Detection of West Nile virus using formalin fixed paraffin embedded tissues in crows and horses: quantification of viral transcripts by real-time RT-PCR.

The research article highlights the quantification of West Nile virus (WNV) RNA in infected crows and horses through real-time reverse transcriptase-PCR assay. It found that crows had more viral RNA than horses, with the highest amounts present in the intestines and brains respectively.

Methodology

• The researchers used a real-time reverse transcriptase-PCR assay to detect and quantify West Nile virus RNA in infected crows and horses. This procedure enabled them to measure the amount of WNV RNA present in these species.
• To accomplish this, they used a 5′ nuclease assay with a fluorescent probe. This type of assay is a highly sensitive and specific method for detecting and quantifying nucleic acids. In this case, the assay was based on the detection of the NS5 gene, which is one of the key viral genes involved in the replication of the West Nile virus.
• The tissue specimens used for the assay were formalin-fixed paraffin-embedded specimens, which preserves tissues for examination by keeping their structure intact and preventing degradation.

Findings

• By quantifying the detected WNV RNA, the researchers found that there was a higher amount of the viral RNA in tissues from crows as compared to tissues from horses. This could suggest that crows have a higher viral load or are more susceptible to infection than horses.
• The results from the quantification correlated well with the detection of the WNV antigen by a method known as immunostaining. This technique involves the use of antibodies to detect specific antigens associated with the virus, therefore confirming the presence of the virus.
• The research also identified the areas of highest viral load in each species: the intestine in crows and the brain in horses. This could indicate a difference in how the virus behaves biologically within different species or in different tissue environments.

Implications

• The findings of this research could be useful in understanding the spread and effect of the West Nile virus in different species. The information about the virus’s prevalence in different tissues can shed light on its pathogenesis (how it causes disease).
• Quantitative detection of WNV RNA through real-time reverse transcriptase-PCR could offer a reliable method to monitor viral load in different hosts, which can support strategies for controlling the spread of the virus.
• Knowing the areas of highest viral concentration in different species can also contribute to developing treatment strategies. For instance, if a particular organ is most affected, treatment can be tailored to target that organ.