Global burden of Shigella infections: implications for vaccine development and implementation of control strategies.

Few studies provide data on the global morbidity and mortality caused by infection with Shigella spp.; such estimates are needed, however, to plan strategies of prevention and treatment. Here we report the results of a review of the literature published between 1966 and 1997 on Shigella infection. The data obtained permit calculation of the number of cases of Shigella infection and the associated mortality occurring worldwide each year, by age, and (as a proxy for disease severity) by clinical category, i.e. mild cases remaining at home, moderate cases requiring outpatient care, and severe cases demanding hospitalization. A sensitivity analysis was performed to estimate the high and low range of morbid and fatal cases in each category. Finally, the frequency distribution of Shigella infection, by serogroup and serotype and by region of the world, was determined. The annual number of Shigella episodes throughout the world was estimated to be 164.7 million, of which 163.2 million were in developing countries (with 1.1 million deaths) and 1.5 million in industrialized countries. A total of 69% of all episodes and 61% of all deaths attributable to shigellosis involved children under 5 years of age. The median percentages of isolates of S. flexneri, S. sonnei, S. boydii, and S. dysenteriae were, respectively, 60%, 15%, 6%, and 6% (30% of S. dysenteriae cases were type 1) in developing countries; and 16%, 77%, 2%, and 1% in industrialized countries. In developing countries, the predominant serotype of S. flexneri is 2a, followed by 1b, 3a, 4a, and 6. In industrialized countries, most isolates are S. flexneri 2a or other unspecified type 2 strains. Shigellosis, which continues to have an important global impact, cannot be adequately controlled with the existing prevention and treatment measures. Innovative strategies, including development of vaccines against the most common serotypes, could provide substantial benefits.     

Building small dams can decrease malaria: a comparative study from Sundargarh District, Orissa, India

The adverse health effect of environmental changes brought about with the construction of large and small dams has often been reported. Here, we present results of a 5-year (2001-2005) study documenting the positive effect of such developmental projects in reducing malaria in an area where malaria transmission is mainly due to the highly efficient anthropophagic vector Anopheles fluviatilis with some contribution from Anopheles culicifacies. The former breeds exclusively in the slow-flowing streams and the latter breeds in a variety of habitats. The study was conducted in San Dulakudar village and comparisons were made with two control villages situated near the stream with similar topography and malaria transmission pattern. Epidemiological data was collected through longitudinal weekly surveillance and cross-sectional surveys in all the study villages. The mean annual malaria incidence rates due to Plasmodium falciparum in children of 1-5 years age group during 2001 before construction of dam was 1304.3 and 785.7 cases/1000 population in dam site village and control villages, respectively. However, after construction of dam, there was gradual reduction in the malaria cases in dam site village and during 2005 the incidence was significantly reduced to 181.8 (P<0.01) whereas it was increased to 1000 in control villages without any significant change in comparison to baseline year (P>0.05). A significant reduction in malaria incidence and parasite rate was also recorded in all the age groups in dam site village without registering any significant change in control villages. The construction of a small dam in the study village altered the water flow above and below the dam thereby making it unfavourable for the breeding of A. fluviatilis which in turn brought about significant impact on malaria transmission.     

Salmonella enterica Serovar Enteritidis,England and Wales, 1945–2011

In England and Wales, the emergence of Salmonella enterica serovar Enteritidis resulted in the largest and most persistent epidemic of foodborne infection attributable to a single subtype of any pathogen since systematic national microbiological surveillance was established. We reviewed 67 years of surveillance data to examine the features, underlying causes, and overall effects of S. enterica ser. Enteritidis. The epidemic was associated with the consumption of contaminated chicken meat and eggs, and a decline in the number of infections began after the adoption of vaccination and other measures in production and distribution of chicken meat and eggs. We estimate that >525,000 persons became ill during the course of the epidemic, which caused a total of 6,750,000 days of illness, 27,000 hospitalizations, and 2,000 deaths. Measures undertaken to control the epidemic have resulted in a major reduction in foodborne disease in England and Wales.     

