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Globally, pneumonia is the leading cause of death in young children and burden of disease is disproportionately high in South-East Asia Region of WHO. This review article presents the current status of pneumonia disease burden, risk factors and the ability of health infrastructure to deal with the situation. Literature survey was done for the last 20 years and data from country offices were also collected. The estimated incidence of pneumonia in under five children is 0.36 episodes per child, per year. Risk factors are malnutrition (40% in India), Indoor air pollution, non-breast feeding, chronic obstructive pulmonary disease, etc. Strengthening of health care delivery system for early detection and treatment and as well as minimization of preventable risk factors can avert a large proportion of death due to pneumonia.

a number of studies have shown the association between vitamin A deficiency and the increased risk of diarrhoeal and other childhood morbidities and mortality. However, some studies have raised controversies regarding the reduction of the incidence of diarrhoea after vitamin A supplementation to children. This study was undertaken to evaluate the effectiveness of vitamin A supplementation to young rural children in reducing the incidence of diarrhoea.a double-blind randomized intervention trial was carried out amongst 404 rural children between 6-59 months of age to assess the impact of vitamin A supplementation on morbidity due to diarrhoea. Children aged 6-59 months were enrolled and allocated to receive either 200,000 or 50,000 IU of vitamin A and the same dose was repeated after six months. Morbidity due to diarrhoea was observed by twice-a-week household surveillance, during the subsequent one year of follow up. The incidence of diarrhoea was compared between the two supplemented groups. In addition, the overall incidence of diarrhoea n the two supplemented groups was also compared with the incidence observed during the year preceding supplementation.the incidence of diarrhoea was similar in the two supplemented groups (Incidence Rate Ratio = 1.05. 95% C. I. 0.79-1.40). However, the overall incidence of diarrhoea among all the children in the two supplemented groups (0.56 episodes/child/year) was significantly lower than the incidence before supplementation (1.15 episodes/child/year). The Incidence Rate Ratio was 0.49 with 95% C.I 0.40-0.59.the results of this study indicate that vitamin A supplementation in a dose of 200,000 IU, has no additional advantage over 50,000 IU, at least when the aim is to reduce the incidence of diarrhoea. For control of morbidity due to diarrhoea, vitamin A supplementation in a dose of 50,000 IU every six months appears to be adequate, cost effective and suitable for younger children.

Of the two reservoirs of infection of kala-azar i.e., patients of kala-azar and post kala-azar dermal leishmaniasis (PKDL), PKDL provides easy access for the sandfly to pick up the parasites. In the last epidemic of 1977 in India, the importance of PKDL as a potential cause of increase in number of kala-azar cases was ignored. During recent years, we found an increase in the cases of kalaazar whereas cases of PKDL were decreasing in Bihar. We undertook this study to find out reasons for this phenomenon.These three different settings were selected to study the trends of the disease. (i) Cases of PKDL registered in the Dermatology Department of Patna Medical College Hospital (PMCH), one of the largest and oldest teaching hospital in Bihar, between 1970 and 2005; (ii) Rajendra Memorial Research Institute of Medical Sciences, Patna (RMRIMS), a research institute exclusively devoted to kala-azar (2000 and 2005); and (iii) interviews with two leading dermatologists of Patna selected by lottery on the incidence of PKDL and possible causes of its decrease, if any. The number of cases of kala-azar (visceral leishmaniasis, VL) from Bihar was studied from Malaria Departments of the Government of Bihar and Government of India, the two nodal departments dealing with the kala-azar.Analysis of data from Dermatology Department of PMCH showed increase in number of cases of PKDL from two in 1970 to 12 in 1976, a year before the first epidemic of kala-azar in 1977 with 100,000 cases. Kala-azar cases decreased to 11,120 in 1982 due to control measures taken between 1977- 1979 but cases of PKDL reached 28 and kept on increasing. During 1950 to 1977, low dose and short duration regimen of sodium antimony gluconate (SAG) was mainly used in the treatment of kala-azar. Between 1977-1991 increasing incidence of unresponsiveness to SAG, led to the usage of longer duration and higher dose regimen of SAG, more use of amphotericin B (AMB) for SAG resistant cases and also as a first line drug for kala-azar and PKDL. The number of kala-azar cases started decreasing after control measures taken during 1992-1994 but cases of PKDL continued decreasing. The effect of control measures on the incidence of kala-azar was visible upto 2002, but decrease in number of PKDL cases continued. In 2005 the number of PKDL cases was 14 but number of kala-azar cases reached 21,177 in Bihar. In the interview, the two dermatologists also opined that PKDL was decreasing due to increased use of amphotericin B in the treatment of kala-azar. Trend analysis done on the data of PMCH and RMRIMS showed that PKDL will decrease in coming years and kala-azar will increase.Incidence of PKDL decreased in PMCH and RMRIMS and also suggested by two dermatologists that extensive use of amphotericin B in the treatment of kala-azar might be responsible for decrease in number of cases of PKDL.

Diarrhoeal disease outbreaks are causes of major public health emergencies in India. We carried out investigation of two cholera outbreaks, for identification, antimicrobial susceptibility testing, phage typing and molecular characterization of isolated Vibrio cholerae O1, and to suggest prevention and control measures.A total of 22 rectal swabs and 20 stool samples were collected from the two outbreak sites. The V. cholerae isolates were serotyped and antimicrobial susceptibility determined. Pulsed- field gel electrophoresis (PFGE) was performed to identify the clonality of the V. cholerae strains which elucidated better understanding of the epidemiology of the cholera outbreaks.Both the outbreaks were caused by V. cholerae O1 (one was caused by serotype Ogawa and the other by serotype Inaba). Clinically the cases presented with profuse watery diarrhoea and dehydration. All the tested V. cholerae isolates were sensitive to tetracycline, gentamycin and azithromycin but resistance for ampicillin, co-trimoxazole, nalidixic acid, and furazolidone. PFGE pattern of the isolates from the two outbreaks revealed that they were clonal in origin. Stoppage of the source of water contamination and chlorination of drinking water resulted in terminating the two outbreaks.The two diarrhoeal outbreaks were caused by V. cholerae O1 (Inaba/Ogawa). Such outbreaks are frequently seen in cholera endemic areas in many parts of the world. Vaccination is an attractive disease (cholera) prevention strategy although long-term measures like improvement of sanitation and personal hygiene, and provision of safe water supply are important, but require time and are expensive.

