Public health, preparedness and the World Health Organization response to swine flu in 2009

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HPV vaccines: separating real hope from drug company hype

Rothman SM, Rothman DJ. Marketing HPV vaccine. Implications for adolescent health and medical professionalism

Making can-do into must-do: the way forward to health and wealth?

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Burden of disease & molecular epidemiology of group A rotavirus infections in India

Rotavirus is the major cause of severe dehydrating diarrhoea in young children worldwide. Considerable research has been carried out on rotavirus disease in India. This review collated data from 46 epidemiological studies to determine rotavirus positivity rates and genotypes of infecting rotavirus strains from various settings in India. Studies on diarrhoea presenting to hospitals, neonatal rotavirus infections, symptomatic and asymptomatic infections in the community and nosocomial enteric infections were included. Rotavirus positivity rates varied greatly between different settings - diarrhoea hospitalizations (20%), neonatal infections (35%), symptomatic and asymptomatic infections in the community (15.1% and 6.3% respectively) and nosocomial enteric infections (22.5%). Among diarrhea hospitalizations, the commonest G types were G1 and G2 while commonest P types were P[8], P[6] and P[4]. Region specific neonatal infections by bovinehuman reassortants have been reported, in addition to several recently described unusual strains, which may be evidence of zoonotic infection and/or reassortment. The emergence of several new strains highlights the need for intensive strain surveillance before and after the introduction of a new vaccine

We have company: how gut bacteria influence, health and disease

Discoveries made in the last five years or so have shown that we are introduced to micro- organisms even before our birth. Contrary to earlier belief that the mother’s womb protects a developing foetus against micro-organisms, we now know that bacteria from the mother’s blood can enter the amniotic fluid (that surrounds the developing foetus). The type and numbers of these bacteria have a huge bearing not only on pregnancy outcomes but also on the immune system of the new-born. Our association with microbes becomes more rapid at the time of our birth. A new-born is exposed to micro- organisms in almost everything it makes contact with – its mother’s birth canal, skin and breast-milk; other food; and the environment. All its exposed surfaces, including its skin, eyes, ears, reproductive tract and gut, are quickly colonised by microbes. The nature and size of these initial microbial populations can vary initially with changes in diet and environment, but as a child grows older, these microbial communities become more stable in composition. The gut of an adult has over thousands of species of micro-organisms of all kinds – bacteria, fungi and viruses, and contributes nearly 2 kilograms of her body weight

Rotavirus seasonality and age effects in a birth cohort study of southern India

Introduction: Understanding the temporal patterns in disease occurrence is valuable for formulating effective disease preventive programs. Cohort studies present a unique opportunity to explore complex interactions associated with emergence of seasonal patterns of infectious diseases. Methods: We used data from 452 children participating in a birth cohort study to assess the seasonal patterns of rotavirus diarrhea by creating a weekly time series of rotavirus incidence and fitting a Poisson harmonic regression with biannual peaks. Age and cohort effects were adjusted for by including the weekly counts of number of children in the study and the median age of cohort in a given week. Weekly average temperature, humidity and an interaction term to reflect the joint effect of temperature and humidity were included to consider the effects of meteorological variables. Results: In the overall rotavirus time series, two significant peaks within a single year were observed – one in winter and the other in summer. The effect of age was found to be the most significant contributor for rotavirus incidence, showing a strong negative association. Seasonality remained a significant factor, even after adjusting for meteorological parameters, and the age and cohort effects. Conclusions: The methodology for assessing seasonality in cohort studies is not yet developed. This is the first attempt to explore seasonal patterns in a cohort study with a dynamic denominator and rapidly changing immune response on individual and group levels, and provides a highly promising approach for a better understanding of the seasonal patterns of infectious diseases, tracking emergence of pathogenic strains and evaluating the efficacy of intervention programs

Prevalence & risk factors for soil transmitted helminth infection among school children in south India

