Emergence and trends of penicillin non-susceptible Streptococcus pneumoniae in Saudi Arabia and Kuwait - perspective and outstanding issues

For many years in the past Streptococcus pneumoniae was uniformly susceptible to penicillin until the sudden and unexpected emergence of clinical infections caused by penicillin-resistant S. pneumoniae (PRSP) in 1967. Within the following decade, reports of nosocomial and community outbreaks of infections due to PRSP became widespread all over the world. Recent reports suggest that the incidence of resistance rates is rising in many countries although there are geographical variations in the prevalence and patterns of resistance between countries. The problem of antibiotic resistance is further compounded by the emergence of resistance to many beta-lactam antibiotics. The first report of PRSP in Saudi Arabia was in 1991. Barely a year after, PRSP infection was reported in Kuwait in 1992. Since then, studies from various parts of these countries have recorded prevalence rates ranging from 6.2% in Riyadh to 34% in Jeddah and 20% to 56% in neighboring Kuwait. These suggest considerable variation in the prevalence of PRSP in different cities in the Saudi Kingdom and Kuwait. The mechanism of resistance is due to chromosomally mediated alteration of penicillin-binding proteins (PBPs), which are target sites for beta-lactam antibiotics. It would appear that the spread of PRSP strains in Saudi Arabia is driven by the selective pressure created by excessive use and misuse of antimicrobial agents made possible by the easy availability of these agents, often frequently obtainable over the counter. In Kuwait, irrational and misguided use of antibiotics may be the major driving force favoring the spread of PRSP. The serotypes of strains encountered in Saudi Arabia and Kuwait are almost identical, with serotypes 19, 6, 15, 14 and 23 being the most common; together they constitute about 70% of the isolates circulating in these countries. In general, almost 90% of the serotypes included in the 23-polyvalent vaccine are present in the general population. However, a much lower percentage of these serotypes is found in the conjugated vaccines, which are more relevant to our communities. This paper reviews the emergence and the steady increase in the prevalence of penicillin-resistant pneumococcal strains in Saudi Arabia and Kuwait during the last 10 years. It discusses the trends, mechanisms of resistance and factors associated with the emergence, dissemination, and colonization of resistant organisms and suggests options available to clinicians for management of infections due to PRSP.

Bellary, India achieves negligible case fatality due to Japanese encephalitis despite no vaccination: an outbreak investigation in 2004

OBJECTIVE

To confirm the existence of the outbreak of suspected Japanese encephalitis, identify the source, to understand the circumstances due to which the outbreak was taking place and to suggest measures for its control.

METHODS

The team visited Bellary from 4th to 10th Sept, 2004. The team interviewed the key persons and analyzed the records at District Surveillance Unit and Entomological Surveillance Unit and case records of suspected JE cases admitted in Encephalitis ward in Vijay Nagar Institute of Medical Sciences (VIMS). Eco-entomological survey was done in houses and surroundings of 3 randomly selected cases of Encephalitis in rural and urban areas of District Bellary. Their family members and neighbors were also asked for the awareness and presence of disease. Data was analyzed for epidemiological and clinical profiles.

RESULTS

The suspected JE cases were being reported from end of June 2004. The cases were sporadic and out of 34 cases reported to VIMS (till 10th of September), 32 were from Bellary district and 2 were from adjoining Andhra Pradesh. Among these 32, 22 were from Bellary Taluk, which in turn were mainly concentrated (10 were reported) in urban Bellary. The case fatality rate was zero as no death was reported. Entomological surveillance (done by District Surveillance Unit) revealed a high outdoor presence of Culex tritaeniorhynchus as well as an indoor rising density of this mosquito from 2 per man hour catch in January to 22 in the month of August in the affected villages. On the contrary, the investigations on 7th and 8th September revealed high densities of An.subpictus and An. peditaenatus and nil of Culex species in the urban areas. Amplifier host of pigs and water birds were occasionally sighted in the area.

CONCLUSION

A good community awareness of encephalitis, a prompt referral system and a good supportive treatment for the patients and a good surveillance system and response were observed. Very close proximity with amplifying hosts of pigs was avoided by the community, though piggeries were still not very far away (1-3 Km). These may explain the reduction in cases, deaths and disabilities due to this disease in this district over the years. Possibilities of mutant strain which is less virulent and/or a better immune status of at risk population may also need to be explored. The impact of the mass vaccination with SA 14-14-2, imported from China in Bellary during July, 2006 remains to be evaluated. This will further decrease the case load.