Kolkata and its suburbs in eastern India are known to be endemic for typhoid fever. The objective of this study was to determine phage types, biotypes and antimicrobial resistance patterns of Salmonella enterica serotype Typhi isolated during the period 2003-2005 from a prospective surveillance for typhoid fever in two urban slums in Kolkata.A total of 195 Salmonella enterica serotype Typhi isolated from blood cultures were phage typed, biotyped and tested for their antimicrobial susceptibility profile.Phage type E1 was the most common (60.3%) followed by phage type A among five phage types identified. Biotype I (95%) was predominant, 28 isolates were multidrug resistant (MDR) and most of the MDR strains belonged to phage type E1 and biotype I.A single phage type and biotype were prevalent among the Salmonella enterica serotype Typhi isolates studied from Kolkata, India.

The risk of human immunodeficiency virus (HIV) co-infection in patients with visceral leishmaniasis (VL) or kala-azar in endemic areas has posed a major challenge in control programmes. We undertook this study to identify the high risk groups vulnerable to Leishmania-HIV co-infection in VL endemic State of Bihar, India. Further, immunological responses were also evaluated in these patients before and after treatment for VL to see the immune impairment associated with CD4 T cell count.A total of 1511 subjects attending Voluntary Counselling and Testing Centre (VCTC) at Patna, Bihar were included in this study. VL was confirmed by splenic or bone marrow aspirates testing for parasite. HIV states was confirmed by two kits. Immunological parameters (CD4, CD8, IFN-gamma, IL-4) were studied in co-infection patients.Of the 280 (18.53%) HIV-positive individuals, eight were diagnosed serologically and pathologically as VL patients co-infected with HIV. The humoral and cellular immune responses were evaluated in 18 Indian VL patients with (n = 8) or without HIV (n = 10) and 10 HIV seropositive subjects. Among the eight confirmed cases of VL, false negative direct agglutination test (DAT) result was observed in two who had HIV co-infection (sensitivity 80%), while none in 10 other VL cases who were HIV negative (sensitivity 100%). A very low CD4 cell count was observed in VL cases that had HIV co-infection compared to HIV negative VL or controls. All VL cases with or without HIV infection had lower Th1/Th2 ratio compared to controls. VL patients with or without HIV infection responded well to anti-leishmanial/anti-retroviral therapy with considerable degree of immunological reconstitution.A different immune response was noticed in patients with co-infection of HIV and Leishmania. Anti-leishmanial drug treatment led to improvement in immunological response in co-infected patients. Further studies need to be done to see the effect of combined therapy for VL and HIV on immunological parameters in these patients.

Epidemics of cholera caused by Vibrio cholerae O1 or O139 have been reported from different parts of India. Factors such as unsafe water supply, poor environmental sanitation, indiscriminate defaecation and lack of personal hygiene are mainly responsible for continued transmission of this disease. We report here epidemiological and microbiological findings of a localized outbreak of cholera, which occurred during March and April 2004 in the eastern part of Kolkata city.The affected slum area has a population of 4409, predominantly muslims. Patients suffering from acute watery diarrhoea attended the health outposts organized by National Institute of Cholera and Enteric Diseases, Kolkata and International Vaccine Institute, South Korea as part of a routine surveillance programme at the locality as well as the emergency medical camp organized by the Kolkata Municipal Corporation. Stool and water samples were collected and tested for diarrhoeagenic pathogens in the laboratory. Bacteriophages specific for V. cholerae were isolates and studied electron microscopically for morphology.A total of 89 diarrhoea cases were reported giving an attack rate of 2 per cent. V. cholerae O1 biotype ElTor, serotype Ogawa was isolated as a sole pathogen from 15 (15.8%) of 89 stool samples screened. Water samples (2 from tube wells, 3 from municipal taps and 1 from well) showed presence of coliform bacilli with high MPN (Most Probable Number) count. Bacteriophages specific to V. cholerae were isolated from 2 of 6 water samples examined. A leakage was detected in the main pipeline supplying drinking water to that area.The outbreak was caused by V. cholerae O1 (Ogawa) biotype ElTor. The presence of phages in the water samples was an additional indicator for V. cholerae contamination in this community. Occurrences of such outbreaks support vaccination against cholera as an alternative strategy.

Infectious diseases kill about 11 million children each year while acute diarrhoeal diseases account for 3.1 million deaths in children under 5 yr of age, of which 6,00,000 deaths annually are contributed by shigellosis alone. Shigellosis, also known as acute bacillary dysentery, is characterized by the passage of loose stools mixed with blood and mucus and accompanied by fever, abdominal cramps and tenesmus. It may be associated with a number of complications of which haemolytic uraemic syndrome is the most serious. Shigellosis is caused by Shigella spp. which can be subdivided into four serogroups namely S.sonnei, S.boydii, S.flexneri and S.dysenteriae. Organisms as low as 10-100 in number can cause the disease. Shigellosis can occur in sporadic, epidemic and pandemic forms. Epidemics have been reported from Central American countries, Bangladesh, Sri Lanka, Maldives, Nepal, Bhutan, Myanmar and from the Indian subcontinent, Vellore, eastern India and Andaman and Nicobar islands. Plasmid profile of shigellae in Kolkata has shown a correlation between presence of smaller plasmids and shigellae serotypes- indicating epidemiological changes of the species. Diagnosis of shigellosis is essentially clinical. Laboratory diagnosis includes stool culture and polymerase chain reaction (PCR). Treatment includes use of an effective antibiotic, rehydration therapy (if there is dehydration) and appropriate feeding during and after an episode of shigellosis. Hand-washing is the single most important strategy for prevention of transmission of shigellosis from person to person. A safe and effective vaccine should be developed against the more important circulating strains i.e., S. dysenteriae type 1 and S. flexneri 2a.

