African horsesickness virus infection in adult mice

Adult BALB/c mice were inoculated intranasally with African horsesickness virus serotype 4 (AHSV-4), the attenuated-vaccine strain. The 4-week-old mice died after developing nervous signs at 7 to 8 days post infection (p.i). Lesions, such as perivascular accumulation of lymphocytes and necrosis of neurons, were found only in the brains of virus-infected mice, hut not in those of controls. Brains, red blood cells (RBC) and white blood cells (WBC) were collected from two mice each day p.i for virus isolation and RT-PCR. Virus could he isolated from, brains collected at 2 to 7 days p.i of infection mice and only one of WBC sample collected on 7 day p.i, but no virus was isolated from any RBC samples. In contrast, RT-PCR products were visible, in agarose gel electrophoresis stained with ethidium bromide from RBC and WBC samples collected at days 1 to 7 p.i, and from brain samples collected at days 2 to 7 p.i. The amplified PCR products were increased with days p.i when using extracted RNAs from brain samples, but the quantity of the PCR products was relatively constant with the RBC and WBC samples. It was shown that mice were susceptible to AHSV.