In recent household contacts of persons with HCPS in Chile, the risk of HCPS was greatest among sex partners. Among the household contacts who developed HCPS, viremia preceded the onset of symptoms and the appearance of anti-hantavirus antibodies by up to 2 weeks.

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NCT00128180.

In man, infection with South American Andes virus (ANDV) causes hantavirus cardiopulmonary syndrome (HCPS). HCPS due to ANDV is endemic in Southern Chile and much of Argentina and increasing numbers of cases are reported all over South America. A case-fatality rate of about 36% together with the absence of successful antiviral therapies urge the development of a vaccine. Although T-cell responses were shown to be critically involved in immunity to hantaviruses in mouse models, no data are available on the magnitude, specificity and longevity of ANDV-specific memory T-cell responses in patients. Using sets of overlapping peptides in IFN-γ ELISPOT assays, we herein show in 78 Chilean convalescent patients that Gn-derived epitopes were immunodominant as compared to those from the N- and Gc-proteins. Furthermore, while the relative contribution of the N-specific response significantly declined over time, Gn-specific responses remained readily detectable ex vivo up to 13 years after the acute infection. Tetramer analysis further showed that up to 16.8% of all circulating CD3+CD8+ T cells were specific for the single HLA-B*3501-restricted epitope Gn465–473 years after the acute infection. Remarkably, Gn465–473–specific cells readily secreted IFN-γ, granzyme B and TNF-α but not IL-2 upon stimulation and showed a ‘revertant’ CD45RA+CD27−CD28−CCR7−CD127− effector memory phenotype, thereby resembling a phenotype seen in other latent virus infections. Most intriguingly, titers of neutralizing antibodies increased over time in 10/17 individuals months to years after the acute infection and independently of whether they were residents of endemic areas or not. Thus, our data suggest intrinsic, latent antigenic stimulation of Gn-specific T-cells. However, it remains a major task for future studies to proof this hypothesis by determination of viral antigen in convalescent patients. Furthermore, it remains to be seen whether Gn-specific T cells are critical for viral control and protective immunity. If so, Gn-derived immunodominant epitopes could be of high value for future ANDV vaccines.

The potential incubation period from exposure to onset of symptoms was 7–39 days (median 18 days) in 20 patients with a defined period of exposure to Andes virus in a high-risk area. This period was 14–32 days (median 18 days) in 11 patients with exposure for <48 hours.

The main factors affecting the diversity of arbuscular mycorrhizal fungi (AMF) are host plant, environmental characteristics and geographical location. A better understanding of the influence of land use changes on AMF abundance will help in improving their management, leading to improved plant productivity in soils, and will also be useful in designing more sustainable agronomic management practices. The aim of this work was to document the occurrence and diversity of AMF species in the Southern Central zone of Chile. This information has been generated by seven separate studies which provide the basis for discussion of the AMF species found in this zone. The work includes a bibliographic review of the records from croplands, grasslands and forests generated by collections made during the period 2004-2014 in Chile. Overall we recorded 21 genera and 66 species of Glomeromycota. This represents 24% of species of AMF known so far. Acaulospora represents 23% of all species and Glomus 20%. It is concluded that more studies are needed in this and other regions of Chile for a more comprehensive knowledge of the AMF diversity in the country. These biodiversity studies will help to define the ecology of these important soil microbiological resources.

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