Pre-existing immunity to heartland virus protects rhesus macaques from challenge with severe fever with thrombocytopenia syndrome virus

Although the animals seroconverted, clinical disease was not observed, suggesting rhesus macaques are unsuitable disease models for HRTV. Lastly, we subsequently tested whether immune responses raised against HRTV could cross-protect against SFTSV challenge and found that prior infection with HRTV limited SFTSV replication and signs of disease. Together, our data establishes a rhesus macaque model of SFTSV infection using a Japanese isolate of SFTSV and demonstrates that pre-existing immunity to HRTV can protect against infection with SFTSV.</p>