1746436
Description
Flashcards by Thalia Groom, updated more than 1 year ago
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Created by Thalia Groom
about 10 years ago
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| Question | Answer |
| What are the two most important reasons for the spread of plant pathogens? | 1. Introduction 2. Weather |
| List four ways that global warming will affect vector-bourne disease | Increased vector development Prolonged favourable conditions Increased winter survival Increaed geographical range |
| In what decade began the pole-ward shift of pests? | 1960s |
| List 3 caveats to the pole-ward shift of pathogens | 1. Richer countries detect pathogens sooner 2. Agricultural varieties have increased range of hosts 3. Geographical barriers such as the Sahara desert may effect southward movement |
| Why do countries at greater latitudes have to increase surveillence? | Greatest productivity per area |
| Why will rate of mortality also increase in pathogens due to global warming? | Increased number of their predators |
| Give an example of which warmer winters will negatively effect the parasite and where will this occur? | Nematodes Temperate areas |
| Give an example of which global warming will positively effects pests and where will this occur? | Larvae Colder climates |
| When are ewes most susceptible to blow fly strike and why? | During the spring and summer because of their wet/soiled fleeces |
| How can the susceptibility of blowfly strike be reduced? | sheering |
| Why are lambs more susceptible to blow fly strike after sheering? | Growing fleeces and GI nematode infections |
| What effect does global warming have on the presence of blowfly? | Strikes occur earlier in the year and the blowfly population will be larger |
| What can be done to prevent earlier blow fly strikes? | Sheer sheep earlier i.e. early April |
| How does the medium risk model predict prevalence of malaria in 2050? | Increased risk for 23 million people |
| How does the high-risk model predict outcome of malaria in 2050? | Decreased risk for 25 million people |
| List 3 animals affected by bluetongue | Mostly common in fine-wool sheep Also ruminents like white-tailed deer Sporadic in cattle |
| List 5 symptoms of bluetongue | fever depression lameness oedema of lips conjunctivitis |
| List four outcomes of BT | Decreased fertility Decreased milk-yeild Weight loss Wool break |
| What cells of the sheep does the virus infect intitially? | Mid gut cells |
| After replication where does the virus relocate to? | Haemocoel |
| After that, where does the virus infect and replicate? | salivary glands |
| What is meant by the term extrinsic incubation period? | Time from ingestion to the salivary glands |
| How is the blue-tongue spread? | vector-bourne midges - culicoides |
| What type of virus is BTV? | DS-RNA |
| How many RNA segments does BTV have? | 10 |
| What 3 structure make up the viral shell? | sub-core, outercore, and outercapsid |
| What structural proteins make up the outercapsid and determine the serotype? | VP2 AND VP5 |
| How many serotypes of BTV are there? | 24 |
| What process can cause antigenic shift in BTV? | Genetic reassortment |
| Name three species of culicoide midges and where they are distrubuted | C.imicola - Africa C.sonorensis - N.America C.brevitarsis - Australia |
| What enzyme largely controls the time between blood meal and a new infection? | RNA Polymerase |
| What is the optimum temp for this enzyme? | 30 degrees - few days |
| What happens to the course of infection over winter? | Infection stops |
| What is the name given to the emergence of parasitism after its disruption during winter? | overwintering |
| Where and when was BTV first described? | 1905 in South Africa |
| What year and where was the non-African outbreak? | Cyprus 1943 |
| Before 2005, what was the most severe outbreak of BTV in southern Europe? | 1956 - Iberia 180 000 animals died |
| What 5 serotypes are present around the Mediterranean basin? | 1,2,4,9,16 |
| What was the traditional vector for BTV? | c.imicola |
| What species were isolated from traps in Italy? | C.pulcaris C.obsoletus |
| Which countries successfully implemented a vaccine against which strain of BTV? | SPAIN AND PORTUGAL BTV-1 |
| What serotype caused the first ever outbreak in northern europe and where? | serotype 8 netherlands |
| How was this outbreak stopped? | Winter of 2007 haulted transmission |
| Give 2 reasons thought to be the cause for the BTV-8 outbreak? | Movement of infected animal or vectors Illegal african vaccine was used containing live virus |
| What event occurred that lead to a new outbreak of BTV in June 2007? | Virus overwintered in Germany |
| What was the economical burden of the BTV? | 60000 farms affected costing >150 million euros |
| What allowed UK to be declared BTV-8 free in 2008? | They opted for the attenuated BTV vaccine |
| Give four reasons why the BTV-8 outbreak was so disastrous | Never seen BTV or traditional vector before Very mild climate Lax vaccination attitude No programme monitoring Culicoides |
| List two other diseases spread by cullicoides | Epizootic haemorrhagic disease African horse sickness |
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