Issues relevant to the adoption and modification of hospital infection-control recommendations for avian influenza (H5N1 infection) in developing countries

Risks to healthcare workers with emerging diseases: lessons from MERS-CoV, Ebola, SARS, and avian flu

PURPOSE OF REVIEW

Several viral diseases have emerged and impacted healthcare systems worldwide. Healthcare personnels (HCPs) are at high risk of acquiring some emerging infections while caring for patients. We provide a review of risk factors, evidence of infection in HCPs, and prevention strategies with Middle East respiratory syndrome coronavirus, Ebola virus disease (Ebola), severe acute respiratory syndrome (SARS), and avian influenza.

RECENT FINDINGS

HCP-related infections with Middle East respiratory syndrome coronavirus, Ebola, and SARS have been reported among 1-27%, 2.5-12%, and 11-57% of total cases, respectively. The case fatality rate of Ebola in HCPs has been reported up to 73%. The WHO guidelines for the global surveillance of SARS were developed in 2004 and used as a template for other emerging diseases preparedness. Risks to HCPs with emerging diseases are related to inappropriate and insufficient infection control measures during an initial encounter, at the beginning of outbreak and with an overwhelming number of patient cases. To date, there are no reports of avian influenza transmission to HCPs from affected cases.

SUMMARY

Early and rapid detection of suspected infected patients with communicable diseases along with appropriate infection control practice, education, national and global preparedness guidelines would help to prevent disease transmission to HCPs.

Fast-track ventilation strategy to cater for pandemic patient isolation surges

BACKGROUND

The shortage of isolation facilities in hospitals was highlighted during the severe acute respiratory syndrome (SARS) pandemic in 2003. Yet, as the nature and scale of future pandemics cannot be adequately estimated, it is difficult to justify construction of sufficient isolation facilities. A fast-track and cost-effective ventilation strategy for the retrofitting of existing general wards could help hospitals deal with patient surges.

AIM

This article reviews the effectiveness of a fast-track, makeshift isolation approach employed during the SARS outbreak which involved installing simple window-mounted exhaust fans to create negative-pressure airflow in hospital general wards.

METHODS

Computational fluid dynamics (CFD) was used to assess by simulation whether the approach adopted meets US Centers for Disease and Control and Prevention requirements for properly constructed isolation wards.

FINDINGS

CFD simulation revealed that this makeshift approach could match the ventilation standards of isolation rooms. The approach was certainly effective as no secondary infections were reported in hospitals that used it during SARS.

CONCLUSIONS

When there is a shortfall in isolation facilities to accommodate a surge in patients, the proposed ventilation set-up could be quickly and widely implemented by existing general wards.

Reduction of seasonal influenza transmission among healthcare workers in an intensive care unit: a 4-year intervention study in Thailand

OBJECTIVE

To evaluate the feasibility and effectiveness of an influenza control bundle to minimize healthcare-associated seasonal influenza transmission among healthcare workers (HCWs) in an intensive care unit (ICU) equipped with central air conditioning.

METHODS

A quasi-experimental study was conducted in a 500-bed tertiary care center in Thailand from July 1, 2005, through June 30,2009. The medical ICU (MICU) implemented an influenza control bundle including healthcare worker (HCW) education, influenza screening of adult community-acquired pneumonia patients, antiviral treatment of patients and ill HCWs who tested positive for influenza, promotion of influenza vaccination among HCWs, and reinforcement of standard infection control policies. The surgical ICU (SICU) and coronary care unit (CCU) received no intervention.

RESULTS

The numbers of influenza infections among HCWs during the pre- and postintervention periods were 18 cases in 5,294 HCW days and 0 cases in 5,336 HCW-days in the MICU (3.4 vs 0 cases per 1,000 HCW-days; P ! .001), 19 cases in 4,318 HCW-days and 20 cases in 4,348 HCW-days in the SICU (4.4 vs 4.6 cases per 1,000 HCW-days; Pp.80), and 18 cases in 5,000 HCW-days and 18 cases in 5,143 HCW-days in the CCU (3.6 vs 3.5 cases per 1,000 HCW-days; Pp.92), respectively. Outbreak-related influenza occurred in 7 MICUHCWs, 6 SICU HCWs, and 4 CCU HCWs before intervention and 0 MICU HCWs, 9 SICU HCWs, and 8 CCU HCWs after intervention.Before and after intervention, 25 (71%) and 35 (100%) of 35 MICU HCWs were vaccinated, respectively (P ! .001); HCW vaccination coverage did not change significantly in the SICU (21 [70%] of 30 vs 24 [80%] of 30; Pp.89) and CCU (19 [68%] of 28 vs 21 [75%]of 28; Pp.83). The estimated costs of US $6,471 per unit for postintervention outbreak investigations exceeded the intervention costs of US $4,969.