Anti-diabetic activity of flowers of Hibiscus rosasinensis

The ethanol extract of flowers of Hibiscus rosasinensis at doses of 250 mg/kg and 500 mg/kg significantly reduced the blood glucose level in both acute (1, 3, 5 h) and sub acute (1, 3, 5, 7 days) treatments.

An evaluation of diarrheal diseases and acute respiratory infections control programmes in a Delhi slum

OBJECTIVE

Effective early management at home level and health seeking behavior in case of appearance of danger signs are key strategies in Acute respiratory Infections (ARI) and Acute Diarrheal Diseases (ADD) where majority of episodes are self-limiting and viral in origin. Integrated Management of Childhood illnesses (IMNCI) also envisages that family and community health practices especially health care seeking behaviors are to be improved to reduce childhood morbidity, mortality and cost of admissions to hospitals. Thus, a study was undertaken at an urban slum area--'Gokul Puri' in Delhi, among under-5 children with the aim to assess the magnitudes of ARI and ADD.

METHODS

A Cross-sectional survey was conducted in this urban slum of Trans-Yamuna, covering 1307 under-5 children for five days starting from 9th of August, 2004. Survey team consisted of 14 FETP Participants (WHO Fellows) from India, Nepal, Myanmar, Bhutan and Sri Lanka. A pre-tested, house-hold tally marking form was used to interview the caretakers/mothers. History of episodes of ARI and/or ADD in the last two weeks was asked. Health care practices including use of ORS &home available fluids in diarrhea, continued feeding during diarrhea, awareness of danger signs of ARI &ADD and medical advice sought were asked of those mothers whose children had such an episode.

RESULTS

191 (14.6 %) of 1307 children surveyed, had an attack of ARI in the preceding two wk. The common symptoms of ARI cases were mild running nose (78%), cough (76.4%) and/or fever (45.5%). Only 8 (4%) had fast breathing. One or more danger signs were known to 80% (152/191) of mothers and an equal number (80%) of mothers had sought treatment. ARIs are mostly mild or self limiting but only 16% of caretakers perceived so and doctors also prescribed medicines. The attack rate of Acute Diarrheal Diseases was 7.73% in the study and ADD's annual adjusted morbidity rate was 1.69 episodes per child per year. Though nearly three-fourth of mothers (71.3%) had reported to be seeking medical advice (which is not needed in mild episodes of diarrhea) the ORS use was 38.6%, use of Home available fluids (HAF) was 42% and continued feeding was 50% during the ADD episode and awareness of at least two danger signs was present in 34%.

CONCLUSION

Though aware of danger signs of ARI, care takers were still seeking medical advice for mild cases of ARI and doctors were prescribing drugs. Correct home based management e.g. use of ORS, continued feeding etc. was deficient in the community. Knowledge of danger symptoms was low and medical advice was being sought and drugs were being prescribed for ADD, too.

Chikungunya viral disease in district Bhilwara (Rajasthan) India

An investigation of chikungunya outbreak cases was carried out in Bhilwara District, Rajasthan during Aug-Sep 2006. Fever with multiple joint pains was the first presenting feature. Aedes larval surveys indicate high Breteau index (78.6 to 200), House index (48.0 to 83.3) & Container index (41.1 to 73.6) above the critical index. Out of 40 sera samples tested, 12 showed HI antibodies for chikungunya virus in high titres and another five were positive for IgM antibodies against chikungunya. The clinico-epidemiological, laboratory and entomological investigations confirm that this episode of fever was due to chikungunya fever. Strengthening and intensification of surveillance along with educating the community were recommended for control of outbreak.

