Humans ; Paratyphoid Fever ; epidemiology ; prevention & control ; Public Health Surveillance ; methods ; Typhoid Fever ; epidemiology ; prevention & control

OBJECTIVEThis study was to evaluate the effects of prevention and control regarding programs on typhoid fever and paratyphoid fever, in Guizhou province, from 2007 to 2012, to provide evidence for the improvement of related programs.

METHODSData on typhoid fever and paratyphoid including information on epidemics, individual, cases, measures for prevention and control programs taken and relative government documents were collected and analyzed in Guizhou province, from 2007 to 2012. Information related to the average annual incidence, nature of outbreaks, time span before confirmed diagnosis was made, unit which carried the case report, proportion of laboratory confirmed diagnosed cases and case-management were compared between 2007-2009 and 2010-2012 descriptively while chi-square test with Excel and EpiInfo software were used for data analysis.

RESULTSIn the period of 2007-2009, a total of 5 978 typhoid fever and paratyphoid fever cases were reported in Guizhou province with the average yearly incidence as 5.29/100 000. In the period of 2010-2012, 2 765 cases were reported with the average yearly incidence as 2.57/100 000. When compared to the former, data from the latter period showed that the average yearly incidence had declined 51.31% in all the prefectures. There were still some outbreaks appeared but the total number of cases involved reduced 87.50%. The time span before the confirmation of diagnosis became shorter but the difference was not statistically significant (χ² = 0.08, P = 0.99). Number of cases reported by hospitals at county or above had 11.51% of increase while those cases reported at the township hospitals or below decreased for 61.47% . The proportion of laboratory diagnosed cases increased 23.63%. Rates of timeliness on cards being filled in, input and audited showed increase of 8.44%, 6.76% and 2.40% respectively.

CONCLUSIONSuccessful measures for prevention and control on typhoid fever and paratyphoid fever had been remarkably taken in Guizhou province, but the potential risk of outbreaks still existed in some areas, suggesting that health education and surveillance programs including laboratory diagnosis, should be strengthened.

China ; epidemiology ; Communicable Disease Control ; methods ; Humans ; Paratyphoid Fever ; epidemiology ; prevention & control ; Typhoid Fever ; epidemiology ; prevention & control

OBJECTIVETo understand the incidence rates of both typhoid fever and paratyphoid fever in the high prevalent areas of Guizhou province so as to provide evidence for the development of programs on comprehensive intervention and effectiveness evaluation.

METHODSSix townships in Pingba county were selected as intervention areas while six townships in Kaiyang county were taken as control. All hospitals and clinics were classified into A, B and C types according to its level and the capacity of the blood culture. Surveillance on typhoid and paratyphoid fever was conducted based on all population and all hospitals, clinics and county CDCs among the patients with unknown fever.

RESULTSIn the surveillance area in those two counties, there were 12 944 blood samples from patients with unknown fever which have been tested and cultured. Among them, 200 strains of Salmonella including 16 typhoid strains, 184 paratyphoid A strains were identified, with the total positive rate as 1.55%. The positive rate before the intervention program was higher than the after. The detection rate was 1.91% in the type A hospitals. 39 strains of Salmonella have been cultured from 2039 samples which accounting for 19.50% (39/200) of the total strains. 4315 blood samples were cultured at the 'Class B' sites which isolated 82 strains of Salmonella, accounting for 41.00% (82/200), with a detection rate as 1.90%. 6590 samples were cultured at the 'Class C' sites, which identified 79 strains of Salmonella, accounting for 39.50% (79/200), with a detection rate as 1.20%. The detection rate was much higher before the use of antibiotics than after using them (P < 0.05). The annual peak time of positive detection was in spring and fall. The outbreaks or epidemics often appeared in the same places, with farmers, students as the high-risk populations. Symptoms of both typhoid and paratyphoid fever were not typical.

