From a literature review of the current literature, this article provides an introduction to vaccine immunology including a primer on the components of the immune system, passive vs. active immunization, the mechanism(s) by which immunizations stimulate(s) immunity, and the types of vaccines available. Both the innate and adaptive immune subsystems are necessary to provide an effective immune response to an immunization. Further, effective immunizations must induce long-term stimulation of both the humoral and cell-mediated arms of the adaptive system by the production of effector cells and memory cells. At least seven different types of vaccines are currently in use or in development that produce this effective immunity and have contributed greatly to the prevention of infectious disease around the world.

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Objectives: This study was designed to review previous studies and analyse the current knowledge and controversies related to seasonal variability of tuberculosis (TB) to examine whether TB has an annual seasonal pattern. Study Design and Methods: Systematic review of peer reviewed studies identified through literature searches using online databases belonging to PubMed and the Cochrane library with key words "Tuberculosis, Seasonal influence" and " Tuberculosis, Seasonal variation". The search was restricted to articles published in English. The references of the identified papers for further relevant publications were also reviewed. Results: Twelve studies conducted between the period 1971 and 2006 from 11 countries/regions around the world (South Western Cameroon, South Africa, India, Hong Kong, Japan, Kuwait, Spain, UK, Ireland, Russia, and Mongolia) were reviewed. A seasonal pattern of tuberculosis with a mostly predominant peak is seen during the spring and summer seasons in all of the countries (except South Western Cameroon and Russia). Conclusions: The observation of seasonality leads to assume that the risk of transmission of M. tuberculosis does appear to be the greatest during winter months. Vitamin D level variability, indoor activities, seasonal change in immune function, and delays in the diagnosis and treatment of tuberculosis are potential stimuli of seasonal tuberculosis disease. Additionally, seasonal variation in food availability and food intake, age, and sex are important factors which can play a role in the tuberculosis notification variability. Prospective studies regarding this topic and other related subjects are highly recommended.

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Introduction: Candida species are normal inhabitants of the skin and mucosa. The importance of epidemiological monitoring of yeasts involved in pathogenic processes is unquestionable due to the increase of these infections over the last decade; Materials and Methods: The clinical samples from the respiratory tract (sputum, bronchial wash, tracheal secretions), saliva, blood, urine, middle ear discharge, vitreous fluid, corneal ulcer, and plastic devices (endotracheal tube, catheter tip, suction tip) were collected and cultured. The species of Candida isolated were identified. Results: A total of 111 isolates of Candida species were recovered from 250 diverse clinical sources. C. albicans (39.64%) was the most isolated species, although the Candida non albicans species with 60.36% showed the major prevalence. In blood cultures, C. krusei (38.23%) and C. albicans (20.58%) were isolated frequently. C. albicans (63.27%) was the predominant species in mucosal surface. Urinary tract infections caused by yeasts were more frequent in hospitalized patients, C. krusei (50.0%) being commonly isolated, followed by C. albicans (25.0%). Discussion: Several virulence factors like, biofilm, proteinase, phospholipase, etc. contribute to the pathogenecity. Early detection of virulence factors by Candida is useful in clinical decision making. We therefore have aimed at demonstrating the formation of biofilm using the method proposed by Branchini et al, (1994). The proteinase produced by Candida was estimated as per the method of Staib et al, (1965). Phospholipase assay was carried out as per the method of Samaranayake et al, (2005). Conclusions : The data suggests that the capacity of Candida species to produce biofilm may be a reflection of the pathogenic potential of the isolates. C. krusei and C. tropicalis showed strong slime production. The non-Candida albicans produced more proteinase than C. albicans. C. albicans produced higher levels of phospholipase than non Candida albicans in this study.

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The combination of diphtheria, tetanus, and pertussis vaccines into a single product has been central to the protection of the pediatric population over the past 50 years. The addition of inactivated polio, Haemophilus influenzae, and hepatitis B vaccines into the combination has facilitated the introduction of these vaccines into recommended immunization schedules by reducing the number of injections required and has therefore increased immunization compliance. However, the development of these combinations encountered numerous challenges, including the reduced response to Haemophilus influenzae vaccine when given in combination; the need to consolidate the differences in the immunization schedule (hepatitis B); and the need to improve the safety profile of the diphtheria, tetanus, and pertussis combination. Here, we review these challenges and also discuss future prospects for combination vaccines.