Mother and child service coverage: reproductive and child health programme in Alwar district, Rajasthan state

Present study was conducted to assess the child immunization coverage and availability of safe motherhood intervention services for expecting mothers under RCH programme in Alwar district. WHO-30 cluster sampling method was used and 26 rural and 4 urban clusters were surveyed. Fully immunized children were more in urban areas (82.1%) as compared to rural (45.1%) areas. The immunization coverage was more or less similar in both sexes. BCG and Measles coverage was also higher i.e. 89.3% and 85.7% in urban areas than 69.61%, and 52.2% in rural respectively. High drop out rate was found for DPT (25.3%) and OPV (23.2%) in rural areas as compare to urban (7.70/ each). Failure of immunization in rural areas was mainly due to unawareness of need for immunization (35.4%), mother too busy in 16.8%, place and time not known in 9.7%, place for immunization too far 8.8% and 7.1% each for unaware of need to return for subsequent doses, fear of side reactions and vaccinator absent. TT immunization coverage was mainly through Government source and two third of the mothers were immunized in both urban and rural areas. 71.4% of urban and 36.1% of the rural mothers received ANC >=3. However the iron folic acid supplementation was similar in urban and rural areas. Place of delivery was mainly hospital in urban areas (71.4%) and were home (61.7%) in rural areas. Hospital staff (Govt. or pvt.) conducted 82.1% of the deliveries in urban areas as compared to 58.5% in rural. The ANM/ Health staff (56.4%) and family members (27.0%) were main source of information for mother for the need of mother and child immunization.

An entomological study on the dengue vectors during outbreak of dengue in Tiruppur town and its surroundings, Tamil Nadu, India

Tiruppur town and its surroundings of Tamil Nadu state had reported the rise in dengue cases and some deaths during July, 2005. A team from NICD branch, Coonoor investigated the outbreak of dengue during August, 2005. Due to acute scarcity of water, people in Tiruppur town and surrounding rural areas store water in cement tanks and other containers which facilitated the prolific breeding of the dengue vector mosquitoes. The Aedes aegypti adult and larval survey conducted in randomly selected areas and the larval breeding indices and adult mosquito density were found to be above the critical levels. The state health and municipal authorities had initiated the control measures in urban areas. However in rural areas, these measures needed to be sustained and surveillance for dengue cases to be strengthened for timely control and prevention of the future outbreaks of this disease.

Child survival and safe motherhood program in Rajasthan

OBJECTIVE

This study was planned to evaluate the MCH services, particularly immunization in rural areas of the poor-performing state of Rajasthan.

METHODS

A community-based, cross-sectional survey using the WHO 30 cluster technique was carried out as a field exercise by participants of 9th Field Epidemiology Training Programme (FETP) course by National Institute of Communicable Diseases (NICD) in rural areas of Alwar district of Rajasthan.

RESULTS

Less than one third (28.9%) of children, aged 12-23 months, were fully immunized with BCG, 3 DPT, 3 OPV and Measles vaccines; around a quarter (26.5%) had not received even a single vaccine (non immunized), and little less than half (44.5%) were found partially immunized. Around half of the eligible children were vaccinated for BCG (55.9%) and Measles (43.6%). Though nearly two-third (66.8%) were covered with first dose of DPT and OPV, but about one third of these children dropped out of third dose of DPT and OPV for various reasons. National Family Health Survey (NFHS) data also had revealed that BCG coverage was 64.3%; measles was 36.2%; and coverage by DPT 1, 2, 3 and Polio 1,2 and 3 were 64.4%, 57.0%, 46.6% and 77.5%, 71.1% and 54.4% respectively in rural areas. The main reasons for drop-out or non-immunization was "lack of information about the immunization programme" (41.3%). Though nearly all (more than 96%) of the children were immunized through Government established centers, but immunization cards/documents were made available only to 27.6% of children.

CONCLUSION

The problem of low coverage and high drop-out rate of immunization could be overcome by creating awareness of the program and relevance of 2nd and 3rd doses of DPT and polio vaccines. Increasing community participation through intensive and extensive health education campaign should also be undertaken. Since most of the deliveries were done at home under the supervision of untrained midwives, training programme as well as involving them in IEC activities should be contemplated.

Progression of Type I to Type II paralysis in acute organophosphorous poisoning: Is oxidative stress significant?

