Findings in cerebrospinal fluids of horses infected with West Nile virus: 30 cases (2001).

The research assesses the cerebrospinal fluid (CSF) in horses infected with West Nile virus encephalomyelitis to understand the likely abnormalities. The findings illustrate a majority of abnormal samples, with mononuclear pleocytosis and lymphocytic predominance being common. CSF collected from the lumbosacral region was found to be more frequently abnormal than from the atlanto-occipital region.

Study Methodology

• The study is retrospective in nature, implying that the researchers used previously collected data to understand the potential patterns and implications.
• The study involved the analysis of cerebrospinal fluid (CSF) from 30 horses. These horses exhibited acute neurological signs due to infection from the West Nile Virus. The infection was confirmed via immunoglobulin M antibody capture ELISA, a commonly used diagnostic tool for detecting antibodies against viruses in the blood.

Findings

• Among the 30 CSF samples that were analyzed, 27% were within the reference ranges, whereas 73% were abnormal, marking a significant majority.
• Of the 22 abnormal samples detected, 16 (73%) showed mononuclear pleocytosis, which is an increase in white blood cells with a single round nucleus in the CSF. This condition usually signals inflammation of the central nervous system.
• Of these 16 samples that had mononuclear pleocytosis, a predominance of lymphocytes (a type of white blood cell that plays a key role in the immune response) was observed in 11 samples, and large mononuclear cells were predominantly observed in the remaining 5.
• In 6 samples (27%), normal nucleated cell counts were accompanied by high protein concentration. This condition is often associated with neurological disorders or trauma in the brain or spinal cord.

Sensitivities of Analyses

• The analysis revealed that the lumbosacral region of the spinal cord had a higher probability of showing abnormalities in the CSF (with a sensitivity of 89%), compared to the atlanto-occipital region which showed a sensitivity of 50%.

Conclusions

• The research concludes that horses with acute onset of neurological signs caused by the West Nile Virus encephalomyelitis are likely to have abnormal CSF results. Of these abnormalities, the most common is mononuclear pleocytosis with lymphocytic predominance.
• Moreover, the CSF collected from the lumbosacral region of the spinal cord was more likely to show abnormalities than that collected from the atlanto-occipital region.