A local outbreak of dengue caused by an imported case in Dongguan China

Abstract

BackgroundDengue, a mosquito-borne febrile viral disease, is found in tropical and sub-tropical regions around the world. Since the first occurrence of dengue was confirmed in Guangdong, China in 1978, dengue outbreaks have been reported sequentially in different provinces in South China transmitted by.peridomestic Ae. albopictus mosquitoes, diplaying Ae. aegypti, a fully domestic vector that transmits dengue worldwide. Rapid and uncontrolled urbanization is a characteristic change in developing countries, which impacts greatly on vector habitat, human lifestyle and transmission dynamics on dengue epidemics. In September 2010, an outbreak of dengue was detected in Dongguan, a city in Guangdong province characterized by its fast urbanization. An investigation was initiated to identify the cause, to describe the epidemical characteristics of the outbreak, and to implement control measures to stop the outbreak. This is the first report of dengue outbreak in Dongguan, even though dengue cases were documented before in this city.MethodsEpidemiological data were obtained from local Center of Disease Control and prevention (CDC). Laboratory tests such as real-time Reverse Transcription Polymerase Chain Reaction (RT-PCR), the virus cDNA sequencing, and Enzyme-Linked immunosorbent assay (ELISA) were employed to identify the virus infection and molecular phylogenetic analysis was performed with MEGA5. The febrile cases were reported every day by the fever surveillance system. Vector control measures including insecticidal fogging and elimination of habitats of Ae. albopictus were used to control the dengue outbreak.ResultsThe epidemiological studies results showed that this dengue outbreak was initiated by an imported case from Southeast Asia. The outbreak was characterized by 31 cases reported with an attack rate of 50.63 out of a population of 100,000. Ae. albopictus was the only vector species responsible for the outbreak. The virus cDNA sequencing analysis showed that the virus responsible for the outbreak was Dengue Virus serotype-1 (DENV-1).ConclusionsSeveral characterized points of urbanization contributed to this outbreak of dengue in Dongguan: the residents are highly concentrated; the residents' life habits helped to form the habitats of Ae. albopictus and contributed to the high Breteau Index; the self-constructed houses lacks of mosquito prevention facilities. This report has reaffirmed the importance of a surveillance system for infectious diseases control and aroused the awareness of an imported case causing the epidemic of an infectious disease in urbanized region.

Containment measures for emerging and re-emerging vector-borne and other infectious diseases of poverty in urban settings: a scoping review

“…Community-based measures focused mainly on: involvement and training of community volunteers [33, 35, 36, 38, 49] ( n =  5, 16%); awareness campaigns [20, 30, 31, 40, 41] ( n =  5, 16%); and public education [31, 33, 41, 49] ( n =  4, 13%). They also included community-based surveillance or case-finding [30, 35, 36] ( n =  3, 10%) and social mobilization [22, 36] ( n =  2, 6%).…”

“…The reasons included: high population density [20, 23, 24, 32, 39, 47]; population mobility [30, 32, 35]; and rapid, unplanned urbanization [31, 32]. One article mentioned the lack of community involvement and absence of strong social networks as challenges related to infectious disease control in urban settings.…”

Population genetic structure of Aedes albopictus in Penang, Malaysia

“…A. albopictus was found in the Americas in 1985 and is currently present in 8 American countries (Pinheiro and Nelson, 1997). In China, Peng et al (2012) reported the re-emergence of dengue in a city in southern China 2 decades after a traveler from Southeast Asia introduced A. albopictus. Thus, examining the population genetic structure is important for understanding the evolution of this species (Hewitt, 1983), which may lead to novel methods of controlling disease transmission (Ayres et al, 2003).…”

Molecular characterization and phylogenetic analysis of dengue virus type 1 in Guangdong in 2014

“…Alanine aminotransferase (ALT) levels reached 114 U L −1 , which is approximately three times higher than the upper limit of normal; aspartate aminotransferase (AST) reached 152 U L −1 , which was more than four times higher than the highest normal level; and serum albumin was slightly decreased at 32 g L −1 . The DG14 strain, which was the strain most closely related to GZ02 from Guangdong, was not associated with liver damage (Peng et al 2012). Replication kinetics of DG14, DENV-1 Hawaii (the standard strain), and GZ02 strains were compared in human normal liver cells L02.…”

“…According to epidemiological data, strains from countries that had introduced DENV into Guangdong in the past few years were chosen for genetic analysis (Sang et al 2015; Peng et al 2012). Based on the percent nucleotide and amino acid identities to GZ02, one DENV-1 strain from each of these countries was chosen for phylogenetic analysis of the complete genome (Fig.…”