CONCLUSIONTyphoid and paratyphoid monitoring programs which covered primary health care institutions in the high incidence area seemed to be effective in reflecting the pictures as well as the burden of both typhoid and paratyphoid.

Adolescent ; Adult ; Child ; Child, Preschool ; China ; epidemiology ; Female ; Fever ; epidemiology ; Humans ; Incidence ; Male ; Middle Aged ; Paratyphoid Fever ; epidemiology ; prevention & control ; Population Surveillance ; Salmonella paratyphi A ; isolation & purification ; Salmonella typhi ; isolation & purification ; Typhoid Fever ; epidemiology ; prevention & control ; Young Adult

OBJECTIVETo describe the design and application of cluster randomized controlled method on typhoid Vi vaccine trial, and to assess the effect of implementation.

METHODSSimple size calculation of cluster-randomized trial was used to determine the sample size of the two groups and a vaccination campaign was conducted. The study group was given typhoid Vi vaccine and the control group was given meningococcal A vaccine.

RESULTSAccording to sample size calculation, a total sample of 96,121 participants was required and the study areas were divided into 108 clusters. In practice, 53 study clusters with 44,054 participants and 54 control clusters with 48,422 participants were stratified and matched according to size, location (urban or rural), characteristics (school, department, factory, demography) were randomized respectively. Confounding factors of two groups including age, sex, resident area, income, level of education were compared. It was found that the ratio of all confounding factors between the two groups were comparable and balanced.

CONCLUSIONConfounding factors can be better controlled between study group and the control group by applying cluster-randomized method on vaccine trail which enabled the intervention to be more scientifically evaluated; The implementation of cluster randomization trial was simple and easy to be accepted.

Adolescent ; Adult ; Child ; Child, Preschool ; China ; Cluster Analysis ; Female ; Humans ; Male ; Mass Vaccination ; organization & administration ; Middle Aged ; Polysaccharides, Bacterial ; immunology ; Typhoid Fever ; prevention & control ; Typhoid-Paratyphoid Vaccines ; immunology ; Vaccination

The immunogenicity of a single dose of Salmonella typhi(S.typhi) Vi capsular polysaccharide(CPS) vaccine was evaluated before, and at 1, 3, 12, and 36 months after vaccination. Eighty-five adults(20-28 years of age) and sixty-four children(8-16 years of age) received a single dose of 25 micrograms Vi CPS vaccine intramuscularly, and antibody titers to Vi CPS were measured by passive hemagglutination. Of 149 vaccinees, 138(92.6%) showed seroconversion at 1 month after vaccination, and then 138 out of 141(97.9%) did at 3 months. Of 137 vaccinees, 116(84.7%) maintained a persistent rise in Vi antibody titer 12 months after vaccination, and 55 out of 100(55.0%) had a 4-fold or greater rise at 36 months. No significant adverse reactions were observed. Booster injection may be needed 3-5 years after vaccination.
Adolescent ; Adult ; Antibodies, Bacterial/blood ; Antigens, Bacterial/immunology ; Child ; Evaluation Studies ; Human ; Polysaccharides, Bacterial/*immunology ; Salmonella typhi/*immunology ; Typhoid Fever/prevention & control ; Typhoid-Paratyphoid Vaccines/adverse effects/immunology/*therapeutic use

INTRODUCTIONWe studied the epidemiological trends of enteric fevers (typhoid and paratyphoid fever) in Singapore from 1990 to 2009 and carried out a review of the current prevention and control measures.

MATERIALS AND METHODSEpidemiological records of all reported enteric fevers maintained by the Communicable Diseases Division, Ministry of Health from 1990 to 2009 were analysed.