Phenotypic variability in P. vivax with short- and long-term incubation period

The combined transmission of P. vivax phenotypes was studied. The phenotypes were determined by the duration of a latent parasitic development stage by comparing the intervals from first manifestations of malaria with short- and long-term incubations to its relapse. The study used data on 2493 patients treated with chloroquine (900 mg base for adults) alone at follow-ups in the North-Eastern Delhi (India) in 1988-1992. The combined transmission of P. vivax phenotypes was shown to differ in malaria with short- and long-term incubation. The P. vivax phenotype with manifestations on an average a year following infection in patients with mainly short-term incubation malaria and that with manifestations on an average year and a half after infection in a group of patients with primary long-term incubation malaria were significantly more frequently. Long-term incubation malaria shows simultaneously a larger number of phenotypes than does short-term incubation one. Patients with long-term incubation malaria display a combination of 2 phenotypes (6%) significantly less frequently than that of 3 different phenotypes or more (17%). The similar combinations were observed in the equal number of patients with short-term incubation malaria (7%).     

A phase II study of gemcitabine and 5-fluorouracil in metastatic pancreatic cancer: an Eastern Cooperative Oncology Group Study (E3296)

Gemcitabine has recently been compared favorably to 5-fluorouracil (5-FU) as the standard chemotherapy for advanced pancreas cancer. Based on phase I data that combining gemcitabine with 5-FU is safe and has evidence for clinical activity, a phase II trial was conducted by the Eastern Cooperative Oncology Group (ECOG). Patients with metastatic disease, good performance status and organ function were eligible and enrolled after providing informed consent. Patients were given gemcitabine (1,000 mg/m(2)) followed by 5-FU (600 mg/m(2)) weekly for 3 weeks of every 4. Of 37 patients enrolled over a 3-month period, 36 were eligible. Partial responses were seen in 5 patients (14%). Median survival was 4.4 months with a 1-year survival rate of 8.6%. A randomized trial of the combination of 5-FU and gemcitabine versus gemcitabine alone is currently accruing patients in ECOG.     

Larvivorous fish in wells target the malaria vector sibling species of the Anopheles culicifacies complex in villages in Karnataka, India

Malaria was a major problem in a sericulture area of Karnataka, south India, where Anopheles culicifacies s.l. and A. fluviatilis s.l. were considered to be the main vectors. Sibling species complexes of these two species were analysed in three ecologically different villages. Among A. culicifacies, only sibling species A and B were found. In Puram, a village with 22 wells, species A predominated; species B predominated in a village with four wells and a stream, and in a village with a stream and no wells. Poecilia reticulata fish were introduced into all wells and streams in the villages, and after one year no vectors were found in Puram, and all, or nearly all, A. culicifacies were species B in the other two villages. All A. fluviatilis belonged to the sibling species T. Blood meal analysis indicated that a few of the A. culicifacies collected had fed on humans while all the A. fluviatilis had fed on bovines. Before the introduction of fish, the annual parasite incidence for malaria was high in Puram, but much lower in the other two villages. From 1998 (over one year after release of fish) until 2003, no malaria cases were detected in the three villages.     

Foodborne general outbreaks of Shiga toxin-producing Escherichia coli O157 in England and Wales 1992-2002: where are the risks?

Between 1 January 1992 and 31 December 2002, Shiga toxin-producing Escherichia coli O157 (STEC O157) accounted for 44 of the 1645 foodborne general outbreaks of infectious intestinal disease reported to the Health Protection Agency Communicable Disease Surveillance Centre. These outbreaks, although rare, were characterized by severe infection, with 169 hospital admissions and five deaths reported. STEC O157 outbreaks were compared with other pathogens to identify factors associated with this pathogen. Single risk variable analysis and logistic regression were employed. Two distinct aetiologies were identified. Foodborne outbreaks of STEC O157 infection in England and Wales were independently associated with farms, which related to milk and milk products, and with red meats/meat products, which highlighted butchers' shops as a cause for concern. The introduction and adherence to effective control measures, based on the principles of hazard analysis, provide the best means of minimizing the risk of foodborne infection with this pathogen.