Organophosphorous poisoning is a common method of deliberate self-harm in countries where the pesticides are readily available and can result in type I, II and/or III paralysis. The in-hospital morbidity and mortality of the poisoning are mostly associated with type II paralysis (intermediate syndrome). The aim of this study was to determine the role of oxidative stress in relation to the severity of poisoning and development of type II paralysis in patients suffering from acute organophosphate poisoning. This prospective study was carried out at the Christian Medical College Hospital. Thirty-two patients with acute organophosphorous poisoning, admitted in one medical unit over 17 months, were included in the study. They were clinically assessed for severity of poisoning and paralysis during the first 10 days of their hospitalisation. Temporal profiles of butyrylcholinesterase (BuChE) and oxidative stress parameters, for 4, 7 and 10 days of hospitalisation, were established in 25 of these patients. Type I and II paralysis were associated with severe poisoning. The majority of patients with type II paralysis had prior evidence of type I paralysis. The pattern of muscles that were paralysed in type I paralysis occurring alone and in type I paralysis proceeding to type II paralysis were similar. BuChE was significantly inhibited in all patients. Oxidative stress occurred in acute organophosphate poisoned patients and was greater in severe poisoning. The results suggest that type I paralysis may progress to type II paralysis in severely poisoned patients. They demonstrate early occurrence of oxidative stress in severe acute organophosphate poisoning. However, the development of type II paralysis is not associated with the level of oxidative stress. They suggest that mechanisms other than acetylcholine induced oxidative stress may be involved in the progression of type I to type II paralysis.

Two-generation marker-aided backcrossing for rapid conversion of normal maize lines to quality protein maize (QPM)

The low nutritive value of maize endosperm protein is genetically corrected in quality protein maize (QPM), which contains the opaque 2 gene along with numerous modifiers for kernel hardness. We report here a two generation marker-based backcross breeding program for incorporation of the opaque 2 gene along with phenotypic selection for kernel modification in the background of an early maturing normal maize inbred line, V25. Using the flanking marker distances from opaque 2 gene in the cross V 25 xCML 176, optimum population size for the BC(2) generation was computed in such a way that at least one double recombinant could be obtained. Whole genome background selection in the BC(2) generation identified three plants with 93 to 96% recurrent parent genome content. The three BC(2)F(2) families derived from marker identified BC(2) individuals were subjected to foreground selection and phenotypic selection for kernel modification. The tryptophan concentration in endosperm protein was significantly enhanced in all the three classes of kernel modification viz., less than 25%, 25--50% and more than 50% opaqueness. BC(2)F(3) lines developed from the hard endosperm kernels were evaluated for desirable agronomic and biochemical traits in replicated trials and the best line was chosen to represent the QPM version of V25, with tryptophan concentration of 0.85% in protein. The integrated breeding strategy reported here can be applied to reduce genetic drag as well as the time involved in a conventional line conversion program, and would prove valuable in rapid development of specialty corn germ plasm.

Studies on heme release from normal and metal ion reconstituted hemoglobin mediated through ionic surfactant

The interaction of metal-substituted hemoglobin (MHb), where M = Ni and Cu (T-state with no O2 and CO binding capability) and Fe (R-state when CO is bound), with cationic cityl trimethyl ammonium bromide (CTAB) and anionic (sodium dodecyl sulfate-SDS) surfactants has been studied using spectroscopic techniques-UV-visible, electron paramagnetic resonance (EPR), and Fourier transform-Raman-with additional supportive evidence coming from conductivity measurements. We observed the loss of 5-coordination in all three hemoglobins below the critical micelle concentration (CMC) of surfactant, with noticeable differences, suggesting differing mechanisms involved in this process. In addition, above the CMC, Ni- and Cu-hemes were found to leave their proteins more easily than Fe-heme, presumably due to weaker or no bond with the proximal histidine in the former. The released heme is stabilized by micellar media through a hydrophobic interaction process. Of the two surfactants, CTAB seems to be capable of releasing the heme better than SDS and it is attributed to the greater hydrophobicity of CTAB though the charge of the surfactant plays an important role.

