Integrating surveillance and biosecurity activities to achieve efficiencies in national avian influenza programs.

Based on the HPAI experience, efforts to improve global capacity to prevent and control zoonotic diseases should consider new and more efficient models for integrating prevention and surveillance activities.

Impact of vaccination against chicken Newcastle disease on food intake and food security in rural households in Tanzania.

BACKGROUND: Small-scale poultry production has the potential to increase animal-source food consumption, improve household income, and reduce food insecurity. OBJECTIVE: To assess the impact of a chicken Newcastle disease vaccination program on consumption of chicken and eggs among women and children, income, and food insecurity in rural Tanzanian households. METHODS: Comparisons were made between households from three project villages, which participated in a Newcastle disease vaccination program for chickens, and three control villages, which did not participate. Household interviews were done with mothers from a random sample in March 2008 (237 households) and March 2009 (261 households). RESULTS: After the first year of vaccinations (three rounds), project households kept significantly more chickens and tended to be more food secure than control households. Mothers from project households ate significantly more eggs than their counterparts in control households. A similar trend was observed among children. In 2009, fewer chickens were vaccinated in the project villages than in 2008, and more chickens were independently vaccinated in the control villages. This corresponded with an increase in ownership of chickens, a reduction in food insecurity, and improved consumption of eggs in control villages, whereas chicken ownership and egg consumption decreased and food insecurity remained relatively stable in project villages. We saw no differences between project and control villages in income earned from chicken and egg sales. CONCLUSIONS: Our findings suggest that an increase in chicken Newcastle disease vaccination can lead to an increase in ownership of chickens and egg consumption and may also have an effect on reducing household food insecurity.

Implementing poultry vaccination and biosecurity at the village level in Tanzania: a social strategy to promote health in free-range poultry populations.

A social strategy was tested for implementing Newcastle disease (ND) vaccination and biosecurity improvements among free-ranging chicken at village level in Tanzania. In addition to training the local poultry vaccinators, data recorders and poultry-keepers, the strategy involved training and empowering leaders at the district, ward and village level. The trainings covered poultry health, management, and marketing of village chickens, with an emphasis on ND vaccination and improving biosecurity against avian influenza (AI), The study sites included villages in one ward in each of three each three districts (Iringa, Mtwara-Mikindani, and Mvomero) of mainland Tanzania. Ninety-six local leaders at district level and 101 leaders at ward levels were trained. In addition, 196 farmers (households) were trained, as well as 86 vaccinators and 26 data recorders. Data recorders were also trained as poultry first aid workers. ND vaccination was conducted by the vaccinators, supervised by their local leaders with technical assistance from veterinarians. A total of 158,343 village chickens were vaccinated in three rounds of vaccination three months apart. The training and empowerment of local leaders and local implementers was the key element for success as it fostered the feeling of local ownership of the program and prevented conflicts with other development activities within the villages. We conclude that most animal health programs will increase their odds of success by involving local leaders and by addressing the current challenges facing the farmers. Further assessment on the usefulness of this approach is needed.

Spatial distribution of free-of-charge pathology submissions to the California Animal Health and Food Safety laboratories during the exotic Newcastle outbreak in 2002-2003.

After the 1971-1973 outbreak of exotic Newcastle disease (END) in California, a free-of-charge diagnostic submission program was created for backyard poultry flocks. This program was implemented to improve disease surveillance in small poultry flocks. The aim of this study was to evaluate the spatial distribution of free-of-charge pathology submissions to the California Animal Health and Food Safety laboratories during the END outbreak in 2002-2003. Cases and controls were selected from within a 100-mile (161-km) radius of each of three laboratories, and their geographic distributions were evaluated. Global clustering of cases was significant around all three laboratories, with mixed results at the local clustering level and the only significant clustering at the focal level around the Davis laboratory with an observed to expected ratio of approximately 5. The area of influence for all three laboratories was about 20 miles (32 km). The significant clustering of cases around the laboratories indicates that more public information about the free-of-charge program could result in coverage of a larger portion of the population; however, the value of the information resulting from increased sampling should be considered relative to the additional cost of obtaining it.

Simulation of an early warning system using sentinel birds to detect a change of a low pathogenic avian influenza virus (LPAIV) to high pathogenic avian influenza virus (HPAIV).

The placement of sentinel birds in a commercial poultry flock infected with low pathogenic avian influenza virus (LPAIV) may be an effective way of detecting subsequent change in the isolate to a high pathogenic avian influenza virus (HPAIV). Data collected from the 2002 Chilean HPAIV outbreak, along with information from a literature review of laboratory studies involving A/chicken/Chile/176822/02 (H7N3/LP) and A/chicken/Chile/184240-1/02 (H7N3/HP) viruses, were used to construct a computer simulation model. Mortality rates of the original LPAIV-infected population and the sentinel population were compared to detect the presence of HPAIV. A total of 12 increased mortality threshold scenarios were examined, using one-day absolute (2, 3, or 4 birds) or relative (0.5, 1.0, or 1.5%) mortality thresholds, and two-day absolute (1, 2, or 3 birds) or relative (0.25, 0.50, or 1.00%) mortality thresholds, to indicate the change from LPAIV to HPAIV in the sentinel and original populations, respectively. Results showed that following a one-day approach, threshold mortalities occurred on average at 7.35, 7.82, and 8.17 (0.5, 1.0, or 1.5%) and 6.21, 6.38, and 6.45 (2, 3, or 4 birds) days after the first infectious case for the original and sentinel populations, respectively. The two-day approach delayed the occurrence of threshold mortalities, on average, to 7.64, 8.05, and 8.62 (0.25, 0.50, or 1.00%) and 6.86, 6.78, and 7.23 (1, 2, or 3 birds) days after the first infectious case for the original and sentinel populations, respectively. Although, significant (p<0.10) differences were observed among different combinations of detection times for the original and sentinel populations, the use of sentinel birds has a maximum mean advantage, over monitoring mortality exclusively in the original population, of 1.96 and 1.84 days for one- and two-day threshold moralities, respectively. Additionally, the early warning system based on a sentinel vs. original population presented a decrease of the probabilities of a false alarm, from 0.04-0.45 to <0.01-0.10%. These findings may be used by decision makers to evaluate the risk of not depopulating a flock infected with a H5 or H7 LPAIV strain and the benefit of using sentinel birds as an early warning system of a change to HPAIV.