Monitoring of dengue viruses in field-caught Aedes aegypti and Aedes albopictus mosquitoes by a type-specific polymerase chain reaction and cycle sequencing.

Abstract

Virologic surveillance for dengue through the detection of the prevalent serotype(s) circulating in the human population during inter-and intra-epidemic periods constitutes a reliable sentinel system for dengue outbreaks. We have applied a rapid and sensitive, semi-nested, reverse transcription-polymerase chain reaction (RT-PCR) assay using nonstructural protein 3 gene primers for the type-specific-detection of dengue viruses in artificially infected and in field-caught adult Aedes mosquitoes. In laboratory experiments, the assay was sensitive enough to detect one virusinfected mosquito head in pools of up to 59 uninfected heads. In a prospective field study conducted from April 1995 to July 1996, female adult Ae. aegypti and Ae. albopictus mosquitoes were caught from selected dengue-sensitive areas in Singapore and assayed by RT-PCR. Approximately 20% of 309 mosquito pools were positive for dengue viruses. Of the 23 RT-PCR-positive Ae. aegypti pools (containing 1-17 mosquitoes each), 18 pools (78.3 %) were positive for dengue 1 virus. There were 40 RT-PCR-positive Ae. albopictus pools (containing 1-33 mosquitoes each) of which 31 (77.5%) were positive for dengue 1 virus. The predominant virus type responsible for the current dengue epidemic since 1995 was also dengue 1. The geographic locations of the virus-infected mosquitoes correlated with the residences or workplaces of patients within dengue outbreak areas. A total of 43.5% of the positive Ae. aegypti pools and 25.0% of the positive Ae. albopictus pools contained only a single mosquito. Both Aedes species showed similar overall minimum infection rates of 57.6 and 50 per 1,000 mosquitoes. Infected Ae. aegypti were detected as early as six weeks before the start of the dengue outbreaks in 1995 and 1996. However, infected Ae. albopictus appeared later, when the number of cases was increasing. Virologic surveillance by RT-PCR for detecting dengue virus-infected Aedes mosquitoes in the field may serve as an early warning monitoring system for dengue outbreaks.

Dengue virus type 4 in Niterói, Rio de Janeiro: the role of molecular techniques in laboratory diagnosis and entomological surveillance

“…Likewise, DENV-1 was also detected during a DENV-4 surveillance study in RR in 2010 (MG de Castro et al, unpublished observations). It has been suggested that a predominant serotype may persist for one or two years until it is replaced by a new serotype (Chow et al 1998). In the present study, infection with DENV-4 in humans and mosquitoes was confirmed during an explosive DENV-1 epidemic in RJ, as well as in other Brazilian states.…”

“…The entomological surveillance of DENV in adult and immature mosquito stages is an important tool for the early prediction of dengue epidemics. Additionally, the virological surveillance of field-caught dengue vectors using molecular techniques, such as conventional reverse transcriptase-polymerase chain reaction (RT-PCR), has been useful for the rapid detection of dengue outbreaks in endemic regions and/or for the detection of the introduction of novel DENV variants (Chow et al 1998, Pinheiro et al 2005, Mendez et al 2006, Chen et al 2010, Guedes et al 2010.…”

Evaluation of the Dengue NS1 Ag Strip®for Detection of Dengue Virus Antigen inAedes aegypti(Diptera: Culicidae)

“…includes isolation and propagation of viruses, reverse transcriptasepolymerase chain reaction (RT-PCR) assays, or enzymelinked immunosorbent assay or immunofluorescence assay (Kuberski et al 1977, Chan et al 1994, Sithiprasasna et al 1994, Rohani et al 1997, Chow et al 1998, Samuel and Tiyagi 2006. However, the need for expensive specialized laboratories and equipment and highly trained staff has made these techniques impractical for regular surveillance of DENVinfected mosquitoes.…”

Detection of dengue virus serotype 3 by reverse transcription-polymerase chain reaction in Aedes aegypti (Diptera, Culicidae) captured in Manaus, Amazonas

“…The RT-PCR technique for detecting dengue virus in mosquito tissues has been performed in several regions of the world since the 1990s (Chungue et al 1993, Chow et al 1998, Harris et al 1998, Romero-Vivas et al 2000, Kow et al 2001, Chung & Pang 2002, Urdaneta et al 2005. Mostly of these studies were conducted in Asia, where the four serotypes occur and the incidence of DHF/DSS is very high.…”