SARS: the new challenge to international health and travel medicine

Severe acute respiratory syndrome [SARS], the first severe new infectious disease of this millennium, caused widespread public disruption. By July 2003, 8427 probable SARS cases had been reported from 29 countries with a case fatality rate of 9.6%. The new febrile respiratory illness spread around the world along the routes of international air travel, with outbreaks concentrated in transportation hubs or densely populated areas. The etiologic agent was identified as a novel coronavirus, SARS-CoV. The disease is transmissible person-to-person through direct contact, large droplet contact and indirect contact from fomites and unwashed h and s. Saudi Arabia successfully prevented the entry of the disease by imposing travel restrictions, special entry requirements, screening procedures at airports, including temperature checks, and quarantine. Ongoing efforts are aimed at developing case investigation, case management and surveillance protocols for SARS

SARS: the new challenge to international health and travel medicine

Severe acute respiratory syndrome (SARS), the first severe new infectious disease of this millennium, caused widespread public disruption. By July 2003, 8427 probable SARS cases had been reported from 29 countries with a case fatality rate of 9.6%. The new febrile respiratory illness spread around the world along the routes of international air travel, with outbreaks concentrated in transportation hubs or densely populated areas. The etiologic agent was identified as a novel coronavirus, SARS-CoV. The disease is transmissible person-to-person through direct contact, large droplet contact and indirect contact from fomites and unwashed hands. Saudi Arabia successfully prevented the entry of the disease by imposing travel restrictions, special entry requirements, screening procedures at airports, including temperature checks, and quarantine. Ongoing efforts are aimed at developing case investigation, case management and surveillance protocols for SARS.

Historical alpha-HCH budget in the Arctic Ocean: the Arctic Mass Balance Box Model (AMBBM)

An Arctic Mass Balance Box Model (AMBBM) has been developed to calculate a sequential historical alpha-hexachlorocyclohexane (alpha-HCH) budget in the Arctic Ocean from its introduction in the 1940s up to the present. The AMBBM is created in the context of the Arctic as a receptor, and has three major components: the air concentration module, the loading from Arctic river module and the transport/transformation module. The results of the model provide a more complete depiction of the behavior of alpha-HCH within the Arctic Ocean. Model output includes annual concentrations in Arctic air and water, annual alpha-HCH loading to, removal from the Arctic Ocean and annual cumulative burden of alpha-HCH in the Arctic waters from 1945 to 2000. Our model results compare well with published data in the 1980s and 1990s and show that the alpha-HCH burden in the Arctic Ocean started to accumulate in the early 1940s and reached the highest value of 6670 t in 1982, 1 year before China banned the use of technical HCH. Since then the burden of alpha-HCH in Arctic waters has decreased quickly by an average annual rate of approximately 270 ty(-1) during the 1990s, decreasing from 4220 t in 1990 to 1550 t in 2000. The complete elimination of alpha-HCH from Arctic waters would require another two decades. The total loading between 1945 and 2000 was 27700 t accounting for approximately 0.6% of total global alpha-HCH emission from agricultural land to the atmosphere. Differences in loadings of alpha-HCH to the North American Arctic Ocean and Eurasian Arctic Ocean are also discussed.

The characteristics of very short stay ICU admissions and implications for optimizing ICU resource utilization: the Saudi experience

OBJECTIVE

Patients with very short stays (<24 hours) in intensive care units (ICUs) constitute a distinct group with a high turnover rate and a unique patient mix. Our aim was to study their characteristics with the aim of developing strategic approaches for better and more appropriate utilization of ICU resources.

DESIGN

Prospective cohort study.

SETTING

Adult medical/surgical ICU in a tertiary care teaching hospital.

STUDY PARTICIPANTS

All admissions in an adult ICU from March 1999 to February 2001 and staying <24 hours were enrolled. Relevant data were collected on these patients, their course and outcome, and analyzed after categorizing patients according to: (i) the nature of admission; and (ii) risk of death (ROD) estimated by Mortality Probability Model II(0).

RESULTS

Patients staying <24 hours (n = 304) formed 27.8% of all ICU admissions, with an ICU mortality rate of 26.3%. Only 45.4% of them utilized ICU-specific procedures. Around one-third (32.6%) were elective admissions comprising younger patients, with a significantly lower prevalence of chronic illness, a lower ROD, and utilization of less ICU-specific procedures, with very few mortalities. When stratified using RODs into low-, intermediate-, and high-risk groups, significant differences were found with respect to age, nature of ICU admission, presence of chronic illness, utilization of ICU-specific procedures, having do-not-resuscitate (DNR) orders, length of ICU stay, and ICU and hospital outcomes.