RESULTSA total of 2464 laboratory confirmed cases of enteric fevers (1699 cases of typhoid and 765 cases of paratyphoid) were reported. Of these, 75% were imported, mainly from India and Indonesia. There had been a significant fall in the mean annual incidence rate of indigenous enteric fevers from 4.3 per 100,000 population in 1990 to 0.26 per 100,000 population in 2009 (P <0.005) with a corresponding increase in the proportion of imported cases from 71% between 1990 and 1993 to 92% between 2006 and 2009 (P <0.0005). Imported cases involving foreign contract workers increased significantly from 12.8% between 1990 and 1993 to 40.4% between 2006 and 2009 (P <0.0005).

CONCLUSIONSingapore has experienced a marked decline in the incidence of enteric fevers that is now comparable to that of other developed countries. Continued vigilance and proactive measures that address the changing epidemiology of enteric fevers in Singapore are necessary to sustain the milestone achieved in the past 2 decades.

Adolescent ; Adult ; Child ; Child, Preschool ; Disease Outbreaks ; Epidemiologic Studies ; Female ; Humans ; Incidence ; Infant ; Infant, Newborn ; Male ; Middle Aged ; Paratyphoid Fever ; epidemiology ; prevention & control ; Population Surveillance ; Singapore ; epidemiology ; Typhoid Fever ; epidemiology ; prevention & control ; Young Adult

This experiment was conducted to assess the efficacy of typhoid vaccine newly produced by purifying Vi antigen of Salmonella typhi. With Karber method, LD50 of challenging organism (S. typhi ty2) was determined as 6.31 CFU/mouse, and then the organism was used for the study. With Probits method, ED50 of the vaccine was determined as 0.016 microgram / 0.5 ml / mouse. The ELISA titer (0.5097+/-0.0606) was 4 times in the group treated with high dose (0.25 microgram/0.5ml) as in control (0.1113+/-0.0110). Six major protein bands of 66, 55, 35, 33, 18, and 9 kd were detected in Western blot analysis with serum of a vaccine treated mouse, whereas only one weak band of about 35 kd was detected with serum of a control mouse. We concluded that typhoid vaccine produced by purifying Vi antigen of S. typhi very effectively prevent S. typhi infection in mice.
Animals ; Antibodies, Bacterial/immunology ; Antigens, Bacterial/*immunology/*isolation&purification ; Blotting, Western ; Enzyme-Linked Immunosorbent Assay ; Lethal Dose 50 ; Logistic Models ; Male ; Mice ; Mice, Inbred BALB C ; Polysaccharides, Bacterial/*immunology/*isolation&purification ; Salmonella typhi/chemistry/*immunology ; Typhoid Fever/immunology/prevention&control ; Typhoid-Paratyphoid Vaccines/administration & dosage/*immunology/*isolation&purification

INTRODUCTIONEnteric fever is a multisystemic infection which largely affects children. This study aimed to analyse the epidemiology, clinical presentation, treatment and outcome of paediatric enteric fever in Singapore.

MATERIALS AND METHODSA retrospective review of children diagnosed with enteric fever in a tertiary paediatric hospital in Singapore was conducted from January 2006 to January 2012. Patients with positive blood cultures for Salmonella typhi or paratyphi were identified from the microbiology laboratory information system. Data was extracted from their case records.

RESULTSOf 50 enteric fever cases, 86% were due to Salmonella typhi, with 16.3% being multidrug resistant (MDR) strains. Sixty-two percent of S. typhi isolates were of decreased ciprofloxacin susceptibility (DCS). Five cases were both MDR and DCS. The remaining 14% were Salmonella paratyphi A. There were only 3 indigenous cases. Ninety-four percent had travelled to typhoid-endemic countries, 70.2% to the Indian subcontinent and the rest to Indonesia and Malaysia. All patients infected with MDR strains had travelled to the Indian subcontinent. Anaemia was a significant finding in children with typhoid, as compared to paratyphoid fever (P = 0.04). Although all children were previously well, 14% suffered severe complications including shock, pericardial effusion and enterocolitis. None had typhoid vaccination prior to their travel to developing countries.