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Background: In children with meningitis, there is a difficulty to verify the etiology as viral or bacterial. Therefore, intensive research has been carried out to find new and rapid diagnostic methods for differentiating bacterial from viral meningitis. Objectives: The aim of this work was to study the behavior of procalcitonin (PCT) and whether it can be used to differentiate children with bacterial from those with viral meningitis. We also compared PCT to C-reactive protein (CRP) and white blood cell count. Patients and Methods: Forty children aged from 4 months to 12 years with clinically suspected meningitis were studied. Lumbar punctures were done for all cases before starting initial antibiotic treatment. According to the results of bacterial cultures and cerebrospinal fluid (CSF) cytochemical profile, our patients were classified into two groups: bacterial meningitis group and viral meningitis group. PCT, CRP, and leukocyte count were measured at the time of admission and after 3 days. Results: PCT levels were significantly higher in patients with bacterial meningitis (mean, 24.8 ng/ml) compared to patients with viral meningitis (mean, 0.3 ng/ml) (P<0.001). PCT levels in bacterial meningitis group decreased after 3 days of starting treatment, but remained higher than viral meningitis group (mean, 10.5 ng/ml). All CSF parameters, blood leukocytes, and CRP showed overlapping values between the two groups. Serum PCT with cut off value >2 ng/ml showed sensitivity, specificity, positive predictive value, and negative predictive value of 100%, 66%, 68%, and 100%, respectively, for the diagnosis of bacterial meningitis. Conclusion: Serum procalcitonin level has a better diagnostic and prognostic value than CRP or leukocyte count to distinguish between bacterial and viral meningitis. It is also a good indicator of the efficacy of treatment of bacterial meningitis.

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Background: In India, a large segment of the population seeks health care services from individual or institutional private health-care providers for health care. We analyzed a nationally representative data to identify the role of private providers in delivering health care for patients with tuberculosis. Materials and Methods: The primary data source for the present analysis was the 60 ^th round of the National Sample Survey. Distribution frequencies were used to analyze the distribution of key sociodemographic variables and multiple logistic regression was used to analyze the association between these variables and healthcare seeking behavior. Results: A sample of 2203 respondents who had received ambulatory care for tuberculosis, and 4568 respondents who had received inpatient treatment were analyzed. About half of the respondents had attended private facilities for TB care. Sociodemographic variables such as paediatric age group, females, higher level of education, and economic groups were associated with attendance at private sector. Dissatisfaction with services in government facilities was cited as the main reason for preferring private facilities. Conclusions: Private providers play an important role in providing health care services to a large proportion of patients with tuberculosis. There is a need for innovative measures to increase participation of the private sector in the national TB control program and to improve the quality of services in government facilities.

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Background: Bacterial infections remain an important cause of pediatric mortality and morbidity. It might be possible to reduce these factors by early diagnosis and proper management. Aim: The aim of the study was to analyze the bacteriological profiles with their antibiogram, and to register the risk factors for septicemia in neonates and infants. Setting and design: This observational cross-sectional study was conducted in a tertiary care teaching hospital at Gangtok, Sikkim, India, and included clinically suspected cases of septicemia in neonates and infants. Materials and Methods: Blood culture reports were studied in 363 cases of clinically suspected septicemia in neonates and infants, using the standard technique of Mackie and McCartney. The antibiotic sensitivity was performed by Kirby-Bauer's disc diffusion method. Risk factors for sepsis in the children were registered. Results: Blood culture was positive in 22% of cases. Gram-negative septicemia was encountered in 61% of the culture-positive cases. Pseudomonas and Enterobacter species were the predominant pathogens amongst gram-negative organisms. Most gram-negative organisms were sensitive to Amikacin, Ciprofloxacin, and Co-trimoxazole. The most common gram-positive organism isolated was Staphylococcus aureus (97%). More than 70% of Staphylococci isolated were resistant to Penicillin, but were sensitive to Clindamycin (70%) and Vancomycin (40%). The most important risk factors of septicemia in our study population were preterm birth (31%), followed by respiratory distress (5%) and low birth weight (4%). Conclusion: As the cultures showed variable antibiogram with complicated patterns of resistance, culture and sensitivity test should be performed in all cases of septicemia.