CONCLUSION

A sustained influenza intervention bundle was associated with clinical and economic benefits to a Thai hospital.

Complementary monoclonal antibody-based dot ELISA for universal detection of H5 avian influenza virus

BACKGROUND

Rapid diagnosis and surveillance for H5 subtype viruses are critical for the control of H5N1 infection.

RESULTS

In this study, H5 Dot ELISA, a rapid test for the detection of avian H5N1 influenza virus, was developed with two complementary H5 monoclonal antibodies. HA sequencing of escape mutants followed by epitope mapping revealed that the two Mabs target the epitope component (189th amino acid) on the HA protein but are specific for different amino acids (189Lys or 189Arg). Gene alignment indicated that these two amino acids are the most frequent types on this position among all of the H5 AIV reported in GeneBank. These two H5 Mabs were used together in a dot ELISA to detect H5 viral antigen. The detection limit of the developed test for multiple clades of H5N1 viruses, including clades 0, 1, 2.1, 2.2, 2.3, 4, 7, and 8, was less than 0.5 hemagglutinin units. The specificity of the optimized dot ELISA was examined by using 100 H5 strains, including H5N1 HPAI strains from multiple clades, 36 non-H5N1 viruses, and 4 influenza B viruses. No cross-reactivity was observed for any of the non-H5N1 viruses tested. Among 200 random poultry samples, the test gave 100% positive results for all of the twelve RT-PCR-positive samples.

CONCLUSIONS

Considering that the test is convenient for field use, this H5 Dot ELISA can be used for on-site detection of H5N1 infection in clinical or environmental specimens and facilitate the investigation of H5N1 influenza outbreaks and surveillance in poultry.

Outbreak of influenza A (2009) H1N1 among Thai healthcare workers: is it time to integrate a vaccination program?

We report an outbreak of influenza A (2009) H1N1 among healthcare workers in a coronary care unit in Thailand. The attack rate was 32% (7 of 32 healthcare workers) after detection of influenza A (2009) H1N1 pneumonia in the index patient. Estimated costs for the outbreak investigation and control plan were 12-fold higher than estimated costs of vaccination for healthcare workers.

Mitigation approaches to combat the flu pandemic

Management of flu pandemic is a perpetual challenge for the medical fraternity since time immemorial. Animal to human transmission has been observed thrice in the last century within an average range of 11-39 years of antigenic recycling. The recent outbreak of influenza A (H1N1, also termed as swine flu), first reported in Mexico on April 26, 2009, occurred in the forty first year since last reported flu pandemic (July 1968). Within less than 50 days, it has assumed pandemic proportions (phase VI) affecting over 76 countries with 163 deaths/35,928 cases (as on 15(th) June 2009). It indicated the re-emergence of genetically reassorted virus having strains endemic to humans, swine and avian (H5N1). The World Health Organisation (WHO) member states have already pulled up their socks and geared up to combat such criticalities. Earlier outbreaks of avian flu (H5N1) in different countries led WHO to develop pandemic preparedness strategies with national/regional plans on pandemic preparedness. Numerous factors related to climatic conditions, socio-economic strata, governance and sharing of information/logistics at all levels have been considered critical indicators in monitoring the dynamics of escalation towards a pandemic situation.The National Disaster Management Authority (NDMA), Government of India, with the active cooperation of UN agencies and other stakeholders/experts has formulated a concept paper on role of nonhealth service providers during pandemics in April 2008 and released national guidelines - management of biological disasters in July 2008. These guidelines enumerate that the success of medical management endeavors like pharmaceutical (anti-viral Oseltamivir and Zanamivir therapies), nonpharmaceutical interventions and vaccination development etc., largely depends on level of resistance offered by mutagenic viral strain and rationale use of pharmaco therapeutic interventions. This article describes the mitigation approach to combat flu pandemic with its effective implementation at national, state and local levels.

