Bulletin of the World Health Organization
-
Bull. World Health Organ. · Jan 1973
The 1970 yellow fever epidemic in Okwoga District Benue Plateau State, Nigeria. 2. Immunity survey to determine geographic limits and origins of the epidemic.
Serological surveys undertaken to define the geographic limits of the 1970 rural yellow fever epidemic in Okwoga District, Nigeria, indicated that surrounding areas of Benue Plateau State and East Central State were not involved. However, the surveys uncovered a separate focus of unrecognized, recent epidemic yellow fever in Mbawsi, in southern East Central State. The highest proportions of yellow-fever-immune sera outside the Okwoga and Mbawsi foci were found in zones of Guinea savannah in the Benue River basin.
-
Bull. World Health Organ. · Jan 1973
Arbovirus studies in Luanda, Angola. 1. Virological and serological studies during a yellow fever epidemic.
A yellow fever epidemic broke out in Luanda, Angola, in January 1971 and was halted in less than 3 months by prompt mass vaccination and intensive antimosquito measures. Nine strains of yellow fever virus were isolated from hospitalized cases, but attempts to isolate the virus from Aedes aegypti mosquitos failed. A serological survey for antibodies to arboviruses in 589 sera from unvaccinated persons showed that two arboviruses were circulating in the epidemic area: the yellow fever virus and the Chikungunya virus responsible for an outbreak of dengue-like disease that occurred shortly before the yellow fever epidemic.
-
Bull. World Health Organ. · Jan 1973
The 1970 yellow fever epidemic in Okwoga District, Benue Plateau State, Nigeria. I. Epidemiological observations.
A focal epidemic of yellow fever occurred in late 1970 in southern Benue Plateau State, Nigeria, 1 year after a much larger outbreak in northern Nigeria. Like its predecessor, the 1970 epidemic was associated with virus transmission by wild-breeding Stegomyia mosquitos. Epidemiological data on the outbreak are reported in this paper.
-
Bull. World Health Organ. · Jan 1973
The 1970 yellow fever epidemic in Okwoga District, Benue Plateau State, Nigeria. 3. Serological responses in persons with and without pre-existing heterologous group B immunity.
Serological studies of persons infected with yellow fever (YF) during the 1970 epidemic in Okwoga District, Nigeria, indicated that epidemic YF occurred despite a high prevalence of pre-existing group B arbovirus immunity, which increased with age. The viruses involved were primarily dengue, Zika, and Wesselsbron. Patterns of responses of haemagglutination-inhibiting, complement-fixing, and neutralizing antibodies in primary YF and in superinfections are defined in this paper.
-
Bull. World Health Organ. · Jan 1973
Arbovirus studies in Luanda, Angola. 2. Virological and serological studies during an outbreak of dengue-like disease caused by the Chikungunya virus.
An outbreak of dengue-like disease was observed in Luanda, Angola, at the end of 1970 and beginning of 1971. Chikungunya virus was isolated from the blood of a patient with typical symptoms of dengue and from a pool of Aedes aegypti mosquitos. A survey for antibodies to arboviruses in the sera of persons living in Luanda showed that the Chikungunya virus was indeed responsible for the outbreak. The fact that this outbreak immediately preceded and continued concurrently with a yellow fever epidemic in Luanda shows that two arboviruses from different antigenic groups may circulate simultaneously in the same ecological area.