Pathogenicity and immunogenicity of a mutagen-attenuated Rift Valley fever virus immunogen in pregnant ewes

• Published in: American journal of veterinary research Vol. 48; no. 7; p. 1042
• Main Authors: Morrill, J.C, Jennings, G.B, Caplen, H, Turell, M.J, Johnson, A, Peters, C.J
• Format: Journal Article
• Language: English
• Published: United States 01.07.1987
• Subjects: Animals; ANTIBODIES; Antibodies, Viral - analysis; ANTICO036; ANTICUERPOS; ATTENUATION; BREBIS; Bunyaviridae - pathogenicity; CULEX; CULEX PIPIENS; EWES; Female; GESTACION; GESTATION; IMMUNE RESPONSE; MUTAGENE; MUTAGENOS; MUTAGENS; OVEJA; PATHOGENICITY; PODER PATOGENO; POUVOIR PATHOGENE; PREGNANCY; Pregnancy Complications, Infectious - prevention & control; Pregnancy Complications, Infectious - veterinary; Pregnancy, Animal - immunology; REPONSE IMMUNITAIRE; RESPUESTA INMUNOLOGICA; Rift Valley Fever - prevention & control; RIFT VALLEY FEVER VIRUS; Rift Valley fever virus - immunology; Rift Valley fever virus - pathogenicity; Sheep; Sheep Diseases - immunology; Sheep Diseases - microbiology; Viral Vaccines - immunology; VIRUS FIEBRE DEL VALLE DEL RIFT; VIRUS FIEVRE DE LA VALLEE DU RIFT
• ISSN: 0002-9645; 1943-5681

A mutagenized clone of Rift Valley fever virus (RVFV; MV P12) used in inoculation of 3 pregnant ewes was immunogenic, nonpathogenic, and nonabortogenic. In contrast, inoculation of a matched group of 3 pregnant ewes with parent RVFV induced clinical disease and abortions. Ewes given MV P12 delivered healthy lambs that had RVFV antibody titers of less than 1:10 at birth, increasing to greater than or equal to 1:80 after ingestion of colostrum. Ewes inoculated with parent RVFV developed marked viremia, followed by RVFV antibody titers greater than or equal to 1:1,280; ewes inoculated with MV P12 developed low viremia titers and RVFV antibody titers of 1:80 to 1:320. Postpartum challenge exposure of the previously MV P12-inoculated ewes with virulent Zagazig human 501 strain RVFV indicated that the ewes were protected from clinical disease. The RVFV-susceptible female Culex pipiens that fed on the MV P12-inoculated ewes failed to transmit RVFV to hamsters; mosquitoes that fed on the parent RVFV-inoculated ewes became infected and transmitted RVFV to hamsters.