CONCLUSIONEnteric fever is largely an imported disease in Singapore and has contributed to significant morbidity in children. The use of typhoid vaccine, as well as education on food and water hygiene to children travelling to developing countries, needs to be emphasised.

Adolescent ; Anemia ; epidemiology ; Anti-Bacterial Agents ; therapeutic use ; Child ; Child, Preschool ; Drinking Water ; Drug Resistance, Multiple, Bacterial ; physiology ; Enterocolitis ; epidemiology ; Female ; Food Contamination ; Health Education ; Hospitals, Pediatric ; Humans ; India ; Indonesia ; Infant ; Malaysia ; Male ; Paratyphoid Fever ; drug therapy ; epidemiology ; microbiology ; Pericardial Effusion ; epidemiology ; Retrospective Studies ; Salmonella paratyphi A ; physiology ; Salmonella typhi ; physiology ; Shock ; epidemiology ; Singapore ; epidemiology ; Tertiary Care Centers ; Travel ; Typhoid Fever ; drug therapy ; epidemiology ; microbiology ; prevention & control ; Typhoid-Paratyphoid Vaccines ; therapeutic use

OBJECTIVETo study the regulating effects of a novel CpG oligodeoxynuleotide and the synergistic effect of chitosan-nanoparticles (CNP) with CpG on immune responses of mice, which were used to develop a novel immunoadjuvant to boost immune response to conventional vaccines.

METHODSA novel CpG ODN containing 11 CpG motifs was synthesized and its bioactivities to stimulate the proliferation of lymphocytes of pig in vitro were detected. Then it was entrapped with CNP prepared in our laboratory by the method of ionic cross linkage, and immunized Kunming mice were co-inoculated with paratyphoid vaccine. The peripheral blood was collected weekly from the tail vein of inoculated mice to detect the contents of IgG, IgA, IgM, and specific antibody against salmonella as well as the levels of interleukin-2 (IL2), IL-4, and IL-6 by SABC-ELISA assay. The numbers of leucocytes, monocytes, granuloytes, and lymphocytes were calculated separately using the routine method. The experimental mice were orally challenged with virulent salmonella 35 days after inoculation.

RESULTSThis CpG ODN could remarkably provoke the proliferation of lymphocytes of pig in vitro in contrast with the control (P < 0.05). Compared with those of the control, immunoglobulins, including IgG, IgA, IgM, and specific antibodies to paratyphoid vaccine, increased significantly in sera from the CpG or CpG-CNP-vaccinated mice (P < 0.05). IL-2, IL-4, and IL-6 increased remarkably in sera from immunized mice (P < 0.05). The leucocytes, monocytes, granuloytes, and lymphocytes of the mice immunized with CpG or CpG-CNP were also increased in number (P < 0.05). After the challenge, these immunity values were elevated in the mice vaccinated with CpG or CpG-CNP. The immunized mice all survived, while the control mice fell ill with evident lesions with diffuse hemorrhage in stomach, small intestine, and peritoneum.

CONCLUSIONSCpG ODN entrapped with CNP is a promising effective immunoadjuvant for vaccination, which promotes humoral and cellular immune responses, enhances immunity and resistance against salmonella by co-administration with paratyphoid vaccine.

Adjuvants, Immunologic ; administration & dosage ; pharmacology ; Animals ; Antibodies, Bacterial ; blood ; Cell Proliferation ; Chitosan ; chemistry ; Drug Therapy, Combination ; Enzyme-Linked Immunosorbent Assay ; Immunoglobulin Isotypes ; blood ; Interleukins ; blood ; Lymphocyte Activation ; drug effects ; Lymphocytes ; cytology ; Mice ; Nanoparticles ; chemistry ; Oligodeoxyribonucleotides ; administration & dosage ; pharmacology ; Paratyphoid Fever ; immunology ; prevention & control ; Salmonella ; physiology ; Salmonella Infections, Animal ; immunology ; prevention & control ; Swine ; immunology ; Typhoid-Paratyphoid Vaccines ; immunology