Shiga toxin producing Escherichia coli (STEC) is a newly emerged pathogen that has been the focus of immense international research effort driven by its recognition as a major cause of large scale epidemics and thousands of sporadic cases of gastrointestinal illness. It produces a severe bloody diarrhoea that is clinically distinct from other types of diarrhoeal diseases caused by other enteric pathogens. One of the most important areas of current exploration concerns how STEC enters our food chain, an investigational avenue that begins with the ecology of STEC in animals and in the environment. A variety of foods have been identified as vehicles of STEC-associated illness and this makes the organism one of the most serious threats to the food industry in recent years. The pathogenesis of STEC is multifactorial and involves several levels of interaction between the bacterium and the host. STEC strains carry a set of virulence genes that encode the factors for attachment to host cells, elaboration of effective molecules and production of two different types of Shiga toxins. These genes are found in the locus of enterocyte effacement (LEE), lamboid phages, and a large virulence associated plasmid. The publication of the complete genome sequence of Esch. coli O157:H7 chromosome offers a unique resource that will help to identify additional virulence genes, to develop better methods of strain detection and in the understanding of the evolution of Esch. coli through comparison with the genome of the non-pathogenic laboratory strain Esch. coli K-12. These research efforts in turn, should lead to development of new potent and cost effective anti-Stx therapies or vaccines and thereby major improvement in human health world-wide.

Kolkata and its suburbs in eastern India faced an epidemic of typhoid fever in 1990. A prospective, hospital and laboratory based study over a period of 12 yr (1990-2001), on the phage typing and biotyping pattern of Salmonella enterica serotype Typhi was carried out, to see if there has been a change.A total of 338 S. enterica serotype Typhi isolates from 1491 blood samples were phage typed and biotyped. The mean age of isolation was calculated.The age distribution of subjects (neonates to 12 yr) has been analysed. Of the 338 (22.7%) isolates obtained, eight different S. enterica serotype Typhi phage types were detected. Biotype I (95.8%) was more prevalent as compared to biotype II (4.1%). Phage type E1 was the commonest phage type in Kolkata and its suburbs.The mean age at isolation was found to be 6.7 +/- 3.3 yr. Biotype I was predominant and it was of interest that all strains of phage type E1 belonged to biotype I.

In addition to Vibrio cholerae O1, a recently emerged non-O1 serotype, V. cholerae O139 has also been found to be responsible for epidemics of cholera. In the context of the changing etiology of cholera, the occurrence of different serotypes, biotypes and phage types of V. cholerae in Tamil Nadu is presented.Between 1980 and 2001, 26,502 stool/rectal swabs from patients suspected to have cholera were processed for the presence of V. cholerae at the King Institute of Preventive Medicine, Chennai (Madras), Tamil Nadu. Serotypes, biotypes and phage types (BasuMukerjee and new phage typing method) of the isolates were determined. Antimicrobial susceptibility determination was included from 1997 onwards.Of the 26,502 stool/rectal swabs tested, 6035 (22.8%) specimens yielded V. cholerae. 4,046 (67%) of them were O1 serotype; followed by 1529 (25.3%) O139 serotype and 448 (7.4%) non-O1 serotypes other than O139 were encountered. Twelve specimens yielded rough strains of V. cholerae. All V. cholerae O1 were the biotype ElTor and the predominant serotype was Ogawa (95.9%). After the initial explosive epidemic by O139 serotype in late 1992 and early 1993 occurrence of this serotype had declined. Resurgence of this new serotype was observed in 1997. O1 domination was observed during 1995 and 1996. The new phage typing scheme for V. cholerae O1 was able to differentiate the isolates into 22 types, type 27 (68.2%) being the predominant one followed by type 26 (12.3%). In BasuMukerjee scheme, the isolates were clustered between two types--type 2 (34%) and type 4 (61%). Further, about 5 per cent of them were untypeable. All but a few of the isolates irrespective of serotype, were susceptible to chloramphenicol, tetracycline, gentamicin and ciprofloxacin. 97 per cent of the O1 strains and 48.9 per cent of the O139 strains were resistant to cotrimoxazole.V. cholerae O139 might have the ability to survive during interepidemic periods. Both V. cholerae O1 and O139--the two serotypes with epidemic potential seem to be firmly established in this region. This situation warrants constant surveillance.

Different routes for the transmission of HIV-1 in India have been reported and the majority of infections occurred through heterosexual route of transmission. In order to understand the dynamics of HIV-1 transmission, a systematic study was undertaken to determine the viral subtypes circulating among the female sex workers in Calcutta, India.Peptide enzyme immunoassay (PEIA), heteroduplex mobility assay (HMA) and DNA sequence analysis were used to ascertain the HIV-1 subtypes.V3 serotyping of 52 HIV-1 seropositive samples identified 33 (60%) to be subtype C. A DNA fragment within C2-V3/C2-V5 regions of HIV-1 gp120 was amplified directly from the lymphocyte DNA to avoid any bias in selecting viral variants and used in HMA. Of the 40 samples analyzed, 38 (95%) belonged to subtype C and 2 were found to be non-typable. Further analysis of these 38 samples revealed that 26 (68%) had maximum homology to the C3-Indian reference strain (IND868), 11 (29%) were most homologous to C2-Zambian strain (ZM18) and 1 (3%) showed close resemblance to C1-Malawi strain (MA959). Nucleotide sequence of 11 subsamples encompassing about 325 base pairs was aligned for the Indian and other geographically distinct isolates. On distance and parsimony trees, most of the samples (8/11) clustered together as subtype C.Subtype C was the major circulating HIV-1 strain in this geographical region, although variation within this subtype was also noticed. DNA sequence analysis was found to be the best method in determining the nature of the HIV-1 subtype followed by HMA and peptide enzyme immunoassay. These findings may have important implications for the design of effective vaccines in India and emphasizes the need for constant monitoring of the HIV-1 subtypes in different parts of India.