CONCLUSIONS

Our study has provided crucial input for the study of strategic change towards more optimal utilization of scarce ICU resources. Implementing protocols to target ICU care to patients most likely to benefit, making DNR decisions early in the hospital stay, and operating an Intermediate Care Unit have been proposed as strategic approaches.

Evidence of the impact of ENSO events on temporal trends of hexachlorobenzene air concentrations over the Great Lakes

This study presents an evidence for association of the air concentrations of HCB measured in the Great Lakes region with the El Niño-Southern Oscillation (ENSO) during the 1990s. The measured HCB concentrations in the atmosphere collected by the Integrated Atmospheric Deposition Network (IADN) program in the Great Lakes during the 1990s show strong correlations with the Multivariate ENSO index (MEI) during winter (December-February) and spring (March-May) seasons. These correlations are stronger in the western upper Great Lakes than in the eastern portion of the Great Lakes ecosystem (lake Ontario), and correspond well to the spatial variability of the surface air temperature in North America during El Niño years. Departures of HCB air concentrations for each winter during 1992-1999 from that averaged over all winters of 1992-1999, i.e. the anomaly, also show the same temporal trend as that of the MEI during the same period. In the same time period, it has been reported that direct HCB emissions from application of HCB in agriculture, from industrial sources in North America and in the rest of the world have decreased substantially compared to those in the 1970s and could not by themselves account for observed HCB air concentrations around the Great Lakes since the 1990s. Interannual fluctuations of HCB concentrations are caused most likely by reemission due to volatilization of HCB from the soil contaminated from past use, followed by long-range transport associated with ENSO events. In addition to the high correlation (R(2)=0.61) between winter HCB air concentrations averaged over the Great Lakes region and the MEI the atmospheric circulation patterns associated with ENSO events are conducive to the long-range transport of HCB into the Great Lakes region.

Antihyperglycemic activity of Caralluma attenuata

Extracts of Caralluma attenuata are screened for their antihyperglycemic activity. Ethanol, chloroform and butanol extracts were tested on glucose loaded and alloxan-induced diabetic rats. In both tests, the butanol extract, at the oral dose of 250 mg/kg, has shown statistically significant and considerable antihyperglycemic activity.

Impact of travel on international spread of antimicrobial resistance

Antimicrobial resistance, an escalating problem worldwide, affects a broad range of human diseases. Excessive and inappropriate drug usage is the key driver for the emergence of resistant organisms. Travel, trade and mass migration form an important mode for their spread. The use of molecular biology provides the means of understanding the genesis and spread of the genes for drug resistance. Antimicrobial use in veterinary practice as food additives causes selection of resistant zoonotic pathogens that may spread to humans. Comprehensive surveillance systems should be designed and implemented at local and national levels and a national resistance surveillance database operationalized. There is also need for better regulation of the use of antibiotics and education of the medical fraternity, veterinarians and the public in the appropriate use of antimicrobials.

Travel epidemiology: the Saudi perspective

The Kingdom of Saudi Arabia occupies four-fifths of the Arabian Peninsula, with a land area of 2 million square kilometres. Saudi Arabia holds a unique position in the Islamic world, as the custodian of the two holiest places of Islam, in Mecca and Medina. Annually, some 2 million Muslims from over 140 countries embark on Hajj. This extraordinary en masse migration is a unique forum for the study of travel epidemiology since the Hajj carries various health risks, both communicable and non-communicable, often on a colossal scale. Non-communicable hazards of the Hajj include stampede and motor vehicle trauma, fire-related burn injuries and accidental hand injury during animal slaughter. Communicable hazards in the form of outbreaks of multiple infectious diseases have been reported repeatedly, during and following the Hajj. Meningococcal meningitis, gastroenteritis, hepatitis A, B and C, and various zoonotic diseases comprise some of the possible infectious hazards at the Hajj. Many of these infectious and non-infectious hazards can be avoided or averted by adopting appropriate prophylactic measures. Physicians and health personnel must be aware of these risks to appropriately educate, immunize and prepare these travellers facing the unique epidemiological challenges of Hajj in an effort to minimize untoward effects. Travel epidemiology related to the Hajj is a new and exciting area, which offers valuable insights to the travel specialist. The sheer scale of numbers affords a rare view of migration medicine in action. As data is continually gathered and both national and international policy making is tailored to vital insights gained through travel epidemiology, the Hajj will be continually safeguarded. Practitioners will gain from findings of travel related epidemiological changes in evolution at the Hajj: the impact of vaccinating policies, infection control policies and public health are afforded a real-world laboratory setting at each annual Hajj, allowing us to learn from this unique phenomenon of migration medicine.