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Cholera is a substantial health burden in many countries in Africa and Asia, where it is endemic. It is as well responsible for ongoing epidemics in sub-Saharan Africa which are becoming greater in terms of frequency, extension, and duration. Given the availability of two oral cholera vaccines and the new data on their efficacy, field effectiveness, feasibility, and acceptance in cholera-affected populations and in travelers, these vaccines should be used in endemic areas, in travelers for these areas and should be considered in areas at risk for outbreaks. The two vaccines currently available in worldwide are: (1) The killed oral vaccine (Dukoral, licensed by SBL-Sweden to Crucell-Holland) is recommended since 1999 by WHO and consists of a mixture of four preparations of heat or formalin killed whole cell Vibrio cholera O1 (Inaba and Ogaba serotypes, and classical and El Tor biotypes) that are then added with purified recombinant cholera toxin (CT) B subunit. Because CT cross-reacts with Escherichia coli LT the vaccine also provides short-term protection against ETEC (enterotoxigenic E. coli) which is of added benefit for travelers. It is available in more than 60 countries. (2) A bivalent O1 and O139 whole cell oral vaccine without CT B subunit (Shanchol) has been lately developed in Vietnam (licensed by VaBiotech-Viet Nam to Shantha Biotechnics-India. It is available in India and Indonesia. A structured search of papers in PubMed and reports on cholera vaccines by WHO and CDC, as well as critical reading and synthesis of the information was accomplished. Inclusion criteria were defined according to reports quality and relevance.

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Pyogenic liver abscess secondary to dissemination from Sigmoid diverticulitis is rare. Streptococcus anginosus has been linked to abscesses but has been rarely reported from a Sigmoid diverticulitis source. We report a case of liver abscess in which the source was confounding but eventually was traced to Sigmoid diverticulitis on laparotomy.

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Background: Prevalence of methicillin-resistant Staphylococcus aureus (MRSA) strains is reported to be increasing globally. Objectives: The study was conducted to find the magnitude and antibiotic susceptibility pattern of MRSA infection in a referral tertiary care teaching hospital of Sikkim, India. Materials and Methods: In this cross sectional study, 827 clinical specimens were collected from different departments of Central Referral Hospital. One hundred and ninety-six carrier screening nasal swabs were obtained from health care workers of the hospital. Subsequently, the antimicrobial susceptibility test was performed for the confirmed MRSA isolates as per Clinical and Laboratory Standards Institute (CLSI). Results: Methicillin resistance was seen in 152 isolates of S. aureus - 111 from clinical specimens and 41 from carrier screening samples. MRSA positivity among males was significantly higher than females. Extremely significant MRSA-positive cases were observed from ages less than 30 years, in-patient cases, particularly with a stay of more than 15 days and with a previous history of intake of broad spectrum antibiotics. Incidentally, there was no significant difference of MRSA positivity with a previous history of hospitalization. The extent of MRSA and drug resistance pattern was significantly different among various samples of S. aureus-positive isolates. The strains tested exhibited decreased susceptibility to vancomycin and imipenem. Most vulnerable of the carrier were the cleaners, that was a significant observation. Incidentally, there was no resistance in the carriers to both vancomycin and imipenem. Conclusion: MRSA is prevalent in our hospital and strains resistant to methicillin and vancomycin were quite high.

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Anemia in tuberculosis is usually anemia of chronic disease. Severe hemolytic anemia is exceedingly rare in tuberculosis patients. We report a patient diagnosed with tubercular lymphadenitis complicated by Coomb's positive hemolytic anemia. Patient responded well to antituberculous treatment. Hematological parameters improved after initiation of antituberculosis treatment. To the best of our knowledge, this is the first case from India of an adult patient with tuberculous lymphadenitis presenting with Coomb's positive hemolytic anemia.

