Dept title


Current state of knowledge on Highly Pathogenic Avian Influenza

2.5 Speed of Detection and Response to Virus Incursions

As with all emergency diseases, the speed of detection of HPAI is considered to be a major determinant of the extent of subsequent spread. In many countries in Asia, it appears that late recognition or late acknowledgement of the presence of H5N1 HPAI led to widespread dispersal of the viruses before effective, coordinated action was taken to control the disease. In places with various combinations of moderate to high poultry (and human) densities, poorly regulated large live-bird markets and/or high populations of domestic ducks, infection became 'endemic' (Chen et al, 2006c). Such countries included Thailand, Viet Nam, China and Indonesia, all of which have since implemented expensive control strategies to reduce the impact of the virus. Most have apparently been successful in reducing the level of infection, while some are in the process of developing infection-free compartments and/or zones.

There are a number of factors that influence the timeliness of reporting of – and thus the response to – H5N1 HPAI. Industrialized farms often have the technical support and infrastructure to detect and respond to outbreaks of the disease far more rapidly than small commercial farms and villages. This is due in part to the lack of access to veterinary services for these smaller holdings. Veterinary paraprofessionals are available in some countries for village level poultry, but their level of expertise in poultry disease diagnosis and control is often limited and their numbers small. Furthermore, in some countries, villagers do not necessarily seek assistance from veterinary paraprofessionals in the event of disease outbreaks in their scavenging poultry (Sims, 2007). A number of donor-funded projects are now in place aimed at increasing the level of support from veterinary paraprofessionals to smallholders and village level flocks.

Villagers do not always report disease when it occurs given the regular die-offs of poultry that occur from diseases such as Newcastle disease, infectious bursal disease, duck virus enteritis and, now, HPAI. Such die-offs are considered part of the normal production process in a low-input production system.

While the control of H5N1 HPAI relies on early reporting of disease, farmers across all production sectors have been guilty of failing to report suspicious cases. In some places, this has been due to genuine mistaken identity or failure to recognize that infection was present (especially in subclinically infected ducks), but in other cases concerns about the consequences of reporting have led to hiding of disease (see for example Nishiguchi et al, 2005).

Although it has been suggested that compensation is an incentive for farmers to report disease (World Bank, 2006), field observations suggest this relationship is weak when livelihoods are at stake or when high value birds such as fighting cocks are involved.  Compensation usually only provides part payment for the loss of culled poultry and in most countries does not extend to reimbursement for consequential losses, which can far exceed the value of the destroyed poultry. Therefore, although absence of a compensation system means there is no incentive to report, the payment of compensation does not guarantee that reports will be forthcoming. For example, HKSAR provided generous compensation to farmers, but this still did not prevent one farmer from selling infected poultry to market in 2002 (Sims et al, 2003b). Some studies are currently in progress to examine the factors that motivate farmers to report disease and these are expected to assist in determining strategies for enhancing cooperation and early reporting.

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