The reintroduction of DENV-2 in 2011 in Panama and subsequent outbreak characteristic

Abstract

The circulation of the South-east Asian/American (AS/AM) dengue 2 virus (DENV-2) genotype in the Americas has been associated with a high rate of severe disease. From 1993, the year DENV was reintroduced in Panama, until 2011 there were 29 dengue-associated deaths, 17 of which occurred in 2011, the most severe outbreak with a case fatality rate (CFR) of 44% (17 deaths out of 38 severe dengue cases). During this outbreak DENV-2 was reintroduced into the country, whereas over the prior five years DENV-1 and −3 were predominant. Herein, we describe the 2011 Panama outbreak and genetically characterize the Panamanian DENV-2 strains, which were associated with severe dengue disease in Panama. Our results suggest that the DENV-2 isolates from this outbreak belonged to the AS/AM genotype sub-clade 2BI and were genetically close to viruses described in the outbreaks in Nicaragua, Honduras, Guatemala and Mexico from 2006–2011. Sub-clade 2BI has previously been associated with severe disease in Nicaragua during outbreaks from 2005–2007.

Molecular Epidemiology of Dengue in Panama: 25 Years of Circulation

“…DENV-2 isolates PA 2010-2015 clustered together with a Puerto Rican strain from 2013 and belonged to the AS/AM genotype sub-clade 2b-I (following [18] classification of Central American strains). They were genetically close to viruses described in Central America and Mexico from 2006–2011, which were also associated with outbreaks [18]; however the PA 2010–2015 and the PR 2013 had a substitution (A50T) in the E protein that might be associated with antibody escape [21]. Since 2012, some strains could be regrouped within another cluster, PA 2012–2017.…”

“…The case fatality rate (CFR) differed between outbreaks: the highest was in 2004 (0.49/100,000 inhabitants), followed by the 2011 outbreak (0.44/100,000 inhabitants.). Further, 2011 was also the year with the most fatal cases (Table 1, Figure 1; [21]).…”

“…During that year, Panama did not show an increase in cases, but reported the detection of DENV-2, with co-circulation of DENV-1 and DENV-3, like Costa Rica. In Panama, this re-emergence of DENV-2 was associated with an important epidemic event one year later [21]. DENV-2 isolates PA 2010-2015 clustered together with a Puerto Rican strain from 2013 and belonged to the AS/AM genotype sub-clade 2b-I (following [18] classification of Central American strains).…”

“…Overlapping sequence segments were assembled and analyzed using Sequencher (version 5.0.1). Of the selected 222 strains, the full E gene was successfully obtained for 179 isolates and deposited in GenBank (93 strains for DENV-1: MH879156–MH879248; 53 for DENV-2: KY977454–KY977459, MF491509, MF491510 [21], and MH824748–MH824794; 26 for DENV-3: MH925274–MH925300; and 7 for DENV-4: MH824741–MH824747).…”

“…There is limited information on the spatiotemporal circulation of various serotypes and genotypes in Panama [19,20]. We previously demonstrated that the DENV-2 strains detected in the 2011 Panama outbreak that were associated with a high case fatality rate [21] were related to strains from outbreaks in Nicaragua and Guatemala in 2009–2010 [22]. In order to determine the effects of co-circulation and the introduction of new DENV serotypes in Panama, we analyzed the dynamics of the strains sampled over a period of 25 years, complemented with an analysis of epidemiological data.…”