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Background: Soil transmitted helminths (STH) remain a global public health concern in spite of occasional dosing campaigns. Aims: To determine baseline prevalence and intensity of STH infection in east Guatemalan school children, and describe the associated epidemiology of anemia, stunting, and wasting in this population. Setting and design: Ten schools in Izabal province (eastern Guatemala) were identified, and 1,001 school children were selected for this study. Half of the schools were used as clinical testing sites (blood and stool). Materials and Methods: Anthropometric measures were collected from all children. Over 300 children were tested for anemia and 229 for helminth infection. Ova and parasite specimens were examined via Direct, Kato Katz, and McMaster techniques. Hemoglobin was measured from venipuncture following the hemacue system. Statistical analysis: Correlation between infection intensities and growth indicators were examined. Chi Square or t tests were used for bivariate analysis. Multiple logistic regression was performed on significant variables from bivariate techniques. Results: Over two-thirds of school children were positive for infection by any STH. Prevalence of Hookworm was 30%; Ascaris, 52%; and Trichuris, 39%, most as low-intensity infection. Over half of the children were co-infected. In bivariate analysis, anemia was significantly associated with polyparasitism. Conclusions: For a Guatemalan child who experiences a unit decrease in hemoglobin, one expects to see a 24% increase in the odds of being infected with STH, controlling for age, sex, lake proximity, and growth characteristics. Infection with more than one STH, despite low intensity, led to a significant decrease in hemoglobin.

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Background: The world is experiencing a pandemic of chikungunya which has swept across Indian Ocean and the Indian subcontinent. Kerala the southernmost state of India was affected by the chikungunya epidemic twice, first in 2006 and then in 2007. Kerala has got geography and climate which are highly favorable for the breeding of Aedes albopictus, the suspected vector. Aim: The aim of the study was to highlight the various domestic and environmental factors of the families affected by chikungunya in 2007 in Thiruvananthapuram district (rural) of Kerala. Settings and design: This is a cross-sectional survey conducted in Thiruvananthapuram (rural) district during November 2007. Materials and Methods : Samples were selected from field area under three Primary Health Centers. These areas represent the three terrains of the district namely the highland, midland, and lowland. The sample size was estimated to be 134 houses from each study area. The field area of health workers was selected as clusters and six subcenters from each primary health center were randomly selected (lot method). Results and Conclusions: The proportion of population affected by chikungunya fever is 39.9% (38.9-40.9%). The investigators observed water holding containers in the peri-domestic area of 95.6% of the houses. According to regression (binary logistic) analysis, the area of residence [adjusted odds ratio (OR) = 8.01 (6.06-14.60)], residing in a non-remote area [adjusted OR=0.25 (0.16-0.38)], perceived mosquito menace [adjusted OR=3.07 (2.31-4.64)], and containers/tires outside the house [adjusted OR=5.61 (2.74-27.58)] were the independent predictors of the occurrence of chikungunya in households.

