Novel role of cardiovascular MRI to contextualise tuberculous pericardial inflammation and oedema as predictors of constrictive pericarditis

Tuberculosis (TB) and human immunodeficiency virus/acquired immunodeficiency syndrome have reached epidemic proportions, particularly affecting vulnerable populations in low- and middle-income countries of sub-Saharan Africa. TB pericarditis is the commonest cardiac manifestation of TB and is the leading cause of constrictive pericarditis, a reversible (by surgical pericardiectomy) cause of diastolic heart failure in endemic areas. Unpacking the complex mechanisms underpinning constrictive haemodynamics in TB pericarditis has proven challenging, leaving various basic and clinical research questions unanswered. Subsequently, risk stratification strategies for constrictive outcomes have remained unsatisfactory. Unique pericardial tissue characteristics, as identified on cardiovascular magnetic resonance imaging, enable us to stage and quantify pericardial inflammation and may assist in identifying patients at higher risk of tissue remodelling and pericardial constriction, as well as predict the degree of disease reversibility, tailor medical therapy, and determine the ideal timing for surgical pericardiectomy.

Issues in Medicine

Rasmussen aneurysms are abnormalities of the pulmonary arterial system caused by tuberculosis (TB). They are associated with a highmortality rate when they cause life-threatening haemoptysis. High TB-prevalence regions have a large burden of TB-related haemoptysisbut often limited resources. This series of 25 patients who presented with life-threatening haemoptysis from current and/or previous TBwere found to have abnormal pulmonary arteries on computed tomography pulmonary angiogram (CTPA), which were judged to belikely contributors to their bleeding, either in isolation or with concomitant abnormal bronchial or systemic vasculature. These patientsunderwent transcatheter placement of Amplatzer vascular plugs in the feeder pulmonary artery. Bronchial and systemic lesions wereaddressed separately as needed. Immediate technical success was achieved in all patients, but four of them experienced intraoperativehaemoptysis related to dislodgement of the occluding platelet plug by the high-pressure automatic injector and wire. At 48 hours after theprocedure, 18 (72%) remained haemoptysis-free. Six of these experienced recurrence within 1 year of their procedure. Pulmonary arteryplacement of an Amplatzer vascular plug is a feasible option for treating bleeding Rasmussen aneurysms, but should be part of a combinedapproach to addressing suspected culprit vascular lesions in all intrathoracic vascular systems.

SLE pachymeningitis and multiple cranial nerve palsies: a case report and review of the literature

Hypertrophic pachymeningitis (HP) is a relatively uncommon disease associated with focal or diffuse thickening of the dura mater secondary to underlying chronic inflammation. The link between systemic lupus erythematosus (SLE) and hypertrophic pachymeningitis (HP) is extremely rare, with only six other cases reported in the literature. We, however, report the first case of SLE pachymeningitis presenting with multiple cranial nerve palsies. The patient showed good response to steroids and cyclophosphamide therapy. One should maintain a high index of suspicion to make the diagnosis in patients with SLE presenting with neurological dysfunction. Prompt therapy prevents long-term neurological sequelae.

50 years of tuberculosis control in India: progress, pitfalls and the way forward

India established the National Tuberculosis Control Project (NTCP) 50 years ago and re-designed it as Revised NTCP (RNTCP) 19 years ago. Tuberculosis (TB) control was beset with obstacles-BCG vaccination was found ineffective in TB control in 1979; human immunodeficiency virus began spreading in India since 1984 with TB as the commonest opportunistic disease; multi-drug resistance was found to be prevalent since 1992. The World Health Organization declared TB as global emergency in 1993. Yet, RNTCP was extended to the whole nation very slowly, taking 13 years from inception. The first objective of RNTCP, namely 85% treatment success has been achieved and case-fatality had dropped by 90%;. Still, TB burden continues to remain huge; about half the cases are not getting registered under RNTCP; pediatric TB is neglected; TB drains national economy of US$ 23 billion annually. Therefore, TB control is in urgent need of re-design and re-invigoration, with additional inputs and system re-organization to cover all such gaps. We highlight the need for Public Health infrastructure under which all vertical disease control projects such as RNTCP should be synergized for better efficiency and for establishing Public Health Surveillance for collecting denominator-based data on incidence and prevalence to guide course corrections. India ought to spend 3 to 5 times more on TB control than at present. Control needs clear epidemiologic definition and measurable parameters for monitoring the level of control over time. TB control is both a measure of, and a means to, socioeconomic development.

