Explore the vast range of titles available.

Herpes B virus (B virus) is an enigmatic zoonotic virus that has caused severe neurologic symptoms in humans exposed to captive macaques used for experimentation. We examined 864 wild long-tailed macaques from 22 locations across Thailand for B virus infection. All 22 macaque populations tested positive for B virus antibodies; seropositivity ranged from 25% to 100%. B virus shedding was detected in 9 (1.04%) oral swab samples by using quantitative PCR of the virus UL29 gene. We phylogenetically analyzed partial genome sequences of B virus (US5-US6 genes) from 6 of the PCR-positive samples. All 6 sequences were clustered in clade II, which includes B virus strains from rhesus, Japanese, and long-tailed macaques, suggesting co-evolution of B virus with macaques. Continued surveillance and sequencing of B virus in macaque populations will be needed to prevent B virus transmission to humans and to develop appropriate vaccines to prevent human B virus infections.

Herpes B virus (BV; ) is a zoonotic alphaherpesvirus endemic in macaques that can cause severe, often fatal encephalomyelitis in humans. However, genomic data from wild macaque populations remain limited. Here, we report the isolation and genomic characterization of a BV strain from a wild long-tailed macaque ( ) in Thailand and assess its zoonotic potential. Among 138 macaques screened across six populations, BV shedding was detected in a single oral swab (0.72%). The virus (BV/Thailand/Ranong_TPK5/2024) was successfully isolated and propagated in Vero and LLC-MK2 cells, with higher replication efficiency observed in Vero cells. The TPK5 isolate exhibited a high infectious titre (8 × 10⁷ PFU/mL), and transmission electron microscopy confirmed typical herpesvirus morphology. Whole-genome sequencing achieved deep coverage (∼20,974×) and revealed 98.4% identity to a reference strain (E90-136) from captive long-tailed macaques. Phylogenetic analyses of 12 envelope glycoproteins demonstrated host-associated clustering, with the TPK5 isolate grouping within the long-tailed macaque lineage. Key entry glycoproteins (gB, gD, gH, and gL) were highly conserved among macaques but diverged from human herpes simplex viruses. In contrast, host receptors nectin-1 and nectin-2 were highly conserved between macaques and humans (≥95% identity), suggesting preserved receptor compatibility. Despite the low prevalence of shedding, the isolation of an infectious BV strain from an asymptomatic macaque highlights an ongoing zoonotic risk. Conservation of viral entry mechanisms and host receptors supports the potential for cross-species transmission in high human-macaque interface settings.

Herpes B virus (BV) is a zoonotic virus which can be transmitted from macaques to humans, which is often associated with high mortality rates. Because macaques often exhibit asymptomatic infections, individuals who come into contact with these animals face unexpected risks of BV infections. A serological test is widely performed to investigate BV infections. However, the assay’s sensitivity and specificity appeared to be inadequate, and it does not necessarily indicate ongoing viral shedding. Here, we developed LAMP and qPCR assays aiming to detect BVs with a high sensitivity and specificity in various macaque species and validated them using oral swab samples collected from 97 wild cynomolgus macaques living in Thailand. Our LAMP and qPCR assays detected more than 50 and 10 copies of the target sequences per reaction, respectively. The LAMP assay could detect BV within 25 min, indicating its advantages for the rapid detection of BV. Collectively, our findings indicated that both assays developed in this study exhibit advantages and usefulness for BV surveillance and the diagnosis of BV infections in macaques. Furthermore, for the first time, we determined the partial genome sequences of BVs detected in cynomolgus macaques in Thailand. Phylogenetic analysis revealed the species-specific evolution of BV within macaques.