An explosive epidemic of cholera in the district of Malda in the state of West Bengal, was induced by devastating floods resulting from overflowing of the two main rivers of the district, at the end of July 1998, affecting 15 blocks and 2 municipalities. Diarrhoeal outbreak occurred around the middle of August after receding of the flood waters. Within two weeks of its onset, the outbreak spread throughout the district. An investigation was conducted to understand the epidemiological characteristics, identify the etiological agent, rationalise clinical management and suggest control measures.The team visited the Block Primary Health Centres, surrounding the affected villages and also the district hospital. Morbidity and mortality data were collected and 88 patients were interviewed and examined clinically. Epidemiological and clinical observations were recorded. Rectal swabs were collected from both hospitalised and domiciliary cases.During the period between August and October 1998, 16,590 cases were reported with 276 deaths (case fatality rate of 1.7%). Twenty one of 29 (72%) rectal swabs were positive for Vibrio cholerae O1, biotype ElTor, serotype Ogawa. All the strains were sensitive to tetracycline, norfloxacilin, ciprofloxacilin, gentamycin, chloramphenicol but resistant to furazolidine, co-trimoxazole, nalidixic acid, streptomycin and ampicilin.Observations of the present study identified the epidemiological and clinical deficiencies in the management of the outbreak and recommendations were elaborated for its effective control.

An explosive outbreak of diarrhoeal disease which occurred in the Baishnabghata, Patuli area of Kolkata Municipal Corporation during September 28 to October 12, 2000, was investigated by a team from the National Institute of Cholera and Enteric Diseases, Kolkata, to identify the causative agent and determine the antimicrobial susceptibility pattern.Clinical and epidemiological data were collected from domiciliary cases and also from patients attending two medical camps that had been set up for the purpose. Stool and water samples were collected for isolation of diarrhoeagenic pathogens.A total of 710 cases of diarrhoea occurred with an attack rate of 7.1 per cent; majority were adults. All 6 faecal samples and 2 water samples collected, were positive for Vibrio cholerae O139. The strains were uniformly (100%) susceptible to the commonly used drugs for cholera such as tetracycline, norfloxacin, ciprofloxacin, co-trimoxazole and nalidixic acid but resistant (100%) to furazolidone and ampicillin.This is the first localised outbreak of V. cholerae O139 in Kolkata since the devastating epidemic in 1992. Extensive chlorination of all water sources resulted in a dramatic decline of the outbreak. The appearance of resistance in V. cholerae O139 to furazolidone is a matter of great concern since this drug is used for the treatment of cholera in children and pregnant women.

Helicobacter pylori colonizes the gastric mucosa of more than half of all people worldwide and is the major cause of peptic ulcer disease and an early risk factor for gastric cancer, even though most infections are asymptomatic. Infection occurs preferentially in early childhood and once established tends to persist for years or decades. Much of the pathology H. pylori causes probably results from the host response to infection, which is affected by bacterial genotype, human host characteristics and environmental conditions. H. pylori is one of the most genetically diverse of bacterial species, with different genotypes predominating in different parts of the world. In particular, strains from India differ from those of Europe and East Asia in DNA sequence of several diagnostic gene segments. This outcome invites speculation about H. pylori origins and the possibility of Indian-specific genes that might be uncommon in Western strains. Much has been learned from H. pylori genome sequences, along with epidemiological, mutational, molecular and immunologic analyses. Candidate bacterial colonization and virulence genes and host responses are being identified, and the hypotheses being developed are amenable to tests in cell culture and animal models. These research efforts, many of which are collaborative and international, provide insights into mechanisms of establishment and persistence of H. pylori infection and virulence, and should lead to new, far more potent and cost effective anti-Helicobacter therapies or vaccines, and thereby major improvement in human health worldwide.

In a prospective hospital based surveillance, 1454 children clinically diagnosed as typhoid fever were enrolled during the period between 1990 to 2000. Of them 336 (23.1%) children were positive for Salmonella enterica serotype Typhi by blood culture. A declining trend of hospitalization and identification of the pathogen was observed from 1992 to 2000 as compared to 1990-1991. A declining trend of resistance to the commonly used anti-typhoid drugs was seen in the S. enterica serotype Typhi isolates. Recently in 2000, nine strains were detected as ciprofloxacin resistant. Misuse and overuse of ciprofloxacin for the treatment of typhoid fever influenced the development of ciprofloxacin resistant strains of S. enterica serotype Typhi in and around Kolkata.

A highly sensitive bead enzyme-linked immunosorbent assay was applied for the quantitative determination of vacuolating cytotoxin (VacA) released in the culture supernatant of 40 well characterized Helicobacter pylori strains in order to clarify the significance of allelic combination of the vacA gene as the predictor of the level of toxin secretion and also to determine the most appropriate genotype of H. pylori associated with high VacA release. Attempts were also made for the detection of VacA in the gastric juice of patients for the rapid diagnosis of H. pylori infection.The genotypes of 40 H. pylori strains cultured from the gastric biopsy samples were determined by specific PCRs. The cell-free culture supernatant of the strains as well as the gastric juice of the patients were used for bead-ELISA and the purified VacA from the H. pylori strain ATCC49503 was used as positive control.Ninety per cent of the strains with vacAs1m1 allele combination secrete on an average 146.4 ng/ml of VacA while the corresponding value was 19.1 ng/ml for s1m2 strains. None of the s2m2 as well as the ice negative H. pylori strains produced detectable VacA in the medium while strains expressed the toxin irrespective of the presence or absence of cagA gene. Fifteen of 22 gastric juice samples yielded positive bead-ELISA results.vacAs1, vacAm1 and iceA1 could be considered as the determinants of high VacA secretion. Also, the detection of VacA by bead-ELISA in the gastric juice could be considered as an alternative approach in the diagnosis of H. pylori infection.