Building on the success of the Expanded Programme on Immunization: enhancing the focus on disease prevention and control

The Expanded Programme on Immunization (EPI) has succeeded in establishing a vaccine delivery system in all low and middle income (LMI) countries. Because EPI has focused on immunization delivery, its major outcome is measured in many countries only as vaccine coverage, not as disease reduction, the real goal of EPI. Monitoring disease reduction requires real-time case-based disease surveillance and appropriate interventions, for which a functional public health infrastructure is needed. If the highest priority for assessing impact of EPI shifts to disease prevention and control from vaccine coverage, the programme may be transformed to one of control of childhood communicable diseases (CCCD), with the potential of expanding the range of diseases of children and adults for control and of integrating all other current vertical (single disease) control efforts with it. EPI provides the essential platform on which CCCD can be built to create a public health infrastructure.

Clinical & pathological features of acute toxicity due to Cassia occidentalis in vertebrates

Cassia occidentalis is an annual shrub found in many countries including India. Although bovines and ovines do not eat it, parts of the plant are used in some traditional herbal medicines. Several animal studies have documented that fresh or dried beans are toxic. Ingestion of large amounts by grazing animals has caused serious illness and death. The toxic effects in large animals, rodents and chicken are on skeletal muscles, liver, kidney and heart. The predominant systems involved depend upon the animal species and the dose of the beans consumed. Brain functions are often affected. Gross lesions at necropsy consist of necrosis of skeletal muscle fibres and hepatic centrilobular necrosis; renal tubular necrosis is less frequent. Muscle and liver cell necrosis is reflected in biochemical abnormalities. The median lethal dose (LD(50)) is 1 g/kg for mice and rats. Toxicity is attributed to various anthraquinones and their derivatives and alkaloids, but the specific toxins have not been identified. Data on human toxicity are extremely scarce. This review summarizes information available on Cassia toxicity in animals and compares it with toxic features reported in children. The clinical spectrum and histopathology of C. occidentalis poisoning in children resemble those of animal toxicity, affecting mainly hepatic, skeletal muscle and brain tissues. The case-fatality rate in acute severe poisoning is 75-80 per cent in children.

Vaccination greatly reduces disease, disability, death and inequity worldwide

In low-income countries, infectious diseases still account for a large proportion of deaths, highlighting health inequities largely caused by economic differences. Vaccination can cut health-care costs and reduce these inequities. Disease control, elimination or eradication can save billions of US dollars for communities and countries. Vaccines have lowered the incidence of hepatocellular carcinoma and will control cervical cancer. Travellers can be protected against "exotic" diseases by appropriate vaccination. Vaccines are considered indispensable against bioterrorism. They can combat resistance to antibiotics in some pathogens. Noncommunicable diseases, such as ischaemic heart disease, could also be reduced by influenza vaccination. Immunization programmes have improved the primary care infrastructure in developing countries, lowered mortality in childhood and empowered women to better plan their families, with consequent health, social and economic benefits. Vaccination helps economic growth everywhere, because of lower morbidity and mortality. The annual return on investment in vaccination has been calculated to be between 12% and 18%. Vaccination leads to increased life expectancy. Long healthy lives are now recognized as a prerequisite for wealth, and wealth promotes health. Vaccines are thus efficient tools to reduce disparities in wealth and inequities in health.

Vaccination greatly reduces disease, disability, death and inequity worldwide

In low-income countries, infectious diseases still account for a large proportion of deaths, highlighting health inequities largely caused by economic differences. Vaccination can cut health-care costs and reduce these inequities. Disease control, elimination or eradication can save billions of US dollars for communities and countries. Vaccines have lowered the incidence of hepatocellular carcinoma and will control cervical cancer. Travellers can be protected against "exotic" diseases by appropriate vaccination. Vaccines are considered indispensable against bioterrorism. They can combat resistance to antibiotics in some pathogens. Noncommunicable diseases, such as ischaemic heart disease, could also be reduced by influenza vaccination. Immunization programmes have improved the primary care infrastructure in developing countries, lowered mortality in childhood and empowered women to better plan their families, with consequent health, social and economic benefits. Vaccination helps economic growth everywhere, because of lower morbidity and mortality. The annual return on investment in vaccination has been calculated to be between 12% and 18%. Vaccination leads to increased life expectancy. Long healthy lives are now recognized as a prerequisite for wealth, and wealth promotes health. Vaccines are thus efficient tools to reduce disparities in wealth and inequities in health.

The prevention and control of human leptospirosis

Human leptospirosis is prevalent in several states in India, sporadically or as outbreaks, especially during rainy seasons. It affects predominantly male adults who work in agriculture, causing severe morbidity and unnecessary mortality. Yet, there is no systematic leptospirosis prevention and control programme in the country, as it is not identified as priority under the national health policy. Therefore states with leptospirosis ought to establish public health programme for its prevention and control, as part of building a comprehensive initiative for the control of all-important infectious diseases. After establishing disease surveillance and laboratory support service, the disease burden must be monitored before and during interventions for control. The District is the ideal unit of activity, with full participation of the State Government and Local Panchayati raj. The public health staff must give technical leadership and the risk factors of human leptospirosis must be identified and specific interventions targeted against them. Action must be local-area-specific and coordinated between the Departments of Health, Agriculture, Animal Husbandry, Environment and Forestry. A model leptospirosis control programme has been formulated in Kerala State and is awaiting implementation. A state level Diagnostic and Epidemiology centre has been established to provide technical leadership. This model must be implemented and also replicated in other states. The most important ingredient for the control of infectious diseases is the 'political will'.

