Evaluation of the immune response of Rift Valley Fever vaccination in sheep and goats using PCR and ELISA techniques

Abstract

This study was carried out in Jazan, Saudi Arabia for Evaluation of the immune response of Rift Valley Fever Vaccination in sheep and goats using PCR and ELISA techniques. 30 sheep (20 vaccinated and 10 control) and 30 goats (20 vaccinated and 10 controls) were used in this study. This study was done to evaluate the immune response of RVF smith-burn vaccine in sheep and goats in Jazan region South of Saudi Arabia using ELISA and PCR techniques. The results of direct ELISA for virus detection in all examined animals showed that out of the examined 40 vaccinated animals, no virus was detected at one and 3 days post vaccination whereas at 6, 10 and 14 days post vaccination the virus was detected in 12 (30%), 20 (50%) and 34 (85%) animals. Moreover, no virus was detected after 6 months post vaccination. In addition, no virus was detected in control non vaccinated animals. Concerning sheep, the results of direct ELISA for virus detection showed that out of the examined 20 vaccinated sheep, no virus was detected at one and 3 days post vaccination whereas, 6, 10 and 14 days post vaccination the virus was detected in 7 (35%), 11 (55%) and 18 (90%) sheep. Moreover, no virus was detected after 6 months post vaccination. In addition, no virus was detected in control non vaccinated sheep. Concerning goats, the results of direct ELISA for virus detection showed that out of the examined 20 vaccinated goats, no virus was detected at one and 3 days post vaccination, whereas at 6, 10 and 14 days post vaccination the virus was detected in 5 (25%), 9 (45%) and 16 (80%) goats. Moreover, no virus was detected after 6 months post vaccination. In addition, no virus was detected in control non vaccinated goats. The results of direct ELISA for virus detection in the liver tissues at six months post vaccination revealed no virus in both vaccinated sheep and goats. The results of indirect ELISA, proved that out of the vaccinated 40 animals (20 sheep and 20 goats), 12 (30%) animals have IgM and 8 (20%) have IgG at the third week post vaccination, 4 (10%) animals have IgM and 20 (50%) have IgG at the fourth week post vaccination, 5 (12.5%) animals have IgM and 32 (80%) have IgG at the fifth week post vaccination , 0 (0%) animals have IgM and 33 (82.5%) have IgG at the six week post vaccination, 0 (0%) animals have IgM and 35 (87.5%) have IgG at the seven week post vaccination. In contrast, neither IgM nor IgG were detected in the control groups. Concerning sheep, the results of indirect ELISA, proved that out of the vaccinated 20 sheep (35%) animals have IgM and 4 (20%) have IgG at the third week post vaccination, 3 (15%) animals have IgM and 9 (45%) have IgG at the fourth week post vaccination, 3 (15%) animals have IgM and 17 (85%) have IgG at the fifth week post vaccination , 0 (0%) animals have IgM and 18 (90%) have IgG at the six week post vaccination, 0 (0%) animals have IgM and 18 (90%) have IgG at the seven week post vaccination. In contrast, neither IgM nor IgG were detected in the control groups. Concerning goats, the results of indirect ELISA, proved that out of the vaccinated 20 goats 5 (25%) animals have IgM and 4 (20%) have IgG at the third week post vaccination, 1 (5%) animals have IgM and 11 (55%) have IgG at the fourth week post vaccination, 2 (10%) animals have IgM and 15 (75%) have IgG at the fifth week post vaccination, 0 (0%) animals have IgM and 15 (75%) have IgG at the six week post vaccination, 0 (0%) animals have IgM and 17 (85%) have IgG at the seven week post vaccination. In contrast, neither IgM nor IgG were detected in the control groups. The results of PCR for virus detection showed that out of the examined 40 vaccinated animals, no virus was detected at one day post vaccination whereas, at 3, 6, 10 and 14 days post vaccination the virus was detected in 1 (2.5%), 8 (20%), 11 (27.5%) and 21 (52.5%) animals respectively. Moreover, no virus was detected after 6 months post vaccination. In addition, no virus was detected in control non vaccinated animals. Concerning sheep, out of the examined 20 vaccinated sheep, the results of PCR for virus detection showed that no virus was detected at one day post vaccination whereas, at 3, 6, 10 and 14 days post vaccination the virus was detected in 1 (5%), 5 (25%) , 7 (35%) and 12 (60%) sheep respectively. Moreover, no virus was detected after 6 months post vaccination. In addition, no virus was detected in control non vaccinated sheep. Concerning goats, the results of PCR for virus detection showed that out of the examined 20 vaccinated goats, no virus was detected at one and 3 days post vaccination, whereas at 6, 10 and 14 days post vaccination the virus was detected in 3 (15%), 4 (20%) and 9 (45%) goats respectively. Moreover, no virus was detected after 6 months post vaccination. In addition, no virus was detected in control non vaccinated goats. The results of PCR for virus detection in the liver tissues at six months post vaccination revealed no virus in both vaccinated sheep and goats. Histopathological examination of the livers of vaccinated animals at 6 months post vaccination revealed no pathological changes. We concluded lastly that, as a result of the restricted occurrence of the disease in Jazan region, control measures must be taken to prevent further spread of the disease to other Saudi Arabia regions. Also, continuous monitoring and surveillance must be applied concerning RVF in Jazan. Also, direct ELISA and PCR techniques can be used effectively in RVFV detection and indirect ELISA technique can be used effectively in RVF IgM and IgG detection.