Presentation 2: Monitoring Silent Spillovers Before Emergence

Question 1

What was the hypothesis of this study?

Answer 1

Tick borne viruses are silently crossing the barrier and infecting humans or domestic animals living in regions where they are in close contact with ticks

Question 2

What was the goal of the study?

Answer 2

Evaluate the ability of the strategy that consists in coupling HTS with serological screening to see which species are crossing the barrier and which are not

Question 3

What are the steps of vertebrate pathogen into new vertebrate species?

Answer 3

1) Spillover of a pathogen from its animal reservoir
2) Interhuman transmission of a zoonotic pathogen
3) Large-scale spread of a zoonotic pathogen by humans
4) Adaptation of pathogen to humans

Question 4

What is the concern with climate change?

Answer 4

Ticks becoming more widespread, exposure of pathogens to new regions

Question 5

What does High Throughput sequencing do?

Answer 5

Allows to gain knowledge of what infectious agents the ticks are spreading
Can be used as a method to monitor spillover events
Used because viruses have been detected in species, but the zoonotic risk is still unknown

Question 6

What were the methods employed in this paper?

Answer 6

Tick collection: 266 (18 males, 197 females, 51 nymphs) in Thailand
Human serum samples: voluntary collection
Cattle serum samples: 70 cattle
High-throughput Sequencing of Tick Viriome: Over 222 million raw reads
Used BLAST
Obtained ORFS, RNA reverse transcribed, and PCR
Serological screening of humans and cattle: targeted viral external proteins
Statistical Analysis

Question 7

What were the first results in this study?

Answer 7

Sequences were in eukaryotic domain 
Bacteria: 0.09% and viruses 0.001% 
Over 99% were RNA viruses: 
-ssRNA: 97.20%
\+ssRNA: 1.94% 
Unclassified: 0.70% 
dsRNA: 0.14%

Question 8

What were the second results in this study?

Answer 8

Six viral genomes identified
BLTV4: vertebrates/insects: +ssRNA 
WhTV1: Plants/invertebrates: -ssRNA 
LTPV: Insect: -ssRNA
Thailand tick thogotovirus: vertebrates/invertenrates: +ssRNA
WhTV2/CpTV2: invertebrates: -ssRNA

Question 9

What is the prevalence for the viral genomes?

Answer 9

BLTV4: 19%
WhTV2: 18%
LTPV: 21%
WhTV1: 21%

Question 10

What were the third results of this study?

Answer 10

LIPS based serological screening
Viruses capable of infecting mammalian species were tested in humans and cattle
No significant difference between exposed and unexposed groups when it came to the tick/human contact