Ticks

Question 1

What disease to ticks act as a vector of? Describe

Answer 1

Lyme disease
Worlds fastest growing vector-borne condition
Reported in > 60 countries and is endemic now in North America, Asia and Europe
First described in 1977 after a cluster of cases of arthirits in children living in Old Lyme, Conneticut
1981 tick discovered to be host
N.E US often quoted as the endemic centre for Lyme disease

Question 2

How many cases of lyme disease are believed to be reported (%)?

Answer 2

ca. 10%

Question 3

Which ticks harbour Lyme disease in the UK and how many cases are reported?

Answer 3

Ixodes spp.

1,200 confirmed in 2012 up from ca. 300 in 2001

Question 4

Describe the organism which causes Lyme disease

Answer 4

Borrelia burgdoferi

• spirochete bacterium that is sylvatic (humans not main host)
• Infection characterised by bulls-eye rash (60-80% of patients)
• Early symptoms include fever, headache, muscle and joint pain
• Seriou symptoms include cardiac damage, arthritis, cognitive impairment, paralysis and on rare occasions death

Question 5

How is Lyme disease diagnosed and treated?

Answer 5

Serological testing
Treated with antibiotics
No vaccine exists

Question 6

What is the cost of Lyme disease to the US economy?

Answer 6

2.5 billion dollars annually (lost working days, medical costs etc.)

Question 7

Describe the species of ticks that harbour Lyme disease

Answer 7

Ixodes scrapularis and Ixodes pacificus (black legged ticks) in USA
Both male and female ticks vector the bacterium
Ticks feed on rodents, birds, and deer in their natural environment
In ticks the bacterium can be transmitted trans-stadially but not trans-ovarially
Female ticks can lay 1,000-10,000 eggs in their lifetime