Eastern equine encephalitis in Latin America.

BACKGROUND: The eastern equine encephalitis (EEE) and Venezuelan equine encephalitis (VEE) viruses are pathogens that infect humans and horses in the Americas. Outbreaks of neurologic disease in humans and horses were reported in Panama from May through early August 2010. METHODS: We performed antibody assays and tests to detect viral RNA and isolate the viruses in serum samples from hospitalized patients. Additional cases were identified with enhanced surveillance. RESULTS: A total of 19 patients were hospitalized for encephalitis. Among them, 7 had confirmed EEE, 3 had VEE, and 1 was infected with both viruses; 3 patients died, 1 of whom had confirmed VEE. The clinical findings for patients with EEE included brain lesions, seizures that evolved to status epilepticus, and neurologic sequelae. An additional 99 suspected or probable cases of alphavirus infection were detected during active surveillance. In total, 13 cases were confirmed as EEE, along with 11 cases of VEE and 1 case of dual infection. A total of 50 cases in horses were confirmed as EEE and 8 as VEE; mixed etiologic factors were associated with 11 cases in horses. Phylogenetic analyses of isolates from 2 cases of equine infection with the EEE virus and 1 case of human infection with the VEE virus indicated that the viruses were of enzootic lineages previously identified in Panama rather than new introductions. CONCLUSIONS: Cases of EEE in humans in Latin America may be the result of ecologic changes that increased human contact with enzootic transmission cycles, genetic changes in EEE viral strains that resulted in increased human virulence, or an altered host range. (Funded by the National Institutes of Health and the Secretaría Nacional de Ciencia, Tecnología e Innovación, Panama.).

Molecular Epidemiology of Dengue in Panama: 25 Years of Circulation.

Dengue virus (DENV) is the most prevalent arbovirus in terms of human public health importance globally. In addition to DENV epidemiological surveillance, genomic surveillance may help investigators understand the epidemiological dynamics, geographic distribution, and temporal patterns of DENV circulation. Herein, we aimed to reconstruct the molecular epidemiology and phylogeny of DENV in Panama to connect the epidemiological history of DENV dispersal and circulation in Latin America. We retrospectively analyzed the epidemiological data obtained during 25 years of DENV surveillance in Panama. DENV was reintroduced in Panama in 1993 after a 35 year absence of autochthonous transmission. The increase in the number of total dengue cases has been accompanied by an increase in severe and fatal cases, with the highest case fatality rate recorded in 2011. All four serotypes were detected in Panama, which is characterized by serotype replacement and/or co-circulation of multiple serotypes. Phylogenetic analysis of datasets collected from envelope (E) gene sequences obtained from viruses isolated from human sera demonstrated that circulating viruses were highly diverse and clustered in distinct clades, with co-circulation of clades from the same genotype. Our analyses also suggest that Panamanian strains were related to viruses from different regions of the Americas, suggesting a continuous exchange of viruses within the Americas.

Genetic Characterization of Rubella Virus Strains Detected in Spain, 1998-2014.

The National Plan for the Elimination of Rubella was implemented in Spain in 2008 using the logistics of the National Plan for the Elimination of Measles that have been employed since year 2000. Molecular characterization of rubella virus (RUBV) is important for disease surveillance and for monitoring elimination of the disease throughout the world. We describe the first complete series of data regarding the circulation of RUBV genotypes in Spain. The 739-nucleotide fragment designated by the WHO for RUBV genotyping was sequenced in 88 selected cases collected from 1998 to 2014. Five genotypes were identified: 1E, 2B, 1J, 1I, and 1a. Genotype 1E was predominant between 1998 and 2003 but was replaced by genotype 2B, which was detected in sporadic cases in 2004, 2006, 2008, 2012, 2013 and 2014. There was an outbreak of genotype 2B in Algeciras (Andalusia) in 2008. Genotype 1J caused an outbreak in Madrid in 2004/2005 and sporadic cases in 2005 and 2007. Genotype 1I was found to have infected an immune-suppressed patient with neurological symptoms in 2008. Finally, vaccine strain RA 27/3 was detected in three sporadic cases, two of them immune-suppressed and without a recent history of vaccination. This suggests that during these years there were a series of imported sporadic cases and outbreaks, confirming the findings of epidemiological data analysis. The importation sources were generally consistent with our geographic and cultural ties, mainly with Europe (genotypes 1E, 2B, 1I) and Latin America (1J).

Madariaga virus infection associated with a case of acute disseminated encephalomyelitis.

We present the first report of a pediatric case of acute disseminated encephalomyelitis (ADEM) associated with Madariaga virus infection (MADV, Alphavirus, Togaviridae; formerly known as South American variants of eastern equine encephalitis virus [EEEV]) in a patient of the 2010 alphaviral epidemic reported in Panama. The patient was admitted to the Hospital del Niño in Panama City with suspected meningitis, exhibited with decreased alertness and disorientation in space and time, hemiparesis, and left Babinski sign. The patient was transferred to the intensive care unit and treated with aciclovir and methylprednisolone. The magnetic resonance imaging (MRI) of the brain revealed multiple hyperintense lesions at T2-weighted images (T2) and fluid-attenuated inversion recovery (FLAIR) on the cortical-subcortical level. Sera samples obtained on days 6 and 12 were immunoglobulin M (IgM) positive for MADV. The findings on the clinical and cerebrospinal analyses, rapid symptom progression as well as neuroimaging, and serologic studies support our diagnosis. Our results suggest that MADV should be included in the etiologic differential diagnosis of ADEM in endemic countries.