While investigating a cholera outbreak in south India, toxigenic and nontoxigenic strains of Vibrio cholerae O1 were isolated from patients and from the environment, respectively. This study was performed to compare the genetic relatedness of the patient and environmental strains to determine clonal relationships among these strains and thereby determine the source of the cholera outbreak.The 16 strains of V. cholerae isolated from hospitalized patients and 8 environmental V. cholerae strains isolated from the environment were phenotypically and genotypically characterized using a variety of standard techniques.Sixteen toxigenic clinical strains and 2 nontoxigenic environmental strains belonged to O1 serogroup, Ogawa serotype and El Tor biotype. The remaining 6 nontoxigenic environmental strains were classified as non-O1, non-O139 V. cholerae. The drug resistance pattern of the clinical and environmental strains of V. cholerae showed marked differences with the patient strains being resistant to more number of drugs as compared to the environmental strains. DNA fingerprinting of the strains showed considerable diversity between toxigenic clinical and nontoxigenic environmental O1 Ogawa isolates and between the O1 and non-O1, non-O139 isolates.In this outbreak of cholera, the O1 strains of V. cholerae from clinical and environmental sources belonged to two different clones and the environmental strains could perhaps be the future cholera outbreak causing clones.

The rapid spread of multidrug resistant (MDR) typhoid fever has posed a great challenge for the treatment of these cases the world over. After the emergence of chloramphenicol resistant Salmonella typhi strains, ciprofloxacin has become the drug of choice for the treatment of typhoid fever even in the paediatric age group. This study evaluated the role of ceftriaxone therapy in bacteriologically confirmed MDR typhoid cases who did not respond to 12-14 days of ciprofloxacin therapy. Attempts have also been made to investigate the in vitro susceptibility of isolated S. typhi strains to chloramphenicol, ciprofloxacin and ceftriaxone.A total of 140 children, aged 3-10 yr, clinically diagnosed as having typhoid fever, without any clinical response after 12-14 days of ciprofloxacin therapy were screened for S. typhi by blood culture. In the bacteriologically positive children the treatment was changed to intravenous ceftriaxone for 14 days. The isolated strains of S. typhi were tested for in vitro antimicrobial susceptibility.Clinical and bacteriological cure was observed with intravenous ceftriaxone therapy in all the 32 bacteriologically positive patients. All isolated S. typhi strains were uniformly (100%) susceptible to ciprofloxacin and ceftriaxone but 50 per cent of the strains were resistant to chloramphenicol. The MIC values of chloramphenicol, ciprofloxacin and ceftriaxone ranged between 125-500, 0.0625-0.5 and0.0625 microgram/ml respectively.The study indicates that although the S. typhi strains were susceptible to ciprofloxacin in vitro, the patients did not respond clinically and bacteriologically to ciprofloxacin therapy. Hence, ciprofloxacin may not represent a reliable and useful option for treating MDR typhoid fever; ceftriaxone may be an effective alternative for the treatment of such cases.

Klebsiella pneumoniae strains occasionally cause diarrhoea in humans. This study was done to determine the involvement of calcium in the pathogenesis of aggregative K. pneumoniae strains.A total of nine strains of K. pneumoniae were tested for adherence assay in HeLa cell line. A representative strain CO-1215 was used for [Ca2+]i study using Fura-2 fluorescence.Infection of cultured HeLa cells with aggregative K. pneumoniae strain resulted in five-fold elevation of intracellular level of free calcium ([Ca2+]i) with maximum Ca2+ influx at 3 h after bacterial infection. Chelation of extracellular Ca2+ with [ethylenebis(oxyethylenenitrile)] tetraacetic acid and suspension of cells in Ca2+ free buffer suggested that the rise of Ca2+ in aggregative K. pneumoniae infected HeLa cells was due to influx of Ca2+ from extracellular medium.This study showed aggregative adherence in HeLa cells and this adherence leads to influx of extracellular Ca2+. The unrestricted passage of calcium ions across cell membranes could cause phosphorylation of proteins involved in ion transport across the membrane, which could result in secretory diarrhoea. Further work is in progress to study the enterotoxicity of these strains in an in vitro rabbit intestinal model.

Antimicrobial resistance among Vibrio cholerae has been monitored for several years in Calcutta. To investigate the changing trends in multidrug resistance (MDR) among different serogroups of V. cholerae and to perform software assisted cluster analysis the current study was undertaken.Strains isolated from patients with cholera and "cholera-like" diarrhoea admitted in the Infectious Diseases Hospital, Calcutta were analysed. Eight hundred and forty V. cholerae strains isolated from 1992 through 1997 were tested for susceptibility to 11 antibiotics. Cluster analysis was done using SPSS software.Most of the strains exhibited MDR with fluctuating trends as the resistance profile diverged each year. A total of 119 different resistance profiles exhibited by V. cholerae O1, O139 and non-O1, non-O139 serogroups were analysed by cluster combination method. During 1993 and 1994, 53 per cent of V. cholerae O139 and 82 per cent of V. cholerae O1 serogroups, respectively, exhibited maximal number of new resistance patterns. The frequency of new resistance patterns among V. cholerae non-O1, non-O139 was constantly high (33-47%) during 1995 to 1997.With a few exceptions, preponderance of the resistance profiles was generally not confined to any serogroup. The cluster analysis depicted dissemination of some of the resistance patterns commonly found among V. cholerae non-O1, non-O139 belonging to different serogroups to the O139 serogroup in the succeeding years. In this study we have shown that the V. cholerae strains are resistant to several antibiotics with constant change in the MDR profiles. It is imperative to define the susceptibility pattern of the strains to determine the effective drug of choice for the treatment of cholera.

