Arthropod borne & Zoonotic viral infections-ARBOVIRUSES & Alpha viruses Flashcards
(30 cards)
Viruses transmitted from blood sucking athropods (mosquitoes, ticks, and sandflies) to vertebrates (humans)
Arboviruses
What are the two widely known alpha viruses?
- 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)
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
- travel,
- trade and
- tourism
Genome of arboviruses?
They are RNA
Clinical presentation of arboviruses
- febrile illness (ones tht cause an increase in body temp)
- haemorrhagic fever or
- neurological disease
The 3 stages of spread of the Arboviruses
- Pre-emergence
- Localised emergence
- Pandemic emergence
Pre emergence stage of the Arbovirus infections is aided by what factors?
- Deforestation
- Land use intensification
- Disturbance of habitats
localised emergence stage of the Arbovirus infections is aided by what factors?
- Extension of the interphase
- localised outbreaks
Pandemic emergence stage of the Arbovirus infections is aided by what factors?
- Urbanisation,
- Global travel and trade
- Sustained person-to-person outbreaks
Vector of the Crimean- Congo Haemorragic Fever
Tick
*genus hyelomma
The modes of transmission of Crimean-Congo Haemorragic Fever
- 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
A viral infection presenting symptoms to humans, but remains asymptomatic in animals
Crimean-Congo Haemorragic Fever
Vector of Rift Valley Virus
mosquitos
- particulary: (Aedes, Culex and Anopheles)
This virus has a reservoir, and a reservoir is a wild herbivore
Rift valley fever
Different modes of transmissions of rift valley fever
- 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
Environmental conditions favouring prevelance or occurance of rift valley fever
- Heavy rainfall
- Unseasonably warm temperatures
*They favour mosquito breed and their activity
What are principal symptoms of rift valley fever in humans?
- Flu like symptoms
- More severe:
-Bloody vomiting,
-loss of vision and
-neurological complications
Warning signs seen in animals that rift valley fever might be taking place
- High mortality in animals
- Large scale Arbortion
- High fever – other signs such as anorexia (leads to low body weight), jaundice, diarrhoea and nasal discharge
People at risk for rift valley fever infection
- people who raise animals,
- vets,
- agricultural and slaughterhouse workers
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
Yellow fever
*Mosquitos transmitting disease in forests- Haemagogus and Sabethes species_(sylvatic cycle)
* In urban areas: Aedes aegypti_(urban cycle)
What is a mosquito-borne fever from a female Aedes mosquito.
Dengue fever
Symptoms of Dengue fever
- Severe headache,
- high fever,
- pain behind the eyes,
- nausea and vomiting,
- swollen glands/rash,
- muscle and joint pains
- and chills
What are the sever dengue signs?
- severe bleeding and
- respiratory distress
What’s the vector of Zika virus?
mosquito