Bioterrorism--a new challenge for public health

The opening years of the new millennium have presented a new and worrisome possibility to the public, including travellers: the threat of deadly infectious diseases from biological agents being deliberately released. The possibility of bioterrorism had always seemed remote but the recent anthrax attacks by mail have made this threat of immediate relevance. The deliberate use of Bacillus anthracis with the intent to harm civilian populations has raised public health concerns about potential exposure to intentionally released Variola virus and other biological agents. There is an urgent need for countries to examine their preparedness to respond to biological weapons attacks. Given the emotional shock of even an alleged threat of a biological release, it will be wise for governments to consider how to address such dangers as an integral part of the national response to other threats to public health and well being. Physicians and other health professionals, including those providing guidance to international and domestic travellers, need to have a clear understanding of the possible agents and the appropriate therapy or prophylaxis. This paper attempts to give a perspective on the threat of bioterrorism, the consequences of its use, the likely biological agents that may be used, and the clinical presentation and management of diseases caused by some agents most likely to be used.

Policy Recognition in the Abstract Hidden Markov Model

In this paper, we present a method for recognising an agent's behaviour in dynamic, noisy, uncertain domains, and across multiple levels of abstraction. We term this problem on-line plan recognition under uncertainty and view it generally as probabilistic inference on the stochastic process representing the execution of the agent's plan. Our contributions in this paper are twofold. In terms of probabilistic inference, we introduce the Abstract Hidden Markov Model (AHMM), a novel type of stochastic processes, provide its dynamic Bayesian network (DBN) structure and analyse the properties of this network. We then describe an application of the Rao-Blackwellised Particle Filter to the AHMM which allows us to construct an efficient, hybrid inference method for this model. In terms of plan recognition, we propose a novel plan recognition framework based on the AHMM as the plan execution model. The Rao-Blackwellised hybrid inference for AHMM can take advantage of the independence properties inherent in a model of plan execution, leading to an algorithm for online probabilistic plan recognition that scales well with the number of levels in the plan hierarchy. This illustrates that while stochastic models for plan execution can be complex, they exhibit special structures which, if exploited, can lead to efficient plan recognition algorithms. We demonstrate the usefulness of the AHMM framework via a behaviour recognition system in a complex spatial environment using distributed video surveillance data.

A prospective study of prolonged stay in the intensive care unit: predictors and impact on resource utilization

OBJECTIVE

To evaluate the predictors of prolonged Intensive Care Unit (ICU) stay and the impact on resource utilization.

DESIGN

Prospective study.

SETTING

Adult medical/surgical ICU in a tertiary-care teaching hospital.

STUDY PARTICIPANTS

All admissions to the ICU (numbering 947) over a 20-month period were enrolled. Data on demographic and clinical profile, length of stay, and outcome were collected prospectively. The ICU length of stay and mechanical ventilation days were used as surrogate parameters for resource utilization. Potential predictors were analyzed for possible association with prolonged ICU stay (length of stay > 14 days).

RESULTS

Patients with prolonged ICU stay formed only 11% of patients, but utilized 45.1% of ICU days and 55.5% of mechanical ventilation days. Non-elective admissions, readmissions, respiratory or trauma-related reasons for admission, and first 24-hour evidence of infection, oliguria, coagulopathy, and the need for mechanical ventilation or vasopressor therapy had significant association with prolonged ICU stay. Mean APACHE II and SAPS II were slightly higher in patients with prolonged stay. ICU outcome was comparable to patients with < or = 14 days ICU stay.

CONCLUSIONS

Patients with prolonged ICU stay form a small proportion of ICU patients, yet they consume a significant share of the ICU resources. The outcome of this group of patients is comparable to that of shorter stay patients. The predictors identified in the study can be used in targeting this group to improve resource utilization and efficiency of ICU care.