Anomalous observations on IPV and OPV vaccination

Anomalies of vaccine performance are events or observations that go counter to the current paradigms on the properties of a vaccine. In the current paradigm, inactivated poliovirus vaccine (IPV) induces serum immunity to protect the individual from poliomyelitis, but not mucosal immunity to prevent subsequent wild poliovirus infection. Therefore, it is believed not to be suitable to interrupt virus transmission in polio-endemic tropical and developing countries, where poliovirus transmission is thought to be predominantly faecal-oral, unlike in countries with excellent sanitation, where it is predominantly respiratory. Oral poliovirus vaccine (OPV), because it is believed to mimic natural (wild) poliovirus infection and to induce serum and mucosal immunity, is considered ideal to interrupt virus transmission in countries with poor sanitation and endemic polio. Moreover, the vaccine viruses are shed in the stools and it is presumed to spread faeco-orally to unvaccinated children in the vicinity, thus increasing its effectiveness in the community. These paradigms on both vaccines may be seen in standard textbooks of virology and paediatrics. In reality, IPV induces very high mucosal immunity in a monkey model, lasting at least 12 months and providing complete protection against oral challenge with wild virus. In field trials, IPV has been found to have very high vaccine efficacy (VE) and to retard significantly wild-virus transmission in communities. OPV, requiring five to seven doses for individual protection, does not seem to induce effective mucosal immunity. Hence, 10-15 doses of OPV and near 100% vaccination coverage are necessary for interruption of virus transmission in countries with poor sanitation. In the monkey model, wild poliovirus infection did not offer any mucosal protection against a second infection, indicating that live virus infection is not the best way to induce mucosal immunity (unless repeated several times). The immunity induced by OPV has two arms, individual protection (by serum immunity) and mucosal protection from later infection by wild virus; these are dichotomous, as evidenced further by protected children participating in wild virus transmission in breakthrough outbreaks in communities well vaccinated with OPV. There is no evidence that polioviruses, wild or vaccine, spread faeco-orally to any meaningful extent. The median age of polio in India, in the pre-vaccine era, and even in recent years was 12-18 months. No other faeco-oral infection has such a low median age. Measles virus transmission is respiratory, and the median age of measles is over two years. Wild virus is shed faecally, but by the age when faecal microbes infect children, most of them are already immune to disease caused by polioviruses. As for vaccine viruses, even when heavy inocula are fed repeatedly, children may not always become infected. That exposure to the small amounts of virus through faecal contamination (unlike microbes that multiply in food) would infect them, is an unrealistic expectation. There are sufficient anomalies demanding our revision of the old paradigms. IPV is a better immunogen than OPV and is completely safe. During the interval between the cessation of wild virus transmission and the global stoppage of polio vaccination, it will be advantageous to use IPV, particularly combined with DPT vaccine, to provide individual protection, and herd effect to prevent spread in case of the introduction of wild polioviruses, whether unintentionally or otherwise, and to bolster the Expanded Programme on Immunisation.

Herd immunity and herd effect: new insights and definitions

The term herd immunity has been used by various authors to conform to different definitions. Earlier this situation had been identified but not corrected. We propose that it should have precise meaning for which purpose a new definition is offered: "the proportion of subjects with immunity in a given population". This definition dissociates herd immunity from the indirect protection observed in the unimmunised segment of a population in which a large proportion is immunised, for which the term 'herd effect' is proposed. It is defined as: "the reduction of infection or disease in the unimmunised segment as a result of immunising a proportion of the population". Herd immunity can be measured by testing a sample of the population for the presence of the chosen immune parameter. Herd effect can be measured by quantifying the decline in incidence in the unimmunised segment of a population in which an immunisation programme is instituted. Herd immunity applies to immunisation or infection, human to human transmitted or otherwise. On the other hand, herd effect applies to immunisation or other health interventions which reduce the probability of transmission, confined to infections transmitted human to human, directly or via vector. The induced herd immunity of a given vaccine exhibits geographic variation as it depends upon coverage and efficacy of the vaccine, both of which can vary geographically. Herd effect is determined by herd immunity as well as the force of transmission of the corresponding infection. Clear understanding of these phenomena and their relationships will help improve the design of effective and efficient immunisation programmes aimed at control, elimination or eradication of vaccine preventable infectious diseases.

