BackgroundAn earthquake in the coffee growing region of Colombia on January 25, 1999 destroyed 70% of the houses in Armenia city. Transitory housing camps still remained until two years after the disaster. Parasitological studies found that, in this population, giardiasis was the most frequent parasitic infection. This study was carried out in order to determine the epidemiological risk factors associated with this high prevalence.MethodsFecal samples were obtained from 217 children aged between 3 and 13 years. Stool samples were studied by direct wet examination and stained with ferric hematoxilin for microscopical examination. Epidemiological data were collected by questionnaire and analyzed by using the Epi-info software (CDC, Atlanta 2001).ResultsGiardia cysts were observed in 60.4% of the samples presented and trophozoites in 4.6%. The following epidemiological and laboratory factors were significantly associated with Giardia infection: 1. Use of communal toilet (vs. individual toilet) OR: 3.9, CI95%: 1.2–16; 2. water provision by municipal ducts (vs. water provision by individual tanks) OR: 3.5, CI95% 1.1–14, and 3. presence of mucus in stool OR: 2.3, IC95%: 0.9–6.7.ConclusionsA high prevalence of giardiasis was found in children living in temporary houses after the 1999 earthquake in Armenia (Colombia). Giardiasis is an emerging disease in post-disaster situations and adequate prevention measures should be implemented during these circumstances.

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Dung beetles are exposed to a complex microbiological ecosystem during their life cycle. Characterization of novel host-defense peptides (HDP) is essential to understanding the host innate immune response in insects. It constitutes a promising alternative to look for new therapeutic agents against pathogenic microbes. We identified four new HDP, Oxysterlins 1, 2, 3, and 4 from the transcriptome of the Oxysternon conspicillatum dung beetle. These HDP display a highly conserved signal peptide and a mature peptide, characterized by an overall positive charge (cationic) (pI: 10.23–11.49), a hydrophobic ratio (ΦH: 35–41), and amphipathicity. Oxysterlins 1, 2, and 3 have a linear α-helix structure, whilst Oxysterlin 4 has a mixture of both α-helix and β-sheet structures without disulfide bonds through bioinformatics prediction and circular dichroism. Oxysterlins are part of the cecropin family group in an exclusive clade related to beetle cecropins. They have predominant antimicrobial activity against Gram-negative bacteria, including multidrug resistant strains (3.12–50 μg/mL) measured by plate microdilution. Their kinetics, in a time-killing curve showed concentration-dependent bactericidal activity. Furthermore, these HDP have low toxicity against human erythrocytes (62.5–500 μg/mL) and Vero cells (250–500 μg/mL). This article describes new HDP of the cecropin family from the Oxysternon conspicillatum dung beetle, with antimicrobial activity against multidrug resistant bacteria and low toxicity.

Dengue virus (DENV) is a member of the Flaviviridae family, which is transmitted to mammalian species through arthropods, and causes dengue fever or severe dengue fever in humans. The DENV genome encodes for multiple nonstructural (NS) proteins including NS1. NS1 plays an essential role in replication by interacting with other viral proteins including NS4B, however how these interactions are regulated during virus infection is not known. By using bioinformatics, mass spectrometry analysis, and co-immunoprecipitation assays, here we show that DENV-NS1 is ubiquitinated on multiples lysine residues during DENV infection, including K189, a lysine residue previously shown to be important for efficient DENV replication. Data from in vitro and cell culture experiments indicate that dengue NS1 undergoes modification with K48-linked polyubiquitin chains, which usually target proteins to the proteasome for degradation. Furthermore, ubiquitinated NS1 was detected in lysates as well as in supernatants of human and mosquito infected cells. Ubiquitin deconjugation of NS1 using the deubiquitinase OTU resulted in increased interaction with the viral protein NS4B suggesting that ubiquitinated NS1 has reduced affinity for NS4B. In support of these data, a K189R mutation on NS1, which abrogates ubiquitination on amino acid residue 189 of NS1, also increased NS1-NS4B interactions. Our work describes a new mechanism of regulation of NS1-NS4B interactions and suggests that ubiquitination of NS1 may affect DENV replication.