Antiviral therapy for avian influenza virus (H5N1) infection at 2 Thai medical centers: survey findings and implications for pandemic preparedness

In a survey of 150 physicians from an area where avian influenza virus (H5N1) infection is endemic, practice location (adjusted odds ratio [aOR], 4.45 [95% confidence interval {CI}, 1.02-26.4]) and the belief that rapid tests reliably predicted H5N1 infection (aOR, 5.6 [95% CI, 1.14-33.6]) were associated with not prescribing antiviral therapy; the belief that antiviral therapy reduced mortality was associated with prescribing an antiviral agent (aOR, 0.56 [95% CI, 0.14-0.95]).

A nationally coordinated laboratory system for human avian influenza A (H5N1) in Thailand: program design, analysis, and evaluation

BACKGROUND

The first phase of national surveillance for avian influenza (H5N1) human disease in Thailand occurred over a 4-month period that began on 1 December 2003. Subsequently, a nationally coordinated laboratory system (NCLS) for avian influenza (H5N1) was created to assess population-based surveillance, specimen procurement, case detection, and reporting at the national level.

METHODS

We conducted a pre- and postintervention study to evaluate the NCLS designed during the 6-week interval from 1 April through 15 May 2004. During the pre-NCLS period (1 December 2003 through 31 March 2004), 12 cases of human avian influenza (H5N1) were confirmed. During the post-NCLS period (16 May 2004 through 31 December 2006), interventions were implemented for human avian influenza (H5N1) surveillance, case detection, and expedited, computer-based reporting.

RESULTS

During the pre- and post-NCLS periods, 777 (85%) of 915 and 10,434 (95%) of 11,042 clinical respiratory specimens, respectively, were adequate for confirmatory testing (P<.001), the median time from procurement to results decreased from 17 days (range, 14-24 days) to 1.8 days (range, 0.25-4 days; P<.001), and the duration of specimen shipment decreased from 46.5 h to 21.1 h (P<.001). Thirteen cases of avian influenza (H5N1) were detected during the 31-month postintervention period. H5N1 reverse-transcriptase polymerase chain reaction and real-time reverse-transcriptase polymerase chain reaction sensitivity was 100% and specificity was 99.8%.

CONCLUSIONS

The NCLS exemplifies a systematic approach to national surveillance for avian influenza A (H5N1). This NCLS program in Thailand serves as a model for human avian influenza (H5N1) preparedness that can be adopted or modified for use in other countries.

Influenza A/H5N1 infection: other treatment options and issues

Antiviral therapy and vaccination are important strategies for the control of human influenza/H5N1 disease, but the efficacy of these modalities is limited by timing of administration and shortage of supply. Lung protective ventilation strategy with a low tidal volume and low pressure, in addition to a conservative fluid management approach, is recommended when treating patients with ARDS. Low-dose steroids may be considered in the treatment of refractory septic shock. Non-invasive positive pressure ventilation (NPPV) may play a limited supportive role for early ARDS/acute lung injury, but it is contra-indicated in critically ill patients with multi-organ failure and haemodynamic instability. NPPV and oxygen therapy should be applied in healthcare facilities with good ventilation and respiratory protection as substantial exposure to exhaled air occurs within a 0.5 m and 0.4 m radius of patients receiving NPPV and oxygen via a simple mask, respectively. Intravenous gammaglobulin should be used with caution for treatment of reactive haemo-phagocytosis due to its thrombogenic effects, whereas the role of etoposide needs evaluation with animal models. Passive immunotherapy in the form of convalescent plasma may be useful as rescue therapy. More data are needed to explore the potential role of other drugs with immuno-modulating properties such as statins. Healthcare workers currently must apply strict standards, contact and droplet precautions when dealing with suspected cases, and upgrade to airborne precautions when performing aerosol-generating procedures. Non-pharmacological measures such as early case isolation, household quarantine, school/workplace closure, good community hygiene and restrictions on travel are useful measures in controlling a pandemic.