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Volume 32, Number 5—May 2026
Dispatch
One Health Investigation into Fatal Encephalitis caused by Pigeon Paramyxovirus Type 1, France
Figure 3
![PPMV-1 dissemination in the central and peripheral nervous systems and in axillary lymph nodes in a patient with fatal PPMV-1 encephalitis in France. A) Schematic representation of PPMV-1 viral load in 30 postmortem tissue samples; complete list of all samples is provided (Appendix Table 3, https://wwwnc.cdc.gov/EID/article/32/5/25-1576-App1.pdf). Viral loads were estimated at 5.2 × 105−2.6 × 106 genome copies/gram of tissue in the midbrain and 1.1−5.5 × 105 genome copies/gram of tissue in the cervical spinal cord. B) PPMV-1 viral burden in different anatomic compartments. Samples were classified into 6 groups: group 1, forebrain (including telencephalon and diencephalon); group 2, midbrain; group 3, hindbrain (including metencephalon and myelencephalon); group 4, spinal cord and spinal ganglion; group 5, lymph nodes; group 6, peripheral nervous system and peripheral samples. For the 17 forebrain samples (group 1), the PPMV-1 Ct values were the lowest (median 19.76 [IQR 16.90–25.62]), reflecting the highest viral burden. A Ct value >30 was observed in only 2 forebrain samples, the choroid plexus (Ct = 32.2) and the pituitary gland (Ct = 33.85). The 3 midbrain samples (group 2) and the 2 hindbrain samples (group 3) had higher Ct values: medians 24.05 (IQR 23.77–25.63) and 24.17 (IQR 21.33–27.00). Ct value further increased in the subsequent groups: medians 30.91 (IQR 27.49–34.39) in the 4 spinal cord and 2 spinal ganglion samples (group 4) and 36.49 (IQR 36.06–36.92) in the 2 axillary lymph node samples (group 5), indicating a progressive decrease in viral burden. The last group, consisting of 17 samples (group 6) including peripheral nervous system samples and 5 peripheral samples were all negative. We conducted a nonparametric Kruskal-Wallis test that indicated differences among groups (p<0.0001). Posthoc tests revealed an increasing trend in PPMV-1 Ct value from the brain to the peripheral samples. Pairwise Wilcoxon tests (2-tailed) for differences in means between groups adjusted with Bonferroni correction are displayed. Nonsignificant p values (>0.05) are not shown. Horizontal line within boxes indicate medians, box tops and bottoms represent IQRs, and whiskers indicate minimum and maximum values. Ct, cycle threshold; IQR, interquartile range; PPMV-1, pigeon paramyxovirus type 1.](/eid/images/25-1576-F3.jpg)
Figure 3. PPMV-1 dissemination in the central and peripheral nervous systems and in axillary lymph nodes in a patient with fatal PPMV-1 encephalitis in France. A) Schematic representation of PPMV-1 viral load in 30 postmortem tissue samples; complete list of all samples is provided (Appendix Table 3, https://wwwnc.cdc.gov/EID/article/32/5/25-1576-App1.pdf). Viral loads were estimated at 5.2 × 105−2.6 × 106 genome copies/gram of tissue in the midbrain and 1.1−5.5 × 105 genome copies/gram of tissue in the cervical spinal cord. B) PPMV-1 viral burden in different anatomic compartments. Samples were classified into 6 groups: group 1, forebrain (including telencephalon and diencephalon); group 2, midbrain; group 3, hindbrain (including metencephalon and myelencephalon); group 4, spinal cord and spinal ganglion; group 5, lymph nodes; group 6, peripheral nervous system and peripheral samples. For the 17 forebrain samples (group 1), the PPMV-1 Ct values were the lowest (median 19.76 [IQR 16.90–25.62]), reflecting the highest viral burden. A Ct value >30 was observed in only 2 forebrain samples, the choroid plexus (Ct = 32.2) and the pituitary gland (Ct = 33.85). The 3 midbrain samples (group 2) and the 2 hindbrain samples (group 3) had higher Ct values: medians 24.05 (IQR 23.77–25.63) and 24.17 (IQR 21.33–27.00). Ct value further increased in the subsequent groups: medians 30.91 (IQR 27.49–34.39) in the 4 spinal cord and 2 spinal ganglion samples (group 4) and 36.49 (IQR 36.06–36.92) in the 2 axillary lymph node samples (group 5), indicating a progressive decrease in viral burden. The last group, consisting of 17 samples (group 6) including peripheral nervous system samples and 5 peripheral samples were all negative. We conducted a nonparametric Kruskal-Wallis test that indicated differences among groups (p<0.0001). Posthoc tests revealed an increasing trend in PPMV-1 Ct value from the brain to the peripheral samples. Pairwise Wilcoxon tests (2-tailed) for differences in means between groups adjusted with Bonferroni correction are displayed. Nonsignificant p values (>0.05) are not shown. Horizontal line within boxes indicate medians, box tops and bottoms represent IQRs, and whiskers indicate minimum and maximum values. Ct, cycle threshold; IQR, interquartile range; PPMV-1, pigeon paramyxovirus type 1.
1These authors contributed equally to this article.
2These senior authors contributed equally to this article.