Background & objectives: Soil-transmitted helminths (STH) are a major public health problem in tropical and sub-tropical countries, affecting the physical growth and cognitive development in schoolage children. This study was aimed to assess the prevalence and risk factors of STH infection among school children aged 6-14 yr in Vellore and Thiruvanamalai districts in south India. Methods: Children aged 6-14 yr, going to government and government aided schools (n=33, randomly selected) in Vellore and Thiruvanamalai districts were screened to estimate the prevalence of STH, and a case control study was done on a subset to assess the risk factors for the infection. Results: The prevalence of STH was 7.8 per cent, varying widely in schools from 0 to 20.4 per cent, in 3706 screened children. Hookworm (8.4%) rates were high in rural areas, while Ascaris (3.3%) and Trichuris (2.2%) were more prevalent among urban children. Consumption of deworming tablets (OR=0.25, P<0.01) offered protection, while residing in a field hut (OR=6.73, P=0.02) and unhygienic practices like open air defaecation (OR=5.37, P<0.01), keeping untrimmed nails (OR=2.53, P=0.01) or eating food fallen on the ground (OR=2.52, P=0.01) were important risk factors for STH infection. Interpretation & conclusions: Our study indicated that school children with specific risk factors in the studied area were vulnerable subpopulation with elevated risk of STH infection. Identifying risk factors and dynamics of transmission in vulnerable groups can help to plan for effective prevention strategies

Molecular identification of hookworm isolates in humans, dogs and soil in a tribal area in Tamil Nadu, India

Background : Hookworms (Necator americanus and Ancylostoma duodenale) remain a major public health problem worldwide. Infections with hookworms (e.g., A. caninum, A. ceylanicum and A. braziliense) are also prevalent in dogs, but the role of dogs as a reservoir for zoonotic hookworm infections in humans needs to be further explored. Methodology/Principal Findings : As part of an open-label community based cluster-randomized trial in a tribal area in Tamil Nadu (India; 2013-2015), a total of 143 isolates of hookworm eggs from human stool were speciated based on a previously described PCR-RFLP methodology. The presence of hookworm DNA was confirmed in 119 of 143 human samples. N. americanus (100%) was the most prevalent species, followed by A. caninum (16.8%) and A. duodenale (8.4%). Because of the high prevalence of A. caninum in humans, dog samples were also collected to assess the prevalence of A. caninum in dogs. In 68 out of 77 canine stool samples the presence of hookworms was confirmed using PCR-RFLP. In dogs, both A. caninum (76.4%) and A. ceylanicum (27.9%) were identified. Additionally, to determine the contamination of soil with zoonotic hookworm larvae, topsoil was collected from defecating areas. Hookworm DNA was detected in 72 out of 78 soil samples that revealed presence of hook-worm-like nematode larvae. In soil, different hookworm species were identified, with animal hookworms being more prevalent (A. ceylanicum: 60.2%, A. caninum: 29.4%, A. duodenale: 16.6%, N. americanus: 1.4%, A. braziliense: 1.4%). Conclusions/Significance : In our study we regularly detected the presence of A. caninum DNA in the stool of humans. Whether this is the result of infection is currently unknown but it does warrant a closer look at dogs as a potential reservoir

Molecular epidemiology of rotavirus in children and animals and characterization of an unusual G10P[15] strain associated with bovine diarrhea in south India

AbstractRotaviruses are enteric pathogens causing acute, watery, dehydrating diarrhea in various host species, including birds and mammals. This study collected data on the disease burden and strain prevalence of Group A rotavirus in animals and humans in Vellore and investigated interspecies transmission by comparison of circulating genotypes. Stool samples from children aged less than 5 years, admitted to the hospital between January 2003 and May 2006 for diarrhea and diarrheal samples from animals that were collected from a veterinary clinic and several dairy farms near Vellore between February 2007 and May 2008 were processed and subjected to RNA extraction and reverse-transcription PCR for genotyping of VP7 and VP4. Of 394 children with diarrhea, 158 (40%) were positive for rotavirus and the common G types identified were G1 (47, 29.7%), G2 (43, 27.2%), G9 (22, 13.9%), G10 (2, 1.2%), G12 (1, 0.6%) and mixed infections (27, 17.8%). The common P types were P[4] accounting for 57 (36%) samples, P[8] 57 (36%), P[11] 3 (1.8%) and P[6] 2 (1.2%). Of 627 animals, 35 (1 bullock, 2 goats, 32 cows) were found to be infected with rotavirus (5.5%). The common G types identified in order of frequency were G6 (17, 48.5%), G2 (10, 28%), G10 (4, 11%), G8 (2, 5.7%) and mixed infections (2, 5.7%). The common P types were P[6] accounting for 16 (46%) samples, P[4] 7 (20%), P[1] 3 (8.5%) and P[8] 3 (8.5%). An unusual P type P[15] was seen in one sample in combination with G10. The finding of G2 infections which are rarely identified in animals implies anthroponotic transmission since this genotype is predominantly associated with infection in humans