Should health care workers in the tropics be immunized against varicella?

In tropical regions, chickenpox affects both adults and children. Therefore, healthcare workers in the tropics are vulnerable to hospital-acquired varicella infection and they may transmit infection to susceptible hospitalized individuals. Although the varicella vaccine is safe and effective, its cost is a deterrent to its use in routine immunization programmes. In order to assess whether vaccination of susceptible healthcare workers to prevent hospital-acquired transmission may be justified, we have documented the frequency of varicella among healthcare workers in our hospital. There were 96 admissions for varicella during the 1993-1997 period; staff and student nurses accounted for 76%. The peak season of admission was from February to April. The attack rate in staff and student nurses was 0.78 and 1.54 per 100 person-years, respectively. While community outbreaks of varicella occur in this region once in 4-5 years, hospital outbreaks of varicella occurred every year. This poses the risk of transmission to hospitalized patients, with serious consequences among immunocompromized individuals. Therefore, we recommend systematic selective vaccination of susceptible healthcare workers to break this cycle of annual varicella outbreaks among hospital personnel.

Comparison of different culture media and storage temperatures for the long-term preservation of Streptococcus pneumoniae in the tropics

OBJECTIVE

The preservation of Streptococcus pneumoniae by standard freezing methods for subsequent tests--such as serotyping and antibiotic susceptibility--is not possible or is difficult in many developing countries because of the high cost of equipment, inadequate equipment maintenance, and irregular power supply. We evaluated alternative low-cost methods, by comparing different culture media and storage temperatures.

METHODS

Clinical isolates of five capsular types (1, 5, 7, 19, and 23) of S. pneumoniae were preserved in rabbit blood, sheep blood, skimmed milk, or glycerol-chocolate broth, and stored at -20 degrees C or -70 degrees C. The cultures were also preserved by lyophilization or sand desiccation, followed by storage at room temperature and 4 degrees C. The viability of the preserved cultures was determined by making serial colony counts on day 0 and after 1 week, 4 weeks, 4 months and 16 months. The viability of cultures preserved by sand desiccation and storage at 4 degrees C was also determined every 6 months for up to 68 months.

FINDINGS

Irrespective of the media used, cultures maintained at -20 degrees C became nonviable by the fourth month, while those maintained at -70 degrees C were still viable at 16 months. Cultures preserved by lyophilization or sand desiccation lost their viability by the fourth month when maintained at local room temperature (30-42 degrees C), but remained viable when stored at 4 degrees C for up to 68 months.

CONCLUSIONS

Our results confirm that freezing at -70 degrees C, or lyophilization and storage at 4 degrees C are the ideal methods for the preservation of S. pneumoniae. In laboratories where lyophilization is not feasible, sand desiccation and storage at 4 degrees C offers an alternative low-cost method for the long-term preservation of S. pneumoniae.

Vaccinia reactive antibodies in a south Indian population

The prevalence of vaccinia virus antibodies was determined in both urban and rural populations in southern India. The study sample consisted of 211 adults and 52 children. The antibody titre was measured in all sera by virus neutralisation and by indirect immunofluorescence assay (IFA). A small panel of sera was tested by Western blotting. There was no significant difference in detection rates between the tests. Generally, seropositivity correlated with a previous history of vaccination. All children were negative for vaccinia antibodies. Among adults overall, 54% had neutralising antibodies whereas 60% were positive for antibodies detected by IFA, however, the prevalence of vaccinia antibody by either method was significantly higher (P < 0.001) among rural subjects than in urban subjects. This higher antibody prevalence among the rural population could be due to exposure to other indigenous orthopoxviruses, possibly buffalopox.

Increase in plasma IL-10 levels and rapid loss of CD4+ T cells among HIV-infected individuals in south India

Increased levels of immune activation among HIV patients from developing countries are believed to accelerate and/or enhance the shift to a Th2 cytokine environment, which in turn may result in a more rapid progression to AIDS. In support of this hypothesis, we present data from a cohort of 35 HIV+ individuals in southern India. Among asymptomatic individuals in this cohort, a dramatic increase in plasma interleukin (IL)-10 coincided with rapid decrease in CD4 counts and progression to AIDS. Serum IL-10 levels were significantly higher after 6 months of follow up (P=0.01), while CD4 counts declined at a rate of 280 cells/ul per year, roughly 3 times the rate of decline reported for HIV+ asymptomatic subjects in developed countries. Changes in serum IL-10 levels and CD4 counts fell short of statistically significant correlation (P=0.1). Among AIDS patients in this cohort, the mean period from diagnosis of AIDS to death was <5 months and is in agreement with an earlier report of rapid progression in India.