Arthropod borne & Zoonotic viral infections-ARBOVIRUSES & Alpha viruses

Question 1

Viruses transmitted from blood sucking athropods (mosquitoes, ticks, and sandflies) to vertebrates (humans)

Answer 1

Arboviruses

Question 2

What are the two widely known alpha viruses?

Answer 2

• Chikungunya virus
• Sindibis virus (Birds are resevoirs: mosquitos get infected by feeding infected blood of birds, and then will infect human by biting them afterwards)

Question 3

Prevalence of arboviruses is expanding,
with these viruses causing >17% infectious diseases globally. What factors aid in wide sread of such infections?

*~135 arboviruses are known to date

Answer 3

• travel,
• trade and
• tourism

Question 4

Genome of arboviruses?

Answer 4

They are RNA

Question 5

Clinical presentation of arboviruses

Answer 5

• febrile illness (ones tht cause an increase in body temp)
• haemorrhagic fever or
• neurological disease

Question 6

The 3 stages of spread of the Arboviruses

Answer 6

1. Pre-emergence
2. Localised emergence
3. Pandemic emergence

Question 7

Pre emergence stage of the Arbovirus infections is aided by what factors?

Answer 7

• Deforestation
• Land use intensification
• Disturbance of habitats

Question 8

localised emergence stage of the Arbovirus infections is aided by what factors?

Answer 8

• Extension of the interphase
• localised outbreaks

Question 9

Pandemic emergence stage of the Arbovirus infections is aided by what factors?

Answer 9

• Urbanisation,
• Global travel and trade
• Sustained person-to-person outbreaks

Question 10

Vector of the Crimean- Congo Haemorragic Fever

Answer 10

Tick

*genus hyelomma

Question 11

The modes of transmission of Crimean-Congo Haemorragic Fever

Answer 11

• Animal to animal transmission (animals of concern: rabbits, birds, rodents, cattle, sheep, goats and ostriches):
  -through bite from infected tick
  -through direct contact of bodily fluids of infected animal
• Animal to human transmission:
  -Through bite from infected tick
  -Direct contact with the blood or organs of infected animals
• interhuman transmission (human to human):
  -through direct contact with the blood and other bodily fluids,
  secretions and organs of an infected person

Question 12

A viral infection presenting symptoms to humans, but remains asymptomatic in animals

Answer 12

Crimean-Congo Haemorragic Fever

Question 13

Vector of Rift Valley Virus

Answer 13

mosquitos

• particulary: (Aedes, Culex and Anopheles)

Question 14

This virus has a reservoir, and a reservoir is a wild herbivore

Answer 14

Rift valley fever

Question 15

Different modes of transmissions of rift valley fever

Answer 15

• Animal to animal transmission
  through:
  -Mosquito bites
  -Contact with infected bodily secretions esp blood
• Human transmissions
  through:
  -mosquito bites
  -Direct contact with the blood or organs of infected animals
  -Consumption of raw/ undercooked meat or unpasteurised dairy products

*Here we do not have ‘human to human’ transmission

Question 16

Environmental conditions favouring prevelance or occurance of rift valley fever

Answer 16

• Heavy rainfall
• Unseasonably warm temperatures

*They favour mosquito breed and their activity

Question 17

What are principal symptoms of rift valley fever in humans?

Answer 17

• Flu like symptoms
• More severe:
  -Bloody vomiting,
  -loss of vision and
  -neurological complications

Question 18

Warning signs seen in animals that rift valley fever might be taking place

Answer 18

• High mortality in animals
• Large scale Arbortion
• High fever – other signs such as anorexia (leads to low body weight), jaundice, diarrhoea and nasal discharge

Question 19

People at risk for rift valley fever infection

Answer 19

• people who raise animals,
• vets,
• agricultural and slaughterhouse workers

Question 20

A viral infection transmitted to humans through bite of mosquitos. But we have different species of mosquitos transmitting disease in urban areas, as well as in forests

Answer 20

Yellow fever

*Mosquitos transmitting disease in forests- Haemagogus and Sabethes species_(sylvatic cycle)
* In urban areas: Aedes aegypti_(urban cycle)

Question 21

What is a mosquito-borne fever from a female Aedes mosquito.

Answer 21

Dengue fever

Question 22

Symptoms of Dengue fever

Answer 22

• Severe headache,
• high fever,
• pain behind the eyes,
• nausea and vomiting,
• swollen glands/rash,
• muscle and joint pains
• and chills

Question 23

What are the sever dengue signs?

Answer 23

• severe bleeding and
• respiratory distress

Question 24

What’s the vector of Zika virus?

Answer 24

mosquito

Question 25

what are the transmission routes of Zika virus?

Answer 25

• Mother to Child transmission
• Sexual transmission
• Blood transfusion

Question 26

What are the possible symptoms seen with Zika virus?

Answer 26

Rash, headache, fever, itchy eyes

Question 27

How are alpha viruses transmitted to humans?

Answer 27

Via mosquito bites

Question 28

What are possible symptoms of Chikungunya virus?

Answer 28

• Joint and Back pain,
• rash,
• headache,
• chills,
• vomiting,
• fever,
• nausea

Question 29

An alpha virus causing non- specific febrile illness: defined by rash and arthralgia (joint pain)

Answer 29

Sindibis virus

Question 30

Treatment for Sindbis viral infection

Answer 30

• Antihistamines for itchy rash