosquito nets, fumigation, prevention of breeding sites, sterilisation?
