Preliminary survey of domestic animals of the Sudan for precipitating antibodies to Rift Valley fever virus

Abstract

SUMMARYIn a preliminary seroepidemiological survey a total of 780 serum samples derived from various domestic animals of the Sudan were examined for Rift Valley fever (RVF) virus precipitating antibodies. The incidence was approximately 34-3 % in sheep, 33-2 % in cattle, 22 % in goats, 7 9 % in camels and 4 % in donkeys. The findings indicated that RVF is mainly prevalent in the rich savanna areas of the south as well as the irrigated areas close to the Nile in the north.Circumstantial evidence suggests that the detected antibodies were induced by a long-standing cryptically cycling infection and that resurgence of extensive epizootics is unlikely although limited outbreaks may occur. It is concluded that RVF virus circulates across the country in a south-north range along the Nile Valley with little or no extension to the drier lands to the east and west, and that ruminants are the primary species involved in virus maintenance. These species evidently serve as main amplifiers of infection during epizootics, but whether or not they also serve as sole virus reservoirs in inter-epizootic periods has yet to be determined.

Rift Valley Fever, Sudan, 2007 and 2010

“…El Gezira and, to a lesser degree, Sennar, White Nile, and Khartoum States, have vast tracts of irrigated land. Khartoum State has a growing agricultural industry along the Blue Nile River, particularly in Hilat Kuku, Khartoum North, which was the focus of the 1977 Sudan RVF outbreak ( 15 ). During the end of November 2007, the El Gezira authorities instituted an extensive insecticide spraying program and the federal government restricted trade of livestock and associated products in the state, which may have contributed to the subsequent decline in suspected cases.…”

“…Serologic surveys have detected RVFV antibodies in domestic livestock ( 14 , 15 ) and in humans from different Sudanese states, including Nile, Khartoum, Kassala, El Gezira, Sennar, and White Nile ( 16 – 18 ). A recent seroepidemiologic survey reported a high prevalence of RVFV IgG among febrile patients admitted to New Halfa Hospital in Kassala State ( 19 ).…”

Molecular and Serological Studies on the Rift Valley Fever Outbreak in Mauritania in 2010

“…Camels played an important role in RVFV epidemics in Kenya (Scott et al., ; Davies et al., ), Nigeria (Davies et al., ), Sudan (Eisa, ), Egypt (Davies et al., ; Ahmed Kamal, ) and Morocco (El‐Harrak et al., ). During the first RVF outbreak in Egypt, camels which were moved from northern Sudan to the southern parts of Egypt may have spread the virus (Ahmed Kamal, ).…”

Phylogeography of Rift Valley Fever Virus in Africa and the Arabian Peninsula

“…This result suggests that, although Zimbabwe was the sampled origin for these lineages, they travelled north over Sudan to Egypt; all available Sudanese sequences came from more recent outbreaks in 2007–2010, which presumably originated in Kenya, and are genetically distant from Egyptian strains in the outbreak of the 1970s [44]. With no earlier Sudanese sequences available [53,54], this analysis could not find an origin in Sudan, and hence tracked lineages back to Zimbabwe; this result should thus not be taken to indicate that the hypothesis of a Sudanese origin for Egyptian epidemics is incorrect.…”