Severe dengue epidemics in Sri Lanka, 2003-2006

Recent emergence of dengue hemorrhagic fever in the Indian subcontinent has been well documented in Sri Lanka. We compare recent (2003-2006) and past (1980-1997) dengue surveillance data for Sri Lanka. The 4 dengue virus (DENV) serotypes have been cocirculating in Sri Lanka for >30 years. Over this period, a new genotype of DENV-1 has replaced an old genotype. Moreover, new clades of DENV-3 genotype III viruses have replaced older clades. Emergence of new clades of DENV-3 in 1989 and 2000 coincided with abrupt increases in the number of reported dengue cases, implicating this serotype in severe epidemics. In 1980-1997, most reported dengue cases were in children. Recent epidemics have been characterized by many cases in children and adults. Changes in local transmission dynamics and genetic changes in DENV-3 are likely increasing emergence of severe dengue epidemics in Sri Lanka

Infection with chikungunya virus confers heterotypic cross-neutralizing antibodies and memory B-cells against other arthritogenic alphaviruses predominantly through the B domain of the E2 glycoprotein

Infections with Chikungunya virus, a mosquito-borne alphavirus, cause an acute febrile syndrome often followed by chronic arthritis that persists for months to years post-infection. Neutralizing antibodies are the primary immune correlate of protection elicited by infection, and the major goal of vaccinations in development. Using convalescent blood samples collected from both endemic and non-endemic human subjects at multiple timepoints following suspected or confirmed chikungunya infection, we identified antibodies with broad neutralizing properties against other alphaviruses within the Semliki Forest complex. Cross-neutralization generally did not extend to the Venezuelan Equine Encephalitis virus (VEEV) complex, although some subjects had low levels of VEEV-neutralizing antibodies. This suggests that broadly neutralizing antibodies elicited following natural infection are largely complex restricted. In addition to serology, we also performed memory B-cell analysis, finding chikungunya-specific memory B-cells in all subjects in this study as remotely as 24 years post-infection. We functionally assessed the ability of memory B-cell derived antibodies to bind to chikungunya virus, and related Mayaro virus, as well as the highly conserved B domain of the E2 glycoprotein thought to contribute to cross-reactivity between related Old-World alphaviruses. To specifically assess the role of the E2 B domain in cross-neutralization, we depleted Mayaro and Chikungunya virus E2 B domain specific antibodies from convalescent sera, finding E2B depletion significantly decreases Mayaro virus specific cross-neutralizing antibody titers with no significant effect on chikungunya virus neutralization, indicating that the E2 B domain is a key target of cross-neutralizing and potentially cross-protective neutralizing antibodies

Sward evaluation of eleven 'Stylosanthes seabrana' accessions and S. scabra cv. Seca at five subtropical sites

Sown pasture development in the light-textured soils of the seasonally dry tropics and subtropics is based mainly on Stylosanthes species. S. scabra cv. Seca, the cultivar most widely sown, has poor long-term persistence and yield in lower-rainfall subtropical environments experiencing frosts and drought, particularly on clay soils. This study has identified accessions of "Stylosanthes seabrana" which perform well on clay soils in the subtropics, greatly extending the contribution that Stylosanthes species can make to beef production in northern Australia. Although there was abnormally low rainfall during the first 2 years of the experiment, the stylos established and survived in all environments. Most "Stylosanthes seabrana" accessions were consistently superior to Seca in seedling and perennial plant density and yield at most sites, particularly in the third year of the experiment. Seca performed poorly in all attributes in all years with the lowest rank over all years indicating its lack of adaptation. The accessions 92838B and 110361 were selected and released as cultivars Primar and Unica, respectively, in 1996. Primar appears better adapted to the more southerly subtropical sites with early frosts and a short growing season. Unica appears superior to Primar in central Queensland which normally has a longer summer growing season

Clinical features of hospitalized dengue patients in Sri Lanka from 2004 to 2006

The recent emergence of dengue hemorrhagic fever (DHF) in Sri Lanka has been well documented. Here, we present the results of clinical and laboratory evaluation of adult and pediatric PCR positive dengue patients who were hospitalized in Sri Lanka during 2004-2006.  Three hundred and fifty seven patients were included in the study.  Sixty five patients were pediatric (aged 0-12) and 292 patients were adult (aged 13-80).  Patients were classified as having dengue fever (DF), dengue fever with hemorrhagic signs (DFHem) and dengue hemorrhagic fever (DHF). Clinical manifestation of disease differed qualitatively between children and adults. Vomiting and flushing were most common in children and arthralgia/myalgia were the most common finding in adults.  Thrombocytopenia was more common in adults than in children.  A subgroup of 185 patients had the infecting serotype identified by PCR. In the pediatric group, three serotypes, DENV2, DENV3, and DENV4 were found.    DENV3 was the most common overall and in all pediatric diagnoses.  DENV3 and DENV2 were encountered in pediatric DHF patients but not out of proportion to their representation in all pediatric patients.   All four serotypes were identified in the adult group, with DENV3 and DENV2 being the most common.  All four serotypes were found in DHF patients, with DENV3 occurring most frequently but not out of proportion to its occurrence in all adult patients. Our findings, combined with other recent reports of DENV in Sri Lanka, should help us better understand the evolving picture of dengue disease in Sri Lanka.DOI: http://dx.doi.org/10.4038/sljid.v2i1.3004Sri Lankan Journal of Infectious Diseases Vol.2(1) 2012: 9-18</p

Emergence potential of sylvatic dengue virus type 4 in the urban transmission cycle is restrained by vaccination and homotypic immunity

10.1016/j.virol.2013.01.018Virology439134-41VIRL

Features of acute COVID-19 associated with post-acute sequelae of SARS-CoV-2 phenotypes: results from the IMPACC study

Post-acute sequelae of SARS-CoV-2 (PASC) is a significant public health concern. We describe Patient Reported Outcomes (PROs) on 590 participants prospectively assessed from hospital admission for COVID-19 through one year after discharge. Modeling identified 4 PRO clusters based on reported deficits (minimal, physical, mental/cognitive, and multidomain), supporting heterogenous clinical presentations in PASC, with sub-phenotypes associated with female sex and distinctive comorbidities. During the acute phase of disease, a higher respiratory SARS-CoV-2 viral burden and lower Receptor Binding Domain and Spike antibody titers were associated with both the physical predominant and the multidomain deficit clusters. A lower frequency of circulating B lymphocytes by mass cytometry (CyTOF) was observed in the multidomain deficit cluster. Circulating fibroblast growth factor 21 (FGF21) was significantly elevated in the mental/cognitive predominant and the multidomain clusters. Future efforts to link PASC to acute anti-viral host responses may help to better target treatment and prevention of PASC. © 2024, The Author(s).Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]