Arbovirus Circulation, Temporal Distribution, and Abundance of Mosquito Species in Two Carolina Bay Habitats

Abstract

Carolina bays, a type of geomorphic feature, may be important in the ecology of mosquito vectors in South Carolina. Their hydrology varies from wetland habitats with marked flooding/drying regimes to permanently flooded spring-fed lakes. Moreover, they possess characteristics that contribute to the support of a particularly abundant and diverse invertebrate fauna. Although it has been estimated that 2,700+ bays exist in South Carolina, approximately 97% have been altered; < or = 200 bays remain intact, and only 36 are protected by state-funded conservation projects. We conducted a study in two distinct Carolina bay habitats, Savage Bay Heritage Preserve (SBHP) and Woods Bay State Park (WBSP), from June 1997 to July 1998 to determine mosquito temporal distribution, species composition, and the occurrence of arbovirus activity. The largest mosquito collection was obtained at WBSP (n = 31,172) representing 25 species followed by SBHP (n = 3,940) with 24 species. Anopheles crucians complex were the most common species encountered in both bays. Two virus isolates were obtained from SBHP in 1997: Keystone (KEY) virus from Ochlerotatus atlanticus-tormentor and Cache Valley (CV) virus from Oc. canadensis canadensis. Twenty-nine (29) arbovirus-positive pools were obtained from WBSP: 28 in 1997 and one in 1998. KEY virus was isolated from three pools of Oc. atlanticus-tormentor and Tensaw (TEN) virus was isolated from two pools of An. crucians complex; 10 isolates could not be identified with the sera available. Additionally, 14 pools of An. crucians complex tested positive for Eastern equine encephalitis (EEE) virus antigen. These represent the first record of KEY and CV viruses in South Carolina. Our data indicate the presence of high mosquito density and diversity in both Carolina bay habitats, which may be influenced, in part, by seasonal changes in their hydroperiods. The study of mosquito and arbovirus ecology in Carolina Bay habitats could provide more information on the transmission dynamics of arboviruses and its impact on human and animal arboviral disease occurrence in South Carolina.

Host Feeding Patterns of Potential Vectors of Eastern Equine Encephalitis Virus at an Epizootic Focus in Tennessee

“…16,17,42 † Relative number of EEEV-positive pools detected: 0, never isolated; 1, rarely isolated; 2, occasionally isolated; 3, commonly isolated. 6,9,11,18,19,[43][44][45][46] ‡ Distance from forest margin when host seeking: 0, < 1 km; 1, 1-3 km; 2, 3-8 km; 3, > 8 km. 45,[47][48][49][50][51] § Population abundance in CDC light traps at epizootic site during summer of 2006: 0, < 1% of total; 1, 1-10%; 2, 10-20%; 3, > 20% (Mukherjee and others, unpublished data).…”

“…6,9,11,18,19,[43][44][45][46] ‡ Distance from forest margin when host seeking: 0, < 1 km; 1, 1-3 km; 2, 3-8 km; 3, > 8 km. 45,[47][48][49][50][51] § Population abundance in CDC light traps at epizootic site during summer of 2006: 0, < 1% of total; 1, 1-10%; 2, 10-20%; 3, > 20% (Mukherjee and others, unpublished data). ¶ Potential for species to be enzootic or maintenance vector: 0, no potential; 1, minor potential; 2, moderate potential; 3, major potential.…”

Tensaw virus genome sequence and its relation to other Bunyaviridae

“…In the United States, TSV was originally isolated in 1960 from Anopheles crucians mosquitoes in southern Alabama [6]. Surveillance studies have shown that TSV can be found from North Carolina and Texas to Florida [7][8][9]. Although TSV has been most frequently isolated from Anopheles crucians, it has also been found in Anopheles quadrimaculatus, Psorophora confinnis, Aedes atlanticus, Aedes mitchellae, Culex nigripalpus, and Mansonia peturbans [7,9].…”

“…Surveillance studies have shown that TSV can be found from North Carolina and Texas to Florida [7][8][9]. Although TSV has been most frequently isolated from Anopheles crucians, it has also been found in Anopheles quadrimaculatus, Psorophora confinnis, Aedes atlanticus, Aedes mitchellae, Culex nigripalpus, and Mansonia peturbans [7,9]. Serological studies have shown that TSV infects a variety of wild and domestic vertebrates [7][8][9], as well as humans.…”

“…Although TSV has been most frequently isolated from Anopheles crucians, it has also been found in Anopheles quadrimaculatus, Psorophora confinnis, Aedes atlanticus, Aedes mitchellae, Culex nigripalpus, and Mansonia peturbans [7,9]. Serological studies have shown that TSV infects a variety of wild and domestic vertebrates [7][8][9], as well as humans. Serum samples from south Florida residents presented cross-reactivity with either the 1960 virus prototype (A9-171b) or antigenic subtypes (variants) of the Tensaw virus [10].…”