Detection of faecal leucocytes and RBCs in stool samples of cholera patients has been reported in a small number of studies. This study extends these observations by examining stool samples of cholera patients in Calcutta.Out of 1562 diarrhoeal stool samples, Vibrio cholerae was isolated in 266 cases. Stool samples obtained were examined microscopically within two hours of collection. RBCs and faecal leucocytes were examined by normal saline and methylene blue stain. Stool culture was performed using selective and differential media for isolation of V. cholerae.Among 266 cholera patients, RBCs was detected in 58 per cent and faecal leucocytes in 88 per cent respectively. The extent of the changes correlated with clinical severity.This study showed the presence of RBCs and faecal leucocytes in stools of patients of cholera caused by V. cholerae 01 and 0139 which indicates some inflammatory changes in the gut mucosa. Further study is required to elucidate the inflammatory mechanism involved in the underlying process(es).

The presence of HIV-1 antibodies was determined among the injecting drug users (IDUs) and their non-injecting wives. A total of 233 (72%) were found to be HIV-1 seropositive among the 322 subjects recruited in this study between August, 1996 and September, 1997. The distribution of HIV-1 subtypes among the injecting drug users (IDUs) and their wives was determined using peptide enzyme immunoassay (EIA). Sexual transmission of HIV-1 occurred frequently (45%) from HIV-1 infected IDUs to their spouses. The majority of the subjects (167/233) were infected with subtype C followed by subtype Thai B (29/233). Subtype C was the most common among both IDUs (78%) and their wives (57%), followed by subtype Thai B (12% and 13% respectively). The distribution of subtypes was significantly different between IDUs and their wives with a lower percentage of subtype C and higher percentage of subtype D in the infected wives (P0.03). Discordance for subtypes transmitted from IDUs to their wives suggests the occurrence of dual and/or recombinant infection in the IDUs.

Hepatitis C virus (HCV) and hepatitis B virus (HBV) infections were evaluated among 77 Manipuri couples of whom all husbands were both intravenous drug users (IDUs) and human immunodeficiency virus (HIV) positive. This study showed for the first time a high prevalence of HCV (92%) and HBV (100%) infection amongst the IDUs in Manipur. Stringent control measures to prevent the transmission of hepatitis viruses (B and C) are urgently required in Manipur.

The prevalence of different serotypes of non-typhoidal Salmonella spp. among patients suffering from acute diarrhoea admitted to the Infectious Diseases Hospital, Calcutta was investigated. The predominant serogroup was C and Salmonella infantis was the major serotype isolated followed by S. worthington, S. enteritidis, S. typhimurium, S. weltevereden and S. newport. All the Salmonella strains were isolated from adults. Multidrug resistance to various antimicrobial agents was observed in 37.5 per cent of the strains. All the strains were sensitive to ciprofloxacin, norfloxacin and gentamycin.

From October to December 1998, single faecal samples from 67 healthy cattle in a semi-urban community near Calcutta were examined for Shiga toxin producing Esch. coli (STEC) using a multiplex PCR primary screen followed by plating on sorbitol MacConkey agar. STEC was isolated from the faeces of 7 (10.5%) animals. The eight strains isolated belonged to eight serotypes viz, O146:H1, O149:HNT, ONT:H34, ONT:H19, O88:HN, ONT:H2, O82:H8 and O28ac:H21. Bead enzyme linked immunosorbent assay showed that three strains produced Shiga toxin 1, one produced Shiga toxin 2 and four produced both.

We examined the clonal relationships among eight clinical isolates of non-toxigenic (NT) V. cholerae O1 associated with a cluster of cases of cholera in Warangal, Andhra Pradesh in south India and compared their relatedness to toxigenic O1 strains of classical and E1Tor biotypes and with O139 Bengal strains of V. cholerae by pulsed-field gel electrophoresis (PFGE). Phylogentic analysis of the NotI restriction fragment length polymorphism showed that all the NT. V. cholerae O1 strains formed a tight cluster with more than 80 per cent similarity. Interestingly, the NT V. cholerae O1 cluster was more closely related to V. cholerae O139 than to classical and E1Tor biotypes of V. cholerae O1 indicating closer genetic relationships between NT V. cholerae 01 and O139 Bengal strains that were isolated during the same time-frame.

Study on a cohort of injecting drug users (n = 76) was initiated in June, 1994 with the objective of documenting the clinical presentation of HIV and its progression with time. The participation in the study was voluntary. An informed consent was taken from the subjects before they were enrolled in the study. The subjects were followed up every 45 days for clinical and laboratory examination and analysis made after 27 months of the study. The study had a follow-up rate of 65 per cent. The commonest feature observed in stage I (n = 47) was persistent generalized lymphadenopathy (83%), in stage II (n = 40) was body weight loss10 per cent (37.5%), in stage III (n = 32) was pulmonary tuberculosis (56.3%) and in stage IV (n = 9) was cryptosporidial diarrhoea1 month (3 cases). Kaposi's sarcoma was detected in one subject. The median time taken for conversion from the date of seroconversion to stage III of HIV infection was observed to be 3.15 yr (95% CI = 2.98-3.58 yr). The rate of HIV progression seems to be significantly faster than that observed in industrialized countries. Age is a cofactor in the rate of progression of HIV. Tuberculosis is the commonest opportunistic infection.

