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disease (PPHSN 2004). Similar coercive measures might be needed if vaccination became necessary to contain the pandemic.

Funding

Resource-limited countries need to formulate a feasible national influenza pandemic preparedness plan based on existing resources and the size and structure of the population. High political support is paramount for allocation of funding designated for emergency situations such as an influenza pandemic. The planning process should include identification of possible resources to fund pandemic response.

Global Strategy for the Progressive Control of Highly Pathogenic Avian Influenza

The likely progressive spread of highly pathogenic avian influenza (HPAI) into new regions will require pro-active intervention by the countries at risk, especially those situated along wild bird migration routes. Increased surveillance, detection capabilities and emergency preparedness will be required. Public awareness, along with education and training of veterinary professionals and para-professionals, farmers, marketers, poultry transport contractors and egg collectors, will be required to ensure that the disease is either prevented or detected and controlled, in order to prevent its establishment and maintenance in newly colonised ecosystems (FAO 2005).

The FAO and OIE, in collaboration with the WHO, have taken the initiative to start the process of developing the Global Strategy of Progressive Control and Eradication of HPAI. The overall goal of the strategy is to eventually eliminate HPAI from the domestic poultry sector in Asia and Europe, and prevent further introduction of HPAI into noninfected countries, thereby minimising the global threat of a human pandemic, promoting viable poultry production, enhancing robust regional and international trade in poultry and poultry products, increasing safety of food and feeds, and improving the livelihoods of all poultry sector stakeholders, especially the rural poor (FAO, OIE, WHO 2005).

Multiple opportunities exist for controlling highly pathogenic avian influenza: 1) prevent contact between wild and domestic poultry by use of screened poultry houses and treated water; 2) prevent contact between domestic waterfowl and gallinaceous poultry by use of screened houses and treated water and by exclusion of waterfowl from “wet markets”; 3) eradicate H5/H7 influenza viruses from gallinaceous poultry by culling or by using vaccines to prevent disease and transmission; 4) prevent or minimise contact between poultry, pigs, and humans and make vaccines and antiviral drugs available (Webster 2006).

Pandemic Period

During a pandemic phase the primary objective should be containment. It has been said that success depends on early identification of the first cluster of cases caused by the pandemic strain (Ferguson 2004), and on detection of a high proportion of ongoing cases (Ferguson 2005). Therefore, optimal surveillance at this point is essential for successful containment.

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Surveillance

Pandemic surveillance should include monitoring of the following events: hospital admissions of suspected or confirmed cases of pandemic strain influenza, deaths among suspected or confirmed cases of influenza due to the pandemic strain, workforce absenteeism in services designated as essential, vaccine usage for routine and pandemic strain influenza vaccines (if these are available), adverse vaccine events attributed to the pandemic strain vaccine (if available), data collection for later use in the calculation of effectiveness of the pandemic strain vaccine, monitoring pneumococcal vaccine use and adverse events associated with its use (if this vaccine is available and being used), and monitoring of antiviral use and adverse events that may be attributed to antiviral use, if applicable. Moreover, a mechanism for data aggregation, interpretation and transmission for decision making must be ensured. The daily reporting of cases to national authorities and to the WHO, including information on the possible source of infection, must be performed (WHO 2005e).

Treatment and Hospitalisation

While the numbers of affected persons are still small, patients with suspected or proven influenza A (H5N1) should be hospitalised in isolation for clinical monitoring, appropriate diagnostic testing, and antiviral therapy. Both the patients and their families require education in personal hygiene and infection-control measures. The management is based on supportive care with provision of supplementary oxygen and ventilatory support. Patients with suspected influenza A (H5N1) should promptly receive a neuraminidase inhibitor pending the results of diagnostic laboratory testing (WCWHO 2005). For more details, see Hoffmann 2006.

Human Resources: Healthcare Personnel

High-efficiency masks (NIOSH-certified N-95 or equivalent), long-sleeved cuffed gowns, face shield or eye goggles, and gloves are recommended for healthcare workers in contact with patients . When feasible, the number of healthcare workers with direct patient contact and the access to the environment of patients should be limited. Healthcare workers involved in high-risk procedures (e.g., aerosolgenerating procedures) should be considered for pre-exposure prophylaxis (WCWHO 2005).

Geographically Targeted Prophylaxis and Social Distancing Measures

Models can be used to estimate influenza-associated morbidity and mortality. Even though current models used for developed countries are not useful for developing countries, some interesting principles may be considered for the latter.

By means of a simulation model of influenza transmission in Southeast Asia, it was recently suggested that the elimination of a nascent pandemic may be feasible using a combination of geographically targeted prophylaxis and social distancing measures, if the basic reproduction number of the new virus is below 1.8 (Ferguson 2005). The basic reproduction number R0 (Anderson 1992) quantifies the transmis-

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sibility of any pathogen, and is defined as the average number of secondary cases generated by a typical primary case in an entirely susceptible population. A disease can spread if R0 > 1, but if R0 < 1, chains of transmission will inevitably die out. Hence, the goal of control policies is to reduce R0 to levels below 1. However, from this simulation model, Ferguson concluded that a number of key criteria must be met for a high probability of success: (1) rapid identification of the original case cluster, (2) rapid, sensitive case detection and delivery of treatment to targeted groups, (3) effective delivery of treatment to a high proportion of the targeted population, (4) sufficient stockpiles of drug, (5) population co-operation with the containment strategy and, in particular, any social distance measures introduced,

(6) international co-operation in policy development, epidemic surveillance and control strategy implementation. Successful containment is unlikely if R0 exceeds 1.8 for the new pandemic strain.

In a stochastic influenza simulation model using a similar approach (Longini 2005), it was suggested that combinations of targeted antiviral prophylaxis, prevaccination, and quarantine could contain strains with an R0 as high as 2.4. In fact, the World Health Organisation welcomed both the pandemic influenza response modelling papers aforementioned (WHO 2005g). However, there are critical arguments with respect to the simulation models. For example, it has been noticed that Longini’s article assumed that oseltamivir would be useful in a pandemic, but oseltamivir may not be effective on all new avian flu viruses (Chung 2005). Moreover, oseltamivir was ineffective in 50 % of patients in Thailand (Fergusson 2005). Handling the ever-changing disease pattern of pandemic avian influenza requires a contingency plan to prepare for the worst scenario. Such a worst-case scenario model provides valuable information for resource planning, for example, the number of ventilators, the amount of intensive care, and even funeral facilities that will be required (Chung 2005).

Measures to increase the social distance have been used in past pandemics and remain important options for responding to future pandemics (WHO 2005f). These measures include travel or movement restrictions (leaving and entering areas where infection is established), closure of educational institutions, prohibition of mass gatherings, isolation of infected persons and those suspected of being infected, and quarantine of exposed individuals or travellers from areas where pandemic strain influenza infection is established (WHO 2005e). However, the effectiveness of some distancing measures that were successfully implemented for the contention of SARS remains to be demonstrated for influenza. The reason for this is that SARS patients are not infectious prior to the onset of illness, whereas influenza patients are infectious before they develop apparent symptoms (Ho 2004).

Tracing of Symptomatic Cases

Influenza is predicted to be very difficult to control using contact tracing because of the high level of presymptomatic transmission. In addition, contact tracing for influenza would probably be unfeasible because of the very short incubation (2 days) and infectious (3–4 days) periods of that disease (Fraser 2004).

Border Control

During the SARS outbreak, body temperature screening was commonly performed on air passengers. This way, individuals with fever were prohibited from boarding