Snake Bite in South Asia: A Review

Snake bite is one of the most neglected public health issues in poor rural communities living in the tropics. Because of serious misreporting, the true worldwide burden of snake bite is not known. South Asia is the world's most heavily affected region, due to its high population density, widespread agricultural activities, numerous venomous snake species and lack of functional snake bite control programs. Despite increasing knowledge of snake venoms' composition and mode of action, good understanding of clinical features of envenoming and sufficient production of antivenom by Indian manufacturers, snake bite management remains unsatisfactory in this region. Field diagnostic tests for snake species identification do not exist and treatment mainly relies on the administration of antivenoms that do not cover all of the important venomous snakes of the region. Care-givers need better training and supervision, and national guidelines should be fed by evidence-based data generated by well-designed research studies. Poorly informed rural populations often apply inappropriate first-aid measures and vital time is lost before the victim is transported to a treatment centre, where cost of treatment can constitute an additional hurdle. The deficiency of snake bite management in South Asia is multi-causal and requires joint collaborative efforts from researchers, antivenom manufacturers, policy makers, public health authorities and international funders

Chromosome map of the Siamese cobra: did partial synteny of sex chromosomes in the amniote represent “a hypothetical ancestral super-sex chromosome” or random distribution?

Background Unlike the chromosome constitution of most snakes (2n=36), the cobra karyotype shows a diploid chromosome number of 38 with a highly heterochromatic W chromosome and a large morphologically different chromosome 2. To investigate the process of sex chromosome differentiation and evolution between cobras, most snakes, and other amniotes, we constructed a chromosome map of the Siamese cobra (Naja kaouthia) with 43 bacterial artificial chromosomes (BACs) derived from the chicken and zebra finch libraries using the fluorescence in situ hybridization (FISH) technique, and compared it with those of the chicken, the zebra finch, and other amniotes. Results We produced a detailed chromosome map of the Siamese cobra genome, focusing on chromosome 2 and sex chromosomes. Synteny of the Siamese cobra chromosome 2 (NKA2) and NKAZ were highly conserved among snakes and other squamate reptiles, except for intrachromosomal rearrangements occurring in NKA2. Interestingly, twelve BACs that had partial homology with sex chromosomes of several amniotes were mapped on the heterochromatic NKAW as hybridization signals such as repeat sequences. Sequence analysis showed that most of these BACs contained high proportions of transposable elements. In addition, hybridization signals of telomeric repeat (TTAGGG)n and six microsatellite repeat motifs ((AAGG)8, (AGAT)8, (AAAC)8, (ACAG)8, (AATC)8, and (AAAAT)6) were observed on NKAW, and most of these were also found on other amniote sex chromosomes. Conclusions The frequent amplification of repeats might involve heterochromatinization and promote sex chromosome differentiation in the Siamese cobra W sex chromosome. Repeat sequences are also shared among amniote sex chromosomes, which supports the hypothesis of an ancestral super-sex chromosome with overlaps of partial syntenies. Alternatively, amplification of microsatellite repeat motifs could have occurred independently in each lineage, representing convergent sex chromosomal differentiation among amniote sex chromosomes

Molecular epidemiology of coagulase-negative staphylococcal bacteraemia in a newborn intensive care unit

We isolated 35 coagulase-negative staphylococci (CoNS) over two separate 12-month periods (26 in 1993 and 29 in 1996) from the blood of neonates in a neonatal intensive case unit (NICU) in Melbourne, Australia and compared them by pulse-field gel electrophoresis profile (PFGE), random amplification of polymorphic DNA (RAPD) and antibiogram. The most common species were Staphylococcus epidermidis, S. haemolyticus and S. warneri. The majority of such isolates were resistant to penicillin and to either or both of methicillin and gentamicin. During 1993, there was an increase in the number of CoNS bloodstream infections compared with previous years. S. epidermidis was the most common isolate, with 88% assessed as clinically relevant. Using the three typing systems, we identified one likely epidemic clone of S. epidermidis, the isolates of which were resistant to penicillin, gentamicin and erythromycin and possessed the mecA gene. There was complete correlation between the detection of mecA and the phenotypic expression of resistance when zone diameters in the disc diffusion assay were interpreted according to the latest NCCLS guidelines (1999). Profiles of the remaining 1993 isolates were generally heterogeneous, suggesting independent acquisition with some evidence of cross-infection. The predominant bloodstream isolates in 1996 were heterogeneous multiresistant strains of S. epidermidis, S. haemolyticus and S. warneri, about half of which were assessed as clinically relevant. These data support the view that CoNS are significant nosocomial pathogens in NICU and that resistant clones may be transmitted between babies. Molecular epidemiological tools are helpful for understanding transmission patterns and sources of infection, and are useful for measuring outcomes of intervention strategies implemented to reduce nosocomial CoNS sepsis. PFGE was found to be more discriminatory than RAPD, but the latter provides results in a more timely manner