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Background: It is believed that all suffer from chickenpox infection in their childhood. Many studies abroad and some in India clearly indicate that many individuals escape the infection in childhood, and thus, remain susceptible in adulthood. Adulthood chickenpox is a more serious infection than childhood. Prior screening of health care workers for the presence of IgG antibodies against Varicella will not only prevent hospital outbreaks but also economic and academic loss faced by the students. This will also have an important implication in terms of patient care as there is a threat of spreading Varicella to immuno-compromised patients. Definite history of prior infection of chickenpox is considered as an indicator for immunity towards the same. However, the reliability of this needs to be tested. Aim: A study to assess the susceptibility of nursing and medical students towards Varicella infection by screening for IgG antibodies against Varicella virus and to identify any risk factors for the same. Settings and design: A hospital-based cross-sectional study in nursing and medical students. Materials and Methods: Total 78 nursing and medical students participated in the study. They were given prestructured and pretested questionnaires. After obtaining informed consent, blood sample was collected and screened for the presence of IgG antibodies against Varicella by Enzyme Linked Immunosorbent Assay (ELISA) by using a commercial kit. Statistical analysis: Epi_info 2002 was used for analysis. Age of the study subjects were summarized as mean age and standard deviation. Susceptibility was analyzed as percentage with 95% confidence interval and Chi Square test was used to find association of susceptibility status with sex and region of residence in childhood. Relevance of definite history as an indicator for immunity was assessed by calculating sensitivity, specificity, positive and negative predictive values with 95% confidence interval. Results: Twenty males (25.6%) and 58 females (74.4%) participated in the study from medical and nursing students. The mean age ± standard deviation of mean was 19.4 ± 1.42 years for female students and 20.8 ± 2.13 years for male students. Total 20 (25.6%) students were found to be susceptible to Varicella with the confidence interval ranging from 15.8% to 35.4%. With respect to the gender of the students, the difference between the susceptibility percentage in female students (32%) and in male students (14.3%) was only a numerical difference and not statistically significant (χ² = 2.098, P=0.147, d.f. = 2). Also, the susceptibility was seen significantly more among Keralite students (Pearson Chi-Square=16.736, d.f=6, P=0.008; Likelihood Ratio=15.086, d.f=6, P=0.035; Fisher's Exact Test=13.569, p=0.022). The sensitivity of definite history of prior chickenpox infection as an indicator of immunity was only 55.17%, with C.I ranging from 43.9% to 66.4%, specificity was 80%, with C.I. ranging from 70.9% to 86%, and positive predictive value was 88.8% with C.I of 81.7% to 89% and negative predictive value of history of 66.6% with C.I. of 56% to 77.2%. Conclusion: Total 20 (25.6%) students were found to be susceptible to Varicella with the confidence interval ranging from 15.8% to 35.4%. Thus, there is a need for vaccination of all susceptible individuals. Definite history of prior chickenpox infection is not a reliable indicator of immunity against the same. The investigators recommend screening for IgG antibodies against Varicella of all students selected for the M.B.B.S. (Bachelor of Medicine and Bachelor of Surgery) and nursing course, and vaccination for susceptible individuals to prevent institutional outbreak and academic loss.

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Tuberculosis of the submandibular salivary gland is a rare condition and only a few cases have been reported in literature. Tubercular sialadenitis is most frequently seen in immunosuppressed patients. Diagnosis of this disease is difficult. Although fine needle aspiration cytology is useful in diagnosis, excisional biopsy is often required. Polymerase chain reaction for mycobacterium tuberculosis is a reliable diagnostic tool, and if available, it should be performed before surgical intervention to enable differential diagnosis of a salivary gland tumor. We report two cases of the submandibular salivary gland tuberculosis from South India (Mangalore located in the coastal belt of Karnataka) that proved diagnostically challenging. Both patients responded well to antitubercular therapy and surgery was avoided.

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Brucellosis continues to be a common infectious disease in some parts of the world. Although the disease has different presentations, but chest wall involvement, as a manifestation of brucellosis is rare. In this study, we report three cases of chest wall involvement as manifesting feature of Brucellosis in Iran. They presented with a history of parasternal masses revealed to a diagnosis of Brucellosis and responded well to the treatment. Brucellosis may present with strange and unpredictable manifestations and can be misdiagnosed with tuberculosis and malignancies, especially in endemic areas for both TB and brucellosis.

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Clinical chorioamnionitis can result either from the ascending organisms from vagina after rupture of membranes or via the blood stream. This report describes a case of chorioamnionitis caused by Arcanobacterium haemolyticum, an unusual organism associated with this infection. A 19-year-old primigravida at 32 weeks of gestation presented with the complaints of fever, pain in the abdomen, and discharge per vaginum for the past 2 days. Watery, odorless, colorless, and discharge passing intermittently were noticed. A. haemolyticum was isolated from amniotic fluid. Upon induction, a healthy male baby weighing 1.9 kg was delivered. The patient was started on gentamicin and metronidazole for 8 days. Recovery was uneventful. The mother and baby were discharged on ninth day. Chorioamnionitis can result in significant maternal and fetal mortality and morbidity. Hence, it is important to ascertain the prompt diagnosis and treatment of suspected cases. Increase in awareness of clinicians and laboratories will reduce misdiagnosis and facilitate appropriate treatment.

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