Glucose-based or rice-based ORS is the standard treatment in acute dehydrating diarrhoea. However, glucose may not be easily available in remote villages and the rice needs to be cooked for rice-based ORS. We embarked on a study to examine whether uncooked rice powder could be used as an alternative to glucose or cooked rice powder in ORS. Initially, 50 adult male patients (aged 18 to 55 yr) were randomized to receive glucose-ORS or uncooked rice ORS, in two equal groups. Subsequently, 20 male children (aged 3 to 12 yr) were also enrolled in the study and received either WHO-ORS or study ORS. All the adult patients and the children could be successfully rehydrated with ORS containing uncooked rice powder. As compared to WHO-ORS, the study ORS significantly reduced stool output (6.60 +/- 1.24 vs. 5.88 +/- 1.34 l), ORS intake (9.17 +/- 1.54 vs 8.24 +/- 1.69 l) and duration of diarrhoea (45.68 +/- 6.91 vs 41.32 +/- 6.03 h). In children also similar results were obtained. No clinical complication (e.g., vomiting, abdominal pain etc.) or abnormality in serum electrolyte concentrations was encountered either in the adults or in the children. Uncooked rice powder containing ORS can be considered as an alternative to glucose-based ORS or rice-based ORS.

Fourteen strains of Shigella spp. were isolated from patients aged 5-12 yr, hospitalized with dysentery during 1995-1996. The strains isolated were Shigella dysenteriae 1, S. flexneri and S.sonnei. All but one of the 14 strains were sensitive to ciprofloxacin and norfloxacin. The MIC of both the fluoroquinolones was 15 micrograms/ml for the resistant S.dysenteriae 1 strain (NRM4). Therefore, the careful use of antimicrobials is required for therapy of Shigellosis.

An attempt was made to isolate Clostridium difficile from 129 faecal specimens from 87 young and 42 elderly healthy adults. C.difficile was isolated using bacterial culture from 7 (5.4%) specimens and the frequency of isolation of toxigenic C. difficile as detected by cytotoxin (tissue culture) assay was 1.1 per cent and 2.4 per cent in healthy young and elderly adults respectively. The carrier rate of toxigenic C. difficile amongst healthy adults is relatively low in this part of our country.

In May 1996, a massive outbreak of cholera occurred in Alleppey district of Kerala which spread to Palghat district by July 1996. Of the 575 patients hospitalized at the Alleppey Medical College hospital between May 1 and August 2, 1996, 30 deaths occurred with a case fatality rate of 5.2 per cent while of the 638 diarrhoea patients admitted at Agali PHC of Attapadi area in Palghat district, 30 (4.7%) deaths were recorded. Clinically, the patients had profuse watery diarrhoea with vomiting. The epidemic of cholera in Alleppey and Palghat districts was caused by V. cholerae O1 of the EITor biotype, Ogawa serotype which possessed both the ctxA and tcpA genes when examined by multiplex PCR. Gross contamination of water sources was incriminated as the cause of the epidemic.

This study reports the bactericidal activity of potash alum when added to water, against various epidemic causing enteric pathogens like Vibrio cholerae 01, V. cholerae 0139 and Shigella dysenteriae 1 by lowering the pH of water (from 6.0 to 4.0). Growth of the enteric pathogens was monitored in vitro by inoculating broth cultures of the different organisms in distilled water containing increasing concentrations of potash alum and quantitatively determining the concentration of viable organisms over a 48 h period by the standard plate count method. Controls constituted cultures of each organism grown in the absence of potash alum. The pH of alum administered water was measured in each test tube before inoculation of organisms. Potash alum was found to inhibit growth (10(5) viable count per ml) of most of the organisms examined, particularly V. cholerae 01 and V. cholerae 0139 in a dose dependent fashion. Reduction of colony forming units was observed in presence of 0.25 g/dl of alum after 5 h and no growth was noticed after 24 h.

Various culture media [AKI, Brain heart infusion broth (BHI), Casamino acid-yeast extract broth (CAYE), Casamino acid-yeast extract broth supplemented with 90 micrograms/ml of lincomycin (CAYE-L), Tryptic soy broth (TSB) and Yeast extract peptone (YEP)], cultural conditions (stationary and shaking) and incubation temperatures (30 degrees C and 37 degrees C) were evaluated to determine optimal conditions for production of cholera toxin (CT) by different biotypes (classical and E1Tor) and serogroups (O1 and O139) of V. cholerae. It was found that V. cholerae O1 E1Tor grown in CAYE-L and incubated at 30 degrees C with constant shaking was optimal for production of CT, while for the classical biotype and for the O139 serogroup, CT was maximally produced when grown in YEP and incubated at 30 degrees C in a shaker. Temperature appeared to be a prominent factor affecting the production of CT by the O1 E1Tor biotype when the media used were AKI, CAYE-L and YEP and also for the classical biotype when the media used were the AKI, BHI, CAYE and YEP. In the case of the O1 E1Tor biotype, CAYE-L was the best medium for CT production whereas for the classical biotype, CAYE-L was a poor medium as far as CT production was concerned. Irrespective of the media used, 30 degrees C shake culture condition seemed to be more favourable for supporting CT production except in CAYE medium for the O1 E1Tor biotype where incubation at 37 degrees C in a shaker was as good as incubation at 30 degrees C.

Acute diarrhoeal diseases are an important cause of morbidity and mortality, particularly in children. Acute diarrhoea may be watery, where features of dehydration are more prominent or dysenteric, where the stools contain blood and mucous. Rehydration therapy is the key to the management of acute watery diarrhoea, whereas antibiotics play a vital role in the management of acute invasive diarrhoea, particularly shigellosis. Rehydration may be done either by the oral or intravenous routes depending upon the degree of dehydration. Oral rehydration salt solution of WHO formula is recommended for oral rehydration therapy (ORT). Ringer's lactate is the ideal intravenous fluid for correction of severe dehydration due to diarrhoea. Antibiotic therapy is beneficial for cholera and shigellosis only. Antiparasitic agents are indicated only if amoebiasis or giardiasis is present. Antidiarrhoeals are of no benefit for the treatment of acute diarrhoea. Appropriate feeding during diarrhoea is recommended with beneficial outcome.

