Arthropods as vectors of infectious diseases

Question 1

explain Hematophagous arthrodes

Answer 1

Hematophagy = feeding on blood – blood of vertebrates

Specific mouth parts and chemicals needed.

Can be obligatory or facultative form of feeding.

Question 2

How do Hemaphagious arthropods find their food (victim)?

Answer 2

Hemaphagious arthropods mainly use olfactory signals to find food:

CO2, lactic acid, acetone, ammonia, butanon, fatty acids, compounds of phenols, urine and heat.

Have partial visual abilities, carry special receptors.

Question 3

In Latin vector means

Answer 3

carrier

Question 4

2 Types of vectors

Answer 4

Biological vectors
Mechanical vectors

Question 5

explain Biological vectors

Answer 5

such as mosquitoes and ticks, may carry
pathogens that have to multiply or develop within their bodies and be delivered to new hosts, usually through biting.

Question 6

Explain Mechanical vectors

Answer 6

such as filth flies, can pick up infectious
agents on the outside of their bodies and transmit them through physical contact.

Question 7

Pathogens that can be transmitted via vector, bacteria. (4-5)

Answer 7

francisella tularensis
borrelia spp.
bartonella spp.
rickettsias: anaplasma & ehrlichia

Question 8

Pathogens that can be transmitted via vector, protozoa. (5)

Answer 8

babesia
theileria
plasmodium
leishmania
trypanosoma

Question 9

Pathogens that can be transmitted via vector, helminths. (5)

Answer 9

wuchereria bancrofti
dirofilaria
onchocerca colcolus
mansonella
pipylidium caninum

Question 10

Arthropod vectors of disease can broadly include what types of arthropoda?

Answer 10

mosquitoes
flies

lice
fleas

ticks

(NOT bedbugs)

Question 11

Examples of tick-borne infections in Estonia

Answer 11

Virus:
* Tick-borne encephalitis (Flaviviridae) TBE

Bacteria:
* Francisella tularensis (natural reservoirs in Northern-Estonia)
* Borrelia burgdorferi / Lyme disease/ borreliosis
* Anaplasma phagocytophilum (= Ehrlichia phagocytophila)

Protozoa:
* Babesia spp.

Question 12

Describe Tick-borne encephalitis

Answer 12

TBEV plays an important role in human morbidity in Europe and in Estonia in particular.

• All three known TBEV subtypes, Western (W-TBEV), Far-Eastern (FE-TBEV), and Siberian (S-TBEV), co-circulate in
  Estonia.

Question 13

Describe Tick borne borreliosis

Answer 13

Causal agents of Lyme disease:
Spirochetes from Borrelia burgdorferi sensu lato complex (a diverse group of bacteria spp.):

B. afzelii,
B. garinii,
B. spielmanii ja
B. burgdorferi sensu stricto (strictly)

+ B. valaisiana and B. lusitaniae potential additional pathogens

• General prevalence of B. burgdorferi was 9.7%, varying from 4.9% to 24.2% in the mainland of Estonia.
• Vector Ixodes persulcatus was more often infected than I.ricinus!

Question 14

Q-fever is caused by

Answer 14

bacterium Coxiella burnetii

Question 15

Filariosis in Northern Finland

Answer 15

• Setaria tundra microfilariae in reindeer and other cervids in Finland (Laaksonen et al. 2009).
• Related directly with the mosquito population density.

Question 16

describe Tularemia

Answer 16

• bacterium Francisella tularensis
• Endemic on the uninhabited Pakri Islands of the northern coast of Estonia.
• Reservoirs in nature: water-vole, different mice species.
• Isolated in Estonia from Aedes mosquitoes (1998).

Question 17

Describe Malaria

Answer 17

• blood protozoan Plasmodium vivax
• Disappeared in Estonia in 1949
• Vector restricted to Anopheles mosquitoes.
• Plasmodium vivax – most Northern spp.
• P. falciparum – tropical, most dangerous.
• P. malariae – Northern border in Eur 53. parallel of latitude.
• P. ovale – only in Africa
• In wildlife, over 50 species of plasmodiums, humans not affected.

Question 18

Importance of vectors

Answer 18

• WHO: Vector-borne diseases account for more than 17% of all infectious diseases, causing more than 1 million deaths
  annually.
• Mosquitoes are the best known disease vector.
• Others include ticks, flies, sandflies, fleas, triatomine bugs and some freshwater aquatic snails.

Question 19

Which trait of infected honey bees are manipulated by parasitic phorid fly Apocephalus borealis?

Answer 19

Behaviour

Question 20

Are Bedbugs considered as notable disease vectors?

Answer 20

no