When patients present to specialized clinics after travel to the developing world, travel destinations are associated with the probability of the diagnosis of certain diseases. Diagnostic approaches and empiric therapies can be guided by these destination-specific differences.
Diarrhoea remains a significant cause of morbidity and mortality in developing countries where numerous cases remain without identified aetiology. Astroviruses are a recently identified cause of animal gastroenteritis which currently includes two species suspected of causing human diarrhoea. Using pan-astrovirus RT-PCR, we analysed human stool samples from different continents for astrovirus-related RNA sequences. We identified variants of the two known human astrovirus species plus, based on genetic distance criteria, three novel astrovirus species all distantly related to mink and ovine astroviruses, which we provisionally named HMOAstV species A-C. The complete genome of species A displayed all the conserved characteristics of mammalian astroviruses. Each of the now three groups of astroviruses found in human stool (HAstV, AstV-MLB and HMOAstV) were more closely related to animal astroviruses than to each other, indicating that human astroviruses may periodically emerge from zoonotic transmissions. Based on the pathogenic impact of their closest phylogenetic relatives in animals, further investigations of the role of HMOAstV, so far detected in Nigeria, Nepal and Pakistan, in human gastroenteritis are warranted. INTRODUCTIONThe family Astroviridae consists of small (28-30 nm in diameter), non-lipid enveloped, single-stranded positivesense RNA viruses whose genomes range in size from 6.4 to 7.3 kb. The genome includes three open reading frames (ORFs) designated ORF1a, ORF1b and ORF2. ORF1a encodes the non-structural polyprotein 1a while the longer ORF1b encodes polyprotein 1ab including the RNA dependent RNA polymerase (RdRp) expressed through a ribosomal frameshift at the ORF1a/1b junction mediated by a slippery polyA sequence. ORF2 encodes the viral capsid structural polyprotein (Mendéz & Arias, 2007; Monroe et al., 2005).The family Astroviridae consists, so far, of two genera, Avastrovirus and Mamastrovirus, that infect avian and mammalian hosts, respectively. Astroviruses, transmitted through the faecal-oral route can cause gastroenteritis in mammalian and avian species, including humans, calves, piglets, sheep, minks, dogs, cats, mice, chickens and turkeys (Jonassen et al., 2001(Jonassen et al., , 2003. All eight known human astrovirus serotypes belonging to the first identified human astrovirus species (HAstV) have been associated with gastroenteritis (Clark & McKendrick, 2004;Fodha et al., 2006; Gabbay et al., 2007;Jin et al., 2009; Tayeb et al., 2008). Clinical symptoms of HAstV infection in humans usually last between 2 and 4 days and consist of watery diarrhoea and, less commonly, vomiting, headache, fever, abdominal pains and anorexia (Mendéz & Arias, 2007; Monroe et al., 2005). HAstV can also cause significant disease in the elderly and in immunocompromised patients (Liste et al., 2000). Recently, a second species of astrovirus was found in a child with diarrhoea and named AstV-MLB (Finkbeiner et al., 2008).Group-reactive or pan-PCR approaches have been used successfully to identify new viruses ...
A novel picornavirus genome was sequenced, showing 42.6%, 35.2%, and 44.6% of deduced amino acid identities corresponding to the P1, P2, and P3 regions, respectively, of the Aichi virus. Divergent strains of this new virus, which we named salivirus, were detected in 18 stool samples from Nigeria, Tunisia, Nepal, and the United States. A statistical association was seen between virus shedding and unexplained cases of gastroenteritis in Nepal (P ؍ 0.0056). Viruses with approximately 90% nucleotide similarity, named klassevirus, were also recently reported in three cases of unexplained diarrhea from the United States and Australia and in sewage from Spain, reflecting a global distribution and supporting a pathogenic role for this new group of picornaviruses.The falling cost of DNA sequencing has led to a recent surge in human and animal virus discoveries (1-3, 5-12, 14, 16-17, 19-24, 27, 30, 31, 33, 39, 43, 44). While the pathogenicity of some newly characterized human viruses has been demonstrated, it remains unknown or controversial for other viruses, which may be commensal or pathogenic in only a very small fraction of infections (25,32,40,42,45). Genetic characterization of previously unknown viruses allows the rapid design of nucleic acid tests needed to determine their association with different medical conditions, their presence in different populations, and the design of antibody tests for determining seroprevalence (25, 28, 34, 35, 47).Using sequence-independent PCR amplification, pyrosequencing, and sequence similarity searches (46) (see the text in the supplemental material), we analyzed the virus sequences present in 95 stool samples from Nigerian children suffering from nonpolio acute flaccid paralysis (AFP). Sequences derived from a 10-month-old female child exhibiting right-side asymmetric sudden flaccid paralysis (patient no. NG-J1) formed a 6,981-bp contig consisting of 2,903 individual sequence reads, which was distantly related to sequence of the Aichi virus species in the Kobuvirus genus of the Picornaviridae family (48, 49). Similar sequences were also observed in a second, 24-month-old patient with right-side asymmetric sudden flaccid paralysis (patient no. NG-F1). Gaps between sequenced viral fragments were connected by nested reverse transcription-PCR (RT-PCR), while the 5Ј and 3Ј extremity sequences were acquired using primers designed over conserved regions of bovine, porcine, and human kobuviruses. We temporarily named these viruses saliviruses (stool Aichi-like viruses).The resulting salivirus genome, NG-J1, was 7,124 bp in length with a GC content of 57%, excluding a poly(A) tail. NG-J1 contained a large open reading frame of 7,125 bp encoding a putative polyprotein precursor of 2,374 amino acids (aa), a 5Ј untranslated region (UTR) of 709 bp, and a 3ЈUTR of 148 bp (Fig. 1).NG-J1 and NG-F1 were highly similar, with nucleotide similarities of 94% and 95% in the P1 and P3 regions, respectively. Salivirus NG-J1 had approximately 90% nucleotide similarity to the recently described klasse...
The Wilderness Medical Society convened an expert panel to develop a set of evidence-based guidelines for prevention and treatment of frostbite. We present a review of pertinent pathophysiology. We then discuss primary and secondary prevention measures and therapeutic management. Recommendations are made regarding each treatment and its role in management. These recommendations are graded on the basis of the quality of supporting evidence and balance between the benefits and risks or burdens for each modality according to methodology stipulated by the American College of Chest Physicians. This is an updated version of the guidelines published in 2014.
This analysis of morbidity associated with oral ingestion of pathogens abroad determines which parts of the world currently are high-risk destinations.
To the best of our knowledge, this outbreak is the largest single-point source outbreak of multidrug-resistant typhoid fever yet reported, and it was molecularly traced to the city's single municipal water supply. Isolates were uniformly resistant to nalidixic acid, there was a decrease in their susceptibility as measured by MIC of fluoroquinolones, and 90% of isolates obtained were resistant to >1 antibiotic.
Men and women present with different profiles of travel-related morbidity. Preventive travel medicine and future travel medicine research need to address gender-specific intervention strategies and differential susceptibility to disease.
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