This study was conducted to examine whether substitution of polyclonal anti-CT IgG (PAb) coated beads with monoclonal anti-CT IgG, (MAb) coated beads would enhance the sensitivity and specificity of the Bead ELISA for direct detection of CT in stool samples of cholera patients. Sensitivity of MAb Bead ELISA was found to be more efficient (92.7%) than the PAb Bead ELISA (88.2%) in comparison to the 'gold standard' method of conventional culture method (CM). However, the MAb based Bead ELISA had lower specificity (45%) than that of PAb Bead ELISA (51.8%). Further, the positive predictive value was also lower in MAb Bead ELISA (69.9%) as compared to PAb Bead ELISA (82.1%). Generally, all the statistical evaluation demonstrated better agreement between PAb (77.9%) and MAb (72.6%) Bead ELISAs in direct detection of free CT and culture method in confirming the causative organism i.e., Vibrio cholerae in stool specimens. When the two assay systems, viz., PAb and MAb Bead ELISAs were compared, the superiority of the PAb Bead ELISA over MAb Bead ELISA was clearly evident as it had 82.4 per cent of agreement value.

A genetic epidemiological study of serum lipid and lipoprotein levels was conducted among families of Marwaris residents in Calcutta. A total of 210 families, comprising over 100 individuals, were studied. Analyses were performed to estimate the genetic and environmental effects on the determination of high density lipoprotein cholesterol (HDL-C) and serum triglycerides (TG). Familial correlations for HDL-C and TG were estimated: parent-child and sib-sib correlations were found to be significant. Spouse correlations were not significant. Correlations between environments of siblings were significant. Genetic analysis of data on HDL-C and TG performed under a path model, taking genetic transmission and possible environmental associations among family members into account, indicated that lipid and lipoprotein levels adjusted and standardized for age, gender, education, occupation and disease status are primarily determined by genetic factors. The effects of environmental factors were also significant, although in comparison with genetic factors these effects were much smaller. The estimated genetic heritability for HDL-C was approximately 80 per cent, while that for TG was approximately 55 per cent. The genetic effects and environmental effects were not significantly different between adults and children.

As one of large outbreaks of cholera-like illness in the Indian subcontinent, Calcutta and its neighbouring areas experienced an unprecedented epidemic due to a new strain of V. cholerae non-01, designated as V. cholerae 0139 Bengal, since January 1993. This epidemic predominantly affected the adult population of Calcutta as evidenced by the hospitalization of more adults at the Infectious Disease Hospital, Calcutta (IDH), which bore the main brunt of the epidemic in and around Calcutta. During the peak of the epidemic about 180 to 300 diarrhoea patients were admitted daily at the IDH. Of the 807 patients screened, 407 were positive for V. cholerae 0139 and majority (82.8%) of the cases were10 yr of age. Severe dehydration was recorded in 85.5 per cent of the cases.

Results of a single Widal test in patients with bacteriologically confirmed typhoid fever (116), clinically suggestive but culture negative fever (170) and non-typhoidal febrile illness (98) and in normal control children (54) were analysed. Positive Widal test (antibody titre against S. typhi O antigen of 1:160) was recorded in 61.2 per cent of patients with bacteriologically confirmed typhoid fever and in 58.8 per cent with culture negative but clinically suggestive typhoid fever. In contrast, the same titre was observed in 10.2 per cent patients with other febrile illnesses of known etiology and in 1.8 per cent of normal children. Differences in the positivity of Widal test in patients with bacteriologically confirmed typhoid fever and clinically suggestive but culture negative fever were highly significant (P0.000001) when compared to that of patients with non-typhoidal febrile illnesses and normal controls. High specificity and positive predictive value in 1:160 dilution makes the Widal test acceptable as a diagnostic tool.

Blood and faecal samples were collected from 122 hospitalised patients of Calcútta clinically suspected to have enteric fever, for isolation of S. typhi. It was isolated from 34.4, 4.9 and 4.1 per cent patients by blood culture, stool culture and by both respectively. The in vitro drug susceptibility testing showed that all the isolates were resistant to chloramphenicol, ampicillin and trimethoprim-sulphamethoxazole, but were uniformly susceptible to ciprofloxacin, norfloxacin and furazolidone. In view of the appearance of multi-drug resistant S. typhi in Calcutta, great care should be exercised in the use of newer quinolone derivatives.

Characteristics of V. cholerae isolated from patients of acute secretory diarrhoea admitted to the Infectious Diseases Hospital, Calcutta during two consecutive cholera seasons (1989 and 1990), with special emphasis on biotyping and toxigenicity, were investigated. The isolation rates of V. cholerae during 1989 and 1990 were 78 and 85.1 per cent respectively, with Inaba serotype dominating in 1989 and Ogawa in 1990. All the V. cholerae 01 strains isolated in this study belonged to biotype Eltor with phage type 4 dominating (48.8%). Most of the strains of V. cholerae were resistant to 10 and 150 micrograms/ml of 0/129 vibriostatic agent. Similarly, majority of the V. cholerae strains were resistant to furazolidone (95.7%), cotrimoxazole (83%) and tetracycline (63.1%) and several resistance patterns were encountered. All the V. cholerae 01 strains examined produced cholera toxin (CT) in amounts ranging between greater than 70 pg/ml and greater than 2.5 ng/ml. In contrast, all but one of the non-01 strains isolated in this study did not produce CT. Further studies are required to elucidate the mechanism involved in the pathogenesis of non-01 V. cholerae mediated diarrhoea.