Development, confirmation, and application of a seeded Escherichia coli process control organism to validate Salmonella enterica serovar Typhi environmental surveillance methods.

Salmonella enterica serovar Typhi (S. Typhi) is the causative agent of Typhoid fever. Blood culture is the gold standard for clinical diagnosis, but this is often difficult to employ in resource limited settings. Environmental surveillance of waste-impacted waters is a promising supplement to clinical surveillance, however validating methods is challenging in regions where S. Typhi concentrations are low. To evaluate existing S. Typhi environmental surveillance methods, a novel process control organism (PCO) was created as a biosafe surrogate. Using a previous described qPCR assay, a modified PCR amplicon for the staG gene was cloned into E. coli. We developed a target region that was recognized by the Typhoid primers in addition to a non-coding internal probe sequence. A multiplex qPCR reaction was developed that differentiates between the typhoid and control targets, with no cross-reactivity or inhibition of the two probes. The PCO was shown to mimic S. Typhi in lab-based experiments with concentration methods using primary wastewater: filter cartridge, recirculating Moore swabs, membrane filtration, and differential centrifugation. Across all methods, the PCO seeded at 10 CFU/mL and 100 CFU/mL was detected in 100% of replicates. The PCO is detected at similar quantification cycle (Cq) values across all methods at 10 CFU/mL (Average = 32.4, STDEV = 1.62). The PCO was also seeded into wastewater at collection sites in Vellore (India) and Blantyre (Malawi) where S. Typhi is endemic. All methods tested in both countries were positive for the seeded PCO. The PCO is an effective way to validate performance of environmental surveillance methods targeting S. Typhi in surface water.

Self-harm and self-poisoning in southern India: choice of poisoning agents and treatment.

OBJECTIVE: To record cases of suicide and attempted suicide among a population of 108 000 people living in a primarily rural area of southern India, with the aim of guiding policies and strategies to restrict access to poisonous compounds at community level. METHOD: Community-based surveillance over a period of 2 years. RESULTS AND CONCLUSION: The overall suicide rate was 71.4 per 100 000 population; the highest burden was among men. Most people died through hanging (81, 54%) and self-poisoning (46, 31%). Of the 46 who died from self-poisoning, 78.3% had taken pesticides and 19.7% had eaten poisonous plants. Eighty per cent of the self-poisoning cases obtained the poisonous substance in or in close proximity to the home, highlighting the importance of safe storage in the domestic environment. Of the 110 fatal and non-fatal self-poisoning cases, 87 (57.5%) were taken for treatment; 50 (57.4%) went to government hospitals and 37 (42.5%) to private facilities. This indicates the importance of including the private sector in the efforts to improve case management. Furthermore, the fact that 31 (67%) of the self-poisoning patients, who eventually died, were alive after 4 h provides an incentive to focus on improved case management and access to health services.

A randomized non-inferiority clinical study to assess post-exposure prophylaxis by a new purified vero cell rabies vaccine (Rabivax-S) administered by intramuscular and intradermal routes.

BACKGROUND: Rabies is a 100% fatal disease but preventable with vaccines and immunoglobulins. We have developed a new purified vero cell rabies vaccine (Rabivax-S) and evaluated its safety and immunogenicity in post-exposure prophylaxis by intramuscular (IM) and intradermal (ID) routes. METHODS: This was a randomized active-controlled non-inferiority study in 180 individuals (age 5years and above) with suspected rabies exposure (90 each with WHO Category II and Category III exposures). The participants received either Rabivax-S (1mL IM; five doses), Rabivax-S (0.1mL ID; eight doses) or purified chick embryo cell vaccine (PCEC, Rabipur®) (1mL IM; five doses). The IM doses were given on Day 0, 3, 7, 14 and 28 while the ID doses were given on days 0, 3, 7 and 28. Category III patients also received a human rabies immunoglobulin (HRIG) on Day 0. Adverse events (AEs) were recorded with diary cards till day 42. Rabies neutralizing antibody levels were measured on day 0, 7, 14, 28 and 42. RESULTS: In both the category II and III patients, the geometric mean concentration (GMC) ratios of Rabivax-S IM and Rabivax-S ID groups to PCEC IM were more than 1, thus proving the non-inferiority. GMCs were similar or higher in Rabivax-S groups at all the time points. Seroresponse against rabies (RFFIT titre⩾0.5IU/mL) was achieved in all participants. Mostly mild local and systemic adverse events were reported across the three groups and all resolved without sequelae. CONCLUSIONS: Rabivax-S was well tolerated and showed immunogenicity comparable to a licensed rabies vaccine by both IM and ID routes in post-exposure prophylaxis. Registry No.: CTRI/2012/11/003135.