Biomedical subjects

B F Eldridge

Publications and source records attributed to B F Eldridge.

50 records · Page 3Linked to original sources

PubMed1975

Ecology of Keystone virus, a transovarially maintained arbovirus.

Our studies in the Pocomoke Cypress Swamp of Maryland have shown that KEY strain of CE is endemic and is carried by the floodwater mosquito A. atlanticus. The virus is transmitted transstadially in nature, as evidenced by our recovery of virus from larvae and males of this species. Serologic evidence, both here and elsewhere, indicates that vertebrates are infected with KEY, but their role in the transmission cycle remains unknown. We have found several animals, for example, the gray squirrel, that are potential vertebrate reservoirs for the virus. Gray squirrels possess antibodies to KEY in nature, are known to be fed upon by A. atlanticus females, and have been shown to circulate a high-titered viremia after experimental inoculation. Evidence from 1974 collections, however, indicates that A. atlanticus females ingested only a single blood meal during the period when adults were active. We will not be able to assess the relative importance of the vertebrate and mosquito cycles until much more work has been performed on vector-reservoir-virus dynamics.

Aedes↗

PubMed1975

Ecology of California encephalitis viruses on the Del Mar Va Peninsula. I. Virus isolations from mosquitoes.

The ecology of California encephalitis viruses was studied on the Del Mar Va Peninsula. Adult mosquitoes were collected weekly from May to October of 1971 and monthly from May to October of 1972, using CDC miniature light traps with Dry Ice. Floodwater mosquitoes were assayed for virus in suckling mice or cell cultures. In 1971 over 77,000 mosquitoes were processed, resulting in 33 virus isolations. In 1972, over 106,000 were processed and 63 virus strains were recovered. Of the 1971 strains, all but one were recovered from Aedes atlanticus mosquitoes, and of the 1972 strains all but two were recovered from A. atlanticus. All A. atlanticus strains were neutralized by Keystone virus mouse hyperimmune ascitic fluid (MHAF). All other strains were recovered from A. canadensis mosquitoes. The single 1971 strain, and one strain from 1972, were neutralized by Jamestown Canyon MHAF. The remaining strain was neutralized by Keystone MHAF. The rate of virus recovery from A. atlanticus remained approximately the same, both between years and during each year studied, even during periods when large numbers of adults were emerging, suggesting that these mosquitoes had emerged infected.

Animals↗

PubMed1975

Ecology of California encephalitis viruses on the Del Mar Va Peninsula. II. Demonstration of transovarial transmission.

The high rate of Keystone virus recovery from Aedes atlanticus collected in 1971 and 1972 suggested that these mosquitoes might be emerging infected. To demonstrate the suspected transovarial transmission of this virus, developmental stages of A. atlanticus were collected from the field. Larvae were identified and pooled for virus isolation in suckling mice. Pupae were allowed to emerge in the laboratory, then were segregated by sex and pooled for virus isolation. Keystone virus was recovered from larvae, reared males and reared females, demonstrating transovarial transmission of the Keystone strain of California encephalitis by A. atlanticus.

Aedes↗

PubMed1975

Transovarial transmission of arboviruses by mosquitoes: a review.

One interesting aspect of mosquito-borne arboviruses is their endemic persistence, espeically during adverse climatic conditions in the temperate zones. The hypothesis that transovarial transmission of alpha- and flaviviruses by their respective mosquito vectors could serve as an overwintering mechanism has been proposed; however, experimental data in support of this hypothesis are not very convincing. Recently, some of the California encephalitis group arboviruses have been shown to be transmitted transovarially by Aedes species mosquitoes, and studies indicate that this mechanism contributes to the natural maintenance cycle of these viruses. Finally, consideration is given to the possibility that transovarial transmission may be unique to the California encephalitis group arboviruses and may be related to their association with a vector that overwinters in the egg stage of its life cycle.

Aedes↗

PubMed1974